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Sample records for human sensorimotor cortex

  1. A probabilistic map of the human ventral sensorimotor cortex using electrical stimulation.

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    Breshears, Jonathan D; Molinaro, Annette M; Chang, Edward F

    2015-08-01

    The human ventral sensorimotor cortex (vSMC) is involved in facial expression, mastication, and swallowing, as well as the dynamic and highly coordinated movements of human speech production. However, vSMC organization remains poorly understood, and previously published population-driven maps of its somatotopy do not accurately reflect the variability across individuals in a quantitative, probabilistic fashion. The goal of this study was to describe the responses to electrical stimulation of the vSMC, generate probabilistic maps of function in the vSMC, and quantify the variability across individuals. Photographic, video, and stereotactic MRI data of intraoperative electrical stimulation of the vSMC were collected for 33 patients undergoing awake craniotomy. Stimulation sites were converted to a 2D coordinate system based on anatomical landmarks. Motor, sensory, and speech stimulation responses were reviewed and classified. Probabilistic maps of stimulation responses were generated, and spatial variance was quantified. In 33 patients, the authors identified 194 motor, 212 sensory, 61 speech-arrest, and 27 mixed responses. Responses were complex, stereotyped, and mostly nonphysiological movements, involving hand, orofacial, and laryngeal musculature. Within individuals, the presence of oral movement representations varied; however, the dorsal-ventral order was always preserved. The most robust motor responses were jaw (probability 0.85), tongue (0.64), lips (0.58), and throat (0.52). Vocalizations were seen in 6 patients (0.18), more dorsally near lip and dorsal throat areas. Sensory responses were spatially dispersed; however, patients' subjective reports were highly precise in localization within the mouth. The most robust responses included tongue (0.82) and lips (0.42). The probability of speech arrest was 0.85, highest 15-20 mm anterior to the central sulcus and just dorsal to the sylvian fissure, in the anterior precentral gyrus or pars opercularis. The

  2. Gesture Decoding Using ECoG Signals from Human Sensorimotor Cortex: A Pilot Study

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    Yue Li

    2017-01-01

    Full Text Available Electrocorticography (ECoG has been demonstrated as a promising neural signal source for developing brain-machine interfaces (BMIs. However, many concerns about the disadvantages brought by large craniotomy for implanting the ECoG grid limit the clinical translation of ECoG-based BMIs. In this study, we collected clinical ECoG signals from the sensorimotor cortex of three epileptic participants when they performed hand gestures. The ECoG power spectrum in hybrid frequency bands was extracted to build a synchronous real-time BMI system. High decoding accuracy of the three gestures was achieved in both offline analysis (85.7%, 84.5%, and 69.7% and online tests (80% and 82%, tested on two participants only. We found that the decoding performance was maintained even with a subset of channels selected by a greedy algorithm. More importantly, these selected channels were mostly distributed along the central sulcus and clustered in the area of 3 interelectrode squares. Our findings of the reduced and clustered distribution of ECoG channels further supported the feasibility of clinically implementing the ECoG-based BMI system for the control of hand gestures.

  3. Computer-aided training sensorimotor cortex functions in humans before the upper limb transplantation using virtual reality and sensory feedback.

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    Kurzynski, Marek; Jaskolska, Anna; Marusiak, Jaroslaw; Wolczowski, Andrzej; Bierut, Przemyslaw; Szumowski, Lukasz; Witkowski, Jerzy; Kisiel-Sajewicz, Katarzyna

    2017-08-01

    One of the biggest problems of upper limb transplantation is lack of certainty as to whether a patient will be able to control voluntary movements of transplanted hands. Based on findings of the recent research on brain cortex plasticity, a premise can be drawn that mental training supported with visual and sensory feedback can cause structural and functional reorganization of the sensorimotor cortex, which leads to recovery of function associated with the control of movements performed by the upper limbs. In this study, authors - based on the above observations - propose the computer-aided training (CAT) system, which generating visual and sensory stimuli, should enhance the effectiveness of mental training applied to humans before upper limb transplantation. The basis for the concept of computer-aided training system is a virtual hand whose reaching and grasping movements the trained patient can observe on the VR headset screen (visual feedback) and whose contact with virtual objects the patient can feel as a touch (sensory feedback). The computer training system is composed of three main components: (1) the system generating 3D virtual world in which the patient sees the virtual limb from the perspective as if it were his/her own hand; (2) sensory feedback transforming information about the interaction of the virtual hand with the grasped object into mechanical vibration; (3) the therapist's panel for controlling the training course. Results of the case study demonstrate that mental training supported with visual and sensory stimuli generated by the computer system leads to a beneficial change of the brain activity related to motor control of the reaching in the patient with bilateral upper limb congenital transverse deficiency. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Differential recruitment of the sensorimotor putamen and frontoparietal cortex during motor chunking in humans.

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    Wymbs, Nicholas F; Bassett, Danielle S; Mucha, Peter J; Porter, Mason A; Grafton, Scott T

    2012-06-07

    Motor chunking facilitates movement production by combining motor elements into integrated units of behavior. Previous research suggests that chunking involves two processes: concatenation, aimed at the formation of motor-motor associations between elements or sets of elements, and segmentation, aimed at the parsing of multiple contiguous elements into shorter action sets. We used fMRI to measure the trial-wise recruitment of brain regions associated with these chunking processes as healthy subjects performed a cued-sequence production task. A dynamic network analysis identified chunking structure for a set of motor sequences acquired during fMRI and collected over 3 days of training. Activity in the bilateral sensorimotor putamen positively correlated with chunk concatenation, whereas a left-hemisphere frontoparietal network was correlated with chunk segmentation. Across subjects, there was an aggregate increase in chunk strength (concatenation) with training, suggesting that subcortical circuits play a direct role in the creation of fluid transitions across chunks. Copyright © 2012 Elsevier Inc. All rights reserved.

  5. Beta Peak Frequencies at Rest Correlate with Endogenous GABA+/Cr Concentrations in Sensorimotor Cortex Areas.

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    Thomas J Baumgarten

    Full Text Available Neuronal oscillatory activity in the beta band (15-30 Hz is a prominent signal within the human sensorimotor cortex. Computational modeling and pharmacological modulation studies suggest an influence of GABAergic interneurons on the generation of beta band oscillations. Accordingly, studies in humans have demonstrated a correlation between GABA concentrations and power of beta band oscillations. It remains unclear, however, if GABA concentrations also influence beta peak frequencies and whether this influence is present in the sensorimotor cortex at rest and without pharmacological modulation. In the present study, we investigated the relation between endogenous GABA concentration (measured by magnetic resonance spectroscopy and beta oscillations (measured by magnetoencephalography at rest in humans. GABA concentrations and beta band oscillations were measured for left and right sensorimotor and occipital cortex areas. A significant positive linear correlation between GABA concentration and beta peak frequency was found for the left sensorimotor cortex, whereas no significant correlations were found for the right sensorimotor and the occipital cortex. The results show a novel connection between endogenous GABA concentration and beta peak frequency at rest. This finding supports previous results that demonstrated a connection between oscillatory beta activity and pharmacologically modulated GABA concentration in the sensorimotor cortex. Furthermore, the results demonstrate that for a predominantly right-handed sample, the correlation between beta band oscillations and endogenous GABA concentrations is evident only in the left sensorimotor cortex.

  6. Beta Peak Frequencies at Rest Correlate with Endogenous GABA+/Cr Concentrations in Sensorimotor Cortex Areas

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    Baumgarten, Thomas J.; Oeltzschner, Georg; Hoogenboom, Nienke; Wittsack, Hans-Jörg; Schnitzler, Alfons; Lange, Joachim

    2016-01-01

    Neuronal oscillatory activity in the beta band (15–30 Hz) is a prominent signal within the human sensorimotor cortex. Computational modeling and pharmacological modulation studies suggest an influence of GABAergic interneurons on the generation of beta band oscillations. Accordingly, studies in humans have demonstrated a correlation between GABA concentrations and power of beta band oscillations. It remains unclear, however, if GABA concentrations also influence beta peak frequencies and whether this influence is present in the sensorimotor cortex at rest and without pharmacological modulation. In the present study, we investigated the relation between endogenous GABA concentration (measured by magnetic resonance spectroscopy) and beta oscillations (measured by magnetoencephalography) at rest in humans. GABA concentrations and beta band oscillations were measured for left and right sensorimotor and occipital cortex areas. A significant positive linear correlation between GABA concentration and beta peak frequency was found for the left sensorimotor cortex, whereas no significant correlations were found for the right sensorimotor and the occipital cortex. The results show a novel connection between endogenous GABA concentration and beta peak frequency at rest. This finding supports previous results that demonstrated a connection between oscillatory beta activity and pharmacologically modulated GABA concentration in the sensorimotor cortex. Furthermore, the results demonstrate that for a predominantly right-handed sample, the correlation between beta band oscillations and endogenous GABA concentrations is evident only in the left sensorimotor cortex. PMID:27258089

  7. Prediction of three-dimensional arm trajectories based on ECoG signals recorded from human sensorimotor cortex.

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    Yasuhiko Nakanishi

    Full Text Available Brain-machine interface techniques have been applied in a number of studies to control neuromotor prostheses and for neurorehabilitation in the hopes of providing a means to restore lost motor function. Electrocorticography (ECoG has seen recent use in this regard because it offers a higher spatiotemporal resolution than non-invasive EEG and is less invasive than intracortical microelectrodes. Although several studies have already succeeded in the inference of computer cursor trajectories and finger flexions using human ECoG signals, precise three-dimensional (3D trajectory reconstruction for a human limb from ECoG has not yet been achieved. In this study, we predicted 3D arm trajectories in time series from ECoG signals in humans using a novel preprocessing method and a sparse linear regression. Average Pearson's correlation coefficients and normalized root-mean-square errors between predicted and actual trajectories were 0.44~0.73 and 0.18~0.42, respectively, confirming the feasibility of predicting 3D arm trajectories from ECoG. We foresee this method contributing to future advancements in neuroprosthesis and neurorehabilitation technology.

  8. Post-Movement Beta Activity in Sensorimotor Cortex Indexes Confidence in the Estimations from Internal Models.

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    Tan, Huiling; Wade, Cian; Brown, Peter

    2016-02-03

    Beta oscillations are a dominant feature of the sensorimotor system. A transient and prominent increase in beta oscillations is consistently observed across the sensorimotor cortical-basal ganglia network after cessation of voluntary movement: the post-movement beta synchronization (PMBS). Current theories about the function of the PMBS have been focused on either the closure of motor response or the processing of sensory afferance. Computational models of sensorimotor control have emphasized the importance of the integration between feedforward estimation and sensory feedback, and therefore the putative motor and sensory functions of beta oscillations may reciprocally interact with each other and in fact be indissociable. Here we show that the amplitude of sensorimotor PMBS is modulated by the history of visual feedback of task-relevant errors, and negatively correlated with the trial-to-trial exploratory adjustment in a sensorimotor adaptation task in young healthy human subjects. The PMBS also negatively correlated with the uncertainty associated with the feedforward estimation, which was recursively updated in light of new sensory feedback, as identified by a Bayesian learning model. These results reconcile the two opposing motor and sensory views of the function of PMBS, and suggest a unifying theory in which PMBS indexes the confidence in internal feedforward estimation in Bayesian sensorimotor integration. Its amplitude simultaneously reflects cortical sensory processing and signals the need for maintenance or adaptation of the motor output, and if necessary, exploration to identify an altered sensorimotor transformation. For optimal sensorimotor control, sensory feedback and feedforward estimation of a movement's sensory consequences should be weighted by the inverse of their corresponding uncertainties, which require recursive updating in a dynamic environment. We show that post-movement beta activity (13-30 Hz) over sensorimotor cortex in young healthy

  9. Sensorimotor learning configures the human mirror system.

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    Catmur, Caroline; Walsh, Vincent; Heyes, Cecilia

    2007-09-04

    Cells in the "mirror system" fire not only when an individual performs an action but also when one observes the same action performed by another agent [1-4]. The mirror system, found in premotor and parietal cortices of human and monkey brains, is thought to provide the foundation for social understanding and to enable the development of theory of mind and language [5-9]. However, it is unclear how mirror neurons acquire their mirror properties -- how they derive the information necessary to match observed with executed actions [10]. We address this by showing that it is possible to manipulate the selectivity of the human mirror system, and thereby make it operate as a countermirror system, by giving participants training to perform one action while observing another. Before this training, participants showed event-related muscle-specific responses to transcranial magnetic stimulation over motor cortex during observation of little- and index-finger movements [11-13]. After training, this normal mirror effect was reversed. These results indicate that the mirror properties of the mirror system are neither wholly innate [14] nor fixed once acquired; instead they develop through sensorimotor learning [15, 16]. Our findings indicate that the human mirror system is, to some extent, both a product and a process of social interaction.

  10. Timing-dependent modulation of the posterior parietal cortex-primary motor cortex pathway by sensorimotor training

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    Karabanov, Anke Ninija; Jin, Seung-Hyun; Joutsen, Atte

    2012-01-01

    at baseline and at four time points (0, 30, 60, and 180 min) after training. For EEG, task-related power and coherence were calculated for early and late training phases. The conditioned MEP was facilitated at a 2-ms conditioning-test interval before training. However, facilitation was abolished immediately...... following training, but returned to baseline at subsequent time points. Regional EEG activity and interregional connectivity between PPC and M1 showed an initial increase during early training followed by a significant decrease in the late phases. The findings indicate that parietal-motor interactions......Interplay between posterior parietal cortex (PPC) and ipsilateral primary motor cortex (M1) is crucial during execution of movements. The purpose of the study was to determine whether functional PPC-M1 connectivity in humans can be modulated by sensorimotor training. Seventeen participants...

  11. Encoding of temporal intervals in the rat hindlimb sensorimotor cortex

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    Eric Bean Knudsen

    2012-09-01

    Full Text Available The gradual buildup of neural activity over experimentally imposed delay periods, termed climbing activity, is well documented and is a potential mechanism by which interval time is encoded by distributed cortico-thalamico-striatal networks in the brain. Additionally, when multiple delay periods are incorporated, this activity has been shown to scale its rate of climbing proportional to the delay period. However, it remains unclear whether these patterns of activity occur within areas of motor cortex dedicated to hindlimb movement. Moreover, the effects of behavioral training (e.g. motor tasks under different reward conditions but with similar behavioral output are not well addressed. To address this, we recorded activity from the hindlimb sensorimotor cortex (HLSMC of two groups of rats performing a skilled hindlimb press task. In one group, rats were trained only to a make a valid press within a finite window after cue presentation for reward (non-interval trained, nIT; n=5, while rats in the second group were given duration-specific cues in which they had to make presses of either short or long duration to receive reward (interval trained, IT; n=6. Using PETH analyses, we show that cells recorded from both groups showed climbing activity during the task in similar proportions (35% IT and 47% nIT, however only climbing activity from IT rats was temporally scaled to press duration. Furthermore, using single trial decoding techniques (Wiener filter, we show that press duration can be inferred using climbing activity from IT animals (R=0.61 significantly better than nIT animals (R=0.507, p<0.01, suggesting IT animals encode press duration through temporally scaled climbing activity. Thus, if temporal intervals are behaviorally relevant then the activity of climbing neurons is temporally scaled to encode the passage of time.

  12. Decoding bipedal locomotion from the rat sensorimotor cortex

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    Rigosa, J.; Panarese, A.; Dominici, N.; Friedli, L.; van den Brand, R.; Carpaneto, J.; DiGiovanna, J.; Courtine, G.; Micera, S.

    2015-10-01

    Objective. Decoding forelimb movements from the firing activity of cortical neurons has been interfaced with robotic and prosthetic systems to replace lost upper limb functions in humans. Despite the potential of this approach to improve locomotion and facilitate gait rehabilitation, decoding lower limb movement from the motor cortex has received comparatively little attention. Here, we performed experiments to identify the type and amount of information that can be decoded from neuronal ensemble activity in the hindlimb area of the rat motor cortex during bipedal locomotor tasks. Approach. Rats were trained to stand, step on a treadmill, walk overground and climb staircases in a bipedal posture. To impose this gait, the rats were secured in a robotic interface that provided support against the direction of gravity and in the mediolateral direction, but behaved transparently in the forward direction. After completion of training, rats were chronically implanted with a micro-wire array spanning the left hindlimb motor cortex to record single and multi-unit activity, and bipolar electrodes into 10 muscles of the right hindlimb to monitor electromyographic signals. Whole-body kinematics, muscle activity, and neural signals were simultaneously recorded during execution of the trained tasks over multiple days of testing. Hindlimb kinematics, muscle activity, gait phases, and locomotor tasks were decoded using offline classification algorithms. Main results. We found that the stance and swing phases of gait and the locomotor tasks were detected with accuracies as robust as 90% in all rats. Decoded hindlimb kinematics and muscle activity exhibited a larger variability across rats and tasks. Significance. Our study shows that the rodent motor cortex contains useful information for lower limb neuroprosthetic development. However, brain-machine interfaces estimating gait phases or locomotor behaviors, instead of continuous variables such as limb joint positions or speeds

  13. Responsiveness of sensorimotor cortex during pharmacological intervention with bromazepam.

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    Cunha, Marlo; Portela, Cláudio; Bastos, Victor H; Machado, Dionis; Machado, Sergio; Velasques, Bruna; Budde, Henning; Cagy, Maurício; Basile, Luis; Piedade, Roberto; Ribeiro, Pedro

    2008-12-19

    The aim of this study was to investigate the influence of bromazepam on EEG and the motor learning process when healthy subjects were submitted to a typewriting task. We investigated bromazepam due to its abuse by various populations and its prevalent clinical use among older individuals which are more sensitive to the negative effects of long half-life benzodiazepines. A randomized double-blind design was used with subjects divided into three groups: placebo (n=13), bromazepam 3mg (n=13) and bromazepam 6 mg (n=13). EEG data comprising theta, alpha and beta bands was recorded before, during and after the motor task. Our results showed a lower relative power value in the theta band in the Br 6 mg group when compared with PL. We also observed a reduction in relative power in the beta band in the Br 3mg and Br 6 mg when compared with PL group. These findings suggest that Br can contribute to a reduced working memory load in areas related to attention processes. On the other hand, it produces a higher cortical activation in areas associated with sensory integration. Such areas are responsible for accomplishing the motor learning task. The results are an example of the usefulness of integrating electrophysiological data, sensorimotor activity and a pharmacological approach to aid in our understanding of cerebral changes produced by external agents.

  14. Neuronal synchronization in human parietal cortex during saccade planning

    NARCIS (Netherlands)

    Werf, J. van der; Buchholz, V.N.; Jensen, O.; Medendorp, W.P.

    2009-01-01

    Neuropsychological and neuroimaging studies have implicated the human posterior parietal cortex (PPC) in sensorimotor integration and saccade planning However, the temporal dynamics of the underlying physiology and its relationship to observations in non-human primates have been difficult to pin

  15. Decoding bipedal locomotion from the rat sensorimotor cortex

    NARCIS (Netherlands)

    Rigosa, J.; Panarese, A.; Dominici, N.; Friedli, L.; van den Brand, R.; Carpaneto, J.; DiGiovanna, J.; Courtine, G.; Micera, S.

    2015-01-01

    Objective. Decoding forelimb movements from the firing activity of cortical neurons has been interfaced with robotic and prosthetic systems to replace lost upper limb functions in humans. Despite the potential of this approach to improve locomotion and facilitate gait rehabilitation, decoding lower

  16. Eye muscle proprioception is represented bilaterally in the sensorimotor cortex

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    Balslev, Daniela; Albert, Neil B; Miall, Chris

    2011-01-01

    eye after a virtual lesion with rTMS over the left somatosensory area. However, it is possible that the proprioceptive representation of the EOM extends to other brain sites, which were not examined in these previous studies. The aim of this fMRI study was to sample the whole brain to identify...... the proprioceptive representation for the left and the right eye separately. Data were acquired while passive eye movement was used to stimulate EOM proprioceptors in the absence of a motor command. We also controlled for the tactile stimulation of the eyelid by removing from the analysis voxels activated by eyelid......The cortical representation of eye position is still uncertain. In the monkey a proprioceptive representation of the extraocular muscles (EOM) of an eye were recently found within the contralateral central sulcus. In humans, we have previously shown a change in the perceived position of the right...

  17. Expressions of multiple neuronal dynamics during sensorimotor learning in the motor cortex of behaving monkeys.

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    Yael Mandelblat-Cerf

    Full Text Available Previous studies support the notion that sensorimotor learning involves multiple processes. We investigated the neuronal basis of these processes by recording single-unit activity in motor cortex of non-human primates (Macaca fascicularis, during adaptation to force-field perturbations. Perturbed trials (reaching to one direction were practiced along with unperturbed trials (to other directions. The number of perturbed trials relative to the unperturbed ones was either low or high, in two separate practice schedules. Unsurprisingly, practice under high-rate resulted in faster learning with more pronounced generalization, as compared to the low-rate practice. However, generalization and retention of behavioral and neuronal effects following practice in high-rate were less stable; namely, the faster learning was forgotten faster. We examined two subgroups of cells and showed that, during learning, the changes in firing-rate in one subgroup depended on the number of practiced trials, but not on time. In contrast, changes in the second subgroup depended on time and practice; the changes in firing-rate, following the same number of perturbed trials, were larger under high-rate than low-rate learning. After learning, the neuronal changes gradually decayed. In the first subgroup, the decay pace did not depend on the practice rate, whereas in the second subgroup, the decay pace was greater following high-rate practice. This group shows neuronal representation that mirrors the behavioral performance, evolving faster but also decaying faster at learning under high-rate, as compared to low-rate. The results suggest that the stability of a new learned skill and its neuronal representation are affected by the acquisition schedule.

  18. Chronological changes in astrocytes induced by chronic electrical sensorimotor cortex stimulation in rats.

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    Morishita, Takashi; Yamashita, Akiko; Katayama, Yoichi; Oshima, Hideki; Nishizaki, Yuji; Shijo, Katsunori; Fukaya, Chikashi; Yamamoto, Takamitsu

    2011-01-01

    Motor cortex stimulation (MCS) is a treatment option for various disorders such as medically refractory pain, poststroke hemiplegia, and movement disorders. However, the exact mechanisms underlying its effects remain unknown. In this study, the effects of long-term chronic MCS were investigated by observing changes in astrocytes. A quadripolar stimulation electrode was implanted on the dura over the sensorimotor cortex of adult rats, and the cortex was continuously stimulated for 3 hours, 1 week, 4 weeks, and 8 weeks. Immunohistochemical staining of microglia (ionized calcium-binding adaptor molecule 1 [Iba1] staining) and astrocytes (glial fibrillary acidic protein [GFAP] staining), and neuronal degeneration histochemistry (Fluoro-Jade B staining) were carried out to investigate the morphological changes following long-term chronic MCS. Iba1 staining and Fluoro-Jade B staining showed no evidence of Iba1-positive microglial changes or neurodegeneration. Following continuous MCS, GFAP-positive astrocytes were enlarged and their number increased in the cortex and the thalamus of the stimulated hemisphere. These findings indicate that chronic electrical stimulation can continuously activate astrocytes and result in morphological and quantitative changes. These changes may be involved in the mechanisms underlying the neuroplasticity effect induced by MCS.

  19. Effects of bilateral and unilateral locus coeruleus lesions on beam-walking recovery after subsequent unilateral sensorimotor cortex suction-ablation in the rat.

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    Goldstein, L B

    1997-01-01

    The recovery of beam-walking ability following a unilateral sensorimotor cortex lesion in the rat is hypothesized to be noradrenergically-mediated. We carried out two experiments to further test this hypothesis. In the first experiment, bilateral 6-hydroxydopamine locus coeruleus (LC) lesions or sham LC lesions were made 2 weeks prior to a right sensorimotor cortex suction-ablation lesion or sham cortex lesion. In the second experiment, unilateral left or right LC lesions or sham LC lesions were made 2 weeks prior to a right sensorimotor cortex lesion or sham cortex lesion. Beam-walking recovery was measured over the 12 days following cortex lesioning in each experiment. Bilateral, unilateral left, and unilateral right LC lesions resulted in impaired recovery. These data provide additional support for the hypothesis that beam-walking recovery after sensorimotor cortex injury is, at least in part, noradrenergically mediated.

  20. Body Topography Parcellates Human Sensory and Motor Cortex.

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    Kuehn, Esther; Dinse, Juliane; Jakobsen, Estrid; Long, Xiangyu; Schäfer, Andreas; Bazin, Pierre-Louis; Villringer, Arno; Sereno, Martin I; Margulies, Daniel S

    2017-07-01

    The cytoarchitectonic map as proposed by Brodmann currently dominates models of human sensorimotor cortical structure, function, and plasticity. According to this model, primary motor cortex, area 4, and primary somatosensory cortex, area 3b, are homogenous areas, with the major division lying between the two. Accumulating empirical and theoretical evidence, however, has begun to question the validity of the Brodmann map for various cortical areas. Here, we combined in vivo cortical myelin mapping with functional connectivity analyses and topographic mapping techniques to reassess the validity of the Brodmann map in human primary sensorimotor cortex. We provide empirical evidence that area 4 and area 3b are not homogenous, but are subdivided into distinct cortical fields, each representing a major body part (the hand and the face). Myelin reductions at the hand-face borders are cortical layer-specific, and coincide with intrinsic functional connectivity borders as defined using large-scale resting state analyses. Our data extend the Brodmann model in human sensorimotor cortex and suggest that body parts are an important organizing principle, similar to the distinction between sensory and motor processing. © The Author 2017. Published by Oxford University Press.

  1. Right vs. left sensorimotor cortex suction-ablation in the rat: no difference in beam-walking recovery.

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    Goldstein, L B

    1995-03-13

    The ability of rats to traverse a narrow elevated beam has been used to quantitate recovery of hindlimb motor function after unilateral injury to the sensorimotor cortex. We tested the hypothesis that the rate of spontaneous beam-walking recovery varies with the side of the cortex lesion. Groups of rats that were trained at the beam-walking task underwent suction-ablation of either the right or left hindlimb sensorimotor cortex. There was no difference in hindlimb motor function between the groups on the first post-operative beam-waking trial carried out the day after cortex ablation and no difference between the groups in overall recovery rates over the next two weeks. Subsequent analyses of lesion surface parameters showed no differences in lesion size or extent. Regardless of the side of the lesion, there were also no differences between the right and left hemispheres in norepinephrine content of the lesioned or contralateral cortex. We conclude that the side of sensorimotor cortex ablation injury does not differentially affect the rate of spontaneous motor recovery as measured with the beam-walking task.

  2. Spontaneous brain activity in the sensorimotor cortex in amyotrophic lateral sclerosis can be negatively regulated by corticospinal fiber integrity.

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    Sako, Wataru; Abe, Takashi; Izumi, Yuishin; Yamazaki, Hiroki; Matsui, Naoko; Harada, Masafumi; Kaji, Ryuji

    2017-05-01

    Previous studies failed to detect reduced value of the amplitude of low frequency fluctuation (ALFF) derived from resting state functional magnetic resonance imaging in the primary motor cortex in amyotrophic lateral sclerosis (ALS) though primary motor cortex was mainly affected with ALS. We aimed to investigate the cause of masking the abnormality in the primary motor cortex in ALS and usefulness of ALFF for differential diagnosis among diseases showing muscle weakness. We enrolled ten patients with ALS and eleven disease controls showing muscle weakness. Voxel-wise analysis revealed that significant reduction of ALFF value was present in the right sensorimotor cortex in ALS. There was a significant negative correlation between ALFF value in the right sensorimotor cortex and fractional anisotropy (FA) value in the posterior limbs of the internal capsule (PLIC). For a diagnostic tool, the area under receiver operating characteristic curve improved if the ALS patients with disease duration >1 year were excluded. The present findings raised the possibility of usefulness of ALFF value in the sensorimotor cortex for differential diagnosis of ALS, and supported the notion that adjustment for FA value in the PLIC could improve accuracy.

  3. Electrocorticographic activity over sensorimotor cortex and motor function in awake behaving rats.

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    Boulay, Chadwick B; Chen, Xiang Yang; Wolpaw, Jonathan R

    2015-04-01

    Sensorimotor cortex exerts both short-term and long-term control over the spinal reflex pathways that serve motor behaviors. Better understanding of this control could offer new possibilities for restoring function after central nervous system trauma or disease. We examined the impact of ongoing sensorimotor cortex (SMC) activity on the largely monosynaptic pathway of the H-reflex, the electrical analog of the spinal stretch reflex. In 41 awake adult rats, we measured soleus electromyographic (EMG) activity, the soleus H-reflex, and electrocorticographic activity over the contralateral SMC while rats were producing steady-state soleus EMG activity. Principal component analysis of electrocorticographic frequency spectra before H-reflex elicitation consistently revealed three frequency bands: μβ (5-30 Hz), low γ (γ1; 40-85 Hz), and high γ (γ2; 100-200 Hz). Ongoing (i.e., background) soleus EMG amplitude correlated negatively with μβ power and positively with γ1 power. In contrast, H-reflex size correlated positively with μβ power and negatively with γ1 power, but only when background soleus EMG amplitude was included in the linear model. These results support the hypothesis that increased SMC activation (indicated by decrease in μβ power and/or increase in γ1 power) simultaneously potentiates the H-reflex by exciting spinal motoneurons and suppresses it by decreasing the efficacy of the afferent input. They may help guide the development of new rehabilitation methods and of brain-computer interfaces that use SMC activity as a substitute for lost or impaired motor outputs. Copyright © 2015 the American Physiological Society.

  4. Functional mapping of the sensorimotor cortex: combined use of magnetoencephalography, functional MRI, and motor evoked potentials

    International Nuclear Information System (INIS)

    Morioka, T.; Fujii, K.; Fukui, M.; Mizushima, A.; Matsumoto, S.; Hasuo, K.; Yamamoto, T.; Tobimatsu, S.

    1995-01-01

    Combined use of magnetoencephalography (MEG), functional magnetic resonance imaging (f-MRI), and motor evoked potentials (MEPs) was carried out on one patient in an attempt to localise precisely a structural lesion to the central sulcus. A small cyst in the right frontoparietal region was thought to be the cause of generalised seizures in an otherwise asymptomatic woman. First the primary sensory cortex was identified with magnetic source imaging (MSI) of somatosensory evoked magnetic fields using MEG and MRI. Second, the motor area of the hand was identified using f-MRI during handsqueezing. Then transcranial magnetic stimulation localised the hand motor area on the scalp, which was mapped onto the MRI. There was a good agreement between MSI, f-MRI and MEP as to the location of the sensorimotor cortex and its relationship to the lesion. Multimodality mapping techniques may thus prove useful in the precise localisation of cortical lesions, and in the preoperative determination of the best treatment for peri-rolandic lesions. (orig.)

  5. Functional mapping of the sensorimotor cortex: combined use of magnetoencephalography, functional MRI, and motor evoked potentials

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    Morioka, T. [Dept. of Neurosurgery, Neurological Inst., Kyshu Univ., Fukuoka (Japan); Fujii, K. [Dept. of Neurosurgery, Neurological Inst., Kyshu Univ., Fukuoka (Japan); Fukui, M. [Dept. of Neurosurgery, Neurological Inst., Kyshu Univ., Fukuoka (Japan); Mizushima, A. [Dept. of Radiology, Kyushu Univ. Fukuoka (Japan); Matsumoto, S. [Dept. of Radiology, Kyushu Univ. Fukuoka (Japan); Hasuo, K. [Dept. of Radiology, Kyushu Univ. Fukuoka (Japan); Yamamoto, T. [Dept. of Otolaryngology, Kyushu Univ. Fukuoka (Japan); Tobimatsu, S. [Dept. of Clinical Neurophysiology, Neurological Inst., Kyushu Univ., Fukuoka (Japan)

    1995-10-01

    Combined use of magnetoencephalography (MEG), functional magnetic resonance imaging (f-MRI), and motor evoked potentials (MEPs) was carried out on one patient in an attempt to localise precisely a structural lesion to the central sulcus. A small cyst in the right frontoparietal region was thought to be the cause of generalised seizures in an otherwise asymptomatic woman. First the primary sensory cortex was identified with magnetic source imaging (MSI) of somatosensory evoked magnetic fields using MEG and MRI. Second, the motor area of the hand was identified using f-MRI during handsqueezing. Then transcranial magnetic stimulation localised the hand motor area on the scalp, which was mapped onto the MRI. There was a good agreement between MSI, f-MRI and MEP as to the location of the sensorimotor cortex and its relationship to the lesion. Multimodality mapping techniques may thus prove useful in the precise localisation of cortical lesions, and in the preoperative determination of the best treatment for peri-rolandic lesions. (orig.)

  6. Gamma knife radiosurgery for arteriovenous malformations located in the sensorimotor cortex

    Energy Technology Data Exchange (ETDEWEB)

    Yamanaka, Kazuhiro; Iwai, Yoshiyasu; Komiyama, Masaki; Nakajima, Hideki; Yasui, Toshihiro; Nishikawa, Misao; Sakamoto, Hiroaki; Morikawa, Toshie [Osaka City General Hospital (Japan)

    2002-05-01

    The goal of this study was to define treatment results of gamma knife radiosurgery (GKS) for arteriovenous malformation (AVM) located in the sensorimotor cortex. We analyzed 27 patients followed up for at least 12 months. The onset of AVM was convulsion 10, clinical hemorrhage 7, neurological deficits 4, and headache 3. The mean diameter of the AVM nidus was 22.2 mm (range 8.5-33.6 mm) and mean volume was 7.4 ml (range 0.32-19.9 ml). According to the Spetzler-Martin scale, the AVMs were Grade II in 13, Grade III in 10, and Grade IV in 4 of the patients. GKS was performed with a mean dose of 19.0 Gy (range 14-25 Gy) to the margin of the nidus. The mean follow-up period was 29 months (range 12-72 months). Six AVMs showed complete obliteration angiographically and 5 AVMs showed obliteration on magnetic resonance image. Sixteen AVMs showed nidus shrinkage. Eight (53%) of 15 patients followed up for more than 24 months showed obliteration. Complications consisted of 32 (11.5%) of 27 patients with evidence of radiation injury to the brain parenchyma. Symptoms of slight hemiparesis resolved completely in all patients within several months. (author)

  7. Electroacupunctre improves motor impairment via inhibition of microglia-mediated neuroinflammation in the sensorimotor cortex after ischemic stroke.

    Science.gov (United States)

    Liu, Weilin; Wang, Xian; Yang, Shanli; Huang, Jia; Xue, Xiehua; Zheng, Yi; Shang, Guanhao; Tao, Jing; Chen, Lidian

    2016-04-15

    Electroacupuncture (EA) is one of the safety and effective therapies for improving neurological and sensorimotor impairment via blockade of inappropriate inflammatory responses. However, the mechanisms of anti-inflammation involved is far from been fully elucidated. Focal cerebral ischemic stroke was administered by the middle cerebral artery occlusion and reperfusion (MCAO/R) surgery. The MCAO/R rats were accepted EA treatment at the LI 11 and ST 36 acupoints for consecutive 3days. The neurological outcome, animal behaviors test and molecular biology assays were used to evaluate the MCAO/R model and therapeutic effect of EA. EA treatment for MCAO rats showed a significant reduction in the infarct volumes accompanied by functional recovery in mNSS outcomes, motor function performances. The possible mechanisms that EA treatment attenuated the over-activation of Iba-1 and ED1 positive microglia in the peri-infract sensorimotor cortex. Simultaneously, both tissue and serum protein levels of the tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) were decreased by EA treatment in MCAO/R injured rats. The levels of inflammatory cytokine tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6) were decreased in the peri-infract sensorimotor cortex and blood serum of MCAO/R injured rats after EA treatment. Furthermore, we found that EA treatment prevented from the nucleus translocation of NF-κB p65 and suppressed the expression of p38 mitogen-activated protein kinase (p38 MAPK) and myeloid differentiation factor 88 (MyD88) in the peri-infract sensorimotor cortex. The findings from this study indicated that EA improved the motor impairment via inhibition of microglia-mediated neuroinflammation that invoked NF-κB p65, p38 MAPK and MyD88 produced proinflammatory cytokine in the peri-infract sensorimotor cortex of rats following ischemic stroke. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Neural Signature of Value-Based Sensorimotor Prioritization in Humans.

    Science.gov (United States)

    Blangero, Annabelle; Kelly, Simon P

    2017-11-01

    In situations in which impending sensory events demand fast action choices, we must be ready to prioritize higher-value courses of action to avoid missed opportunities. When such a situation first presents itself, stimulus-action contingencies and their relative value must be encoded to establish a value-biased state of preparation for an impending sensorimotor decision. Here, we sought to identify neurophysiological signatures of such processes in the human brain (both female and male). We devised a task requiring fast action choices based on the discrimination of a simple visual cue in which the differently valued sensory alternatives were presented 750-800 ms before as peripheral "targets" that specified the stimulus-action mapping for the upcoming decision. In response to the targets, we identified a discrete, transient, spatially selective signal in the event-related potential (ERP), which scaled with relative value and strongly predicted the degree of behavioral bias in the upcoming decision both across and within subjects. This signal is not compatible with any hitherto known ERP signature of spatial selection and also bears novel distinctions with respect to characterizations of value-sensitive, spatially selective activity found in sensorimotor areas of nonhuman primates. Specifically, a series of follow-up experiments revealed that the signal was reliably invoked regardless of response laterality, response modality, sensory feature, and reward valence. It was absent, however, when the response deadline was relaxed and the strategic need for biasing removed. Therefore, more than passively representing value or salience, the signal appears to play a versatile and active role in adaptive sensorimotor prioritization. SIGNIFICANCE STATEMENT In many situations such as fast-moving sports, we must be ready to act fast in response to sensory events and, in our preparation, prioritize courses of action that lead to greater rewards. Although behavioral effects of

  9. Symmetry of fMRI activation in the primary sensorimotor cortex during unilateral chewing.

    Science.gov (United States)

    Lotze, M; Domin, M; Kordass, B

    2017-05-01

    Functional magnetic resonance imaging (fMRI) is one of the most advanced techniques to analyze the cerebral effects on many behavior aspects of the oral system such as chewing and mastication. Studies on imaging of the cerebral representation of chewing demonstrated differential results with respect to cortical lateralization during unilateral chewing. The aim of our study is to clarify the effects of cerebral responses during unilateral chewing. We used fMRI to compare brain activities during occlusal function in centric occlusion on natural teeth and chewing on a gum located on the right or the left teeth in 15 healthy subjects. Group data were performed by Talairach normalization and in addition by an assignment of activation maxima to individual anatomical landmarks in order to avoid possible loss of spatial preciseness of activation sites by normalization procedures. Evaluation of group data by Talairach normalization revealed representation sites for occlusal movements in bilateral primary (S1) and secondary (S2) somatosensory cortices, primary motor (M1) and premotor cortices, supplementary motor area (SMA) and medial cingulate gyrus, bilateral anterior cerebellar hemispheres and vermis, insula, orbitofrontal cortex, thalamus, and left pallidum. Right-sided chewing showed no differential activation to left-sided chewing, and both showed activation in areas also involved in bilateral occlusion. Both techniques, the one based on group normalization and the one based on an individual evaluation method, revealed remarkable low differences in activation maximum location in the primary motor, the primary and secondary somatosensory cortices, and the anterior cerebellar lobe. All chewing movements tested involved bilateral sensorimotor activation without a significant lateralization of activation intensities. Overall, a general lateralization of occlusion movements to the dominant side could not be verified in the present study. Chewing on the left or on the right

  10. From sensorimotor learning to memory cells in prefrontal and temporal association cortex: a neurocomputational study of disembodiment.

    Science.gov (United States)

    Pulvermüller, Friedemann; Garagnani, Max

    2014-08-01

    Memory cells, the ultimate neurobiological substrates of working memory, remain active for several seconds and are most commonly found in prefrontal cortex and higher multisensory areas. However, if correlated activity in "embodied" sensorimotor systems underlies the formation of memory traces, why should memory cells emerge in areas distant from their antecedent activations in sensorimotor areas, thus leading to "disembodiment" (movement away from sensorimotor systems) of memory mechanisms? We modelled the formation of memory circuits in six-area neurocomputational architectures, implementing motor and sensory primary, secondary and higher association areas in frontotemporal cortices along with known between-area neuroanatomical connections. Sensorimotor learning driven by Hebbian neuroplasticity led to formation of cell assemblies distributed across the different areas of the network. These action-perception circuits (APCs) ignited fully when stimulated, thus providing a neural basis for long-term memory (LTM) of sensorimotor information linked by learning. Subsequent to ignition, activity vanished rapidly from APC neurons in sensorimotor areas but persisted in those in multimodal prefrontal and temporal areas. Such persistent activity provides a mechanism for working memory for actions, perceptions and symbols, including short-term phonological and semantic storage. Cell assembly ignition and "disembodied" working memory retreat of activity to multimodal areas are documented in the neurocomputational models' activity dynamics, at the level of single cells, circuits, and cortical areas. Memory disembodiment is explained neuromechanistically by APC formation and structural neuroanatomical features of the model networks, especially the central role of multimodal prefrontal and temporal cortices in bridging between sensory and motor areas. These simulations answer the "where" question of cortical working memory in terms of distributed APCs and their inner structure

  11. Optogenetic Activation of the Sensorimotor Cortex Reveals "Local Inhibitory and Global Excitatory" Inputs to the Basal Ganglia.

    Science.gov (United States)

    Ozaki, Mitsunori; Sano, Hiromi; Sato, Shigeki; Ogura, Mitsuhiro; Mushiake, Hajime; Chiken, Satomi; Nakao, Naoyuki; Nambu, Atsushi

    2017-12-01

    To understand how information from different cortical areas is integrated and processed through the cortico-basal ganglia pathways, we used optogenetics to systematically stimulate the sensorimotor cortex and examined basal ganglia activity. We utilized Thy1-ChR2-YFP transgenic mice, in which channelrhodopsin 2 is robustly expressed in layer V pyramidal neurons. We applied light spots to the sensorimotor cortex in a grid pattern and examined neuronal responses in the globus pallidus (GP) and entopeduncular nucleus (EPN), which are the relay and output nuclei of the basal ganglia, respectively. Light stimulation typically induced a triphasic response composed of early excitation, inhibition, and late excitation in GP/EPN neurons. Other response patterns lacking 1 or 2 of the components were also observed. The distribution of the cortical sites whose stimulation induced a triphasic response was confined, whereas stimulation of the large surrounding areas induced early and late excitation without inhibition. Our results suggest that cortical inputs to the GP/EPN are organized in a "local inhibitory and global excitatory" manner. Such organization seems to be the neuronal basis for information processing through the cortico-basal ganglia pathways, that is, releasing and terminating necessary information at an appropriate timing, while simultaneously suppressing other unnecessary information. © The Author 2017. Published by Oxford University Press.

  12. The posterior parietal cortex as integrative hub for whisker sensorimotor information

    NARCIS (Netherlands)

    Mohan, Hemanth; de Haan, Roel; Mansvelder, Huibert D; de Kock, Christiaan P J

    2018-01-01

    Our daily life consists of a continuous interplay between incoming sensory information and outgoing motor plans. Particularly during goal-directed behavior and active exploration of the sensory environment, brain circuits are merging sensory and motor signals. This is referred to as sensorimotor

  13. Picturing words? Sensorimotor cortex activation for printed words in child and adult readers

    Science.gov (United States)

    Dekker, Tessa M.; Mareschal, Denis; Johnson, Mark H.; Sereno, Martin I.

    2014-01-01

    Learning to read involves associating abstract visual shapes with familiar meanings. Embodiment theories suggest that word meaning is at least partially represented in distributed sensorimotor networks in the brain (Barsalou, 2008; Pulvermueller, 2013). We explored how reading comprehension develops by tracking when and how printed words start activating these “semantic” sensorimotor representations as children learn to read. Adults and children aged 7–10 years showed clear category-specific cortical specialization for tool versus animal pictures during a one-back categorisation task. Thus, sensorimotor representations for these categories were in place at all ages. However, co-activation of these same brain regions by the visual objects’ written names was only present in adults, even though all children could read and comprehend all presented words, showed adult-like task performance, and older children were proficient readers. It thus takes years of training and expert reading skill before spontaneous processing of printed words’ sensorimotor meanings develops in childhood. PMID:25463817

  14. Increasing CNS norepinephrine levels by the precursor L-DOPS facilitates beam-walking recovery after sensorimotor cortex ablation in rats.

    Science.gov (United States)

    Kikuchi, K; Nishino, K; Ohyu, H

    2000-03-31

    The present investigation was conducted to document a role of L-threo-3,4-dihydroxyphenylserine (L-DOPS), precursor of L-norepinephrine (NE), in the functional recovery from beam-walking performance deficits in rats after unilateral sensorimotor cortex ablation. L-DOPS was administered simultaneously with benserazide (BSZ; a peripheral aromatic amino acid decarboxylase inhibitor), and the regional contents of NE in the cerebral cortex, hippocampus, and cerebellum were assayed. Behavioral recovery was demonstrated by the rats treated with L-DOPS and BSZ, and the rate of recovery was significantly different from that of either BSZ-treated or vehicle-treated control rats. The NE tissue levels in the three discrete regions of the rat brain were significantly elevated in the experimental rats receiving both L-DOPS and BSZ. The present studies indicate that increasing NE levels by the precursor L-DOPS may be responsible for facilitating behavioral recovery from beam-walking performance deficits in rats, and further suggest that L-DOPS may become one of the candidate compounds for further clinical human trials promoting functional recovery after injuries to the cerebral cortex.

  15. Use-dependent dendritic regrowth is limited after unilateral controlled cortical impact to the forelimb sensorimotor cortex.

    Science.gov (United States)

    Jones, Theresa A; Liput, Daniel J; Maresh, Erin L; Donlan, Nicole; Parikh, Toral J; Marlowe, Dana; Kozlowski, Dorothy A

    2012-05-01

    Compensatory neural plasticity occurs in both hemispheres following unilateral cortical damage incurred by seizures, stroke, and focal lesions. Plasticity is thought to play a role in recovery of function, and is important for the utility of rehabilitation strategies. Such effects have not been well described in models of traumatic brain injury (TBI). We examined changes in immunoreactivity for neural structural and plasticity-relevant proteins in the area surrounding a controlled cortical impact (CCI) to the forelimb sensorimotor cortex (FL-SMC), and in the contralateral homotopic cortex over time (3-28 days). CCI resulted in considerable motor deficits in the forelimb contralateral to injury, and increased reliance on the ipsilateral forelimb. The density of dendritic processes, visualized with immunostaining for microtubule-associated protein-2 (MAP-2), were bilaterally decreased at all time points. Synaptophysin (SYN) immunoreactivity increased transiently in the injured hemisphere, but this reflected an atypical labeling pattern, and it was unchanged in the contralateral hemisphere compared to uninjured controls. The lack of compensatory neuronal structural plasticity in the contralateral homotopic cortex, despite behavioral asymmetries, is in contrast to previous findings in stroke models. In the cortex surrounding the injury (but not the contralateral cortex), decreases in dendrites were accompanied by neurodegeneration, as indicated by Fluoro-Jade B (FJB) staining, and increased expression of the growth-inhibitory protein Nogo-A. These studies indicate that, following unilateral CCI, the cortex undergoes neuronal structural degradation in both hemispheres out to 28 days post-injury, which may be indicative of compromised compensatory plasticity. This is likely to be an important consideration in designing therapeutic strategies aimed at enhancing plasticity following TBI.

  16. Plasticity in the sensorimotor cortex induced by Music-supported therapy in stroke patients: a TMS study.

    Science.gov (United States)

    Grau-Sánchez, Jennifer; Amengual, Julià L; Rojo, Nuria; Veciana de Las Heras, Misericordia; Montero, Jordi; Rubio, Francisco; Altenmüller, Eckart; Münte, Thomas F; Rodríguez-Fornells, Antoni

    2013-01-01

    Playing a musical instrument demands the engagement of different neural systems. Recent studies about the musician's brain and musical training highlight that this activity requires the close interaction between motor and somatosensory systems. Moreover, neuroplastic changes have been reported in motor-related areas after short and long-term musical training. Because of its capacity to promote neuroplastic changes, music has been used in the context of stroke neurorehabilitation. The majority of patients suffering from a stroke have motor impairments, preventing them to live independently. Thus, there is an increasing demand for effective restorative interventions for neurological deficits. Music-supported Therapy (MST) has been recently developed to restore motor deficits. We report data of a selected sample of stroke patients who have been enrolled in a MST program (1 month intense music learning). Prior to and after the therapy, patients were evaluated with different behavioral motor tests. Transcranial Magnetic Stimulation (TMS) was applied to evaluate changes in the sensorimotor representations underlying the motor gains observed. Several parameters of excitability of the motor cortex were assessed as well as the cortical somatotopic representation of a muscle in the affected hand. Our results revealed that participants obtained significant motor improvements in the paretic hand and those changes were accompanied by changes in the excitability of the motor cortex. Thus, MST leads to neuroplastic changes in the motor cortex of stroke patients which may explain its efficacy.

  17. Plasticity in the sensorimotor cortex induced by Music-supported therapy in stroke patients: A TMS study

    Directory of Open Access Journals (Sweden)

    Jennifer eGrau-Sánchez

    2013-09-01

    Full Text Available Playing a musical instrument demands the engagement of different neural systems. Recent studies about the musician’s brain and musical training highlight that this activity requires the close interaction between motor and somatosensory systems. Moreover, neuroplastic changes have been reported in motor-related areas after short and long-term musical training. Because of its capacity to promote neuroplastic changes, music has been used in the context of stroke neurorehabilitation. The majority of patients suffering from a stroke have motor impairments, preventing them to live independently. Thus, there is an increasing demand for effective restorative interventions for neurological deficits. Music-supported Therapy (MST has been recently developed to restore motor deficits. We report data of a selected sample of stroke patients who have been enrolled in a MST program (1 month intense music learning. Prior to and after the therapy, patients were evaluated with different behavioral motor tests. Transcranial Magnetic Stimulation (TMS was applied to evaluate changes in the sensorimotor representations underlying the motor gains observed. Several parameters of excitability of the motor cortex were assessed as well as the cortical somatotopic representation of a muscle in the affected hand. Our results revealed that participants obtained significant motor improvements in the paretic hand and those changes were accompanied by changes in the excitability of the motor cortex. Thus, MST leads to neuroplastic changes in the motor cortex of stroke patients which may explain its efficacy.

  18. Ladder beam and camera video recording system for evaluating forelimb and hindlimb deficits after sensorimotor cortex injury in rats.

    Science.gov (United States)

    Soblosky, J S; Colgin, L L; Chorney-Lane, D; Davidson, J F; Carey, M E

    1997-12-30

    Hindlimb and forelimb deficits in rats caused by sensorimotor cortex lesions are frequently tested by using the narrow flat beam (hindlimb), the narrow pegged beam (hindlimb and forelimb) or the grid-walking (forelimb) tests. Although these are excellent tests, the narrow flat beam generates non-parametric data so that using more powerful parametric statistical analyses are prohibited. All these tests can be difficult to score if the rat is moving rapidly. Foot misplacements, especially on the grid-walking test, are indicative of an ongoing deficit, but have not been reliably and accurately described and quantified previously. In this paper we present an easy to construct and use horizontal ladder-beam with a camera system on rails which can be used to evaluate both hindlimb and forelimb deficits in a single test. By slow motion videotape playback we were able to quantify and demonstrate foot misplacements which go beyond the recovery period usually seen using more conventional measures (i.e. footslips and footfaults). This convenient system provides a rapid and reliable method for recording and evaluating rat performance on any type of beam and may be useful for measuring sensorimotor recovery following brain injury.

  19. Overall biological activity of sensorimotor and visual brain cortex of rabbits with early neurological disorders induced by high doses of γ-radiation

    International Nuclear Information System (INIS)

    Silin, D.Ya.

    1988-01-01

    The overall bioelectrical activity of the sensorimotor and visual brain cortex of rabbits was estimated during early neurological impairment caused by 120 Gy gamma irradiation. The characteristic changes were revealed in the amplitude, form, energy spectrum and spatial biopotential synchronization. The changes in the bioelectrical activity of the brain were associated with the clinically displayed stages of the neurological process development

  20. Pattern of chondroitin sulfate proteoglycan expression after ablation of the sensorimotor cortex of the neonatal and adult rat brain

    Directory of Open Access Journals (Sweden)

    Dacić Sanja

    2008-01-01

    Full Text Available The central nervous system has a limited capacity for self-repair after damage. However, the neonatal brain has agreater capacity for recovery than the adult brain. These differences in the regenerative capability depend on local environmental factors and the maturational stage of growing axons. Among molecules which have both growth-promoting and growth-inhibiting activities is the heterogeneous class of chondroitin sulfate proteoglycans (CSPGs. In this paper, we investigated the chondroitin-4 and chondroitin-6 sulfate proteoglycan expression profile after left sensorimotor cortex ablation of the neonatal and adult rat brain. Immunohistochemical analysis revealed that compared to the normal uninjured cortex, lesion provoked up regulation of CSPGs showing a different pattern of expression in the neonatal vs. the adult brain. Punctuate and membrane-bound labeling was predominate after neonatal lesion, where as heavy deposition of staining in the extracellular matrix was observed after adult lesion. Heavy deposition of CSPG immunoreactivity around the lesionsite in adult rats, in contrast to a less CSPG-rich environment in neonatal rats, indicated that enhancement of the recovery process after neonatal injury is due to amore permissive environment.

  1. Functional activity of the sensorimotor cortex and cerebellum relates to cervical dystonia symptoms.

    Science.gov (United States)

    Burciu, Roxana G; Hess, Christopher W; Coombes, Stephen A; Ofori, Edward; Shukla, Priyank; Chung, Jae Woo; McFarland, Nikolaus R; Wagle Shukla, Aparna; Okun, Michael S; Vaillancourt, David E

    2017-09-01

    Cervical dystonia (CD) is the most common type of focal dystonia, causing abnormal movements of the neck and head. In this study, we used noninvasive imaging to investigate the motor system of patients with CD and uncover the neural correlates of dystonic symptoms. Furthermore, we examined whether a commonly prescribed anticholinergic medication in CD has an effect on the dystonia-related brain abnormalities. Participants included 16 patients with CD and 16 healthy age-matched controls. We collected functional MRI scans during a force task previously shown to extensively engage the motor system, and diffusion and T1-weighted MRI scans from which we calculated free-water and brain tissue densities. The dystonia group was also scanned ca. 2 h after a 2-mg dose of trihexyphenidyl. Severity of dystonia was assessed pre- and post-drug using the Burke-Fahn-Marsden Dystonia Rating Scale. Motor-related activity in CD was altered relative to controls in the primary somatosensory cortex, cerebellum, dorsal premotor and posterior parietal cortices, and occipital cortex. Most importantly, a regression model showed that increased severity of symptoms was associated with decreased functional activity of the somatosensory cortex and increased activity of the cerebellum. Structural imaging measures did not differ between CD and controls. The single dose of trihexyphenidyl altered the fMRI signal in the somatosensory cortex but not in the cerebellum. Symptom severity was not significantly reduced post-treatment. Findings show widespread changes in functional brain activity in CD and most importantly that dystonic symptoms relate to disrupted activity in the somatosensory cortex and cerebellum. Hum Brain Mapp 38:4563-4573, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  2. The contribution of the human posterior parietal cortex to episodic memory

    OpenAIRE

    Sestieri, Carlo; Shulman, Gordon L.; Corbetta, Maurizio

    2017-01-01

    The posterior parietal cortex (PPC) is traditionally associated with attention, perceptual decision making and sensorimotor transformations, but more recent human neuroimaging studies support an additional role in episodic memory retrieval. In this Opinion article, we present a functional–anatomical model of the involvement of the PPC in memory retrieval. Parietal regions involved in perceptual attention and episodic memory are largely segregated and often show a push–pull relationship, poten...

  3. Hypoactivation of the primary sensorimotor cortex in de novo Parkinson's disease. A motor fMRI study under controlled conditions

    International Nuclear Information System (INIS)

    Tessa, Carlo; Vignali, Claudio; Lucetti, Claudio; Diciotti, Stefano; Paoli, Lorenzo; Ginestroni, Andrea; Mascalchi, Mario; Cecchi, Paolo; Baldacci, Filippo; Giannelli, Marco; Bonuccelli, Ubaldo

    2012-01-01

    Nuclear medicine studies in Parkinson's disease (PD) indicate that nigrostriatal damage causes a widespread cortical hypoactivity assumed to be due to reduced excitatory thalamic outflow. However, so far, functional MRI (fMRI) studies have provided controversial data about this ''functional deafferentation'' phenomenon. To further clarify this issue, we assessed, with fMRI, de novo drug-naive PD patients using a relatively complex motor task under strictly controlled conditions. Nineteen de novo PD patients with right-predominant or bilateral symptoms and 13 age-matched healthy volunteers performed continuous writing of ''8'' figures with the right-dominant hand using a MR-compatible device that enables identification of incorrectly performed tasks and measures the size and the frequency of the ''8''s. The data were analyzed with FSL software and correlated with the clinical severity rated according to the Hoehn and Yahr (HY) staging system. Fifteen (89%) of 19 PD patients and 12 (92%) of 13 controls correctly executed the task. PD patients showed significant hypoactivation of the left primary sensorimotor cortex (SM1) and cerebellum and no hyperactive areas as compared to controls. However, activation in SM1 and supplementary motor area bilaterally, in left supramarginal, parietal inferior, parietal superior and frontal superior gyri as well as in right parietal superior and angular gyri paralleled increasing disease severity as assessed with the HY stage. In line with the ''deafferentation hypothesis'', fMRI demonstrates hypoactivation of the SM1 in the early clinical stage of PD. (orig.)

  4. Disorganization of Oligodendrocyte Development in the Layer II/III of the Sensorimotor Cortex Causes Motor Coordination Dysfunction in a Model of White Matter Injury in Neonatal Rats.

    Science.gov (United States)

    Ueda, Yoshitomo; Misumi, Sachiyo; Suzuki, Mina; Ogawa, Shino; Nishigaki, Ruriko; Ishida, Akimasa; Jung, Cha-Gyun; Hida, Hideki

    2018-01-01

    We previously established neonatal white matter injury (WMI) model rat that is made by right common carotid artery dissection at postnatal day 3, followed by 6% hypoxia for 60 min. This model has fewer oligodendrocyte progenitor cells and reduced myelin basic protein (MBP) positive areas in the sensorimotor cortex, but shows no apparent neuronal loss. However, how motor deficits are induced in this model is unclear. To elucidate the relationship between myelination disturbance and concomitant motor deficits, we first performed motor function tests (gait analysis, grip test, horizontal ladder test) and then analyzed myelination patterns in the sensorimotor cortex using transmission electron microscopy (TEM) and Contactin associated protein 1 (Caspr) staining in the neonatal WMI rats in adulthood. Behavioral tests revealed imbalanced motor coordination in this model. Motor deficit scores were higher in the neonatal WMI model, while hindlimb ladder stepping scores and forelimb grasping force were comparable to controls. Prolonged forelimb swing times and decreased hindlimb paw angles on the injured side were revealed by gait analysis. TEM revealed no change in myelinated axon number and the area g-ratio in the layer II/III of the cortex. Electromyographical durations and latencies in the gluteus maximus in response to electrical stimulation of the brain area were unchanged in the model. Caspr staining revealed fewer positive dots in layers II/III of the WMI cortex, indicating fewer and/or longer myelin sheath. These data suggest that disorganization of oligodendrocyte development in layers II/III of the sensorimotor cortex relates to imbalanced motor coordination in the neonatal WMI model rat.

  5. Sensorimotor cortex as a critical component of an 'extended' mirror neuron system: Does it solve the development, correspondence, and control problems in mirroring?

    Directory of Open Access Journals (Sweden)

    Pineda Jaime A

    2008-10-01

    ?" In this review, we argue from an anatomical, physiological, modeling, and functional perspectives that a critical component of the human mirror neuron system is sensorimotor cortex. Not only are sensorimotor transformations necessary for computing the patterns of muscle activation and kinematics during action observation but they provide potential answers to the development, correspondence and control problems.

  6. Sensorimotor cortex as a critical component of an 'extended' mirror neuron system: Does it solve the development, correspondence, and control problems in mirroring?

    Science.gov (United States)

    Pineda, Jaime A

    2008-01-01

    from an anatomical, physiological, modeling, and functional perspectives that a critical component of the human mirror neuron system is sensorimotor cortex. Not only are sensorimotor transformations necessary for computing the patterns of muscle activation and kinematics during action observation but they provide potential answers to the development, correspondence and control problems. PMID:18928566

  7. Physical and neural entrainment to rhythm: human sensorimotor coordination across tasks and effector systems

    Directory of Open Access Journals (Sweden)

    Jessica Marie Ross

    2014-08-01

    Full Text Available The human sensorimotor system can be readily entrained to environmental rhythms, through multiple sensory modalities. In this review, we provide an overview of theories of timekeeping that make this neuroentrainment possible. First, we present recent evidence that contests the assumptions made in classic timekeeper models. The role of state estimation, sensory feedback and movement parameters on the organization of sensorimotor timing are discussed in the context of recent experiments that examined simultaneous timing and force control. This discussion is extended to the study of coordinated multi-effector movements and how they may be entrained.

  8. Human-Inspired Eigenmovement Concept Provides Coupling-Free Sensorimotor Control in Humanoid Robot

    Czech Academy of Sciences Publication Activity Database

    Alexandrov, A.V.; Lippi, V.; Mergner, T.; Frolov, A. A.; Hettich, G.; Húsek, Dušan

    2017-01-01

    Roč. 11, 25 April (2017), č. článku 22. ISSN 1662-5188 Institutional support: RVO:67985807 Keywords : human sensorimotor system * neuromechanics * biorobotics * motor control * eigenmovements Subject RIV: JD - Computer Applications, Robotics OBOR OECD: Robotics and automatic control Impact factor: 1.821, year: 2016

  9. Functional segregation of the human cingulate cortex is confirmed by functional connectivity based neuroanatomical parcellation.

    Science.gov (United States)

    Yu, Chunshui; Zhou, Yuan; Liu, Yong; Jiang, Tianzi; Dong, Haiwei; Zhang, Yunting; Walter, Martin

    2011-02-14

    The four-region model with 7 specified subregions represents a theoretical construct of functionally segregated divisions of the cingulate cortex based on integrated neurobiological assessments. Under this framework, we aimed to investigate the functional specialization of the human cingulate cortex by analyzing the resting-state functional connectivity (FC) of each subregion from a network perspective. In 20 healthy subjects we systematically investigated the FC patterns of the bilateral subgenual (sACC) and pregenual (pACC) anterior cingulate cortices, anterior (aMCC) and posterior (pMCC) midcingulate cortices, dorsal (dPCC) and ventral (vPCC) posterior cingulate cortices and retrosplenial cortices (RSC). We found that each cingulate subregion was specifically integrated in the predescribed functional networks and showed anti-correlated resting-state fluctuations. The sACC and pACC were involved in an affective network and anti-correlated with the sensorimotor and cognitive networks, while the pACC also correlated with the default-mode network and anti-correlated with the visual network. In the midcingulate cortex, however, the aMCC was correlated with the cognitive and sensorimotor networks and anti-correlated with the visual, affective and default-mode networks, whereas the pMCC only correlated with the sensorimotor network and anti-correlated with the cognitive and visual networks. The dPCC and vPCC involved in the default-mode network and anti-correlated with the sensorimotor, cognitive and visual networks, in contrast, the RSC was mainly correlated with the PCC and thalamus. Based on a strong hypothesis driven approach of anatomical partitions of the cingulate cortex, we could confirm their segregation in terms of functional neuroanatomy, as suggested earlier by task studies or exploratory multi-seed investigations. Copyright © 2010 Elsevier Inc. All rights reserved.

  10. Functional imaging of the sensorimotor cortex using an ultra-fast MR imaging method

    International Nuclear Information System (INIS)

    Tsunoda, Akira; Nakajima, Yasoichi; Sato, Kiyoshi; Katayama, Jin; Machida, Yoshio; Nozaki, Seiji; Makita, Jun-ichi.

    1996-01-01

    The aim of this study was to assess changes in brain activity during a motor task and variable sensory stimulation using echo planar imaging, which represents the fastest clinically useful imaging technique available. The subjects of this study were 11 healthy volunteers, 4 males and 11 females, with an average of 26.4 years. The subjects were instructed to tap the fingers of one hand as the motor task. Compressed air was applied 5 times a second as 'simple' sensory stimulation. Simple figures were drawn on the subjects palm as 'complex' sensory stimulation. In all cases, functional imaging was performed by T 2 * -weighted echo planar imaging (TE=53 msec, TR=3000 msec, flip angle=90 degrees, matrix 64 x 64, FOV=205 mm, slice thickness=8 mm) alternately at rest and during the task (intervals: 30 sec). A total of 60 images was collected in 3 minutes. Images obtained by subtracting images at rest and during the task were analyzed. Almost all subjects showed a transient signal increase in the contralateral paracentral region during simple sensory stimulation. Continuous signal increases in the contra- and/or ipsi-lateral para-central region were observed durirg complex sensory stimulation. Some exhibited signal increases in the parietal or frontal association cortex, but they disappeared when subject's attention was distracted during stimulation. All subjects displayed signal increases in the contralateral para-central region during the motor task. Some of them exhibited signal increases in the medial frontal area (supplementary motor area) and ipsilateral para-central region. These results suggest that the signal increases of functional MRI reflect not only simple reactions to stimulation but higher cerebral function as well. (J.P.N.)

  11. Functional Laterality of Task-Evoked Activation in Sensorimotor Cortex of Preterm Infants: An Optimized 3 T fMRI Study Employing a Customized Neonatal Head Coil.

    Science.gov (United States)

    Scheef, Lukas; Nordmeyer-Massner, Jurek A; Smith-Collins, Adam Pr; Müller, Nicole; Stegmann-Woessner, Gaby; Jankowski, Jacob; Gieseke, Jürgen; Born, Mark; Seitz, Hermann; Bartmann, Peter; Schild, Hans H; Pruessmann, Klaas P; Heep, Axel; Boecker, Henning

    2017-01-01

    Functional magnetic resonance imaging (fMRI) in neonates has been introduced as a non-invasive method for studying sensorimotor processing in the developing brain. However, previous neonatal studies have delivered conflicting results regarding localization, lateralization, and directionality of blood oxygenation level dependent (BOLD) responses in sensorimotor cortex (SMC). Amongst the confounding factors in interpreting neonatal fMRI studies include the use of standard adult MR-coils providing insufficient signal to noise, and liberal statistical thresholds, compromising clinical interpretation at the single subject level. Here, we employed a custom-designed neonatal MR-coil adapted and optimized to the head size of a newborn in order to improve robustness, reliability and validity of neonatal sensorimotor fMRI. Thirteen preterm infants with a median gestational age of 26 weeks were scanned at term-corrected age using a prototype 8-channel neonatal head coil at 3T (Achieva, Philips, Best, NL). Sensorimotor stimulation was elicited by passive extension/flexion of the elbow at 1 Hz in a block design. Analysis of temporal signal to noise ratio (tSNR) was performed on the whole brain and the SMC, and was compared to data acquired with an 'adult' 8 channel head coil published previously. Task-evoked activation was determined by single-subject SPM8 analyses, thresholded at p lateralization of SMC activation, as found in children and adults, is already present in the newborn period.

  12. Sensorimotor cortex ablation induces time-dependent response of ACTH cells in adult rats: behavioral, immunohistomorphometric and hormonal study.

    Science.gov (United States)

    Lavrnja, Irena; Trifunovic, Svetlana; Ajdzanovic, Vladimir; Pekovic, Sanja; Bjelobaba, Ivana; Stojiljkovic, Mirjana; Milosevic, Verica

    2014-02-10

    Traumatic brain injury (TBI) represents a serious event with far reaching complications, including pituitary dysfunction. Pars distalis corticotropes (ACTH cells), that represent the active module of hypothalamo-pituitary-adrenocortical axis, seem to be affected as well. Since pituitary failure after TBI has been associated with neurobehavioral impairments the aim of this study was to evaluate the effects of TBI on recovery of motor functions, morphology and secretory activity of ACTH cells in the pituitary of adult rats. Wistar male rats, initially exposed to sensorimotor cortex ablation (SCA), were sacrificed at the 2nd, 7th, 14th and 30th days post-surgery (dps). A beam walking test was used to evaluate the recovery of motor functions. Pituitary glands and blood were collected for morphological and hormonal analyses. During the first two weeks post-injury increased recovery of locomotor function was detected, reaching almost the control value at day 30. SCA induces significant increase of pituitary weights compared to their time-matched controls. The volume of ACTH-immunopositive cells was reduced at the 7th dps, while at the 14th dps their volume was enlarged, in comparison to corresponding sham controls. Volume density of ACTH cells was increased only at 14th dps, while at day 30 this increase was insignificant. The plasma level of ACTH transiently increased after the injury. The most pronounced changes were observed at the 7th and 14th dps, and were followed by decrease toward control levels at the 30th dps. Thus, temporal changes in the hypothalamic-pituitary-adrenal axis after traumatic brain injury appear to correlate with the recovery process. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Increased low-frequency oscillation amplitude of sensorimotor cortex associated with the severity of structural impairment in cervical myelopathy.

    Directory of Open Access Journals (Sweden)

    Fuqing Zhou

    Full Text Available Decreases in metabolites and increased motor-related, but decreased sensory-related activation of the sensorimotor cortex (SMC have been observed in patients with cervical myelopathy (CM using advanced MRI techniques. However, the nature of intrinsic neuronal activity in the SMC, and the relationship between cerebral function and structural damage of the spinal cord in patients with CM are not fully understood. The purpose of this study was to assess intrinsic neuronal activity by calculating the regional amplitude of low frequency fluctuations (ALFF using resting-state functional MRI (rs-fMRI, and correlations with clinical and imaging indices. Nineteen patients and 19 age- and sex-matched healthy subjects underwent rs-fMRI scans. ALFF measurements were performed in the SMC, a key brain network likely to impaired or reorganized patients with CM. Compared with healthy subjects, increased amplitude of cortical low-frequency oscillations (LFO was observed in the right precentral gyrus, right postcentral gyrus, and left supplementary motor area. Furthermore, increased z-ALFF values in the right precentral gyrus and right postcentral gyrus correlated with decreased fractional anisotropy values at the C2 level, which indicated increased intrinsic neuronal activity in the SMC corresponding to the structural impairment in the spinal cord of patients with CM. These findings suggest a complex and diverging relationship of cortical functional reorganization and distal spinal anatomical compression in patients with CM and, thus, add important information in understanding how spinal cord integrity may be a factor in the intrinsic covariance of spontaneous low-frequency fluctuations of BOLD signals involved in cortical plasticity.

  14. Contribution of the resting-state functional connectivity of the contralesional primary sensorimotor cortex to motor recovery after subcortical stroke.

    Directory of Open Access Journals (Sweden)

    Huijuan Xu

    Full Text Available It remains uncertain if the contralesional primary sensorimotor cortex (CL_PSMC contributes to motor recovery after stroke. Here we investigated longitudinal changes in the resting-state functional connectivity (rsFC of the CL_PSMC and their association with motor recovery. Thirteen patients who had experienced subcortical stroke underwent a series of resting-state fMRI and clinical assessments over a period of 1 year at 5 time points, i.e., within the first week, at 2 weeks, 1 month, 3 months, and 1 year after stroke onset. Thirteen age- and gender-matched healthy subjects were recruited as controls. The CL_PSMC was defined as a region centered at the voxel that had greatest activation during hand motion task. The dynamic changes in the rsFCs of the CL_PSMC within the whole brain were evaluated and correlated with the Motricity Index (MI scores. Compared with healthy controls, the rsFCs of the CL_PSMC with the bilateral PSMC were initially decreased, then gradually increased, and finally restored to the normal level 1 year later. Moreover, the dynamic change in the inter-hemispheric rsFC between the bilateral PSMC in these patients was positively correlated with the MI scores. However, the intra-hemispheric rsFC of the CL_PSMC was not correlated with the MI scores. This study shows dynamic changes in the rsFCs of the CL_PSMC after stroke and suggests that the increased inter-hemispheric rsFC between the bilateral PSMC may facilitate motor recovery in stroke patients. However, generalization of our findings is limited by the small sample size of our study and needs to be confirmed.

  15. Approach motivation in human cerebral cortex

    OpenAIRE

    Casasanto, Daniel; Brookshire, Geoffrey

    2018-01-01

    Different regions of the human cerebral cortex are specialized for different emotions, but the principles underlying this specialization have remained unknown. According to the sword and shield hypothesis, hemispheric specialization for affective motivation, a basic dimension of human emotion, varies across individuals according to the way they use their hands to perform approach- and avoidance-related actions. In a test of this hypothesis, here we measured approach motivation before and afte...

  16. Task-related activity in sensorimotor cortex in Parkinson’s disease and essential tremor: changes in beta and gamma bands

    Directory of Open Access Journals (Sweden)

    Nathan C Rowland

    2015-09-01

    Full Text Available In Parkinson’s disease patients in the OFF medication state, basal ganglia local field potentials exhibit changes in beta and gamma oscillations that correlate with reduced voluntary movement, manifested as rigidity and akinesia. However, magnetoencephalography and low-resolution electrocorticography (ECoG studies in Parkinson’s patients suggest that changes in sensorimotor cortical oscillations differ from those of the basal ganglia. To more clearly define the role of sensorimotor cortex oscillatory activity in Parkinson’s, we performed intraoperative, high-resolution (4 mm spacing ECoG recordings in 10 Parkinson’s patients (2 females, ages 47-72 undergoing deep brain stimulation (DBS lead placement in the awake, OFF medication state. We analyzed ECoG potentials during a computer-controlled reaching task designed to separate movement preparation from movement execution and compared findings to similar invasive recordings in eight patients with essential tremor (3 females, ages 59-78, a condition not associated with rigidity or akinesia. We show that 1 cortical beta spectral power at rest does not differ between Parkinson’s and essential tremor patients (p = 0.85, 2 early motor preparation in Parkinson’s patients in the OFF medication state is associated with a larger beta desynchronization compared to patients with essential tremor (p = 0.0061, and 3 cortical broadband gamma power is elevated in Parkinson’s patients compared to essential tremor patients during both rest and task recordings (p = 0.004. Our findings suggest an oscillatory profile in sensorimotor cortex of Parkinson’s patients that, in contrast to the basal ganglia, may act to promote movement to oppose the anti-kinetic bias of the dopamine-depleted state.

  17. The contribution of the human posterior parietal cortex to episodic memory.

    Science.gov (United States)

    Sestieri, Carlo; Shulman, Gordon L; Corbetta, Maurizio

    2017-02-17

    The posterior parietal cortex (PPC) is traditionally associated with attention, perceptual decision making and sensorimotor transformations, but more recent human neuroimaging studies support an additional role in episodic memory retrieval. In this Opinion article, we present a functional-anatomical model of the involvement of the PPC in memory retrieval. Parietal regions involved in perceptual attention and episodic memory are largely segregated and often show a push-pull relationship, potentially mediated by prefrontal regions. Moreover, different PPC regions carry out specific functions during retrieval - for example, representing retrieved information, recoding this information based on task demands, or accumulating evidence for memory decisions.

  18. Uncovering a context-specific connectional fingerprint of human dorsal premotor cortex

    DEFF Research Database (Denmark)

    Moisa, Marius; Siebner, Hartwig R; Pohmann, Rolf

    2012-01-01

    Primate electrophysiological and lesion studies indicate a prominent role of the left dorsal premotor cortex (PMd) in action selection based on learned sensorimotor associations. Here we applied transcranial magnetic stimulation (TMS) to human left PMd at low or high intensity while right...... to directly assess how stimulation of left PMd modulates task-related brain activity depending on the mode of movement selection. Relative to passive viewing, both tasks activated a frontoparietal motor network. Compared with low-intensity TMS, high-intensity TMS of left PMd was associated with an increase...

  19. Maps of space in human frontoparietal cortex.

    Science.gov (United States)

    Jerde, Trenton A; Curtis, Clayton E

    2013-12-01

    Prefrontal cortex (PFC) and posterior parietal cortex (PPC) are neural substrates for spatial cognition. We here review studies in which we tested the hypothesis that human frontoparietal cortex may function as a priority map. According to priority map theory, objects or locations in the visual world are represented by neural activity that is proportional to their attentional priority. Using functional magnetic resonance imaging (fMRI), we first identified topographic maps in PFC and PPC as candidate priority maps of space. We then measured fMRI activity in candidate priority maps during the delay periods of a covert attention task, a spatial working memory task, and a motor planning task to test whether the activity depended on the particular spatial cognition. Our hypothesis was that some, but not all, candidate priority maps in PFC and PPC would be agnostic with regard to what was being prioritized, in that their activity would reflect the location in space across tasks rather than a particular kind of spatial cognition (e.g., covert attention). To test whether patterns of delay period activity were interchangeable during the spatial cognitive tasks, we used multivariate classifiers. We found that decoders trained to predict the locations on one task (e.g., working memory) cross-predicted the locations on the other tasks (e.g., covert attention and motor planning) in superior precentral sulcus (sPCS) and in a region of intraparietal sulcus (IPS2), suggesting that these patterns of maintenance activity may be interchangeable across the tasks. Such properties make sPCS in frontal cortex and IPS2 in parietal cortex viable priority map candidates, and suggest that these areas may be the human homologs of the monkey frontal eye field (FEF) and lateral intraparietal area (LIP). Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Dissociation of object and spatial visual processing pathways in human extrastriate cortex

    Energy Technology Data Exchange (ETDEWEB)

    Haxby, J.V.; Grady, C.L.; Horwitz, B.; Ungerleider, L.G.; Mishkin, M.; Carson, R.E.; Herscovitch, P.; Schapiro, M.B.; Rapoport, S.I. (National Institutes of Health, Bethesda, MD (USA))

    1991-03-01

    The existence and neuroanatomical locations of separate extrastriate visual pathways for object recognition and spatial localization were investigated in healthy young men. Regional cerebral blood flow was measured by positron emission tomography and bolus injections of H2(15)O, while subjects performed face matching, dot-location matching, or sensorimotor control tasks. Both visual matching tasks activated lateral occipital cortex. Face discrimination alone activated a region of occipitotemporal cortex that was anterior and inferior to the occipital area activated by both tasks. The spatial location task alone activated a region of lateral superior parietal cortex. Perisylvian and anterior temporal cortices were not activated by either task. These results demonstrate the existence of three functionally dissociable regions of human visual extrastriate cortex. The ventral and dorsal locations of the regions specialized for object recognition and spatial localization, respectively, suggest some homology between human and nonhuman primate extrastriate cortex, with displacement in human brain, possibly related to the evolution of phylogenetically newer cortical areas.

  1. Functional Laterality of Task-Evoked Activation in Sensorimotor Cortex of Preterm Infants: An Optimized 3 T fMRI Study Employing a Customized Neonatal Head Coil.

    Directory of Open Access Journals (Sweden)

    Lukas Scheef

    Full Text Available Functional magnetic resonance imaging (fMRI in neonates has been introduced as a non-invasive method for studying sensorimotor processing in the developing brain. However, previous neonatal studies have delivered conflicting results regarding localization, lateralization, and directionality of blood oxygenation level dependent (BOLD responses in sensorimotor cortex (SMC. Amongst the confounding factors in interpreting neonatal fMRI studies include the use of standard adult MR-coils providing insufficient signal to noise, and liberal statistical thresholds, compromising clinical interpretation at the single subject level.Here, we employed a custom-designed neonatal MR-coil adapted and optimized to the head size of a newborn in order to improve robustness, reliability and validity of neonatal sensorimotor fMRI. Thirteen preterm infants with a median gestational age of 26 weeks were scanned at term-corrected age using a prototype 8-channel neonatal head coil at 3T (Achieva, Philips, Best, NL. Sensorimotor stimulation was elicited by passive extension/flexion of the elbow at 1 Hz in a block design. Analysis of temporal signal to noise ratio (tSNR was performed on the whole brain and the SMC, and was compared to data acquired with an 'adult' 8 channel head coil published previously. Task-evoked activation was determined by single-subject SPM8 analyses, thresholded at p < 0.05, whole-brain FWE-corrected.Using a custom-designed neonatal MR-coil, we found significant positive BOLD responses in contralateral SMC after unilateral passive sensorimotor stimulation in all neonates (analyses restricted to artifact-free data sets = 8/13. Improved imaging characteristics of the neonatal MR-coil were evidenced by additional phantom and in vivo tSNR measurements: phantom studies revealed a 240% global increase in tSNR; in vivo studies revealed a 73% global and a 55% local (SMC increase in tSNR, as compared to the 'adult' MR-coil.Our findings strengthen the

  2. Amodal processing in human prefrontal cortex.

    Science.gov (United States)

    Tamber-Rosenau, Benjamin J; Dux, Paul E; Tombu, Michael N; Asplund, Christopher L; Marois, René

    2013-07-10

    Information enters the cortex via modality-specific sensory regions, whereas actions are produced by modality-specific motor regions. Intervening central stages of information processing map sensation to behavior. Humans perform this central processing in a flexible, abstract manner such that sensory information in any modality can lead to response via any motor system. Cognitive theories account for such flexible behavior by positing amodal central information processing (e.g., "central executive," Baddeley and Hitch, 1974; "supervisory attentional system," Norman and Shallice, 1986; "response selection bottleneck," Pashler, 1994). However, the extent to which brain regions embodying central mechanisms of information processing are amodal remains unclear. Here we apply multivariate pattern analysis to functional magnetic resonance imaging (fMRI) data to compare response selection, a cognitive process widely believed to recruit an amodal central resource across sensory and motor modalities. We show that most frontal and parietal cortical areas known to activate across a wide variety of tasks code modality, casting doubt on the notion that these regions embody a central processor devoid of modality representation. Importantly, regions of anterior insula and dorsolateral prefrontal cortex consistently failed to code modality across four experiments. However, these areas code at least one other task dimension, process (instantiated as response selection vs response execution), ensuring that failure to find coding of modality is not driven by insensitivity of multivariate pattern analysis in these regions. We conclude that abstract encoding of information modality is primarily a property of subregions of the prefrontal cortex.

  3. Long-range memory and non-Markov statistical effects in human sensorimotor coordination

    Science.gov (United States)

    M. Yulmetyev, Renat; Emelyanova, Natalya; Hänggi, Peter; Gafarov, Fail; Prokhorov, Alexander

    2002-12-01

    In this paper, the non-Markov statistical processes and long-range memory effects in human sensorimotor coordination are investigated. The theoretical basis of this study is the statistical theory of non-stationary discrete non-Markov processes in complex systems (Phys. Rev. E 62, 6178 (2000)). The human sensorimotor coordination was experimentally studied by means of standard dynamical tapping test on the group of 32 young peoples with tap numbers up to 400. This test was carried out separately for the right and the left hand according to the degree of domination of each brain hemisphere. The numerical analysis of the experimental results was made with the help of power spectra of the initial time correlation function, the memory functions of low orders and the first three points of the statistical spectrum of non-Markovity parameter. Our observations demonstrate, that with the regard to results of the standard dynamic tapping-test it is possible to divide all examinees into five different dynamic types. We have introduced the conflict coefficient to estimate quantitatively the order-disorder effects underlying life systems. The last one reflects the existence of disbalance between the nervous and the motor human coordination. The suggested classification of the neurophysiological activity represents the dynamic generalization of the well-known neuropsychological types and provides the new approach in a modern neuropsychology.

  4. Centre-surround organization of fast sensorimotor integration in human motor hand area

    DEFF Research Database (Denmark)

    Dubbioso, Raffaele; Raffin, Estelle; Karabanov, Anke

    2017-01-01

    Using the short-latency afferent inhibition (SAI) paradigm, transcranial magnetic stimulation (TMS) of the primary motor hand area (M1HAND) can probe how sensory input from limbs modulates corticomotor output in humans. Here we applied a novel TMS mapping approach to chart the spatial representat......Using the short-latency afferent inhibition (SAI) paradigm, transcranial magnetic stimulation (TMS) of the primary motor hand area (M1HAND) can probe how sensory input from limbs modulates corticomotor output in humans. Here we applied a novel TMS mapping approach to chart the spatial...... in M1HAND. Like homotopic SAI, heterotopic SAF was somatotopically expressed in M1HAND. Together, the results provide first-time evidence that fast sensorimotor integration involves centre-inhibition and surround-facilitation in human M1HAND....

  5. Frequency specific modulation of human somatosensory cortex

    Directory of Open Access Journals (Sweden)

    Matteo eFeurra

    2011-02-01

    Full Text Available Oscillatory neuronal activities are commonly observed in response to sensory stimulation. However, their functional roles are still the subject of debate. One way to probe the roles of oscillatory neural activities is to deliver alternating current to the cortex at biologically relevant frequencies and examine whether such stimulation influences perception and cognition. In this study, we tested whether transcranial alternating current stimulation (tACS over the primary somatosensory cortex (SI could elicit tactile sensations in humans in a frequency dependent manner. We tested the effectiveness of tACS over SI at frequency bands ranging from 2 to 70 Hz. Our results show that stimulation in alpha (10-14 Hz and high gamma (52-70 Hz frequency range produces a tactile sensation in the contralateral hand. A weaker effect was also observed for beta (16-20 Hz stimulation. These findings highlight the frequency-dependency of effective tACS over SI with the effective frequencies corresponding to those observed in previous EEG/MEG studies of tactile perception. Our present study suggests that tACS could be used as a powerful online stimulation technique to reveal the causal roles of oscillatory brain activities.

  6. Fluoro-Jade and TUNEL staining as useful tools to identify ischemic brain damage following moderate extradural compression of sensorimotor cortex.

    Science.gov (United States)

    Kundrotiene, Jurgita; Wägner, Anna; Liljequist, Sture

    2004-01-01

    Cerebral ischemia was produced by moderate compression for 30 min of a specific brain area in the sensorimotor cortex of Sprague-Dawley rats. On day 1, that is 24 h after the transient sensorimotor compression, ischemia-exposed animals displayed a marked focal neurological deficit documented as impaired beam walking performance. This functional disturbance was mainly due to contralateral fore- and hind-limb paresis. As assessed by daily beam walking tests it was shown that there was a spontaneous recovery of motor functions over a period of five to seven days after the ischemic event. Using histopathological analysis (Nissl staining) we have previously reported that the present experimental paradigm does not produce pannecrosis (tissue cavitation) despite the highly reproducible focal neurological deficit. We now show how staining with fluorescent markers for neuronal death, that is Fluoro-Jade and TUNEL, respectively, identifies regional patterns of selective neuronal death. These observations add further support to the working hypothesis that the brain damage caused by cortical compression-induced ischemia consists of scattered, degenerating neurons in specific brain regions. Postsurgical administration of the AMPA receptor specific antagonist, LY326325 (30 mg/kg; i.p., 70 min after compression), not only improved beam walking performance on day 1 to 3, respectively but also significantly reduced the number of Fluoro-Jade stained neurons on day 5. These results suggest that enhanced AMPA/glutamate receptor activity is at least partially responsible for the ischemia-produced brain damage detected by the fluorescent marker Fluoro-Jade.

  7. Human-Inspired Eigenmovement Concept Provides Coupling-Free Sensorimotor Control in Humanoid Robot.

    Science.gov (United States)

    Alexandrov, Alexei V; Lippi, Vittorio; Mergner, Thomas; Frolov, Alexander A; Hettich, Georg; Husek, Dusan

    2017-01-01

    Control of a multi-body system in both robots and humans may face the problem of destabilizing dynamic coupling effects arising between linked body segments. The state of the art solutions in robotics are full state feedback controllers. For human hip-ankle coordination, a more parsimonious and theoretically stable alternative to the robotics solution has been suggested in terms of the Eigenmovement (EM) control. Eigenmovements are kinematic synergies designed to describe the multi DoF system, and its control, with a set of independent, and hence coupling-free , scalar equations. This paper investigates whether the EM alternative shows "real-world robustness" against noisy and inaccurate sensors, mechanical non-linearities such as dead zones, and human-like feedback time delays when controlling hip-ankle movements of a balancing humanoid robot. The EM concept and the EM controller are introduced, the robot's dynamics are identified using a biomechanical approach, and robot tests are performed in a human posture control laboratory. The tests show that the EM controller provides stable control of the robot with proactive ("voluntary") movements and reactive balancing of stance during support surface tilts and translations. Although a preliminary robot-human comparison reveals similarities and differences, we conclude (i) the Eigenmovement concept is a valid candidate when different concepts of human sensorimotor control are considered, and (ii) that human-inspired robot experiments may help to decide in future the choice among the candidates and to improve the design of humanoid robots and robotic rehabilitation devices.

  8. Human sensorimotor communication: a theory of signaling in online social interactions.

    Science.gov (United States)

    Pezzulo, Giovanni; Donnarumma, Francesco; Dindo, Haris

    2013-01-01

    Although the importance of communication is recognized in several disciplines, it is rarely studied in the context of online social interactions and joint actions. During online joint actions, language and gesture are often insufficient and humans typically use non-verbal, sensorimotor forms of communication to send coordination signals. For example, when playing volleyball, an athlete can exaggerate her movements to signal her intentions to her teammates (say, a pass to the right) or to feint an adversary. Similarly, a person who is transporting a table together with a co-actor can push the table in a certain direction to signal where and when he intends to place it. Other examples of "signaling" are over-articulating in noisy environments and over-emphasizing vowels in child-directed speech. In all these examples, humans intentionally modify their action kinematics to make their goals easier to disambiguate. At the moment no formal theory exists of these forms of sensorimotor communication and signaling. We present one such theory that describes signaling as a combination of a pragmatic and a communicative action, and explains how it simplifies coordination in online social interactions. We cast signaling within a "joint action optimization" framework in which co-actors optimize the success of their interaction and joint goals rather than only their part of the joint action. The decision of whether and how much to signal requires solving a trade-off between the costs of modifying one's behavior and the benefits in terms of interaction success. Signaling is thus an intentional strategy that supports social interactions; it acts in concert with automatic mechanisms of resonance, prediction, and imitation, especially when the context makes actions and intentions ambiguous and difficult to read. Our theory suggests that communication dynamics should be studied within theories of coordination and interaction rather than only in terms of the maximization of information

  9. Human sensorimotor communication: a theory of signaling in online social interactions.

    Directory of Open Access Journals (Sweden)

    Giovanni Pezzulo

    Full Text Available Although the importance of communication is recognized in several disciplines, it is rarely studied in the context of online social interactions and joint actions. During online joint actions, language and gesture are often insufficient and humans typically use non-verbal, sensorimotor forms of communication to send coordination signals. For example, when playing volleyball, an athlete can exaggerate her movements to signal her intentions to her teammates (say, a pass to the right or to feint an adversary. Similarly, a person who is transporting a table together with a co-actor can push the table in a certain direction to signal where and when he intends to place it. Other examples of "signaling" are over-articulating in noisy environments and over-emphasizing vowels in child-directed speech. In all these examples, humans intentionally modify their action kinematics to make their goals easier to disambiguate. At the moment no formal theory exists of these forms of sensorimotor communication and signaling. We present one such theory that describes signaling as a combination of a pragmatic and a communicative action, and explains how it simplifies coordination in online social interactions. We cast signaling within a "joint action optimization" framework in which co-actors optimize the success of their interaction and joint goals rather than only their part of the joint action. The decision of whether and how much to signal requires solving a trade-off between the costs of modifying one's behavior and the benefits in terms of interaction success. Signaling is thus an intentional strategy that supports social interactions; it acts in concert with automatic mechanisms of resonance, prediction, and imitation, especially when the context makes actions and intentions ambiguous and difficult to read. Our theory suggests that communication dynamics should be studied within theories of coordination and interaction rather than only in terms of the

  10. Inhibition in the Human Auditory Cortex.

    Directory of Open Access Journals (Sweden)

    Koji Inui

    Full Text Available Despite their indispensable roles in sensory processing, little is known about inhibitory interneurons in humans. Inhibitory postsynaptic potentials cannot be recorded non-invasively, at least in a pure form, in humans. We herein sought to clarify whether prepulse inhibition (PPI in the auditory cortex reflected inhibition via interneurons using magnetoencephalography. An abrupt increase in sound pressure by 10 dB in a continuous sound was used to evoke the test response, and PPI was observed by inserting a weak (5 dB increase for 1 ms prepulse. The time course of the inhibition evaluated by prepulses presented at 10-800 ms before the test stimulus showed at least two temporally distinct inhibitions peaking at approximately 20-60 and 600 ms that presumably reflected IPSPs by fast spiking, parvalbumin-positive cells and somatostatin-positive, Martinotti cells, respectively. In another experiment, we confirmed that the degree of the inhibition depended on the strength of the prepulse, but not on the amplitude of the prepulse-evoked cortical response, indicating that the prepulse-evoked excitatory response and prepulse-evoked inhibition reflected activation in two different pathways. Although many diseases such as schizophrenia may involve deficits in the inhibitory system, we do not have appropriate methods to evaluate them; therefore, the easy and non-invasive method described herein may be clinically useful.

  11. Response of the sensorimotor cortex of cerebral palsy rats receiving transplantation of vascular endothelial growth factor 165-transfected neural stem cells

    Institute of Scientific and Technical Information of China (English)

    Jielu Tan; Xiangrong Zheng; Shanshan Zhang; Yujia Yang; Xia Wang; Xiaohe Yu; Le Zhong

    2014-01-01

    Neural stem cells are characterized by the ability to differentiate and stably express exogenous ge-nes. Vascular endothelial growth factor plays a role in protecting local blood vessels and neurons of newborn rats with hypoxic-ischemic encephalopathy. Transplantation of vascular endothelial growth factor-transfected neural stem cells may be neuroprotective in rats with cerebral palsy. In this study, 7-day-old Sprague-Dawley rats were divided into ifve groups: (1) sham operation (control), (2) cerebral palsy model alone or with (3) phosphate-buffered saline, (4) vascular en-dothelial growth factor 165 + neural stem cells, or (5) neural stem cells alone. hTe cerebral palsy model was established by ligating the letf common carotid artery followed by exposure to hypox-ia. Phosphate-buffered saline, vascular endothelial growth factor + neural stem cells, and neural stem cells alone were administered into the sensorimotor cortex using the stereotaxic instrument and microsyringe. Atfer transplantation, the radial-arm water maze test and holding test were performed. Immunohistochemistry for vascular endothelial growth factor and histology using hematoxylin-eosin were performed on cerebral cortex. Results revealed that the number of vas-cular endothelial growth factor-positive cells in cerebral palsy rats transplanted with vascular endothelial growth factor-transfected neural stem cells was increased, the time for ifnding water and the ifnding repetitions were reduced, the holding time was prolonged, and the degree of cell degeneration or necrosis was reduced. hTese ifndings indicate that the transplantation of vascu-lar endothelial growth factor-transfected neural stem cells alleviates brain damage and cognitive deifcits, and is neuroprotective in neonatal rats with hypoxia ischemic-mediated cerebral palsy.

  12. Music-supported therapy induces plasticity in the sensorimotor cortex in chronic stroke: a single-case study using multimodal imaging (fMRI-TMS).

    Science.gov (United States)

    Rojo, Nuria; Amengual, Julian; Juncadella, Montserrat; Rubio, Francisco; Camara, Estela; Marco-Pallares, Josep; Schneider, Sabine; Veciana, Misericordia; Montero, Jordi; Mohammadi, Bahram; Altenmüller, Eckart; Grau, Carles; Münte, Thomas F; Rodriguez-Fornells, Antoni

    2011-01-01

    Music-Supported Therapy (MST) has been developed recently in order to improve the use of the affected upper extremity after stroke. This study investigated the neuroplastic mechanisms underlying effectiveness in a patient with chronic stroke. MST uses musical instruments, a midi piano and an electronic drum set emitting piano sounds, to retrain fine and gross movements of the paretic upper extremity. Data are presented from a patient with a chronic stroke (20 months post-stroke) with residual right-sided hemiparesis who took part in 20 MST sessions over the course of 4 weeks. Post-therapy, a marked improvement of movement quality, assessed by 3D movement analysis, was observed. Moreover, functional magnetic resonance imaging (fMRI) of a sequential hand movement revealed distinct therapy-related changes in the form of a reduction of excess contralateral and ipsilateral activations. This was accompanied by changes in cortical excitability evidenced by transcranial magnetic stimulation (TMS). Functional MRI in a music listening task suggests that one of the effects of MST is the task-dependent coupling of auditory and motor cortical areas. The MST appears to be a useful neurorehabilitation tool in patients with chronic stroke and leads to neural reorganization in the sensorimotor cortex.

  13. Effects of Anodal High-Definition Transcranial Direct Current Stimulation on Bilateral Sensorimotor Cortex Activation During Sequential Finger Movements: An fNIRS Study.

    Science.gov (United States)

    Muthalib, Makii; Besson, Pierre; Rothwell, John; Ward, Tomas; Perrey, Stephane

    2016-01-01

    Transcranial direct current stimulation (tDCS) is a non-invasive electrical brain stimulation technique that can modulate cortical neuronal excitability and activity. This study utilized functional near infrared spectroscopy (fNIRS) neuroimaging to determine the effects of anodal high-definition (HD)-tDCS on bilateral sensorimotor cortex (SMC) activation. Before (Pre), during (Online), and after (Offline) anodal HD-tDCS (2 mA, 20 min) targeting the left SMC, eight healthy subjects performed a simple finger sequence (SFS) task with their right or left hand in an alternating blocked design (30-s rest and 30-s SFS task, repeated five times). In order to determine the level of bilateral SMC activation during the SFS task, an Oxymon MkIII fNIRS system was used to measure from the left and right SMC, changes in oxygenated (O2Hb) and deoxygenated (HHb) haemoglobin concentration values. The fNIRS data suggests a finding that compared to the Pre condition both the "Online" and "Offline" anodal HD-tDCS conditions induced a significant reduction in bilateral SMC activation (i.e., smaller decrease in HHb) for a similar motor output (i.e., SFS tap rate). These findings could be related to anodal HD-tDCS inducing a greater efficiency of neuronal transmission in the bilateral SMC to perform the same SFS task.

  14. Effects of Dopamine D2/D3 Blockade on Human Sensory and Sensorimotor Gating in Initially Antipsychotic-Naive, First-Episode Schizophrenia Patients

    DEFF Research Database (Denmark)

    Düring, Signe; Glenthøj, Birte Y; Andersen, Gitte Saltoft

    2014-01-01

    It has been suggested that psychophysiological measures of sensory and sensorimotor gating, P50 gating and prepulse inhibition of the startle reflex (PPI), underlie core features of schizophrenia and are linked to dopaminergic pathways in the striatum and prefrontal cortex. In the present study, ...

  15. Human-Inspired Eigenmovement Concept Provides Coupling-Free Sensorimotor Control in Humanoid Robot

    Directory of Open Access Journals (Sweden)

    Thomas Mergner

    2017-04-01

    Full Text Available Control of a multi-body system in both robots and humans may face the problem of destabilizing dynamic coupling effects arising between linked body segments. The state of the art solutions in robotics are full state feedback controllers. For human hip-ankle coordination, a more parsimonious and theoretically stable alternative to the robotics solution has been suggested in terms of the Eigenmovement (EM control. Eigenmovements are kinematic synergies designed to describe the multi DoF system, and its control, with a set of independent, and hence coupling-free, scalar equations. This paper investigates whether the EM alternative shows “real-world robustness” against noisy and inaccurate sensors, mechanical non-linearities such as dead zones, and human-like feedback time delays when controlling hip-ankle movements of a balancing humanoid robot. The EM concept and the EM controller are introduced, the robot's dynamics are identified using a biomechanical approach, and robot tests are performed in a human posture control laboratory. The tests show that the EM controller provides stable control of the robot with proactive (“voluntary” movements and reactive balancing of stance during support surface tilts and translations. Although a preliminary robot-human comparison reveals similarities and differences, we conclude (i the Eigenmovement concept is a valid candidate when different concepts of human sensorimotor control are considered, and (ii that human-inspired robot experiments may help to decide in future the choice among the candidates and to improve the design of humanoid robots and robotic rehabilitation devices.

  16. Monocular Visual Deprivation Suppresses Excitability in Adult Human Visual Cortex

    DEFF Research Database (Denmark)

    Lou, Astrid Rosenstand; Madsen, Kristoffer Hougaard; Paulson, Olaf Bjarne

    2011-01-01

    The adult visual cortex maintains a substantial potential for plasticity in response to a change in visual input. For instance, transcranial magnetic stimulation (TMS) studies have shown that binocular deprivation (BD) increases the cortical excitability for inducing phosphenes with TMS. Here, we...... of visual deprivation has a substantial impact on experience-dependent plasticity of the human visual cortex.......The adult visual cortex maintains a substantial potential for plasticity in response to a change in visual input. For instance, transcranial magnetic stimulation (TMS) studies have shown that binocular deprivation (BD) increases the cortical excitability for inducing phosphenes with TMS. Here, we...... employed TMS to trace plastic changes in adult visual cortex before, during, and after 48 h of monocular deprivation (MD) of the right dominant eye. In healthy adult volunteers, MD-induced changes in visual cortex excitability were probed with paired-pulse TMS applied to the left and right occipital cortex...

  17. Human umbilical cord blood cells restore brain damage induced changes in rat somatosensory cortex.

    Directory of Open Access Journals (Sweden)

    Maren Geissler

    Full Text Available Intraperitoneal transplantation of human umbilical cord blood (hUCB cells has been shown to reduce sensorimotor deficits after hypoxic ischemic brain injury in neonatal rats. However, the neuronal correlate of the functional recovery and how such a treatment enforces plastic remodelling at the level of neural processing remains elusive. Here we show by in-vivo recordings that hUCB cells have the capability of ameliorating the injury-related impairment of neural processing in primary somatosensory cortex. Intact cortical processing depends on a delicate balance of inhibitory and excitatory transmission, which is disturbed after injury. We found that the dimensions of cortical maps and receptive fields, which are significantly altered after injury, were largely restored. Additionally, the lesion induced hyperexcitability was no longer observed in hUCB treated animals as indicated by a paired-pulse behaviour resembling that observed in control animals. The beneficial effects on cortical processing were reflected in an almost complete recovery of sensorimotor behaviour. Our results demonstrate that hUCB cells reinstall the way central neurons process information by normalizing inhibitory and excitatory processes. We propose that the intermediate level of cortical processing will become relevant as a new stage to investigate efficacy and mechanisms of cell therapy in the treatment of brain injury.

  18. Diagnostic benefits of presurgical fMRI in patients with brain tumours in the primary sensorimotor cortex

    Energy Technology Data Exchange (ETDEWEB)

    Wengenroth, Martina; Blatow, M.; Guenther, J. [University of Heidelberg Medical School, Department of Neuroradiology, Heidelberg (Germany); Akbar, M. [University of Heidelberg Medical School, Department of Orthopaedics, Heidelberg (Germany); Tronnier, V.M. [University of Schleswig-Holstein, Department of Neurosurgery, Luebeck (Germany); Stippich, C. [University Hospital Basle, Department of Diagnostic and Interventional Neuroradiology, Basle (Switzerland)

    2011-07-15

    Reliable imaging of eloquent tumour-adjacent brain areas is necessary for planning function-preserving neurosurgery. This study evaluates the potential diagnostic benefits of presurgical functional magnetic resonance imaging (fMRI) in comparison to a detailed analysis of morphological MRI data. Standardised preoperative functional and structural neuroimaging was performed on 77 patients with rolandic mass lesions at 1.5 Tesla. The central region of both hemispheres was allocated using six morphological and three functional landmarks. fMRI enabled localisation of the motor hand area in 76/77 patients, which was significantly superior to analysis of structural MRI (confident localisation of motor hand area in 66/77 patients; p < 0.002). FMRI provided additional diagnostic information in 96% (tongue representation) and 97% (foot representation) of patients. FMRI-based presurgical risk assessment correlated in 88% with a positive postoperative clinical outcome. Routine presurgical FMRI allows for superior assessment of the spatial relationship between brain tumour and motor cortex compared with a very detailed analysis of structural 3D MRI, thus significantly facilitating the preoperative risk-benefit assessment and function-preserving surgery. The additional imaging time seems justified. FMRI has the potential to reduce postoperative morbidity and therefore hospitalisation time. (orig.)

  19. Humans can integrate feedback of discrete events in their sensorimotor control of a robotic hand.

    Science.gov (United States)

    Cipriani, Christian; Segil, Jacob L; Clemente, Francesco; ff Weir, Richard F; Edin, Benoni

    2014-11-01

    Providing functionally effective sensory feedback to users of prosthetics is a largely unsolved challenge. Traditional solutions require high band-widths for providing feedback for the control of manipulation and yet have been largely unsuccessful. In this study, we have explored a strategy that relies on temporally discrete sensory feedback that is technically simple to provide. According to the Discrete Event-driven Sensory feedback Control (DESC) policy, motor tasks in humans are organized in phases delimited by means of sensory encoded discrete mechanical events. To explore the applicability of DESC for control, we designed a paradigm in which healthy humans operated an artificial robot hand to lift and replace an instrumented object, a task that can readily be learned and mastered under visual control. Assuming that the central nervous system of humans naturally organizes motor tasks based on a strategy akin to DESC, we delivered short-lasting vibrotactile feedback related to events that are known to forcefully affect progression of the grasp-lift-and-hold task. After training, we determined whether the artificial feedback had been integrated with the sensorimotor control by introducing short delays and we indeed observed that the participants significantly delayed subsequent phases of the task. This study thus gives support to the DESC policy hypothesis. Moreover, it demonstrates that humans can integrate temporally discrete sensory feedback while controlling an artificial hand and invites further studies in which inexpensive, noninvasive technology could be used in clever ways to provide physiologically appropriate sensory feedback in upper limb prosthetics with much lower band-width requirements than with traditional solutions.

  20. Hypoactivation of the primary sensorimotor cortex in de novo Parkinson's disease. A motor fMRI study under controlled conditions

    Energy Technology Data Exchange (ETDEWEB)

    Tessa, Carlo; Vignali, Claudio [Versilia Hospital, AUSL Versilia, Division of Radiology, Camaiore (Italy); Lucetti, Claudio [Versilia Hospital, AUSL Versilia, Division of Neurology, Camaiore (Italy); Diciotti, Stefano; Paoli, Lorenzo; Ginestroni, Andrea; Mascalchi, Mario [University of Florence, Radiodiagnostic Section, Department of Clinical Physiopathology, Florence (Italy); Cecchi, Paolo; Baldacci, Filippo [University of Pisa, Department of Neuroscience, Pisa (Italy); Giannelli, Marco [Azienda Ospedaliero-Universitaria Pisana, Unit of Medical Physics, Pisa (Italy); Bonuccelli, Ubaldo [Versilia Hospital, AUSL Versilia, Division of Neurology, Camaiore (Italy); University of Pisa, Department of Neuroscience, Pisa (Italy)

    2012-03-15

    Nuclear medicine studies in Parkinson's disease (PD) indicate that nigrostriatal damage causes a widespread cortical hypoactivity assumed to be due to reduced excitatory thalamic outflow. However, so far, functional MRI (fMRI) studies have provided controversial data about this ''functional deafferentation'' phenomenon. To further clarify this issue, we assessed, with fMRI, de novo drug-naive PD patients using a relatively complex motor task under strictly controlled conditions. Nineteen de novo PD patients with right-predominant or bilateral symptoms and 13 age-matched healthy volunteers performed continuous writing of ''8'' figures with the right-dominant hand using a MR-compatible device that enables identification of incorrectly performed tasks and measures the size and the frequency of the ''8''s. The data were analyzed with FSL software and correlated with the clinical severity rated according to the Hoehn and Yahr (HY) staging system. Fifteen (89%) of 19 PD patients and 12 (92%) of 13 controls correctly executed the task. PD patients showed significant hypoactivation of the left primary sensorimotor cortex (SM1) and cerebellum and no hyperactive areas as compared to controls. However, activation in SM1 and supplementary motor area bilaterally, in left supramarginal, parietal inferior, parietal superior and frontal superior gyri as well as in right parietal superior and angular gyri paralleled increasing disease severity as assessed with the HY stage. In line with the ''deafferentation hypothesis'', fMRI demonstrates hypoactivation of the SM1 in the early clinical stage of PD. (orig.)

  1. Human primary visual cortex topography imaged via positron tomography

    International Nuclear Information System (INIS)

    Schwartz, E.L.; Christman, D.R.; Wolf, A.P.

    1984-01-01

    The visuotopic structure of primary visual cortex was studied in a group of 7 human volunteers using positron emission transaxial tomography (PETT) and 18 F-labeled 2-deoxy-2-fluoro-D-glucose ([ 18 F]DG). A computer animation was constructed with a spatial structure which was matched to estimates of human cortical magnification factor and to striate cortex stimulus preferences. A lateralized cortical 'checker-board' pattern of [ 18 F]DG was stimulated in primary visual cortex by having subjects view this computer animation following i.v. injection of [ 18 F]DG. The spatial structure of the stimulus was designed to produce an easily recognizable 'signature' in a series of 9 serial PETT scans obtained from each of a group of 7 volunteers. The predicted lateralized topographic 'signature' was observed in 6 of 7 subjects. Applications of this method for further PETT studies of human visual cortex are discussed. (Auth.)

  2. In vivo magnetic resonance spectroscopy measurement of gray-matter and white-matter gamma-aminobutyric acid concentration in sensorimotor cortex using a motion-controlled MEGA point-resolved spectroscopy sequence.

    Science.gov (United States)

    Bhattacharyya, Pallab K; Phillips, Micheal D; Stone, Lael A; Lowe, Mark J

    2011-04-01

    Gamma-aminobutyric acid (GABA) is a major inhibitory neurotransmitter in the brain. Understanding the GABA concentration, in vivo, is important to understand normal brain function. Using MEGA point-resolved spectroscopy sequence with interleaved water scans to detect subject motion, GABA level of sensorimotor cortex was measured using a voxel identified from a functional magnetic resonance imaging scan. The GABA level in a 20×20×20-mm(3) voxel consisting of 37%±7% gray matter, 52%±12% white matter and 11%±8% cerebrospinal fluid in the sensorimotor region was measured to be 1.43±0.48 mM. In addition, using linear regression analysis, GABA concentrations within gray and white matter were calculated to be 2.87±0.61 and 0.33±0.11 mM, respectively. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Independent delta/theta rhythms in the human hippocampus and entorhinal cortex

    Directory of Open Access Journals (Sweden)

    Florian Mormann

    2008-05-01

    Full Text Available Theta oscillations in the medial temporal lobe (MTL of mammals are involved in various functions such as spatial navigation, sensorimotor integration, and cognitive processing. While the theta rhythm was originally assumed to originate in the medial septum, more recent studies suggest autonomous theta generation in the MTL. Although coherence between entorhinal and hippocampal theta activity has been found to influence memory formation, it remains unclear whether these two structures can generate theta independently. In this study we analyzed intracranial electroencephalographic (EEG recordings from 22 patients with unilateral hippocampal sclerosis undergoing presurgical evaluation prior to resection of the epileptic focus. Using a wavelet-based, frequency-band-specific measure of phase synchronization, we quantified synchrony between 10 different recording sites along the longitudinal axis of the hippocampal formation in the non-epileptic brain hemisphere. We compared EEG synchrony between adjacent recording sites (i within the entorhinal cortex, (ii within the hippocampus, and (iii between the hippocampus and entorhinal cortex. We observed a significant interregional gap in synchrony for the delta and theta band, indicating the existence of independent delta/theta rhythms in different subregions of the human MTL. The interaction of these rhythms could represent the temporal basis for the information processing required for mnemonic encoding and retrieval.

  4. Preprocessing of emotional visual information in the human piriform cortex.

    Science.gov (United States)

    Schulze, Patrick; Bestgen, Anne-Kathrin; Lech, Robert K; Kuchinke, Lars; Suchan, Boris

    2017-08-23

    This study examines the processing of visual information by the olfactory system in humans. Recent data point to the processing of visual stimuli by the piriform cortex, a region mainly known as part of the primary olfactory cortex. Moreover, the piriform cortex generates predictive templates of olfactory stimuli to facilitate olfactory processing. This study fills the gap relating to the question whether this region is also capable of preprocessing emotional visual information. To gain insight into the preprocessing and transfer of emotional visual information into olfactory processing, we recorded hemodynamic responses during affective priming using functional magnetic resonance imaging (fMRI). Odors of different valence (pleasant, neutral and unpleasant) were primed by images of emotional facial expressions (happy, neutral and disgust). Our findings are the first to demonstrate that the piriform cortex preprocesses emotional visual information prior to any olfactory stimulation and that the emotional connotation of this preprocessing is subsequently transferred and integrated into an extended olfactory network for olfactory processing.

  5. A Human-Robot Co-Manipulation Approach Based on Human Sensorimotor Information.

    Science.gov (United States)

    Peternel, Luka; Tsagarakis, Nikos; Ajoudani, Arash

    2017-07-01

    This paper aims to improve the interaction and coordination between the human and the robot in cooperative execution of complex, powerful, and dynamic tasks. We propose a novel approach that integrates online information about the human motor function and manipulability properties into the hybrid controller of the assistive robot. Through this human-in-the-loop framework, the robot can adapt to the human motor behavior and provide the appropriate assistive response in different phases of the cooperative task. We experimentally evaluate the proposed approach in two human-robot co-manipulation tasks that require specific complementary behavior from the two agents. Results suggest that the proposed technique, which relies on a minimum degree of task-level pre-programming, can achieve an enhanced physical human-robot interaction performance and deliver appropriate level of assistance to the human operator.

  6. Social Sensorimotor Contingencies

    OpenAIRE

    Bütepage, Judith

    2016-01-01

    As the field of robotics advances, more robots are employed in our everyday environment. Thus, the implementation of robots that can actively engage in physical collaboration and naturally interact with humans is of high importance. In order to achieve this goal, it is necessary to study human interaction and social cognition and how these aspects can be implemented in robotic agents. The theory of social sensorimotor contingencies hypothesises that many aspects of human-human interaction de...

  7. Expression of glial fibrillar acidic protein in the sensorimotor cortex of the cerebral hemispheres in the modeling of transient ischemia against the background of previous sensitization by brain antigen and immunocorrection

    Directory of Open Access Journals (Sweden)

    L. M. Yaremenko

    2017-12-01

    Full Text Available Aim. In order to analyze the dynamics of expression of glial fibrillar acidic protein in the sensorimotor cortex of the large hemispheres in the simulation of transient ischemia against the background of previous sensitization by brain antigen and immunocorrection. Materials and methods. The study is conducted on 185 male mature white rats from Wistar line weighing 260-290 g, in which the damage of the brain was modulated. The brain for study was taken on the 1st, 3rd, 10th, 30th and 90th days after the start of the experiment. The histological, immunohistochemical, morphometric and statistical methods were used. Results. Observations have shown that sensitization by the brain antigen causes neurodegenerative changes in the sensorimotor cortex and a moderate increase in the number of GFAP+-gliocytes, which is gradually increasing. The discirculatory changes that occurred with PO and BCA against the background of previous sensitization practically do not lead to changes in the number of GFAP+-cells. Against the background of sensitization by brain antigen, brain ischemia leads to an increase in the number of gliocytes that are GFAP labeled. In the affected hemisphere, their number reaches a maximum in the end of the acute period of ischemia, after which it decreases. But even in 3 months after transient vascular lesion, there are almost twice as many as in conditionally intact rats. This can be a factor that will significantly affect the function of brain regions after a vascular accident. The increase in the number of GFAP+-gliocytes in the contralateral hemisphere allows us to speak about a certain systemic response of astrocytic glia after ischemic trauma. An early reaction to increase of the number of labeled astrocytes just a day after ischemic attack suggests that some of this type of gliocytes does not expresses GFAP under normal conditions. The action of Imunofan in MEAs results in a less significant decrease in manifestations of

  8. Enhanced attentional gain as a mechanism for generalized perceptual learning in human visual cortex.

    Science.gov (United States)

    Byers, Anna; Serences, John T

    2014-09-01

    Learning to better discriminate a specific visual feature (i.e., a specific orientation in a specific region of space) has been associated with plasticity in early visual areas (sensory modulation) and with improvements in the transmission of sensory information from early visual areas to downstream sensorimotor and decision regions (enhanced readout). However, in many real-world scenarios that require perceptual expertise, observers need to efficiently process numerous exemplars from a broad stimulus class as opposed to just a single stimulus feature. Some previous data suggest that perceptual learning leads to highly specific neural modulations that support the discrimination of specific trained features. However, the extent to which perceptual learning acts to improve the discriminability of a broad class of stimuli via the modulation of sensory responses in human visual cortex remains largely unknown. Here, we used functional MRI and a multivariate analysis method to reconstruct orientation-selective response profiles based on activation patterns in the early visual cortex before and after subjects learned to discriminate small offsets in a set of grating stimuli that were rendered in one of nine possible orientations. Behavioral performance improved across 10 training sessions, and there was a training-related increase in the amplitude of orientation-selective response profiles in V1, V2, and V3 when orientation was task relevant compared with when it was task irrelevant. These results suggest that generalized perceptual learning can lead to modified responses in the early visual cortex in a manner that is suitable for supporting improved discriminability of stimuli drawn from a large set of exemplars. Copyright © 2014 the American Physiological Society.

  9. Motor Skills Training Enhances α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid Receptor Subunit mRNA Expression in the Ipsilateral Sensorimotor Cortex and Striatum of Rats Following Intracerebral Hemorrhage.

    Science.gov (United States)

    Tamakoshi, Keigo; Ishida, Kazuto; Kawanaka, Kentaro; Takamatsu, Yasuyuki; Tamaki, Hiroyuki

    2017-10-01

    We investigated the effects of acrobatic training (AT) on expression of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) subunits in the sensorimotor cortex and striatum after intracerebral hemorrhage (ICH). Male Wistar rats were divided into 4 groups: ICH without AT (ICH), ICH with AT (ICH + AT), sham operation without AT (SHAM), and sham operation with AT (SHAM + AT). ICH was induced by collagenase injection into the left striatum. The ICH + AT group performed 5 acrobatic tasks daily on days 4-28 post ICH. Forelimb sensorimotor function was evaluated using the forelimb placing test. On days 14 and 29, mRNA expression levels of AMPAR subunits GluR1-4 were measured by real-time reverse transcription-polymerase chain reaction. Forelimb placing test scores were significantly higher in the ICH + AT group than in the ICH group. Expression levels of all AMPAR subunit mRNAs were significantly higher in the ipsilateral sensorimotor cortex of rats in the ICH + AT group than in that of rats in the ICH group on day 29. GluR3 and GluR4 expression levels were reduced in the ipsilateral striatum of rats in the ICH group compared with that of rats in the SHAM group on day 14. These changes may play a critical role in motor skills training-induced recovery after ICH. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  10. Cognitive demand of human sensorimotor performance during an extended space mission: a dual-task study.

    Science.gov (United States)

    Bock, Otmar; Weigelt, Cornelia; Bloomberg, Jacob J

    2010-09-01

    Two previous single-case studies found that the dual-task costs of manual tracking plus memory search increased during a space mission, and concluded that sensorimotor deficits during spaceflight may be related to cognitive overload. Since dual-task costs were insensitive to the difficulty of memory search, the authors argued that the overload may reflect stress-related problems of multitasking, rather than a scarcity of specific cognitive resources. Here we expand the available database and compare different types of concurrent task. Three subjects were repeatedly tested before, during, and after an extended mission on the International Space Station (ISS). They performed an unstable tracking task and four reaction-time tasks, both separately and concurrently. Inflight data could only be obtained during later parts of the mission. The tracking error increased from pre- to in flight by a factor of about 2, both under single- and dual-task conditions. The dual-task costs with a reaction-time task requiring rhythm production was 2.4 times higher than with a reaction-time task requiring visuo-spatial transformations, and 8 times higher than with a regular choice reaction-time task. Long-term sensorimotor deficits during spaceflight may reflect not only stress, but also a scarcity of resources related to complex motor programming; possibly those resources are tied up by sensorimotor adaptation to the space environment.

  11. Monetary reward activates human prefrontal cortex

    International Nuclear Information System (INIS)

    Thut, G.; Roelcke, U.; Nienhusmeier, M.; Missimer, J.; Maguire, R.P.; Leenders, K.L.; Schultz, W.

    1997-01-01

    We present a rCBF PET activation study, in which we demonstrated that reward processing in humans activates a cortical-subcortical network including dorsolateral prefrontal, orbital frontal, thalamic and midbrain regions. It is suggested that, as found for non-human primates, the basal ganglia-thalamo-cortical system is implicated in reward processing. (author) 1 fig., 3 refs

  12. Subplate in the developing cortex of mouse and human

    DEFF Research Database (Denmark)

    Wang, Wei Zhi; Hoerder-Suabedissen, Anna; Oeschger, Franziska M

    2010-01-01

    Abstract The subplate is a largely transient zone containing precocious neurons involved in several key steps of cortical development. The majority of subplate neurons form a compact layer in mouse, but are dispersed throughout a much larger zone in the human. In rodent, subplate neurons are among...... several genes that are specifically expressed in the subplate layer of the rodent dorsal cortex. Here we examined the human subplate for some of these markers. In the human dorsal cortex, connective tissue growth factor-positive neurons can be seen in the ventricular zone at 15-22 postconceptional weeks...... growth factor- and nuclear receptor-related 1-positive cells are two distinct cell populations of the human subplate. Furthermore, our microarray analysis in rodent suggested that subplate neurons produce plasma proteins. Here we demonstrate that the human subplate also expresses alpha2zinc...

  13. Functional sex differences in human primary auditory cortex

    NARCIS (Netherlands)

    Ruytjens, Liesbet; Georgiadis, Janniko R.; Holstege, Gert; Wit, Hero P.; Albers, Frans W. J.; Willemsen, Antoon T. M.

    2007-01-01

    Background We used PET to study cortical activation during auditory stimulation and found sex differences in the human primary auditory cortex (PAC). Regional cerebral blood flow (rCBF) was measured in 10 male and 10 female volunteers while listening to sounds (music or white noise) and during a

  14. A novel dual-site transcranial magnetic stimulation paradigm to probe fast facilitatory inputs from ipsilateral dorsal premotor cortex to primary motor cortex

    DEFF Research Database (Denmark)

    Groppa, Sergiu; Werner-Petroll, Nicole; Münchau, Alexander

    2012-01-01

    The dorsal premotor cortex (PMd) plays an import role in action control, sensorimotor integration and motor recovery. Animal studies and human data have demonstrated direct connections between ipsilateral PMd and primary motor cortex hand area (M1(HAND)). In this study we adopted a multimodal app...

  15. Decoding color responses in human visual cortex

    International Nuclear Information System (INIS)

    Kuriki, Ichiro; Matsumiya, Kazumichi; Shioiri, Satoshi; Nakamura, Shingo; Sun, Pei; Ueno, Kenichi; Tanaka, Keiji; Cheng, Kang

    2011-01-01

    Color percept is a subjective experience and, in general, it is impossible for other people to tell someone's color percept. The present study demonstrated that the simple image-classification analysis of brain activity obtained by a functional magnetic resonance imaging (fMRI) technique enables to tell which of four colors the subject is looking at. Our results also imply that color information is coded by the responses of hue-selective neurons in human brain, not by the combinations of red-green and blue-yellow hue components. (author)

  16. Spindle neurons of the human anterior cingulate cortex

    Science.gov (United States)

    Nimchinsky, E. A.; Vogt, B. A.; Morrison, J. H.; Hof, P. R.; Bloom, F. E. (Principal Investigator)

    1995-01-01

    The human anterior cingulate cortex is distinguished by the presence of an unusual cell type, a large spindle neuron in layer Vb. This cell has been noted numerous times in the historical literature but has not been studied with modern neuroanatomic techniques. For instance, details regarding the neuronal class to which these cells belong and regarding their precise distribution along both ventrodorsal and anteroposterior axes of the cingulate gyrus are still lacking. In the present study, morphological features and the anatomic distribution of this cell type were studied using computer-assisted mapping and immunocytochemical techniques. Spindle neurons are restricted to the subfields of the anterior cingulate cortex (Brodmann's area 24), exhibiting a greater density in anterior portions of this area than in posterior portions, and tapering off in the transition zone between anterior and posterior cingulate cortex. Furthermore, a majority of the spindle cells at any level is located in subarea 24b on the gyral surface. Immunocytochemical analysis revealed that the neurofilament protein triple was present in a large percentage of these neurons and that they did not contain calcium-binding proteins. Injections of the carbocyanine dye DiI into the cingulum bundle revealed that these cells are projection neurons. Finally, spindle cells were consistently affected in Alzheimer's disease cases, with an overall loss of about 60%. Taken together, these observations indicate that the spindle cells of the human cingulate cortex represent a morphological subpopulation of pyramidal neurons whose restricted distribution may be associated with functionally distinct areas.

  17. Transcranial static magnetic field stimulation of the human motor cortex

    Science.gov (United States)

    Oliviero, Antonio; Mordillo-Mateos, Laura; Arias, Pablo; Panyavin, Ivan; Foffani, Guglielmo; Aguilar, Juan

    2011-01-01

    Abstract The aim of the present study was to investigate in healthy humans the possibility of a non-invasive modulation of motor cortex excitability by the application of static magnetic fields through the scalp. Static magnetic fields were obtained by using cylindrical NdFeB magnets. We performed four sets of experiments. In Experiment 1, we recorded motor potentials evoked by single-pulse transcranial magnetic stimulation (TMS) of the motor cortex before and after 10 min of transcranial static magnetic field stimulation (tSMS) in conscious subjects. We observed an average reduction of motor cortex excitability of up to 25%, as revealed by TMS, which lasted for several minutes after the end of tSMS, and was dose dependent (intensity of the magnetic field) but not polarity dependent. In Experiment 2, we confirmed the reduction of motor cortex excitability induced by tSMS using a double-blind sham-controlled design. In Experiment 3, we investigated the duration of tSMS that was necessary to modulate motor cortex excitability. We found that 10 min of tSMS (compared to 1 min and 5 min) were necessary to induce significant effects. In Experiment 4, we used transcranial electric stimulation (TES) to establish that the tSMS-induced reduction of motor cortex excitability was not due to corticospinal axon and/or spinal excitability, but specifically involved intracortical networks. These results suggest that tSMS using small static magnets may be a promising tool to modulate cerebral excitability in a non-invasive, painless, and reversible way. PMID:21807616

  18. Noninvasive studies of human visual cortex using neuromagnetic techniques

    International Nuclear Information System (INIS)

    Aine, C.J.; George, J.S.; Supek, S.; Maclin, E.L.

    1990-01-01

    The major goals of noninvasive studies of the human visual cortex are: to increase knowledge of the functional organization of cortical visual pathways; and to develop noninvasive clinical tests for the assessment of cortical function. Noninvasive techniques suitable for studies of the structure and function of human visual cortex include magnetic resonance imaging (MRI), positron emission tomography (PET), single photon emission tomography (SPECT), scalp recorded event-related potentials (ERPs), and event-related magnetic fields (ERFs). The primary challenge faced by noninvasive functional measures is to optimize the spatial and temporal resolution of the measurement and analytic techniques in order to effectively characterize the spatial and temporal variations in patterns of neuronal activity. In this paper we review the use of neuromagnetic techniques for this purpose. 8 refs., 3 figs

  19. Detection of optogenetic stimulation in somatosensory cortex by non-human primates--towards artificial tactile sensation.

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    May, Travis; Ozden, Ilker; Brush, Benjamin; Borton, David; Wagner, Fabien; Agha, Naubahar; Sheinberg, David L; Nurmikko, Arto V

    2014-01-01

    Neuroprosthesis research aims to enable communication between the brain and external assistive devices while restoring lost functionality such as occurs from stroke, spinal cord injury or neurodegenerative diseases. In future closed-loop sensorimotor prostheses, one approach is to use neuromodulation as direct stimulus to the brain to compensate for a lost sensory function and help the brain to integrate relevant information for commanding external devices via, e.g. movement intention. Current neuromodulation techniques rely mainly of electrical stimulation. Here we focus specifically on the question of eliciting a biomimetically relevant sense of touch by direct stimulus of the somatosensory cortex by introducing optogenetic techniques as an alternative to electrical stimulation. We demonstrate that light activated opsins can be introduced to target neurons in the somatosensory cortex of non-human primates and be optically activated to create a reliably detected sensation which the animal learns to interpret as a tactile sensation localized within the hand. The accomplishment highlighted here shows how optical stimulation of a relatively small group of mostly excitatory somatosensory neurons in the nonhuman primate brain is sufficient for eliciting a useful sensation from data acquired by simultaneous electrophysiology and from behavioral metrics. In this first report to date on optically neuromodulated behavior in the somatosensory cortex of nonhuman primates we do not yet dissect the details of the sensation the animals exerience or contrast it to those evoked by electrical stimulation, issues of considerable future interest.

  20. Detection of optogenetic stimulation in somatosensory cortex by non-human primates--towards artificial tactile sensation.

    Directory of Open Access Journals (Sweden)

    Travis May

    Full Text Available Neuroprosthesis research aims to enable communication between the brain and external assistive devices while restoring lost functionality such as occurs from stroke, spinal cord injury or neurodegenerative diseases. In future closed-loop sensorimotor prostheses, one approach is to use neuromodulation as direct stimulus to the brain to compensate for a lost sensory function and help the brain to integrate relevant information for commanding external devices via, e.g. movement intention. Current neuromodulation techniques rely mainly of electrical stimulation. Here we focus specifically on the question of eliciting a biomimetically relevant sense of touch by direct stimulus of the somatosensory cortex by introducing optogenetic techniques as an alternative to electrical stimulation. We demonstrate that light activated opsins can be introduced to target neurons in the somatosensory cortex of non-human primates and be optically activated to create a reliably detected sensation which the animal learns to interpret as a tactile sensation localized within the hand. The accomplishment highlighted here shows how optical stimulation of a relatively small group of mostly excitatory somatosensory neurons in the nonhuman primate brain is sufficient for eliciting a useful sensation from data acquired by simultaneous electrophysiology and from behavioral metrics. In this first report to date on optically neuromodulated behavior in the somatosensory cortex of nonhuman primates we do not yet dissect the details of the sensation the animals exerience or contrast it to those evoked by electrical stimulation, issues of considerable future interest.

  1. Decoding Speech With Integrated Hybrid Signals Recorded From the Human Ventral Motor Cortex

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    Kenji Ibayashi

    2018-04-01

    Full Text Available Restoration of speech communication for locked-in patients by means of brain computer interfaces (BCIs is currently an important area of active research. Among the neural signals obtained from intracranial recordings, single/multi-unit activity (SUA/MUA, local field potential (LFP, and electrocorticography (ECoG are good candidates for an input signal for BCIs. However, the question of which signal or which combination of the three signal modalities is best suited for decoding speech production remains unverified. In order to record SUA, LFP, and ECoG simultaneously from a highly localized area of human ventral sensorimotor cortex (vSMC, we fabricated an electrode the size of which was 7 by 13 mm containing sparsely arranged microneedle and conventional macro contacts. We determined which signal modality is the most capable of decoding speech production, and tested if the combination of these signals could improve the decoding accuracy of spoken phonemes. Feature vectors were constructed from spike frequency obtained from SUAs and event-related spectral perturbation derived from ECoG and LFP signals, then input to the decoder. The results showed that the decoding accuracy for five spoken vowels was highest when features from multiple signals were combined and optimized for each subject, and reached 59% when averaged across all six subjects. This result suggests that multi-scale signals convey complementary information for speech articulation. The current study demonstrated that simultaneous recording of multi-scale neuronal activities could raise decoding accuracy even though the recording area is limited to a small portion of cortex, which is advantageous for future implementation of speech-assisting BCIs.

  2. Functional sex differences in human primary auditory cortex

    International Nuclear Information System (INIS)

    Ruytjens, Liesbet; Georgiadis, Janniko R.; Holstege, Gert; Wit, Hero P.; Albers, Frans W.J.; Willemsen, Antoon T.M.

    2007-01-01

    We used PET to study cortical activation during auditory stimulation and found sex differences in the human primary auditory cortex (PAC). Regional cerebral blood flow (rCBF) was measured in 10 male and 10 female volunteers while listening to sounds (music or white noise) and during a baseline (no auditory stimulation). We found a sex difference in activation of the left and right PAC when comparing music to noise. The PAC was more activated by music than by noise in both men and women. But this difference between the two stimuli was significantly higher in men than in women. To investigate whether this difference could be attributed to either music or noise, we compared both stimuli with the baseline and revealed that noise gave a significantly higher activation in the female PAC than in the male PAC. Moreover, the male group showed a deactivation in the right prefrontal cortex when comparing noise to the baseline, which was not present in the female group. Interestingly, the auditory and prefrontal regions are anatomically and functionally linked and the prefrontal cortex is known to be engaged in auditory tasks that involve sustained or selective auditory attention. Thus we hypothesize that differences in attention result in a different deactivation of the right prefrontal cortex, which in turn modulates the activation of the PAC and thus explains the sex differences found in the activation of the PAC. Our results suggest that sex is an important factor in auditory brain studies. (orig.)

  3. Functional sex differences in human primary auditory cortex

    Energy Technology Data Exchange (ETDEWEB)

    Ruytjens, Liesbet [University Medical Center Groningen, Department of Otorhinolaryngology, Groningen (Netherlands); University Medical Center Utrecht, Department Otorhinolaryngology, P.O. Box 85500, Utrecht (Netherlands); Georgiadis, Janniko R. [University of Groningen, University Medical Center Groningen, Department of Anatomy and Embryology, Groningen (Netherlands); Holstege, Gert [University of Groningen, University Medical Center Groningen, Center for Uroneurology, Groningen (Netherlands); Wit, Hero P. [University Medical Center Groningen, Department of Otorhinolaryngology, Groningen (Netherlands); Albers, Frans W.J. [University Medical Center Utrecht, Department Otorhinolaryngology, P.O. Box 85500, Utrecht (Netherlands); Willemsen, Antoon T.M. [University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, Groningen (Netherlands)

    2007-12-15

    We used PET to study cortical activation during auditory stimulation and found sex differences in the human primary auditory cortex (PAC). Regional cerebral blood flow (rCBF) was measured in 10 male and 10 female volunteers while listening to sounds (music or white noise) and during a baseline (no auditory stimulation). We found a sex difference in activation of the left and right PAC when comparing music to noise. The PAC was more activated by music than by noise in both men and women. But this difference between the two stimuli was significantly higher in men than in women. To investigate whether this difference could be attributed to either music or noise, we compared both stimuli with the baseline and revealed that noise gave a significantly higher activation in the female PAC than in the male PAC. Moreover, the male group showed a deactivation in the right prefrontal cortex when comparing noise to the baseline, which was not present in the female group. Interestingly, the auditory and prefrontal regions are anatomically and functionally linked and the prefrontal cortex is known to be engaged in auditory tasks that involve sustained or selective auditory attention. Thus we hypothesize that differences in attention result in a different deactivation of the right prefrontal cortex, which in turn modulates the activation of the PAC and thus explains the sex differences found in the activation of the PAC. Our results suggest that sex is an important factor in auditory brain studies. (orig.)

  4. Virtual reality applications in assessing the effect of anxiety on sensorimotor integration in human postural control.

    Science.gov (United States)

    Widdowson, Christopher; Ganhotra, Jatin; Faizal, Mohammed; Wilko, Marissa; Parikh, Saurin; Adhami, Zainulabidin; Hernandez, Manuel E

    2016-08-01

    Falls are a leading cause of injury and mortality among adults over the age of 65 years. Given the strong relation between fear of falling and fall risk, identification of the mechanisms that underlie anxiety-related changes in postural control may pave the way to the development of novel therapeutic strategies aimed at reducing fall risk in older adults. First, we review potential mechanisms underlying anxiety-mediated changes in postural control in older adults with and without neurological conditions. We then present a system that allows for the simultaneous recording of neural, physiological, and behavioral data in an immersive virtual reality (VR) environment while implementing sensory and mechanical perturbations to evaluate alterations in sensorimotor integration under conditions with high postural threat. We also discuss applications of VR in minimizing falls in older adults and potential future studies.

  5. Cortico-Cortical Receptive Field Estimates in Human Visual Cortex

    Directory of Open Access Journals (Sweden)

    Koen V Haak

    2012-05-01

    Full Text Available Human visual cortex comprises many visual areas that contain a map of the visual field (Wandell et al 2007, Neuron 56, 366–383. These visual field maps can be identified readily in individual subjects with functional magnetic resonance imaging (fMRI during experimental sessions that last less than an hour (Wandell and Winawer 2011, Vis Res 718–737. Hence, visual field mapping with fMRI has been, and still is, a heavily used technique to examine the organisation of both normal and abnormal human visual cortex (Haak et al 2011, ACNR, 11(3, 20–21. However, visual field mapping cannot reveal every aspect of human visual cortex organisation. For example, the information processed within a visual field map arrives from somewhere and is sent to somewhere, and visual field mapping does not derive these input/output relationships. Here, we describe a new, model-based analysis for estimating the dependence between signals in distinct cortical regions using functional magnetic resonance imaging (fMRI data. Just as a stimulus-referred receptive field predicts the neural response as a function of the stimulus contrast, the neural-referred receptive field predicts the neural response as a function of responses elsewhere in the nervous system. When applied to two cortical regions, this function can be called the cortico-cortical receptive field (CCRF. We model the CCRF as a Gaussian-weighted region on the cortical surface and apply the model to data from both stimulus-driven and resting-state experimental conditions in visual cortex.

  6. A Model of Representational Spaces in Human Cortex.

    Science.gov (United States)

    Guntupalli, J Swaroop; Hanke, Michael; Halchenko, Yaroslav O; Connolly, Andrew C; Ramadge, Peter J; Haxby, James V

    2016-06-01

    Current models of the functional architecture of human cortex emphasize areas that capture coarse-scale features of cortical topography but provide no account for population responses that encode information in fine-scale patterns of activity. Here, we present a linear model of shared representational spaces in human cortex that captures fine-scale distinctions among population responses with response-tuning basis functions that are common across brains and models cortical patterns of neural responses with individual-specific topographic basis functions. We derive a common model space for the whole cortex using a new algorithm, searchlight hyperalignment, and complex, dynamic stimuli that provide a broad sampling of visual, auditory, and social percepts. The model aligns representations across brains in occipital, temporal, parietal, and prefrontal cortices, as shown by between-subject multivariate pattern classification and intersubject correlation of representational geometry, indicating that structural principles for shared neural representations apply across widely divergent domains of information. The model provides a rigorous account for individual variability of well-known coarse-scale topographies, such as retinotopy and category selectivity, and goes further to account for fine-scale patterns that are multiplexed with coarse-scale topographies and carry finer distinctions. © The Author 2016. Published by Oxford University Press.

  7. Humans can integrate force feedback to toes in their sensorimotor control of a robotic hand.

    Science.gov (United States)

    Panarese, Alessandro; Edin, Benoni B; Vecchi, Fabrizio; Carrozza, Maria C; Johansson, Roland S

    2009-12-01

    Tactile sensory feedback is essential for dexterous object manipulation. Users of hand myoelectric prostheses without tactile feedback must depend essentially on vision to control their device. Indeed, improved tactile feedback is one of their main priorities. Previous research has provided evidence that conveying tactile feedback can improve prostheses control, although additional effort is required to solve problems related to pattern recognition learning, unpleasant sensations, sensory adaptation, and low spatiotemporal resolution. Still, these studies have mainly focused on providing stimulation to hairy skin regions close to the amputation site, i.e., usually to the upper arm. Here, we explored the possibility to provide tactile feedback to the glabrous skin of toes, which have mechanical and neurophysiological properties similar to the fingertips. We explored this paradigm in a grasp-and-lift task, in which healthy participants controlled two opposing digits of a robotic hand by changing the spacing of their index finger and thumb. The normal forces applied by the robotic fingertips to a test object were fed back to the right big and second toe. We show that within a few lifting trials, all the participants incorporated the force feedback received by the foot in their sensorimotor control of the robotic hand.

  8. The development of human visual cortex and clinical implications

    Directory of Open Access Journals (Sweden)

    Siu CR

    2018-04-01

    Full Text Available Caitlin R Siu,1 Kathryn M Murphy1,2 1McMaster Integrative Neuroscience Discovery and Study (MiNDS Program, McMaster University, Hamilton, ON, Canada; 2Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, ON, Canada Abstract: The primary visual cortex (V1 is the first cortical area that processes visual information. Normal development of V1 depends on binocular vision during the critical period, and age-related losses of vision are linked with neurobiological changes in V1. Animal studies have provided important details about the neurobiological mechanisms in V1 that support normal vision or are changed by visual diseases. There is very little information, however, about those neurobiological mechanisms in human V1. That lack of information has hampered the translation of biologically inspired treatments from preclinical models to effective clinical treatments. We have studied human V1 to characterize the expression of neurobiological mechanisms that regulate visual perception and neuroplasticity. We have identified five stages of development for human V1 that start in infancy and continue across the life span. Here, we describe these stages, compare them with visual and anatomical milestones, and discuss implications for translating treatments for visual disorders that depend on neuroplasticity of V1 function. Keywords: development, human visual cortex, amblyopia, synaptic plasticity, glutamatergic, GABAergic, receptors

  9. Visual attentional load influences plasticity in the human motor cortex.

    Science.gov (United States)

    Kamke, Marc R; Hall, Michelle G; Lye, Hayley F; Sale, Martin V; Fenlon, Laura R; Carroll, Timothy J; Riek, Stephan; Mattingley, Jason B

    2012-05-16

    Neural plasticity plays a critical role in learning, memory, and recovery from injury to the nervous system. Although much is known about the physical and physiological determinants of plasticity, little is known about the influence of cognitive factors. In this study, we investigated whether selective attention plays a role in modifying changes in neural excitability reflecting long-term potentiation (LTP)-like plasticity. We induced LTP-like effects in the hand area of the human motor cortex using transcranial magnetic stimulation (TMS). During the induction of plasticity, participants engaged in a visual detection task with either low or high attentional demands. Changes in neural excitability were assessed by measuring motor-evoked potentials in a small hand muscle before and after the TMS procedures. In separate experiments plasticity was induced either by paired associative stimulation (PAS) or intermittent theta-burst stimulation (iTBS). Because these procedures induce different forms of LTP-like effects, they allowed us to investigate the generality of any attentional influence on plasticity. In both experiments reliable changes in motor cortex excitability were evident under low-load conditions, but this effect was eliminated under high-attentional load. In a third experiment we investigated whether the attentional task was associated with ongoing changes in the excitability of motor cortex, but found no difference in evoked potentials across the levels of attentional load. Our findings indicate that in addition to their role in modifying sensory processing, mechanisms of attention can also be a potent modulator of cortical plasticity.

  10. Triglycerides in the Human Kidney Cortex: Relationship with Body Size

    Science.gov (United States)

    Bobulescu, Ion Alexandru; Lotan, Yair; Zhang, Jianning; Rosenthal, Tara R.; Rogers, John T.; Adams-Huet, Beverley; Sakhaee, Khashayar; Moe, Orson W.

    2014-01-01

    Obesity is associated with increased risk for kidney disease and uric acid nephrolithiasis, but the pathophysiological mechanisms underpinning these associations are incompletely understood. Animal experiments have suggested that renal lipid accumulation and lipotoxicity may play a role, but whether lipid accumulation occurs in humans with increasing body mass index (BMI) is unknown. The association between obesity and abnormal triglyceride accumulation in non-adipose tissues (steatosis) has been described in the liver, heart, skeletal muscle and pancreas, but not in the human kidney. We used a quantitative biochemical assay to quantify triglyceride in normal kidney cortex samples from 54 patients undergoing nephrectomy for localized renal cell carcinoma. In subsets of the study population we evaluated the localization of lipid droplets by Oil Red O staining and measured 16 common ceramide species by mass spectrometry. There was a positive correlation between kidney cortex trigyceride content and BMI (Spearman R = 0.27, P = 0.04). Lipid droplets detectable by optical microscopy had a sporadic distribution but were generally more prevalent in individuals with higher BMI, with predominant localization in proximal tubule cells and to a lesser extent in glomeruli. Total ceramide content was inversely correlated with triglycerides. We postulate that obesity is associated with abnormal triglyceride accumulation (steatosis) in the human kidney. In turn, steatosis and lipotoxicity may contribute to the pathogenesis of obesity-associated kidney disease and nephrolithiasis. PMID:25170827

  11. Direction of movement is encoded in the human primary motor cortex.

    Directory of Open Access Journals (Sweden)

    Carolien M Toxopeus

    Full Text Available The present study investigated how direction of hand movement, which is a well-described parameter in cerebral organization of motor control, is incorporated in the somatotopic representation of the manual effector system in the human primary motor cortex (M1. Using functional magnetic resonance imaging (fMRI and a manual step-tracking task we found that activation patterns related to movement in different directions were spatially disjoint within the representation area of the hand on M1. Foci of activation related to specific movement directions were segregated within the M1 hand area; activation related to direction 0° (right was located most laterally/superficially, whereas directions 180° (left and 270° (down elicited activation more medially within the hand area. Activation related to direction 90° was located between the other directions. Moreover, by investigating differences between activations related to movement along the horizontal (0°+180° and vertical (90°+270° axis, we found that activation related to the horizontal axis was located more anterolaterally/dorsally in M1 than for the vertical axis, supporting that activations related to individual movement directions are direction- and not muscle related. Our results of spatially segregated direction-related activations in M1 are in accordance with findings of recent fMRI studies on neural encoding of direction in human M1. Our results thus provide further evidence for a direct link between direction as an organizational principle in sensorimotor transformation and movement execution coded by effector representations in M1.

  12. Contemporary sensorimotor theory

    CERN Document Server

    Martin, Andrew

    2014-01-01

    This book analyzes the philosophical foundations of sensorimotor theory and discusses the most recent applications of sensorimotor theory to human computer interaction, child’s play, virtual reality, robotics, and linguistics. Why does a circle look curved and not angular? Why does red not sound like a bell? Why, as I interact with the world, is there something it is like to be me? An analytic philosopher might suggest: ``if we ponder the concept of circle we find that it is the essence of a circle to be round’’. However, where does this definition come from? Was it set in stone by the Gods, in other words by divine arbiters of circleness, redness and consciousness? Particularly, with regard to visual consciousness, a first attempt to explain why our conscious experience of the world appears as it does has been attributed to Kevin O’Regan and Alva Noe, who published their sensorimotor account of vision and visual consciousness in 2001. Starting with a chapter by Kevin O’Regan, Contemporary Sensorimo...

  13. Human-Derived Disturbance Estimation and Compensation (DEC) Method Lends Itself to a Modular Sensorimotor Control in a Humanoid Robot.

    Science.gov (United States)

    Lippi, Vittorio; Mergner, Thomas

    2017-01-01

    The high complexity of the human posture and movement control system represents challenges for diagnosis, therapy, and rehabilitation of neurological patients. We envisage that engineering-inspired, model-based approaches will help to deal with the high complexity of the human posture control system. Since the methods of system identification and parameter estimation are limited to systems with only a few DoF, our laboratory proposes a heuristic approach that step-by-step increases complexity when creating a hypothetical human-derived control systems in humanoid robots. This system is then compared with the human control in the same test bed, a posture control laboratory. The human-derived control builds upon the identified disturbance estimation and compensation (DEC) mechanism, whose main principle is to support execution of commanded poses or movements by compensating for external or self-produced disturbances such as gravity effects. In previous robotic implementation, up to 3 interconnected DEC control modules were used in modular control architectures separately for the sagittal plane or the frontal body plane and successfully passed balancing and movement tests. In this study we hypothesized that conflict-free movement coordination between the robot's sagittal and frontal body planes emerges simply from the physical embodiment, not necessarily requiring a full body control. Experiments were performed in the 14 DoF robot Lucy Posturob (i) demonstrating that the mechanical coupling from the robot's body suffices to coordinate the controls in the two planes when the robot produces movements and balancing responses in the intermediate plane, (ii) providing quantitative characterization of the interaction dynamics between body planes including frequency response functions (FRFs), as they are used in human postural control analysis, and (iii) witnessing postural and control stability when all DoFs are challenged together with the emergence of inter

  14. Cerebral Microcirculation and Oxygen Tension in the Human Secondary Cortex

    Science.gov (United States)

    Linninger, A. A.; Gould, I. G.; Marinnan, T.; Hsu, C.-Y.; Chojecki, M.; Alaraj, A.

    2013-01-01

    The three-dimensional spatial arrangement of the cortical microcirculatory system is critical for understanding oxygen exchange between blood vessels and brain cells. A three-dimensional computer model of a 3 × 3 × 3 mm3 subsection of the human secondary cortex was constructed to quantify oxygen advection in the microcirculation, tissue oxygen perfusion, and consumption in the human cortex. This computer model accounts for all arterial, capillary and venous blood vessels of the cerebral microvascular bed as well as brain tissue occupying the extravascular space. Microvessels were assembled with optimization algorithms emulating angiogenic growth; a realistic capillary bed was built with space filling procedures. The extravascular tissue was modeled as a porous medium supplied with oxygen by advection–diffusion to match normal metabolic oxygen demand. The resulting synthetic computer generated network matches prior measured morphometrics and fractal patterns of the cortical microvasculature. This morphologically accurate, physiologically consistent, multi-scale computer network of the cerebral microcirculation predicts the oxygen exchange of cortical blood vessels with the surrounding gray matter. Oxygen tension subject to blood pressure and flow conditions were computed and validated for the blood as well as brain tissue. Oxygen gradients along arterioles, capillaries and veins agreed with in vivo trends observed recently in imaging studies within experimental tolerances and uncertainty. PMID:23842693

  15. Temporal Dynamics of Sensorimotor Networks in Effort-Based Cost-Benefit Valuation: Early Emergence and Late Net Value Integration.

    Science.gov (United States)

    Harris, Alison; Lim, Seung-Lark

    2016-07-06

    Although physical effort can impose significant costs on decision-making, when and how effort cost information is incorporated into choice remains contested, reflecting a larger debate over the role of sensorimotor networks in specifying behavior. Serial information processing models, in which motor circuits simply implement the output of cognitive systems, hypothesize that effort cost factors into decisions relatively late, via integration with stimulus values into net (combined) value signals in dorsomedial frontal cortex (dmFC). In contrast, ethology-inspired approaches suggest a more active role for the dorsal sensorimotor stream, with effort cost signals emerging rapidly after stimulus onset. Here we investigated the time course of effort cost integration using event-related potentials in hungry human subjects while they made decisions about expending physical effort for appetitive foods. Consistent with the ethological perspective, we found that effort cost was represented from as early as 100-250 ms after stimulus onset, localized to dorsal sensorimotor regions including middle cingulate, somatosensory, and motor/premotor cortices. However, examining the same data time-locked to motor output revealed net value signals combining stimulus value and effort cost approximately -400 ms before response, originating from sensorimotor areas including dmFC, precuneus, and posterior parietal cortex. Granger causal connectivity analysis of the motor effector signal in the time leading to response showed interactions between these sensorimotor regions and ventrolateral prefrontal cortex, a structure associated with adjusting behavior-response mappings. These results suggest that rapid activation of sensorimotor regions interacts with cognitive valuation systems, producing a net value signal reflecting both physical effort and reward contingencies. Although physical effort imposes a cost on choice, when and how effort cost influences neural correlates of decision

  16. Towards a sensorimotor aesthetics of performing art.

    Science.gov (United States)

    Calvo-Merino, B; Jola, C; Glaser, D E; Haggard, P

    2008-09-01

    The field of neuroaesthetics attempts to identify the brain processes underlying aesthetic experience, including but not limited to beauty. Previous neuroaesthetic studies have focussed largely on paintings and music, while performing arts such as dance have been less studied. Nevertheless, increasing knowledge of the neural mechanisms that represent the bodies and actions of others, and which contribute to empathy, make a neuroaesthetics of dance timely. Here, we present the first neuroscientific study of aesthetic perception in the context of the performing arts. We investigated brain areas whose activity during passive viewing of dance stimuli was related to later, independent aesthetic evaluation of the same stimuli. Brain activity of six naïve male subjects was measured using fMRI, while they watched 24 dance movements, and performed an irrelevant task. In a later session, participants rated each movement along a set of established aesthetic dimensions. The ratings were used to identify brain regions that were more active when viewing moves that received high average ratings than moves that received low average ratings. This contrast revealed bilateral activity in the occipital cortices and in right premotor cortex. Our results suggest a possible role of visual and sensorimotor brain areas in an automatic aesthetic response to dance. This sensorimotor response may explain why dance is widely appreciated in so many human cultures.

  17. Segregation of the human medial prefrontal cortex in social cognition

    Directory of Open Access Journals (Sweden)

    Danilo eBzdok

    2013-05-01

    Full Text Available While the human medial prefrontal cortex (mPFC is widely believed to be a key node of neural networks relevant for socio-emotional processing, its functional subspecialization is still poorly understood. We thus revisited the often assumed differentiation of the mPFC in social cognition along its ventral-dorsal axis. Our neuroinformatic analysis was based on a neuroimaging meta-analysis of perspective-taking that yielded two separate clusters in the ventral and dorsal mPFC, respectively. We determined each seed region’s brain-wide interaction pattern by two complementary measures of functional connectivity: co-activation across a wide range of neuroimaging studies archived in the BrainMap database and correlated signal fluctuations during unconstrained (resting cognition. Furthermore, we characterized the functions associated with these two regions using the BrainMap database. Across methods, the ventral mPFC was more strongly connected with the nucleus accumbens, hippocampus, posterior cingulate cortex, and retrosplenial cortex, while the dorsal mPFC was more strongly connected with the inferior frontal gyrus, temporo-parietal junction, and middle temporal gyrus. Further, the ventral mPFC was selectively associated with action execution, olfaction, and reward related tasks, while the dorsal mPFC was selectively associated with perspective-taking and episodic memory retrieval. The ventral mPFC is therefore predominantly involved in sensory-driven, approach/avoidance-modulating, and evaluation-related processing, whereas the dorsal mPFC is predominantly involved in internally driven, memory-informed, and metacognition-related processing in social cognition.

  18. Characterizing synaptic protein development in human visual cortex enables alignment of synaptic age with rat visual cortex

    Science.gov (United States)

    Pinto, Joshua G. A.; Jones, David G.; Williams, C. Kate; Murphy, Kathryn M.

    2015-01-01

    Although many potential neuroplasticity based therapies have been developed in the lab, few have translated into established clinical treatments for human neurologic or neuropsychiatric diseases. Animal models, especially of the visual system, have shaped our understanding of neuroplasticity by characterizing the mechanisms that promote neural changes and defining timing of the sensitive period. The lack of knowledge about development of synaptic plasticity mechanisms in human cortex, and about alignment of synaptic age between animals and humans, has limited translation of neuroplasticity therapies. In this study, we quantified expression of a set of highly conserved pre- and post-synaptic proteins (Synapsin, Synaptophysin, PSD-95, Gephyrin) and found that synaptic development in human primary visual cortex (V1) continues into late childhood. Indeed, this is many years longer than suggested by neuroanatomical studies and points to a prolonged sensitive period for plasticity in human sensory cortex. In addition, during childhood we found waves of inter-individual variability that are different for the four proteins and include a stage during early development (visual cortex and identified a simple linear equation that provides robust alignment of synaptic age between humans and rats. Alignment of synaptic ages is important for age-appropriate targeting and effective translation of neuroplasticity therapies from the lab to the clinic. PMID:25729353

  19. Optical coherence tomography visualizes neurons in human entorhinal cortex

    Science.gov (United States)

    Magnain, Caroline; Augustinack, Jean C.; Konukoglu, Ender; Frosch, Matthew P.; Sakadžić, Sava; Varjabedian, Ani; Garcia, Nathalie; Wedeen, Van J.; Boas, David A.; Fischl, Bruce

    2015-01-01

    Abstract. The cytoarchitecture of the human brain is of great interest in diverse fields: neuroanatomy, neurology, neuroscience, and neuropathology. Traditional histology is a method that has been historically used to assess cell and fiber content in the ex vivo human brain. However, this technique suffers from significant distortions. We used a previously demonstrated optical coherence microscopy technique to image individual neurons in several square millimeters of en-face tissue blocks from layer II of the human entorhinal cortex, over 50  μm in depth. The same slices were then sectioned and stained for Nissl substance. We registered the optical coherence tomography (OCT) images with the corresponding Nissl stained slices using a nonlinear transformation. The neurons were then segmented in both images and we quantified the overlap. We show that OCT images contain information about neurons that is comparable to what can be obtained from Nissl staining, and thus can be used to assess the cytoarchitecture of the ex vivo human brain with minimal distortion. With the future integration of a vibratome into the OCT imaging rig, this technique can be scaled up to obtain undistorted volumetric data of centimeter cube tissue blocks in the near term, and entire human hemispheres in the future. PMID:25741528

  20. Activation of the insular cortex during dynamic exercise in humans

    DEFF Research Database (Denmark)

    Williamson, James; Nobrega, A C; McColl, R

    1997-01-01

    role as a site for regulation of autonomic activity. 2. Eight subjects were studied during voluntary active cycling and passively induced cycling. Additionally, four of the subjects underwent passive movement combined with electrical stimulation of the legs. 3. Increases in regional cerebral blood flow...... during active, but not passive cycling. There were no significant changes in rCBF for the right insula. Also, the magnitude of rCBF increase for leg primary motor areas was significantly greater for both active cycling and passive cycling combined with electrical stimulation compared with passive cycling...... alone. 5. These findings provide the first evidence of insular activation during dynamic exercise in humans, suggesting that the left insular cortex may serve as a site for cortical regulation of cardiac autonomic (parasympathetic) activity. Additionally, findings during passive cycling with electrical...

  1. Adrenergic receptors in frontal cortex in human brain.

    Science.gov (United States)

    Cash, R; Raisman, R; Ruberg, M; Agid, Y

    1985-02-05

    The binding of three adrenergic ligands ([3H]prazosin, [3H]clonidine, [3H]dihydroalprenolol) was studied in the frontal cortex of human brain. alpha 1-Receptors, labeled by [3H]prazosin, predominated. [3H]Clonidine bound to two classes of sites, one of high affinity and one of low affinity. Guanosine triphosphate appeared to lower the affinity of [3H]clonidine for its receptor. [3H]Dihydroalprenolol bound to three classes of sites: the beta 1-receptor, the beta 2-receptor and a receptor with low affinity which represented about 40% of the total binding, but which was probably a non-specific site; the beta 1/beta 2 ratio was 1/2.

  2. Representation of visual gravitational motion in the human vestibular cortex.

    Science.gov (United States)

    Indovina, Iole; Maffei, Vincenzo; Bosco, Gianfranco; Zago, Myrka; Macaluso, Emiliano; Lacquaniti, Francesco

    2005-04-15

    How do we perceive the visual motion of objects that are accelerated by gravity? We propose that, because vision is poorly sensitive to accelerations, an internal model that calculates the effects of gravity is derived from graviceptive information, is stored in the vestibular cortex, and is activated by visual motion that appears to be coherent with natural gravity. The acceleration of visual targets was manipulated while brain activity was measured using functional magnetic resonance imaging. In agreement with the internal model hypothesis, we found that the vestibular network was selectively engaged when acceleration was consistent with natural gravity. These findings demonstrate that predictive mechanisms of physical laws of motion are represented in the human brain.

  3. Intrinsic frequency biases and profiles across human cortex.

    Science.gov (United States)

    Mellem, Monika S; Wohltjen, Sophie; Gotts, Stephen J; Ghuman, Avniel Singh; Martin, Alex

    2017-11-01

    Recent findings in monkeys suggest that intrinsic periodic spiking activity in selective cortical areas occurs at timescales that follow a sensory or lower order-to-higher order processing hierarchy (Murray JD, Bernacchia A, Freedman DJ, Romo R, Wallis JD, Cai X, Padoa-Schioppa C, Pasternak T, Seo H, Lee D, Wang XJ. Nat Neurosci 17: 1661-1663, 2014). It has not yet been fully explored if a similar timescale hierarchy is present in humans. Additionally, these measures in the monkey studies have not addressed findings that rhythmic activity within a brain area can occur at multiple frequencies. In this study we investigate in humans if regions may be biased toward particular frequencies of intrinsic activity and if a full cortical mapping still reveals an organization that follows this hierarchy. We examined the spectral power in multiple frequency bands (0.5-150 Hz) from task-independent data using magnetoencephalography (MEG). We compared standardized power across bands to find regional frequency biases. Our results demonstrate a mix of lower and higher frequency biases across sensory and higher order regions. Thus they suggest a more complex cortical organization that does not simply follow this hierarchy. Additionally, some regions do not display a bias for a single band, and a data-driven clustering analysis reveals a regional organization with high standardized power in multiple bands. Specifically, theta and beta are both high in dorsal frontal cortex, whereas delta and gamma are high in ventral frontal cortex and temporal cortex. Occipital and parietal regions are biased more narrowly toward alpha power, and ventral temporal lobe displays specific biases toward gamma. Thus intrinsic rhythmic neural activity displays a regional organization but one that is not necessarily hierarchical. NEW & NOTEWORTHY The organization of rhythmic neural activity is not well understood. Whereas it has been postulated that rhythms are organized in a hierarchical manner across

  4. Exon microarray analysis of human dorsolateral prefrontal cortex in alcoholism.

    Science.gov (United States)

    Manzardo, Ann M; Gunewardena, Sumedha; Wang, Kun; Butler, Merlin G

    2014-06-01

    Alcohol abuse is associated with cellular and biochemical disturbances that impact upon protein and nucleic acid synthesis, brain development, function, and behavioral responses. To further characterize the genetic influences in alcoholism and the effects of alcohol consumption on gene expression, we used a highly sensitive exon microarray to examine mRNA expression in human frontal cortex of alcoholics and control males. Messenger RNA was isolated from the dorsolateral prefrontal cortex (dlPFC; Brodmann area 9) of 7 adult alcoholic (6 males, 1 female, mean age 49 years) and 7 matched controls. Affymetrix Human Exon 1.0 ST array was performed according to standard procedures and the results analyzed at the gene level. Microarray findings were validated using quantitative reverse transcription polymerase chain reaction, and the ontology of disturbed genes characterized using Ingenuity Pathway Analysis (IPA). Decreased mRNA expression was observed for genes involved in cellular adhesion (e.g., CTNNA3, ITGA2), transport (e.g., TF, ABCA8), nervous system development (e.g., LRP2, UGT8, GLDN), and signaling (e.g., RASGRP3, LGR5) with influence over lipid and myelin synthesis (e.g., ASPA, ENPP2, KLK6). IPA identified disturbances in network functions associated with neurological disease and development including cellular assembly and organization impacting on psychological disorders. Our data in alcoholism support a reduction in expression of dlPFC mRNA for genes involved with neuronal growth, differentiation, and signaling that targets white matter of the brain. Copyright © 2014 by the Research Society on Alcoholism.

  5. Functional organization and visual representations in human ventral lateral prefrontal cortex

    Directory of Open Access Journals (Sweden)

    Annie Wai Yiu Chan

    2013-07-01

    Full Text Available Recent neuroimaging studies in both human and non-human primates have identified face selective activation in the ventral lateral prefrontal cortex even in the absence of working memory demands. Further, research has suggested that this face-selective response is largely driven by the presence of the eyes. However, the nature and origin of visual category responses in the ventral lateral prefrontal cortex remain unclear. Further, in a broader sense, how do these findings relate to our current understandings of lateral prefrontal cortex? What do these findings tell us about the underlying function and organization principles of the ventral lateral prefrontal cortex? What is the future direction for investigating visual representations in this cortex? This review focuses on the function, topography, and circuitry of the ventral lateral prefrontal cortex to enhance our understanding of the evolution and development of this cortex.

  6. Medial frontal cortex and response conflict: Evidence from human intracranial EEG and medial frontal cortex lesion

    NARCIS (Netherlands)

    Cohen, M.X.; Ridderinkhof, K.R.; Haupt, S.; Elger, C.E.; Fell, J.

    2008-01-01

    The medial frontal cortex (MFC) has been implicated in the monitoring and selection of actions in the face of competing alternatives, but much remains unknown about its functional properties, including electrophysiological oscillations, during response conflict tasks. Here, we recorded intracranial

  7. How does transcranial DC stimulation of the primary motor cortex alter regional neuronal activity in the human brain?

    Science.gov (United States)

    Lang, Nicolas; Siebner, Hartwig R; Ward, Nick S; Lee, Lucy; Nitsche, Michael A; Paulus, Walter; Rothwell, John C; Lemon, Roger N; Frackowiak, Richard S

    2005-07-01

    Transcranial direct current stimulation (tDCS) of the primary motor hand area (M1) can produce lasting polarity-specific effects on corticospinal excitability and motor learning in humans. In 16 healthy volunteers, O positron emission tomography (PET) of regional cerebral blood flow (rCBF) at rest and during finger movements was used to map lasting changes in regional synaptic activity following 10 min of tDCS (+/-1 mA). Bipolar tDCS was given through electrodes placed over the left M1 and right frontopolar cortex. Eight subjects received anodal or cathodal tDCS of the left M1, respectively. When compared to sham tDCS, anodal and cathodal tDCS induced widespread increases and decreases in rCBF in cortical and subcortical areas. These changes in rCBF were of the same magnitude as task-related rCBF changes during finger movements and remained stable throughout the 50-min period of PET scanning. Relative increases in rCBF after real tDCS compared to sham tDCS were found in the left M1, right frontal pole, right primary sensorimotor cortex and posterior brain regions irrespective of polarity. With the exception of some posterior and ventral areas, anodal tDCS increased rCBF in many cortical and subcortical regions compared to cathodal tDCS. Only the left dorsal premotor cortex demonstrated an increase in movement related activity after cathodal tDCS, however, modest compared with the relatively strong movement-independent effects of tDCS. Otherwise, movement related activity was unaffected by tDCS. Our results indicate that tDCS is an effective means of provoking sustained and widespread changes in regional neuronal activity. The extensive spatial and temporal effects of tDCS need to be taken into account when tDCS is used to modify brain function.

  8. Hierarchy of transcriptomic specialization across human cortex captured by myelin map topography

    OpenAIRE

    Murray, John; Martin, William; Bernacchia, Alberto; Anticevic, Alan; Ji, Jie; Navejar, Natasha; Eckner, William; Demirtas, Murat; Burt, Joshua

    2017-01-01

    Hierarchy provides a unifying principle for the macroscale organization of anatomical and functional properties across primate cortex, yet the microscale bases of hierarchical specialization across human cortex are poorly understood. Anatomical hierarchy is conventionally informed by invasively measured laminar patterns of long-range cortico-cortical projections, creating the need for a principled proxy measure of hierarchy in humans. Moreover, cortex exhibits a transcriptional architecture c...

  9. Deactivation in the Sensorimotor Area during Observation of a Human Agent Performing Robotic Actions

    Science.gov (United States)

    Shimada, Sotaro

    2010-01-01

    It is well established that several motor areas, called the mirror-neuron system (MNS), are activated when an individual observes other's actions. However, whether the MNS responds similarly to robotic actions compared with human actions is still controversial. The present study investigated whether and how the motor area activity is influenced by…

  10. Encoding model of temporal processing in human visual cortex.

    Science.gov (United States)

    Stigliani, Anthony; Jeska, Brianna; Grill-Spector, Kalanit

    2017-12-19

    How is temporal information processed in human visual cortex? Visual input is relayed to V1 through segregated transient and sustained channels in the retina and lateral geniculate nucleus (LGN). However, there is intense debate as to how sustained and transient temporal channels contribute to visual processing beyond V1. The prevailing view associates transient processing predominately with motion-sensitive regions and sustained processing with ventral stream regions, while the opposing view suggests that both temporal channels contribute to neural processing beyond V1. Using fMRI, we measured cortical responses to time-varying stimuli and then implemented a two temporal channel-encoding model to evaluate the contributions of each channel. Different from the general linear model of fMRI that predicts responses directly from the stimulus, the encoding approach first models neural responses to the stimulus from which fMRI responses are derived. This encoding approach not only predicts cortical responses to time-varying stimuli from milliseconds to seconds but also, reveals differential contributions of temporal channels across visual cortex. Consistent with the prevailing view, motion-sensitive regions and adjacent lateral occipitotemporal regions are dominated by transient responses. However, ventral occipitotemporal regions are driven by both sustained and transient channels, with transient responses exceeding the sustained. These findings propose a rethinking of temporal processing in the ventral stream and suggest that transient processing may contribute to rapid extraction of the content of the visual input. Importantly, our encoding approach has vast implications, because it can be applied with fMRI to decipher neural computations in millisecond resolution in any part of the brain. Copyright © 2017 the Author(s). Published by PNAS.

  11. Characterizing synaptic protein development in human visual cortex enables alignment of synaptic age with rat visual cortex

    OpenAIRE

    Pinto, Joshua G. A.; Jones, David G.; Williams, C. Kate; Murphy, Kathryn M.

    2015-01-01

    Although many potential neuroplasticity based therapies have been developed in the lab, few have translated into established clinical treatments for human neurologic or neuropsychiatric diseases. Animal models, especially of the visual system, have shaped our understanding of neuroplasticity by characterizing the mechanisms that promote neural changes and defining timing of the sensitive period. The lack of knowledge about development of synaptic plasticity mechanisms in human cortex, and abo...

  12. Characterizing synaptic protein development in human visual cortex enables alignment of synaptic age with rat visual cortex

    OpenAIRE

    Joshua G.A Pinto; David G Jones; Kate eWilliams; Kathryn M Murphy; Kathryn M Murphy

    2015-01-01

    Although many potential neuroplasticity based therapies have been developed in the lab, few have translated into established clinical treatments for human neurologic or neuropsychiatric diseases. Animal models, especially of the visual system, have shaped our understanding of neuroplasticity by characterizing the mechanisms that promote neural changes and defining timing of the sensitive period. The lack of knowledge about development of synaptic plasticity mechanisms in human cortex, and a...

  13. Transcranial focused ultrasound stimulation of human primary visual cortex

    Science.gov (United States)

    Lee, Wonhye; Kim, Hyun-Chul; Jung, Yujin; Chung, Yong An; Song, In-Uk; Lee, Jong-Hwan; Yoo, Seung-Schik

    2016-09-01

    Transcranial focused ultrasound (FUS) is making progress as a new non-invasive mode of regional brain stimulation. Current evidence of FUS-mediated neurostimulation for humans has been limited to the observation of subjective sensory manifestations and electrophysiological responses, thus warranting the identification of stimulated brain regions. Here, we report FUS sonication of the primary visual cortex (V1) in humans, resulting in elicited activation not only from the sonicated brain area, but also from the network of regions involved in visual and higher-order cognitive processes (as revealed by simultaneous acquisition of blood-oxygenation-level-dependent functional magnetic resonance imaging). Accompanying phosphene perception was also reported. The electroencephalo graphic (EEG) responses showed distinct peaks associated with the stimulation. None of the participants showed any adverse effects from the sonication based on neuroimaging and neurological examinations. Retrospective numerical simulation of the acoustic profile showed the presence of individual variability in terms of the location and intensity of the acoustic focus. With exquisite spatial selectivity and capability for depth penetration, FUS may confer a unique utility in providing non-invasive stimulation of region-specific brain circuits for neuroscientific and therapeutic applications.

  14. Aversive learning shapes neuronal orientation tuning in human visual cortex.

    Science.gov (United States)

    McTeague, Lisa M; Gruss, L Forest; Keil, Andreas

    2015-07-28

    The responses of sensory cortical neurons are shaped by experience. As a result perceptual biases evolve, selectively facilitating the detection and identification of sensory events that are relevant for adaptive behaviour. Here we examine the involvement of human visual cortex in the formation of learned perceptual biases. We use classical aversive conditioning to associate one out of a series of oriented gratings with a noxious sound stimulus. After as few as two grating-sound pairings, visual cortical responses to the sound-paired grating show selective amplification. Furthermore, as learning progresses, responses to the orientations with greatest similarity to the sound-paired grating are increasingly suppressed, suggesting inhibitory interactions between orientation-selective neuronal populations. Changes in cortical connectivity between occipital and fronto-temporal regions mirror the changes in visuo-cortical response amplitudes. These findings suggest that short-term behaviourally driven retuning of human visual cortical neurons involves distal top-down projections as well as local inhibitory interactions.

  15. Characterizing synaptic protein development in human visual cortex enables alignment of synaptic age with rat visual cortex

    Directory of Open Access Journals (Sweden)

    Joshua G.A Pinto

    2015-02-01

    Full Text Available Although many potential neuroplasticity based therapies have been developed in the lab, few have translated into established clinical treatments for human neurologic or neuropsychiatric diseases. Animal models, especially of the visual system, have shaped our understanding of neuroplasticity by characterizing the mechanisms that promote neural changes and defining timing of the sensitive period. The lack of knowledge about development of synaptic plasticity mechanisms in human cortex, and about alignment of synaptic age between animals and humans, has limited translation of neuroplasticity therapies. In this study, we quantified expression of a set of highly conserved pre- and post-synaptic proteins (Synapsin, Synaptophysin, PSD-95, Gephyrin and found that synaptic development in human primary visual cortex continues into late childhood. Indeed, this is many years longer than suggested by neuroanatomical studies and points to a prolonged sensitive period for plasticity in human sensory cortex. In addition, during childhood we found waves of inter-individual variability that are different for the 4 proteins and include a stage during early development (<1 year when only Gephyrin has high inter-individual variability. We also found that pre- and post-synaptic protein balances develop quickly, suggesting that maturation of certain synaptic functions happens within the first year or two of life. A multidimensional analysis (principle component analysis showed that most of the variance was captured by the sum of the 4 synaptic proteins. We used that sum to compare development of human and rat visual cortex and identified a simple linear equation that provides robust alignment of synaptic age between humans and rats. Alignment of synaptic ages is important for age-appropriate targeting and effective translation of neuroplasticity therapies from the lab to the clinic.

  16. Mapping visual cortex in monkeys and humans using surface-based atlases

    Science.gov (United States)

    Van Essen, D. C.; Lewis, J. W.; Drury, H. A.; Hadjikhani, N.; Tootell, R. B.; Bakircioglu, M.; Miller, M. I.

    2001-01-01

    We have used surface-based atlases of the cerebral cortex to analyze the functional organization of visual cortex in humans and macaque monkeys. The macaque atlas contains multiple partitioning schemes for visual cortex, including a probabilistic atlas of visual areas derived from a recent architectonic study, plus summary schemes that reflect a combination of physiological and anatomical evidence. The human atlas includes a probabilistic map of eight topographically organized visual areas recently mapped using functional MRI. To facilitate comparisons between species, we used surface-based warping to bring functional and geographic landmarks on the macaque map into register with corresponding landmarks on the human map. The results suggest that extrastriate visual cortex outside the known topographically organized areas is dramatically expanded in human compared to macaque cortex, particularly in the parietal lobe.

  17. Dynamic encoding of speech sequence probability in human temporal cortex.

    Science.gov (United States)

    Leonard, Matthew K; Bouchard, Kristofer E; Tang, Claire; Chang, Edward F

    2015-05-06

    Sensory processing involves identification of stimulus features, but also integration with the surrounding sensory and cognitive context. Previous work in animals and humans has shown fine-scale sensitivity to context in the form of learned knowledge about the statistics of the sensory environment, including relative probabilities of discrete units in a stream of sequential auditory input. These statistics are a defining characteristic of one of the most important sequential signals humans encounter: speech. For speech, extensive exposure to a language tunes listeners to the statistics of sound sequences. To address how speech sequence statistics are neurally encoded, we used high-resolution direct cortical recordings from human lateral superior temporal cortex as subjects listened to words and nonwords with varying transition probabilities between sound segments. In addition to their sensitivity to acoustic features (including contextual features, such as coarticulation), we found that neural responses dynamically encoded the language-level probability of both preceding and upcoming speech sounds. Transition probability first negatively modulated neural responses, followed by positive modulation of neural responses, consistent with coordinated predictive and retrospective recognition processes, respectively. Furthermore, transition probability encoding was different for real English words compared with nonwords, providing evidence for online interactions with high-order linguistic knowledge. These results demonstrate that sensory processing of deeply learned stimuli involves integrating physical stimulus features with their contextual sequential structure. Despite not being consciously aware of phoneme sequence statistics, listeners use this information to process spoken input and to link low-level acoustic representations with linguistic information about word identity and meaning. Copyright © 2015 the authors 0270-6474/15/357203-12$15.00/0.

  18. Connectivity-based parcellation of the human orbitofrontal cortex.

    Science.gov (United States)

    Kahnt, Thorsten; Chang, Luke J; Park, Soyoung Q; Heinzle, Jakob; Haynes, John-Dylan

    2012-05-02

    The primate orbitofrontal cortex (OFC) is involved in reward processing, learning, and decision making. Research in monkeys has shown that this region is densely connected with higher sensory, limbic, and subcortical regions. Moreover, a parcellation of the monkey OFC into two subdivisions has been suggested based on its intrinsic anatomical connections. However, in humans, little is known about any functional subdivisions of the OFC except for a rather coarse medial/lateral distinction. Here, we used resting-state fMRI in combination with unsupervised clustering techniques to investigate whether OFC subdivisions can be revealed based on their functional connectivity profiles with other brain regions. Examination of different cluster solutions provided support for a parcellation into two parts as observed in monkeys, but it also highlighted a much finer hierarchical clustering of the orbital surface. Specifically, we identified (1) a medial, (2) a posterior-central, (3) a central, and (4-6) three lateral clusters spanning the anterior-posterior gradient. Consistent with animal tracing studies, these OFC clusters were connected to other cortical regions such as prefrontal, temporal, and parietal cortices but also subcortical areas in the striatum and the midbrain. These connectivity patterns provide important implications for identifying specific functional roles of OFC subdivisions for reward processing, learning, and decision making. Moreover, this parcellation schema can provide guidance to report results in future studies.

  19. Interaction of streaming and attention in human auditory cortex.

    Science.gov (United States)

    Gutschalk, Alexander; Rupp, André; Dykstra, Andrew R

    2015-01-01

    Serially presented tones are sometimes segregated into two perceptually distinct streams. An ongoing debate is whether this basic streaming phenomenon reflects automatic processes or requires attention focused to the stimuli. Here, we examined the influence of focused attention on streaming-related activity in human auditory cortex using magnetoencephalography (MEG). Listeners were presented with a dichotic paradigm in which left-ear stimuli consisted of canonical streaming stimuli (ABA_ or ABAA) and right-ear stimuli consisted of a classical oddball paradigm. In phase one, listeners were instructed to attend the right-ear oddball sequence and detect rare deviants. In phase two, they were instructed to attend the left ear streaming stimulus and report whether they heard one or two streams. The frequency difference (ΔF) of the sequences was set such that the smallest and largest ΔF conditions generally induced one- and two-stream percepts, respectively. Two intermediate ΔF conditions were chosen to elicit bistable percepts (i.e., either one or two streams). Attention enhanced the peak-to-peak amplitude of the P1-N1 complex, but only for ambiguous ΔF conditions, consistent with the notion that automatic mechanisms for streaming tightly interact with attention and that the latter is of particular importance for ambiguous sound sequences.

  20. Human medial frontal cortex activity predicts learning from errors.

    Science.gov (United States)

    Hester, Robert; Barre, Natalie; Murphy, Kevin; Silk, Tim J; Mattingley, Jason B

    2008-08-01

    Learning from errors is a critical feature of human cognition. It underlies our ability to adapt to changing environmental demands and to tune behavior for optimal performance. The posterior medial frontal cortex (pMFC) has been implicated in the evaluation of errors to control behavior, although it has not previously been shown that activity in this region predicts learning from errors. Using functional magnetic resonance imaging, we examined activity in the pMFC during an associative learning task in which participants had to recall the spatial locations of 2-digit targets and were provided with immediate feedback regarding accuracy. Activity within the pMFC was significantly greater for errors that were subsequently corrected than for errors that were repeated. Moreover, pMFC activity during recall errors predicted future responses (correct vs. incorrect), despite a sizeable interval (on average 70 s) between an error and the next presentation of the same recall probe. Activity within the hippocampus also predicted future performance and correlated with error-feedback-related pMFC activity. A relationship between performance expectations and pMFC activity, in the absence of differing reinforcement value for errors, is consistent with the idea that error-related pMFC activity reflects the extent to which an outcome is "worse than expected."

  1. Hippocampus, Perirhinal Cortex, and Complex Visual Discriminations in Rats and Humans

    Science.gov (United States)

    Hales, Jena B.; Broadbent, Nicola J.; Velu, Priya D.; Squire, Larry R.; Clark, Robert E.

    2015-01-01

    Structures in the medial temporal lobe, including the hippocampus and perirhinal cortex, are known to be essential for the formation of long-term memory. Recent animal and human studies have investigated whether perirhinal cortex might also be important for visual perception. In our study, using a simultaneous oddity discrimination task, rats with…

  2. Reorganization of the Human Somatosensory Cortex in Hand Dystonia

    Directory of Open Access Journals (Sweden)

    Maria Jose Catalan

    2012-05-01

    Full Text Available Background and Purpose: Abnormalities of finger representations in the somatosensory cortex have been identified in patients with focal hand dystonia. Measuring blood flow with positron emission tomography (PET can be use to demonstrate functional localization of receptive fields. Methods: A vibratory stimulus was applied to the right thumb and little finger of six healthy volunteers and six patients with focal hand dystonia to map their receptive fields using H215O PET. Results: The cortical finger representations in the primary somatosensory cortex were closer to each other in patients than in normal subjects. No abnormalities were found in secondary somatosensory cortex, but the somatotopy there is less well distinguished. Conclusions: These data confirm prior electrophysiological and functional neuroimaging observations showing abnormalities of finger representations in somatosensory cortex of patients with focal hand dystonia.

  3. Neural correlates of auditory temporal predictions during sensorimotor synchronization

    Directory of Open Access Journals (Sweden)

    Nadine ePecenka

    2013-08-01

    Full Text Available Musical ensemble performance requires temporally precise interpersonal action coordination. To play in synchrony, ensemble musicians presumably rely on anticipatory mechanisms that enable them to predict the timing of sounds produced by co-performers. Previous studies have shown that individuals differ in their ability to predict upcoming tempo changes in paced finger-tapping tasks (indexed by cross-correlations between tap timing and pacing events and that the degree of such prediction influences the accuracy of sensorimotor synchronization (SMS and interpersonal coordination in dyadic tapping tasks. The current functional magnetic resonance imaging study investigated the neural correlates of auditory temporal predictions during SMS in a within-subject design. Hemodynamic responses were recorded from 18 musicians while they tapped in synchrony with auditory sequences containing gradual tempo changes under conditions of varying cognitive load (achieved by a simultaneous visual n-back working-memory task comprising three levels of difficulty: observation only, 1-back, and 2-back object comparisons. Prediction ability during SMS decreased with increasing cognitive load. Results of a parametric analysis revealed that the generation of auditory temporal predictions during SMS recruits (1 a distributed network in cortico-cerebellar motor-related brain areas (left dorsal premotor and motor cortex, right lateral cerebellum, SMA proper and bilateral inferior parietal cortex and (2 medial cortical areas (medial prefrontal cortex, posterior cingulate cortex. While the first network is presumably involved in basic sensory prediction, sensorimotor integration, motor timing, and temporal adaptation, activation in the second set of areas may be related to higher-level social-cognitive processes elicited during action coordination with auditory signals that resemble music performed by human agents.

  4. Dopamine-dependent changes in the functional connectivity between basal ganglia and cerebral cortex in humans

    NARCIS (Netherlands)

    Williams, D; Tijssen, M; van Bruggen, G; Bosch, A; Insola, A; Di Lazzaro, V; Mazzone, P; Oliviero, A; Quartarone, A; Speelman, H; Brown, P

    2002-01-01

    We test the hypothesis that interaction between the human basal ganglia and cerebral cortex involves activity in multiple functional circuits characterized by their frequency of oscillation, phase characteristics, dopamine dependency and topography. To this end we took recordings from

  5. The Computational Sensorimotor Systems Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Computational Sensorimotor Systems Lab focuses on the exploration, analysis, modeling and implementation of biological sensorimotor systems for both scientific...

  6. Signaling equilibria in sensorimotor interactions.

    Science.gov (United States)

    Leibfried, Felix; Grau-Moya, Jordi; Braun, Daniel A

    2015-08-01

    Although complex forms of communication like human language are often assumed to have evolved out of more simple forms of sensorimotor signaling, less attention has been devoted to investigate the latter. Here, we study communicative sensorimotor behavior of humans in a two-person joint motor task where each player controls one dimension of a planar motion. We designed this joint task as a game where one player (the sender) possesses private information about a hidden target the other player (the receiver) wants to know about, and where the sender's actions are costly signals that influence the receiver's control strategy. We developed a game-theoretic model within the framework of signaling games to investigate whether subjects' behavior could be adequately described by the corresponding equilibrium solutions. The model predicts both separating and pooling equilibria, in which signaling does and does not occur respectively. We observed both kinds of equilibria in subjects and found that, in line with model predictions, the propensity of signaling decreased with increasing signaling costs and decreasing uncertainty on the part of the receiver. Our study demonstrates that signaling games, which have previously been applied to economic decision-making and animal communication, provide a framework for human signaling behavior arising during sensorimotor interactions in continuous and dynamic environments. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Synaptic protein changes after a chronic period of sensorimotor perturbation in adult rats: a potential role of phosphorylation/O-GlcNAcylation interplay.

    Science.gov (United States)

    Fourneau, Julie; Canu, Marie-Hélène; Cieniewski-Bernard, Caroline; Bastide, Bruno; Dupont, Erwan

    2018-05-28

    In human, a chronic sensorimotor perturbation (SMP) through prolonged body immobilization alters motor task performance through a combination of peripheral and central factors. Studies performed on a rat model of SMP have shown biomolecular changes and a reorganization of sensorimotor cortex through events such as morphological modifications of dendritic spines (number, length, functionality). However, underlying mechanisms are still unclear. It is well known that phosphorylation regulates a wide field of synaptic activity leading to neuroplasticity. Another post-translational modification that interplays with phosphorylation is O-GlcNAcylation. This atypical glycosylation, reversible and dynamic, is involved in essential cellular and physiological processes such as synaptic activity, neuronal morphogenesis, learning and memory. We examined potential roles of phosphorylation/O-GlcNAcylation interplay in synaptic plasticity within rat sensorimotor cortex after a SMP period. For this purpose, sensorimotor cortex synaptosomes were separated by sucrose gradient, in order to isolate a subcellular compartment enriched in proteins involved in synaptic functions. A period of SMP induced plastic changes at the pre- and postsynaptic levels, characterized by a reduction of phosphorylation (synapsin1, AMPAR GluA2) and expression (synaptophysin, PSD-95, AMPAR GluA2) of synaptic proteins, as well as a decrease in MAPK/ERK42 activation. Expression levels of OGT/OGA enzymes was unchanged but we observed a specific reduction of synapsin1 O-GlcNAcylation in sensorimotor cortex synaptosomes. The synergistic regulation of synapsin1 phosphorylation/O-GlcNAcylation could affect presynaptic neurotransmitter release. Associated with other pre- and postsynaptic changes, synaptic efficacy could be impaired in somatosensory cortex of SMP rat. Thus, synapsin1 O-GlcNAcylation/phosphorylation interplay also appears to be involved in this synaptic plasticity by finely regulating neural activity

  8. The primary motor and premotor areas of the human cerebral cortex.

    Science.gov (United States)

    Chouinard, Philippe A; Paus, Tomás

    2006-04-01

    Brodmann's cytoarchitectonic map of the human cortex designates area 4 as cortex in the anterior bank of the precentral sulcus and area 6 as cortex encompassing the precentral gyrus and the posterior portion of the superior frontal gyrus on both the lateral and medial surfaces of the brain. More than 70 years ago, Fulton proposed a functional distinction between these two areas, coining the terms primary motor area for cortex in Brodmann area 4 and premotor area for cortex in Brodmann area 6. The parcellation of the cortical motor system has subsequently become more complex. Several nonprimary motor areas have been identified in the brain of the macaque monkey, and associations between anatomy and function in the human brain are being tested continuously using brain mapping techniques. In the present review, the authors discuss the unique properties of the primary motor area (M1), the dorsal portion of the premotor cortex (PMd), and the ventral portion of the premotor cortex (PMv). They end this review by discussing how the premotor areas influence M1.

  9. Is orbital volume associated with eyeball and visual cortex volume in humans?

    Science.gov (United States)

    Pearce, Eiluned; Bridge, Holly

    2013-01-01

    In humans orbital volume increases linearly with absolute latitude. Scaling across mammals between visual system components suggests that these larger orbits should translate into larger eyes and visual cortices in high latitude humans. Larger eyes at high latitudes may be required to maintain adequate visual acuity and enhance visual sensitivity under lower light levels. To test the assumption that orbital volume can accurately index eyeball and visual cortex volumes specifically in humans. Structural Magnetic Resonance Imaging (MRI) techniques are employed to measure eye and orbit (n = 88) and brain and visual cortex (n = 99) volumes in living humans. Facial dimensions and foramen magnum area (a proxy for body mass) were also measured. A significant positive linear relationship was found between (i) orbital and eyeball volumes, (ii) eyeball and visual cortex grey matter volumes and (iii) different visual cortical areas, independently of overall brain volume. In humans the components of the visual system scale from orbit to eye to visual cortex volume independently of overall brain size. These findings indicate that orbit volume can index eye and visual cortex volume in humans, suggesting that larger high latitude orbits do translate into larger visual cortices.

  10. Estimates of segregation and overlap of functional connectivity networks in the human cerebral cortex.

    Science.gov (United States)

    Yeo, B T Thomas; Krienen, Fenna M; Chee, Michael W L; Buckner, Randy L

    2014-03-01

    The organization of the human cerebral cortex has recently been explored using techniques for parcellating the cortex into distinct functionally coupled networks. The divergent and convergent nature of cortico-cortical anatomic connections suggests the need to consider the possibility of regions belonging to multiple networks and hierarchies among networks. Here we applied the Latent Dirichlet Allocation (LDA) model and spatial independent component analysis (ICA) to solve for functionally coupled cerebral networks without assuming that cortical regions belong to a single network. Data analyzed included 1000 subjects from the Brain Genomics Superstruct Project (GSP) and 12 high quality individual subjects from the Human Connectome Project (HCP). The organization of the cerebral cortex was similar regardless of whether a winner-take-all approach or the more relaxed constraints of LDA (or ICA) were imposed. This suggests that large-scale networks may function as partially isolated modules. Several notable interactions among networks were uncovered by the LDA analysis. Many association regions belong to at least two networks, while somatomotor and early visual cortices are especially isolated. As examples of interaction, the precuneus, lateral temporal cortex, medial prefrontal cortex and posterior parietal cortex participate in multiple paralimbic networks that together comprise subsystems of the default network. In addition, regions at or near the frontal eye field and human lateral intraparietal area homologue participate in multiple hierarchically organized networks. These observations were replicated in both datasets and could be detected (and replicated) in individual subjects from the HCP. © 2013.

  11. Functional changes in the human auditory cortex in ageing.

    Directory of Open Access Journals (Sweden)

    Oliver Profant

    Full Text Available Hearing loss, presbycusis, is one of the most common sensory declines in the ageing population. Presbycusis is characterised by a deterioration in the processing of temporal sound features as well as a decline in speech perception, thus indicating a possible central component. With the aim to explore the central component of presbycusis, we studied the function of the auditory cortex by functional MRI in two groups of elderly subjects (>65 years and compared the results with young subjects (cortex. The fMRI showed only minimal activation in response to the 8 kHz stimulation, despite the fact that all subjects heard the stimulus. Both elderly groups showed greater activation in response to acoustical stimuli in the temporal lobes in comparison with young subjects. In addition, activation in the right temporal lobe was more expressed than in the left temporal lobe in both elderly groups, whereas in the young control subjects (YC leftward lateralization was present. No statistically significant differences in activation of the auditory cortex were found between the MP and EP groups. The greater extent of cortical activation in elderly subjects in comparison with young subjects, with an asymmetry towards the right side, may serve as a compensatory mechanism for the impaired processing of auditory information appearing as a consequence of ageing.

  12. Functional Changes in the Human Auditory Cortex in Ageing

    Science.gov (United States)

    Profant, Oliver; Tintěra, Jaroslav; Balogová, Zuzana; Ibrahim, Ibrahim; Jilek, Milan; Syka, Josef

    2015-01-01

    Hearing loss, presbycusis, is one of the most common sensory declines in the ageing population. Presbycusis is characterised by a deterioration in the processing of temporal sound features as well as a decline in speech perception, thus indicating a possible central component. With the aim to explore the central component of presbycusis, we studied the function of the auditory cortex by functional MRI in two groups of elderly subjects (>65 years) and compared the results with young subjects (presbycusis (EP) differed from the elderly group with mild presbycusis (MP) in hearing thresholds measured by pure tone audiometry, presence and amplitudes of transient otoacoustic emissions (TEOAE) and distortion-product oto-acoustic emissions (DPOAE), as well as in speech-understanding under noisy conditions. Acoustically evoked activity (pink noise centered around 350 Hz, 700 Hz, 1.5 kHz, 3 kHz, 8 kHz), recorded by BOLD fMRI from an area centered on Heschl’s gyrus, was used to determine age-related changes at the level of the auditory cortex. The fMRI showed only minimal activation in response to the 8 kHz stimulation, despite the fact that all subjects heard the stimulus. Both elderly groups showed greater activation in response to acoustical stimuli in the temporal lobes in comparison with young subjects. In addition, activation in the right temporal lobe was more expressed than in the left temporal lobe in both elderly groups, whereas in the young control subjects (YC) leftward lateralization was present. No statistically significant differences in activation of the auditory cortex were found between the MP and EP groups. The greater extent of cortical activation in elderly subjects in comparison with young subjects, with an asymmetry towards the right side, may serve as a compensatory mechanism for the impaired processing of auditory information appearing as a consequence of ageing. PMID:25734519

  13. Intraoperative intrinsic optical imaging of human somatosensory cortex during neurosurgical operations.

    Science.gov (United States)

    Sato, Katsushige; Nariai, Tadashi; Momose-Sato, Yoko; Kamino, Kohtaro

    2017-07-01

    Intrinsic optical imaging as developed by Grinvald et al. is a powerful technique for monitoring neural function in the in vivo central nervous system. The advent of this dye-free imaging has also enabled us to monitor human brain function during neurosurgical operations. We briefly describe our own experience in functional mapping of the human somatosensory cortex, carried out using intraoperative optical imaging. The maps obtained demonstrate new additional evidence of a hierarchy for sensory response patterns in the human primary somatosensory cortex.

  14. The Effects of Context and Attention on Spiking Activity in Human Early Visual Cortex

    NARCIS (Netherlands)

    Self, Matthew W.; Peters, Judith C.; Possel, Jessy K.; Reithler, Joel; Goebel, Rainer; Ris, Peterjan; Jeurissen, Danique; Reddy, Leila; Claus, Steven; Baayen, Johannes C.; Roelfsema, Pieter R.

    2016-01-01

    Here we report the first quantitative analysis of spiking activity in human early visual cortex. We recorded multi-unit activity from two electrodes in area V2/V3 of a human patient implanted with depth electrodes as part of her treatment for epilepsy. We observed well-localized multi-unit receptive

  15. The Effects of Context and Attention on Spiking Activity in Human Early Visual Cortex

    NARCIS (Netherlands)

    Self, Matthew W; Peters, Judith C; Possel, Jessy K; Reithler, Joel; Goebel, Rainer; Ris, Peterjan; Jeurissen, Danique; Reddy, Leila; Claus, Steven; Baayen, Johannes C; Roelfsema, Pieter R

    Here we report the first quantitative analysis of spiking activity in human early visual cortex. We recorded multi-unit activity from two electrodes in area V2/V3 of a human patient implanted with depth electrodes as part of her treatment for epilepsy. We observed well-localized multi-unit receptive

  16. Probabilistic tractography recovers a rostrocaudal trajectory of connectivity variability in the human insular cortex

    NARCIS (Netherlands)

    Cerliani, Leonardo; Thomas, Rajat M.; Jbabdi, Saad; Siero, Jeroen C. W.; Nanetti, Luca; Crippa, Alessandro; Gazzola, Valeria; D'Arceuil, Helen; Keysers, Christian

    The insular cortex of macaques has a wide spectrum of anatomical connections whose distribution is related to its heterogeneous cytoarchitecture. Although there is evidence of a similar cytoarchitectural arrangement in humans, the anatomical connectivity of the insula in the human brain has not yet

  17. Human Parahippocampal Cortex Supports Spatial Binding in Visual Working Memory.

    Science.gov (United States)

    Dundon, Neil Michael; Katshu, Mohammad Zia Ul Haq; Harry, Bronson; Roberts, Daniel; Leek, E Charles; Downing, Paul; Sapir, Ayelet; Roberts, Craig; d'Avossa, Giovanni

    2017-09-15

    Studies investigating the functional organization of the medial temporal lobe (MTL) suggest that parahippocampal cortex (PHC) generates representations of spatial and contextual information used by the hippocampus in the formation of episodic memories. However, evidence from animal studies also implicates PHC in spatial binding of visual information held in short term, working memory. Here we examined a 46-year-old man (P.J.), after he had recovered from bilateral medial occipitotemporal cortex strokes resulting in ischemic lesions of PHC and hippocampal atrophy, and a group of age-matched healthy controls. When recalling the color of 1 of 2 objects, P.J. misidentified the target when cued by its location, but not shape. When recalling the position of 1 of 3 objects, he frequently misidentified the target, which was cued by its color. Increasing the duration of the memory delay had no impact on the proportion of binding errors, but did significantly worsen recall precision in both P.J. and controls. We conclude that PHC may play a crucial role in spatial binding during encoding of visual information in working memory. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  18. Exploratory Metabolomic Analyses Reveal Compounds Correlated with Lutein Concentration in Frontal Cortex, Hippocampus, and Occipital Cortex of Human Infant Brain.

    Directory of Open Access Journals (Sweden)

    Jacqueline C Lieblein-Boff

    Full Text Available Lutein is a dietary carotenoid well known for its role as an antioxidant in the macula, and recent reports implicate a role for lutein in cognitive function. Lutein is the dominant carotenoid in both pediatric and geriatric brain tissue. In addition, cognitive function in older adults correlated with macular and postmortem brain lutein concentrations. Furthermore, lutein was found to preferentially accumulate in the infant brain in comparison to other carotenoids that are predominant in diet. While lutein is consistently related to cognitive function, the mechanisms by which lutein may influence cognition are not clear. In an effort to identify potential mechanisms through which lutein might influence neurodevelopment, an exploratory study relating metabolite signatures and lutein was completed. Post-mortem metabolomic analyses were performed on human infant brain tissues in three regions important for learning and memory: the frontal cortex, hippocampus, and occipital cortex. Metabolomic profiles were compared to lutein concentration, and correlations were identified and reported here. A total of 1276 correlations were carried out across all brain regions. Of 427 metabolites analyzed, 257 were metabolites of known identity. Unidentified metabolite correlations (510 were excluded. In addition, moderate correlations with xenobiotic relationships (2 or those driven by single outliers (3 were excluded from further study. Lutein concentrations correlated with lipid pathway metabolites, energy pathway metabolites, brain osmolytes, amino acid neurotransmitters, and the antioxidant homocarnosine. These correlations were often brain region-specific. Revealing relationships between lutein and metabolic pathways may help identify potential candidates on which to complete further analyses and may shed light on important roles of lutein in the human brain during development.

  19. Specific metabolomics adaptations define a differential regional vulnerability in the adult human cerebral cortex

    Directory of Open Access Journals (Sweden)

    Rosanna Cabré

    2016-12-01

    Full Text Available Brain neurons offer diverse responses to stresses and detrimental factors during development and aging, and as a result of both neurodegenerative and neuropsychiatric disorders. This multiplicity of responses can be ascribed to the great diversity among neuronal populations. Here we have determined the metabolomic profile of three healthy adult human brain regions—entorhinal cortex, hippocampus, and frontal cortex—using mass spectrometry-based technologies. Our results show the existence of a lessened energy demand, mitochondrial stress, and lower one-carbon metabolism (particularly restricted to the methionine cycle specifically in frontal cortex. These findings, along with the better antioxidant capacity and lower mTOR signaling also seen in frontal cortex, suggest that this brain region is especially resistant to stress compared to the entorhinal cortex and hippocampus, which are more vulnerable regions. Globally, our results show the presence of specific metabolomics adaptations in three mature, healthy human brain regions, confirming the existence of cross-regional differences in cell vulnerability in the human cerebral cortex.

  20. Functional and structural mapping of human cerebral cortex: solutions are in the surfaces

    Science.gov (United States)

    Van Essen, D. C.; Drury, H. A.; Joshi, S.; Miller, M. I.

    1998-01-01

    The human cerebral cortex is notorious for the depth and irregularity of its convolutions and for its variability from one individual to the next. These complexities of cortical geography have been a chronic impediment to studies of functional specialization in the cortex. In this report, we discuss ways to compensate for the convolutions by using a combination of strategies whose common denominator involves explicit reconstructions of the cortical surface. Surface-based visualization involves reconstructing cortical surfaces and displaying them, along with associated experimental data, in various complementary formats (including three-dimensional native configurations, two-dimensional slices, extensively smoothed surfaces, ellipsoidal representations, and cortical flat maps). Generating these representations for the cortex of the Visible Man leads to a surface-based atlas that has important advantages over conventional stereotaxic atlases as a substrate for displaying and analyzing large amounts of experimental data. We illustrate this by showing the relationship between functionally specialized regions and topographically organized areas in human visual cortex. Surface-based warping allows data to be mapped from individual hemispheres to a surface-based atlas while respecting surface topology, improving registration of identifiable landmarks, and minimizing unwanted distortions. Surface-based warping also can aid in comparisons between species, which we illustrate by warping a macaque flat map to match the shape of a human flat map. Collectively, these approaches will allow more refined analyses of commonalities as well as individual differences in the functional organization of primate cerebral cortex.

  1. Learning-dependent plasticity in human auditory cortex during appetitive operant conditioning.

    Science.gov (United States)

    Puschmann, Sebastian; Brechmann, André; Thiel, Christiane M

    2013-11-01

    Animal experiments provide evidence that learning to associate an auditory stimulus with a reward causes representational changes in auditory cortex. However, most studies did not investigate the temporal formation of learning-dependent plasticity during the task but rather compared auditory cortex receptive fields before and after conditioning. We here present a functional magnetic resonance imaging study on learning-related plasticity in the human auditory cortex during operant appetitive conditioning. Participants had to learn to associate a specific category of frequency-modulated tones with a reward. Only participants who learned this association developed learning-dependent plasticity in left auditory cortex over the course of the experiment. No differential responses to reward predicting and nonreward predicting tones were found in auditory cortex in nonlearners. In addition, learners showed similar learning-induced differential responses to reward-predicting and nonreward-predicting tones in the ventral tegmental area and the nucleus accumbens, two core regions of the dopaminergic neurotransmitter system. This may indicate a dopaminergic influence on the formation of learning-dependent plasticity in auditory cortex, as it has been suggested by previous animal studies. Copyright © 2012 Wiley Periodicals, Inc.

  2. Decoding of faces and face components in face-sensitive human visual cortex

    Directory of Open Access Journals (Sweden)

    David F Nichols

    2010-07-01

    Full Text Available A great challenge to the field of visual neuroscience is to understand how faces are encoded and represented within the human brain. Here we show evidence from functional magnetic resonance imaging (fMRI for spatially distributed processing of the whole face and its components in face-sensitive human visual cortex. We used multi-class linear pattern classifiers constructed with a leave-one-scan-out verification procedure to discriminate brain activation patterns elicited by whole faces, the internal features alone, and the external head outline alone. Furthermore, our results suggest that whole faces are represented disproportionately in the fusiform cortex (FFA whereas the building blocks of faces are represented disproportionately in occipitotemporal cortex (OFA. Faces and face components may therefore be organized with functional clustering within both the FFA and OFA, but with specialization for face components in the OFA and the whole face in the FFA.

  3. The Effects of Context and Attention on Spiking Activity in Human Early Visual Cortex.

    Science.gov (United States)

    Self, Matthew W; Peters, Judith C; Possel, Jessy K; Reithler, Joel; Goebel, Rainer; Ris, Peterjan; Jeurissen, Danique; Reddy, Leila; Claus, Steven; Baayen, Johannes C; Roelfsema, Pieter R

    2016-03-01

    Here we report the first quantitative analysis of spiking activity in human early visual cortex. We recorded multi-unit activity from two electrodes in area V2/V3 of a human patient implanted with depth electrodes as part of her treatment for epilepsy. We observed well-localized multi-unit receptive fields with tunings for contrast, orientation, spatial frequency, and size, similar to those reported in the macaque. We also observed pronounced gamma oscillations in the local-field potential that could be used to estimate the underlying spiking response properties. Spiking responses were modulated by visual context and attention. We observed orientation-tuned surround suppression: responses were suppressed by image regions with a uniform orientation and enhanced by orientation contrast. Additionally, responses were enhanced on regions that perceptually segregated from the background, indicating that neurons in the human visual cortex are sensitive to figure-ground structure. Spiking responses were also modulated by object-based attention. When the patient mentally traced a curve through the neurons' receptive fields, the accompanying shift of attention enhanced neuronal activity. These results demonstrate that the tuning properties of cells in the human early visual cortex are similar to those in the macaque and that responses can be modulated by both contextual factors and behavioral relevance. Our results, therefore, imply that the macaque visual system is an excellent model for the human visual cortex.

  4. The Effects of Context and Attention on Spiking Activity in Human Early Visual Cortex.

    Directory of Open Access Journals (Sweden)

    Matthew W Self

    2016-03-01

    Full Text Available Here we report the first quantitative analysis of spiking activity in human early visual cortex. We recorded multi-unit activity from two electrodes in area V2/V3 of a human patient implanted with depth electrodes as part of her treatment for epilepsy. We observed well-localized multi-unit receptive fields with tunings for contrast, orientation, spatial frequency, and size, similar to those reported in the macaque. We also observed pronounced gamma oscillations in the local-field potential that could be used to estimate the underlying spiking response properties. Spiking responses were modulated by visual context and attention. We observed orientation-tuned surround suppression: responses were suppressed by image regions with a uniform orientation and enhanced by orientation contrast. Additionally, responses were enhanced on regions that perceptually segregated from the background, indicating that neurons in the human visual cortex are sensitive to figure-ground structure. Spiking responses were also modulated by object-based attention. When the patient mentally traced a curve through the neurons' receptive fields, the accompanying shift of attention enhanced neuronal activity. These results demonstrate that the tuning properties of cells in the human early visual cortex are similar to those in the macaque and that responses can be modulated by both contextual factors and behavioral relevance. Our results, therefore, imply that the macaque visual system is an excellent model for the human visual cortex.

  5. The role of human ventral visual cortex in motion perception

    Science.gov (United States)

    Saygin, Ayse P.; Lorenzi, Lauren J.; Egan, Ryan; Rees, Geraint; Behrmann, Marlene

    2013-01-01

    Visual motion perception is fundamental to many aspects of visual perception. Visual motion perception has long been associated with the dorsal (parietal) pathway and the involvement of the ventral ‘form’ (temporal) visual pathway has not been considered critical for normal motion perception. Here, we evaluated this view by examining whether circumscribed damage to ventral visual cortex impaired motion perception. The perception of motion in basic, non-form tasks (motion coherence and motion detection) and complex structure-from-motion, for a wide range of motion speeds, all centrally displayed, was assessed in five patients with a circumscribed lesion to either the right or left ventral visual pathway. Patients with a right, but not with a left, ventral visual lesion displayed widespread impairments in central motion perception even for non-form motion, for both slow and for fast speeds, and this held true independent of the integrity of areas MT/V5, V3A or parietal regions. In contrast with the traditional view in which only the dorsal visual stream is critical for motion perception, these novel findings implicate a more distributed circuit in which the integrity of the right ventral visual pathway is also necessary even for the perception of non-form motion. PMID:23983030

  6. Drawing and writing: An ALE meta-analysis of sensorimotor activations.

    Science.gov (United States)

    Yuan, Ye; Brown, Steven

    2015-08-01

    Drawing and writing are the two major means of creating what are referred to as "images", namely visual patterns on flat surfaces. They share many sensorimotor processes related to visual guidance of hand movement, resulting in the formation of visual shapes associated with pictures and words. However, while the human capacity to draw is tens of thousands of years old, the capacity for writing is only a few thousand years old, and widespread literacy is quite recent. In order to compare the neural activations for drawing and writing, we conducted two activation likelihood estimation (ALE) meta-analyses for these two bodies of neuroimaging literature. The results showed strong overlap in the activation profiles, especially in motor areas (motor cortex, frontal eye fields, supplementary motor area, cerebellum, putamen) and several parts of the posterior parietal cortex. A distinction was found in the left posterior parietal cortex, with drawing showing a preference for a ventral region and writing a dorsal region. These results demonstrate that drawing and writing employ the same basic sensorimotor networks but that some differences exist in parietal areas involved in spatial processing. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Understanding the Dorsal and Ventral Systems of the Human Cerebral Cortex: Beyond Dichotomies

    Science.gov (United States)

    Borst, Gregoire; Thompson, William L.; Kosslyn, Stephen M.

    2011-01-01

    Traditionally, characterizations of the macrolevel functional organization of the human cerebral cortex have focused on the left and right cerebral hemispheres. However, the idea of left brain versus right brain functions has been shown to be an oversimplification. We argue here that a top-bottom divide, rather than a left-right divide, is a more…

  8. Severe cell reduction in the future brain cortex in human growth-restricted fetuses and infants

    DEFF Research Database (Denmark)

    Samuelsen, Grethe B; Pakkenberg, Bente; Bogdanović, Nenad

    2007-01-01

    with controls. The daily increase in brain cells in the future cortex was only half of that of the controls. In the 3 other developmental zones, no significant differences in cell numbers could be demonstrated. CONCLUSIONS: IUGR in humans is associated with a severe reduction in cortical growth...

  9. Type-2 diabetes mellitus reduces cortical thickness and decreases oxidative metabolism in sensorimotor regions after stroke.

    Science.gov (United States)

    Ferris, Jennifer K; Peters, Sue; Brown, Katlyn E; Tourigny, Katherine; Boyd, Lara A

    2018-05-01

    Individuals with type-2 diabetes mellitus experience poor motor outcomes after ischemic stroke. Recent research suggests that type-2 diabetes adversely impacts neuronal integrity and function, yet little work has considered how these neuronal changes affect sensorimotor outcomes after stroke. Here, we considered how type-2 diabetes impacted the structural and metabolic function of the sensorimotor cortex after stroke using volumetric magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS). We hypothesized that the combination of chronic stroke and type-2 diabetes would negatively impact the integrity of sensorimotor cortex as compared to individuals with chronic stroke alone. Compared to stroke alone, individuals with stroke and diabetes had lower cortical thickness bilaterally in the primary somatosensory cortex, and primary and secondary motor cortices. Individuals with stroke and diabetes also showed reduced creatine levels bilaterally in the sensorimotor cortex. Contralesional primary and secondary motor cortex thicknesses were negatively related to sensorimotor outcomes in the paretic upper-limb in the stroke and diabetes group such that those with thinner primary and secondary motor cortices had better motor function. These data suggest that type-2 diabetes alters cerebral energy metabolism, and is associated with thinning of sensorimotor cortex after stroke. These factors may influence motor outcomes after stroke.

  10. The Encoding of Sound Source Elevation in the Human Auditory Cortex.

    Science.gov (United States)

    Trapeau, Régis; Schönwiesner, Marc

    2018-03-28

    Spatial hearing is a crucial capacity of the auditory system. While the encoding of horizontal sound direction has been extensively studied, very little is known about the representation of vertical sound direction in the auditory cortex. Using high-resolution fMRI, we measured voxelwise sound elevation tuning curves in human auditory cortex and show that sound elevation is represented by broad tuning functions preferring lower elevations as well as secondary narrow tuning functions preferring individual elevation directions. We changed the ear shape of participants (male and female) with silicone molds for several days. This manipulation reduced or abolished the ability to discriminate sound elevation and flattened cortical tuning curves. Tuning curves recovered their original shape as participants adapted to the modified ears and regained elevation perception over time. These findings suggest that the elevation tuning observed in low-level auditory cortex did not arise from the physical features of the stimuli but is contingent on experience with spectral cues and covaries with the change in perception. One explanation for this observation may be that the tuning in low-level auditory cortex underlies the subjective perception of sound elevation. SIGNIFICANCE STATEMENT This study addresses two fundamental questions about the brain representation of sensory stimuli: how the vertical spatial axis of auditory space is represented in the auditory cortex and whether low-level sensory cortex represents physical stimulus features or subjective perceptual attributes. Using high-resolution fMRI, we show that vertical sound direction is represented by broad tuning functions preferring lower elevations as well as secondary narrow tuning functions preferring individual elevation directions. In addition, we demonstrate that the shape of these tuning functions is contingent on experience with spectral cues and covaries with the change in perception, which may indicate that the

  11. Plasticity of the human auditory cortex related to musical training.

    Science.gov (United States)

    Pantev, Christo; Herholz, Sibylle C

    2011-11-01

    During the last decades music neuroscience has become a rapidly growing field within the area of neuroscience. Music is particularly well suited for studying neuronal plasticity in the human brain because musical training is more complex and multimodal than most other daily life activities, and because prospective and professional musicians usually pursue the training with high and long-lasting commitment. Therefore, music has increasingly been used as a tool for the investigation of human cognition and its underlying brain mechanisms. Music relates to many brain functions like perception, action, cognition, emotion, learning and memory and therefore music is an ideal tool to investigate how the human brain is working and how different brain functions interact. Novel findings have been obtained in the field of induced cortical plasticity by musical training. The positive effects, which music in its various forms has in the healthy human brain are not only important in the framework of basic neuroscience, but they also will strongly affect the practices in neuro-rehabilitation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. Anatomical segmentation of the human medial prefrontal cortex

    NARCIS (Netherlands)

    Corcoles-Parada, M.; Müller, N.C.J.; Ubero, M.; Serrano-Del-Pueblo, V.M.; Mansilla, F.; Marcos-Rabal, P.; Artacho-Perula, E.; Dresler, M.; Insausti, R.; Fernandez, G.; Munoz-Lopez, M.

    2017-01-01

    The medial prefrontal areas 32, 24, 14, and 25 (mPFC) form part of the limbic memory system, but little is known about their functional specialization in humans. To add anatomical precision to structural and functional magnetic resonance imaging (MRI) data, we aimed to identify these mPFC subareas

  13. Identity-specific coding of future rewards in the human orbitofrontal cortex.

    Science.gov (United States)

    Howard, James D; Gottfried, Jay A; Tobler, Philippe N; Kahnt, Thorsten

    2015-04-21

    Nervous systems must encode information about the identity of expected outcomes to make adaptive decisions. However, the neural mechanisms underlying identity-specific value signaling remain poorly understood. By manipulating the value and identity of appetizing food odors in a pattern-based imaging paradigm of human classical conditioning, we were able to identify dissociable predictive representations of identity-specific reward in orbitofrontal cortex (OFC) and identity-general reward in ventromedial prefrontal cortex (vmPFC). Reward-related functional coupling between OFC and olfactory (piriform) cortex and between vmPFC and amygdala revealed parallel pathways that support identity-specific and -general predictive signaling. The demonstration of identity-specific value representations in OFC highlights a role for this region in model-based behavior and reveals mechanisms by which appetitive behavior can go awry.

  14. Frequency-Selective Attention in Auditory Scenes Recruits Frequency Representations Throughout Human Superior Temporal Cortex.

    Science.gov (United States)

    Riecke, Lars; Peters, Judith C; Valente, Giancarlo; Kemper, Valentin G; Formisano, Elia; Sorger, Bettina

    2017-05-01

    A sound of interest may be tracked amid other salient sounds by focusing attention on its characteristic features including its frequency. Functional magnetic resonance imaging findings have indicated that frequency representations in human primary auditory cortex (AC) contribute to this feat. However, attentional modulations were examined at relatively low spatial and spectral resolutions, and frequency-selective contributions outside the primary AC could not be established. To address these issues, we compared blood oxygenation level-dependent (BOLD) responses in the superior temporal cortex of human listeners while they identified single frequencies versus listened selectively for various frequencies within a multifrequency scene. Using best-frequency mapping, we observed that the detailed spatial layout of attention-induced BOLD response enhancements in primary AC follows the tonotopy of stimulus-driven frequency representations-analogous to the "spotlight" of attention enhancing visuospatial representations in retinotopic visual cortex. Moreover, using an algorithm trained to discriminate stimulus-driven frequency representations, we could successfully decode the focus of frequency-selective attention from listeners' BOLD response patterns in nonprimary AC. Our results indicate that the human brain facilitates selective listening to a frequency of interest in a scene by reinforcing the fine-grained activity pattern throughout the entire superior temporal cortex that would be evoked if that frequency was present alone. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  15. Optical properties of the medulla and the cortex of human scalp hair

    Science.gov (United States)

    Kharin, Aleksey; Varghese, Babu; Verhagen, Rieko; Uzunbajakava, Natallia

    2009-03-01

    An increasing number of applications, including non- or minimally invasive diagnostics and treatment as well as various cosmetic procedures, has resulted in a need to determine the optical properties of hair and its structures. We report on the measurement of the total attenuation coefficient of the cortex and the medulla of blond, gray, and Asian black human scalp hair at a 633-nm wavelength. Our results show that for blond and gray hair the total attenuation coefficient of the medulla is more than 200 times higher compared to that of the cortex. This difference is only 1.5 times for Asian black hair. Furthermore, we present the total attenuation coefficient of the cortex of blond, gray, light brown, and Asian black hair measured at wavelengths of 409, 532, 633, 800, and 1064 nm. The total attenuation coefficient consistently decreases with an increase in wavelength, as well as with a decrease in hair pigmentation. Additionally, we demonstrate the dependence of the total attenuation coefficient of the cortex and the medulla of Asian black hair on the polarization of incident light. A similar dependence is observed for the cortex of blond and gray hair but not for the medulla of these hair types.

  16. The neural dynamics of reward value and risk coding in the human orbitofrontal cortex.

    Science.gov (United States)

    Li, Yansong; Vanni-Mercier, Giovanna; Isnard, Jean; Mauguière, François; Dreher, Jean-Claude

    2016-04-01

    The orbitofrontal cortex is known to carry information regarding expected reward, risk and experienced outcome. Yet, due to inherent limitations in lesion and neuroimaging methods, the neural dynamics of these computations has remained elusive in humans. Here, taking advantage of the high temporal definition of intracranial recordings, we characterize the neurophysiological signatures of the intact orbitofrontal cortex in processing information relevant for risky decisions. Local field potentials were recorded from the intact orbitofrontal cortex of patients suffering from drug-refractory partial epilepsy with implanted depth electrodes as they performed a probabilistic reward learning task that required them to associate visual cues with distinct reward probabilities. We observed three successive signals: (i) around 400 ms after cue presentation, the amplitudes of the local field potentials increased with reward probability; (ii) a risk signal emerged during the late phase of reward anticipation and during the outcome phase; and (iii) an experienced value signal appeared at the time of reward delivery. Both the medial and lateral orbitofrontal cortex encoded risk and reward probability while the lateral orbitofrontal cortex played a dominant role in coding experienced value. The present study provides the first evidence from intracranial recordings that the human orbitofrontal cortex codes reward risk both during late reward anticipation and during the outcome phase at a time scale of milliseconds. Our findings offer insights into the rapid mechanisms underlying the ability to learn structural relationships from the environment. © The Author (2016). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. Intonational speech prosody encoding in the human auditory cortex.

    Science.gov (United States)

    Tang, C; Hamilton, L S; Chang, E F

    2017-08-25

    Speakers of all human languages regularly use intonational pitch to convey linguistic meaning, such as to emphasize a particular word. Listeners extract pitch movements from speech and evaluate the shape of intonation contours independent of each speaker's pitch range. We used high-density electrocorticography to record neural population activity directly from the brain surface while participants listened to sentences that varied in intonational pitch contour, phonetic content, and speaker. Cortical activity at single electrodes over the human superior temporal gyrus selectively represented intonation contours. These electrodes were intermixed with, yet functionally distinct from, sites that encoded different information about phonetic features or speaker identity. Furthermore, the representation of intonation contours directly reflected the encoding of speaker-normalized relative pitch but not absolute pitch. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  18. Transcranial alternating current stimulation at beta frequency: lack of immediate effects on excitation and interhemispheric inhibition of the human motor cortex

    Directory of Open Access Journals (Sweden)

    Viola Rjosk

    2016-11-01

    Full Text Available Transcranial alternating current stimulation (tACS is a form of noninvasive brain stimulation and is capable of influencing brain oscillations and cortical networks. In humans, the endogenous oscillation frequency in sensorimotor areas peaks at 20 Hz. This beta-band typically occurs during maintenance of tonic motor output and seems to play a role in interhemispheric coordination of movements. Previous studies showed that tACS applied in specific frequency bands over primary motor cortex (M1 or the visual cortex modulates cortical excitability within the stimulated hemisphere. However, the particular impact remains controversial because effects of tACS were shown to be frequency, duration and location specific. Furthermore, the potential of tACS to modulate cortical interhemispheric processing, like interhemispheric inhibition (IHI, remains elusive. Transcranial magnetic stimulation (TMS is a noninvasive and well-tolerated method of directly activating neurons in superficial areas of the human brain and thereby a useful tool for evaluating the functional state of motor pathways. The aim of the present study was to elucidate the immediate effect of 10 min tACS in the β-frequency band (20 Hz over left M1 on IHI between M1s in 19 young, healthy, right-handed participants. A series of TMS measurements (MEP size, RMT, IHI from left to right M1 and vice versa was performed before and immediately after tACS or sham using a double-blinded, cross-over design. We did not find any significant tACS-induced modulations of intracortical excitation (as assessed by MEP size and RMT and/or interhemispheric inhibition (IHI. These results indicate that 10 min of 20 Hz tACS over left M1 seems incapable of modulating immediate brain activity or inhibition. Further studies are needed to elucidate potential aftereffects of 20 Hz tACS as well as frequency-specific effects of tACS on intracortical excitation and interhemispheric inhibition.

  19. The Representation of Object Viewpoint in Human Visual Cortex

    OpenAIRE

    Andresen, David R.; Vinberg, Joakim; Grill-Spector, Kalanit

    2008-01-01

    Understanding the nature of object representations in the human brain is critical for understanding the neural basis of invariant object recognition. However, the degree to which object representations are sensitive to object viewpoint is unknown. Using fMRI we employed a parametric approach to examine the sensitivity to object view as a function of rotation (0°–180°), category (animal/vehicle) and fMRI-adaptation paradigm (short or long-lagged). For both categories and fMRI-adaptation paradi...

  20. Timing, timing, timing: Fast decoding of object information from intracranial field potentials in human visual cortex

    Science.gov (United States)

    Liu, Hesheng; Agam, Yigal; Madsen, Joseph R.; Kreiman, Gabriel

    2010-01-01

    Summary The difficulty of visual recognition stems from the need to achieve high selectivity while maintaining robustness to object transformations within hundreds of milliseconds. Theories of visual recognition differ in whether the neuronal circuits invoke recurrent feedback connections or not. The timing of neurophysiological responses in visual cortex plays a key role in distinguishing between bottom-up and top-down theories. Here we quantified at millisecond resolution the amount of visual information conveyed by intracranial field potentials from 912 electrodes in 11 human subjects. We could decode object category information from human visual cortex in single trials as early as 100 ms post-stimulus. Decoding performance was robust to depth rotation and scale changes. The results suggest that physiological activity in the temporal lobe can account for key properties of visual recognition. The fast decoding in single trials is compatible with feed-forward theories and provides strong constraints for computational models of human vision. PMID:19409272

  1. GABAA receptor subunit gene expression in human prefrontal cortex: comparison of schizophrenics and controls

    Science.gov (United States)

    Akbarian, S.; Huntsman, M. M.; Kim, J. J.; Tafazzoli, A.; Potkin, S. G.; Bunney, W. E. Jr; Jones, E. G.; Bloom, F. E. (Principal Investigator)

    1995-01-01

    The prefrontal cortex of schizophrenics is hypoactive and displays changes related to inhibitory, GABAergic neurons, and GABAergic synapses. These changes include decreased levels of glutamic acid decarboxylase (GAD), the enzyme for GABA synthesis, upregulation of muscimol binding, and downregulation of benzodiazepine binding to GABAA receptors. Studies in the visual cortex of nonhuman primates have demonstrated that gene expression for GAD and for several GABAA receptor subunit polypeptides is under control of neuronal activity, raising the possibility that similar mechanisms in the hypoactive prefrontal cortex of schizophrenics may explain the abnormalities in GAD and in GABAA receptor regulation. In the present study, which is the first of its type on human cerebral cortex, levels of mRNAs for six GABAA receptor subunits (alpha 1, alpha 2, alpha 5, beta 1, beta 2, gamma 2) and their laminar expression patterns were analyzed in the prefrontal cortex of schizophrenics and matched controls, using in situ hybridization histochemistry and densitometry. Three types of laminar expression pattern were observed: mRNAs for the alpha 1, beta 2, and gamma 2 subunits, which are the predominant receptor subunits expressed in the mature cortex, were expressed at comparatively high levels by cells of all six cortical layers, but most intensely by cells in lower layer III and layer IV. mRNAs for the alpha 2, alpha 5, and beta 1 subunits were expressed at lower levels; alpha 2 and beta 1 were expressed predominantly by cells in layers II, III, and IV; alpha 5 was expressed predominantly in layers IV, V, and VI. There were no significant changes in overall mRNA levels for any of the receptor subunits in the prefrontal cortex of schizophrenics, and the laminar expression pattern of all six receptor subunit mRNAs did not differ between schizophrenics and controls. Because gene expression for GABAA receptor subunits is not consistently altered in the prefrontal cortex of

  2. Intracerebral evidence of rhythm transform in the human auditory cortex.

    Science.gov (United States)

    Nozaradan, Sylvie; Mouraux, André; Jonas, Jacques; Colnat-Coulbois, Sophie; Rossion, Bruno; Maillard, Louis

    2017-07-01

    Musical entrainment is shared by all human cultures and the perception of a periodic beat is a cornerstone of this entrainment behavior. Here, we investigated whether beat perception might have its roots in the earliest stages of auditory cortical processing. Local field potentials were recorded from 8 patients implanted with depth-electrodes in Heschl's gyrus and the planum temporale (55 recording sites in total), usually considered as human primary and secondary auditory cortices. Using a frequency-tagging approach, we show that both low-frequency (30 Hz) neural activities in these structures faithfully track auditory rhythms through frequency-locking to the rhythm envelope. A selective gain in amplitude of the response frequency-locked to the beat frequency was observed for the low-frequency activities but not for the high-frequency activities, and was sharper in the planum temporale, especially for the more challenging syncopated rhythm. Hence, this gain process is not systematic in all activities produced in these areas and depends on the complexity of the rhythmic input. Moreover, this gain was disrupted when the rhythm was presented at fast speed, revealing low-pass response properties which could account for the propensity to perceive a beat only within the musical tempo range. Together, these observations show that, even though part of these neural transforms of rhythms could already take place in subcortical auditory processes, the earliest auditory cortical processes shape the neural representation of rhythmic inputs in favor of the emergence of a periodic beat.

  3. Cross-population myelination covariance of human cerebral cortex.

    Science.gov (United States)

    Ma, Zhiwei; Zhang, Nanyin

    2017-09-01

    Cross-population covariance of brain morphometric quantities provides a measure of interareal connectivity, as it is believed to be determined by the coordinated neurodevelopment of connected brain regions. Although useful, structural covariance analysis predominantly employed bulky morphological measures with mixed compartments, whereas studies of the structural covariance of any specific subdivisions such as myelin are rare. Characterizing myelination covariance is of interest, as it will reveal connectivity patterns determined by coordinated development of myeloarchitecture between brain regions. Using myelin content MRI maps from the Human Connectome Project, here we showed that the cortical myelination covariance was highly reproducible, and exhibited a brain organization similar to that previously revealed by other connectivity measures. Additionally, the myelination covariance network shared common topological features of human brain networks such as small-worldness. Furthermore, we found that the correlation between myelination covariance and resting-state functional connectivity (RSFC) was uniform within each resting-state network (RSN), but could considerably vary across RSNs. Interestingly, this myelination covariance-RSFC correlation was appreciably stronger in sensory and motor networks than cognitive and polymodal association networks, possibly due to their different circuitry structures. This study has established a new brain connectivity measure specifically related to axons, and this measure can be valuable to investigating coordinated myeloarchitecture development. Hum Brain Mapp 38:4730-4743, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  4. Saturation in Phosphene Size with Increasing Current Levels Delivered to Human Visual Cortex.

    Science.gov (United States)

    Bosking, William H; Sun, Ping; Ozker, Muge; Pei, Xiaomei; Foster, Brett L; Beauchamp, Michael S; Yoshor, Daniel

    2017-07-26

    Electrically stimulating early visual cortex results in a visual percept known as a phosphene. Although phosphenes can be evoked by a wide range of electrode sizes and current amplitudes, they are invariably described as small. To better understand this observation, we electrically stimulated 93 electrodes implanted in the visual cortex of 13 human subjects who reported phosphene size while stimulation current was varied. Phosphene size increased as the stimulation current was initially raised above threshold, but then rapidly reached saturation. Phosphene size also depended on the location of the stimulated site, with size increasing with distance from the foveal representation. We developed a model relating phosphene size to the amount of activated cortex and its location within the retinotopic map. First, a sigmoidal curve was used to predict the amount of activated cortex at a given current. Second, the amount of active cortex was converted to degrees of visual angle by multiplying by the inverse cortical magnification factor for that retinotopic location. This simple model accurately predicted phosphene size for a broad range of stimulation currents and cortical locations. The unexpected saturation in phosphene sizes suggests that the functional architecture of cerebral cortex may impose fundamental restrictions on the spread of artificially evoked activity and this may be an important consideration in the design of cortical prosthetic devices. SIGNIFICANCE STATEMENT Understanding the neural basis for phosphenes, the visual percepts created by electrical stimulation of visual cortex, is fundamental to the development of a visual cortical prosthetic. Our experiments in human subjects implanted with electrodes over visual cortex show that it is the activity of a large population of cells spread out across several millimeters of tissue that supports the perception of a phosphene. In addition, we describe an important feature of the production of phosphenes by

  5. Structural and functional analyses of human cerebral cortex using a surface-based atlas

    Science.gov (United States)

    Van Essen, D. C.; Drury, H. A.

    1997-01-01

    We have analyzed the geometry, geography, and functional organization of human cerebral cortex using surface reconstructions and cortical flat maps of the left and right hemispheres generated from a digital atlas (the Visible Man). The total surface area of the reconstructed Visible Man neocortex is 1570 cm2 (both hemispheres), approximately 70% of which is buried in sulci. By linking the Visible Man cerebrum to the Talairach stereotaxic coordinate space, the locations of activation foci reported in neuroimaging studies can be readily visualized in relation to the cortical surface. The associated spatial uncertainty was empirically shown to have a radius in three dimensions of approximately 10 mm. Application of this approach to studies of visual cortex reveals the overall patterns of activation associated with different aspects of visual function and the relationship of these patterns to topographically organized visual areas. Our analysis supports a distinction between an anterior region in ventral occipito-temporal cortex that is selectively involved in form processing and a more posterior region (in or near areas VP and V4v) involved in both form and color processing. Foci associated with motion processing are mainly concentrated in a region along the occipito-temporal junction, the ventral portion of which overlaps with foci also implicated in form processing. Comparisons between flat maps of human and macaque monkey cerebral cortex indicate significant differences as well as many similarities in the relative sizes and positions of cortical regions known or suspected to be homologous in the two species.

  6. Functional magnetic resonance imaging of the human primary visual cortex during visual stimulation

    International Nuclear Information System (INIS)

    Miki, Atsushi; Abe, Haruki; Nakajima, Takashi; Fujita, Motoi; Watanabe, Hiroyuki; Kuwabara, Takeo; Naruse, Shoji; Takagi, Mineo.

    1995-01-01

    Signal changes in the human primary visual cortex during visual stimulation were evaluated using non-invasive functional magnetic resonance imaging (fMRI). The experiments were performed on 10 normal human volunteers and 2 patients with homonymous hemianopsia, including one who was recovering from the exacerbation of multiple sclerosis. The visual stimuli were provided by a pattern generator using the checkerboard pattern for determining the visual evoked potential of full-field and hemifield stimulation. In normal volunteers, a signal increase was observed on the bilateral primary visual cortex during the full-field stimulation and on the contra-lateral cortex during hemifield stimulation. In the patient with homonymous hemianopsia after cerebral infarction, the signal change was clearly decreased on the affected side. In the other patient, the one recovering from multiple sclerosis with an almost normal visual field, the fMRI was within normal limits. These results suggest that it is possible to visualize the activation of the visual cortex during visual stimulation, and that there is a possibility of using this test as an objective method of visual field examination. (author)

  7. Developmental changes in GABAergic mechanisms in human visual cortex across the lifespan

    Directory of Open Access Journals (Sweden)

    Joshua G A Pinto

    2010-06-01

    Full Text Available Functional maturation of visual cortex is linked with dynamic changes in synaptic expression of GABAergic mechanisms. These include setting the excitation-inhibition balance required for experience-dependent plasticity, as well as, intracortical inhibition underlying development and aging of receptive field properties. Animal studies have shown developmental regulation of GABAergic mechanisms in visual cortex. In this study, we show for the first time how these mechanisms develop in the human visual cortex across the lifespan. We used Western blot analysis of postmortem tissue from human primary visual cortex (n=30, range: 20 days to 80 years to quantify expression of 8 pre- and post-synaptic GABAergic markers. We quantified the inhibitory modulating cannabinoid receptor (CB1, GABA vesicular transporter (VGAT, GABA synthesizing enzymes (GAD65/GAD67, GABAA receptor anchoring protein (Gephyrin, and GABAA receptor subunits (GABAA∝1, GABAA∝2, GABAA∝3. We found a complex pattern of changes, many of which were prolonged and continued well into into the teen, young adult, and even older adult years. These included a monotonic increase or decrease (GABAA∝1, GABAA∝2, a biphasic increase then decrease (GAD65, Gephyrin, or multiple increases and decreases (VGAT, CB1 across the lifespan. Comparing the balances between the pre- and post-synaptic markers we found 3 main transitions (early childhood, early teen years, aging when there were rapid switches in the composition of the GABAergic signaling system, indicating that functioning of the GABAergic system must change as the visual cortex develops and ages. Furthermore, these results provide key information for translating therapies developed in animal models into effective treatments for amblyopia in humans.

  8. The bilingual brain: Flexibility and control in the human cortex

    Science.gov (United States)

    Buchweitz, Augusto; Prat, Chantel

    2013-12-01

    The goal of the present review is to discuss recent cognitive neuroscientific findings concerning bilingualism. Three interrelated questions about the bilingual brain are addressed: How are multiple languages represented in the brain? how are languages controlled in the brain? and what are the real-world implications of experience with multiple languages? The review is based on neuroimaging research findings about the nature of bilingual processing, namely, how the brain adapts to accommodate multiple languages in the bilingual brain and to control which language should be used, and when. We also address how this adaptation results in differences observed in the general cognition of bilingual individuals. General implications for models of human learning, plasticity, and cognitive control are discussed.

  9. APP Metabolism Regulates Tau Proteostasis in Human Cerebral Cortex Neurons

    Directory of Open Access Journals (Sweden)

    Steven Moore

    2015-05-01

    Full Text Available Accumulation of Aβ peptide fragments of the APP protein and neurofibrillary tangles of the microtubule-associated protein tau are the cellular hallmarks of Alzheimer’s disease (AD. To investigate the relationship between APP metabolism and tau protein levels and phosphorylation, we studied human-stem-cell-derived forebrain neurons with genetic forms of AD, all of which increase the release of pathogenic Aβ peptides. We identified marked increases in intracellular tau in genetic forms of AD that either mutated APP or increased its dosage, suggesting that APP metabolism is coupled to changes in tau proteostasis. Manipulating APP metabolism by β-secretase and γ-secretase inhibition, as well as γ-secretase modulation, results in specific increases and decreases in tau protein levels. These data demonstrate that APP metabolism regulates tau proteostasis and suggest that the relationship between APP processing and tau is not mediated solely through extracellular Aβ signaling to neurons.

  10. The representation of object viewpoint in human visual cortex.

    Science.gov (United States)

    Andresen, David R; Vinberg, Joakim; Grill-Spector, Kalanit

    2009-04-01

    Understanding the nature of object representations in the human brain is critical for understanding the neural basis of invariant object recognition. However, the degree to which object representations are sensitive to object viewpoint is unknown. Using fMRI we employed a parametric approach to examine the sensitivity to object view as a function of rotation (0 degrees-180 degrees ), category (animal/vehicle) and fMRI-adaptation paradigm (short or long-lagged). For both categories and fMRI-adaptation paradigms, object-selective regions recovered from adaptation when a rotated view of an object was shown after adaptation to a specific view of that object, suggesting that representations are sensitive to object rotation. However, we found evidence for differential representations across categories and ventral stream regions. Rotation cross-adaptation was larger for animals than vehicles, suggesting higher sensitivity to vehicle than animal rotation, and was largest in the left fusiform/occipito-temporal sulcus (pFUS/OTS), suggesting that this region has low sensitivity to rotation. Moreover, right pFUS/OTS and FFA responded more strongly to front than back views of animals (without adaptation) and rotation cross-adaptation depended both on the level of rotation and the adapting view. This result suggests a prevalence of neurons that prefer frontal views of animals in fusiform regions. Using a computational model of view-tuned neurons, we demonstrate that differential neural view tuning widths and relative distributions of neural-tuned populations in fMRI voxels can explain the fMRI results. Overall, our findings underscore the utility of parametric approaches for studying the neural basis of object invariance and suggest that there is no complete invariance to object view in the human ventral stream.

  11. Human Motor Cortex Functional Changes in Acute Stroke: Gender Effects

    Directory of Open Access Journals (Sweden)

    Vincenzo eDi Lazzaro

    2016-01-01

    Full Text Available The acute phase of stroke is accompanied by functional changes in the activity and interplay of both hemispheres. In healthy subjects, gender is known to impact the functional brain organization.We investigated whether gender influences also acute stroke functional changes. In thirty-five ischemic stroke patients, we evaluated the excitability of the affected (AH and unaffected hemisphere (UH by measuring resting and active motor threshold and motor-evoked potential amplitude under baseline conditions and after intermittent theta burst stimulation (iTBS of AH. We also computed an index of the excitability balance between the hemispheres, laterality indexes (LI, to evidence hemispheric asymmetry. Active motor threshold differed significantly between AH and UH only in the male group (p=0.004, not in females (p>0.200, and both LIAMT and LIRMT were significantly higher in males than in females (respectively p=0.033 and p=0.042. LTP-like activity induced by iTBS in AH was more frequent in females. Gender influences the functional excitability changes that take place after human stroke and the level of LTP that can be induced by repetitive stimulation. This knowledge is of high value in the attempt of individualizing to different genders any non-invasive stimulation strategy designed to foster stroke recovery.

  12. Human Motor Cortex Functional Changes in Acute Stroke: Gender Effects

    Science.gov (United States)

    Di Lazzaro, Vincenzo; Pellegrino, Giovanni; Di Pino, Giovanni; Ranieri, Federico; Lotti, Fiorenza; Florio, Lucia; Capone, Fioravante

    2016-01-01

    The acute phase of stroke is accompanied by functional changes in the activity and interplay of both hemispheres. In healthy subjects, gender is known to impact the functional brain organization. We investigated whether gender influences also acute stroke functional changes. In thirty-five ischemic stroke patients, we evaluated the excitability of the affected (AH) and unaffected hemisphere (UH) by measuring resting and active motor threshold (AMT) and motor-evoked potential amplitude under baseline conditions and after intermittent theta burst stimulation (iTBS) of AH. We also computed an index of the excitability balance between the hemispheres, laterality indexes (LI), to evidence hemispheric asymmetry. AMT differed significantly between AH and UH only in the male group (p = 0.004), not in females (p > 0.200), and both LIAMT and LIRMT were significantly higher in males than in females (respectively p = 0.033 and p = 0.042). LTP-like activity induced by iTBS in AH was more frequent in females. Gender influences the functional excitability changes that take place after human stroke and the level of LTP that can be induced by repetitive stimulation. This knowledge is of high value in the attempt of individualizing to different genders any non-invasive stimulation strategy designed to foster stroke recovery. PMID:26858590

  13. APP metabolism regulates tau proteostasis in human cerebral cortex neurons.

    Science.gov (United States)

    Moore, Steven; Evans, Lewis D B; Andersson, Therese; Portelius, Erik; Smith, James; Dias, Tatyana B; Saurat, Nathalie; McGlade, Amelia; Kirwan, Peter; Blennow, Kaj; Hardy, John; Zetterberg, Henrik; Livesey, Frederick J

    2015-05-05

    Accumulation of Aβ peptide fragments of the APP protein and neurofibrillary tangles of the microtubule-associated protein tau are the cellular hallmarks of Alzheimer's disease (AD). To investigate the relationship between APP metabolism and tau protein levels and phosphorylation, we studied human-stem-cell-derived forebrain neurons with genetic forms of AD, all of which increase the release of pathogenic Aβ peptides. We identified marked increases in intracellular tau in genetic forms of AD that either mutated APP or increased its dosage, suggesting that APP metabolism is coupled to changes in tau proteostasis. Manipulating APP metabolism by β-secretase and γ-secretase inhibition, as well as γ-secretase modulation, results in specific increases and decreases in tau protein levels. These data demonstrate that APP metabolism regulates tau proteostasis and suggest that the relationship between APP processing and tau is not mediated solely through extracellular Aβ signaling to neurons. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  14. Anodal transcranial direct current stimulation reduces psychophysically measured surround suppression in the human visual cortex.

    Directory of Open Access Journals (Sweden)

    Daniel P Spiegel

    Full Text Available Transcranial direct current stimulation (tDCS is a safe, non-invasive technique for transiently modulating the balance of excitation and inhibition within the human brain. It has been reported that anodal tDCS can reduce both GABA mediated inhibition and GABA concentration within the human motor cortex. As GABA mediated inhibition is thought to be a key modulator of plasticity within the adult brain, these findings have broad implications for the future use of tDCS. It is important, therefore, to establish whether tDCS can exert similar effects within non-motor brain areas. The aim of this study was to assess whether anodal tDCS could reduce inhibitory interactions within the human visual cortex. Psychophysical measures of surround suppression were used as an index of inhibition within V1. Overlay suppression, which is thought to originate within the lateral geniculate nucleus (LGN, was also measured as a control. Anodal stimulation of the occipital poles significantly reduced psychophysical surround suppression, but had no effect on overlay suppression. This effect was specific to anodal stimulation as cathodal stimulation had no effect on either measure. These psychophysical results provide the first evidence for tDCS-induced reductions of intracortical inhibition within the human visual cortex.

  15. Task-specific reorganization of the auditory cortex in deaf humans.

    Science.gov (United States)

    Bola, Łukasz; Zimmermann, Maria; Mostowski, Piotr; Jednoróg, Katarzyna; Marchewka, Artur; Rutkowski, Paweł; Szwed, Marcin

    2017-01-24

    The principles that guide large-scale cortical reorganization remain unclear. In the blind, several visual regions preserve their task specificity; ventral visual areas, for example, become engaged in auditory and tactile object-recognition tasks. It remains open whether task-specific reorganization is unique to the visual cortex or, alternatively, whether this kind of plasticity is a general principle applying to other cortical areas. Auditory areas can become recruited for visual and tactile input in the deaf. Although nonhuman data suggest that this reorganization might be task specific, human evidence has been lacking. Here we enrolled 15 deaf and 15 hearing adults into an functional MRI experiment during which they discriminated between temporally complex sequences of stimuli (rhythms). Both deaf and hearing subjects performed the task visually, in the central visual field. In addition, hearing subjects performed the same task in the auditory modality. We found that the visual task robustly activated the auditory cortex in deaf subjects, peaking in the posterior-lateral part of high-level auditory areas. This activation pattern was strikingly similar to the pattern found in hearing subjects performing the auditory version of the task. Although performing the visual task in deaf subjects induced an increase in functional connectivity between the auditory cortex and the dorsal visual cortex, no such effect was found in hearing subjects. We conclude that in deaf humans the high-level auditory cortex switches its input modality from sound to vision but preserves its task-specific activation pattern independent of input modality. Task-specific reorganization thus might be a general principle that guides cortical plasticity in the brain.

  16. Plasticity in the Human Visual Cortex: An Ophthalmology-Based Perspective

    OpenAIRE

    Andreia Martins Rosa; Maria Fátima Silva; Sónia Ferreira; Joaquim Murta; Miguel Castelo-Branco

    2013-01-01

    Neuroplasticity refers to the ability of the brain to reorganize the function and structure of its connections in response to changes in the environment. Adult human visual cortex shows several manifestations of plasticity, such as perceptual learning and adaptation, working under the top-down influence of attention. Plasticity results from the interplay of several mechanisms, including the GABAergic system, epigenetic factors, mitochondrial activity, and structural remodeling of synaptic con...

  17. Differences in female and male development of the human cerebral cortex from birth to age 16

    OpenAIRE

    Hanlon, Harriet Wehner

    1994-01-01

    This study compares the development of the human cerebral cortex of 224 girls and 284 boys in a series of cross-sectional analyses as measured by EEG coherence on normal children's brains (longisectional design). Correlations of these EEG readings taken from all brain regions between a mean age of 6 months and 16 years yield measures of synaptic communication. Time series of these measures reflect the changing growth patterns across the 16 years. Time series of mean EE...

  18. Effects of selective attention on the electrophysiological representation of concurrent sounds in the human auditory cortex.

    Science.gov (United States)

    Bidet-Caulet, Aurélie; Fischer, Catherine; Besle, Julien; Aguera, Pierre-Emmanuel; Giard, Marie-Helene; Bertrand, Olivier

    2007-08-29

    In noisy environments, we use auditory selective attention to actively ignore distracting sounds and select relevant information, as during a cocktail party to follow one particular conversation. The present electrophysiological study aims at deciphering the spatiotemporal organization of the effect of selective attention on the representation of concurrent sounds in the human auditory cortex. Sound onset asynchrony was manipulated to induce the segregation of two concurrent auditory streams. Each stream consisted of amplitude modulated tones at different carrier and modulation frequencies. Electrophysiological recordings were performed in epileptic patients with pharmacologically resistant partial epilepsy, implanted with depth electrodes in the temporal cortex. Patients were presented with the stimuli while they either performed an auditory distracting task or actively selected one of the two concurrent streams. Selective attention was found to affect steady-state responses in the primary auditory cortex, and transient and sustained evoked responses in secondary auditory areas. The results provide new insights on the neural mechanisms of auditory selective attention: stream selection during sound rivalry would be facilitated not only by enhancing the neural representation of relevant sounds, but also by reducing the representation of irrelevant information in the auditory cortex. Finally, they suggest a specialization of the left hemisphere in the attentional selection of fine-grained acoustic information.

  19. Evidence in Support of the Independent Channel Model Describing the Sensorimotor Control of Human Stance Using a Humanoid Robot.

    Science.gov (United States)

    Pasma, Jantsje H; Assländer, Lorenz; van Kordelaar, Joost; de Kam, Digna; Mergner, Thomas; Schouten, Alfred C

    2018-01-01

    The Independent Channel (IC) model is a commonly used linear balance control model in the frequency domain to analyze human balance control using system identification and parameter estimation. The IC model is a rudimentary and noise-free description of balance behavior in the frequency domain, where a stable model representation is not guaranteed. In this study, we conducted firstly time-domain simulations with added noise, and secondly robot experiments by implementing the IC model in a real-world robot (PostuRob II) to test the validity and stability of the model in the time domain and for real world situations. Balance behavior of seven healthy participants was measured during upright stance by applying pseudorandom continuous support surface rotations. System identification and parameter estimation were used to describe the balance behavior with the IC model in the frequency domain. The IC model with the estimated parameters from human experiments was implemented in Simulink for computer simulations including noise in the time domain and robot experiments using the humanoid robot PostuRob II. Again, system identification and parameter estimation were used to describe the simulated balance behavior. Time series, Frequency Response Functions, and estimated parameters from human experiments, computer simulations, and robot experiments were compared with each other. The computer simulations showed similar balance behavior and estimated control parameters compared to the human experiments, in the time and frequency domain. Also, the IC model was able to control the humanoid robot by keeping it upright, but showed small differences compared to the human experiments in the time and frequency domain, especially at high frequencies. We conclude that the IC model, a descriptive model in the frequency domain, can imitate human balance behavior also in the time domain, both in computer simulations with added noise and real world situations with a humanoid robot. This

  20. Evidence in Support of the Independent Channel Model Describing the Sensorimotor Control of Human Stance Using a Humanoid Robot

    Directory of Open Access Journals (Sweden)

    Jantsje H. Pasma

    2018-03-01

    Full Text Available The Independent Channel (IC model is a commonly used linear balance control model in the frequency domain to analyze human balance control using system identification and parameter estimation. The IC model is a rudimentary and noise-free description of balance behavior in the frequency domain, where a stable model representation is not guaranteed. In this study, we conducted firstly time-domain simulations with added noise, and secondly robot experiments by implementing the IC model in a real-world robot (PostuRob II to test the validity and stability of the model in the time domain and for real world situations. Balance behavior of seven healthy participants was measured during upright stance by applying pseudorandom continuous support surface rotations. System identification and parameter estimation were used to describe the balance behavior with the IC model in the frequency domain. The IC model with the estimated parameters from human experiments was implemented in Simulink for computer simulations including noise in the time domain and robot experiments using the humanoid robot PostuRob II. Again, system identification and parameter estimation were used to describe the simulated balance behavior. Time series, Frequency Response Functions, and estimated parameters from human experiments, computer simulations, and robot experiments were compared with each other. The computer simulations showed similar balance behavior and estimated control parameters compared to the human experiments, in the time and frequency domain. Also, the IC model was able to control the humanoid robot by keeping it upright, but showed small differences compared to the human experiments in the time and frequency domain, especially at high frequencies. We conclude that the IC model, a descriptive model in the frequency domain, can imitate human balance behavior also in the time domain, both in computer simulations with added noise and real world situations with a

  1. Attention to Color Sharpens Neural Population Tuning via Feedback Processing in the Human Visual Cortex Hierarchy.

    Science.gov (United States)

    Bartsch, Mandy V; Loewe, Kristian; Merkel, Christian; Heinze, Hans-Jochen; Schoenfeld, Mircea A; Tsotsos, John K; Hopf, Jens-Max

    2017-10-25

    Attention can facilitate the selection of elementary object features such as color, orientation, or motion. This is referred to as feature-based attention and it is commonly attributed to a modulation of the gain and tuning of feature-selective units in visual cortex. Although gain mechanisms are well characterized, little is known about the cortical processes underlying the sharpening of feature selectivity. Here, we show with high-resolution magnetoencephalography in human observers (men and women) that sharpened selectivity for a particular color arises from feedback processing in the human visual cortex hierarchy. To assess color selectivity, we analyze the response to a color probe that varies in color distance from an attended color target. We find that attention causes an initial gain enhancement in anterior ventral extrastriate cortex that is coarsely selective for the target color and transitions within ∼100 ms into a sharper tuned profile in more posterior ventral occipital cortex. We conclude that attention sharpens selectivity over time by attenuating the response at lower levels of the cortical hierarchy to color values neighboring the target in color space. These observations support computational models proposing that attention tunes feature selectivity in visual cortex through backward-propagating attenuation of units less tuned to the target. SIGNIFICANCE STATEMENT Whether searching for your car, a particular item of clothing, or just obeying traffic lights, in everyday life, we must select items based on color. But how does attention allow us to select a specific color? Here, we use high spatiotemporal resolution neuromagnetic recordings to examine how color selectivity emerges in the human brain. We find that color selectivity evolves as a coarse to fine process from higher to lower levels within the visual cortex hierarchy. Our observations support computational models proposing that feature selectivity increases over time by attenuating the

  2. Deconstructing white matter connectivity of human amygdala nuclei with thalamus and cortex subdivisions in vivo.

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    Abivardi, Aslan; Bach, Dominik R

    2017-08-01

    Structural alterations in long-range amygdala connections are proposed to crucially underlie several neuropsychiatric disorders. While progress has been made in elucidating the function of these connections, our understanding of their structure in humans remains sparse and non-systematic. Harnessing diffusion-weighted imaging and probabilistic tractography in humans, we investigate connections between two main amygdala nucleus groups, thalamic nuclei, and cortex. We first parcellated amygdala into deep (basolateral) and superficial (centrocortical) nucleus groups, and thalamus into six subregions, using previously established protocols based on connectivity. Cortex was parcellated based on T1-weighted images. We found substantial amygdala connections to thalamus, with different patterns for the two amygdala nuclei. Crucially, we describe direct subcortical connections between amygdala and paraventricular thalamus. Different from rodents but similar to non-human primates, these are more pronounced for basolateral than centrocortical amygdala. Substantial white-matter connectivity between amygdala and visual pulvinar is also more pronounced for basolateral amygdala. Furthermore, we establish detailed connectivity profiles for basolateral and centrocortical amygdala to cortical regions. These exhibit cascadic connections with sensory cortices as suggested previously based on tracer methods in non-human animals. We propose that the quantitative connectivity profiles provided here may guide future work on normal and pathological function of human amygdala. Hum Brain Mapp 38:3927-3940, 2017. © 2017 Wiley Periodicals, Inc. © 2017 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

  3. The motor cortex drives the muscles during walking in human subjects

    DEFF Research Database (Denmark)

    Petersen, Tue Hvass; Willerslev-Olsen, Maria; Conway, B A

    2012-01-01

    Indirect evidence that the motor cortex and the corticospinal tract contribute to the control of walking in human subjects has been provided in previous studies. In the present study we used coherence analysis of the coupling between EEG and EMG from active leg muscles during human walking...... area and EMG from the anterior tibial muscle was found in the frequency band 24–40 Hz prior to heel strike during the swing phase of walking. This signifies that rhythmic cortical activity in the 24–40 Hz frequency band is transmitted via the corticospinal tract to the active muscles during walking...

  4. Neuromodulatory neurotransmitters influence LTP-like plasticity in human cortex: a pharmaco-TMS study.

    Science.gov (United States)

    Korchounov, Alexei; Ziemann, Ulf

    2011-08-01

    Long-term potentiation (LTP) of synaptic efficacy is considered a fundamental mechanism of learning and memory. At the cellular level a large body of evidence demonstrated that the major neuromodulatory neurotransmitters dopamine (DA), norepinephrine (NE), and acetylcholine (ACh) influence LTP magnitude. Noninvasive brain stimulation protocols provide the opportunity to study LTP-like plasticity at the systems level of human cortex. Here we applied paired associative stimulation (PAS) to induce LTP-like plasticity in the primary motor cortex of eight healthy subjects. In a double-blind, randomized, placebo-controlled, crossover design, the acute effects of a single oral dose of the neuromodulatory drugs cabergoline (DA agonist), haloperidol (DA antagonist), methylphenidate (indirect NE agonist), prazosine (NE antagonist), tacrine (ACh agonist), and biperiden (ACh antagonist) on PAS-induced LTP-like plasticity were examined. The antagonists haloperidol, prazosine, and biperiden depressed significantly the PAS-induced LTP-like plasticity observed under placebo, whereas the agonists cabergoline, methylphenidate, and tacrine had no effect. Findings demonstrate that antagonists in major neuromodulatory neurotransmitter systems suppress LTP-like plasticity at the systems level of human cortex, in accord with evidence of their modulating action of LTP at the cellular level. This provides further supportive evidence for the known detrimental effects of these drugs on LTP-dependent mechanisms such as learning and memory.

  5. Attentional load modulates responses of human primary visual cortex to invisible stimuli.

    Science.gov (United States)

    Bahrami, Bahador; Lavie, Nilli; Rees, Geraint

    2007-03-20

    Visual neuroscience has long sought to determine the extent to which stimulus-evoked activity in visual cortex depends on attention and awareness. Some influential theories of consciousness maintain that the allocation of attention is restricted to conscious representations [1, 2]. However, in the load theory of attention [3], competition between task-relevant and task-irrelevant stimuli for limited-capacity attention does not depend on conscious perception of the irrelevant stimuli. The critical test is whether the level of attentional load in a relevant task would determine unconscious neural processing of invisible stimuli. Human participants were scanned with high-field fMRI while they performed a foveal task of low or high attentional load. Irrelevant, invisible monocular stimuli were simultaneously presented peripherally and were continuously suppressed by a flashing mask in the other eye [4]. Attentional load in the foveal task strongly modulated retinotopic activity evoked in primary visual cortex (V1) by the invisible stimuli. Contrary to traditional views [1, 2, 5, 6], we found that availability of attentional capacity determines neural representations related to unconscious processing of continuously suppressed stimuli in human primary visual cortex. Spillover of attention to cortical representations of invisible stimuli (under low load) cannot be a sufficient condition for their awareness.

  6. Development and function of human cerebral cortex neural networks from pluripotent stem cells in vitro.

    Science.gov (United States)

    Kirwan, Peter; Turner-Bridger, Benita; Peter, Manuel; Momoh, Ayiba; Arambepola, Devika; Robinson, Hugh P C; Livesey, Frederick J

    2015-09-15

    A key aspect of nervous system development, including that of the cerebral cortex, is the formation of higher-order neural networks. Developing neural networks undergo several phases with distinct activity patterns in vivo, which are thought to prune and fine-tune network connectivity. We report here that human pluripotent stem cell (hPSC)-derived cerebral cortex neurons form large-scale networks that reflect those found in the developing cerebral cortex in vivo. Synchronised oscillatory networks develop in a highly stereotyped pattern over several weeks in culture. An initial phase of increasing frequency of oscillations is followed by a phase of decreasing frequency, before giving rise to non-synchronous, ordered activity patterns. hPSC-derived cortical neural networks are excitatory, driven by activation of AMPA- and NMDA-type glutamate receptors, and can undergo NMDA-receptor-mediated plasticity. Investigating single neuron connectivity within PSC-derived cultures, using rabies-based trans-synaptic tracing, we found two broad classes of neuronal connectivity: most neurons have small numbers (40). These data demonstrate that the formation of hPSC-derived cortical networks mimics in vivo cortical network development and function, demonstrating the utility of in vitro systems for mechanistic studies of human forebrain neural network biology. © 2015. Published by The Company of Biologists Ltd.

  7. Functional connection between posterior superior temporal gyrus and ventrolateral prefrontal cortex in human.

    Science.gov (United States)

    Garell, P C; Bakken, H; Greenlee, J D W; Volkov, I; Reale, R A; Oya, H; Kawasaki, H; Howard, M A; Brugge, J F

    2013-10-01

    The connection between auditory fields of the temporal lobe and prefrontal cortex has been well characterized in nonhuman primates. Little is known of temporofrontal connectivity in humans, however, due largely to the fact that invasive experimental approaches used so successfully to trace anatomical pathways in laboratory animals cannot be used in humans. Instead, we used a functional tract-tracing method in 12 neurosurgical patients with multicontact electrode arrays chronically implanted over the left (n = 7) or right (n = 5) perisylvian temporal auditory cortex (area PLST) and the ventrolateral prefrontal cortex (VLPFC) of the inferior frontal gyrus (IFG) for diagnosis and treatment of medically intractable epilepsy. Area PLST was identified by the distribution of average auditory-evoked potentials obtained in response to simple and complex sounds. The same sounds evoked little if there is any activity in VLPFC. A single bipolar electrical pulse (0.2 ms, charge-balanced) applied between contacts within physiologically identified PLST resulted in polyphasic evoked potentials clustered in VLPFC, with greatest activation being in pars triangularis of the IFG. The average peak latency of the earliest negative deflection of the evoked potential on VLPFC was 13.48 ms (range: 9.0-18.5 ms), providing evidence for a rapidly conducting pathway between area PLST and VLPFC.

  8. Distinct Oscillatory Frequencies Underlie Excitability of Human Occipital and Parietal Cortex.

    Science.gov (United States)

    Samaha, Jason; Gosseries, Olivia; Postle, Bradley R

    2017-03-15

    Transcranial magnetic stimulation (TMS) of human occipital and posterior parietal cortex can give rise to visual sensations called phosphenes. We used near-threshold TMS with concurrent EEG recordings to measure how oscillatory brain dynamics covary, on single trials, with the perception of phosphenes after occipital and parietal TMS. Prestimulus power and phase, predominantly in the alpha band (8-13 Hz), predicted occipital TMS phosphenes, whereas higher-frequency beta-band (13-20 Hz) power (but not phase) predicted parietal TMS phosphenes. TMS-evoked responses related to phosphene perception were similar across stimulation sites and were characterized by an early (200 ms) posterior negativity and a later (>300 ms) parietal positivity in the time domain and an increase in low-frequency (∼5-7 Hz) power followed by a broadband decrease in alpha/beta power in the time-frequency domain. These correlates of phosphene perception closely resemble known electrophysiological correlates of conscious perception of near-threshold visual stimuli. The regionally differential pattern of prestimulus predictors of phosphene perception suggests that distinct frequencies may reflect cortical excitability in occipital versus posterior parietal cortex, calling into question the broader assumption that the alpha rhythm may serve as a general index of cortical excitability. SIGNIFICANCE STATEMENT Alpha-band oscillations are thought to reflect cortical excitability and are therefore ascribed an important role in gating information transmission across cortex. We probed cortical excitability directly in human occipital and parietal cortex and observed that, whereas alpha-band dynamics indeed reflect excitability of occipital areas, beta-band activity was most predictive of parietal cortex excitability. Differences in the state of cortical excitability predicted perceptual outcomes (phosphenes), which were manifest in both early and late patterns of evoked activity, revealing the time

  9. The basis of orientation decoding in human primary visual cortex: fine- or coarse-scale biases?

    Science.gov (United States)

    Maloney, Ryan T

    2015-01-01

    Orientation signals in human primary visual cortex (V1) can be reliably decoded from the multivariate pattern of activity as measured with functional magnetic resonance imaging (fMRI). The precise underlying source of these decoded signals (whether by orientation biases at a fine or coarse scale in cortex) remains a matter of some controversy, however. Freeman and colleagues (J Neurosci 33: 19695-19703, 2013) recently showed that the accuracy of decoding of spiral patterns in V1 can be predicted by a voxel's preferred spatial position (the population receptive field) and its coarse orientation preference, suggesting that coarse-scale biases are sufficient for orientation decoding. Whether they are also necessary for decoding remains an open question, and one with implications for the broader interpretation of multivariate decoding results in fMRI studies. Copyright © 2015 the American Physiological Society.

  10. Neural representations of social status hierarchy in human inferior parietal cortex.

    Science.gov (United States)

    Chiao, Joan Y; Harada, Tokiko; Oby, Emily R; Li, Zhang; Parrish, Todd; Bridge, Donna J

    2009-01-01

    Mental representations of social status hierarchy share properties with that of numbers. Previous neuroimaging studies have shown that the neural representation of numerical magnitude lies within a network of regions within inferior parietal cortex. However the neural basis of social status hierarchy remains unknown. Using fMRI, we studied subjects while they compared social status magnitude of people, objects and symbols, as well as numerical magnitude. Both social status and number comparisons recruited bilateral intraparietal sulci. We also observed a semantic distance effect whereby neural activity within bilateral intraparietal sulci increased for semantically close relative to far numerical and social status comparisons. These results demonstrate that social status and number comparisons recruit distinct and overlapping neuronal representations within human inferior parietal cortex.

  11. Integration of Visual and Proprioceptive Limb Position Information in Human Posterior Parietal, Premotor, and Extrastriate Cortex.

    Science.gov (United States)

    Limanowski, Jakub; Blankenburg, Felix

    2016-03-02

    The brain constructs a flexible representation of the body from multisensory information. Previous work on monkeys suggests that the posterior parietal cortex (PPC) and ventral premotor cortex (PMv) represent the position of the upper limbs based on visual and proprioceptive information. Human experiments on the rubber hand illusion implicate similar regions, but since such experiments rely on additional visuo-tactile interactions, they cannot isolate visuo-proprioceptive integration. Here, we independently manipulated the position (palm or back facing) of passive human participants' unseen arm and of a photorealistic virtual 3D arm. Functional magnetic resonance imaging (fMRI) revealed that matching visual and proprioceptive information about arm position engaged the PPC, PMv, and the body-selective extrastriate body area (EBA); activity in the PMv moreover reflected interindividual differences in congruent arm ownership. Further, the PPC, PMv, and EBA increased their coupling with the primary visual cortex during congruent visuo-proprioceptive position information. These results suggest that human PPC, PMv, and EBA evaluate visual and proprioceptive position information and, under sufficient cross-modal congruence, integrate it into a multisensory representation of the upper limb in space. The position of our limbs in space constantly changes, yet the brain manages to represent limb position accurately by combining information from vision and proprioception. Electrophysiological recordings in monkeys have revealed neurons in the posterior parietal and premotor cortices that seem to implement and update such a multisensory limb representation, but this has been difficult to demonstrate in humans. Our fMRI experiment shows that human posterior parietal, premotor, and body-selective visual brain areas respond preferentially to a virtual arm seen in a position corresponding to one's unseen hidden arm, while increasing their communication with regions conveying visual

  12. Genes expressed in specific areas of the human fetal cerebral cortex display distinct patterns of evolution.

    Directory of Open Access Journals (Sweden)

    Nelle Lambert

    2011-03-01

    Full Text Available The developmental mechanisms through which the cerebral cortex increased in size and complexity during primate evolution are essentially unknown. To uncover genetic networks active in the developing cerebral cortex, we combined three-dimensional reconstruction of human fetal brains at midgestation and whole genome expression profiling. This novel approach enabled transcriptional characterization of neurons from accurately defined cortical regions containing presumptive Broca and Wernicke language areas, as well as surrounding associative areas. We identified hundreds of genes displaying differential expression between the two regions, but no significant difference in gene expression between left and right hemispheres. Validation by qRTPCR and in situ hybridization confirmed the robustness of our approach and revealed novel patterns of area- and layer-specific expression throughout the developing cortex. Genes differentially expressed between cortical areas were significantly associated with fast-evolving non-coding sequences harboring human-specific substitutions that could lead to divergence in their repertoires of transcription factor binding sites. Strikingly, while some of these sequences were accelerated in the human lineage only, many others were accelerated in chimpanzee and/or mouse lineages, indicating that genes important for cortical development may be particularly prone to changes in transcriptional regulation across mammals. Genes differentially expressed between cortical regions were also enriched for transcriptional targets of FoxP2, a key gene for the acquisition of language abilities in humans. Our findings point to a subset of genes with a unique combination of cortical areal expression and evolutionary patterns, suggesting that they play important roles in the transcriptional network underlying human-specific neural traits.

  13. Low Doses of Ethanol Enhance LTD-like Plasticity in Human Motor Cortex.

    Science.gov (United States)

    Fuhl, Anna; Müller-Dahlhaus, Florian; Lücke, Caroline; Toennes, Stefan W; Ziemann, Ulf

    2015-12-01

    Humans liberally use ethanol for its facilitating effects on social interactions but its effects on central nervous system function remain underexplored. We have recently described that very low doses of ethanol abolish long-term potentiation (LTP)-like plasticity in human cortex, most likely through enhancement of tonic inhibition [Lücke et al, 2014, Neuropsychopharmacology 39:1508-18]. Here, we studied the effects of low-dose ethanol on long-term depression (LTD)-like plasticity. LTD-like plasticity was induced in human motor cortex by paired associative transcranial magnetic stimulation (PASLTD), and measured as decreases of motor evoked potential input-output curve (IO-curve). In addition, sedation was measured by decreases in saccade peak velocity (SPV). Ethanol in two low doses (EtOH<10mM, EtOH<20mM) was compared to single oral doses of alprazolam (APZ, 1mg) a classical benzodiazepine, and zolpidem (ZLP, 10 mg), a non-benzodiazepine hypnotic, in a double-blinded randomized placebo-controlled crossover design in ten healthy human subjects. EtOH<10mM and EtOH<20mM but not APZ or ZLP enhanced the PASLTD-induced LTD-like plasticity, while APZ and ZLP but not EtOH<10mM or EtOH<20mM decreased SPV. Non-sedating low doses of ethanol, easily reached during social drinking, enhance LTD-like plasticity in human cortex. This effect is most likely explained by the activation of extrasynaptic α4-subunit containing gamma-aminobutyric type A receptors by low-dose EtOH, resulting in increased tonic inhibition. Findings may stimulate cellular research on the role of tonic inhibition in regulating excitability and plasticity of cortical neuronal networks.

  14. Inverse biomimetics: how robots can help to verify concepts concerning sensorimotor control of human arm and leg movements.

    Science.gov (United States)

    Kalveram, Karl Theodor; Seyfarth, André

    2009-01-01

    Simulation test, hardware test and behavioral comparison test are proposed to experimentally verify whether a technical control concept for limb movements is logically precise, physically sound, and biologically relevant. Thereby, robot test-beds may play an integral part by mimicking functional limb movements. The procedure is exemplarily demonstrated for human aiming movements with the forearm: when comparing competitive control concepts, these movements are described best by a spring-like operating muscular-skeletal device which is assisted by feedforward control through an inverse internal model of the limb--without regress to a forward model of the limb. In a perspective on hopping, the concept of exploitive control is addressed, and its comparison to concepts derived from classical control theory advised.

  15. Dynamic expression of calretinin in embryonic and early fetal human cortex

    Directory of Open Access Journals (Sweden)

    Miriam eGonzalez-Gomez

    2014-06-01

    Full Text Available Calretinin (CR is one of the earliest neurochemical markers in human corticogenesis. In embryos from Carnegie stages (CS 17 to 23, calbindin (CB and CR stain opposite poles of the incipient cortex suggesting early regionalization: CB marks the neuroepithelium of the medial boundary of the cortex with the choroid plexus (cortical hem. By contrast, CR is confined to the subventricular zone (SVZ of the lateral and caudal ganglionic eminences at the pallial-subpallial boundary (PSB, or antihem, from where CR+/Tbr1- neurons migrate toward piriform cortex and amygdala as a component of the lateral cortical stream. At CS 19, columns of CR+ cells arise in the rostral cortex, and contribute at CS 20 to the monolayer of horizontal Tbr1+/CR+ and GAD+ cells in the preplate. At CS 21, the pioneer cortical plate appears as a radial aggregation of CR+/Tbr1+ neurons, which cover the entire future neocortex and extend the first corticofugal axons. CR expression in early human corticogenesis is thus not restricted to interneurons, but is also present in the first excitatory projection neurons of the cortex. At CS 21/22, the cortical plate is established following a lateral to medial gradient, when Tbr1+/CR- neurons settle within the pioneer cortical plate, and thus separate superficial and deep pioneer neurons. CR+ pioneer neurons disappear shortly after the formation of the cortical plate. Reelin+ Cajal-Retzius cells begin to express CR around CS21 (7/8 PCW. At CS 21-23, the CR+ SVZ at the PSB is the source of CR+ interneurons migrating into the cortical SVZ. In turn, CB+ interneurons migrate from the subpallium into the intermediate zone following the fibers of the internal capsule. Early CR+ and CB+ interneurons thus have different origins and migratory routes. CR+ cell populations in the embryonic telencephalon take part in a complex sequence of events not analyzed so far in other mammalian species, which may represent a distinctive trait of the initial steps

  16. Dopamine release in human striatum induced by repetitive transcranial magnetic stimulation over dorsolateral prefrontal cortex

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Sang Soo; Yoon, Eun Jin; Kim, Yu Kyeong; Lee, Won Woo; Kim, Sang Eun [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2005-07-01

    Animal study suggests that prefrontal cortex plays an important Animal studies suggest that prefrontal cortex plays an important role in the modulation of dopamine (DA) release in subcortical areas. However, little is known about the relationship between DA release and prefrontal activation in human. We investigated whether repetitive transcranial magnetic stimulation (rTMS) over left dorsolateral prefrontal cortex (DLPFC) influences DA release in human striatum with SPECT measurements of striatal binding of [123I)iodobenzamide (IBZM), a DA D2 receptor radioligand that is sensitive to endogenous DA. Five healthy male volunteers (age, 25{+-}2 yr) were studied with brain [123I]IBZM SPECT under three conditions (resting, Sham stimulation, and active rTMS over left DLPFC), while receiving a bolus plus constant infusion of [123I]IBZM DLPFC was defined as a 6 cm anterior and 1cm lateral from the primary motor cortex. rTMS session consisted of three blocks, in each block, 15 trains of 2 see duration were delivered with 10 Hz stimulation frequency, 100% motor threshold, and between-train intervals of 10 sec. Striatal V3', calculated as (striatal - occipital) / occipital activity ratio, was measured under equilibrium condition, at baseline and after sham and active rTMS. Sham stimulation did not affect striatal V3'. rTMS over DLPFC induced reduction of V3' in the ipsilateral and contralateral striatum by 9.7% {+-} 1.3% and 10.6% {+-} 3.2%, respectively, compared with sham procedures (P < 0.01 and P < 0.01, respectively), indicating striatal DA release elicited by rTMS over DLPFC. V3' reduction in the ipsilateral caudate nucleus was greater than that in the contralateral caudate nucleus (9.9% {+-} 4.5% vs. 6.6% {+-} 3.1%, P < 0.05). These data demonstrate DA release in human striatum induced by rTMS over DLPFC, supporting that cortico-striatal fibers originating in prefrontal cortex are involved in local DA release.

  17. Dopamine release in human striatum induced by repetitive transcranial magnetic stimulation over dorsolateral prefrontal cortex

    International Nuclear Information System (INIS)

    Cho, Sang Soo; Yoon, Eun Jin; Kim, Yu Kyeong; Lee, Won Woo; Kim, Sang Eun

    2005-01-01

    Animal study suggests that prefrontal cortex plays an important Animal studies suggest that prefrontal cortex plays an important role in the modulation of dopamine (DA) release in subcortical areas. However, little is known about the relationship between DA release and prefrontal activation in human. We investigated whether repetitive transcranial magnetic stimulation (rTMS) over left dorsolateral prefrontal cortex (DLPFC) influences DA release in human striatum with SPECT measurements of striatal binding of [123I)iodobenzamide (IBZM), a DA D2 receptor radioligand that is sensitive to endogenous DA. Five healthy male volunteers (age, 25±2 yr) were studied with brain [123I]IBZM SPECT under three conditions (resting, Sham stimulation, and active rTMS over left DLPFC), while receiving a bolus plus constant infusion of [123I]IBZM DLPFC was defined as a 6 cm anterior and 1cm lateral from the primary motor cortex. rTMS session consisted of three blocks, in each block, 15 trains of 2 see duration were delivered with 10 Hz stimulation frequency, 100% motor threshold, and between-train intervals of 10 sec. Striatal V3', calculated as (striatal - occipital) / occipital activity ratio, was measured under equilibrium condition, at baseline and after sham and active rTMS. Sham stimulation did not affect striatal V3'. rTMS over DLPFC induced reduction of V3' in the ipsilateral and contralateral striatum by 9.7% ± 1.3% and 10.6% ± 3.2%, respectively, compared with sham procedures (P < 0.01 and P < 0.01, respectively), indicating striatal DA release elicited by rTMS over DLPFC. V3' reduction in the ipsilateral caudate nucleus was greater than that in the contralateral caudate nucleus (9.9% ± 4.5% vs. 6.6% ± 3.1%, P < 0.05). These data demonstrate DA release in human striatum induced by rTMS over DLPFC, supporting that cortico-striatal fibers originating in prefrontal cortex are involved in local DA release

  18. Plasticity resembling spike-timing dependent synaptic plasticity: the evidence in human cortex

    Directory of Open Access Journals (Sweden)

    Florian Müller-Dahlhaus

    2010-07-01

    Full Text Available Spike-timing dependent plasticity (STDP has been studied extensively in a variety of animal models during the past decade but whether it can be studied at the systems level of the human cortex has been a matter of debate. Only recently newly developed non-invasive brain stimulation techniques such as transcranial magnetic stimulation (TMS have made it possible to induce and assess timing dependent plasticity in conscious human subjects. This review will present a critical synopsis of these experiments, which suggest that several of the principal characteristics and molecular mechanisms of TMS-induced plasticity correspond to those of STDP as studied at a cellular level. TMS combined with a second phasic stimulation modality can induce bidirectional long-lasting changes in the excitability of the stimulated cortex, whose polarity depends on the order of the associated stimulus-evoked events within a critical time window of tens of milliseconds. Pharmacological evidence suggests an NMDA receptor mediated form of synaptic plasticity. Studies in human motor cortex demonstrated that motor learning significantly modulates TMS-induced timing dependent plasticity, and, conversely, may be modulated bidirectionally by prior TMS-induced plasticity, providing circumstantial evidence that long-term potentiation-like mechanisms may be involved in motor learning. In summary, convergent evidence is being accumulated for the contention that it is now possible to induce STDP-like changes in the intact human central nervous system by means of TMS to study and interfere with synaptic plasticity in neural circuits in the context of behaviour such as learning and memory.

  19. Parcellation of the human orbitofrontal cortex based on gray matter volume covariance.

    Science.gov (United States)

    Liu, Huaigui; Qin, Wen; Qi, Haotian; Jiang, Tianzi; Yu, Chunshui

    2015-02-01

    The human orbitofrontal cortex (OFC) is an enigmatic brain region that cannot be parcellated reliably using diffusional and functional magnetic resonance imaging (fMRI) because there is signal dropout that results from an inherent defect in imaging techniques. We hypothesise that the OFC can be reliably parcellated into subregions based on gray matter volume (GMV) covariance patterns that are derived from artefact-free structural images. A total of 321 healthy young subjects were examined by high-resolution structural MRI. The OFC was parcellated into subregions-based GMV covariance patterns; and then sex and laterality differences in GMV covariance pattern of each OFC subregion were compared. The human OFC was parcellated into the anterior (OFCa), medial (OFCm), posterior (OFCp), intermediate (OFCi), and lateral (OFCl) subregions. This parcellation scheme was validated by the same analyses of the left OFC and the bilateral OFCs in male and female subjects. Both visual observation and quantitative comparisons indicated a unique GMV covariance pattern for each OFC subregion. These OFC subregions mainly covaried with the prefrontal and temporal cortices, cingulate cortex and amygdala. In addition, GMV correlations of most OFC subregions were similar across sex and laterality except for significant laterality difference in the OFCl. The right OFCl had stronger GMV correlation with the right inferior frontal cortex. Using high-resolution structural images, we established a reliable parcellation scheme for the human OFC, which may provide an in vivo guide for subregion-level studies of this region and improve our understanding of the human OFC at subregional levels. © 2014 Wiley Periodicals, Inc.

  20. Cortical oscillations in auditory perception and speech: evidence for two temporal windows in human auditory cortex

    Directory of Open Access Journals (Sweden)

    Huan eLuo

    2012-05-01

    Full Text Available Natural sounds, including vocal communication sounds, contain critical information at multiple time scales. Two essential temporal modulation rates in speech have been argued to be in the low gamma band (~20-80 ms duration information and the theta band (~150-300 ms, corresponding to segmental and syllabic modulation rates, respectively. On one hypothesis, auditory cortex implements temporal integration using time constants closely related to these values. The neural correlates of a proposed dual temporal window mechanism in human auditory cortex remain poorly understood. We recorded MEG responses from participants listening to non-speech auditory stimuli with different temporal structures, created by concatenating frequency-modulated segments of varied segment durations. We show that these non-speech stimuli with temporal structure matching speech-relevant scales (~25 ms and ~200 ms elicit reliable phase tracking in the corresponding associated oscillatory frequencies (low gamma and theta bands. In contrast, stimuli with non-matching temporal structure do not. Furthermore, the topography of theta band phase tracking shows rightward lateralization while gamma band phase tracking occurs bilaterally. The results support the hypothesis that there exists multi-time resolution processing in cortex on discontinuous scales and provide evidence for an asymmetric organization of temporal analysis (asymmetrical sampling in time, AST. The data argue for a macroscopic-level neural mechanism underlying multi-time resolution processing: the sliding and resetting of intrinsic temporal windows on privileged time scales.

  1. Dissociable contributions of the human amygdala and orbitofrontal cortex to incentive motivation and goal selection.

    Science.gov (United States)

    Arana, F Sergio; Parkinson, John A; Hinton, Elanor; Holland, Anthony J; Owen, Adrian M; Roberts, Angela C

    2003-10-22

    Theories of incentive motivation attempt to capture the way in which objects and events in the world can acquire high motivational value and drive behavior, even in the absence of a clear biological need. In addition, for an individual to select the most appropriate goal, the incentive values of competing desirable objects need to be defined and compared. The present study examined the neural substrates by which appetitive incentive value influences prospective goal selection, using positron emission tomographic neuroimaging in humans. Sated subjects were shown a series of restaurant menus that varied in incentive value, specifically tailored for each individual, and in half the trials, were asked to make a selection from the menu. The amygdala was activated by high-incentive menus regardless of whether a choice was required. Indeed, activity in this region varied as a function of individual subjective ratings of incentive value. In contrast, distinct regions of the orbitofrontal cortex were recruited both during incentive judgments and goal selection. Activity in the medial orbital cortex showed a greater response to high-incentive menus and when making a choice, with the latter activity also correlating with subjective ratings of difficulty. Lateral orbitofrontal activity was observed selectively when participants had to suppress responses to alternative desirable items to select their most preferred. Taken together, these data highlight the differential contribution of the amygdala and regions within the orbitofrontal cortex in a neural system underlying the selection of goals based on the prospective incentive value of stimuli, over and above homeostatic influences.

  2. Robust selectivity to two-object images in human visual cortex

    Science.gov (United States)

    Agam, Yigal; Liu, Hesheng; Papanastassiou, Alexander; Buia, Calin; Golby, Alexandra J.; Madsen, Joseph R.; Kreiman, Gabriel

    2010-01-01

    SUMMARY We can recognize objects in a fraction of a second in spite of the presence of other objects [1–3]. The responses in macaque areas V4 and inferior temporal cortex [4–15] to a neuron’s preferred stimuli are typically suppressed by the addition of a second object within the receptive field (see however [16, 17]). How can this suppression be reconciled with rapid visual recognition in complex scenes? One option is that certain “special categories” are unaffected by other objects [18] but this leaves the problem unsolved for other categories. Another possibility is that serial attentional shifts help ameliorate the problem of distractor objects [19–21]. Yet, psychophysical studies [1–3], scalp recordings [1] and neurophysiological recordings [14, 16, 22–24], suggest that the initial sweep of visual processing contains a significant amount of information. We recorded intracranial field potentials in human visual cortex during presentation of flashes of two-object images. Visual selectivity from temporal cortex during the initial ~200 ms was largely robust to the presence of other objects. We could train linear decoders on the responses to isolated objects and decode information in two-object images. These observations are compatible with parallel, hierarchical and feed-forward theories of rapid visual recognition [25] and may provide a neural substrate to begin to unravel rapid recognition in natural scenes. PMID:20417105

  3. Encoding of Touch Intensity But Not Pleasantness in Human Primary Somatosensory Cortex

    Science.gov (United States)

    Laubacher, Claire M.; Olausson, Håkan; Wang, Binquan; Spagnolo, Primavera A.; Bushnell, M. Catherine

    2016-01-01

    Growing interest in affective touch has delineated a neural network that bypasses primary somatosensory cortex (S1). Several recent studies, however, have cast doubt on the segregation of touch discrimination and affect, suggesting that S1 also encodes affective qualities. We used functional magnetic resonance imaging (fMRI) and repetitive transcranial magnetic stimulation (rTMS) to examine the role of S1 in processing touch intensity and pleasantness. Twenty-six healthy human adults rated brushing on the hand during fMRI. Intensity ratings significantly predicted activation in S1, whereas pleasantness ratings predicted activation only in the anterior cingulate cortex. Nineteen subjects also received inhibitory rTMS over right hemisphere S1 and the vertex (control). After S1 rTMS, but not after vertex rTMS, sensory discrimination was reduced and subjects with reduced sensory discrimination rated touch as more intense. In contrast, rTMS did not alter ratings of touch pleasantness. Our findings support divergent neural processing of touch intensity and pleasantness, with affective touch encoded outside of S1. SIGNIFICANCE STATEMENT Growing interest in affective touch has identified a neural network that bypasses primary somatosensory cortex (S1). Several recent studies, however, cast doubt on the separation of touch discrimination and affect. We used functional magnetic resonance imaging and repetitive transcranial magnetic stimulation to demonstrate the representation of touch discrimination and intensity in S1, but the representation of pleasantness in the anterior cingulate cortex, not S1. Our findings support divergent neural processing of touch intensity and pleasantness, with affective touch encoded outside of S1. Our study contributes to growing delineation of the affective touch system, a crucial step in understanding its dysregulation in numerous clinical conditions such as autism, eating disorders, depression, and chronic pain. PMID:27225773

  4. Cortical thickness development of human primary visual cortex related to the age of blindness onset.

    Science.gov (United States)

    Li, Qiaojun; Song, Ming; Xu, Jiayuan; Qin, Wen; Yu, Chunshui; Jiang, Tianzi

    2017-08-01

    Blindness primarily induces structural alteration in the primary visual cortex (V1). Some studies have found that the early blind subjects had a thicker V1 compared to sighted controls, whereas late blind subjects showed no significant differences in the V1. This implies that the age of blindness onset may exert significant effects on the development of cortical thickness of the V1. However, no previous research used a trajectory of the age of blindness onset-related changes to investigate these effects. Here we explored this issue by mapping the cortical thickness trajectory of the V1 against the age of blindness onset using data from 99 blind individuals whose age of blindness onset ranged from birth to 34 years. We found that the cortical thickness of the V1 could be fitted well with a quadratic curve in both the left (F = 11.59, P = 3 × 10 -5 ) and right hemispheres (F = 6.54, P = 2 × 10 -3 ). Specifically, the cortical thickness of the V1 thinned rapidly during childhood and adolescence and did not change significantly thereafter. This trend was not observed in the primary auditory cortex (A1), primary motor cortex (M1), or primary somatosensory cortex (S1). These results provide evidence that an onset of blindness before adulthood significantly affects the cortical thickness of the V1 and suggest a critical period for cortical development of the human V1.

  5. Top-down modulation of human early visual cortex after stimulus offset supports successful postcued report.

    Science.gov (United States)

    Sergent, Claire; Ruff, Christian C; Barbot, Antoine; Driver, Jon; Rees, Geraint

    2011-08-01

    Modulations of sensory processing in early visual areas are thought to play an important role in conscious perception. To date, most empirical studies focused on effects occurring before or during visual presentation. By contrast, several emerging theories postulate that sensory processing and conscious visual perception may also crucially depend on late top-down influences, potentially arising after a visual display. To provide a direct test of this, we performed an fMRI study using a postcued report procedure. The ability to report a target at a specific spatial location in a visual display can be enhanced behaviorally by symbolic auditory postcues presented shortly after that display. Here we showed that such auditory postcues can enhance target-specific signals in early human visual cortex (V1 and V2). For postcues presented 200 msec after stimulus termination, this target-specific enhancement in visual cortex was specifically associated with correct conscious report. The strength of this modulation predicted individual levels of performance in behavior. By contrast, although later postcues presented 1000 msec after stimulus termination had some impact on activity in early visual cortex, this modulation no longer related to conscious report. These results demonstrate that within a critical time window of a few hundred milliseconds after a visual stimulus has disappeared, successful conscious report of that stimulus still relates to the strength of top-down modulation in early visual cortex. We suggest that, within this critical time window, sensory representation of a visual stimulus is still under construction and so can still be flexibly influenced by top-down modulatory processes.

  6. Binaural fusion and the representation of virtual pitch in the human auditory cortex.

    Science.gov (United States)

    Pantev, C; Elbert, T; Ross, B; Eulitz, C; Terhardt, E

    1996-10-01

    The auditory system derives the pitch of complex tones from the tone's harmonics. Research in psychoacoustics predicted that binaural fusion was an important feature of pitch processing. Based on neuromagnetic human data, the first neurophysiological confirmation of binaural fusion in hearing is presented. The centre of activation within the cortical tonotopic map corresponds to the location of the perceived pitch and not to the locations that are activated when the single frequency constituents are presented. This is also true when the different harmonics of a complex tone are presented dichotically. We conclude that the pitch processor includes binaural fusion to determine the particular pitch location which is activated in the auditory cortex.

  7. Level of action of cathodal DC polarisation induced inhibition of the human motor cortex.

    Science.gov (United States)

    Nitsche, Michael A; Nitsche, Maren S; Klein, Cornelia C; Tergau, Frithjof; Rothwell, John C; Paulus, Walter

    2003-04-01

    To induce prolonged motor cortical excitability reductions by transcranial direct current stimulation in the human. Cathodal direct current stimulation was applied transcranially to the hand area of the human primary motor cortex from 5 to 9 min in separate sessions in twelve healthy subjects. Cortico-spinal excitability was tested by single pulse transcranial magnetic stimulation. Transcranial electrical stimulation and H-reflexes were used to learn about the origin of the excitability changes. Neurone specific enolase was measured before and after the stimulation to prove the safety of the stimulation protocol. Five and 7 min direct current stimulation resulted in motor cortical excitability reductions, which lasted for minutes after the end of stimulation, 9 min stimulation induced after-effects for up to an hour after the end of stimulation, as revealed by transcranial magnetic stimulation. Muscle evoked potentials elicited by transcranial electric stimulation and H-reflexes did not change. Neurone specific enolase concentrations remained stable throughout the experiments. Cathodal transcranial direct current stimulation is capable of inducing prolonged excitability reductions in the human motor cortex non-invasively. These changes are most probably localised intracortically.

  8. A functional magnetic resonance imaging investigation of visual hallucinations in the human striate cortex.

    Science.gov (United States)

    Abid, Hina; Ahmad, Fayyaz; Lee, Soo Y; Park, Hyun W; Im, Dongmi; Ahmad, Iftikhar; Chaudhary, Safee U

    2016-11-29

    Human beings frequently experience fear, phobia, migraine and hallucinations, however, the cerebral mechanisms underpinning these conditions remain poorly understood. Towards this goal, in this work, we aim to correlate the human ocular perceptions with visual hallucinations, and map them to their cerebral origins. An fMRI study was performed to examine the visual cortical areas including the striate, parastriate and peristriate cortex in the occipital lobe of the human brain. 24 healthy subjects were enrolled and four visual patterns including hallucination circle (HCC), hallucination fan (HCF), retinotopy circle (RTC) and retinotopy cross (RTX) were used towards registering their impact in the aforementioned visual related areas. One-way analysis of variance was used to evaluate the significance of difference between induced activations. Multinomial regression and and K-means were used to cluster activation patterns in visual areas of the brain. Significant activations were observed in the visual cortex as a result of stimulus presentation. The responses induced by visual stimuli were resolved to Brodmann areas 17, 18 and 19. Activation data clustered into independent and mutually exclusive clusters with HCC registering higher activations as compared to HCF, RTC and RTX. We conclude that small circular objects, in rotation, tend to leave greater hallucinating impressions in the visual region. The similarity between observed activation patterns and those reported in conditions such as epilepsy and visual hallucinations can help elucidate the cortical mechanisms underlying these conditions. Trial Registration 1121_GWJUNG.

  9. Sensorimotor Learning: Neurocognitive Mechanisms and Individual Differences.

    Science.gov (United States)

    Seidler, R D; Carson, R G

    2017-07-13

    Here we provide an overview of findings and viewpoints on the mechanisms of sensorimotor learning presented at the 2016 Biomechanics and Neural Control of Movement (BANCOM) conference in Deer Creek, OH. This field has shown substantial growth in the past couple of decades. For example it is now well accepted that neural systems outside of primary motor pathways play a role in learning. Frontoparietal and anterior cingulate networks contribute to sensorimotor adaptation, reflecting strategic aspects of exploration and learning. Longer term training results in functional and morphological changes in primary motor and somatosensory cortices. Interestingly, re-engagement of strategic processes once a skill has become well learned may disrupt performance. Efforts to predict individual differences in learning rate have enhanced our understanding of the neural, behavioral, and genetic factors underlying skilled human performance. Access to genomic analyses has dramatically increased over the past several years. This has enhanced our understanding of cellular processes underlying the expression of human behavior, including involvement of various neurotransmitters, receptors, and enzymes. Surprisingly our field has been slow to adopt such approaches in studying neural control, although this work does require much larger sample sizes than are typically used to investigate skill learning. We advocate that individual differences approaches can lead to new insights into human sensorimotor performance. Moreover, a greater understanding of the factors underlying the wide range of performance capabilities seen across individuals can promote personalized medicine and refinement of rehabilitation strategies, which stand to be more effective than "one size fits all" treatments.

  10. The complexity of the calretinin-expressing progenitors in the human cerebral cortex

    Directory of Open Access Journals (Sweden)

    Nevena V Radonjic

    2014-08-01

    Full Text Available The complex structure and function of the cerebral cortex critically depend on the balance of excitation and inhibition provided by the pyramidal projection neurons and GABAergic interneurons, respectively. The calretinin-expressing (CalR+ cell is a subtype of GABAergic cortical interneurons that is more prevalent in humans than in rodents. In rodents, CalR+ interneurons originate in the caudal ganglionic eminence (CGE from Gsx2+ progenitors, but in humans it has been suggested that a subpopulation of CalR+ cells can also be generated in the cortical ventricular/subventricular zone (VZ/SVZ. The progenitors for cortically generated CalR+ subpopulation in primates are not yet characterized. Hence, the aim of this study was to identify patterns of expression of the transcription factors (TFs that commit cortical stem cells to the CalR fate, with a focus on Gsx2. First, we studied the expression of Gsx2 and its downstream effectors, Ascl1 and Sp8 in the cortical regions of the fetal human forebrain at midgestation. Next, we established that a subpopulation of cells expressing these TFs are proliferating in the cortical SVZ, and can be co-labeled with CalR. The presence and proliferation of Gsx2+ cells, not only in the ventral telencephalon (GE as previously reported, but also in the cerebral cortex suggests cortical origin of a subpopulation of CalR+ neurons in humans. In vitro treatment of human cortical progenitors with Sonic hedgehog (Shh, an important morphogen in the specification of interneurons, decreased levels of Ascl1 and Sp8 proteins, but did not affect Gsx2 levels. Taken together, our ex-vivo and in vitro results on human fetal brain suggest complex endogenous and exogenous regulation of TFs implied in the specification of different subtypes of CalR+ cortical interneurons.

  11. Decoding intention at sensorimotor timescales.

    Directory of Open Access Journals (Sweden)

    Mathew Salvaris

    Full Text Available The ability to decode an individual's intentions in real time has long been a 'holy grail' of research on human volition. For example, a reliable method could be used to improve scientific study of voluntary action by allowing external probe stimuli to be delivered at different moments during development of intention and action. Several Brain Computer Interface applications have used motor imagery of repetitive actions to achieve this goal. These systems are relatively successful, but only if the intention is sustained over a period of several seconds; much longer than the timescales identified in psychophysiological studies for normal preparation for voluntary action. We have used a combination of sensorimotor rhythms and motor imagery training to decode intentions in a single-trial cued-response paradigm similar to those used in human and non-human primate motor control research. Decoding accuracy of over 0.83 was achieved with twelve participants. With this approach, we could decode intentions to move the left or right hand at sub-second timescales, both for instructed choices instructed by an external stimulus and for free choices generated intentionally by the participant. The implications for volition are considered.

  12. Human Language and Sensorimotor Contingency

    DEFF Research Database (Denmark)

    Cowley, Stephen

    2014-01-01

    Using the monumental work of figures like Bloomfield (1933), Harris (1951) and Chomsky (1965), scientific linguistics has often been centrally concerned with verbal patterns. Yet such views have even older roots. Ever since writing systems first arose in Sumeria, what people do as they talk has...

  13. Tuning In to Sound: Frequency-Selective Attentional Filter in Human Primary Auditory Cortex

    Science.gov (United States)

    Da Costa, Sandra; van der Zwaag, Wietske; Miller, Lee M.; Clarke, Stephanie

    2013-01-01

    Cocktail parties, busy streets, and other noisy environments pose a difficult challenge to the auditory system: how to focus attention on selected sounds while ignoring others? Neurons of primary auditory cortex, many of which are sharply tuned to sound frequency, could help solve this problem by filtering selected sound information based on frequency-content. To investigate whether this occurs, we used high-resolution fMRI at 7 tesla to map the fine-scale frequency-tuning (1.5 mm isotropic resolution) of primary auditory areas A1 and R in six human participants. Then, in a selective attention experiment, participants heard low (250 Hz)- and high (4000 Hz)-frequency streams of tones presented at the same time (dual-stream) and were instructed to focus attention onto one stream versus the other, switching back and forth every 30 s. Attention to low-frequency tones enhanced neural responses within low-frequency-tuned voxels relative to high, and when attention switched the pattern quickly reversed. Thus, like a radio, human primary auditory cortex is able to tune into attended frequency channels and can switch channels on demand. PMID:23365225

  14. Plasticity in the Human Visual Cortex: An Ophthalmology-Based Perspective

    Science.gov (United States)

    Rosa, Andreia Martins; Silva, Maria Fátima; Murta, Joaquim

    2013-01-01

    Neuroplasticity refers to the ability of the brain to reorganize the function and structure of its connections in response to changes in the environment. Adult human visual cortex shows several manifestations of plasticity, such as perceptual learning and adaptation, working under the top-down influence of attention. Plasticity results from the interplay of several mechanisms, including the GABAergic system, epigenetic factors, mitochondrial activity, and structural remodeling of synaptic connectivity. There is also a downside of plasticity, that is, maladaptive plasticity, in which there are behavioral losses resulting from plasticity changes in the human brain. Understanding plasticity mechanisms could have major implications in the diagnosis and treatment of ocular diseases, such as retinal disorders, cataract and refractive surgery, amblyopia, and in the evaluation of surgical materials and techniques. Furthermore, eliciting plasticity could open new perspectives in the development of strategies that trigger plasticity for better medical and surgical outcomes. PMID:24205505

  15. Plasticity in the Human Visual Cortex: An Ophthalmology-Based Perspective

    Directory of Open Access Journals (Sweden)

    Andreia Martins Rosa

    2013-01-01

    Full Text Available Neuroplasticity refers to the ability of the brain to reorganize the function and structure of its connections in response to changes in the environment. Adult human visual cortex shows several manifestations of plasticity, such as perceptual learning and adaptation, working under the top-down influence of attention. Plasticity results from the interplay of several mechanisms, including the GABAergic system, epigenetic factors, mitochondrial activity, and structural remodeling of synaptic connectivity. There is also a downside of plasticity, that is, maladaptive plasticity, in which there are behavioral losses resulting from plasticity changes in the human brain. Understanding plasticity mechanisms could have major implications in the diagnosis and treatment of ocular diseases, such as retinal disorders, cataract and refractive surgery, amblyopia, and in the evaluation of surgical materials and techniques. Furthermore, eliciting plasticity could open new perspectives in the development of strategies that trigger plasticity for better medical and surgical outcomes.

  16. Encoding of frequency-modulation (FM) rates in human auditory cortex.

    Science.gov (United States)

    Okamoto, Hidehiko; Kakigi, Ryusuke

    2015-12-14

    Frequency-modulated sounds play an important role in our daily social life. However, it currently remains unclear whether frequency modulation rates affect neural activity in the human auditory cortex. In the present study, using magnetoencephalography, we investigated the auditory evoked N1m and sustained field responses elicited by temporally repeated and superimposed frequency-modulated sweeps that were matched in the spectral domain, but differed in frequency modulation rates (1, 4, 16, and 64 octaves per sec). The results obtained demonstrated that the higher rate frequency-modulated sweeps elicited the smaller N1m and the larger sustained field responses. Frequency modulation rate had a significant impact on the human brain responses, thereby providing a key for disentangling a series of natural frequency-modulated sounds such as speech and music.

  17. Direct electrical stimulation of human cortex evokes high gamma activity that predicts conscious somatosensory perception

    Science.gov (United States)

    Muller, Leah; Rolston, John D.; Fox, Neal P.; Knowlton, Robert; Rao, Vikram R.; Chang, Edward F.

    2018-04-01

    Objective. Direct electrical stimulation (DES) is a clinical gold standard for human brain mapping and readily evokes conscious percepts, yet the neurophysiological changes underlying these percepts are not well understood. Approach. To determine the neural correlates of DES, we stimulated the somatosensory cortex of ten human participants at frequency-amplitude combinations that both elicited and failed to elicit conscious percepts, meanwhile recording neural activity directly surrounding the stimulation site. We then compared the neural activity of perceived trials to that of non-perceived trials. Main results. We found that stimulation evokes distributed high gamma activity, which correlates with conscious perception better than stimulation parameters themselves. Significance. Our findings suggest that high gamma activity is a reliable biomarker for perception evoked by both natural and electrical stimuli.

  18. Frequency-specific attentional modulation in human primary auditory cortex and midbrain.

    Science.gov (United States)

    Riecke, Lars; Peters, Judith C; Valente, Giancarlo; Poser, Benedikt A; Kemper, Valentin G; Formisano, Elia; Sorger, Bettina

    2018-07-01

    Paying selective attention to an audio frequency selectively enhances activity within primary auditory cortex (PAC) at the tonotopic site (frequency channel) representing that frequency. Animal PAC neurons achieve this 'frequency-specific attentional spotlight' by adapting their frequency tuning, yet comparable evidence in humans is scarce. Moreover, whether the spotlight operates in human midbrain is unknown. To address these issues, we studied the spectral tuning of frequency channels in human PAC and inferior colliculus (IC), using 7-T functional magnetic resonance imaging (FMRI) and frequency mapping, while participants focused on different frequency-specific sounds. We found that shifts in frequency-specific attention alter the response gain, but not tuning profile, of PAC frequency channels. The gain modulation was strongest in low-frequency channels and varied near-monotonically across the tonotopic axis, giving rise to the attentional spotlight. We observed less prominent, non-tonotopic spatial patterns of attentional modulation in IC. These results indicate that the frequency-specific attentional spotlight in human PAC as measured with FMRI arises primarily from tonotopic gain modulation, rather than adapted frequency tuning. Moreover, frequency-specific attentional modulation of afferent sound processing in human IC seems to be considerably weaker, suggesting that the spotlight diminishes toward this lower-order processing stage. Our study sheds light on how the human auditory pathway adapts to the different demands of selective hearing. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  19. Temporal envelope processing in the human auditory cortex: response and interconnections of auditory cortical areas.

    Science.gov (United States)

    Gourévitch, Boris; Le Bouquin Jeannès, Régine; Faucon, Gérard; Liégeois-Chauvel, Catherine

    2008-03-01

    Temporal envelope processing in the human auditory cortex has an important role in language analysis. In this paper, depth recordings of local field potentials in response to amplitude modulated white noises were used to design maps of activation in primary, secondary and associative auditory areas and to study the propagation of the cortical activity between them. The comparison of activations between auditory areas was based on a signal-to-noise ratio associated with the response to amplitude modulation (AM). The functional connectivity between cortical areas was quantified by the directed coherence (DCOH) applied to auditory evoked potentials. This study shows the following reproducible results on twenty subjects: (1) the primary auditory cortex (PAC), the secondary cortices (secondary auditory cortex (SAC) and planum temporale (PT)), the insular gyrus, the Brodmann area (BA) 22 and the posterior part of T1 gyrus (T1Post) respond to AM in both hemispheres. (2) A stronger response to AM was observed in SAC and T1Post of the left hemisphere independent of the modulation frequency (MF), and in the left BA22 for MFs 8 and 16Hz, compared to those in the right. (3) The activation and propagation features emphasized at least four different types of temporal processing. (4) A sequential activation of PAC, SAC and BA22 areas was clearly visible at all MFs, while other auditory areas may be more involved in parallel processing upon a stream originating from primary auditory area, which thus acts as a distribution hub. These results suggest that different psychological information is carried by the temporal envelope of sounds relative to the rate of amplitude modulation.

  20. Circuit mechanisms of sensorimotor learning

    Science.gov (United States)

    Makino, Hiroshi; Hwang, Eun Jung; Hedrick, Nathan G.; Komiyama, Takaki

    2016-01-01

    SUMMARY The relationship between the brain and the environment is flexible, forming the foundation for our ability to learn. Here we review the current state of our understanding of the modifications in the sensorimotor pathway related to sensorimotor learning. We divide the process in three hierarchical levels with distinct goals: 1) sensory perceptual learning, 2) sensorimotor associative learning, and 3) motor skill learning. Perceptual learning optimizes the representations of important sensory stimuli. Associative learning and the initial phase of motor skill learning are ensured by feedback-based mechanisms that permit trial-and-error learning. The later phase of motor skill learning may primarily involve feedback-independent mechanisms operating under the classic Hebbian rule. With these changes under distinct constraints and mechanisms, sensorimotor learning establishes dedicated circuitry for the reproduction of stereotyped neural activity patterns and behavior. PMID:27883902

  1. A practical guide for the identification of major sulcogyral structures of the human cortex.

    Science.gov (United States)

    Destrieux, Christophe; Terrier, Louis Marie; Andersson, Frédéric; Love, Scott A; Cottier, Jean-Philippe; Duvernoy, Henri; Velut, Stéphane; Janot, Kevin; Zemmoura, Ilyess

    2017-05-01

    The precise sulcogyral localization of cortical lesions is mandatory to improve communication between practitioners and to predict and prevent post-operative deficits. This process, which assumes a good knowledge of the cortex anatomy and a systematic analysis of images, is, nevertheless, sometimes neglected in the neurological and neurosurgical training. This didactic paper proposes a brief overview of the sulcogyral anatomy, using conventional MR-slices, and also reconstructions of the cortical surface after a more or less extended inflation process. This method simplifies the cortical anatomy by removing part of the cortical complexity induced by the folding process, and makes it more understandable. We then reviewed several methods for localizing cortical structures, and proposed a three-step identification: after localizing the lateral, medial or ventro-basal aspect of the hemisphere (step 1), the main interlobar sulci were located to limit the lobes (step 2). Finally, intralobar sulci and gyri were identified (step 3) thanks to the same set of rules. This paper does not propose any new identification method but should be regarded as a set of practical guidelines, useful in daily clinical practice, for detecting the main sulci and gyri of the human cortex.

  2. Right hemispheric dominance of visual phenomena evoked by intracerebral stimulation of the human visual cortex.

    Science.gov (United States)

    Jonas, Jacques; Frismand, Solène; Vignal, Jean-Pierre; Colnat-Coulbois, Sophie; Koessler, Laurent; Vespignani, Hervé; Rossion, Bruno; Maillard, Louis

    2014-07-01

    Electrical brain stimulation can provide important information about the functional organization of the human visual cortex. Here, we report the visual phenomena evoked by a large number (562) of intracerebral electrical stimulations performed at low-intensity with depth electrodes implanted in the occipito-parieto-temporal cortex of 22 epileptic patients. Focal electrical stimulation evoked primarily visual hallucinations with various complexities: simple (spot or blob), intermediary (geometric forms), or complex meaningful shapes (faces); visual illusions and impairments of visual recognition were more rarely observed. With the exception of the most posterior cortical sites, the probability of evoking a visual phenomenon was significantly higher in the right than the left hemisphere. Intermediary and complex hallucinations, illusions, and visual recognition impairments were almost exclusively evoked by stimulation in the right hemisphere. The probability of evoking a visual phenomenon decreased substantially from the occipital pole to the most anterior sites of the temporal lobe, and this decrease was more pronounced in the left hemisphere. The greater sensitivity of the right occipito-parieto-temporal regions to intracerebral electrical stimulation to evoke visual phenomena supports a predominant role of right hemispheric visual areas from perception to recognition of visual forms, regardless of visuospatial and attentional factors. Copyright © 2013 Wiley Periodicals, Inc.

  3. Attention Determines Contextual Enhancement versus Suppression in Human Primary Visual Cortex.

    Science.gov (United States)

    Flevaris, Anastasia V; Murray, Scott O

    2015-09-02

    Neural responses in primary visual cortex (V1) depend on stimulus context in seemingly complex ways. For example, responses to an oriented stimulus can be suppressed when it is flanked by iso-oriented versus orthogonally oriented stimuli but can also be enhanced when attention is directed to iso-oriented versus orthogonal flanking stimuli. Thus the exact same contextual stimulus arrangement can have completely opposite effects on neural responses-in some cases leading to orientation-tuned suppression and in other cases leading to orientation-tuned enhancement. Here we show that stimulus-based suppression and enhancement of fMRI responses in humans depends on small changes in the focus of attention and can be explained by a model that combines feature-based attention with response normalization. Neurons in the primary visual cortex (V1) respond to stimuli within a restricted portion of the visual field, termed their "receptive field." However, neuronal responses can also be influenced by stimuli that surround a receptive field, although the nature of these contextual interactions and underlying neural mechanisms are debated. Here we show that the response in V1 to a stimulus in the same context can either be suppressed or enhanced depending on the focus of attention. We are able to explain the results using a simple computational model that combines two well established properties of visual cortical responses: response normalization and feature-based enhancement. Copyright © 2015 the authors 0270-6474/15/3512273-08$15.00/0.

  4. Human perception of electrical stimulation on the surface of somatosensory cortex.

    Directory of Open Access Journals (Sweden)

    Shivayogi V Hiremath

    Full Text Available Recent advancement in electrocorticography (ECoG-based brain-computer interface technology has sparked a new interest in providing somatosensory feedback using ECoG electrodes, i.e., cortical surface electrodes. We conducted a 28-day study of cortical surface stimulation in an individual with arm paralysis due to brachial plexus injury to examine the sensation produced by electrical stimulation of the somatosensory cortex. A high-density ECoG grid was implanted over the somatosensory and motor cortices. Stimulation through cortical surface electrodes over the somatosensory cortex successfully elicited arm and hand sensations in our participant with chronic paralysis. There were three key findings. First, the intensity of perceived sensation increased monotonically with both pulse amplitude and pulse frequency. Second, changing pulse width changed the type of sensation based on qualitative description provided by the human participant. Third, the participant could distinguish between stimulation applied to two neighboring cortical surface electrodes, 4.5 mm center-to-center distance, for three out of seven electrode pairs tested. Taken together, we found that it was possible to modulate sensation intensity, sensation type, and evoke sensations across a range of locations from the fingers to the upper arm using different stimulation electrodes even in an individual with chronic impairment of somatosensory function. These three features are essential to provide effective somatosensory feedback for neuroprosthetic applications.

  5. Inducing homeostatic-like plasticity in human motor cortex through converging corticocortical inputs

    DEFF Research Database (Denmark)

    Pötter-Nerger, Monika; Fischer, Sarah; Mastroeni, Claudia

    2009-01-01

    Transcranial stimulation techniques have revealed homeostatic-like metaplasticity in the hand area of the human primary motor cortex (M1(HAND)) that controls stimulation-induced changes in corticospinal excitability. Here we combined two interventional protocols that induce long-term depression......TMS) of the left dorsal premotor cortex (PMD) was first applied to produce an LTP-like increase (5 Hz rTMS) or LTD-like decrease (1 Hz rTMS) in corticospinal excitability in left M1(HAND) via premotor-to-motor inputs. Following PMD rTMS, paired-associative stimulation (PAS) was applied to the right median nerve...... and left M1(HAND) to induce spike-time-dependent plasticity in sensory-to-motor inputs to left M1(HAND). We adjusted the interstimulus interval to the N20 latency of the median nerve somatosensory-evoked cortical potential to produce an LTP-like increase (PAS(N20+2ms)) or an LTD-like decrease (PAS(N20-5ms...

  6. Lipid alterations in lipid rafts from Alzheimer's disease human brain cortex.

    Science.gov (United States)

    Martín, Virginia; Fabelo, Noemí; Santpere, Gabriel; Puig, Berta; Marín, Raquel; Ferrer, Isidre; Díaz, Mario

    2010-01-01

    Lipid rafts are membrane microdomains intimately associated with cell signaling. These biochemical microstructures are characterized by their high contents of sphingolipids, cholesterol and saturated fatty acids and a reduced content of polyunsaturated fatty acids (PUFA). Here, we have purified lipid rafts of human frontal brain cortex from normal and Alzheimer's disease (AD) and characterized their biochemical lipid composition. The results revealed that lipid rafts from AD brains exhibit aberrant lipid profiles compared to healthy brains. In particular, lipid rafts from AD brains displayed abnormally low levels of n-3 long chain polyunsaturated fatty acids (LCPUFA, mainly 22:6n-3, docosahexaenoic acid) and monoenes (mainly 18:1n-9, oleic acid), as well as reduced unsaturation and peroxidability indexes. Also, multiple relationships between phospholipids and fatty acids were altered in AD lipid rafts. Importantly, no changes were observed in the mole percentage of lipid classes and fatty acids in rafts from normal brains throughout the lifespan (24-85 years). These indications point to the existence of homeostatic mechanisms preserving lipid raft status in normal frontal cortex. The disruption of such mechanisms in AD brains leads to a considerable increase in lipid raft order and viscosity, which may explain the alterations in lipid raft signaling observed in AD.

  7. Characterization of visual percepts evoked by noninvasive stimulation of the human posterior parietal cortex.

    Directory of Open Access Journals (Sweden)

    Peter J Fried

    Full Text Available Phosphenes are commonly evoked by transcranial magnetic stimulation (TMS to study the functional organization, connectivity, and excitability of the human visual brain. For years, phosphenes have been documented only from stimulating early visual areas (V1-V3 and a handful of specialized visual regions (V4, V5/MT+ in occipital cortex. Recently, phosphenes were reported after applying TMS to a region of posterior parietal cortex involved in the top-down modulation of visuo-spatial processing. In the present study, we systematically characterized parietal phosphenes to determine if they are generated directly by local mechanisms or emerge through indirect activation of other visual areas. Using technology developed in-house to record the subjective features of phosphenes, we found no systematic differences in the size, shape, location, or frame-of-reference of parietal phosphenes when compared to their occipital counterparts. In a second experiment, discrete deactivation by 1 Hz repetitive TMS yielded a double dissociation: phosphene thresholds increased at the deactivated site without producing a corresponding change at the non-deactivated location. Overall, the commonalities of parietal and occipital phosphenes, and our ability to independently modulate their excitability thresholds, lead us to conclude that they share a common neural basis that is separate from either of the stimulated regions.

  8. GABAA receptor B subunit expression in the superior frontal cortex of human alcoholics

    International Nuclear Information System (INIS)

    Buckley, S.T.; Dodd, P.R.

    2001-01-01

    Full text: Changes in GABA A receptor pharmacology can be ascribed to alterations in expression of specific GABA A receptor subunits. Ethanol is known to be a potent agonist of the GABA A receptor. Chronic abuse of alcohol in humans results in damage of selective brain regions such as the superior frontal cortex (SFC), leading to neuronal cell loss. Studies in our laboratory 1 and elsewhere 2 have shown differences in expression of a number of GABA A receptor subunits in chronic human alcoholism. This suggests that alterations in GABA A receptor composition may be involved in the pathogenesis of alcoholic brain damage. We analysed the expression of the β 1 ,β 2 and β 3 isoforms of the GABA A receptor by a competitive reverse transcription polymerase chain reaction (RT-PCR) technique, which utilised an internal standard (IS) for quantitation. 35 S-dATP was incorporated to enable visualisation of the PCR products. Human brain tissue was obtained at autopsy and stored in 0.32 M sucrose at -80 deg C. Total RNA was extracted from pathologically susceptible and spared regions, SFC and motor cortex respectively,of 22 control and 22 alcoholic patients. 1 μg of total RNA from each sample was co-amplified with 0.5 pg of IS and a ratio determined. A standard consisting of known amounts of β 1 cRNA titrated against 0.5 pg of IS enabled a standard curve to be generated for quantitation of each unknown sample. The samples were subjected to polyacrylamide gel electrophoresis and the dried gel exposed to a phosphorimager screen. Data analysis was performed using the ImageQuant program. Initial results indicate that there is a reduction in expression of all the β transcripts in alcoholics when compared with controls, which supports the hypothesis that the GABA A receptor is altered by alcohol abuse. Supported by NHMRC. Copyright (2001) Australian Neuroscience Society

  9. Context-dependent spatially periodic activity in the human entorhinal cortex.

    Science.gov (United States)

    Nadasdy, Zoltan; Nguyen, T Peter; Török, Ágoston; Shen, Jason Y; Briggs, Deborah E; Modur, Pradeep N; Buchanan, Robert J

    2017-04-25

    The spatially periodic activity of grid cells in the entorhinal cortex (EC) of the rodent, primate, and human provides a coordinate system that, together with the hippocampus, informs an individual of its location relative to the environment and encodes the memory of that location. Among the most defining features of grid-cell activity are the 60° rotational symmetry of grids and preservation of grid scale across environments. Grid cells, however, do display a limited degree of adaptation to environments. It remains unclear if this level of environment invariance generalizes to human grid-cell analogs, where the relative contribution of visual input to the multimodal sensory input of the EC is significantly larger than in rodents. Patients diagnosed with nontractable epilepsy who were implanted with entorhinal cortical electrodes performing virtual navigation tasks to memorized locations enabled us to investigate associations between grid-like patterns and environment. Here, we report that the activity of human entorhinal cortical neurons exhibits adaptive scaling in grid period, grid orientation, and rotational symmetry in close association with changes in environment size, shape, and visual cues, suggesting scale invariance of the frequency, rather than the wavelength, of spatially periodic activity. Our results demonstrate that neurons in the human EC represent space with an enhanced flexibility relative to neurons in rodents because they are endowed with adaptive scalability and context dependency.

  10. Dosage-dependent non-linear effect of L-dopa on human motor cortex plasticity.

    Science.gov (United States)

    Monte-Silva, Katia; Liebetanz, David; Grundey, Jessica; Paulus, Walter; Nitsche, Michael A

    2010-09-15

    The neuromodulator dopamine affects learning and memory formation and their likely physiological correlates, long-term depression and potentiation, in animals and humans. It is known from animal experiments that dopamine exerts a dosage-dependent, inverted U-shaped effect on these functions. However, this has not been explored in humans so far. In order to reveal a non-linear dose-dependent effect of dopamine on cortical plasticity in humans, we explored the impact of 25, 100 and 200 mg of L-dopa on transcranial direct current (tDCS)-induced plasticity in twelve healthy human subjects. The primary motor cortex served as a model system, and plasticity was monitored by motor evoked potential amplitudes elicited by transcranial magnetic stimulation. As compared to placebo medication, low and high dosages of L-dopa abolished facilitatory as well as inhibitory plasticity, whereas the medium dosage prolonged inhibitory plasticity, and turned facilitatory plasticity into inhibition. Thus the results show clear non-linear, dosage-dependent effects of dopamine on both facilitatory and inhibitory plasticity, and support the assumption of the importance of a specific dosage of dopamine optimally suited to improve plasticity. This might be important for the therapeutic application of dopaminergic agents, especially for rehabilitative purposes, and explain some opposing results in former studies.

  11. Functional specializations in human cerebral cortex analyzed using the Visible Man surface-based atlas

    Science.gov (United States)

    Drury, H. A.; Van Essen, D. C.

    1997-01-01

    We used surface-based representations to analyze functional specializations in the human cerebral cortex. A computerized reconstruction of the cortical surface of the Visible Man digital atlas was generated and transformed to the Talairach coordinate system. This surface was also flattened and used to establish a surface-based coordinate system that respects the topology of the cortical sheet. The linkage between two-dimensional and three-dimensional representations allows the locations of published neuroimaging activation foci to be stereotaxically projected onto the Visible Man cortical flat map. An analysis of two activation studies related to the hearing and reading of music and of words illustrates how this approach permits the systematic estimation of the degree of functional segregation and of potential functional overlap for different aspects of sensory processing.

  12. Functional reorganization of human motor cortex after unaffected side C7 nerve root transposition

    International Nuclear Information System (INIS)

    Gao Gejun; Feng Xiaoyuan; Xu Wendong; Gu Yudong; Tang Weijun; Sun Guixin; Li Ke; Li Yuan; Geng Daoying

    2006-01-01

    Objective: To assess the characteristics of neuronal activity in human motor cortex after the seventh cervical nerve root transposition of the unaffected side by using functional MRI (fMRI). Methods: Thirteen patients who accepted the seventh cervical nerve root transposition of the unaffected side, due to total brachial plexus traction injury diagnosed by manifestation and operation, were examined retrospectively by using fMRI. 10 patients were injured on the left side and 3 on the right side. According to functional recovery of the affected hand, all subjects can be divided into 2 groups. The patients of the first group could not move the affected hand voluntarily. The patients of the second group could move the affected hand self-determined. 12 healthy volunteer's were also involved in this study as control. The fMRI examinations were performed by using echo-planer BOLD sequence. Then the SPM 99 software was used for post-processing. Results: The neuronal activation induced by the movement of both unaffected and affected upper' limb was seen in the contralateral PMC in all patients; Neuronal activation in the ipsilateral PMC evoked by movement of the unaffected extremity was seen in 10 cases, and induced by movement of the affected limb was seen in 7 cases. In the first group, the sharp of clusters in the contralateral PMC resulted by movement of the unaffected extremity showed normal in 9 eases, the average size of clusters resulted by the unaffected hand was 3159 (voxel), and resulted by the unaffected shoulder was 1746(voxel). The sharp of clusters in the contralateral PMC resulted by the affected shoulder or hand were revealed enlargement in 6 cases of each. In the second group, 1 case showed neuronal activation induced by movement of the affected limb in the PMC in both sides of motor cortex, and 2 cases showed neuronal activation in the contralateral PMC. Conclusions: Peripheral nerve injury was able to cause changes of motor cortex in human brain

  13. Stimulus uncertainty enhances long-term potentiation-like plasticity in human motor cortex.

    Science.gov (United States)

    Sale, Martin V; Nydam, Abbey S; Mattingley, Jason B

    2017-03-01

    Plasticity can be induced in human cortex using paired associative stimulation (PAS), which repeatedly and predictably pairs a peripheral electrical stimulus with transcranial magnetic stimulation (TMS) to the contralateral motor region. Many studies have reported small or inconsistent effects of PAS. Given that uncertain stimuli can promote learning, the predictable nature of the stimulation in conventional PAS paradigms might serve to attenuate plasticity induction. Here, we introduced stimulus uncertainty into the PAS paradigm to investigate if it can boost plasticity induction. Across two experimental sessions, participants (n = 28) received a modified PAS paradigm consisting of a random combination of 90 paired stimuli and 90 unpaired (TMS-only) stimuli. Prior to each of these stimuli, participants also received an auditory cue which either reliably predicted whether the upcoming stimulus was paired or unpaired (no uncertainty condition) or did not predict the upcoming stimulus (maximum uncertainty condition). Motor evoked potentials (MEPs) evoked from abductor pollicis brevis (APB) muscle quantified cortical excitability before and after PAS. MEP amplitude increased significantly 15 min following PAS in the maximum uncertainty condition. There was no reliable change in MEP amplitude in the no uncertainty condition, nor between post-PAS MEP amplitudes across the two conditions. These results suggest that stimulus uncertainty may provide a novel means to enhance plasticity induction with the PAS paradigm in human motor cortex. To provide further support to the notion that stimulus uncertainty and prediction error promote plasticity, future studies should further explore the time course of these changes, and investigate what aspects of stimulus uncertainty are critical in boosting plasticity. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. How learning might strengthen existing visual object representations in human object-selective cortex.

    Science.gov (United States)

    Brants, Marijke; Bulthé, Jessica; Daniels, Nicky; Wagemans, Johan; Op de Beeck, Hans P

    2016-02-15

    Visual object perception is an important function in primates which can be fine-tuned by experience, even in adults. Which factors determine the regions and the neurons that are modified by learning is still unclear. Recently, it was proposed that the exact cortical focus and distribution of learning effects might depend upon the pre-learning mapping of relevant functional properties and how this mapping determines the informativeness of neural units for the stimuli and the task to be learned. From this hypothesis we would expect that visual experience would strengthen the pre-learning distributed functional map of the relevant distinctive object properties. Here we present a first test of this prediction in twelve human subjects who were trained in object categorization and differentiation, preceded and followed by a functional magnetic resonance imaging session. Specifically, training increased the distributed multi-voxel pattern information for trained object distinctions in object-selective cortex, resulting in a generalization from pre-training multi-voxel activity patterns to after-training activity patterns. Simulations show that the increased selectivity combined with the inter-session generalization is consistent with a training-induced strengthening of a pre-existing selectivity map. No training-related neural changes were detected in other regions. In sum, training to categorize or individuate objects strengthened pre-existing representations in human object-selective cortex, providing a first indication that the neuroanatomical distribution of learning effects depends upon the pre-learning mapping of visual object properties. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Metaplasticity in human primary somatosensory cortex: effects on physiology and tactile perception.

    Science.gov (United States)

    Jones, Christina B; Lulic, Tea; Bailey, Aaron Z; Mackenzie, Tanner N; Mi, Yi Qun; Tommerdahl, Mark; Nelson, Aimee J

    2016-05-01

    Theta-burst stimulation (TBS) over human primary motor cortex evokes plasticity and metaplasticity, the latter contributing to the homeostatic balance of excitation and inhibition. Our knowledge of TBS-induced effects on primary somatosensory cortex (SI) is limited, and it is unknown whether TBS induces metaplasticity within human SI. Sixteen right-handed participants (6 females, mean age 23 yr) received two TBS protocols [continuous TBS (cTBS) and intermittent TBS (iTBS)] delivered in six different combinations over SI in separate sessions. TBS protocols were delivered at 30 Hz and were as follows: a single cTBS protocol, a single iTBS protocol, cTBS followed by cTBS, iTBS followed by iTBS, cTBS followed by iTBS, and iTBS followed by cTBS. Measures included the amplitudes of the first and second somatosensory evoked potentials (SEPs) via median nerve stimulation, their paired-pulse ratio (PPR), and temporal order judgment (TOJ). Dependent measures were obtained before TBS and at 5, 25, 50, and 90 min following stimulation. Results indicate similar effects following cTBS and iTBS; increased amplitudes of the second SEP and PPR without amplitude changes to SEP 1, and impairments in TOJ. Metaplasticity was observed such that TOJ impairments following a single cTBS protocol were abolished following consecutive cTBS protocols. Additionally, consecutive iTBS protocols altered the time course of effects when compared with a single iTBS protocol. In conclusion, 30-Hz cTBS and iTBS protocols delivered in isolation induce effects consistent with a TBS-induced reduction in intracortical inhibition within SI. Furthermore, cTBS- and iTBS-induced metaplasticity appear to follow homeostatic and nonhomeostatic rules, respectively. Copyright © 2016 the American Physiological Society.

  16. Immunocytochemical expression of monocarboxylate transporters in the human visual cortex at midgestation.

    Science.gov (United States)

    Fayol, Laurence; Baud, Olivier; Monier, Anne; Pellerin, Luc; Magistretti, Pierre; Evrard, Philippe; Verney, Catherine

    2004-01-31

    Lactate and the other monocarboxylates are a major energy source for the developing brain. We investigated the immunocytochemical expression of two monocarboxylate transporters, MCT1 and MCT2, in the human visual cortex between 13 and 26 post-ovulatory weeks. We used immunoperoxidase and immunofluorescence techniques to determine whether these transporters co-localized with markers for blood vessels (CD34), neurons (microtubule-associated protein 2 [MAP2], SMI 311), radial glia (vimentin), or astrocytes (glial fibrillary acidic protein [GFAP], S100beta protein). MCT1 immunoreactivity was visible in blood vessel walls as early as the 13th week of gestation mainly in the cortical plate and subplate. At this stage, less than 10% of vessels in the ventricular layer expressed MCT1, whereas all blood vessels walls showed this immunoreactivity at the 26th gestational week. Starting at the 19th week of gestation, sparse MCT1 positive cell bodies were detected, some of them co-localized with MAP2 immunoreactivity. MCT2 immunoreactivity was noted in astrocytic cell bodies from week 19 and spread subsequently to the astrocyte end-feet in contact with blood vessels. MCTs immunoreactivities were most marked in the subplate and deep cortical plate, where the most differentiated neurons were located. Our findings suggest that monocarboxylate trafficking between vessels (MCT1), astrocytes (MCT2) and some postmitotic neurons (MCT1) could develop gradually toward 20 gestational weeks (g.w.). These data suggest that lactate or other monocarboxylates could represent a significant energy source for the human visual cortex at this early stage.

  17. Dorsolateral Prefrontal Cortex GABA Concentration in Humans Predicts Working Memory Load Processing Capacity.

    Science.gov (United States)

    Yoon, Jong H; Grandelis, Anthony; Maddock, Richard J

    2016-11-16

    The discovery of neural mechanisms of working memory (WM) would significantly enhance our understanding of complex human behaviors and guide treatment development for WM-related impairments found in neuropsychiatric conditions and aging. Although the dorsolateral prefrontal cortex (DLPFC) has long been considered critical for WM, we still know little about the neural elements and pathways within the DLPFC that support WM in humans. In this study, we tested whether an individual's DLPFC gamma-aminobutryic acid (GABA) content predicts individual differences in WM task performance using a novel behavioral approach. Twenty-three healthy adults completed a task that measured the unique contribution of major WM components (memory load, maintenance, and distraction resistance) to performance. This was done to address the possibility that components have differing GABA dependencies and the failure to parse WM into components would lead to missing true associations with GABA. The subjects then had their DLPFC GABA content measured by single-voxel proton magnetic spectroscopy. We found that individuals with lower DLPFC GABA showed greater performance degradation with higher load, accounting for 31% of variance, p (corrected) = 0.015. This relationship was component, neurochemical, and brain region specific. DLPFC GABA content did not predict performance sensitivity to other components tested; DLPFC glutamate + glutamine and visual cortical GABA content did not predict load sensitivity. These results confirm the involvement of DLPFC GABA in WM load processing in humans and implicate factors controlling DLPFC GABA content in the neural mechanisms of WM and its impairments. This study demonstrated for the first time that the amount of gamma-aminobutryic acid (GABA), the major inhibitory neurotransmitter of the brain, in an individual's prefrontal cortex predicts working memory (WM) task performance. Given that WM is required for many of the most characteristic cognitive and

  18. Individual differences in laughter perception reveal roles for mentalizing and sensorimotor systems in the evaluation of emotional authenticity.

    Science.gov (United States)

    McGettigan, C; Walsh, E; Jessop, R; Agnew, Z K; Sauter, D A; Warren, J E; Scott, S K

    2015-01-01

    Humans express laughter differently depending on the context: polite titters of agreement are very different from explosions of mirth. Using functional MRI, we explored the neural responses during passive listening to authentic amusement laughter and controlled, voluntary laughter. We found greater activity in anterior medial prefrontal cortex (amPFC) to the deliberate, Emitted Laughs, suggesting an obligatory attempt to determine others' mental states when laughter is perceived as less genuine. In contrast, passive perception of authentic Evoked Laughs was associated with greater activity in bilateral superior temporal gyri. An individual differences analysis found that greater accuracy on a post hoc test of authenticity judgments of laughter predicted the magnitude of passive listening responses to laughter in amPFC, as well as several regions in sensorimotor cortex (in line with simulation accounts of emotion perception). These medial prefrontal and sensorimotor sites showed enhanced positive connectivity with cortical and subcortical regions during listening to involuntary laughter, indicating a complex set of interacting systems supporting the automatic emotional evaluation of heard vocalizations. © The Author 2013. Published by Oxford University Press.

  19. Our Faces in the Dog's Brain: Functional Imaging Reveals Temporal Cortex Activation during Perception of Human Faces.

    Directory of Open Access Journals (Sweden)

    Laura V Cuaya

    Full Text Available Dogs have a rich social relationship with humans. One fundamental aspect of it is how dogs pay close attention to human faces in order to guide their behavior, for example, by recognizing their owner and his/her emotional state using visual cues. It is well known that humans have specific brain regions for the processing of other human faces, yet it is unclear how dogs' brains process human faces. For this reason, our study focuses on describing the brain correlates of perception of human faces in dogs using functional magnetic resonance imaging (fMRI. We trained seven domestic dogs to remain awake, still and unrestrained inside an MRI scanner. We used a visual stimulation paradigm with block design to compare activity elicited by human faces against everyday objects. Brain activity related to the perception of faces changed significantly in several brain regions, but mainly in the bilateral temporal cortex. The opposite contrast (i.e., everyday objects against human faces showed no significant brain activity change. The temporal cortex is part of the ventral visual pathway, and our results are consistent with reports in other species like primates and sheep, that suggest a high degree of evolutionary conservation of this pathway for face processing. This study introduces the temporal cortex as candidate to process human faces, a pillar of social cognition in dogs.

  20. Repetitive tactile stimulation changes resting-state functional connectivity – implications for treatment of sensorimotor decline

    Directory of Open Access Journals (Sweden)

    Frank eFreyer

    2012-05-01

    Full Text Available Neurological disorders and physiological aging can lead to a decline of perceptual abilities. In contrast to the conventional therapeutic approach that comprises intensive training and practicing, passive repetitive sensory stimulation (RSS has recently gained increasing attention as an alternative to countervail the sensory decline by improving perceptual abilities without the need of active participation. A particularly effective type of high-frequency RSS, utilizing Hebbian learning principles, improves perceptual acuity as well as sensorimotor functions and has been successfully applied to treat chronic stroke patients and elderly subjects. High-frequency RSS has been shown to induce plastic changes of somatosensory cortex such as representational map reorganization, but its impact on the brain’s ongoing network activity and resting-state functional connectivity has not been investigated so far. Here, we applied high-frequency RSS in healthy human subjects and analyzed resting state Electroencephalography (EEG functional connectivity patterns before and after RSS by means of imaginary coherency (ImCoh, a frequency-specific connectivity measure which is known to reduce overestimation biases due to volume conduction and common reference. Thirty minutes of passive high-frequency RSS lead to significant ImCoh-changes of the resting state mu-rhythm in the individual upper alpha frequency band within distributed sensory and motor cortical areas. These stimulation induced distributed functional connectivity changes likely underlie the previously observed improvement in sensorimotor integration.

  1. Sensorimotor modulation of mood and depression: In search of an optimal mode of stimulation

    Directory of Open Access Journals (Sweden)

    RESIT eCANBEYLI

    2013-07-01

    Full Text Available Depression involves a dysfunction in an affective fronto-limbic circuitry including the prefrontal cortices, several limbic structures including the cingulate cortex, the amygdala and the hippocampus as well as the basal ganglia. A major emphasis of research on the etiology and treatment of mood disorders has been to assess the impact of centrally generated (top-down processes impacting the affective fronto-limbic circuitry. The present review shows that peripheral (bottom-up unipolar stimulation via the visual and the auditory modalities as well as by physical exercise modulates mood and depressive symptoms in humans and animals and activates the same central affective neurocircuitry involved in depression. It is proposed that the amygdala serves as a gateway by articulating the mood regulatory sensorimotor stimulation with the central affective circuitry by emotionally labeling and mediating the storage of such emotional events in long-term memory. Since both amelioration and aggravation of mood is shown to be possible by unipolar stimulation, the review suggests that a psychophysical assessment of mood modulation by multi-modal stimulation may uncover mood ameliorative synergisms and serve as adjunctive treatment for depression. Thus, the integrative review not only emphasizes the relevance of investigating the optimal levels of mood regulatory sensorimotor stimulation, but also provides a conceptual springboard for related future research.

  2. Coordinated Expression of Phosphoinositide Metabolic Genes during Development and Aging of Human Dorsolateral Prefrontal Cortex.

    Directory of Open Access Journals (Sweden)

    Stanley I Rapoport

    Full Text Available Phosphoinositides, lipid-signaling molecules, participate in diverse brain processes within a wide metabolic cascade.Gene transcriptional networks coordinately regulate the phosphoinositide cascade during human brain Development and Aging.We used the public BrainCloud database for human dorsolateral prefrontal cortex to examine age-related expression levels of 49 phosphoinositide metabolic genes during Development (0 to 20+ years and Aging (21+ years.We identified three groups of partially overlapping genes in each of the two intervals, with similar intergroup correlations despite marked phenotypic differences between Aging and Development. In each interval, ITPKB, PLCD1, PIK3R3, ISYNA1, IMPA2, INPPL1, PI4KB, and AKT1 are in Group 1, PIK3CB, PTEN, PIK3CA, and IMPA1 in Group 2, and SACM1L, PI3KR4, INPP5A, SYNJ1, and PLCB1 in Group 3. Ten of the genes change expression nonlinearly during Development, suggesting involvement in rapidly changing neuronal, glial and myelination events. Correlated transcription for some gene pairs likely is facilitated by colocalization on the same chromosome band.Stable coordinated gene transcriptional networks regulate brain phosphoinositide metabolic pathways during human Development and Aging.

  3. Neuropeptide Y-immunoreactive neurons in the cerebral cortex of humans and other haplorrhine primates

    Science.gov (United States)

    Raghanti, Mary Ann; Conley, Tiffini; Sudduth, Jessica; Erwin, Joseph M.; Stimpson, Cheryl D.; Hof, Patrick R.; Sherwood, Chet C.

    2012-01-01

    We examined the distribution of neurons immunoreactive for neuropeptide Y (NPY) in the posterior part of the superior temporal cortex (Brodmann's area 22 or area Tpt) of humans and nonhuman haplorrhine primates. NPY has been implicated in learning and memory and the density of NPY-expressing cortical neurons and axons is reduced in depression, bipolar disorder, schizophrenia, and Alzheimer's disease. Due to the role that NPY plays in both cognition and neurodegenerative diseases, we tested the hypothesis that the density of cortical and interstitial neurons expressing NPY was increased in humans relative to other primate species. The study sample included great apes (chimpanzee and gorilla), Old World monkeys (pigtailed macaque, moor macaque, and baboon) and New World monkeys (squirrel monkey and capuchin). Stereologic methods were used to estimate the density of NPY-immunoreactive (-ir) neurons in layers I-VI of area Tpt and the subjacent white matter. Adjacent Nissl-stained sections were used to calculate local densities of all neurons. The ratio of NPY-ir neurons to total neurons within area Tpt and the total density of NPY-ir neurons within the white matter were compared among species. Overall, NPY-ir neurons represented only an average of 0.006% of the total neuron population. While there were significant differences among species, phylogenetic trends in NPY-ir neuron distributions were not observed and humans did not differ from other primates. However, variation among species warrants further investigation into the distribution of this neuromodulator system. PMID:23042407

  4. Structural and functional hyperconnectivity within the sensorimotor system in xenomelia.

    Science.gov (United States)

    Hänggi, Jürgen; Vitacco, Deborah A; Hilti, Leonie M; Luechinger, Roger; Kraemer, Bernd; Brugger, Peter

    2017-03-01

    Xenomelia is a rare condition characterized by the persistent and compulsive desire for the amputation of one or more physically healthy limbs. We highlight the neurological underpinnings of xenomelia by assessing structural and functional connectivity by means of whole-brain connectome and network analyses of regions previously implicated in empirical research in this condition. We compared structural and functional connectivity between 13 xenomelic men with matched controls using diffusion tensor imaging combined with fiber tractography and resting state functional magnetic resonance imaging. Altered connectivity in xenomelia within the sensorimotor system has been predicted. We found subnetworks showing structural and functional hyperconnectivity in xenomelia compared with controls. These subnetworks were lateralized to the right hemisphere and mainly comprised by nodes belonging to the sensorimotor system. In the connectome analyses, the paracentral lobule, supplementary motor area, postcentral gyrus, basal ganglia, and the cerebellum were hyperconnected to each other, whereas in the xenomelia-specific network analyses, hyperconnected nodes have been found in the superior parietal lobule, primary and secondary somatosensory cortex, premotor cortex, basal ganglia, thalamus, and insula. Our study provides empirical evidence of structural and functional hyperconnectivity within the sensorimotor system including those regions that are core for the reconstruction of a coherent body image. Aberrant connectivity is a common response to focal neurological damage. As exemplified here, it may affect different brain regions differentially. Due to the small sample size, our findings must be interpreted cautiously and future studies are needed to elucidate potential associations between hyperconnectivity and limb disownership reported in xenomelia.

  5. The human dorsal premotor cortex facilitates the excitability of ipsilateral primary motor cortex via a short latency cortico-cortical route

    DEFF Research Database (Denmark)

    Groppa, Sergiu; Schlaak, Boris H; Münchau, Alexander

    2012-01-01

    In non-human primates, invasive tracing and electrostimulation studies have identified strong ipsilateral cortico-cortical connections between dorsal premotor- (PMd) and the primary motor cortex (M1(HAND) ). Here, we applied dual-site transcranial magnetic stimulation (dsTMS) to left PMd and M1......(HAND) through specifically designed minicoils to selectively probe ipsilateral PMd-to-M1(HAND) connectivity in humans. A suprathreshold test stimulus (TS) was applied to M1(HAND) producing a motor evoked potential (MEP) of about 0.5 mV in the relaxed right first dorsal interosseus muscle (FDI......) facilitation did not change as a function of CS intensity. Even at higher intensities, the CS alone failed to elicit a MEP or a cortical silent period in the pre-activated FDI, excluding a direct spread of excitation from PMd to M1(HAND). No MEP facilitation was present while CS was applied rostrally over...

  6. Posterior parietal cortex role in a sensorimotor task performance Papel do córtex parietal posterior na realização de uma tarefa sensório-motora

    Directory of Open Access Journals (Sweden)

    Sergio Nader

    2008-06-01

    Full Text Available This study aimed to elucidate electrophysiological and cortical mechanisms involved in anticipatory actions when individuals had to catch balls in free drop; specifically through quantitative electroencephalography (qEEG alpha absolute power changes. The sample was composed for 23 health subjects, both sexes, with ages varying between 25 and 40 years, absence of mental and physical illness, right handed and don't make use of any psychoactive or psychotropic substance at the time of the study. The experiment consisted of a task of catching balls in free drop. The three-way ANOVA analysis demonstrated an interaction between moment and position factors in left parietal posterior cortex (PPC (p=0.001. Through the experimental task employed, this area demonstrated a differentiated activity involving expectation, planning and preparedness in the ball's drop task.O estudo tentou elucidar mecanismos eletrofisiológicos e corticais envolvidos em ações antecipatórias quando os sujeitos testados tiveram que apreender bolas em queda livre; especificamente através de mudanças na potência absoluta na banda alfa da eletrencefalografia quantitativa (EEGq. A amostra foi composta por 23 sujeitos sadios, ambos os sexos, idade entre variando entre 25 e 40 anos, sem comprometimento físico e mental, destros, e não fazer uso de nenhuma substância psicoativa ou psicotrópicos até o momento do estudo. O experimento consistiu de uma tarefa de apreensão de bolas em queda livre. A análise three-way ANOVA demonstrou uma interação entre os fatores momento e posição no córtex parietal posterior (CPP esquerdo (p=0,001. Através da tarefa experimental empregada, esta área demonstrou uma atividade diferenciada envolvendo expectativa, planejamento e prontidão na tarefa de queda de bolas.

  7. Classic and Golli Myelin Basic Protein have distinct developmental trajectories in human visual cortex.

    Science.gov (United States)

    Siu, Caitlin R; Balsor, Justin L; Jones, David G; Murphy, Kathryn M

    2015-01-01

    Traditionally, myelin is viewed as insulation around axons, however, more recent studies have shown it also plays an important role in plasticity, axonal metabolism, and neuroimmune signaling. Myelin is a complex multi-protein structure composed of hundreds of proteins, with Myelin Basic Protein (MBP) being the most studied. MBP has two families: Classic-MBP that is necessary for activity driven compaction of myelin around axons, and Golli-MBP that is found in neurons, oligodendrocytes, and T-cells. Furthermore, Golli-MBP has been called a "molecular link" between the nervous and immune systems. In visual cortex specifically, myelin proteins interact with immune processes to affect experience-dependent plasticity. We studied myelin in human visual cortex using Western blotting to quantify Classic- and Golli-MBP expression in post-mortem tissue samples ranging in age from 20 days to 80 years. We found that Classic- and Golli-MBP have different patterns of change across the lifespan. Classic-MBP gradually increases to 42 years and then declines into aging. Golli-MBP has early developmental changes that are coincident with milestones in visual system sensitive period, and gradually increases into aging. There are three stages in the balance between Classic- and Golli-MBP expression, with Golli-MBP dominating early, then shifting to Classic-MBP, and back to Golli-MBP in aging. Also Golli-MBP has a wave of high inter-individual variability during childhood. These results about cortical MBP expression are timely because they compliment recent advances in MRI techniques that produce high resolution maps of cortical myelin in normal and diseased brain. In addition, the unique pattern of Golli-MBP expression across the lifespan suggests that it supports high levels of neuroimmune interaction in cortical development and in aging.

  8. Modulatory Effects of Attention on Lateral Inhibition in the Human Auditory Cortex.

    Directory of Open Access Journals (Sweden)

    Alva Engell

    Full Text Available Reduced neural processing of a tone is observed when it is presented after a sound whose spectral range closely frames the frequency of the tone. This observation might be explained by the mechanism of lateral inhibition (LI due to inhibitory interneurons in the auditory system. So far, several characteristics of bottom up influences on LI have been identified, while the influence of top-down processes such as directed attention on LI has not been investigated. Hence, the study at hand aims at investigating the modulatory effects of focused attention on LI in the human auditory cortex. In the magnetoencephalograph, we present two types of masking sounds (white noise vs. withe noise passing through a notch filter centered at a specific frequency, followed by a test tone with a frequency corresponding to the center-frequency of the notch filter. Simultaneously, subjects were presented with visual input on a screen. To modulate the focus of attention, subjects were instructed to concentrate either on the auditory input or the visual stimuli. More specific, on one half of the trials, subjects were instructed to detect small deviations in loudness in the masking sounds while on the other half of the trials subjects were asked to detect target stimuli on the screen. The results revealed a reduction in neural activation due to LI, which was larger during auditory compared to visual focused attention. Attentional modulations of LI were observed in two post-N1m time intervals. These findings underline the robustness of reduced neural activation due to LI in the auditory cortex and point towards the important role of attention on the modulation of this mechanism in more evaluative processing stages.

  9. Modulatory Effects of Attention on Lateral Inhibition in the Human Auditory Cortex.

    Science.gov (United States)

    Engell, Alva; Junghöfer, Markus; Stein, Alwina; Lau, Pia; Wunderlich, Robert; Wollbrink, Andreas; Pantev, Christo

    2016-01-01

    Reduced neural processing of a tone is observed when it is presented after a sound whose spectral range closely frames the frequency of the tone. This observation might be explained by the mechanism of lateral inhibition (LI) due to inhibitory interneurons in the auditory system. So far, several characteristics of bottom up influences on LI have been identified, while the influence of top-down processes such as directed attention on LI has not been investigated. Hence, the study at hand aims at investigating the modulatory effects of focused attention on LI in the human auditory cortex. In the magnetoencephalograph, we present two types of masking sounds (white noise vs. withe noise passing through a notch filter centered at a specific frequency), followed by a test tone with a frequency corresponding to the center-frequency of the notch filter. Simultaneously, subjects were presented with visual input on a screen. To modulate the focus of attention, subjects were instructed to concentrate either on the auditory input or the visual stimuli. More specific, on one half of the trials, subjects were instructed to detect small deviations in loudness in the masking sounds while on the other half of the trials subjects were asked to detect target stimuli on the screen. The results revealed a reduction in neural activation due to LI, which was larger during auditory compared to visual focused attention. Attentional modulations of LI were observed in two post-N1m time intervals. These findings underline the robustness of reduced neural activation due to LI in the auditory cortex and point towards the important role of attention on the modulation of this mechanism in more evaluative processing stages.

  10. Conantokin probes of NMDA receptors in normal and Alzheimer disease human cerebral cortex

    International Nuclear Information System (INIS)

    Ragnarsson, L.; Dodd, P.R.; Lewis, R.J.

    2002-01-01

    Full text: The pharmacology of the N-methyl-D-aspartate (NMDA) receptor site was examined in pathologically affected and relatively spared regions of cerebral cortex tissue obtained at autopsy from Alzheimer disease cases and matched controls. The affinity and density of the [ 3 H]MK-801 binding site were delineated along with the enhancement of [ 3 H]MK-801 binding by glutamate and spermine. Sites with distinct pharmacologies were distributed regionally through the cortex. The differences could not be explained by variations in the parameters of [ 3 H]MK-801 binding; rather, the data suggest that the subunit composition of NMDA receptors may be locally variable. Selective differences were also found between controls and Alzheimer disease cases in certain brain regions. The interactions of human NMDA sites with the Ala(7) and Lys(7) derivatives of conantokin-G (Con-G) were also characterized. Ala(7)-con-G showed the higher affinity of the two peptides, and also defined two distinct binding sites in controls. In distinction to the Ala(7) peptide, Lys(7)- con-G showed preferential binding to receptor sites in Alzheimer disease cf. control brain. Modified conantokins are useful for identifying differences in subunit composition of the NMDA receptors between brain areas. They may also have potential as protective agents against over-excitation mediated by specific NMDA receptors, which might contribute to localized brain damage in Alzheimer disease. For further characterization of the pharmacology of different NMDA receptor subunits, a mammalian expression system has been developed for the analysis of their responses to selected ligands, including conantokins. Copyright (2002) Australian Neuroscience Society

  11. Influence of motivation on control hierarchy in the human frontal cortex.

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    Bahlmann, Jörg; Aarts, Esther; D'Esposito, Mark

    2015-02-18

    The frontal cortex mediates cognitive control and motivation to shape human behavior. It is generally observed that medial frontal areas are involved in motivational aspects of behavior, whereas lateral frontal regions are involved in cognitive control. Recent models of cognitive control suggest a rostro-caudal gradient in lateral frontal regions, such that progressively more rostral (anterior) regions process more complex aspects of cognitive control. How motivation influences such a control hierarchy is still under debate. Although some researchers argue that both systems work in parallel, others argue in favor of an interaction between motivation and cognitive control. In the latter case it is yet unclear how motivation would affect the different levels of the control hierarchy. This was investigated in the present functional MRI study applying different levels of cognitive control under different motivational states (low vs high reward anticipation). Three levels of cognitive control were tested by varying rule complexity: stimulus-response mapping (low-level), flexible task updating (mid-level), and sustained cue-task associations (high-level). We found an interaction between levels of cognitive control and motivation in medial and lateral frontal subregions. Specifically, flexible updating (mid-level of control) showed the strongest beneficial effect of reward and only this level exhibited functional coupling between dopamine-rich midbrain regions and the lateral frontal cortex. These findings suggest that motivation differentially affects the levels of a control hierarchy, influencing recruitment of frontal cortical control regions depending on specific task demands. Copyright © 2015 the authors 0270-6474/15/353207-11$15.00/0.

  12. Attention improves encoding of task-relevant features in the human visual cortex

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    Jehee, Janneke F.M.; Brady, Devin K.; Tong, Frank

    2011-01-01

    When spatial attention is directed towards a particular stimulus, increased activity is commonly observed in corresponding locations of the visual cortex. Does this attentional increase in activity indicate improved processing of all features contained within the attended stimulus, or might spatial attention selectively enhance the features relevant to the observer’s task? We used fMRI decoding methods to measure the strength of orientation-selective activity patterns in the human visual cortex while subjects performed either an orientation or contrast discrimination task, involving one of two laterally presented gratings. Greater overall BOLD activation with spatial attention was observed in areas V1-V4 for both tasks. However, multivariate pattern analysis revealed that orientation-selective responses were enhanced by attention only when orientation was the task-relevant feature, and not when the grating’s contrast had to be attended. In a second experiment, observers discriminated the orientation or color of a specific lateral grating. Here, orientation-selective responses were enhanced in both tasks but color-selective responses were enhanced only when color was task-relevant. In both experiments, task-specific enhancement of feature-selective activity was not confined to the attended stimulus location, but instead spread to other locations in the visual field, suggesting the concurrent involvement of a global feature-based attentional mechanism. These results suggest that attention can be remarkably selective in its ability to enhance particular task-relevant features, and further reveal that increases in overall BOLD amplitude are not necessarily accompanied by improved processing of stimulus information. PMID:21632942

  13. Development of Glutamatergic Proteins in Human Visual Cortex across the Lifespan.

    Science.gov (United States)

    Siu, Caitlin R; Beshara, Simon P; Jones, David G; Murphy, Kathryn M

    2017-06-21

    Traditionally, human primary visual cortex (V1) has been thought to mature within the first few years of life, based on anatomical studies of synapse formation, and establishment of intracortical and intercortical connections. Human vision, however, develops well beyond the first few years. Previously, we found prolonged development of some GABAergic proteins in human V1 (Pinto et al., 2010). Yet as >80% of synapses in V1 are excitatory, it remains unanswered whether the majority of synapses regulating experience-dependent plasticity and receptive field properties develop late, like their inhibitory counterparts. To address this question, we used Western blotting of postmortem tissue from human V1 (12 female, 18 male) covering a range of ages. Then we quantified a set of postsynaptic glutamatergic proteins (PSD-95, GluA2, GluN1, GluN2A, GluN2B), calculated indices for functional pairs that are developmentally regulated (GluA2:GluN1; GluN2A:GluN2B), and determined interindividual variability. We found early loss of GluN1, prolonged development of PSD-95 and GluA2 into late childhood, protracted development of GluN2A until ∼40 years, and dramatic loss of GluN2A in aging. The GluA2:GluN1 index switched at ∼1 year, but the GluN2A:GluN2B index continued to shift until ∼40 year before changing back to GluN2B in aging. We also identified young childhood as a stage of heightened interindividual variability. The changes show that human V1 develops gradually through a series of five orchestrated stages, making it likely that V1 participates in visual development and plasticity across the lifespan. SIGNIFICANCE STATEMENT Anatomical structure of human V1 appears to mature early, but vision changes across the lifespan. This discrepancy has fostered two hypotheses: either other aspects of V1 continue changing, or later changes in visual perception depend on extrastriate areas. Previously, we showed that some GABAergic synaptic proteins change across the lifespan, but most

  14. Probing the corticospinal link between the motor cortex and motoneurones: some neglected aspects of human motor cortical function

    DEFF Research Database (Denmark)

    Petersen, Nicolas Caesar; Butler, Jane E.; Taylor, Janet L.

    2010-01-01

    of the discharge of motor units have revealed that the rapidly conducting corticospinal axons (stimulated at higher intensities) contribute to drive motoneurones in normal voluntary contractions. There are also major non-linearities generated at a spinal level in the relation between corticospinal output...... magnetic stimulation of the human motor cortex have highlighted the capacity of the cortex to modify its apparent excitability in response to altered afferent inputs, training and various pathologies. Studies using cortical stimulation at 'very low' intensities which elicit only short-latency suppression...

  15. Aging Affects Adaptation to Sound-Level Statistics in Human Auditory Cortex.

    Science.gov (United States)

    Herrmann, Björn; Maess, Burkhard; Johnsrude, Ingrid S

    2018-02-21

    Optimal perception requires efficient and adaptive neural processing of sensory input. Neurons in nonhuman mammals adapt to the statistical properties of acoustic feature distributions such that they become sensitive to sounds that are most likely to occur in the environment. However, whether human auditory responses adapt to stimulus statistical distributions and how aging affects adaptation to stimulus statistics is unknown. We used MEG to study how exposure to different distributions of sound levels affects adaptation in auditory cortex of younger (mean: 25 years; n = 19) and older (mean: 64 years; n = 20) adults (male and female). Participants passively listened to two sound-level distributions with different modes (either 15 or 45 dB sensation level). In a control block with long interstimulus intervals, allowing neural populations to recover from adaptation, neural response magnitudes were similar between younger and older adults. Critically, both age groups demonstrated adaptation to sound-level stimulus statistics, but adaptation was altered for older compared with younger people: in the older group, neural responses continued to be sensitive to sound level under conditions in which responses were fully adapted in the younger group. The lack of full adaptation to the statistics of the sensory environment may be a physiological mechanism underlying the known difficulty that older adults have with filtering out irrelevant sensory information. SIGNIFICANCE STATEMENT Behavior requires efficient processing of acoustic stimulation. Animal work suggests that neurons accomplish efficient processing by adjusting their response sensitivity depending on statistical properties of the acoustic environment. Little is known about the extent to which this adaptation to stimulus statistics generalizes to humans, particularly to older humans. We used MEG to investigate how aging influences adaptation to sound-level statistics. Listeners were presented with sounds drawn from

  16. Reduced recruitment of orbitofrontal cortex to human social chemosensory cues in social anxiety.

    Science.gov (United States)

    Zhou, Wen; Hou, Ping; Zhou, Yuxiang; Chen, Denise

    2011-04-01

    Social anxiety refers to the prevalent and debilitating experience of fear and anxiety of being scrutinized in social situations. It originates from both learned (e.g. adverse social conditioning) and innate (e.g. shyness) factors. Research on social anxiety has traditionally focused on negative emotions induced by visual and auditory social cues in socially anxious clinical populations, and posits a dysfunctional orbitofrontal-amygdala circuit as a primary etiological mechanism. Yet as a trait, social anxiety is independent of one's specific emotional state. Here we probe the neural substrate of intrinsic social anxiety by employing a unique type of social stimuli, airborne human social chemosensory cues that are inherently social, ubiquitously present, and yet operating below verbal awareness. We show that the adopted social chemosensory cues were not perceived to be human-related, did not differentially bias self-report of anxiety or autonomic nervous system responses, yet individuals with elevated social anxiety demonstrated a reduced recruitment of the orbitofrontal cortex to social chemosensory cues. No reciprocal activity in the amygdala was observed. Our findings point to an intrinsic neural substrate underlying social anxiety that is not associated with prior adverse social conditioning, thereby providing the first neural evidence for the inherent social aspect of this enigmatic phenomenon. Copyright © 2010 Elsevier Inc. All rights reserved.

  17. Activations of human auditory cortex to phonemic and nonphonemic vowels during discrimination and memory tasks.

    Science.gov (United States)

    Harinen, Kirsi; Rinne, Teemu

    2013-08-15

    We used fMRI to investigate activations within human auditory cortex (AC) to vowels during vowel discrimination, vowel (categorical n-back) memory, and visual tasks. Based on our previous studies, we hypothesized that the vowel discrimination task would be associated with increased activations in the anterior superior temporal gyrus (STG), while the vowel memory task would enhance activations in the posterior STG and inferior parietal lobule (IPL). In particular, we tested the hypothesis that activations in the IPL during vowel memory tasks are associated with categorical processing. Namely, activations due to categorical processing should be higher during tasks performed on nonphonemic (hard to categorize) than on phonemic (easy to categorize) vowels. As expected, we found distinct activation patterns during vowel discrimination and vowel memory tasks. Further, these task-dependent activations were different during tasks performed on phonemic or nonphonemic vowels. However, activations in the IPL associated with the vowel memory task were not stronger during nonphonemic than phonemic vowel blocks. Together these results demonstrate that activations in human AC to vowels depend on both the requirements of the behavioral task and the phonemic status of the vowels. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Spike-timing-dependent plasticity in the human dorso-lateral prefrontal cortex.

    Science.gov (United States)

    Casula, Elias Paolo; Pellicciari, Maria Concetta; Picazio, Silvia; Caltagirone, Carlo; Koch, Giacomo

    2016-12-01

    Changes in the synaptic strength of neural connections are induced by repeated coupling of activity of interconnected neurons with precise timing, a phenomenon known as spike-timing-dependent plasticity (STDP). It is debated if this mechanism exists in large-scale cortical networks in humans. We combined transcranial magnetic stimulation (TMS) with concurrent electroencephalography (EEG) to directly investigate the effects of two paired associative stimulation (PAS) protocols (fronto-parietal and parieto-frontal) of pre and post-synaptic inputs within the human fronto-parietal network. We found evidence that the dorsolateral prefrontal cortex (DLPFC) has the potential to form robust STDP. Long-term potentiation/depression of TMS-evoked cortical activity is prompted after that DLPFC stimulation is followed/preceded by posterior parietal stimulation. Such bidirectional changes are paralleled by sustained increase/decrease of high-frequency oscillatory activity, likely reflecting STDP responsivity. The current findings could be important to drive plasticity of damaged cortical circuits in patients with cognitive or psychiatric disorders. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Controllability modulates the anticipatory response in the human ventromedial prefrontal cortex

    Directory of Open Access Journals (Sweden)

    Deborah Lucille Kerr

    2012-12-01

    Full Text Available Research has consistently shown that control is critical to psychological functioning, with perceived lack of control considered to play a crucial role in the manifestation of symptoms in psychiatric disorders. In a model of behavioral control based on nonhuman animal work, Maier and colleagues posited that the presence of control activates areas of the ventromedial prefrontal cortex (vmPFC, which in turn inhibit the normative stress response in the dorsal raphe nucleus and amygdala. To test Maier’s model in humans, we investigated the effects of control over potent aversive stimuli by presenting video clips of snakes to 21 snake phobics who were otherwise healthy with no comorbid psychopathologies. Based on prior research documenting that disrupted neural processing during the anticipation of adverse events can be influenced by different forms of cognitive processing such as perceptions of control, analyses focused on the anticipatory activity preceding the videos. We found that phobics exhibited greater vmPFC activity during the anticipation of snake videos when they had control over whether the videos were presented as compared to when they had no control over the presentation of the videos. In addition, observed functional connectivity between the vmPFC and the amygdala is consistent with previous work documenting vmPFC inhibition of the amygdala. Our results provide evidence to support the extension of Maier’s model of behavioral control to include anticipatory function in humans.

  20. Cellular and synaptic localization of EAAT2a in human cerebral cortex

    Directory of Open Access Journals (Sweden)

    Marcello eMelone

    2011-01-01

    Full Text Available We used light and electron microscopic immunocytochemical techniques to analyze the distribution, cellular and synaptic localization of EAAT2, the main glutamate transporter, in normal human neocortex. EAAT2a immunoreactivity was in all layers and consisted of small neuropilar puncta and rare cells. In white matter EAAT2a+ cells were numerous. Electron microscopic studies showed that in gray matter ∼77% of immunoreactive elements were astrocytic processes, ∼14% axon terminals, ∼2.8% dendrites, whereas ∼5% were unidentifiable. In white matter, ∼81% were astrocytic processes, ∼17% were myelinated axons and ∼2.0% were unidentified. EAAT2a immunoreactivity was never in microglial cells and oligodendrocytes. Pre-embedding electron microscopy showed that ∼67% of EAAT2a expressed at (or in the vicinity of asymmetric synapses was in astrocytes, ∼17% in axon terminals, while ∼13% was both in astrocytes and in axons. Post-embeddeding electron microscopy studies showed that in astrocytic processes contacting asymmetric synapses and in axon terminals, gold particle density was ∼25.1 and ∼2.8 particles/µm2, respectively, and was concentrated in a membrane region extending for ∼300 nm from the active zone edge. Besides representing the first detailed description of EAAT2a in human cerebral cortex, these findings may contribute to understanding its role in the pathophysiology of neuropsychiatric diseases.

  1. Frequency-specific modulation of population-level frequency tuning in human auditory cortex

    Directory of Open Access Journals (Sweden)

    Roberts Larry E

    2009-01-01

    Full Text Available Abstract Background Under natural circumstances, attention plays an important role in extracting relevant auditory signals from simultaneously present, irrelevant noises. Excitatory and inhibitory neural activity, enhanced by attentional processes, seems to sharpen frequency tuning, contributing to improved auditory performance especially in noisy environments. In the present study, we investigated auditory magnetic fields in humans that were evoked by pure tones embedded in band-eliminated noises during two different stimulus sequencing conditions (constant vs. random under auditory focused attention by means of magnetoencephalography (MEG. Results In total, we used identical auditory stimuli between conditions, but presented them in a different order, thereby manipulating the neural processing and the auditory performance of the listeners. Constant stimulus sequencing blocks were characterized by the simultaneous presentation of pure tones of identical frequency with band-eliminated noises, whereas random sequencing blocks were characterized by the simultaneous presentation of pure tones of random frequencies and band-eliminated noises. We demonstrated that auditory evoked neural responses were larger in the constant sequencing compared to the random sequencing condition, particularly when the simultaneously presented noises contained narrow stop-bands. Conclusion The present study confirmed that population-level frequency tuning in human auditory cortex can be sharpened in a frequency-specific manner. This frequency-specific sharpening may contribute to improved auditory performance during detection and processing of relevant sound inputs characterized by specific frequency distributions in noisy environments.

  2. Improving Sensorimotor Function Using Stochastic Vestibular Stimulation

    Science.gov (United States)

    Galvan, R. C.; Clark, T. K.; Merfeld, D. M.; Bloomberg, J. J.; Mulavara, A. P.; Oman, C. M.

    2014-01-01

    measurement units placed on the upper and lower torso of the subjects. Additionally, each individual’s threshold for illusory motion perception of suprasensory electrical vestibular stimulation is measured multiple times within and across days to better understand how multiple SVS test methods compare. The second study aims to demonstrate stochastic resonance in the vestibular system using a perception based motion recognition task. This task measures an individual’s velocity threshold of motion recognition using a 6-degree of freedom Stewart platform and a 3-down/1-up staircase procedure. For this study, thresholds are determined using 150 trials in the upright, head-centered roll tilt motion direction at a 0.2 Hz frequency. We aim to demonstrate the characteristic bell shaped curve associated with stochastic resonance with each subject’s motion recognition thresholds at varying SVS levels ranging from 0 to 1500 micro A. The curve includes the individual’s baseline threshold with no SVS, optimal or minimal threshold at some mid-level of SVS, and finally degraded or increased threshold at a high SVS level. An additional aim is to formally retest each subject at his or her individual optimal SVS level on a different day than the original testing for additional validity. The overall purpose of this research is to further quantify the effects of SVS on various sensorimotor tasks and investigate the practical implications of its use in the context of human space flight so that it may be implemented in the future as a component of a comprehensive countermeasure plan for adaptation to G-transitions.

  3. Probabilistic Tractography Recovers a Rostrocaudal Trajectory of Connectivity Variability in the Human Insular Cortex

    Science.gov (United States)

    Cerliani, Leonardo; Thomas, Rajat M; Jbabdi, Saad; Siero, Jeroen CW; Nanetti, Luca; Crippa, Alessandro; Gazzola, Valeria; D'Arceuil, Helen; Keysers, Christian

    2012-01-01

    The insular cortex of macaques has a wide spectrum of anatomical connections whose distribution is related to its heterogeneous cytoarchitecture. Although there is evidence of a similar cytoarchitectural arrangement in humans, the anatomical connectivity of the insula in the human brain has not yet been investigated in vivo. In the present work, we used in vivo probabilistic white-matter tractography and Laplacian eigenmaps (LE) to study the variation of connectivity patterns across insular territories in humans. In each subject and hemisphere, we recovered a rostrocaudal trajectory of connectivity variation ranging from the anterior dorsal and ventral insula to the dorsal caudal part of the long insular gyri. LE suggested that regional transitions among tractography patterns in the insula occur more gradually than in other brain regions. In particular, the change in tractography patterns was more gradual in the insula than in the medial premotor region, where a sharp transition between different tractography patterns was found. The recovered trajectory of connectivity variation in the insula suggests a relation between connectivity and cytoarchitecture in humans resembling that previously found in macaques: tractography seeds from the anterior insula were mainly found in limbic and paralimbic regions and in anterior parts of the inferior frontal gyrus, while seeds from caudal insular territories mostly reached parietal and posterior temporal cortices. Regions in the putative dysgranular insula displayed more heterogeneous connectivity patterns, with regional differences related to the proximity with either putative granular or agranular regions. Hum Brain Mapp 33:2005–2034, 2012. © 2011 Wiley Periodicals, Inc. PMID:21761507

  4. Learning and Recognition of a Non-conscious Sequence of Events in Human Primary Visual Cortex.

    Science.gov (United States)

    Rosenthal, Clive R; Andrews, Samantha K; Antoniades, Chrystalina A; Kennard, Christopher; Soto, David

    2016-03-21

    Human primary visual cortex (V1) has long been associated with learning simple low-level visual discriminations [1] and is classically considered outside of neural systems that support high-level cognitive behavior in contexts that differ from the original conditions of learning, such as recognition memory [2, 3]. Here, we used a novel fMRI-based dichoptic masking protocol-designed to induce activity in V1, without modulation from visual awareness-to test whether human V1 is implicated in human observers rapidly learning and then later (15-20 min) recognizing a non-conscious and complex (second-order) visuospatial sequence. Learning was associated with a change in V1 activity, as part of a temporo-occipital and basal ganglia network, which is at variance with the cortico-cerebellar network identified in prior studies of "implicit" sequence learning that involved motor responses and visible stimuli (e.g., [4]). Recognition memory was associated with V1 activity, as part of a temporo-occipital network involving the hippocampus, under conditions that were not imputable to mechanisms associated with conscious retrieval. Notably, the V1 responses during learning and recognition separately predicted non-conscious recognition memory, and functional coupling between V1 and the hippocampus was enhanced for old retrieval cues. The results provide a basis for novel hypotheses about the signals that can drive recognition memory, because these data (1) identify human V1 with a memory network that can code complex associative serial visuospatial information and support later non-conscious recognition memory-guided behavior (cf. [5]) and (2) align with mouse models of experience-dependent V1 plasticity in learning and memory [6]. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Human left ventral premotor cortex mediates matching of hand posture to object use.

    Directory of Open Access Journals (Sweden)

    Guy Vingerhoets

    Full Text Available Visuomotor transformations for grasping have been associated with a fronto-parietal network in the monkey brain. The human homologue of the parietal monkey region (AIP has been identified as the anterior part of the intraparietal sulcus (aIPS, whereas the putative human equivalent of the monkey frontal region (F5 is located in the ventral part of the premotor cortex (vPMC. Results from animal studies suggest that monkey F5 is involved in the selection of appropriate hand postures relative to the constraints of the task. In humans, the functional roles of aIPS and vPMC appear to be more complex and the relative contribution of each region to grasp selection remains uncertain. The present study aimed to identify modulation in brain areas sensitive to the difficulty level of tool object - hand posture matching. Seventeen healthy right handed participants underwent fMRI while observing pictures of familiar tool objects followed by pictures of hand postures. The task was to decide whether the hand posture matched the functional use of the previously shown object. Conditions were manipulated for level of difficulty. Compared to a picture matching control task, the tool object - hand posture matching conditions conjointly showed increased modulation in several left hemispheric regions of the superior and inferior parietal lobules (including aIPS, the middle occipital gyrus, and the inferior temporal gyrus. Comparison of hard versus easy conditions selectively modulated the left inferior frontal gyrus with peak activity located in its opercular part (Brodmann area (BA 44. We suggest that in the human brain, vPMC/BA44 is involved in the matching of hand posture configurations in accordance with visual and functional demands.

  6. Canine and human visual cortex intact and responsive despite early retinal blindness from RPE65 mutation.

    Directory of Open Access Journals (Sweden)

    Geoffrey K Aguirre

    2007-06-01

    Full Text Available RPE65 is an essential molecule in the retinoid-visual cycle, and RPE65 gene mutations cause the congenital human blindness known as Leber congenital amaurosis (LCA. Somatic gene therapy delivered to the retina of blind dogs with an RPE65 mutation dramatically restores retinal physiology and has sparked international interest in human treatment trials for this incurable disease. An unanswered question is how the visual cortex responds after prolonged sensory deprivation from retinal dysfunction. We therefore studied the cortex of RPE65-mutant dogs before and after retinal gene therapy. Then, we inquired whether there is visual pathway integrity and responsivity in adult humans with LCA due to RPE65 mutations (RPE65-LCA.RPE65-mutant dogs were studied with fMRI. Prior to therapy, retinal and subcortical responses to light were markedly diminished, and there were minimal cortical responses within the primary visual areas of the lateral gyrus (activation amplitude mean +/- standard deviation [SD] = 0.07% +/- 0.06% and volume = 1.3 +/- 0.6 cm(3. Following therapy, retinal and subcortical response restoration was accompanied by increased amplitude (0.18% +/- 0.06% and volume (8.2 +/- 0.8 cm(3 of activation within the lateral gyrus (p < 0.005 for both. Cortical recovery occurred rapidly (within a month of treatment and was persistent (as long as 2.5 y after treatment. Recovery was present even when treatment was provided as late as 1-4 y of age. Human RPE65-LCA patients (ages 18-23 y were studied with structural magnetic resonance imaging. Optic nerve diameter (3.2 +/- 0.5 mm was within the normal range (3.2 +/- 0.3 mm, and occipital cortical white matter density as judged by voxel-based morphometry was slightly but significantly altered (1.3 SD below control average, p = 0.005. Functional magnetic resonance imaging in human RPE65-LCA patients revealed cortical responses with a markedly diminished activation volume (8.8 +/- 1.2 cm(3 compared to controls

  7. Neurochemical Characterization of PSA-NCAM+ Cells in the Human Brain and Phenotypic Quantification in Alzheimer's Disease Entorhinal Cortex.

    Science.gov (United States)

    Murray, Helen C; Swanson, Molly E V; Dieriks, B Victor; Turner, Clinton; Faull, Richard L M; Curtis, Maurice A

    2018-02-21

    Polysialylated neural cell adhesion molecule (PSA-NCAM) is widely expressed in the adult human brain and facilitates structural remodeling of cells through steric inhibition of intercellular NCAM adhesion. We previously showed that PSA-NCAM immunoreactivity is decreased in the entorhinal cortex in Alzheimer's disease (AD). Based on available evidence, we hypothesized that a loss of PSA-NCAM + interneurons may underlie this reduction. PSA-NCAM expression by interneurons has previously been described in the human medial prefrontal cortex. Here we used postmortem human brain tissue to provide further evidence of PSA-NCAM + interneurons throughout the human hippocampal formation and additional cortical regions. Furthermore, PSA-NCAM + cell populations were assessed in the entorhinal cortex of normal and AD cases using fluorescent double labeling and manual cell counting. We found a significant decrease in the number of PSA-NCAM + cells per mm 2 in layer II and V of the entorhinal cortex, supporting our previous description of reduced PSA-NCAM immunoreactivity. Additionally, we found a significant decrease in the proportion of PSA-NCAM + cells that co-labeled with NeuN and parvalbumin, but no change in the proportion that co-labeled with calbindin or calretinin. These results demonstrate that PSA-NCAM is expressed by a variety of interneuron populations throughout the brain. Furthermore, that loss of PSA-NCAM expression by NeuN + cells predominantly contributes to the reduced PSA-NCAM immunoreactivity in the AD entorhinal cortex. Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.

  8. 3-D Cytoarchitectonic parcellation of human orbitofrontal cortex Correlation with postmortem MRI

    NARCIS (Netherlands)

    Uylings, H.B.M.; Sanz-Arigita, E.J.; Vos, K.; Pool, C.W.; Evers, P.; Rajkowska, G.

    2010-01-01

    The orbitofrontal cortex (OFC) is located on the basal surface of the frontal lobe and is distinguished by its unique anatomical and functional features. Clinical and postmortem studies suggest the involvement of the orbitofrontal cortex in psychiatric disorders. However, the exact parcellation of

  9. An anatomical substrate for integration among functional networks in human cortex.

    Science.gov (United States)

    van den Heuvel, Martijn P; Sporns, Olaf

    2013-09-04

    The human brain shows several characteristics of an efficient communication network architecture, including short communication paths and the existence of modules interlinked by a small set of highly connected regions. Studies of structural networks comprising macroscopic white matter projections have shown that these putative hubs are densely interconnected, giving rise to a spatially distributed and topologically central collective called the "rich club." In parallel, studies of intrinsic brain activity have consistently revealed distinct functional communities or resting-state networks (RSNs), indicative of specialized processing and segregation of neuronal information. However, the pattern of structural connectivity interconnecting these functional RSNs and how such inter-RSN structural connections might bring about functional integration between RSNs remain largely unknown. Combining high-resolution diffusion weighted imaging with resting-state fMRI, we present novel evidence suggesting that the rich club structure plays a central role in cross-linking macroscopic RSNs of the human brain. Rich club hub nodes were present in all functional networks, accounted for a large proportion of "connector nodes," and were found to coincide with regions in which multiple networks overlap. In addition, a large proportion of all inter-RSN connections were found to involve rich club nodes, and these connections participated in a disproportionate number of communication paths linking nodes in different RSNs. Our findings suggest that the brain's rich club serves as a macroscopic anatomical substrate to cross-link functional networks and thus plays an important role in the integration of information between segregated functional domains of the human cortex.

  10. Selective increases of AMPA, NMDA and kainate receptor subunit mRNAs in the hippocampus and orbitofrontal cortex but not in prefrontal cortex of human alcoholics

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    Zhe eJin

    2014-01-01

    Full Text Available Glutamate is the main excitatory transmitter in the human brain. Drugs that affect the glutamatergic signaling will alter neuronal excitability. Ethanol inhibits glutamate receptors. We examined the expression level of glutamate receptor subunit mRNAs in human post-mortem samples from alcoholics and compared the results to brain samples from control subjects. RNA from hippocampal dentate gyrus (HP-DG, orbitofrontal cortex (OFC, and dorso-lateral prefrontal cortex (DL-PFC samples from 21 controls and 19 individuals with chronic alcohol dependence were included in the study. Total RNA was assayed using quantitative RT-PCR. Out of the 16 glutamate receptor subunits, mRNAs encoding two AMPA (2-amino-3-(3-hydroxy-5-methyl-isoxazol-4-ylpropanoic acid receptor subunits GluA2 and GluA3; three kainate receptor subunits GluK2, GluK3 and GluK5 and five NMDA (N-methyl-D-aspartate receptor subunits GluN1, GluN2A, GluN2C, GluN2D and GluN3A were significantly increased in the HP-DG region in alcoholics. In the OFC, mRNA encoding the NMDA receptor subunit GluN3A was increased, whereas in the DL-PFC, no differences in mRNA levels were observed. Our laboratory has previously shown that the expression of genes encoding inhibitory GABA-A receptors is altered in the HP-DG and OFC of alcoholics (Jin et al., 2011. Whether the changes in one neurotransmitter system drives changes in the other or if they change independently is currently not known. The results demonstrate that excessive long-term alcohol consumption is associated with altered expression of genes encoding glutamate receptors in a brain region-specific manner. It is an intriguing possibility that genetic predisposition to alcoholism may contribute to these gene expression changes.

  11. Analysis of neural activity in human motor cortex -- Towards brain machine interface system

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    Secundo, Lavi

    The discovery of directional tuned neurons in the primary motor cortex has advanced motor research in several domains. For instance, in the area of brain machine interface (BMI), researchers have exploited the robust characteristic of tuned motor neurons to allow monkeys to learn control of various machines. In the first chapter of this work we examine whether this phenomena can be observed using the less invasive method of recording electrocorticographic signals (ECoG) from the surface of a human's brain. Our findings reveal that individual ECoG channels contain complex movement information about the neuronal population. While some ECoG channels are tuned to hand movement direction (direction specific channels), others are associated to movement but do not contain information regarding movement direction (non-direction specific channels). More specifically, directionality can vary temporally and by frequency within one channel. In addition, a handful of channels contain no significant information regarding movement at all. These findings strongly suggest that directional and non-directional regions of cortex can be identified with ECoG and provide solutions to decoding movement at the signal resolution provided by ECoG. In the second chapter we examine the influence of movement context on movement reconstruction accuracy. We recorded neuronal signals recorded from electro-corticography (ECoG) during performance of cued- and self-initiated movements. ECoG signals were used to train a reconstruction algorithm to reconstruct continuous hand movement. We found that both cued- and self-initiated movements could be reconstructed with similar accuracy from the ECoG data. However, while an algorithm trained on the cued task could reconstruct performance on a subsequent cued trial, it failed to reconstruct self-initiated arm movement. The same task-specificity was observed when the algorithm was trained with self-initiated movement data and tested on the cued task. Thus

  12. Sensorimotor integration in chronic stroke: Baseline differences and response to sensory training.

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    Brown, Katlyn E; Neva, Jason L; Feldman, Samantha J; Staines, W Richard; Boyd, Lara A

    2018-01-01

    The integration of somatosensory information from the environment into the motor cortex to inform movement is essential for motor function. As motor deficits commonly persist into the chronic phase of stroke recovery, it is important to understand potential contributing factors to these deficits, as well as their relationship with motor function. To date the impact of chronic stroke on sensorimotor integration has not been thoroughly investigated. The current study aimed to comprehensively examine the influence of chronic stroke on sensorimotor integration, and determine whether sensorimotor integration can be modified with an intervention. Further, it determined the relationship between neurophysiological measures of sensorimotor integration and motor deficits post-stroke. Fourteen individuals with chronic stroke and twelve older healthy controls participated. Motor impairment and function were quantified in individuals with chronic stroke. Baseline neurophysiology was assessed using nerve-based measures (short- and long-latency afferent inhibition, afferent facilitation) and vibration-based measures of sensorimotor integration, which paired vibration with single and paired-pulse TMS techniques. Neurophysiological assessment was performed before and after a vibration-based sensory training paradigm to assess changes within these circuits. Vibration-based, but not nerve-based measures of sensorimotor integration were different in individuals with chronic stroke, as compared to older healthy controls, suggesting that stroke differentially impacts integration of specific types of somatosensory information. Sensorimotor integration was behaviourally relevant in that it related to both motor function and impairment post-stroke. Finally, sensory training modulated sensorimotor integration in individuals with chronic stroke and controls. Sensorimotor integration is differentially impacted by chronic stroke based on the type of afferent feedback. However, both nerve

  13. Activity in human visual and parietal cortex reveals object-based attention in working memory.

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    Peters, Benjamin; Kaiser, Jochen; Rahm, Benjamin; Bledowski, Christoph

    2015-02-25

    Visual attention enables observers to select behaviorally relevant information based on spatial locations, features, or objects. Attentional selection is not limited to physically present visual information, but can also operate on internal representations maintained in working memory (WM) in service of higher-order cognition. However, only little is known about whether attention to WM contents follows the same principles as attention to sensory stimuli. To address this question, we investigated in humans whether the typically observed effects of object-based attention in perception are also evident for object-based attentional selection of internal object representations in WM. In full accordance with effects in visual perception, the key behavioral and neuronal characteristics of object-based attention were observed in WM. Specifically, we found that reaction times were shorter when shifting attention to memory positions located on the currently attended object compared with equidistant positions on a different object. Furthermore, functional magnetic resonance imaging and multivariate pattern analysis of visuotopic activity in visual (areas V1-V4) and parietal cortex revealed that directing attention to one position of an object held in WM also enhanced brain activation for other positions on the same object, suggesting that attentional selection in WM activates the entire object. This study demonstrated that all characteristic features of object-based attention are present in WM and thus follows the same principles as in perception. Copyright © 2015 the authors 0270-6474/15/353360-10$15.00/0.

  14. Segregated encoding of reward-identity and stimulus-reward associations in human orbitofrontal cortex.

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    Klein-Flügge, Miriam Cornelia; Barron, Helen Catharine; Brodersen, Kay Henning; Dolan, Raymond J; Behrens, Timothy Edward John

    2013-02-13

    A dominant focus in studies of learning and decision-making is the neural coding of scalar reward value. This emphasis ignores the fact that choices are strongly shaped by a rich representation of potential rewards. Here, using fMRI adaptation, we demonstrate that responses in the human orbitofrontal cortex (OFC) encode a representation of the specific type of food reward predicted by a visual cue. By controlling for value across rewards and by linking each reward with two distinct stimuli, we could test for representations of reward-identity that were independent of associative information. Our results show reward-identity representations in a medial-caudal region of OFC, independent of the associated predictive stimulus. This contrasts with a more rostro-lateral OFC region encoding reward-identity representations tied to the predicate stimulus. This demonstration of adaptation in OFC to reward specific representations opens an avenue for investigation of more complex decision mechanisms that are not immediately accessible in standard analyses, which focus on correlates of average activity.

  15. GABAergic modulation of DC stimulation-induced motor cortex excitability shifts in humans.

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    Nitsche, Michael A; Liebetanz, David; Schlitterlau, Anett; Henschke, Undine; Fricke, Kristina; Frommann, Kai; Lang, Nicolas; Henning, Stefan; Paulus, Walter; Tergau, Frithjof

    2004-05-01

    Weak transcranial DC stimulation (tDCS) of the human motor cortex results in excitability shifts during and after the end of stimulation, which are most probably localized intracortically. Anodal stimulation enhances excitability, whereas cathodal stimulation reduces it. Although the after-effects of tDCS are NMDA receptor-dependent, nothing is known about the involvement of additional receptors. Here we show that pharmacological strengthening of GABAergic inhibition modulates selectively the after-effects elicited by anodal tDCS. Administration of the GABA(A) receptor agonist lorazepam resulted in a delayed, but then enhanced and prolonged anodal tDCS-induced excitability elevation. The initial absence of an excitability enhancement under lorazepam is most probably caused by a loss of the anodal tDCS-generated intracortical diminution of inhibition and enhancement of facilitation, which occurs without pharmacological intervention. The reasons for the late-occurring excitability enhancement remain unclear. Because intracortical inhibition and facilitation are not changed in this phase compared with pre-tDCS values, excitability changes originating from remote cortical or subcortical areas could be involved.

  16. Neurochemical responses to chromatic and achromatic stimuli in the human visual cortex.

    Science.gov (United States)

    Bednařík, Petr; Tkáč, Ivan; Giove, Federico; Eberly, Lynn E; Deelchand, Dinesh K; Barreto, Felipe R; Mangia, Silvia

    2018-02-01

    In the present study, we aimed at determining the metabolic responses of the human visual cortex during the presentation of chromatic and achromatic stimuli, known to preferentially activate two separate clusters of neuronal populations (called "blobs" and "interblobs") with distinct sensitivity to color or luminance features. Since blobs and interblobs have different cytochrome-oxidase (COX) content and micro-vascularization level (i.e., different capacities for glucose oxidation), different functional metabolic responses during chromatic vs. achromatic stimuli may be expected. The stimuli were optimized to evoke a similar load of neuronal activation as measured by the bold oxygenation level dependent (BOLD) contrast. Metabolic responses were assessed using functional 1 H MRS at 7 T in 12 subjects. During both chromatic and achromatic stimuli, we observed the typical increases in glutamate and lactate concentration, and decreases in aspartate and glucose concentration, that are indicative of increased glucose oxidation. However, within the detection sensitivity limits, we did not observe any difference between metabolic responses elicited by chromatic and achromatic stimuli. We conclude that the higher energy demands of activated blobs and interblobs are supported by similar increases in oxidative metabolism despite the different capacities of these neuronal populations.

  17. An unavoidable modulation? Sensory attention and human primary motor cortex excitability.

    Science.gov (United States)

    Ruge, Diane; Muggleton, Neil; Hoad, Damon; Caronni, Antonio; Rothwell, John C

    2014-09-01

    The link between basic physiology and its modulation by cognitive states, such as attention, is poorly understood. A significant association becomes apparent when patients with movement disorders describe experiences with changing their attention focus and the fundamental effect that this has on their motor symptoms. Moreover, frequently used mental strategies for treating such patients, e.g. with task-specific dystonia, widely lack laboratory-based knowledge about physiological mechanisms. In this largely unexplored field, we looked at how the locus of attention, when it changed between internal (locus hand) and external (visual target), influenced excitability in the primary motor cortex (M1) in healthy humans. Intriguingly, both internal and external attention had the capacity to change M1 excitability. Both led to a reduced stimulation-induced GABA-related inhibition and a change in motor evoked potential size, i.e. an overall increased M1 excitability. These previously unreported findings indicated: (i) that cognitive state differentially interacted with M1 physiology, (ii) that our view of distraction (attention locus shifted towards external or distant location), which is used as a prevention or management strategy for use-dependent motor disorders, is too simple and currently unsupported for clinical application, and (iii) the physiological state reached through attention modulation represents an alternative explanation for frequently reported electrophysiology findings in neuropsychiatric disorders, such as an aberrant inhibition. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  18. Probing changes in corticospinal excitability following theta burst stimulation of the human primary motor cortex.

    Science.gov (United States)

    Goldsworthy, Mitchell R; Vallence, Ann-Maree; Hodyl, Nicolette A; Semmler, John G; Pitcher, Julia B; Ridding, Michael C

    2016-01-01

    To determine whether the intensity of transcranial magnetic stimulation (TMS) used to probe changes in corticospinal excitability influences the measured plasticity response to theta burst stimulation (TBS) of the human primary motor cortex. Motor evoked potential (MEP) input/output (I/O) curves were recorded before and following continuous TBS (cTBS) (Experiment 1; n=18) and intermittent TBS (iTBS) (Experiment 2; n=18). The magnitude and consistency of MEP depression induced by cTBS was greatest when probed using stimulus intensities at or above 150% of resting motor threshold (RMT). In contrast, facilitation of MEPs following iTBS was strongest and most consistent at 110% of RMT. The plasticity response to both cTBS and iTBS is influenced by the stimulus intensity used to probe the induced changes in corticospinal excitability. The results highlight the importance of the test stimulus intensity used to assess TBS-induced changes in corticospinal excitability when interpreting neuroplasticity data, and suggest that a number of test intensities may be required to reliably probe the plasticity response. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  19. Neural Determinants of Task Performance during Feature-Based Attention in Human Cortex

    Science.gov (United States)

    Gong, Mengyuan

    2018-01-01

    Abstract Studies of feature-based attention have associated activity in a dorsal frontoparietal network with putative attentional priority signals. Yet, how this neural activity mediates attentional selection and whether it guides behavior are fundamental questions that require investigation. We reasoned that endogenous fluctuations in the quality of attentional priority should influence task performance. Human subjects detected a speed increment while viewing clockwise (CW) or counterclockwise (CCW) motion (baseline task) or while attending to either direction amid distracters (attention task). In an fMRI experiment, direction-specific neural pattern similarity between the baseline task and the attention task revealed a higher level of similarity for correct than incorrect trials in frontoparietal regions. Using transcranial magnetic stimulation (TMS), we disrupted posterior parietal cortex (PPC) and found a selective deficit in the attention task, but not in the baseline task, demonstrating the necessity of this cortical area during feature-based attention. These results reveal that frontoparietal areas maintain attentional priority that facilitates successful behavioral selection. PMID:29497703

  20. Pupil size directly modulates the feedforward response in human primary visual cortex independently of attention.

    Science.gov (United States)

    Bombeke, Klaas; Duthoo, Wout; Mueller, Sven C; Hopf, Jens-Max; Boehler, C Nico

    2016-02-15

    Controversy revolves around the question of whether psychological factors like attention and emotion can influence the initial feedforward response in primary visual cortex (V1). Although traditionally, the electrophysiological correlate of this response in humans (the C1 component) has been found to be unaltered by psychological influences, a number of recent studies have described attentional and emotional modulations. Yet, research into psychological effects on the feedforward V1 response has neglected possible direct contributions of concomitant pupil-size modulations, which are known to also occur under various conditions of attentional load and emotional state. Here we tested the hypothesis that such pupil-size differences themselves directly affect the feedforward V1 response. We report data from two complementary experiments, in which we used procedures that modulate pupil size without differences in attentional load or emotion while simultaneously recording pupil-size and EEG data. Our results confirm that pupil size indeed directly influences the feedforward V1 response, showing an inverse relationship between pupil size and early V1 activity. While it is unclear in how far this effect represents a functionally-relevant adaptation, it identifies pupil-size differences as an important modulating factor of the feedforward response of V1 and could hence represent a confounding variable in research investigating the neural influence of psychological factors on early visual processing. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Countermeasures to Enhance Sensorimotor Adaptability

    Science.gov (United States)

    Bloomberg, J. J.; Peters, B. T.; Mulavara, A. P.; Brady, R. A.; Batson, C. C.; Miller, C. A.; Cohen, H. S.

    2011-01-01

    During exploration-class missions, sensorimotor disturbances may lead to disruption in the ability to ambulate and perform functional tasks during the initial introduction to a novel gravitational environment following a landing on a planetary surface. The goal of our current project is to develop a sensorimotor adaptability (SA) training program to facilitate rapid adaptation to novel gravitational environments. We have developed a unique training system comprised of a treadmill placed on a motion-base facing a virtual visual scene that provides an unstable walking surface combined with incongruent visual flow designed to enhance sensorimotor adaptability. We have conducted a series of studies that have shown: Training using a combination of modified visual flow and support surface motion during treadmill walking enhances locomotor adaptability to a novel sensorimotor environment. Trained individuals become more proficient at performing multiple competing tasks while walking during adaptation to novel discordant sensorimotor conditions. Trained subjects can retain their increased level of adaptability over a six months period. SA training is effective in producing increased adaptability in a more complex over-ground ambulatory task on an obstacle course. This confirms that for a complex task like walking, treadmill training contains enough of the critical features of overground walking to be an effective training modality. The structure of individual training sessions can be optimized to promote fast/strategic motor learning. Training sessions that each contain short-duration exposures to multiple perturbation stimuli allows subjects to acquire a greater ability to rapidly reorganize appropriate response strategies when encountering a novel sensory environment. Individual sensory biases (i.e. increased visual dependency) can predict adaptive responses to novel sensory environments suggesting that customized training prescriptions can be developed to enhance

  2. Area 5 influences excitability within the primary motor cortex in humans.

    Directory of Open Access Journals (Sweden)

    Azra Premji

    Full Text Available In non-human primates, Brodmann's area 5 (BA 5 has direct connectivity with primary motor cortex (M1, is largely dedicated to the representation of the hand and may have evolved with the ability to perform skilled hand movement. Less is known about human BA 5 and its interaction with M1 neural circuits related to hand control. The present study examines the influence of BA 5 on excitatory and inhibitory neural circuitry within M1 bilaterally before and after continuous (cTBS, intermittent (iTBS, and sham theta-burst stimulation (sham TBS over left hemisphere BA 5. Using single and paired-pulse TMS, measurements of motor evoked potentials (MEPs, short interval intracortical inhibition (SICI, and intracortical facilitation (ICF were quantified for the representation of the first dorsal interosseous muscle. Results indicate that cTBS over BA 5 influences M1 excitability such that MEP amplitudes are increased bilaterally for up to one hour. ITBS over BA 5 results in an increase in MEP amplitude contralateral to stimulation with a delayed onset that persists up to one hour. SICI and ICF were unaltered following TBS over BA 5. Similarly, F-wave amplitude and latency were unaltered following cTBS over BA 5. The data suggest that BA 5 alters M1 output directed to the hand by influencing corticospinal neurons and not interneurons that mediate SICI or ICF circuitry. Targeting BA 5 via cTBS and iTBS is a novel mechanism to powerfully modulate activity within M1 and may provide an avenue for investigating hand control in healthy populations and modifying impaired hand function in clinical populations.

  3. Spatial resolution dependence on spectral frequency in human speech cortex electrocorticography

    Science.gov (United States)

    Muller, Leah; Hamilton, Liberty S.; Edwards, Erik; Bouchard, Kristofer E.; Chang, Edward F.

    2016-10-01

    Objective. Electrocorticography (ECoG) has become an important tool in human neuroscience and has tremendous potential for emerging applications in neural interface technology. Electrode array design parameters are outstanding issues for both research and clinical applications, and these parameters depend critically on the nature of the neural signals to be recorded. Here, we investigate the functional spatial resolution of neural signals recorded at the human cortical surface. We empirically derive spatial spread functions to quantify the shared neural activity for each frequency band of the electrocorticogram. Approach. Five subjects with high-density (4 mm center-to-center spacing) ECoG grid implants participated in speech perception and production tasks while neural activity was recorded from the speech cortex, including superior temporal gyrus, precentral gyrus, and postcentral gyrus. The cortical surface field potential was decomposed into traditional EEG frequency bands. Signal similarity between electrode pairs for each frequency band was quantified using a Pearson correlation coefficient. Main results. The correlation of neural activity between electrode pairs was inversely related to the distance between the electrodes; this relationship was used to quantify spatial falloff functions for cortical subdomains. As expected, lower frequencies remained correlated over larger distances than higher frequencies. However, both the envelope and phase of gamma and high gamma frequencies (30-150 Hz) are largely uncorrelated (<90%) at 4 mm, the smallest spacing of the high-density arrays. Thus, ECoG arrays smaller than 4 mm have significant promise for increasing signal resolution at high frequencies, whereas less additional gain is achieved for lower frequencies. Significance. Our findings quantitatively demonstrate the dependence of ECoG spatial resolution on the neural frequency of interest. We demonstrate that this relationship is consistent across patients and

  4. GAD2 Alternative Transcripts in the Human Prefrontal Cortex, and in Schizophrenia and Affective Disorders.

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    Kasey N Davis

    Full Text Available Genetic variation and early adverse environmental events work together to increase risk for schizophrenia. γ-aminobutyric acid (GABA, the major inhibitory neurotransmitter in adult mammalian brain, plays a major role in normal brain development, and has been strongly implicated in the pathobiology of schizophrenia. GABA synthesis is controlled by two glutamic acid decarboxylase (GAD genes, GAD1 and GAD2, both of which produce a number of alternative transcripts. Genetic variants in the GAD1 gene are associated with increased risk for schizophrenia, and reduced expression of its major transcript in the human dorsolateral prefrontal cortex (DLPFC. No consistent changes in GAD2 expression have been found in brains from patients with schizophrenia. In this work, with the use of RNA sequencing and PCR technologies, we confirmed and tracked the expression of an alternative truncated transcript of GAD2 (ENST00000428517 in human control DLPFC homogenates across lifespan besides the well-known full length transcript of GAD2. In addition, using quantitative RT-PCR, expression of GAD2 full length and truncated transcripts were measured in the DLPFC of patients with schizophrenia, bipolar disorder and major depression. The expression of GAD2 full length transcript is decreased in the DLPFC of schizophrenia and bipolar disorder patients, while GAD2 truncated transcript is increased in bipolar disorder patients but decreased in schizophrenia patients. Moreover, the patients with schizophrenia with completed suicide or positive nicotine exposure showed significantly higher expression of GAD2 full length transcript. Alternative transcripts of GAD2 may be important in the growth and development of GABA-synthesizing neurons as well as abnormal GABA signaling in the DLPFC of patients with schizophrenia and affective disorders.

  5. A non-invasive, quantitative study of broadband spectral responses in human visual cortex.

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    Eline R Kupers

    Full Text Available Currently, non-invasive methods for studying the human brain do not routinely and reliably measure spike-rate-dependent signals, independent of responses such as hemodynamic coupling (fMRI and subthreshold neuronal synchrony (oscillations and event-related potentials. In contrast, invasive methods-microelectrode recordings and electrocorticography (ECoG-have recently measured broadband power elevation in field potentials (~50-200 Hz as a proxy for locally averaged spike rates. Here, we sought to detect and quantify stimulus-related broadband responses using magnetoencephalography (MEG. Extracranial measurements like MEG and EEG have multiple global noise sources and relatively low signal-to-noise ratios; moreover high frequency artifacts from eye movements can be confounded with stimulus design and mistaken for signals originating from brain activity. For these reasons, we developed an automated denoising technique that helps reveal the broadband signal of interest. Subjects viewed 12-Hz contrast-reversing patterns in the left, right, or bilateral visual field. Sensor time series were separated into evoked (12-Hz amplitude and broadband components (60-150 Hz. In all subjects, denoised broadband responses were reliably measured in sensors over occipital cortex, even in trials without microsaccades. The broadband pattern was stimulus-dependent, with greater power contralateral to the stimulus. Because we obtain reliable broadband estimates with short experiments (~20 minutes, and with sufficient signal-to-noise to distinguish responses to different stimuli, we conclude that MEG broadband signals, denoised with our method, offer a practical, non-invasive means for characterizing spike-rate-dependent neural activity for addressing scientific questions about human brain function.

  6. Learning to perceive in the sensorimotor approach: Piaget's theory of equilibration interpreted dynamically.

    Science.gov (United States)

    Di Paolo, Ezequiel Alejandro; Barandiaran, Xabier E; Beaton, Michael; Buhrmann, Thomas

    2014-01-01

    if understanding is required for perception, how can we learn to perceive something new, something we do not yet understand? According to the sensorimotor approach, perception involves mastery of regular sensorimotor co-variations that depend on the agent and the environment, also known as the "laws" of sensorimotor contingencies (SMCs). In this sense, perception involves enacting relevant sensorimotor skills in each situation. It is important for this proposal that such skills can be learned and refined with experience and yet up to this date, the sensorimotor approach has had no explicit theory of perceptual learning. The situation is made more complex if we acknowledge the open-ended nature of human learning. In this paper we propose Piaget's theory of equilibration as a potential candidate to fulfill this role. This theory highlights the importance of intrinsic sensorimotor norms, in terms of the closure of sensorimotor schemes. It also explains how the equilibration of a sensorimotor organization faced with novelty or breakdowns proceeds by re-shaping pre-existing structures in coupling with dynamical regularities of the world. This way learning to perceive is guided by the equilibration of emerging forms of skillful coping with the world. We demonstrate the compatibility between Piaget's theory and the sensorimotor approach by providing a dynamical formalization of equilibration to give an explicit micro-genetic account of sensorimotor learning and, by extension, of how we learn to perceive. This allows us to draw important lessons in the form of general principles for open-ended sensorimotor learning, including the need for an intrinsic normative evaluation by the agent itself. We also explore implications of our micro-genetic account at the personal level.

  7. Learning to perceive in the sensorimotor approach: Piaget's theory of equilibration interpreted dynamically

    Directory of Open Access Journals (Sweden)

    Ezequiel Alejandro Di Paolo

    2014-07-01

    Full Text Available Learning to perceive faces a classical paradox: if understanding is required for perception, how can we learn to perceive something new, something we do not yet understand? According to the sensorimotor approach, perception involves mastery of regular sensorimotor co-variations that depend on the agent and the environment, also known as the ‘laws’ of sensorimotor contingencies. In this sense, perception involves enacting relevant sensorimotor skills in each situation. It is important for this proposal that such skills can be learned and refined with experience and yet up to this date, the sensorimotor approach has had no explicit theory of perceptual learning. The situation is made more complex if we acknowledge the open-ended nature of human learning. In this paper we propose Piaget’s theory of equilibration as a potential candidate to fulfill this role. This theory highlights the importance of intrinsic sensorimotor norms, in terms of the closure of sensorimotor schemes. It also explains how the equilibration of a sensorimotor organization faced with novelty or breakdowns proceeds by re-shaping pre-existing structures in coupling with dynamical regularities of the world. This way learning to perceive is guided by the equilibration of emerging forms of skillful coping with the world. We demonstrate the compatibility between Piaget’s theory and the sensorimotor approach by providing a dynamical formalization of equilibration to give an explicit micro-genetic account of sensorimotor learning and, by extension, of how we learn to perceive. This allows us to draw important lessons in the form of general principles for open-ended sensorimotor learning, including the need for an intrinsic normative evaluation by the agent itself. We also explore implications of our micro-genetic account at the personal level.

  8. Evidence for Non-Opponent Coding of Colour Information in Human Visual Cortex: Selective Loss of "Green" Sensitivity in a Subject with Damaged Ventral Occipito-Temporal Cortex.

    Science.gov (United States)

    Rauscher, Franziska G; Plant, Gordon T; James-Galton, Merle; Barbur, John L

    2011-01-01

    Damage to ventral occipito-temporal extrastriate visual cortex leads to the syndrome of prosopagnosia often with coexisting cerebral achromatopsia. A patient with this syndrome resulting in a left upper homonymous quadrantanopia, prosopagnosia, and incomplete achromatopsia is described. Chromatic sensitivity was assessed at a number of locations in the intact visual field using a dynamic luminance contrast masking technique that isolates the use of colour signals. In normal subjects chromatic detection thresholds form an elliptical contour when plotted in the Commission Internationale d'Eclairage, (x-y), chromaticity diagram. Because the extraction of colour signals in early visual processing involves opponent mechanisms, subjects with Daltonism (congenital red/green loss of sensitivity) show symmetric increase in thresholds towards the long wavelength ("red") and middle wavelength ("green") regions of the spectrum locus. This is also the case with acquired loss of chromatic sensitivity as a result of retinal or optic nerve disease. Our patient's results were an exception to this rule. Whilst his chromatic sensitivity in the central region of the visual field was reduced symmetrically for both "red/green" and "yellow/blue" directions in colour space, the subject's lower left quadrant showed a marked asymmetry in "red/green" thresholds with the greatest loss of sensitivity towards the "green" region of the spectrum locus. This spatially localized asymmetric loss of "green" but not "red" sensitivity has not been reported previously in human vision. Such loss is consistent with selective damage of neural substrates in the visual cortex that process colour information, but are spectrally non-opponent.

  9. Avalanche analysis from multi-electrode ensemble recordings in cat, monkey and human cerebral cortex during wakefulness and sleep.

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    Nima eDehghani

    2012-08-01

    Full Text Available Self-organized critical states are found in many natural systems, from earthquakes to forest fires, they have also been observed in neural systems, particularly, in neuronal cultures. However, the presence of critical states in the awake brain remains controversial. Here, we compared avalanche analyses performed on different in vivo preparations during wakefulness, slow-wave sleep and REM sleep, using high-density electrode arrays in cat motor cortex (96 electrodes, monkey motor cortex and premotor cortex and human temporal cortex (96 electrodes in epileptic patients. In neuronal avalanches defined from units (up to 160 single units, the size of avalanches never clearly scaled as power-law, but rather scaled exponentially or displayed intermediate scaling. We also analyzed the dynamics of local field potentials (LFPs and in particular LFP negative peaks (nLFPs among the different electrodes (up to 96 sites in temporal cortex or up to 128 sites in adjacent motor and pre-motor cortices. In this case, the avalanches defined from nLFPs displayed power-law scaling in double logarithmic representations, as reported previously in monkey. However, avalanche defined as positive LFP (pLFP peaks, which are less directly related to neuronal firing, also displayed apparent power-law scaling. Closer examination of this scaling using the more reliable cumulative distribution function (CDF and other rigorous statistical measures, did not confirm power-law scaling. The same pattern was seen for cats, monkey and human, as well as for different brain states of wakefulness and sleep. We also tested other alternative distributions. Multiple exponential fitting yielded optimal fits of the avalanche dynamics with bi-exponential distributions. Collectively, these results show no clear evidence for power-law scaling or self-organized critical states in the awake and sleeping brain of mammals, from cat to man.

  10. Frequency-specific attentional modulation in human primary auditory cortex and midbrain

    NARCIS (Netherlands)

    Riecke, Lars; Peters, Judith C; Valente, Giancarlo; Poser, Benedikt A; Kemper, Valentin G; Formisano, Elia; Sorger, Bettina

    2018-01-01

    Paying selective attention to an audio frequency selectively enhances activity within primary auditory cortex (PAC) at the tonotopic site (frequency channel) representing that frequency. Animal PAC neurons achieve this 'frequency-specific attentional spotlight' by adapting their frequency tuning,

  11. Induction of plasticity in the human motor cortex by pairing an auditory stimulus with TMS

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    Paul Fredrick Sowman

    2014-06-01

    Full Text Available Acoustic stimuli can cause a transient increase in the excitability of the motor cortex. The current study leverages this phenomenon to develop a method for testing the integrity of auditorimotor integration and the capacity for auditorimotor plasticity. We demonstrate that appropriately timed transcranial magnetic stimulation (TMS of the hand area, paired with auditorily mediated excitation of the motor cortex, induces an enhancement of motor cortex excitability that lasts beyond the time of stimulation. This result demonstrates for the first time that paired associative stimulation (PAS -induced plasticity within the motor cortex is applicable with auditory stimuli. We propose that the method developed here might provide a useful tool for future studies that measure auditory-motor connectivity in communication disorders.

  12. Persistent neural activity in auditory cortex is related to auditory working memory in humans and nonhuman primates.

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    Huang, Ying; Matysiak, Artur; Heil, Peter; König, Reinhard; Brosch, Michael

    2016-07-20

    Working memory is the cognitive capacity of short-term storage of information for goal-directed behaviors. Where and how this capacity is implemented in the brain are unresolved questions. We show that auditory cortex stores information by persistent changes of neural activity. We separated activity related to working memory from activity related to other mental processes by having humans and monkeys perform different tasks with varying working memory demands on the same sound sequences. Working memory was reflected in the spiking activity of individual neurons in auditory cortex and in the activity of neuronal populations, that is, in local field potentials and magnetic fields. Our results provide direct support for the idea that temporary storage of information recruits the same brain areas that also process the information. Because similar activity was observed in the two species, the cellular bases of some auditory working memory processes in humans can be studied in monkeys.

  13. Implied motion because of instability in Hokusai Manga activates the human motion-sensitive extrastriate visual cortex: an fMRI study of the impact of visual art.

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    Osaka, Naoyuki; Matsuyoshi, Daisuke; Ikeda, Takashi; Osaka, Mariko

    2010-03-10

    The recent development of cognitive neuroscience has invited inference about the neurosensory events underlying the experience of visual arts involving implied motion. We report functional magnetic resonance imaging study demonstrating activation of the human extrastriate motion-sensitive cortex by static images showing implied motion because of instability. We used static line-drawing cartoons of humans by Hokusai Katsushika (called 'Hokusai Manga'), an outstanding Japanese cartoonist as well as famous Ukiyoe artist. We found 'Hokusai Manga' with implied motion by depicting human bodies that are engaged in challenging tonic posture significantly activated the motion-sensitive visual cortex including MT+ in the human extrastriate cortex, while an illustration that does not imply motion, for either humans or objects, did not activate these areas under the same tasks. We conclude that motion-sensitive extrastriate cortex would be a critical region for perception of implied motion in instability.

  14. Enhancing Astronaut Performance using Sensorimotor Adaptability Training

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    Jacob J Bloomberg

    2015-09-01

    Full Text Available Astronauts experience disturbances in balance and gait function when they return to Earth. The highly plastic human brain enables individuals to modify their behavior to match the prevailing environment. Subjects participating in specially designed variable sensory challenge training programs can enhance their ability to rapidly adapt to novel sensory situations. This is useful in our application because we aim to train astronauts to rapidly formulate effective strategies to cope with the balance and locomotor challenges associated with new gravitational environments - enhancing their ability to learn to learn. We do this by coupling various combinations of sensorimotor challenges with treadmill walking. A unique training system has been developed that is comprised of a treadmill mounted on a motion base to produce movement of the support surface during walking. This system provides challenges to gait stability. Additional sensory variation and challenge are imposed with a virtual visual scene that presents subjects with various combinations of discordant visual information during treadmill walking. This experience allows them to practice resolving challenging and conflicting novel sensory information to improve their ability to adapt rapidly. Information obtained from this work will inform the design of the next generation of sensorimotor countermeasures for astronauts.

  15. Enhancing astronaut performance using sensorimotor adaptability training.

    Science.gov (United States)

    Bloomberg, Jacob J; Peters, Brian T; Cohen, Helen S; Mulavara, Ajitkumar P

    2015-01-01

    Astronauts experience disturbances in balance and gait function when they return to Earth. The highly plastic human brain enables individuals to modify their behavior to match the prevailing environment. Subjects participating in specially designed variable sensory challenge training programs can enhance their ability to rapidly adapt to novel sensory situations. This is useful in our application because we aim to train astronauts to rapidly formulate effective strategies to cope with the balance and locomotor challenges associated with new gravitational environments-enhancing their ability to "learn to learn." We do this by coupling various combinations of sensorimotor challenges with treadmill walking. A unique training system has been developed that is comprised of a treadmill mounted on a motion base to produce movement of the support surface during walking. This system provides challenges to gait stability. Additional sensory variation and challenge are imposed with a virtual visual scene that presents subjects with various combinations of discordant visual information during treadmill walking. This experience allows them to practice resolving challenging and conflicting novel sensory information to improve their ability to adapt rapidly. Information obtained from this work will inform the design of the next generation of sensorimotor countermeasures for astronauts.

  16. Evidence for cue-independent spatial representation in the human auditory cortex during active listening.

    Science.gov (United States)

    Higgins, Nathan C; McLaughlin, Susan A; Rinne, Teemu; Stecker, G Christopher

    2017-09-05

    Few auditory functions are as important or as universal as the capacity for auditory spatial awareness (e.g., sound localization). That ability relies on sensitivity to acoustical cues-particularly interaural time and level differences (ITD and ILD)-that correlate with sound-source locations. Under nonspatial listening conditions, cortical sensitivity to ITD and ILD takes the form of broad contralaterally dominated response functions. It is unknown, however, whether that sensitivity reflects representations of the specific physical cues or a higher-order representation of auditory space (i.e., integrated cue processing), nor is it known whether responses to spatial cues are modulated by active spatial listening. To investigate, sensitivity to parametrically varied ITD or ILD cues was measured using fMRI during spatial and nonspatial listening tasks. Task type varied across blocks where targets were presented in one of three dimensions: auditory location, pitch, or visual brightness. Task effects were localized primarily to lateral posterior superior temporal gyrus (pSTG) and modulated binaural-cue response functions differently in the two hemispheres. Active spatial listening (location tasks) enhanced both contralateral and ipsilateral responses in the right hemisphere but maintained or enhanced contralateral dominance in the left hemisphere. Two observations suggest integrated processing of ITD and ILD. First, overlapping regions in medial pSTG exhibited significant sensitivity to both cues. Second, successful classification of multivoxel patterns was observed for both cue types and-critically-for cross-cue classification. Together, these results suggest a higher-order representation of auditory space in the human auditory cortex that at least partly integrates the specific underlying cues.

  17. Prandial states modify the reactivity of the gustatory cortex using gustatory evoked potentials in humans

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    Agnès eJACQUIN-PIQUES

    2016-01-01

    Full Text Available Previous functional Magnetic Resonance Imaging studies evaluated the role of satiety on cortical taste area activity and highlighted decreased activation in the orbito-frontal cortex when food was eaten until satiation. The modulation of orbito-frontal neurons (secondary taste area by ad libitum food intake has been associated with the pleasantness of the food’s flavor. The insula and frontal operculum (primary taste area are also involved in reward processing. The aim was to compare human gustatory evoked potentials (GEP recorded in the primary and secondary gustatory cortices in a fasted state with those after food intake. Fifteen healthy volunteers were enrolled in this observational study. In each of two sessions, two GEP recordings were performed (at 11:00 am and 1:30 pm in response to sucrose gustatory stimulation, and a sucrose-gustatory threshold was determined. During one session, a standard lunch was provided between the two GEP recordings. During the other session, subjects had nothing to eat. Hunger sensation, wanting, liking and the perception of the solution’s intensity were evaluated with visual analogue scales. GEP latencies measured in the Pz (p<0.001, Cz (p<0.01, Fz (p<0.001 recordings (primary taste area were longer after lunch than in the pre-prandial condition. Fp1 and Fp2 latencies (secondary taste area tended to be longer after lunch, but the difference was not significant. No difference was observed for the sucrose-gustatory threshold regardless of the session and time. Modifications in the primary taste area activity during the post-prandial period occurred regardless of the nature of the food eaten and could represent the activity of the frontal operculum and insula, which was recently shown to be modulated by gut signals (GLP-1, CCK, ghrelin, or insulin through vagal afferent neurons or metabolic changes of the internal milieu after nutrient absorption. This trial was registered at clinicalstrials.gov as NCT

  18. Monaural and binaural contributions to interaural-level-difference sensitivity in human auditory cortex.

    Science.gov (United States)

    Stecker, G Christopher; McLaughlin, Susan A; Higgins, Nathan C

    2015-10-15

    Whole-brain functional magnetic resonance imaging was used to measure blood-oxygenation-level-dependent (BOLD) responses in human auditory cortex (AC) to sounds with intensity varying independently in the left and right ears. Echoplanar images were acquired at 3 Tesla with sparse image acquisition once per 12-second block of sound stimulation. Combinations of binaural intensity and stimulus presentation rate were varied between blocks, and selected to allow measurement of response-intensity functions in three configurations: monaural 55-85 dB SPL, binaural 55-85 dB SPL with intensity equal in both ears, and binaural with average binaural level of 70 dB SPL and interaural level differences (ILD) ranging ±30 dB (i.e., favoring the left or right ear). Comparison of response functions equated for contralateral intensity revealed that BOLD-response magnitudes (1) generally increased with contralateral intensity, consistent with positive drive of the BOLD response by the contralateral ear, (2) were larger for contralateral monaural stimulation than for binaural stimulation, consistent with negative effects (e.g., inhibition) of ipsilateral input, which were strongest in the left hemisphere, and (3) also increased with ipsilateral intensity when contralateral input was weak, consistent with additional, positive, effects of ipsilateral stimulation. Hemispheric asymmetries in the spatial extent and overall magnitude of BOLD responses were generally consistent with previous studies demonstrating greater bilaterality of responses in the right hemisphere and stricter contralaterality in the left hemisphere. Finally, comparison of responses to fast (40/s) and slow (5/s) stimulus presentation rates revealed significant rate-dependent adaptation of the BOLD response that varied across ILD values. Copyright © 2015. Published by Elsevier Inc.

  19. Sensorimotor Network Crucial for Inferring Amusement from Smiles.

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    Paracampo, Riccardo; Tidoni, Emmanuele; Borgomaneri, Sara; di Pellegrino, Giuseppe; Avenanti, Alessio

    2017-11-01

    Understanding whether another's smile reflects authentic amusement is a key challenge in social life, yet, the neural bases of this ability have been largely unexplored. Here, we combined transcranial magnetic stimulation (TMS) with a novel empathic accuracy (EA) task to test whether sensorimotor and mentalizing networks are critical for understanding another's amusement. Participants were presented with dynamic displays of smiles and explicitly requested to infer whether the smiling individual was feeling authentic amusement or not. TMS over sensorimotor regions representing the face (i.e., in the inferior frontal gyrus (IFG) and ventral primary somatosensory cortex (SI)), disrupted the ability to infer amusement authenticity from observed smiles. The same stimulation did not affect performance on a nonsocial task requiring participants to track the smiling expression but not to infer amusement. Neither TMS over prefrontal and temporo-parietal areas supporting mentalizing, nor peripheral control stimulations, affected performance on either task. Thus, motor and somatosensory circuits for controlling and sensing facial movements are causally essential for inferring amusement from another's smile. These findings highlight the functional relevance of IFG and SI to amusement understanding and suggest that EA abilities may be grounded in sensorimotor networks for moving and feeling the body. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  20. The contribution of CXCL12-expressing radial glia cells to neuro-vascular patterning during human cerebral cortex development

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    Mariella eErrede

    2014-10-01

    Full Text Available This study was conducted on human developing brain by laser confocal and transmission electron microscopy to make a detailed analysis of important features of blood-brain barrier microvessels and possible control mechanisms of vessel growth and differentiation during cerebral cortex vascularization. The blood-brain barrier status of cortex microvessels was examined at a defined stage of cortex development, at the end of neuroblast waves of migration and before cortex lamination, with blood-brain barrier-endothelial cell markers, namely tight junction proteins (occludin and claudin-5 and influx and efflux transporters (Glut-1 and P-glycoprotein, the latter supporting evidence for functional effectiveness of the fetal blood-brain barrier. According to the well-known roles of astroglia cells on microvessel growth and differentiation, the early composition of astroglia/endothelial cell relationships was analysed by detecting the appropriate astroglia, endothelial, and pericyte markers. GFAP, chemokine CXCL12, and connexin 43 (Cx43 were utilized as markers of radial glia cells, CD105 (endoglin as a marker of angiogenically activated endothelial cells, and proteoglycan NG2 as a marker of immature pericytes. Immunolabeling for CXCL12 showed the highest level of the ligand in radial glial fibres in contact with the growing cortex microvessels. These specialized contacts, recognizable on both perforating radial vessels and growing collaterals, appeared as CXCL12-reactive en passant, symmetrical and asymmetrical vessel-specific RG fibre swellings. At the highest confocal resolution, these RG varicosities showed a CXCL12-reactive dot-like content whose microvesicular nature was confirmed by ultrastructural observations. A further analysis of radial glial varicosities reveals colocalization of CXCL12 with connexin Cx43, which is possibly implicated in vessel-specific chemokine signalling.

  1. Does an intraneural interface short-term implant for robotic hand control modulate sensorimotor cortical integration? An EEG-TMS co-registration study on a human amputee.

    Science.gov (United States)

    Ferreri, F; Ponzo, D; Vollero, L; Guerra, A; Di Pino, G; Petrichella, S; Benvenuto, A; Tombini, M; Rossini, L; Denaro, L; Micera, S; Iannello, G; Guglielmelli, E; Denaro, V; Rossini, P M

    2014-01-01

    Following limb amputation, central and peripheral nervous system relays partially maintain their functions and can be exploited for interfacing prostheses. The aim of this study is to investigate, for the first time by means of an EEG-TMS co-registration study, whether and how direct bidirectional connection between brain and hand prosthesis impacts on sensorimotor cortical topography. Within an experimental protocol for robotic hand control, a 26 years-old, left-hand amputated male was selected to have implanted four intrafascicular electrodes (tf-LIFEs-4) in the median and ulnar nerves of the stump for 4 weeks. Before tf-LIFE-4s implant (T0) and after the training period, once electrodes have been removed (T1), experimental subject's cortico-cortical excitability, connectivity and plasticity were tested via a neuronavigated EEG-TMS experiment. The statistical analysis clearly demonstrated a significant modulation (with t-test p < 0.0001) of EEG activity between 30 and 100 ms post-stimulus for the stimulation of the right hemisphere. When studying individual latencies in that time range, a global amplitude modulation was found in most of the TMS-evoked potentials; particularly, the GEE analysis showed significant differences between T0 and T1 condition at 30 ms (p < 0.0404), 46 ms (p < 0.0001) and 60 ms (p < 0.007) latencies. Finally, also a clear local decrement in N46 amplitude over C4 was evident. No differences between conditions were observed for the stimulation of the left hemisphere. The results of this study confirm the hypothesis that bidirectional neural interface could redirect cortical areas -deprived of their original input/output functions- toward restorative neuroplasticity. This reorganization strongly involves bi-hemispheric networks and intracortical and transcortical modulation of GABAergic inhibition.

  2. Ventromedial Frontal Cortex Is Critical for Guiding Attention to Reward-Predictive Visual Features in Humans.

    Science.gov (United States)

    Vaidya, Avinash R; Fellows, Lesley K

    2015-09-16

    Adaptively interacting with our environment requires extracting information that will allow us to successfully predict reward. This can be a challenge, particularly when there are many candidate cues, and when rewards are probabilistic. Recent work has demonstrated that visual attention is allocated to stimulus features that have been associated with reward on previous trials. The ventromedial frontal lobe (VMF) has been implicated in learning in dynamic environments of this kind, but the mechanism by which this region influences this process is not clear. Here, we hypothesized that the VMF plays a critical role in guiding attention to reward-predictive stimulus features based on feedback. We tested the effects of VMF damage in human subjects on a visual search task in which subjects were primed to attend to task-irrelevant colors associated with different levels of reward, incidental to the search task. Consistent with previous work, we found that distractors had a greater influence on reaction time when they appeared in colors associated with high reward in the previous trial compared with colors associated with low reward in healthy control subjects and patients with prefrontal damage sparing the VMF. However, this reward modulation of attentional priming was absent in patients with VMF damage. Thus, an intact VMF is necessary for directing attention based on experience with cue-reward associations. We suggest that this region plays a role in selecting reward-predictive cues to facilitate future learning. There has been a swell of interest recently in the ventromedial frontal cortex (VMF), a brain region critical to associative learning. However, the underlying mechanism by which this region guides learning is not well understood. Here, we tested the effects of damage to this region in humans on a task in which rewards were linked incidentally to visual features, resulting in trial-by-trial attentional priming. Controls and subjects with prefrontal damage

  3. Short-term and long-term plasticity interaction in human primary motor cortex.

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    Iezzi, Ennio; Suppa, Antonio; Conte, Antonella; Li Voti, Pietro; Bologna, Matteo; Berardelli, Alfredo

    2011-05-01

    Repetitive transcranial magnetic stimulation (rTMS) over primary motor cortex (M1) elicits changes in motor evoked potential (MEP) size thought to reflect short- and long-term forms of synaptic plasticity, resembling short-term potentiation (STP) and long-term potentiation/depression (LTP/LTD) observed in animal experiments. We designed this study in healthy humans to investigate whether STP as elicited by 5-Hz rTMS interferes with LTP/LTD-like plasticity induced by intermittent and continuous theta-burst stimulation (iTBS and cTBS). The effects induced by 5-Hz rTMS and iTBS/cTBS were indexed as changes in MEP size. We separately evaluated changes induced by 5-Hz rTMS, iTBS and cTBS applied alone and those induced by iTBS and cTBS delivered after priming 5-Hz rTMS. Interactions between 5-Hz rTMS and iTBS/cTBS were investigated under several experimental conditions by delivering 5-Hz rTMS at suprathreshold and subthreshold intensity, allowing 1 and 5 min intervals to elapse between 5-Hz rTMS and TBS, and delivering one and ten 5-Hz rTMS trains. We also investigated whether 5-Hz rTMS induces changes in intracortical excitability tested with paired-pulse transcranial magnetic stimulation. When given alone, 5-Hz rTMS induced short-lasting and iTBS/cTBS induced long-lasting changes in MEP amplitudes. When M1 was primed with 10 suprathreshold 5-Hz rTMS trains at 1 min before iTBS or cTBS, the iTBS/cTBS-induced after-effects disappeared. The 5-Hz rTMS left intracortical excitability unchanged. We suggest that STP elicited by suprathreshold 5-Hz rTMS abolishes iTBS/cTBS-induced LTP/LTD-like plasticity through non-homeostatic metaplasticity mechanisms. Our study provides new information on interactions between short-term and long-term rTMS-induced plasticity in human M1. © 2011 The Authors. European Journal of Neuroscience © 2011 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

  4. Walk-related mimic word activates the extrastriate visual cortex in the human brain: an fMRI study.

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    Osaka, Naoyuki

    2009-03-02

    I present an fMRI study demonstrating that a mimic word highly suggestive of human walking, heard by the ear with eyes closed, significantly activates the visual cortex located in extrastriate occipital region (BA19, 18) and superior temporal sulcus (STS) while hearing non-sense words that do not imply walk under the same task does not activate these areas in humans. I concluded that BA19 and 18 would be a critical region for generating visual images of walking and related intentional stance, respectively, evoked by an onomatopoeia word that implied walking.

  5. Functional organization of the face-sensitive areas in human occipital-temporal cortex.

    Science.gov (United States)

    Shao, Hanyu; Weng, Xuchu; He, Sheng

    2017-08-15

    Human occipital-temporal cortex features several areas sensitive to faces, presumably forming the biological substrate for face perception. To date, there are piecemeal insights regarding the functional organization of these regions. They have come, however, from studies that are far from homogeneous with regard to the regions involved, the experimental design, and the data analysis approach. In order to provide an overall view of the functional organization of the face-sensitive areas, it is necessary to conduct a comprehensive study that taps into the pivotal functional properties of all the face-sensitive areas, within the context of the same experimental design, and uses multiple data analysis approaches. In this study, we identified the most robustly activated face-sensitive areas in bilateral occipital-temporal cortices (i.e., AFP, aFFA, pFFA, OFA, pcSTS, pSTS) and systemically compared their regionally averaged activation and multivoxel activation patterns to 96 images from 16 object categories, including faces and non-faces. This condition-rich and single-image analysis approach critically samples the functional properties of a brain region, allowing us to test how two basic functional properties, namely face-category selectivity and face-exemplar sensitivity are distributed among these regions. Moreover, by examining the correlational structure of neural responses to the 96 images, we characterize their interactions in the greater face-processing network. We found that (1) r-pFFA showed the highest face-category selectivity, followed by l-pFFA, bilateral aFFA and OFA, and then bilateral pcSTS. In contrast, bilateral AFP and pSTS showed low face-category selectivity; (2) l-aFFA, l-pcSTS and bilateral AFP showed evidence of face-exemplar sensitivity; (3) r-OFA showed high overall response similarities with bilateral LOC and r-pFFA, suggesting it might be a transitional stage between general and face-selective information processing; (4) r-aFFA showed high

  6. Regions of mid-level human visual cortex sensitive to the global coherence of local image patches.

    Science.gov (United States)

    Mannion, Damien J; Kersten, Daniel J; Olman, Cheryl A

    2014-08-01

    The global structural arrangement and spatial layout of the visual environment must be derived from the integration of local signals represented in the lower tiers of the visual system. This interaction between the spatially local and global properties of visual stimulation underlies many of our visual capacities, and how this is achieved in the brain is a central question for visual and cognitive neuroscience. Here, we examine the sensitivity of regions of the posterior human brain to the global coordination of spatially displaced naturalistic image patches. We presented observers with image patches in two circular apertures to the left and right of central fixation, with the patches drawn from either the same (coherent condition) or different (noncoherent condition) extended image. Using fMRI at 7T (n = 5), we find that global coherence affected signal amplitude in regions of dorsal mid-level cortex. Furthermore, we find that extensive regions of mid-level visual cortex contained information in their local activity pattern that could discriminate coherent and noncoherent stimuli. These findings indicate that the global coordination of local naturalistic image information has important consequences for the processing in human mid-level visual cortex.

  7. Thalamic deactivation at sleep onset precedes that of the cerebral cortex in humans

    Science.gov (United States)

    Magnin, Michel; Rey, Marc; Bastuji, Hélène; Guillemant, Philippe; Mauguière, François; Garcia-Larrea, Luis

    2010-01-01

    Thalamic and cortical activities are assumed to be time-locked throughout all vigilance states. Using simultaneous intracortical and intrathalamic recordings, we demonstrate here that the thalamic deactivation occurring at sleep onset most often precedes that of the cortex by several minutes, whereas reactivation of both structures during awakening is synchronized. Delays between thalamus and cortex deactivations can vary from one subject to another when a similar cortical region is considered. In addition, heterogeneity in activity levels throughout the cortical mantle is larger than previously thought during the descent into sleep. Thus, asynchronous thalamo-cortical deactivation while falling asleep probably explains the production of hypnagogic hallucinations by a still-activated cortex and the common self-overestimation of the time needed to fall asleep. PMID:20142493

  8. Double-bouquet cells in the monkey and human cerebral cortex with special reference to areas 17 and 18.

    Science.gov (United States)

    DeFelipe, Javier; Ballesteros-Yáñez, Inmaculada; Inda, Maria Carmen; Muñoz, Alberto

    2006-01-01

    The detailed microanatomical study of the human cerebral cortex began in 1899 with the experiments of Santiago Ramón y Cajal, who applied the Golgi method to define the structure of the visual, motor, auditory and olfactory cortex. In the first article of this series, he described a special type of interneuron in the visual cortex capable of exerting its influence in the vertical dimension. These neurons are now more commonly referred to as double-bouquet cells (DBCs). The DBCs are readily distinguished owing to their characteristic axons that give rise to tightly interwoven bundles of long, vertically oriented axonal collaterals resembling a horsetail (DBC horsetail). Nevertheless, the most striking characteristic of these neurons is that they are so numerous and regularly distributed that the DBC horsetails form a microcolumnar structure. In addition, DBCs establish hundreds of inhibitory synapses within a very narrow column of cortical tissue. These features have generated considerable interest in DBCs over recent years, principally among those researchers interested in the analysis of cortical circuits. In the present chapter, we shall discuss the morphology, synaptic connections and neurochemical features of DBCs that have been defined through the study of these cells in different cortical areas and species. We will mainly consider the immunocytochemical studies of DBCs that have been carried out in the visual cortex (areas 17 and 18) of human and macaque monkey. We will see that there are important differences in the morphology, number and distribution of DBC horsetails between areas 17 and 18 in the primate. This suggests important differences in the microcolumnar organization between these areas, the functional significance of which awaits detailed correlative physiological and microanatomical studies.

  9. Motor Skills Training Improves Sensorimotor Dysfunction and Increases Microtubule-Associated Protein 2 mRNA Expression in Rats with Intracerebral Hemorrhage.

    Science.gov (United States)

    Tamakoshi, Keigo; Kawanaka, Kentaro; Onishi, Hideaki; Takamatsu, Yasuyuki; Ishida, Kazuto

    2016-08-01

    In this study, we examined the effects of motor skills training on the sensorimotor function and the expression of genes associated with synaptic plasticity after intracerebral hemorrhage (ICH) in rats. Male Wistar rats were subjected to ICH or sham operation. ICH was caused by the injection of collagenase into the left striatum. Rats were randomly assigned to no training, acrobatic training, and sham groups. The acrobatic group performed 5 types of acrobatic tasks from 4 to 28 days after surgery. The forelimb sensorimotor function was evaluated over time using forepaw grasping, forelimb placing, and postural instability tests. At 14 and 29 days after the lesion, we analyzed the mRNA expression levels of microtubule-associated protein 2 (MAP2), brain-derived neurotrophic factor, and growth-associated protein 43 in the bilateral sensorimotor cortex (forelimb area) by real-time reverse transcription-polymerase chain reaction. Motor skills training in ICH rats improved the sensorimotor dysfunction significantly from the early phase. The mRNA expression level of MAP2 was upregulated in the ipsilesional sensorimotor cortex by motor skills training at 29 days after the lesion. Our results suggest that sensorimotor functional recovery following motor skills training after ICH is promoted by dendritic growth in the ipsilesional sensorimotor cortex. Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  10. Safety and feasibility of transcranial direct current stimulation (tDCS) combined with sensorimotor retraining in chronic low back pain: a protocol for a pilot randomised controlled trial.

    Science.gov (United States)

    Ouellette, Adam Louis; Liston, Matthew B; Chang, Wei-Ju; Walton, David M; Wand, Benedict Martin; Schabrun, Siobhan M

    2017-08-21

    Chronic low back pain (LBP) is a common and costly health problem yet current treatments demonstrate at best, small effects. The concurrent application of treatments with synergistic clinical and mechanistic effects may improve outcomes in chronic LBP. This pilot trial aims to (1) determine the feasibility, safety and perceived patient response to a combined transcranial direct current stimulation (tDCS) and sensorimotor retraining intervention in chronic LBP and (2) provide data to support a sample size calculation for a fully powered trial should trends of effectiveness be present. A pilot randomised, assessor and participant-blind, sham-controlled trial will be conducted. Eighty participants with chronic LBP will be randomly allocated to receive either (1) active tDCS + sensorimotor retraining or (2) sham tDCS + sensorimotor retraining. tDCS (active or sham) will be applied to the primary motor cortex for 20 min immediately prior to 60 min of supervised sensorimotor retraining twice per week for 10 weeks. Participants in both groups will complete home exercises three times per week. Feasibility, safety, pain, disability and pain system function will be assessed immediately before and after the 10-week intervention. Analysis of feasibility and safety will be performed using descriptive statistics. Statistical analyses will be conducted based on intention-to-treat and per protocol and will be used to determine trends for effectiveness. Ethical approval has been gained from the institutional human research ethics committee (H10184). Written informed consent will be provided by all participants. Results from this pilot study will be submitted for publication in peer-reviewed journals. ACTRN12616000624482. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  11. Porosity, Mineralization, Tissue Type and Morphology Interactions at the Human Tibial Cortex

    Science.gov (United States)

    Hampson, Naomi A.

    Prior research has shown a relationship between tibia robustness (ratio of cross-sectional area to bone length) and stress fracture risk, with less robust bones having a higher risk, which may indicate a compensatory increase in elastic modulus to increase bending strength. Previous studies of human tibiae have shown higher ash content in slender bones. In this study, the relationships between variations in volumetric porosity, ash content, tissue mineral density, secondary bone tissue, and cross sectional geometry, were investigated in order to better understand the tissue level adaptations that may occur in the establishment of cross-sectional properties. In this research, significant differences were found between porosity, ash content, and tissue type around the cortex between robust and slender bones, suggesting that there was a level of co-adaption occurring. Variation in porosity correlated with robustness, and explained large parts of the variation in tissue mineral density. The nonlinear relationship between porosity and ash content may support that slender bones compensate for poor geometry by increasing ash content through reduced remodeling, while robust individuals increase porosity to decrease mass, but only to a point. These results suggest that tissue level organization plays a compensatory role in the establishment of adult bone mass, and may contribute to differences in bone aging between different bone phenotypes. The results suggest that slender individuals have significantly less remodeled bone, however the proportion of remodeled bone was not uniform around the tibia. In the complex results of the study of 38% vs. 66% sites the distal site was subject to higher strains than the 66% site, indicating both local and global regulators may be affecting overall remodeling rates and need to be teased apart in future studies. This research has broad clinical implications on the diagnosis and treatment of fragility fractures. The relationships that

  12. Mapping of the brain hemodynamic responses to sensorimotor stimulation in a rodent model: A BOLD fMRI study.

    Directory of Open Access Journals (Sweden)

    Salem Boussida

    Full Text Available Blood Oxygenation Level Dependent functional MRI (BOLD fMRI during electrical paw stimulation has been widely used in studies aimed at the understanding of the somatosensory network in rats. However, despite the well-established anatomical connections between cortical and subcortical structures of the sensorimotor system, most of these functional studies have been concentrated on the cortical effects of sensory electrical stimulation. BOLD fMRI study of the integration of a sensorimotor input across the sensorimotor network requires an appropriate methodology to elicit functional activation in cortical and subcortical areas owing to the regional differences in both neuronal and vascular architectures between these brain regions. Here, using a combination of low level anesthesia, long pulse duration of the electrical stimulation along with improved spatial and temporal signal to noise ratios, we provide a functional description of the main cortical and subcortical structures of the sensorimotor rat brain. With this calibrated fMRI protocol, unilateral non-noxious sensorimotor electrical hindpaw stimulation resulted in robust positive activations in the contralateral sensorimotor cortex and bilaterally in the sensorimotor thalamus nuclei, whereas negative activations were observed bilaterally in the dorsolateral caudate-putamen. These results demonstrate that, once the experimental setup allowing necessary spatial and temporal signal to noise ratios is reached, hemodynamic changes related to neuronal activity, as preserved by the combination of a soft anesthesia with a soft muscle relaxation, can be measured within the sensorimotor network. Moreover, the observed responses suggest that increasing pulse duration of the electrical stimulus adds a proprioceptive component to the sensory input that activates sensorimotor network in the brain, and that these activation patterns are similar to those induced by digits paw's movements. These findings may

  13. RTTN mutations link primary cilia function to organization of the human cerebral cortex

    NARCIS (Netherlands)

    S.K. Kia; E. Verbeek (Elly); M.P. Engelen (Erik); R. Schot (Rachel); R.A. Poot (Raymond); I.F.M. de Coo (René); M. Leguin (Maarten); C.J. Poulton (Cathryn); F. Pourfarzad, F. (Farzin); F.G. Grosveld (Frank); A. Brehm (António); M.C.Y. de Wit (Marie Claire); R. Oegema (Renske); W.B. Dobyns (William); F.W. Verheijen (Frans); G.M.S. Mancini (Grazia)

    2012-01-01

    textabstractPolymicrogyria is a malformation of the developing cerebral cortex caused by abnormal organization and characterized by many small gyri and fusion of the outer molecular layer. We have identified autosomal-recessive mutations in RTTN, encoding Rotatin, in individuals with bilateral

  14. Changes in thickness and surface area of the human cortex and their relationship with intelligence.

    Science.gov (United States)

    Schnack, Hugo G; van Haren, Neeltje E M; Brouwer, Rachel M; Evans, Alan; Durston, Sarah; Boomsma, Dorret I; Kahn, René S; Hulshoff Pol, Hilleke E

    2015-06-01

    Changes in cortical thickness over time have been related to intelligence, but whether changes in cortical surface area are related to general cognitive functioning is unknown. We therefore examined the relationship between intelligence quotient (IQ) and changes in cortical thickness and surface over time in 504 healthy subjects. At 10 years of age, more intelligent children have a slightly thinner cortex than children with a lower IQ. This relationship becomes more pronounced with increasing age: with higher IQ, a faster thinning of the cortex is found over time. In the more intelligent young adults, this relationship reverses so that by the age of 42 a thicker cortex is associated with higher intelligence. In contrast, cortical surface is larger in more intelligent children at the age of 10. The cortical surface is still expanding, reaching its maximum area during adolescence. With higher IQ, cortical expansion is completed at a younger age; and once completed, surface area decreases at a higher rate. These findings suggest that intelligence may be more related to the magnitude and timing of changes in brain structure during development than to brain structure per se, and that the cortex is never completed but shows continuing intelligence-dependent development. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  15. Large-scale remapping of visual cortex is absent in adult humans with macular degeneration

    NARCIS (Netherlands)

    Baseler, Heidi A.; Gouws, Andre; Haak, Koen V.; Racey, Christopher; Crossland, Michael D.; Tufail, Adnan; Rubin, Gary S.; Cornelissen, Frans W.; Morland, Antony B.

    The occipital lobe contains retinotopic representations of the visual field. The representation of the central retina in early visual areas (V1-3) is found at the occipital pole. When the central retina is lesioned in both eyes by macular degeneration, this region of visual cortex at the occipital

  16. Oxygen consumption and blood flow coupling in human motor cortex during intense finger tapping

    DEFF Research Database (Denmark)

    Seyedi Vafaee, Manouchehr; Vang, Kim; Bergersen, Linda H

    2012-01-01

    Rates of cerebral blood flow (CBF) and glucose consumption (CMR(glc)) rise in cerebral cortex during continuous stimulation, while the oxygen-glucose index (OGI) declines as an index of mismatched coupling of oxygen consumption (cerebral metabolic rate of oxygen-CMRO(2)) to CBF and CMR(glc). To t...

  17. Long lasting effects of daily theta burst rTMS sessions in the human amblyopic cortex.

    Science.gov (United States)

    Clavagnier, Simon; Thompson, Benjamin; Hess, Robert F

    2013-11-01

    It has been reported that a single session of 1 Hz or 10 Hz repetitive transcranial magnetic stimulation (rTMS) of the visual cortex can temporarily improve contrast sensitivity in adults with amblyopia. More recently, continuous theta burst stimulation (cTBS) of the visual cortex has been found to improve contrast sensitivity in observers with normal vision. The aims of this study were to assess whether cTBS of the visual cortex could improve contrast sensitivity in adults with amblyopia and whether repeated sessions of cTBS would lead to more pronounced and/or longer lasting effects. cTBS was delivered to the visual cortex while patients viewed a high contrast stimulus with their non-amblyopic eye. This manipulation was designed to bias the effects of cTBS toward inputs from the amblyopic eye. Contrast sensitivity was measured before and after stimulation. The effects of one cTBS session were measured in five patients and the effects of five consecutive daily sessions were measured in four patients. Three patients were available for follow-up at varying intervals after the final session. cTBS improved amblyopic eye contrast sensitivity to high spatial frequencies (P enduring visual function improvements in adults with amblyopia. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Automated immunohistochemical method to analyze large areas of the human cortex.

    Science.gov (United States)

    Abbass, Mohamad; Trought, Kathleen; Long, David; Semechko, Anton; Wong, Albert H C

    2018-01-15

    There have been inconsistencies in the histological abnormalities found in the cerebral cortex from patients with schizophrenia, bipolar disorder and major depression. Discrepancies in previously published reports may arise from small sample sizes, inconsistent methodology and biased cell counting. We applied automated quantification of neuron density, neuron size and cortical layer thickness in large regions of the cerebral cortex in psychiatric patients. This method accurately segments DAPI positive cells that are also stained with CUX2 and FEZF2. Cortical layer thickness, neuron density and neuron size were automatically computed for each cortical layer in numerous Brodmann areas. We did not find pronounced cytoarchitectural abnormalities in the anterior cingulate cortex or orbitofrontal cortex in patients with schizophrenia, bipolar disorder or major depressive disorder. There were no significant differences in layer thickness measured in immunohistochemically stained slides compared with traditional Nissl stained slides. Automated cell counts were correlated, reliable and consistent with manual counts, while being much less time-consuming. We demonstrate the validity of using a novel automated analysis approach to post-mortem brain tissue. We were able to analyze large cortical areas and quantify specific cell populations using immunohistochemical markers. Future analyses could benefit from efficient automated analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Representation of auditory-filter phase characteristics in the cortex of human listeners

    DEFF Research Database (Denmark)

    Rupp, A.; Sieroka, N.; Gutschalk, A.

    2008-01-01

    consistent with the perceptual data obtained with the same stimuli and with results from simulations of neural activity at the output of cochlear preprocessing. These findings demonstrate that phase effects in peripheral auditory processing are accurately reflected up to the level of the auditory cortex....

  20. Category Selectivity of Human Visual Cortex in Perception of Rubin Face–Vase Illusion

    Directory of Open Access Journals (Sweden)

    Xiaogang Wang

    2017-09-01

    Full Text Available When viewing the Rubin face–vase illusion, our conscious perception spontaneously alternates between the face and the vase; this illusion has been widely used to explore bistable perception. Previous functional magnetic resonance imaging (fMRI studies have studied the neural mechanisms underlying bistable perception through univariate and multivariate pattern analyses; however, no studies have investigated the issue of category selectivity. Here, we used fMRI to investigate the neural mechanisms underlying the Rubin face–vase illusion by introducing univariate amplitude and multivariate pattern analyses. The results from the amplitude analysis suggested that the activity in the fusiform face area was likely related to the subjective face perception. Furthermore, the pattern analysis results showed that the early visual cortex (EVC and the face-selective cortex could discriminate the activity patterns of the face and vase perceptions. However, further analysis of the activity patterns showed that only the face-selective cortex contains the face information. These findings indicated that although the EVC and face-selective cortex activities could discriminate the visual information, only the activity and activity pattern in the face-selective areas contained the category information of face perception in the Rubin face–vase illusion.

  1. Toward an autonomous brain machine interface: integrating sensorimotor reward modulation and reinforcement learning.

    Science.gov (United States)

    Marsh, Brandi T; Tarigoppula, Venkata S Aditya; Chen, Chen; Francis, Joseph T

    2015-05-13

    For decades, neurophysiologists have worked on elucidating the function of the cortical sensorimotor control system from the standpoint of kinematics or dynamics. Recently, computational neuroscientists have developed models that can emulate changes seen in the primary motor cortex during learning. However, these simulations rely on the existence of a reward-like signal in the primary sensorimotor cortex. Reward modulation of the primary sensorimotor cortex has yet to be characterized at the level of neural units. Here we demonstrate that single units/multiunits and local field potentials in the primary motor (M1) cortex of nonhuman primates (Macaca radiata) are modulated by reward expectation during reaching movements and that this modulation is present even while subjects passively view cursor motions that are predictive of either reward or nonreward. After establishing this reward modulation, we set out to determine whether we could correctly classify rewarding versus nonrewarding trials, on a moment-to-moment basis. This reward information could then be used in collaboration with reinforcement learning principles toward an autonomous brain-machine interface. The autonomous brain-machine interface would use M1 for both decoding movement intention and extraction of reward expectation information as evaluative feedback, which would then update the decoding algorithm as necessary. In the work presented here, we show that this, in theory, is possible. Copyright © 2015 the authors 0270-6474/15/357374-14$15.00/0.

  2. The Thalamocortical Projection Systems in Primate: An Anatomical Support for Multisensory and Sensorimotor Interplay

    Science.gov (United States)

    Cappe, Céline; Morel, Anne; Barone, Pascal

    2009-01-01

    Multisensory and sensorimotor integrations are usually considered to occur in superior colliculus and cerebral cortex, but few studies proposed the thalamus as being involved in these integrative processes. We investigated whether the organization of the thalamocortical (TC) systems for different modalities partly overlap, representing an anatomical support for multisensory and sensorimotor interplay in thalamus. In 2 macaque monkeys, 6 neuroanatomical tracers were injected in the rostral and caudal auditory cortex, posterior parietal cortex (PE/PEa in area 5), and dorsal and ventral premotor cortical areas (PMd, PMv), demonstrating the existence of overlapping territories of thalamic projections to areas of different modalities (sensory and motor). TC projections, distinct from the ones arising from specific unimodal sensory nuclei, were observed from motor thalamus to PE/PEa or auditory cortex and from sensory thalamus to PMd/PMv. The central lateral nucleus and the mediodorsal nucleus project to all injected areas, but the most significant overlap across modalities was found in the medial pulvinar nucleus. The present results demonstrate the presence of thalamic territories integrating different sensory modalities with motor attributes. Based on the divergent/convergent pattern of TC and corticothalamic projections, 4 distinct mechanisms of multisensory and sensorimotor interplay are proposed. PMID:19150924

  3. The negative ultraslow potential, electrophysiological correlate of infarction in the human cortex.

    Science.gov (United States)

    Lückl, Janos; Lemale, Coline L; Kola, Vasilis; Horst, Viktor; Khojasteh, Uldus; Oliveira-Ferreira, Ana I; Major, Sebastian; Winkler, Maren K L; Kang, Eun-Jeung; Schoknecht, Karl; Martus, Peter; Hartings, Jed A; Woitzik, Johannes; Dreier, Jens P

    2018-06-01

    shift of spreading depolarizations in less compromised tissue. Using Generalized Estimating Equations applied to a logistic regression model, we found that negative ultraslow potential displaying electrodes were significantly more likely to overlie a developing ischaemic lesion (90.0%, 27/30) than those not displaying a negative ultraslow potential (0.0%, 0/20) (P = 0.004). Based on serial neuroimages, the lesions under the electrodes developed within a time window of 72 (56, 134) h. The negative ultraslow potential occurred in this time window in 9/10 patients. It was often preceded by a spreading depolarization cluster with increasingly persistent spreading depressions and progressively prolonged DC shifts and spreading ischaemias. During the negative ultraslow potential, spreading ischaemia lasted for 40.0 (28.0, 76.5) min, cerebral blood flow fell from 57 (53, 65) % to 26 (16, 42) % (n = 4) and tissue partial pressure of oxygen from 12.5 (9.2, 15.2) to 3.3 (2.4, 7.4) mmHg (n = 5). Our data suggest that the negative ultraslow potential is the electrophysiological correlate of infarction in human cerebral cortex and a neuromonitoring-detected medical emergency.awy102media15775596049001.

  4. Modulation of sensorimotor circuits during retrieval of negative Autobiographical Memories: Exploring the impact of personality dimensions.

    Science.gov (United States)

    Mineo, Ludovico; Concerto, Carmen; Patel, Dhaval; Mayorga, Tyrone; Chusid, Eileen; Infortuna, Carmenrita; Aguglia, Eugenio; Sarraf, Yasmin; Battaglia, Fortunato

    2018-02-01

    Autobiographical Memory (AM) retrieval refers to recollection of experienced past events. Previous Transcranial Magnetic Stimulation (TMS) studies have shown that presentation of emotional negative stimuli affects human motor cortex excitability resulting in larger motor evoked potentials (MEPs). Up to date no TMS studies have been carried out in order to investigate the effect of personal memories with negative emotional value on corticospinal excitability. In this study we hypothesized that negative AM retrieval will modulate corticomotor excitability and sensorimotor integration as determined by TMS neurophysiological parameters. Furthermore, we investigated whether TMS responses during retrieval of negative AM are associated with specific personality traits. Twelve healthy subjects were asked to recall either a negative or a neutral AM across two different days in a randomized order. During this memory retrieval, the following TMS parameters were recorded: MEPs; Short- interval intracortical inhibition (SICI) and Intracortical facilitation (ICF); Short-latency afferent inhibition (SAI) and Long- latency afferent inhibition (LAI). Personality traits were assessed by using the Big Five scale. Statistical analysis was performed using factorial ANOVAs and multiple linear regression models. When compared to retrieval of neutral AM, recollection of negative AM induced a larger increase in MEP amplitude, an increase in ICF, and a decrease in SAI. The neuroticism personality trait was a significant predictor of the MEP amplitude increase during retrieval of negative AM. Altogether these results indicate that cortical excitability and sensorimotor integration are selectively modulated by the valence of AM. These results provide the first TMS evidence that the modulatory effect of the AM retrieval is associated with specific personality traits. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Effects of diazepam and levodopa single doses on motor cortex plasticity modulation in healthy human subjects: A TMS study

    Directory of Open Access Journals (Sweden)

    Ilić Nela V.

    2012-01-01

    Full Text Available Introduction. Administration of pharmacological agents with specific actions on neurotransmitter systems is a powerful driver of functional cortical reorganization. Plastic reorganization of the motor cortex in humans studies by the use of non-invasive stimulation protocols, which mimic the Hebbian model of associative plasticity. Objective. Aiming to explore pharmacological modulation on human motor cortex plasticity, we tested healthy subjects after each dosage of diazepam, levodopa i placebo administration, using paired associative stimulation protocol (PAS that induce fenomena similar to a long-term potentiation and depression, as defined on the synaptic level. Methods. We analyzed effects of benzodiazepines (10 mg, levodopa (200 mg and placebo on PAS protocol in 14 healthy volunteers, using a double-blind placebo-controlled study design. PAS consisted of electrical stimuli pairs at n.medianus and magnetic pulses over the scalp (transcranial magnetic stimulation in precisely defined intervals (ISI was 10 and 25 ms for a total of about 15 minutes (200 pairs. MEP amplitudes before and after (0, 10, 20 and 30 minutes later interventional protocols were compared. Results. When protocols were applied with placebo depending on ISI (10 ms - inhibitory, 25 ms - facilitatory effects, MEP amplitudes decreased or increased, while values in the postinterventional period (0, 10, 20 and 30 min were compared with initial values before the use of SAS. The use of benzodiazepines caused the occlusion of LTP-like effect, in contrast to amplification effects recorded after the administration of levodopa. With respect to the LTD-like protocol, the reverse was true (ANOVA for repeat measurements p<0.001. Conclusion. Administration of GABA-ergic agonist diazepam interferes with the induction of associative plasticity in the motor cortex of healthy individuals, as opposed to the use of levodopa, which stimulates these processes. The observed effects point at a

  6. A word expressing affective pain activates the anterior cingulate cortex in the human brain: an fMRI study.

    Science.gov (United States)

    Osaka, Naoyuki; Osaka, Mariko; Morishita, Masanao; Kondo, Hirohito; Fukuyama, Hidenao

    2004-08-12

    We present an fMRI study demonstrating that an onomatopoeia word highly suggestive of subjective pain, heard by the ear, significantly activates the anterior cingulate cortex (ACC) while hearing non-sense words that did not imply affective pain under the same task does not activate this area in humans. We concluded that the ACC would be a pivotal locus for perceiving affective pain evoked by an onomatopoeia word that implied affective pain closely associated with the unpleasantness of pain. We suggest that the pain affect sustained by pain unpleasantness may depend on ACC-prefrontal cortical interactions that modify cognitive evaluation of emotions associated with word-induced pain.

  7. Sensitivity to the visual field origin of natural image patches in human low-level visual cortex

    Directory of Open Access Journals (Sweden)

    Damien J. Mannion

    2015-06-01

    Full Text Available Asymmetries in the response to visual patterns in the upper and lower visual fields (above and below the centre of gaze have been associated with ecological factors relating to the structure of typical visual environments. Here, we investigated whether the content of the upper and lower visual field representations in low-level regions of human visual cortex are specialised for visual patterns that arise from the upper and lower visual fields in natural images. We presented image patches, drawn from above or below the centre of gaze of an observer navigating a natural environment, to either the upper or lower visual fields of human participants (n = 7 while we used functional magnetic resonance imaging (fMRI to measure the magnitude of evoked activity in the visual areas V1, V2, and V3. We found a significant interaction between the presentation location (upper or lower visual field and the image patch source location (above or below fixation; the responses to lower visual field presentation were significantly greater for image patches sourced from below than above fixation, while the responses in the upper visual field were not significantly different for image patches sourced from above and below fixation. This finding demonstrates an association between the representation of the lower visual field in human visual cortex and the structure of the visual input that is likely to be encountered below the centre of gaze.

  8. [Retinotopic mapping of the human visual cortex with functional magnetic resonance imaging - basic principles, current developments and ophthalmological perspectives].

    Science.gov (United States)

    Hoffmann, M B; Kaule, F; Grzeschik, R; Behrens-Baumann, W; Wolynski, B

    2011-07-01

    Since its initial introduction in the mid-1990 s, retinotopic mapping of the human visual cortex, based on functional magnetic resonance imaging (fMRI), has contributed greatly to our understanding of the human visual system. Multiple cortical visual field representations have been demonstrated and thus numerous visual areas identified. The organisation of specific areas has been detailed and the impact of pathophysiologies of the visual system on the cortical organisation uncovered. These results are based on investigations at a magnetic field strength of 3 Tesla or less. In a field-strength comparison between 3 and 7 Tesla, it was demonstrated that retinotopic mapping benefits from a magnetic field strength of 7 Tesla. Specifically, the visual areas can be mapped with high spatial resolution for a detailed analysis of the visual field maps. Applications of fMRI-based retinotopic mapping in ophthalmological research hold promise to further our understanding of plasticity in the human visual cortex. This is highlighted by pioneering studies in patients with macular dysfunction or misrouted optic nerves. © Georg Thieme Verlag KG Stuttgart · New York.

  9. Neuropsychiatric effects of neurodegeneration of the medial vs. lateral ventral prefrontal cortex in humans

    OpenAIRE

    Huey, Edward D.; Lee, Seonjoo; Brickman, Adam M.; Manoochehri, Masood; Griffith, Erica; Devanand, D.P.; Stern, Yaakov; Grafman, Jordan

    2015-01-01

    Animal evidence suggests that a brain network involving the medial and rostral ventral prefrontal cortex (PFC) is central for threat response and arousal and a network involving the lateral and caudal PFC plays an important role in reward learning and behavioral control. In this study, we contrasted the neuropsychiatric effects of degeneration of the medial versus lateral PFC in 43 patients with Frontotemporal dementia and 11 patients with Corticobasal Syndrome using MRI, the Neuropsychiatric...

  10. Basic level category structure emerges gradually across human ventral visual cortex.

    Science.gov (United States)

    Iordan, Marius Cătălin; Greene, Michelle R; Beck, Diane M; Fei-Fei, Li

    2015-07-01

    Objects can be simultaneously categorized at multiple levels of specificity ranging from very broad ("natural object") to very distinct ("Mr. Woof"), with a mid-level of generality (basic level: "dog") often providing the most cognitively useful distinction between categories. It is unknown, however, how this hierarchical representation is achieved in the brain. Using multivoxel pattern analyses, we examined how well each taxonomic level (superordinate, basic, and subordinate) of real-world object categories is represented across occipitotemporal cortex. We found that, although in early visual cortex objects are best represented at the subordinate level (an effect mostly driven by low-level feature overlap between objects in the same category), this advantage diminishes compared to the basic level as we move up the visual hierarchy, disappearing in object-selective regions of occipitotemporal cortex. This pattern stems from a combined increase in within-category similarity (category cohesion) and between-category dissimilarity (category distinctiveness) of neural activity patterns at the basic level, relative to both subordinate and superordinate levels, suggesting that successive visual areas may be optimizing basic level representations.

  11. Sustained selective attention to competing amplitude-modulations in human auditory cortex.

    Science.gov (United States)

    Riecke, Lars; Scharke, Wolfgang; Valente, Giancarlo; Gutschalk, Alexander

    2014-01-01

    Auditory selective attention plays an essential role for identifying sounds of interest in a scene, but the neural underpinnings are still incompletely understood. Recent findings demonstrate that neural activity that is time-locked to a particular amplitude-modulation (AM) is enhanced in the auditory cortex when the modulated stream of sounds is selectively attended to under sensory competition with other streams. However, the target sounds used in the previous studies differed not only in their AM, but also in other sound features, such as carrier frequency or location. Thus, it remains uncertain whether the observed enhancements reflect AM-selective attention. The present study aims at dissociating the effect of AM frequency on response enhancement in auditory cortex by using an ongoing auditory stimulus that contains two competing targets differing exclusively in their AM frequency. Electroencephalography results showed a sustained response enhancement for auditory attention compared to visual attention, but not for AM-selective attention (attended AM frequency vs. ignored AM frequency). In contrast, the response to the ignored AM frequency was enhanced, although a brief trend toward response enhancement occurred during the initial 15 s. Together with the previous findings, these observations indicate that selective enhancement of attended AMs in auditory cortex is adaptive under sustained AM-selective attention. This finding has implications for our understanding of cortical mechanisms for feature-based attentional gain control.

  12. Sustained Selective Attention to Competing Amplitude-Modulations in Human Auditory Cortex

    Science.gov (United States)

    Riecke, Lars; Scharke, Wolfgang; Valente, Giancarlo; Gutschalk, Alexander

    2014-01-01

    Auditory selective attention plays an essential role for identifying sounds of interest in a scene, but the neural underpinnings are still incompletely understood. Recent findings demonstrate that neural activity that is time-locked to a particular amplitude-modulation (AM) is enhanced in the auditory cortex when the modulated stream of sounds is selectively attended to under sensory competition with other streams. However, the target sounds used in the previous studies differed not only in their AM, but also in other sound features, such as carrier frequency or location. Thus, it remains uncertain whether the observed enhancements reflect AM-selective attention. The present study aims at dissociating the effect of AM frequency on response enhancement in auditory cortex by using an ongoing auditory stimulus that contains two competing targets differing exclusively in their AM frequency. Electroencephalography results showed a sustained response enhancement for auditory attention compared to visual attention, but not for AM-selective attention (attended AM frequency vs. ignored AM frequency). In contrast, the response to the ignored AM frequency was enhanced, although a brief trend toward response enhancement occurred during the initial 15 s. Together with the previous findings, these observations indicate that selective enhancement of attended AMs in auditory cortex is adaptive under sustained AM-selective attention. This finding has implications for our understanding of cortical mechanisms for feature-based attentional gain control. PMID:25259525

  13. Effects of Increasing Neuromuscular Electrical Stimulation Current Intensity on Cortical Sensorimotor Network Activation: A Time Domain fNIRS Study.

    Directory of Open Access Journals (Sweden)

    Makii Muthalib

    Full Text Available Neuroimaging studies have shown neuromuscular electrical stimulation (NMES-evoked movements activate regions of the cortical sensorimotor network, including the primary sensorimotor cortex (SMC, premotor cortex (PMC, supplementary motor area (SMA, and secondary somatosensory area (S2, as well as regions of the prefrontal cortex (PFC known to be involved in pain processing. The aim of this study, on nine healthy subjects, was to compare the cortical network activation profile and pain ratings during NMES of the right forearm wrist extensor muscles at increasing current intensities up to and slightly over the individual maximal tolerated intensity (MTI, and with reference to voluntary (VOL wrist extension movements. By exploiting the capability of the multi-channel time domain functional near-infrared spectroscopy technique to relate depth information to the photon time-of-flight, the cortical and superficial oxygenated (O2Hb and deoxygenated (HHb hemoglobin concentrations were estimated. The O2Hb and HHb maps obtained using the General Linear Model (NIRS-SPM analysis method, showed that the VOL and NMES-evoked movements significantly increased activation (i.e., increase in O2Hb and corresponding decrease in HHb in the cortical layer of the contralateral sensorimotor network (SMC, PMC/SMA, and S2. However, the level and area of contralateral sensorimotor network (including PFC activation was significantly greater for NMES than VOL. Furthermore, there was greater bilateral sensorimotor network activation with the high NMES current intensities which corresponded with increased pain ratings. In conclusion, our findings suggest that greater bilateral sensorimotor network activation profile with high NMES current intensities could be in part attributable to increased attentional/pain processing and to increased bilateral sensorimotor integration in these cortical regions.

  14. Effects of Increasing Neuromuscular Electrical Stimulation Current Intensity on Cortical Sensorimotor Network Activation: A Time Domain fNIRS Study.

    Science.gov (United States)

    Muthalib, Makii; Re, Rebecca; Zucchelli, Lucia; Perrey, Stephane; Contini, Davide; Caffini, Matteo; Spinelli, Lorenzo; Kerr, Graham; Quaresima, Valentina; Ferrari, Marco; Torricelli, Alessandro

    2015-01-01

    Neuroimaging studies have shown neuromuscular electrical stimulation (NMES)-evoked movements activate regions of the cortical sensorimotor network, including the primary sensorimotor cortex (SMC), premotor cortex (PMC), supplementary motor area (SMA), and secondary somatosensory area (S2), as well as regions of the prefrontal cortex (PFC) known to be involved in pain processing. The aim of this study, on nine healthy subjects, was to compare the cortical network activation profile and pain ratings during NMES of the right forearm wrist extensor muscles at increasing current intensities up to and slightly over the individual maximal tolerated intensity (MTI), and with reference to voluntary (VOL) wrist extension movements. By exploiting the capability of the multi-channel time domain functional near-infrared spectroscopy technique to relate depth information to the photon time-of-flight, the cortical and superficial oxygenated (O2Hb) and deoxygenated (HHb) hemoglobin concentrations were estimated. The O2Hb and HHb maps obtained using the General Linear Model (NIRS-SPM) analysis method, showed that the VOL and NMES-evoked movements significantly increased activation (i.e., increase in O2Hb and corresponding decrease in HHb) in the cortical layer of the contralateral sensorimotor network (SMC, PMC/SMA, and S2). However, the level and area of contralateral sensorimotor network (including PFC) activation was significantly greater for NMES than VOL. Furthermore, there was greater bilateral sensorimotor network activation with the high NMES current intensities which corresponded with increased pain ratings. In conclusion, our findings suggest that greater bilateral sensorimotor network activation profile with high NMES current intensities could be in part attributable to increased attentional/pain processing and to increased bilateral sensorimotor integration in these cortical regions.

  15. Augmentation of Sensorimotor Adaptability Using Stochastic Resonance Technologies

    Data.gov (United States)

    National Aeronautics and Space Administration — Astronauts experience sensorimotor dysfunction during adaption to g-transitions that occur when entering and exiting microgravity. These sensorimotor disturbances...

  16. Non-concomitant cortical structural and functional alterations in sensorimotor areas following incomplete spinal cord injury

    Directory of Open Access Journals (Sweden)

    Yu Pan

    2017-01-01

    Full Text Available Brain plasticity, including anatomical changes and functional reorganization, is the physiological basis of functional recovery after spinal cord injury (SCI. The correlation between brain anatomical changes and functional reorganization after SCI is unclear. This study aimed to explore whether alterations of cortical structure and network function are concomitant in sensorimotor areas after incomplete SCI. Eighteen patients with incomplete SCI (mean age 40.94 ± 14.10 years old; male:female, 7:11 and 18 healthy subjects (37.33 ± 11.79 years old; male:female, 7:11 were studied by resting state functional magnetic resonance imaging. Gray matter volume (GMV and functional connectivity were used to evaluate cortical structure and network function, respectively. There was no significant alteration of GMV in sensorimotor areas in patients with incomplete SCI compared with healthy subjects. Intra-hemispheric functional connectivity between left primary somatosensory cortex (BA1 and left primary motor cortex (BA4, and left BA1 and left somatosensory association cortex (BA5 was decreased, as well as inter-hemispheric functional connectivity between left BA1 and right BA4, left BA1 and right BA5, and left BA4 and right BA5 in patients with SCI. Functional connectivity between both BA4 areas was also decreased. The decreased functional connectivity between the left BA1 and the right BA4 positively correlated with American Spinal Injury Association sensory score in SCI patients. The results indicate that alterations of cortical anatomical structure and network functional connectivity in sensorimotor areas were non-concomitant in patients with incomplete SCI, indicating the network functional changes in sensorimotor areas may not be dependent on anatomic structure. The strength of functional connectivity within sensorimotor areas could serve as a potential imaging biomarker for assessment and prediction of sensory function in patients with incomplete SCI

  17. Fetal Origin of Sensorimotor Behavior

    Directory of Open Access Journals (Sweden)

    Jaqueline Fagard

    2018-05-01

    Full Text Available The aim of this article is to track the fetal origin of infants’ sensorimotor behavior. We consider development as the self-organizing emergence of complex forms from spontaneously generated activity, governed by the innate capacity to detect and memorize the consequences of spontaneous activity (contingencies, and constrained by the sensory and motor maturation of the body. In support of this view, we show how observations on fetuses and also several fetal experiments suggest that the fetus’s first motor activity allows it to feel the space around it and to feel its body and the consequences of its movements on its body. This primitive motor babbling gives way progressively to sensorimotor behavior which already possesses most of the characteristics of infants’ later behavior: repetition of actions leading to sensations, intentionality, some motor control and oriented reactions to sensory stimulation. In this way the fetus can start developing a body map and acquiring knowledge of its limited physical and social environment.

  18. Transfer of learned perception of sensorimotor simultaneity.

    Science.gov (United States)

    Pesavento, Michael J; Schlag, John

    2006-10-01

    Synchronizing a motor response to a predictable sensory stimulus, like a periodic flash or click, relies on feedback (somesthetic, auditory, visual, or other) from the motor response. Practically, this results in a small (<50 ms) asynchrony in which the motor response leads the sensory event. Here we show that the perceived simultaneity in a coincidence-anticipation task (line crossing) is affected by changing the perceived simultaneity in a different task (pacing). In the pace task, human subjects were instructed to press a key in perfect synchrony with a red square flashed every second. In training sessions, feedback was provided by flashing a blue square with each key press, below the red square. There were two types of training pace sessions: one in which the feedback was provided with no delay, the other (adapting), in which the feedback was progressively delayed (up to 100 ms). Subjects' asynchrony was unchanged in the first case, but it was significantly increased in the pace task with delay. In the coincidence-anticipation task, a horizontally moving vertical bar crossed a vertical line in the middle of a screen. Subjects were instructed to press a key exactly when the bar crossed the line. They were given no feedback on their performance. Asynchrony on the line-crossing task was tested after the training pace task with feedback. We found that this asynchrony to be significantly increased even though there never was any feedback on the coincidence-anticipation task itself. Subjects were not aware that their sensorimotor asynchrony had been lengthened (sometimes doubled). We conclude that perception of simultaneity in a sensorimotor task is learned. If this perception is caused by coincidence of signals in the brain, the timing of these signals depends on something-acquired by experience-more adaptable than physiological latencies.

  19. The impact of top-down spatial attention on laterality and hemispheric asymmetry in the human parietal cortex.

    Science.gov (United States)

    Jeong, Su Keun; Xu, Yaoda

    2016-08-01

    The human parietal cortex exhibits a preference to contralaterally presented visual stimuli (i.e., laterality) as well as an asymmetry between the two hemispheres with the left parietal cortex showing greater laterality than the right. Using visual short-term memory and perceptual tasks and varying target location predictability, this study examined whether hemispheric laterality and asymmetry are fixed characteristics of the human parietal cortex or whether they are dynamic and modulated by the deployment of top-down attention to the target present hemifield. Two parietal regions were examined here that have previously been shown to be involved in visual object individuation and identification and are located in the inferior and superior intraparietal sulcus (IPS), respectively. Across three experiments, significant laterality was found in both parietal regions regardless of attentional modulation with laterality being greater in the inferior than superior IPS, consistent with their roles in object individuation and identification, respectively. Although the deployment of top-down attention had no effect on the superior IPS, it significantly increased laterality in the inferior IPS. The deployment of top-down spatial attention can thus amplify the strength of laterality in the inferior IPS. Hemispheric asymmetry, on the other hand, was absent in both brain regions and only emerged in the inferior but not the superior IPS with the deployment of top-down attention. Interestingly, the strength of hemispheric asymmetry significantly correlated with the strength of laterality in the inferior IPS. Hemispheric asymmetry thus seems to only emerge when there is a sufficient amount of laterality present in a brain region.

  20. Neuronal density, size and shape in the human anterior cingulate cortex: a comparison of Nissl and NeuN staining.

    Science.gov (United States)

    Gittins, Rebecca; Harrison, Paul J

    2004-03-15

    There are an increasing number of quantitative morphometric studies of the human cerebral cortex, especially as part of comparative investigations of major psychiatric disorders. In this context, the present study had two aims. First, to provide quantitative data regarding key neuronal morphometric parameters in the anterior cingulate cortex. Second, to compare the results of conventional Nissl staining with those observed after immunostaining with NeuN, an antibody becoming widely used as a selective neuronal marker. We stained adjacent sections of area 24b from 16 adult brains with cresyl violet or NeuN. We measured the density of pyramidal and non-pyramidal neurons, and the size and shape of pyramidal neurons, in laminae II, III, Va, Vb and VI, using two-dimensional counting methods. Strong correlations between the two modes of staining were seen for all variables. However, NeuN gave slightly higher estimates of neuronal density and size, and a more circular perikaryal shape. Brain pH was correlated with neuronal size, measured with both methods, and with neuronal shape. Age and post-mortem interval showed no correlations with any parameter. These data confirm the value of NeuN as a tool for quantitative neuronal morphometric studies in routinely processed human brain tissue. Absolute values are highly correlated between NeuN and cresyl violet stains, but cannot be interchanged. NeuN may be particularly useful when it is important to distinguish small neurons from glia, such as in cytoarchitectural studies of the cerebral cortex in depression and schizophrenia.

  1. Mina: A Sensorimotor Robotic Orthosis for Mobility Assistance

    OpenAIRE

    Raj, Anil K.; Neuhaus, Peter D.; Moucheboeuf, Adrien M.; Noorden, Jerryll H.; Lecoutre, David V.

    2011-01-01

    While most mobility options for persons with paraplegia or paraparesis employ wheeled solutions, significant adverse health, psychological, and social consequences result from wheelchair confinement. Modern robotic exoskeleton devices for gait assistance and rehabilitation, however, can support legged locomotion systems for those with lower extremity weakness or paralysis. The Florida Institute for Human and Machine Cognition (IHMC) has developed the Mina, a prototype sensorimotor robotic ort...

  2. Sensorimotor learning and the ontogeny of the mirror neuron system

    OpenAIRE

    Catmur, C

    2013-01-01

    Mirror neurons, which have now been found in the human and songbird as well as the macaque, respond to both the observation and the performance of the same action. It has been suggested that their matching response properties have evolved as an adaptation for action understanding; alternatively, these properties may arise through sensorimotor experience. Here I review mirror neuron response characteristics from the perspective of ontogeny; I discuss the limited evidence for mirror neurons in ...

  3. Glutamate concentration in the medial prefrontal cortex predicts resting-state cortical-subcortical functional connectivity in humans.

    Directory of Open Access Journals (Sweden)

    Niall W Duncan

    Full Text Available Communication between cortical and subcortical regions is integral to a wide range of psychological processes and has been implicated in a number of psychiatric conditions. Studies in animals have provided insight into the biochemical and connectivity processes underlying such communication. However, to date no experiments that link these factors in humans in vivo have been carried out. To investigate the role of glutamate in individual differences in communication between the cortex--specifically the medial prefrontal cortex (mPFC--and subcortical regions in humans, a combination of resting-state fMRI, DTI and MRS was performed. The subcortical target regions were the nucleus accumbens (NAc, dorsomedial thalamus (DMT, and periaqueductal grey (PAG. It was found that functional connectivity between the mPFC and each of the NAc and DMT was positively correlated with mPFC glutamate concentrations, whilst functional connectivity between the mPFC and PAG was negatively correlated with glutamate concentration. The correlations involving mPFC glutamate and FC between the mPFC and each of the DMT and PAG were mirrored by correlations with structural connectivity, providing evidence that the glutamatergic relationship may, in part, be due to direct connectivity. These results are in agreement with existing results from animal studies and may have relevance for MDD and schizophrenia.

  4. Feature diagnosticity and task context shape activity in human scene-selective cortex.

    Science.gov (United States)

    Lowe, Matthew X; Gallivan, Jason P; Ferber, Susanne; Cant, Jonathan S

    2016-01-15

    Scenes are constructed from multiple visual features, yet previous research investigating scene processing has often focused on the contributions of single features in isolation. In the real world, features rarely exist independently of one another and likely converge to inform scene identity in unique ways. Here, we utilize fMRI and pattern classification techniques to examine the interactions between task context (i.e., attend to diagnostic global scene features; texture or layout) and high-level scene attributes (content and spatial boundary) to test the novel hypothesis that scene-selective cortex represents multiple visual features, the importance of which varies according to their diagnostic relevance across scene categories and task demands. Our results show for the first time that scene representations are driven by interactions between multiple visual features and high-level scene attributes. Specifically, univariate analysis of scene-selective cortex revealed that task context and feature diagnosticity shape activity differentially across scene categories. Examination using multivariate decoding methods revealed results consistent with univariate findings, but also evidence for an interaction between high-level scene attributes and diagnostic visual features within scene categories. Critically, these findings suggest visual feature representations are not distributed uniformly across scene categories but are shaped by task context and feature diagnosticity. Thus, we propose that scene-selective cortex constructs a flexible representation of the environment by integrating multiple diagnostically relevant visual features, the nature of which varies according to the particular scene being perceived and the goals of the observer. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Neural sources of visual working memory maintenance in human parietal and ventral extrastriate visual cortex.

    Science.gov (United States)

    Becke, Andreas; Müller, Notger; Vellage, Anne; Schoenfeld, Mircea Ariel; Hopf, Jens-Max

    2015-04-15

    Maintaining information in visual working memory is reliably indexed by the contralateral delay activity (CDA) - a sustained modulation of the event-related potential (ERP) with a topographical maximum over posterior scalp regions contralateral to the memorized input. Based on scalp topography, it is hypothesized that the CDA reflects neural activity in the parietal cortex, but the precise cortical origin of underlying electric activity was never determined. Here we combine ERP recordings with magnetoencephalography based source localization to characterize the cortical current sources generating the CDA. Observers performed a cued delayed match to sample task where either the color or the relative position of colored dots had to be maintained in memory. A detailed source-localization analysis of the magnetic activity in the retention interval revealed that the magnetic analog of the CDA (mCDA) is generated by current sources in the parietal cortex. Importantly, we find that the mCDA also receives contribution from current sources in the ventral extrastriate cortex that display a time-course similar to the parietal sources. On the basis of the magnetic responses, forward modeling of ERP data reveals that the ventral sources have non-optimal projections and that these sources are therefore concealed in the ERP by overlapping fields with parietal projections. The present observations indicate that visual working memory maintenance, as indexed by the CDA, involves the parietal cortical regions as well as the ventral extrastriate regions, which code the sensory representation of the memorized content. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Distributed neural signatures of natural audiovisual speech and music in the human auditory cortex.

    Science.gov (United States)

    Salmi, Juha; Koistinen, Olli-Pekka; Glerean, Enrico; Jylänki, Pasi; Vehtari, Aki; Jääskeläinen, Iiro P; Mäkelä, Sasu; Nummenmaa, Lauri; Nummi-Kuisma, Katarina; Nummi, Ilari; Sams, Mikko

    2017-08-15

    During a conversation or when listening to music, auditory and visual information are combined automatically into audiovisual objects. However, it is still poorly understood how specific type of visual information shapes neural processing of sounds in lifelike stimulus environments. Here we applied multi-voxel pattern analysis to investigate how naturally matching visual input modulates supratemporal cortex activity during processing of naturalistic acoustic speech, singing and instrumental music. Bayesian logistic regression classifiers with sparsity-promoting priors were trained to predict whether the stimulus was audiovisual or auditory, and whether it contained piano playing, speech, or singing. The predictive performances of the classifiers were tested by leaving one participant at a time for testing and training the model using the remaining 15 participants. The signature patterns associated with unimodal auditory stimuli encompassed distributed locations mostly in the middle and superior temporal gyrus (STG/MTG). A pattern regression analysis, based on a continuous acoustic model, revealed that activity in some of these MTG and STG areas were associated with acoustic features present in speech and music stimuli. Concurrent visual stimulus modulated activity in bilateral MTG (speech), lateral aspect of right anterior STG (singing), and bilateral parietal opercular cortex (piano). Our results suggest that specific supratemporal brain areas are involved in processing complex natural speech, singing, and piano playing, and other brain areas located in anterior (facial speech) and posterior (music-related hand actions) supratemporal cortex are influenced by related visual information. Those anterior and posterior supratemporal areas have been linked to stimulus identification and sensory-motor integration, respectively. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Top-down modulation in human visual cortex predicts the stability of a perceptual illusion

    Science.gov (United States)

    Meindertsma, Thomas; Hillebrand, Arjan; van Dijk, Bob W.; Lamme, Victor A. F.; Donner, Tobias H.

    2014-01-01

    Conscious perception sometimes fluctuates strongly, even when the sensory input is constant. For example, in motion-induced blindness (MIB), a salient visual target surrounded by a moving pattern suddenly disappears from perception, only to reappear after some variable time. Whereas such changes of perception result from fluctuations of neural activity, mounting evidence suggests that the perceptual changes, in turn, may also cause modulations of activity in several brain areas, including visual cortex. In this study, we asked whether these latter modulations might affect the subsequent dynamics of perception. We used magnetoencephalography (MEG) to measure modulations in cortical population activity during MIB. We observed a transient, retinotopically widespread modulation of beta (12–30 Hz)-frequency power over visual cortex that was closely linked to the time of subjects' behavioral report of the target disappearance. This beta modulation was a top-down signal, decoupled from both the physical stimulus properties and the motor response but contingent on the behavioral relevance of the perceptual change. Critically, the modulation amplitude predicted the duration of the subsequent target disappearance. We propose that the transformation of the perceptual change into a report triggers a top-down mechanism that stabilizes the newly selected perceptual interpretation. PMID:25411458

  8. Sensitivity of human auditory cortex to rapid frequency modulation revealed by multivariate representational similarity analysis.

    Science.gov (United States)

    Joanisse, Marc F; DeSouza, Diedre D

    2014-01-01

    Functional Magnetic Resonance Imaging (fMRI) was used to investigate the extent, magnitude, and pattern of brain activity in response to rapid frequency-modulated sounds. We examined this by manipulating the direction (rise vs. fall) and the rate (fast vs. slow) of the apparent pitch of iterated rippled noise (IRN) bursts. Acoustic parameters were selected to capture features used in phoneme contrasts, however the stimuli themselves were not perceived as speech per se. Participants were scanned as they passively listened to sounds in an event-related paradigm. Univariate analyses revealed a greater level and extent of activation in bilateral auditory cortex in response to frequency-modulated sweeps compared to steady-state sounds. This effect was stronger in the left hemisphere. However, no regions showed selectivity for either rate or direction of frequency modulation. In contrast, multivoxel pattern analysis (MVPA) revealed feature-specific encoding for direction of modulation in auditory cortex bilaterally. Moreover, this effect was strongest when analyses were restricted to anatomical regions lying outside Heschl's gyrus. We found no support for feature-specific encoding of frequency modulation rate. Differential findings of modulation rate and direction of modulation are discussed with respect to their relevance to phonetic discrimination.

  9. Mirth and laughter elicited by electrical stimulation of the human anterior cingulate cortex.

    Science.gov (United States)

    Caruana, Fausto; Avanzini, Pietro; Gozzo, Francesca; Francione, Stefano; Cardinale, Francesco; Rizzolatti, Giacomo

    2015-10-01

    Laughter is a complex motor behavior that, typically, expresses mirth. Despite its fundamental role in social life, knowledge about the neural basis of laughter is very limited and mostly based on a few electrical stimulation (ES) studies carried out in epileptic patients. In these studies laughter was elicited from temporal areas where it was accompanied by mirth and from frontal areas plus an anterior cingulate case where laughter without mirth was observed. On the basis of these findings, it has been proposed a dichotomy between temporal lobe areas processing the emotional content of laughter and anterior cingulate cortex (ACC) and motor areas responsible of laughter production. The present study is aimed to understand the role of ACC in laughter. We report the effects of stimulation of 10 rostral, pregenual ACC (pACC) patients in which the ES elicited laughter. In half of the patients ES elicited a clear burst of laughter with mirth, while in the other half mirth was not evident. This large dataset allow us to offer a more reliable picture of the functional contribute of this region in laughter, and to precisely localize it in the cingulate cortex. We conclude that the pACC is involved in both the motor and the affective components of emotions, and challenge the validity of a sharp dichotomy between motor and emotional centers for laughing. Finally, we suggest a possible anatomical network for the production of positive emotional expressions. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Neuroplasticity Changes on Human Motor Cortex Induced by Acupuncture Therapy: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Yi Yang

    2017-01-01

    Full Text Available While neuroplasticity changes measured by transcranial magnetic stimulation have been proved to be highly correlated to motor recovery and have been tested in various forms of interventions, it has not been applied to investigate the neurophysiologic mechanism of acupuncture therapy. The aim of this study is to investigate neuroplasticity changes induced by a single session of acupuncture therapy in healthy adults, regarding the excitability change on bilateral primary motor cortex and interhemispheric inhibition. Ten subjects took a 30-minute acupuncture therapy and the same length relaxing phase in separate days. Transcranial magnetic stimulation measures, including resting motor threshold, amplitudes of motor-evoked potential, and interhemispheric inhibition, were assessed before and 10 minutes after intervention. Acupuncture treatment showed significant changes on potential amplitude from both ipsilateral and contralateral hemispheres to acupuncture compared to baseline. Also, interhemispheric inhibition from the contralateral motor cortex to the opposite showed a significant decline. The results indicated that corticomotoneuronal excitability and interhemispheric competition could be modulated by acupuncture therapy on healthy subjects. The following question about whether these changes will be observed in the same way on stroke patients and whether they correlate with the therapeutic effect on movement need to be answered by following studies. This trial is registered with ISRCTN13074245.

  11. Sensorimotor Functional and Structural Networks after Intracerebral Stem Cell Grafts in the Ischemic Mouse Brain.

    Science.gov (United States)

    Green, Claudia; Minassian, Anuka; Vogel, Stefanie; Diedenhofen, Michael; Beyrau, Andreas; Wiedermann, Dirk; Hoehn, Mathias

    2018-02-14

    Past investigations on stem cell-mediated recovery after stroke have limited their focus on the extent and morphological development of the ischemic lesion itself over time or on the integration capacity of the stem cell graft ex vivo However, an assessment of the long-term functional and structural improvement in vivo is essential to reliably quantify the regenerative capacity of cell implantation after stroke. We induced ischemic stroke in nude mice and implanted human neural stem cells (H9 derived) into the ipsilateral cortex in the acute phase. Functional and structural connectivity changes of the sensorimotor network were noninvasively monitored using magnetic resonance imaging for 3 months after stem cell implantation. A sharp decrease of the functional sensorimotor network extended even to the contralateral hemisphere, persisting for the whole 12 weeks of observation. In mice with stem cell implantation, functional networks were stabilized early on, pointing to a paracrine effect as an early supportive mechanism of the graft. This stabilization required the persistent vitality of the stem cells, monitored by bioluminescence imaging. Thus, we also observed deterioration of the early network stabilization upon vitality loss of the graft after a few weeks. Structural connectivity analysis showed fiber-density increases between the cortex and white matter regions occurring predominantly on the ischemic hemisphere. These fiber-density changes were nearly the same for both study groups. This motivated us to hypothesize that the stem cells can influence, via early paracrine effect, the functional networks, while observed structural changes are mainly stimulated by the ischemic event. SIGNIFICANCE STATEMENT In recent years, research on strokes has made a shift away from a focus on immediate ischemic effects and towards an emphasis on the long-range effects of the lesion on the whole brain. Outcome improvements in stem cell therapies also require the understanding of

  12. Sensorimotor learning and the ontogeny of the mirror neuron system.

    Science.gov (United States)

    Catmur, Caroline

    2013-04-12

    Mirror neurons, which have now been found in the human and songbird as well as the macaque, respond to both the observation and the performance of the same action. It has been suggested that their matching response properties have evolved as an adaptation for action understanding; alternatively, these properties may arise through sensorimotor experience. Here I review mirror neuron response characteristics from the perspective of ontogeny; I discuss the limited evidence for mirror neurons in early development; and I describe the growing body of evidence suggesting that mirror neuron responses can be modified through experience, and that sensorimotor experience is the critical type of experience for producing mirror neuron responses. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  13. The physiological basis of the effects of intermittent theta burst stimulation of the human motor cortex.

    Science.gov (United States)

    Di Lazzaro, V; Pilato, F; Dileone, M; Profice, P; Oliviero, A; Mazzone, P; Insola, A; Ranieri, F; Meglio, M; Tonali, P A; Rothwell, J C

    2008-08-15

    Theta burst stimulation (TBS) is a form of repetitive transcranial magnetic stimulation (TMS). When applied to motor cortex it leads to after-effects on corticospinal and corticocortical excitability that may reflect LTP/LTD-like synaptic effects. An inhibitory form of TBS (continuous, cTBS) suppresses MEPs, and spinal epidural recordings show this is due to suppression of the I1 volley evoked by TMS. Here we investigate whether the excitatory form of TBS (intermittent, iTBS) affects the same I-wave circuitry. We recorded corticospinal volleys evoked by single pulse TMS of the motor cortex before and after iTBS in three conscious patients who had an electrode implanted in the cervical epidural space for the control of pain. As in healthy subjects, iTBS increased MEPs, and this was accompanied by a significant increase in the amplitude of later I-waves, but not the I1 wave. In two of the patients we tested the excitability of the contralateral cortex and found a significant suppression of the late I-waves. The extent of the changes varied between the three patients, as did their age. To investigate whether age might be a significant contributor to the variability we examined the effect of iTBS on MEPs in 18 healthy subjects. iTBS facilitated MEPs evoked by TMS of the conditioned hemisphere and suppressed MEPs evoked by stimulation of the contralateral hemisphere. There was a slight but non-significant decline in MEP facilitation with age, suggesting that interindividual variability was more important than age in explaining our data. In a subgroup of 10 subjects we found that iTBS had no effect on the duration of the ipsilateral silent period suggesting that the reduction in contralateral MEPs was not due to an increase in ongoing transcallosal inhibition. In conclusion, iTBS affects the excitability of excitatory synaptic inputs to pyramidal tract neurones that are recruited by a TMS pulse, both in the stimulated hemisphere and in the contralateral hemisphere

  14. Can you hear me yet? An intracranial investigation of speech and non-speech audiovisual interactions in human cortex.

    Science.gov (United States)

    Rhone, Ariane E; Nourski, Kirill V; Oya, Hiroyuki; Kawasaki, Hiroto; Howard, Matthew A; McMurray, Bob

    In everyday conversation, viewing a talker's face can provide information about the timing and content of an upcoming speech signal, resulting in improved intelligibility. Using electrocorticography, we tested whether human auditory cortex in Heschl's gyrus (HG) and on superior temporal gyrus (STG) and motor cortex on precentral gyrus (PreC) were responsive to visual/gestural information prior to the onset of sound and whether early stages of auditory processing were sensitive to the visual content (speech syllable versus non-speech motion). Event-related band power (ERBP) in the high gamma band was content-specific prior to acoustic onset on STG and PreC, and ERBP in the beta band differed in all three areas. Following sound onset, we found with no evidence for content-specificity in HG, evidence for visual specificity in PreC, and specificity for both modalities in STG. These results support models of audio-visual processing in which sensory information is integrated in non-primary cortical areas.

  15. Distribution of precursor amyloid-β-protein messenger RNA in human cerebral cortex: relationship to neurofibrillary tangles and neuritic plaques

    International Nuclear Information System (INIS)

    Lewis, D.A.; Higgins, G.A.; Young, W.G.; Goldgaber, D.; Gajdusek, D.C.; Wilson, M.C.; Morrison, J.H.

    1988-01-01

    Neurofibrillary tangles (NFT) and neuritic plaques (NP), two neuropathological markers of Alzheimer disease, may both contain peptide fragments derived from the human amyloid β protein. However, the nature of the relationship between NFT and NP and the source of the amyloid β proteins found in each have remained unclear. The authors used in situ hybridization techniques to map the anatomical distribution of precursor amyloid-β-protein mRNA in the neocortex of brains from three subjects with no known neurologic disease and from five patients with Alzheimer disease. In brains from control subjects, positively hybridizing neurons were present in cortical regions and layers that contain a high density of neuropathological markers in Alzheimer disease, as well as in those loci that contain NP but few NFT. Quantitative analyses of in situ hybridization patterns within layers III and V of the superior frontal cortex revealed that the presence of high numbers of NFT in Alzheimer-diseased brains was associated with a decrease in the number of positively hybridizing neurons compared to controls and Alzheimer-diseased brains with few NFT. These findings suggest that the expression of precursor amyloid-β-protein mRNA may be a necessary but is clearly not a sufficient prerequisite for NFT formation. In addition, these results may indicate that the amyloid β protein, present in NP in a given region or layer of cortex, is not derived from the resident neuronal cell bodies that express the mRNA for the precursor protein

  16. Regional structural differences across functionally parcellated Brodmann areas of human primary somatosensory cortex.

    Science.gov (United States)

    Sánchez-Panchuelo, Rosa-María; Besle, Julien; Mougin, Olivier; Gowland, Penny; Bowtell, Richard; Schluppeck, Denis; Francis, Susan

    2014-06-01

    Ultra-high-field (UHF) MRI is ideally suited for structural and functional imaging of the brain. High-resolution structural MRI can be used to map the anatomical boundaries between functional domains of the brain by identifying changes related to the pattern of myelination within cortical gray matter, opening up the possibility to study the relationship between functional domains and underlying structure in vivo. In a recent study, we demonstrated the correspondence between functional (based on retinotopic mapping) and structural (based on changes in T2(⁎)-weighted images linked to myelination) parcellations of the primary visual cortex (V1) in vivo at 7T (Sanchez-Panchuelo et al., 2012b). Here, we take advantage of the improved BOLD CNR and high spatial resolution achievable at 7T to study regional structural variations across the functionally defined areas within the primary somatosensory cortex (S1) in individual subjects. Using a traveling wave fMRI paradigm to map the internal somatotopic representation of the index, middle, and ring fingers in S1, we were able to identify multiple map reversals at the tip and base, corresponding to the boundaries between Brodmann areas 3a, 3b, 1 and 2. Based on high resolution structural MRI data acquired in the same subjects, we inspected these functionally-parcellated Brodmann areas for differences in cortical thickness and MR contrast measures (magnetization transfer ratio (MTR) and signal intensity in phase sensitive inversion recovery (PSIR) images) that are sensitive to myelination. Consistent area-related differences in cortical thickness and MTR/PSIR measurements were found across subjects. However these measures did not have sufficient sensitivity to allow definition of areal boundaries. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. Experiments in robotic sensorimotor control during grasp

    International Nuclear Information System (INIS)

    Stansfield, S.A.

    1993-01-01

    A series of experiments is presented, using a robot manipulator, which attempt to reproduce human sensorimotor control during grasping. The work utilizes a multifingered, dexterous robot hand equipped with a fingertip force sensor to explore dynamic grasp force adjustment during manipulation. The work is primarily concerned with the relationship between the weight of an object and the grasp force required to lift it. Too weak a grasp is unstable and the object will slip from the hand. Too strong a grasp may damage the object and/or the manipulator. An algorithm is presented which reproduces observed human behavior during grasp-and-lift tasks. The algorithm uses tactile information from the sensor to dynamically adjust the grasp force during lift. It is assumed that there is no a priori knowledge about the object to be manipulated. The effects of different arm/hand postures and object surfaces is explored. Finally, the use of sensory data to detect unexpected object motion and to signal transitions between manipulation phases--with the coincident triggering of new motor programs--is investigated

  18. The Effects of Long Duration Bed Rest as a Spaceflight Analogue on Resting State Sensorimotor Network Functional Connectivity and Neurocognitive Performance

    Science.gov (United States)

    Cassady, K.; Koppelmans, V.; Yuan, P.; Cooke, K.; De Dios, Y.; Stepanyan, V.; Szecsy, D.; Gadd, N.; Wood, S.; Reuter-Lorenz, P.; hide

    2015-01-01

    Long duration spaceflight has been associated with detrimental alterations in human sensorimotor systems and neurocognitive performance. Prolonged exposure to a head-down tilt position during long duration bed rest can resemble several effects of the microgravity environment such as reduced sensory inputs, body unloading and increased cephalic fluid distribution. The question of whether microgravity affects other central nervous system functions such as brain functional connectivity and its relationship with neurocognitive performance is largely unknown, but of potential importance to the health and performance of astronauts both during and post-flight. The aims of the present study are 1) to identify changes in sensorimotor resting state functional connectivity that occur with extended bed rest exposure, and to characterize their recovery time course; 2) to evaluate how these neural changes correlate with neurocognitive performance. Resting-state functional magnetic resonance imaging (rsfMRI) data were collected from 17 male participants. The data were acquired through the NASA bed rest facility, located at the University of Texas Medical Branch (Galveston, TX). Participants remained in bed with their heads tilted down six degrees below their feet for 70 consecutive days. RsfMRI data were obtained at seven time points: 7 and 12 days before bed rest; 7, 50, and 65 days during bed rest; and 7 and 12 days after bed rest. Functional connectivity magnetic resonance imaging (fcMRI) analysis was performed to measure the connectivity of sensorimotor networks in the brain before, during, and post-bed rest. We found a decrease in left putamen connectivity with the pre- and post-central gyri from pre bed rest to the last day in bed rest. In addition, vestibular cortex connectivity with the posterior cingulate cortex decreased from pre to post bed rest. Furthermore, connectivity between cerebellar right superior posterior fissure and other cerebellar regions decreased from

  19. Sensorimotor learning in Dab1(scm) (scrambler) mutant mice.

    Science.gov (United States)

    Lalonde, R; Strazielle, C

    2011-04-15

    Homozygous Dab1(scm) mouse mutants with cell ectopias in cerebellar cortex and neocortex were compared with non-ataxic controls on two tests of motor coordination: rotorod and grid climbing. Even at the minimal speed of 4 rpm and unlike controls, none of the Dab1(scm) mutants reached criterion on the constant speed rotorod. In contrast, Dab1(scm) mutants improved their performances on the vertical grid over the course of the same number of trials. Thus, despite massive cerebellar degeneration, sensorimotor learning for equilibrium is still possible, indicating the potential usefulness of the grid-climbing test in determining residual functions in mice with massive cerebellar damage. Copyright © 2010. Published by Elsevier B.V.

  20. Evidence of impaired brain activity balance after passive sensorimotor stimulation in multiple sclerosis.

    Directory of Open Access Journals (Sweden)

    Nikolaos Petsas

    Full Text Available OBJECTIVES: Examination of sensorimotor activation alone in multiple sclerosis (MS patients may not yield a comprehensive view of cerebral response to task stimulation. Additional information may be obtained by examining the negative BOLD response (deactivation. Aim of this work was to characterize activation and deactivation patterns during passive hand movements in MS patients. METHODS: 13 relapsing remitting-MS patients (RRMS, 18 secondary progressive-MS patients (SPMS and 15 healthy controls (HC underwent an fMRI study during passive right-hand movements. Activation and deactivation contrasts in the three groups were entered into ANOVA, age and gender corrected. Post-hoc analysis was performed with one-sample and two-sample t-tests. For each patient we obtained lesion volume (LV from both T1- and T2-weighted images. RESULTS: Activations showed a progressive extension to the ipsilateral brain hemisphere according to the group and the clinical form (HCsensorimotor areas was reduced in both patient groups with respect to HC. Deactivation of posterior cortical areas belonging to the default mode network (DMN, was increased in RRMS, but not in SPMS, with respect to HC. The amount of activation in the contralateral sensorimotor cortex was significantly correlated with that of deactivation in the DMN in HC and RRMS, but not in SPMS. Both increased activation and decreased deactivation patterns correlated with LV. CONCLUSION: In RRMS patients, increased cortical activation was associated with increased deactivation of the posterior cortex suggesting a greater resting-state activity in the DMN, probably aimed at facilitating sensorimotor circuit engagement during task performance. In SPMS the coupling between increased sensorimotor activation/increased DMN deactivation was not observed suggesting disorganization between anticorrelated functional networks as a consequence of a higher

  1. Mapping the after-effects of theta burst stimulation on the human auditory cortex with functional imaging.

    Science.gov (United States)

    Andoh, Jamila; Zatorre, Robert J

    2012-09-12

    Auditory cortex pertains to the processing of sound, which is at the basis of speech or music-related processing. However, despite considerable recent progress, the functional properties and lateralization of the human auditory cortex are far from being fully understood. Transcranial Magnetic Stimulation (TMS) is a non-invasive technique that can transiently or lastingly modulate cortical excitability via the application of localized magnetic field pulses, and represents a unique method of exploring plasticity and connectivity. It has only recently begun to be applied to understand auditory cortical function. An important issue in using TMS is that the physiological consequences of the stimulation are difficult to establish. Although many TMS studies make the implicit assumption that the area targeted by the coil is the area affected, this need not be the case, particularly for complex cognitive functions which depend on interactions across many brain regions. One solution to this problem is to combine TMS with functional Magnetic resonance imaging (fMRI). The idea here is that fMRI will provide an index of changes in brain activity associated with TMS. Thus, fMRI would give an independent means of assessing which areas are affected by TMS and how they are modulated. In addition, fMRI allows the assessment of functional connectivity, which represents a measure of the temporal coupling between distant regions. It can thus be useful not only to measure the net activity modulation induced by TMS in given locations, but also the degree to which the network properties are affected by TMS, via any observed changes in functional connectivity. Different approaches exist to combine TMS and functional imaging according to the temporal order of the methods. Functional MRI can be applied before, during, after, or both before and after TMS. Recently, some studies interleaved TMS and fMRI in order to provide online mapping of the functional changes induced by TMS. However, this

  2. Vocal Tract Images Reveal Neural Representations of Sensorimotor Transformation During Speech Imitation

    Science.gov (United States)

    Carey, Daniel; Miquel, Marc E.; Evans, Bronwen G.; Adank, Patti; McGettigan, Carolyn

    2017-01-01

    Abstract Imitating speech necessitates the transformation from sensory targets to vocal tract motor output, yet little is known about the representational basis of this process in the human brain. Here, we address this question by using real-time MR imaging (rtMRI) of the vocal tract and functional MRI (fMRI) of the brain in a speech imitation paradigm. Participants trained on imitating a native vowel and a similar nonnative vowel that required lip rounding. Later, participants imitated these vowels and an untrained vowel pair during separate fMRI and rtMRI runs. Univariate fMRI analyses revealed that regions including left inferior frontal gyrus were more active during sensorimotor transformation (ST) and production of nonnative vowels, compared with native vowels; further, ST for nonnative vowels activated somatomotor cortex bilaterally, compared with ST of native vowels. Using test representational similarity analysis (RSA) models constructed from participants’ vocal tract images and from stimulus formant distances, we found that RSA searchlight analyses of fMRI data showed either type of model could be represented in somatomotor, temporal, cerebellar, and hippocampal neural activation patterns during ST. We thus provide the first evidence of widespread and robust cortical and subcortical neural representation of vocal tract and/or formant parameters, during prearticulatory ST. PMID:28334401

  3. Sensorimotor gating deficits in multiple system atrophy

    DEFF Research Database (Denmark)

    Zoetmulder, Marielle; Biernat, Heidi Bryde; Nikolic, Miki

    2014-01-01

    Prepulse inhibition (PPI) of the auditory blink reflex is a measure of sensorimotor gating, which reflects an organism's ability to filter out irrelevant sensory information. PPI has never been studied in patients with multiple system atrophy (MSA), although sensorimotor deficits are frequently a...... associated with synucleinopathies. We investigated whether alterations in PPI were more pronounced in MSA compared with Parkinson's disease (PD), idiopathic rapid eye movement sleep behavior disorder (iRBD) and healthy controls....

  4. Music-induced cortical plasticity and lateral inhibition in the human auditory cortex as foundations for tonal tinnitus treatment.

    Science.gov (United States)

    Pantev, Christo; Okamoto, Hidehiko; Teismann, Henning

    2012-01-01

    Over the past 15 years, we have studied plasticity in the human auditory cortex by means of magnetoencephalography (MEG). Two main topics nurtured our curiosity: the effects of musical training on plasticity in the auditory system, and the effects of lateral inhibition. One of our plasticity studies found that listening to notched music for 3 h inhibited the neuronal activity in the auditory cortex that corresponded to the center-frequency of the notch, suggesting suppression of neural activity by lateral inhibition. Subsequent research on this topic found that suppression was notably dependent upon the notch width employed, that the lower notch-edge induced stronger attenuation of neural activity than the higher notch-edge, and that auditory focused attention strengthened the inhibitory networks. Crucially, the overall effects of lateral inhibition on human auditory cortical activity were stronger than the habituation effects. Based on these results we developed a novel treatment strategy for tonal tinnitus-tailor-made notched music training (TMNMT). By notching the music energy spectrum around the individual tinnitus frequency, we intended to attract lateral inhibition to auditory neurons involved in tinnitus perception. So far, the training strategy has been evaluated in two studies. The results of the initial long-term controlled study (12 months) supported the validity of the treatment concept: subjective tinnitus loudness and annoyance were significantly reduced after TMNMT but not when notching spared the tinnitus frequencies. Correspondingly, tinnitus-related auditory evoked fields (AEFs) were significantly reduced after training. The subsequent short-term (5 days) training study indicated that training was more effective in the case of tinnitus frequencies ≤ 8 kHz compared to tinnitus frequencies >8 kHz, and that training should be employed over a long-term in order to induce more persistent effects. Further development and evaluation of TMNMT therapy

  5. Music-induced cortical plasticity and lateral inhibition in the human auditory cortex as foundations for tonal tinnitus treatment

    Directory of Open Access Journals (Sweden)

    Christo ePantev

    2012-06-01

    Full Text Available Over the past 15 years, we have studied plasticity in the human auditory cortex by means of magnetoencephalography (MEG. Two main topics nurtured our curiosity: the effects of musical training on plasticity in the auditory system, and the effects of lateral inhibition. One of our plasticity studies found that listening to notched music for three hours inhibited the neuronal activity in the auditory cortex that corresponded to the center-frequency of the notch, suggesting suppression of neural activity by lateral inhibition. Crucially, the overall effects of lateral inhibition on human auditory cortical activity were stronger than the habituation effects. Based on these results we developed a novel treatment strategy for tonal tinnitus - tailor-made notched music training (TMNMT. By notching the music energy spectrum around the individual tinnitus frequency, we intended to attract lateral inhibition to auditory neurons involved in tinnitus perception. So far, the training strategy has been evaluated in two studies. The results of the initial long-term controlled study (12 months supported the validity of the treatment concept: subjective tinnitus loudness and annoyance were significantly reduced after TMNMT but not when notching spared the tinnitus frequencies. Correspondingly, tinnitus-related auditory evoked fields (AEFs were significantly reduced after training. The subsequent short-term (5 days training study indicated that training was more effective in the case of tinnitus frequencies ≤ 8 kHz compared to tinnitus frequencies > 8 kHz, and that training should be employed over a long-term in order to induce more persistent effects. Further development and evaluation of TMNMT therapy are planned. A goal is to transfer this novel, completely non-invasive, and low-cost treatment approach for tonal tinnitus into routine clinical practice.

  6. Ghrelin mimics fasting to enhance human hedonic, orbitofrontal cortex, and hippocampal responses to food.

    Science.gov (United States)

    Goldstone, Anthony P; Prechtl, Christina G; Scholtz, Samantha; Miras, Alexander D; Chhina, Navpreet; Durighel, Giuliana; Deliran, Seyedeh S; Beckmann, Christian; Ghatei, Mohammad A; Ashby, Damien R; Waldman, Adam D; Gaylinn, Bruce D; Thorner, Michael O; Frost, Gary S; Bloom, Stephen R; Bell, Jimmy D

    2014-06-01

    Ghrelin, which is a stomach-derived hormone, increases with fasting and energy restriction and may influence eating behaviors through brain hedonic reward-cognitive systems. Therefore, changes in plasma ghrelin might mediate counter-regulatory responses to a negative energy balance through changes in food hedonics. We investigated whether ghrelin administration (exogenous hyperghrelinemia) mimics effects of fasting (endogenous hyperghrelinemia) on the hedonic response and activation of brain-reward systems to food. In a crossover design, 22 healthy, nonobese adults (17 men) underwent a functional magnetic resonance imaging (fMRI) food-picture evaluation task after a 16-h overnight fast (Fasted-Saline) or after eating breakfast 95 min before scanning (730 kcal, 14% protein, 31% fat, and 55% carbohydrate) and receiving a saline (Fed-Saline) or acyl ghrelin (Fed-Ghrelin) subcutaneous injection before scanning. One male subject was excluded from the fMRI analysis because of excess head motion, which left 21 subjects with brain-activation data. Compared with the Fed-Saline visit, both ghrelin administration to fed subjects (Fed-Ghrelin) and fasting (Fasted-Saline) significantly increased the appeal of high-energy foods and associated orbitofrontal cortex activation. Both fasting and ghrelin administration also increased hippocampus activation to high-energy- and low-energy-food pictures. These similar effects of endogenous and exogenous hyperghrelinemia were not explicable by consistent changes in glucose, insulin, peptide YY, and glucagon-like peptide-1. Neither ghrelin administration nor fasting had any significant effect on nucleus accumbens, caudate, anterior insula, or amygdala activation during the food-evaluation task or on auditory, motor, or visual cortex activation during a control task. Ghrelin administration and fasting have similar acute stimulatory effects on hedonic responses and the activation of corticolimbic reward-cognitive systems during food

  7. Functional Imaging of Human Vestibular Cortex Activity Elicited by Skull Tap and Auditory Tone Burst

    Science.gov (United States)

    Noohi, Fatemeh; Kinnaird, Catherine; Wood, Scott; Bloomberg, Jacob; Mulavara, Ajitkumar; Seidler, Rachael

    2014-01-01

    The aim of the current study was to characterize the brain activation in response to two modes of vestibular stimulation: skull tap and auditory tone burst. The auditory tone burst has been used in previous studies to elicit saccular Vestibular Evoked Myogenic Potentials (VEMP) (Colebatch & Halmagyi 1992; Colebatch et al. 1994). Some researchers have reported that airconducted skull tap elicits both saccular and utricle VEMPs, while being faster and less irritating for the subjects (Curthoys et al. 2009, Wackym et al., 2012). However, it is not clear whether the skull tap and auditory tone burst elicit the same pattern of cortical activity. Both forms of stimulation target the otolith response, which provides a measurement of vestibular function independent from semicircular canals. This is of high importance for studying the vestibular disorders related to otolith deficits. Previous imaging studies have documented activity in the anterior and posterior insula, superior temporal gyrus, inferior parietal lobule, pre and post central gyri, inferior frontal gyrus, and the anterior cingulate cortex in response to different modes of vestibular stimulation (Bottini et al., 1994; Dieterich et al., 2003; Emri et al., 2003; Schlindwein et al., 2008; Janzen et al., 2008). Here we hypothesized that the skull tap elicits the similar pattern of cortical activity as the auditory tone burst. Subjects put on a set of MR compatible skull tappers and headphones inside the 3T GE scanner, while lying in supine position, with eyes closed. All subjects received both forms of the stimulation, however, the order of stimulation with auditory tone burst and air-conducted skull tap was counterbalanced across subjects. Pneumatically powered skull tappers were placed bilaterally on the cheekbones. The vibration of the cheekbone was transmitted to the vestibular cortex, resulting in vestibular response (Halmagyi et al., 1995). Auditory tone bursts were also delivered for comparison. To validate

  8. Influence of Aripiprazole, Risperidone, and Amisulpride on Sensory and Sensorimotor Gating in Healthy ‘Low and High Gating' Humans and Relation to Psychometry

    Science.gov (United States)

    Csomor, Philipp A; Preller, Katrin H; Geyer, Mark A; Studerus, Erich; Huber, Theodor; Vollenweider, Franz X

    2014-01-01

    Despite advances in the treatment of schizophrenia spectrum disorders with atypical antipsychotics (AAPs), there is still need for compounds with improved efficacy/side-effect ratios. Evidence from challenge studies suggests that the assessment of gating functions in humans and rodents with naturally low-gating levels might be a useful model to screen for novel compounds with antipsychotic properties. To further evaluate and extend this translational approach, three AAPs were examined. Compounds without antipsychotic properties served as negative control treatments. In a placebo-controlled, within-subject design, healthy males received either single doses of aripiprazole and risperidone (n=28), amisulpride and lorazepam (n=30), or modafinil and valproate (n=30), and placebo. Prepulse inhibiton (PPI) and P50 suppression were assessed. Clinically associated symptoms were evaluated using the SCL-90-R. Aripiprazole, risperidone, and amisulpride increased P50 suppression in low P50 gaters. Lorazepam, modafinil, and valproate did not influence P50 suppression in low gaters. Furthermore, low P50 gaters scored significantly higher on the SCL-90-R than high P50 gaters. Aripiprazole increased PPI in low PPI gaters, whereas modafinil and lorazepam attenuated PPI in both groups. Risperidone, amisulpride, and valproate did not influence PPI. P50 suppression in low gaters appears to be an antipsychotic-sensitive neurophysiologic marker. This conclusion is supported by the association of low P50 suppression and higher clinically associated scores. Furthermore, PPI might be sensitive for atypical mechanisms of antipsychotic medication. The translational model investigating differential effects of AAPs on gating in healthy subjects with naturally low gating can be beneficial for phase II/III development plans by providing additional information for critical decision making. PMID:24801767

  9. Influence of position and stimulation parameters on intracortical inhibition and facilitation in human tongue motor cortex

    DEFF Research Database (Denmark)

    Kothari, Mohit; Svensson, Peter; Nielsen, Jørgen Feldbæk

    2014-01-01

    Paired-pulse transcranial magnetic stimulation (ppTMS) can be used to assess short-interval intracortical inhibitory (SICI) and facilitatory (ICF) networks. Many methodological parameters may however influence the outcome. The aim of the study was to examine the influence of body positions (recline...... motor cortex and motor evoked potentials (MEPs) were recorded from contralateral tongue muscles. In study 1, single pulse and three ppTMS ISIs: 2, 10, 15 ms were applied 8 times each in three blocks (TS: 120%, 140% and 160% of resting motor threshold (rMT); CS: 80% of rMT) in two different body...... positions (recline and supine) randomly. In study 2, single pulse and four ppTMS ISIs: 2, 2.5, 3, 3.5 ms were applied 8 times each in randomized order in two blocks (CS: 70% and 80% of rMT; TS: 120% of rMT). There was a significant effect of body position (P=0.049), TS intensities (P

  10. Dynamic Correlations between Intrinsic Connectivity and Extrinsic Connectivity of the Auditory Cortex in Humans.

    Science.gov (United States)

    Cui, Zhuang; Wang, Qian; Gao, Yayue; Wang, Jing; Wang, Mengyang; Teng, Pengfei; Guan, Yuguang; Zhou, Jian; Li, Tianfu; Luan, Guoming; Li, Liang

    2017-01-01

    The arrival of sound signals in the auditory cortex (AC) triggers both local and inter-regional signal propagations over time up to hundreds of milliseconds and builds up both intrinsic functional connectivity (iFC) and extrinsic functional connectivity (eFC) of the AC. However, interactions between iFC and eFC are largely unknown. Using intracranial stereo-electroencephalographic recordings in people with drug-refractory epilepsy, this study mainly investigated the temporal dynamic of the relationships between iFC and eFC of the AC. The results showed that a Gaussian wideband-noise burst markedly elicited potentials in both the AC and numerous higher-order cortical regions outside the AC (non-auditory cortices). Granger causality analyses revealed that in the earlier time window, iFC of the AC was positively correlated with both eFC from the AC to the inferior temporal gyrus and that to the inferior parietal lobule. While in later periods, the iFC of the AC was positively correlated with eFC from the precentral gyrus to the AC and that from the insula to the AC. In conclusion, dual-directional interactions occur between iFC and eFC of the AC at different time windows following the sound stimulation and may form the foundation underlying various central auditory processes, including auditory sensory memory, object formation, integrations between sensory, perceptional, attentional, motor, emotional, and executive processes.

  11. Dynamic Correlations between Intrinsic Connectivity and Extrinsic Connectivity of the Auditory Cortex in Humans

    Directory of Open Access Journals (Sweden)

    Zhuang Cui

    2017-08-01

    Full Text Available The arrival of sound signals in the auditory cortex (AC triggers both local and inter-regional signal propagations over time up to hundreds of milliseconds and builds up both intrinsic functional connectivity (iFC and extrinsic functional connectivity (eFC of the AC. However, interactions between iFC and eFC are largely unknown. Using intracranial stereo-electroencephalographic recordings in people with drug-refractory epilepsy, this study mainly investigated the temporal dynamic of the relationships between iFC and eFC of the AC. The results showed that a Gaussian wideband-noise burst markedly elicited potentials in both the AC and numerous higher-order cortical regions outside the AC (non-auditory cortices. Granger causality analyses revealed that in the earlier time window, iFC of the AC was positively correlated with both eFC from the AC to the inferior temporal gyrus and that to the inferior parietal lobule. While in later periods, the iFC of the AC was positively correlated with eFC from the precentral gyrus to the AC and that from the insula to the AC. In conclusion, dual-directional interactions occur between iFC and eFC of the AC at different time windows following the sound stimulation and may form the foundation underlying various central auditory processes, including auditory sensory memory, object formation, integrations between sensory, perceptional, attentional, motor, emotional, and executive processes.

  12. Mapping face categorization in the human ventral occipitotemporal cortex with direct neural intracranial recordings.

    Science.gov (United States)

    Rossion, Bruno; Jacques, Corentin; Jonas, Jacques

    2018-02-26

    The neural basis of face categorization has been widely investigated with functional magnetic resonance imaging (fMRI), identifying a set of face-selective local regions in the ventral occipitotemporal cortex (VOTC). However, indirect recording of neural activity with fMRI is associated with large fluctuations of signal across regions, often underestimating face-selective responses in the anterior VOTC. While direct recording of neural activity with subdural grids of electrodes (electrocorticography, ECoG) or depth electrodes (stereotactic electroencephalography, SEEG) offers a unique opportunity to fill this gap in knowledge, these studies rather reveal widely distributed face-selective responses. Moreover, intracranial recordings are complicated by interindividual variability in neuroanatomy, ambiguity in definition, and quantification of responses of interest, as well as limited access to sulci with ECoG. Here, we propose to combine SEEG in large samples of individuals with fast periodic visual stimulation to objectively define, quantify, and characterize face categorization across the whole VOTC. This approach reconciles the wide distribution of neural face categorization responses with their (right) hemispheric and regional specialization, and reveals several face-selective regions in anterior VOTC sulci. We outline the challenges of this research program to understand the neural basis of face categorization and high-level visual recognition in general. © 2018 New York Academy of Sciences.

  13. Contralateral white noise selectively changes left human auditory cortex activity in a lexical decision task.

    Science.gov (United States)

    Behne, Nicole; Wendt, Beate; Scheich, Henning; Brechmann, André

    2006-04-01

    In a previous study, we hypothesized that the approach of presenting information-bearing stimuli to one ear and noise to the other ear may be a general strategy to determine hemispheric specialization in auditory cortex (AC). In that study, we confirmed the dominant role of the right AC in directional categorization of frequency modulations by showing that fMRI activation of right but not left AC was sharply emphasized when masking noise was presented to the contralateral ear. Here, we tested this hypothesis using a lexical decision task supposed to be mainly processed in the left hemisphere. Subjects had to distinguish between pseudowords and natural words presented monaurally to the left or right ear either with or without white noise to the other ear. According to our hypothesis, we expected a strong effect of contralateral noise on fMRI activity in left AC. For the control conditions without noise, we found that activation in both auditory cortices was stronger on contralateral than on ipsilateral word stimulation consistent with a more influential contralateral than ipsilateral auditory pathway. Additional presentation of contralateral noise did not significantly change activation in right AC, whereas it led to a significant increase of activation in left AC compared with the condition without noise. This is consistent with a left hemispheric specialization for lexical decisions. Thus our results support the hypothesis that activation by ipsilateral information-bearing stimuli is upregulated mainly in the hemisphere specialized for a given task when noise is presented to the more influential contralateral ear.

  14. Spatial attention improves the quality of population codes in human visual cortex.

    Science.gov (United States)

    Saproo, Sameer; Serences, John T

    2010-08-01

    Selective attention enables sensory input from behaviorally relevant stimuli to be processed in greater detail, so that these stimuli can more accurately influence thoughts, actions, and future goals. Attention has been shown to modulate the spiking activity of single feature-selective neurons that encode basic stimulus properties (color, orientation, etc.). However, the combined output from many such neurons is required to form stable representations of relevant objects and little empirical work has formally investigated the relationship between attentional modulations on population responses and improvements in encoding precision. Here, we used functional MRI and voxel-based feature tuning functions to show that spatial attention induces a multiplicative scaling in orientation-selective population response profiles in early visual cortex. In turn, this multiplicative scaling correlates with an improvement in encoding precision, as evidenced by a concurrent increase in the mutual information between population responses and the orientation of attended stimuli. These data therefore demonstrate how multiplicative scaling of neural responses provides at least one mechanism by which spatial attention may improve the encoding precision of population codes. Increased encoding precision in early visual areas may then enhance the speed and accuracy of perceptual decisions computed by higher-order neural mechanisms.

  15. Peripheral nerve injury induces glial activation in primary motor cortex

    OpenAIRE

    Julieta Troncoso; Julieta Troncoso; Efraín Buriticá; Efraín Buriticá

    2015-01-01

    Preliminary evidence suggests that peripheral facial nerve injuries are associated with sensorimotor cortex reorganization. We have characterized facial nerve lesion-induced structural changes in primary motor cortex layer 5 pyramidal neurons and their relationship with glial cell density using a rodent facial paralysis model. First, we used adult transgenic mice expressing green fluorescent protein in microglia and yellow fluorescent protein in pyramidal neurons which were subjected to eithe...

  16. Dynamical Representation of Dominance Relationships in the Human Rostromedial Prefrontal Cortex

    NARCIS (Netherlands)

    Ligneul, R.V.A.; Obeso, I.; Ruff, C.C.; Dreher, J.C.

    2016-01-01

    Summary Humans and other primates have evolved the ability to represent their status in the group’s social hierarchy, which is essential for avoiding harm and accessing resources. Yet it remains unclear how the human brain learns dominance status and adjusts behavior accordingly during dynamic

  17. Mosaic model for sensorimotor learning and control.

    Science.gov (United States)

    Haruno, M; Wolpert, D M; Kawato, M

    2001-10-01

    Humans demonstrate a remarkable ability to generate accurate and appropriate motor behavior under many different and often uncertain environmental conditions. We previously proposed a new modular architecture, the modular selection and identification for control (MOSAIC) model, for motor learning and control based on multiple pairs of forward (predictor) and inverse (controller) models. The architecture simultaneously learns the multiple inverse models necessary for control as well as how to select the set of inverse models appropriate for a given environment. It combines both feedforward and feedback sensorimotor information so that the controllers can be selected both prior to movement and subsequently during movement. This article extends and evaluates the MOSAIC architecture in the following respects. The learning in the architecture was implemented by both the original gradient-descent method and the expectation-maximization (EM) algorithm. Unlike gradient descent, the newly derived EM algorithm is robust to the initial starting conditions and learning parameters. Second, simulations of an object manipulation task prove that the architecture can learn to manipulate multiple objects and switch between them appropriately. Moreover, after learning, the model shows generalization to novel objects whose dynamics lie within the polyhedra of already learned dynamics. Finally, when each of the dynamics is associated with a particular object shape, the model is able to select the appropriate controller before movement execution. When presented with a novel shape-dynamic pairing, inappropriate activation of modules is observed followed by on-line correction.

  18. Functional Connectivity of Human Chewing

    Science.gov (United States)

    Quintero, A.; Ichesco, E.; Schutt, R.; Myers, C.; Peltier, S.; Gerstner, G.E.

    2013-01-01

    Mastication is one of the most important orofacial functions. The neurobiological mechanisms of masticatory control have been investigated in animal models, but less so in humans. This project used functional connectivity magnetic resonance imaging (fcMRI) to assess the positive temporal correlations among activated brain areas during a gum-chewing task. Twenty-nine healthy young-adults underwent an fcMRI scanning protocol while they chewed gum. Seed-based fcMRI analyses were performed with the motor cortex and cerebellum as regions of interest. Both left and right motor cortices were reciprocally functionally connected and functionally connected with the post-central gyrus, cerebellum, cingulate cortex, and precuneus. The cerebellar seeds showed functional connections with the contralateral cerebellar hemispheres, bilateral sensorimotor cortices, left superior temporal gyrus, and left cingulate cortex. These results are the first to identify functional central networks engaged during mastication. PMID:23355525

  19. Characteristics of high affinity and low affinity adenosine binding sites in human cerebral cortex

    International Nuclear Information System (INIS)

    John, D.; Fox, I.V.

    1986-01-01

    The binding characteristics of human brain cortical membrane fractions were evaluated to test the hypothesis that there are A 1 and A 2 adenosine binding sites. The ligands used were 2-chloro(8- 3 H) adenosine and N 6 -(adenine-2, 8- 3 H) cyclohexayladenosine. Binding of chloroadenosine to human brain cortical membranes was time dependent, reversible and concentration dependent. The kinetic constant determinations from binding studies of the adenosine receptor are presented. Utilizing tritium-cyclohexyladenosine as ligand the authors observed evidence for a high affinity binding site in human brain cortical membranes with a kd of 5 nM

  20. Functional studies of the human auditory cortex, auditory memory and musical hallucinations

    International Nuclear Information System (INIS)

    Goycoolea, Marcos; Mena, Ismael; Neubauer, Sonia

    2004-01-01

    Objectives. 1. To determine which areas of the cerebral cortex are activated stimulating the left ear with pure tones, and what type of stimulation occurs (eg. excitatory or inhibitory) in these different areas. 2. To use this information as an initial step to develop a normal functional data base for future studies. 3. To try to determine if there is a biological substrate to the process of recalling previous auditory perceptions and if possible, suggest a locus for auditory memory. Method. Brain perfusion single photon emission computerized tomography (SPECT) evaluation was conducted: 1-2) Using auditory stimulation with pure tones in 4 volunteers with normal hearing. 3) In a patient with bilateral profound hearing loss who had auditory perception of previous musical experiences; while injected with Tc99m HMPAO while she was having the sensation of hearing a well known melody. Results. Both in the patient with auditory hallucinations and the normal controls -stimulated with pure tones- there was a statistically significant increase in perfusion in Brodmann's area 39, more intense on the right side (right to left p < 0.05). With a lesser intensity there was activation in the adjacent area 40 and there was intense activation also in the executive frontal cortex areas 6, 8, 9, and 10 of Brodmann. There was also activation of area 7 of Brodmann; an audio-visual association area; more marked on the right side in the patient and the normal stimulated controls. In the subcortical structures there was also marked activation in the patient with hallucinations in both lentiform nuclei, thalamus and caudate nuclei also more intense in the right hemisphere, 5, 4.7 and 4.2 S.D. above the mean respectively and 5, 3.3, and 3 S.D. above the normal mean in the left hemisphere respectively. Similar findings were observed in normal controls. Conclusions. After auditory stimulation with pure tones in the left ear of normal female volunteers, there is bilateral activation of area 39

  1. Functional Imaging of Human Vestibular Cortex Activity Elicited by Skull Tap and Auditory Tone Burst

    Science.gov (United States)

    Noohi, F.; Kinnaird, C.; Wood, S.; Bloomberg, J.; Mulavara, A.; Seidler, R.

    2016-01-01

    The current study characterizes brain activation in response to two modes of vestibular stimulation: skull tap and auditory tone burst. The auditory tone burst has been used in previous studies to elicit either the vestibulo-spinal reflex (saccular-mediated colic Vestibular Evoked Myogenic Potentials (cVEMP)), or the ocular muscle response (utricle-mediated ocular VEMP (oVEMP)). Some researchers have reported that air-conducted skull tap elicits both saccular and utricle-mediated VEMPs, while being faster and less irritating for the subjects. However, it is not clear whether the skull tap and auditory tone burst elicit the same pattern of cortical activity. Both forms of stimulation target the otolith response, which provides a measurement of vestibular function independent from semicircular canals. This is of high importance for studying otolith-specific deficits, including gait and balance problems that astronauts experience upon returning to earth. Previous imaging studies have documented activity in the anterior and posterior insula, superior temporal gyrus, inferior parietal lobule, inferior frontal gyrus, and the anterior cingulate cortex in response to different modes of vestibular stimulation. Here we hypothesized that skull taps elicit similar patterns of cortical activity as the auditory tone bursts, and previous vestibular imaging studies. Subjects wore bilateral MR compatible skull tappers and headphones inside the 3T GE scanner, while lying in the supine position, with eyes closed. Subjects received both forms of the stimulation in a counterbalanced fashion. Pneumatically powered skull tappers were placed bilaterally on the cheekbones. The vibration of the cheekbone was transmitted to the vestibular system, resulting in the vestibular cortical response. Auditory tone bursts were also delivered for comparison. To validate our stimulation method, we measured the ocular VEMP outside of the scanner. This measurement showed that both skull tap and auditory

  2. Measurement of neurovascular coupling in human motor cortex using simultaneous transcranial doppler (TCD) and electroencephalography (EEG).

    Science.gov (United States)

    Alam, Monzurul; Ahmed, Ghazanfar; Ling, Yan To; Zheng, Yong-Ping

    2018-05-25

    Event-related desynchronization (ERD) is a relative power decrease of electroencephalogram (EEG) signals in a specific frequency band during physical motor execution, while transcranial Doppler (TCD) measures cerebral blood flow velocity. The objective of this study was to investigate the neurovascular coupling in the motor cortex by using an integrated EEG and TCD system, and to find any difference in hemodynamic responses in healthy young male and female adults. Approach: 30 healthy volunteers, aged 20-30 years were recruited for this study. The subjects were asked to perform a motor task for the duration of a provided visual cue. Simultaneous EEG and TCD recording was carried out using a new integrated system to detect the ERD arising from the EEG signals, and to measure the mean blood flow velocity of the left and right middle cerebral arteries from bilateral TCD signals. Main Results: The results showed a significant decrease in EEG power in mu band (7.5-12.5 Hz) during the motor task compared to the resting phase. It showed significant increase in desynchronization on the contralateral side of the motor task compared to the ipsilateral side. Mean blood flow velocity during the task phase was significantly higher in comparison with the resting phase at the contralateral side. The results also showed a significantly higher increase in the percentage of mean blood flow velocity in the contralateral side of motor task compared to the ipsilateral side. However, no significant difference in desynchronization, or change of mean blood flow velocity was found between males and females. Significance: A combined TCD-EEG system successfully detects ERD and blood flow velocity in cerebral arteries, and can be used as a useful tool to study neurovascular coupling in the brain. There is no significant difference in the hemodynamic responses in healthy young males and females. © 2018 Institute of Physics and Engineering in Medicine.

  3. Variability of in vivo linear microcrack accumulation in the cortex of elderly human ribs

    Directory of Open Access Journals (Sweden)

    Amanda M. Agnew

    2017-06-01

    Full Text Available Excessive accumulation of microdamage in the skeleton in vivo is believed to contribute to fragility and risk of fracture, particularly in the elderly. Current knowledge of how much in vivo damage accrual varies between individuals, if at all, is lacking. In this study, paired sixth ribs from five male and five female elderly individuals (76–92 years, mean age = 84.7 years were examined using en bloc staining and fluorescent microcopy to quantify linear microcracks present at the time of death (i.e. in vivo microdamage. Crack number, crack length, crack density, and crack surface density were measured for each complete cross-section, with densities calculated using the variable of bone area (which accounts for the influence of porosity on the cortex, unlike the more frequently used cortical area, and analyzed using a two-way mixed model analysis of variance. Results indicate that while microcracks between individuals differ significantly, differences between the left and right corresponding pairs within individuals and the pleural and cutaneous cortices within each rib did not. These results suggest that systemic influences, such as differential metabolic activity, affect the accumulation of linear microcracks. Furthermore, variation in remodeling rates between individuals may be a major factor contributing to differential fracture risk in the elderly. Future work should expand to include a wider age range to examine differences in in vivo microdamage accumulation across the lifespan, as well as considering the influence of bisphosphonates on microdamage accumulation in the context of compromised remodeling rates in the elderly.

  4. Affective and cognitive prefrontal cortex projections to the lateral habenula in humans.

    Directory of Open Access Journals (Sweden)

    Karin eVadovičová

    2014-10-01

    Full Text Available Anterior insula (AI and dorsal ACC (dACC are known to process information about pain, loss, adversities, bad, harmful or suboptimal choices and consequences that threaten survival or well-being. Also pregenual ACC (pgACC is linked to loss and pain, being activated by sad thoughts and regrets. Lateral habenula (LHb is stimulated by predicted and received pain, discomfort, aversive outcome, loss. Its chronic stimulation makes us feel worse/low and gradually stops us choosing and moving for the suboptimal or punished choices, by direct and indirect (via rostromedial tegmental nucleus RMTg inhibition of DRN and VTA/SNc. The response selectivity of LHb neurons suggests their cortical input from affective and cognitive evaluative regions that make expectations about bad, unpleasant or suboptimal outcomes. Based on these facts we predicted direct dACC, pgACC and AI projections to LHb, which form part of an adversity processing circuit that learns to avoid bad outcomes by suppressing dopamine and serotonin signal. To test this connectivity we used Diffusion Tensor Imaging (DTI. We found dACC, pgACC, AI and caudolateral OFC projections to LHb. We predicted no corticohabenular projections from the reward processing regions: medial OFC (mOFC and ventral ACC (vACC because both respond most strongly to good, high valued stimuli and outcomes, inducing dopamine and serotonin release. This lack of LHb projections was confirmed for vACC and likely for mOFC. The surprising findings were the corticohabenular projections from the cognitive prefrontal cortex regions, known for flexible reasoning, planning and combining whatever information are relevant for reaching current goals. We propose that the prefrontohabenular projections provide a teaching signal for value-based choice behaviour, to learn to deselect, avoid or inhibit the potentially harmful, low valued or wrong choices, goals, strategies, predictions and ways of doing things, to prevent bad or suboptimal

  5. A combined analysis of genome-wide expression profiling of bipolar disorder in human prefrontal cortex.

    Science.gov (United States)

    Wang, Jinglu; Qu, Susu; Wang, Weixiao; Guo, Liyuan; Zhang, Kunlin; Chang, Suhua; Wang, Jing

    2016-11-01

    Numbers of gene expression profiling studies of bipolar disorder have been published. Besides different array chips and tissues, variety of the data processes in different cohorts aggravated the inconsistency of results of these genome-wide gene expression profiling studies. By searching the gene expression databases, we obtained six data sets for prefrontal cortex (PFC) of bipolar disorder with raw data and combinable platforms. We used standardized pre-processing and quality control procedures to analyze each data set separately and then combined them into a large gene expression matrix with 101 bipolar disorder subjects and 106 controls. A standard linear mixed-effects model was used to calculate the differentially expressed genes (DEGs). Multiple levels of sensitivity analyses and cross validation with genetic data were conducted. Functional and network analyses were carried out on basis of the DEGs. In the result, we identified 198 unique differentially expressed genes in the PFC of bipolar disorder and control. Among them, 115 DEGs were robust to at least three leave-one-out tests or different pre-processing methods; 51 DEGs were validated with genetic association signals. Pathway enrichment analysis showed these DEGs were related with regulation of neurological system, cell death and apoptosis, and several basic binding processes. Protein-protein interaction network further identified one key hub gene. We have contributed the most comprehensive integrated analysis of bipolar disorder expression profiling studies in PFC to date. The DEGs, especially those with multiple validations, may denote a common signature of bipolar disorder and contribute to the pathogenesis of disease. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Imagery of a moving object: the role of occipital cortex and human MT/V5+.

    Science.gov (United States)

    Kaas, Amanda; Weigelt, Sarah; Roebroeck, Alard; Kohler, Axel; Muckli, Lars

    2010-01-01

    Visual imagery--similar to visual perception--activates feature-specific and category-specific visual areas. This is frequently observed in experiments where the instruction is to imagine stimuli that have been shown immediately before the imagery task. Hence, feature-specific activation could be related to the short-term memory retrieval of previously presented sensory information. Here, we investigated mental imagery of stimuli that subjects had not seen before, eliminating the effects of short-term memory. We recorded brain activation using fMRI while subjects performed a behaviourally controlled guided imagery task in predefined retinotopic coordinates to optimize sensitivity in early visual areas. Whole brain analyses revealed activation in a parieto-frontal network and lateral-occipital cortex. Region of interest (ROI) based analyses showed activation in left hMT/V5+. Granger causality mapping taking left hMT/V5+ as source revealed an imagery-specific directed influence from the left inferior parietal lobule (IPL). Interestingly, we observed a negative BOLD response in V1-3 during imagery, modulated by the retinotopic location of the imagined motion trace. Our results indicate that rule-based motion imagery can activate higher-order visual areas involved in motion perception, with a role for top-down directed influences originating in IPL. Lower-order visual areas (V1, V2 and V3) were down-regulated during this type of imagery, possibly reflecting inhibition to avoid visual input from interfering with the imagery construction. This suggests that the activation in early visual areas observed in previous studies might be related to short- or long-term memory retrieval of specific sensory experiences.

  7. Detailed T1-Weighted Profiles from the Human Cortex Measured in Vivo at 3 Tesla MRI.

    Science.gov (United States)

    Ferguson, Bart; Petridou, Natalia; Fracasso, Alessio; van den Heuvel, Martijn P; Brouwer, Rachel M; Hulshoff Pol, Hilleke E; Kahn, René S; Mandl, René C W

    2018-04-01

    Studies into cortical thickness in psychiatric diseases based on T1-weighted MRI frequently report on aberrations in the cerebral cortex. Due to limitations in image resolution for studies conducted at conventional MRI field strengths (e.g. 3 Tesla (T)) this information cannot be used to establish which of the cortical layers may be implicated. Here we propose a new analysis method that computes one high-resolution average cortical profile per brain region extracting myeloarchitectural information from T1-weighted MRI scans that are routinely acquired at a conventional field strength. To assess this new method, we acquired standard T1-weighted scans at 3 T and compared them with state-of-the-art ultra-high resolution T1-weighted scans optimised for intracortical myelin contrast acquired at 7 T. Average cortical profiles were computed for seven different brain regions. Besides a qualitative comparison between the 3 T scans, 7 T scans, and results from literature, we tested if the results from dynamic time warping-based clustering are similar for the cortical profiles computed from 7 T and 3 T data. In addition, we quantitatively compared cortical profiles computed for V1, V2 and V7 for both 7 T and 3 T data using a priori information on their relative myelin concentration. Although qualitative comparisons show that at an individual level average profiles computed for 7 T have more pronounced features than 3 T profiles the results from the quantitative analyses suggest that average cortical profiles computed from T1-weighted scans acquired at 3 T indeed contain myeloarchitectural information similar to profiles computed from the scans acquired at 7 T. The proposed method therefore provides a step forward to study cortical myeloarchitecture in vivo at conventional magnetic field strength both in health and disease.

  8. Stimulus rate dependence of regional cerebral blood flow in human striate cortex, demonstrated by positron emission tomography

    International Nuclear Information System (INIS)

    Fox, P.T.; Raichle, M.E.

    1984-01-01

    The purpose of this investigation was to determine the relationship between the repetition rate of a simple sensory stimulus and regional cerebral blood flow (rCBF) in the human brain. Positron emission tomography (PET), using intravenously administered H 2 ( 15 )O as the diffusible blood-flow tracer, was employed for all CBF measurements. The use of H 2 ( 15 )O with PET allowed eight CBF measurements to be made in rapid sequence under multiple stimulation conditions without removing the subject from the tomograph. Nine normal volunteers each underwent a series of eight H2( 15 )O PET measurements of CBF. Initial and final scans were made during visual deprivation. The six intervening scans were made during visual activation with patterned-flash stimuli given in random order at 1.0-, 3.9-, 7.8-, 15.5-, 33.1-, and 61-Hz repetition rates. The region of greatest rCBF increase was determined. Within this region the rCBF was determined for every test condition and then expressed as the percentage change from the value of the initial unstimulated scan (rCBF% delta). In every subject, striate cortex rCBF% delta varied systematically with stimulus rate. Between 0 and 7.8 Hz, rCBF% delta was a linear function of stimulus repetition rate. The rCBF response peaked at 7.8 Hz and then declined. The rCBF% delta during visual stimulation was significantly greater than that during visual deprivation for every stimulus rate except 1.0 Hz. The anatomical localization of the region of peak rCBF response was determined for every subject to be the mesial occipital lobes along the calcarine fissure, primary visual cortex. Stimulus rate is a significant determinant of rCBF response in the visual cortex. Investigators of brain responses to selective activation procedures should be aware of the potential effects of stimulus rate on rCBF and other measurements of cerebral metabolism

  9. Fetal functional imaging portrays heterogeneous development of emerging human brain networks

    OpenAIRE

    Schwartz, Ernst; Kasprian, Gregor; Gruber, Gerlinde M.; Prayer, Daniela; Langs, Georg; Jakab, András; Schöpf, Veronika

    2014-01-01

    The functional connectivity architecture of the adult human brain enables complex cognitive processes, and exhibits a remarkably complex structure shared across individuals. We are only beginning to understand its heterogeneous structure, ranging from a strongly hierarchical organization in sensorimotor areas to widely distributed networks in areas such as the parieto-frontal cortex. Our study relied on the functional magnetic resonance imaging (fMRI) data of 32 fetuses with no detectable mor...

  10. DNA methylation in the human cerebral cortex is dynamically regulated throughout the life span and involves differentiated neurons.

    Directory of Open Access Journals (Sweden)

    Kimberly D Siegmund

    Full Text Available The role of DNA cytosine methylation, an epigenetic regulator of chromatin structure and function, during normal and pathological brain development and aging remains unclear. Here, we examined by MethyLight PCR the DNA methylation status at 50 loci, encompassing primarily 5' CpG islands of genes related to CNS growth and development, in temporal neocortex of 125 subjects ranging in age from 17 weeks of gestation to 104 years old. Two psychiatric disease cohorts--defined by chronic neurodegeneration (Alzheimer's or lack thereof (schizophrenia--were included. A robust and progressive rise in DNA methylation levels across the lifespan was observed for 8/50 loci (GABRA2, GAD1, HOXA1, NEUROD1, NEUROD2, PGR, STK11, SYK typically in conjunction with declining levels of the corresponding mRNAs. Another 16 loci were defined by a sharp rise in DNA methylation levels within the first few months or years after birth. Disease-associated changes were limited to 2/50 loci in the Alzheimer's cohort, which appeared to reflect an acceleration of the age-related change in normal brain. Additionally, methylation studies on sorted nuclei provided evidence for bidirectional methylation events in cortical neurons during the transition from childhood to advanced age, as reflected by significant increases at 3, and a decrease at 1 of 10 loci. Furthermore, the DNMT3a de novo DNA methyl-transferase was expressed across all ages, including a subset of neurons residing in layers III and V of the mature cortex. Therefore, DNA methylation is dynamically regulated in the human cerebral cortex throughout the lifespan, involves differentiated neurons, and affects a substantial portion of genes predominantly by an age-related increase.

  11. Pharmacological approach to the mechanisms of transcranial DC-stimulation-induced after-effects of human motor cortex excitability.

    Science.gov (United States)

    Liebetanz, David; Nitsche, Michael A; Tergau, Frithjof; Paulus, Walter

    2002-10-01

    Weak transcranial direct current stimulation (tDCS) induces persisting excitability changes in the human motor cortex. These plastic excitability changes are selectively controlled by the polarity, duration and current strength of stimulation. To reveal the underlying mechanisms of direct current (DC)-induced neuroplasticity, we combined tDCS of the motor cortex with the application of Na(+)-channel-blocking carbamazepine (CBZ) and the N-methyl-D-aspartate (NMDA)-receptor antagonist dextromethorphan (DMO). Monitored by transcranial magnetic stimulation (TMS), motor cortical excitability changes of up to 40% were achieved in the drug-free condition. Increase of cortical excitability could be selected by anodal stimulation, and decrease by cathodal stimulation. Both types of excitability change lasted several minutes after cessation of current stimulation. DMO suppressed the post-stimulation effects of both anodal and cathodal DC stimulation, strongly suggesting the involvement of NMDA receptors in both types of DC-induced neuroplasticity. In contrast, CBZ selectively eliminated anodal effects. Since CBZ stabilizes the membrane potential voltage-dependently, the results reveal that after-effects of anodal tDCS require a depolarization of membrane potentials. Similar to the induction of established types of short- or long-term neuroplasticity, a combination of glutamatergic and membrane mechanisms is necessary to induce the after-effects of tDCS. On the basis of these results, we suggest that polarity-driven alterations of resting membrane potentials represent the crucial mechanisms of the DC-induced after-effects, leading to both an alteration of spontaneous discharge rates and to a change in NMDA-receptor activation.

  12. Relationship between BOLD amplitude and pattern classification of orientation-selective activity in the human visual cortex

    Science.gov (United States)

    Tong, Frank; Harrison, Stephenie A.; Dewey, John A.; Kamitani, Yukiyasu

    2012-01-01

    Orientation-selective responses can be decoded from fMRI activity patterns in the human visual cortex, using multivariate pattern analysis (MVPA). To what extent do these feature-selective activity patterns depend on the strength and quality of the sensory input, and might the reliability of these activity patterns be predicted by the gross amplitude of the stimulus-driven BOLD response? Observers viewed oriented gratings that varied in luminance contrast (4, 20 or 100%) or spatial frequency (0.25, 1.0 or 4.0 cpd). As predicted, activity patterns in early visual areas led to better discrimination of orientations presented at high than low contrast, with greater effects of contrast found in area V1 than in V3. A second experiment revealed generally better decoding of orientations at low or moderate as compared to high spatial frequencies. Interestingly however, V1 exhibited a relative advantage at discriminating high spatial frequency orientations, consistent with the finer scale of representation in the primary visual cortex. In both experiments, the reliability of these orientation-selective activity patterns was well predicted by the average BOLD amplitude in each region of interest, as indicated by correlation analyses, as well as decoding applied to a simple model of voxel responses to simulated orientation columns. Moreover, individual differences in decoding accuracy could be predicted by the signal-to-noise ratio of an individual's BOLD response. Our results indicate that decoding accuracy can be well predicted by incorporating the amplitude of the BOLD response into simple simulation models of cortical selectivity; such models could prove useful in future applications of fMRI pattern classification. PMID:22917989

  13. Is the ipsilateral cortex surrounding the lesion or the non-injured contralateral cortex important for motor recovery in rats with photochemically induced cortical lesions?

    Science.gov (United States)

    Takata, Kotaro; Yamauchi, Hideki; Tatsuno, Hisashi; Hashimoto, Keiji; Abo, Masahiro

    2006-01-01

    To determine whether the ipsilateral cortex surrounding the lesion or the non-injured contralateral cortex is important for motor recovery after brain damage in the photochemically initiated thrombosis (PIT) model. We induced PIT in the sensorimotor cortex in rats and examined the recovery of motor function using the beam-walking test. In 24 rats, the right sensorimotor cortex was lesioned after 2 days of training for the beam-walking test (group 1). After 10 days, PIT was induced in the left sensorimotor cortex. Eight additional rats (group 2) received 2 days training in beam walking, then underwent the beam-walking test to evaluate function. After 10 days of testing, the left sensorimotor cortex was lesioned and recovery was monitored by the beam-walking test for 8 days. In group 1 animals, left hindlimb function caused by a right sensorimotor cortex lesion recovered within 10 days after the operation. Right hindlimb function caused by the left-side lesion recovered within 6 days. In group 2, right hindlimb function caused by induction of the left-side lesion after a total of 12 days of beam-walking training and testing recovered within 6 days as with the double PIT model. The training effect may be relevant to reorganization and neuromodulation. Motor recovery patterns did not indicate whether motor recovery was dependent on the ipsilateral cortex surrounding the lesion or the cortex of the contralateral side. The results emphasize the need for selection of appropriate programs tailored to the area of cortical damage in order to enhance motor functional recovery in this model. Copyright 2006 S. Karger AG, Basel.

  14. Shutting down sensorimotor interference unblocks the networks for stimulus processing: an SMR neurofeedback training study.

    Science.gov (United States)

    Kober, Silvia Erika; Witte, Matthias; Stangl, Matthias; Väljamäe, Aleksander; Neuper, Christa; Wood, Guilherme

    2015-01-01

    In the present study, we investigated how the electrical activity in the sensorimotor cortex contributes to improved cognitive processing capabilities and how SMR (sensorimotor rhythm, 12-15Hz) neurofeedback training modulates it. Previous evidence indicates that higher levels of SMR activity reduce sensorimotor interference and thereby promote cognitive processing. Participants were randomly assigned to two groups, one experimental (N=10) group receiving SMR neurofeedback training, in which they learned to voluntarily increase SMR, and one control group (N=10) receiving sham feedback. Multiple cognitive functions and electrophysiological correlates of cognitive processing were assessed before and after 10 neurofeedback training sessions. The experimental group but not the control group showed linear increases in SMR power over training runs, which was associated with behavioural improvements in memory and attentional performance. Additionally, increasing SMR led to a more salient stimulus processing as indicated by increased N1 and P3 event-related potential amplitudes after the training as compared to the pre-test. Finally, functional brain connectivity between motor areas and visual processing areas was reduced after SMR training indicating reduced sensorimotor interference. These results indicate that SMR neurofeedback improves stimulus processing capabilities and consequently leads to improvements in cognitive performance. The present findings contribute to a better understanding of the mechanisms underlying SMR neurofeedback training and cognitive processing and implicate that SMR neurofeedback might be an effective cognitive training tool. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  15. Assessment of sensorimotor cortical representation asymmetries and motor skills in violin players.

    Science.gov (United States)

    Schwenkreis, Peter; El Tom, Susan; Ragert, Patrick; Pleger, Burkhard; Tegenthoff, Martin; Dinse, Hubert R

    2007-12-01

    As a model for use-dependent plasticity, the brains of professional musicians have been extensively studied to examine structural and functional adaptation to unique requirements of skilled performance. Here we provide a combination of data on motor performance and hand representation in the primary motor and somatosensory cortex of professional violin players, with the aim of assessing possible behavioural consequences of sensorimotor cortical asymmetries. We studied 15 healthy right-handed professional violin players and 35 healthy nonmusician controls. Motor and somatosensory cortex asymmetry was assessed by recording the motor output map after transcranial magnetic stimulation from a small hand muscle, and by dipole source localization of somatosensory evoked potentials after electrical stimulation of the median and ulnar nerves. Motor performance was examined using a series of standardized motor tasks covering different aspects of hand function. Violin players showed a significant right-larger-than-left asymmetry of the motor and somatosensory cortex, whereas nonmusician controls showed no significant interhemispheric difference. The amount of asymmetry in the motor and somatosensory cortices of musicians was significantly correlated. At the behavioural level, motor performance did not significantly differ between musicians and nonmusicians. The results support a use-dependent enlargement of the left hand representation in the sensorimotor cortex of violin players. However, these cortical asymmetries were not paralleled by accompanying altered asymmetries at a behavioural level, suggesting that the reorganisation might be task-specific and does not lead to improved motor abilities in general.

  16. [Neuroanatomy of Frontal Association Cortex].

    Science.gov (United States)

    Takada, Masahiko

    2016-11-01

    The frontal association cortex is composed of the prefrontal cortex and the motor-related areas except the primary motor cortex (i.e., the so-called higher motor areas), and is well-developed in primates, including humans. The prefrontal cortex receives and integrates large bits of diverse information from the parietal, temporal, and occipital association cortical areas (termed the posterior association cortex), and paralimbic association cortical areas. This information is then transmitted to the primary motor cortex via multiple motor-related areas. Given these facts, it is likely that the prefrontal cortex exerts executive functions for behavioral control. The functional input pathways from the posterior and paralimbic association cortical areas to the prefrontal cortex are classified primarily into six groups. Cognitive signals derived from the prefrontal cortex are conveyed to the rostral motor-related areas to transform them into motor signals, which finally enter the primary motor cortex via the caudal motor-related areas. Furthermore, it has been shown that, similar to the primary motor cortex, areas of the frontal association cortex form individual networks (known as "loop circuits") with the basal ganglia and cerebellum via the thalamus, and hence are extensively involved in the expression and control of behavioral actions.

  17. Functional neuroanatomy of human cortex cerebri in relation to wanting sex and having it.

    Science.gov (United States)

    Georgiadis, Janniko R

    2015-04-01

    Neuroanatomical textbooks typically restrict the central nervous system control of sexual responsiveness to the hypothalamus, brainstem and spinal cord. However, for all its primitive functions human sex is surprisingly complex and versatile. This review aims to extend the neuroanatomy of sexual responsiveness by providing a comprehensive overview of the empirical evidence for cerebral cortical involvement. To this end I will structure relevant human brain research data to fit the sexual pleasure cycle template-wanting sex, having sex, inhibiting sex-arguing that going through these sexual response phases requires adequate shifting between functional cortical networks. The relevance of this notion for understanding certain sexual dysfunctions is discussed. © 2015 Wiley Periodicals, Inc.

  18. Quantitative analysis of basal dendritic tree of layer III pyramidal neurons in different areas of adult human frontal cortex.

    Science.gov (United States)

    Zeba, Martina; Jovanov-Milosević, Natasa; Petanjek, Zdravko

    2008-01-01

    Large long projecting (cortico-cortical) layer IIIc pyramidal neurons were recently disclosed to be in the basis of cognitive processing in primates. Therefore, we quantitatively examined the basal dendritic morphology of these neurons by using rapid Golgi and Golgi Cox impregnation methods among three distinct Brodmann areas (BA) of an adult human frontal cortex: the primary motor BA4 and the associative magnopyramidal BA9 from left hemisphere and the Broca's speech BA45 from both hemispheres. There was no statistically significant difference in basal dendritic length or complexity, as dendritic spine number or their density between analyzed BA's. In addition, we analyzed each of these BA's immunocytochemically for distribution of SMI-32, a marker of largest long distance projecting neurons. Within layer IIIc, the highest density of SMI-32 immunopositive pyramidal neurons was observed in associative BA9, while in primary BA4 they were sparse. Taken together, these data suggest that an increase in the complexity of cortico-cortical network within human frontal areas of different functional order may be principally based on the increase in density of large, SMI-32 immunopositive layer IIIc neurons, rather than by further increase in complexity of their dendritic tree and synaptic network.

  19. Two eyes, one vision: binocular motion perception in human visual cortex

    NARCIS (Netherlands)

    Barendregt, M.

    2016-01-01

    An important aspect of human vision is the fact that it is binocular, i.e. that we have two eyes. As a result, the brain nearly always receives two slightly different images of the same visual scene. Yet, we only perceive a single image and thus our brain has to actively combine the binocular visual

  20. Functional Neuroanatomy of Human Cortex Cerebri in Relation to Wanting Sex and Having It

    NARCIS (Netherlands)

    Georgiadis, Janniko R.

    Neuroanatomical textbooks typically restrict the central nervous system control of sexual responsiveness to the hypothalamus, brainstem and spinal cord. However, for all its primitive functions human sex is surprisingly complex and versatile. This review aims to extend the neuroanatomy of sexual

  1. Neuromagnetic Representation of Musical Register Information in HumaN Auditory Cortex

    NARCIS (Netherlands)

    Andermann, M.; Van Dinther, C.H.B.A.; Patterson, R.D.; Rupp, A.

    2011-01-01

    Pulse-resonance sounds like vowels or instrumental tones contain acoustic information about the physical size of the sound source (pulse rate) and body resonators (resonance scale). Previous research has revealed correlates of these variables in humans using functional neuroimaging. Here, we report

  2. In-vivo magnetic resonance imaging (MRI) of laminae in the human cortex

    NARCIS (Netherlands)

    Trampel, Robert; Bazin, Pierre-Louis; Pine, Kerrin; Weiskopf, Nikolaus

    2018-01-01

    The human neocortex is organized radially into six layers which differ in their myelination and the density and arrangement of neuronal cells. This cortical cyto- and myeloarchitecture plays a central role in the anatomical and functional neuroanatomy but is primarily accessible through invasive

  3. Macular pigment carotenoids in the retina and occipital cortex are related in humans

    Science.gov (United States)

    Objectives: Lutein and zeaxanthin are dietary carotenoids that preferentially accumulate in the macular region of the retina. Together with mesozeaxanthin, a conversion product of lutein in the macula, they form the macular pigment. Lutein is also the predominant carotenoid in human brain tissue and...

  4. Attraction of position preference by spatial attention throughout human visual cortex

    NARCIS (Netherlands)

    Klein, Barrie P.; Harvey, Ben M.; Dumoulin, Serge O.

    2014-01-01

    Voluntary spatial attention concentrates neural resources at the attended location. Here, we examined the effects of spatial attention on spatial position selectivity in humans. We measured population receptive fields (pRFs) using high-field functional MRI (fMRI) (7T) while subjects performed an

  5. Developing Personalized Sensorimotor Adaptability Countermeasures for Spaceflight

    Science.gov (United States)

    Mulavara, A. P.; Seidler, R. D.; Peters, B.; Cohen, H. S.; Wood, S.; Bloomberg, J. J.

    2016-01-01

    Astronauts experience sensorimotor disturbances during their initial exposure to microgravity and during the re-adaptation phase following a return to an Earth-gravitational environment. Interestingly, astronauts who return from spaceflight show substantial differences in their abilities to readapt to a gravitational environment. The ability to predict the manner and degree to which individual astronauts would be affected would improve the effectiveness of countermeasure training programs designed to enhance sensorimotor adaptability. In this paper we will be presenting results from our ground-based study that show how behavioral, brain imaging and genomic data may be used to predict individual differences in sensorimotor adaptability to novel sensorimotor environments. This approach will allow us to better design and implement sensorimotor adaptability training countermeasures against decrements in post-mission adaptive capability that are customized for each crewmember's sensory biases, adaptive capacity, brain structure, functional capacities, and genetic predispositions. The ability to customize adaptability training will allow more efficient use of crew time during training and will optimize training prescriptions for astronauts to ensure expected outcomes.

  6. Differential Recruitment of Parietal Cortex during Spatial and Non-spatial Reach Planning

    Directory of Open Access Journals (Sweden)

    Pierre-Michel Bernier

    2017-05-01

    Full Text Available The planning of goal-directed arm reaching movements is associated with activity in the dorsal parieto-frontal cortex, within which multiple regions subserve the integration of arm- and target-related sensory signals to encode a motor goal. Surprisingly, many of these regions show sustained activity during reach preparation even when target location is not specified, i.e., when a motor goal cannot be unambiguously formed. The functional role of these non-spatial preparatory signals remains unresolved. Here this process was investigated in humans by comparing reach preparatory activity in the presence or absence of information regarding upcoming target location. In order to isolate the processes specific to reaching and to control for visuospatial attentional factors, the reaching task was contrasted to a finger movement task. Functional MRI and electroencephalography (EEG were used to characterize the spatio-temporal pattern of reach-related activity in the parieto-frontal cortex. Reach planning with advance knowledge of target location induced robust blood oxygenated level dependent and EEG responses across parietal and premotor regions contralateral to the reaching arm. In contrast, reach preparation without knowledge of target location was associated with a significant BOLD response bilaterally in the parietal cortex. Furthermore, EEG alpha- and beta-band activity was restricted to parietal scalp sites, the magnitude of the latter being correlated with reach reaction times. These results suggest an intermediate stage of sensorimotor transformations in bilateral parietal cortex when target location is not specified.

  7. Parietal operculum and motor cortex activities predict motor recovery in moderate to severe stroke

    Directory of Open Access Journals (Sweden)

    Firdaus Fabrice Hannanu

    2017-01-01

    In subacute stroke, fMRI brain activity related to passive movement measured in a sensorimotor network defined by activity during voluntary movement predicted motor recovery better than baseline motor-FMS alone. Furthermore, fMRI sensorimotor network activity measures considered alone allowed excellent clinical recovery prediction and may provide reliable biomarkers for assessing new therapies in clinical trial contexts. Our findings suggest that neural reorganization related to motor recovery from moderate to severe stroke results from balanced changes in ipsilesional MI (BA4a and a set of phylogenetically more archaic sensorimotor regions in the ventral sensorimotor trend, in which OP1 and OP4 processes may complement the ipsilesional dorsal motor cortex in achieving compensatory sensorimotor recovery.

  8. Internally generated preactivation of single neurons in human medial frontal cortex predicts volition

    OpenAIRE

    Fried, Itzhak; Mukamel, Roy; Kreiman, Gabriel

    2011-01-01

    Understanding how self-initiated behavior is encoded by neuronal circuits in the human brain remains elusive. We recorded the activity of 1019 neurons while twelve subjects performed self-initiated finger movement. We report progressive neuronal recruitment over ∼1500 ms before subjects report making the decision to move. We observed progressive increase or decrease in neuronal firing rate, particularly in the supplementary motor area (SMA), as the reported time of decision was approached. A ...

  9. Single to Two Cluster State Transition of Primary Motor Cortex 4-posterior (MI-4p Activities in Humans

    Directory of Open Access Journals (Sweden)

    Kazunori Nakada

    2015-11-01

    Full Text Available The human primary motor cortex has dual representation of the digits, namely, area 4 anterior (MI-4a and area 4 posterior (MI-4p. We have previously demonstrated that activation of these two functional subunits can be identified independently by functional magnetic resonance imaging (fMRI using independent component-cross correlation-sequential epoch (ICS analysis. Subsequent studies in patients with hemiparesis due to subcortical lesions and monoparesis due to peripheral nerve injury demonstrated that MI-4p represents the initiation area of activation, whereas MI-4a is the secondarily activated motor cortex requiring a “long-loop” feedback input from secondary motor systems, likely the cerebellum. A dynamic model of hand motion based on the limit cycle oscillator predicts that the specific pattern of entrainment of neural firing may occur by applying appropriate periodic stimuli. Under normal conditions, such entrainment introduces a single phase-cluster. Under pathological conditions where entrainment stimuli have insufficient strength, the phase cluster splits into two clusters. Observable physiological phenomena of this shift from single cluster to two clusters are: doubling of firing rate of output neurons; or decay in group firing density of the system due to dampening of odd harmonics components. While the former is not testable in humans, the latter can be tested by appropriately designed fMRI experiments, the quantitative index of which is believed to reflect group behavior of neurons functionally localized, e.g., firing density in the dynamic theory. Accordingly, we performed dynamic analysis of MI-4p activation in normal volunteers and paretic patients. The results clearly indicated that MI-4p exhibits a transition from a single to a two phase-cluster state which coincided with loss of MI-4a activation. The study demonstrated that motor dysfunction (hemiparesis in patients with a subcortical infarct is not simply due to afferent

  10. Decoding conjunctions of direction-of-motion and binocular disparity from human visual cortex.

    Science.gov (United States)

    Seymour, Kiley J; Clifford, Colin W G

    2012-05-01

    Motion and binocular disparity are two features in our environment that share a common correspondence problem. Decades of psychophysical research dedicated to understanding stereopsis suggest that these features interact early in human visual processing to disambiguate depth. Single-unit recordings in the monkey also provide evidence for the joint encoding of motion and disparity across much of the dorsal visual stream. Here, we used functional MRI and multivariate pattern analysis to examine where in the human brain conjunctions of motion and disparity are encoded. Subjects sequentially viewed two stimuli that could be distinguished only by their conjunctions of motion and disparity. Specifically, each stimulus contained the same feature information (leftward and rightward motion and crossed and uncrossed disparity) but differed exclusively in the way these features were paired. Our results revealed that a linear classifier could accurately decode which stimulus a subject was viewing based on voxel activation patterns throughout the dorsal visual areas and as early as V2. This decoding success was conditional on some voxels being individually sensitive to the unique conjunctions comprising each stimulus, thus a classifier could not rely on independent information about motion and binocular disparity to distinguish these conjunctions. This study expands on evidence that disparity and motion interact at many levels of human visual processing, particularly within the dorsal stream. It also lends support to the idea that stereopsis is subserved by early mechanisms also tuned to direction of motion.

  11. Coordinated gene expression of neuroinflammatory and cell signaling markers in dorsolateral prefrontal cortex during human brain development and aging.

    Science.gov (United States)

    Primiani, Christopher T; Ryan, Veronica H; Rao, Jagadeesh S; Cam, Margaret C; Ahn, Kwangmi; Modi, Hiren R; Rapoport, Stanley I

    2014-01-01

    Age changes in expression of inflammatory, synaptic, and neurotrophic genes are not well characterized during human brain development and senescence. Knowing these changes may elucidate structural, metabolic, and functional brain processes over the lifespan, as well vulnerability to neurodevelopmental or neurodegenerative diseases. Expression levels of inflammatory, synaptic, and neurotrophic genes in the human brain are coordinated over the lifespan and underlie changes in phenotypic networks or cascades. We used a large-scale microarray dataset from human prefrontal cortex, BrainCloud, to quantify age changes over the lifespan, divided into Development (0 to 21 years, 87 brains) and Aging (22 to 78 years, 144 brains) intervals, in transcription levels of 39 genes. Gene expression levels followed different trajectories over the lifespan. Many changes were intercorrelated within three similar groups or clusters of genes during both Development and Aging, despite different roles of the gene products in the two intervals. During Development, changes were related to reported neuronal loss, dendritic growth and pruning, and microglial events; TLR4, IL1R1, NFKB1, MOBP, PLA2G4A, and PTGS2 expression increased in the first years of life, while expression of synaptic genes GAP43 and DBN1 decreased, before reaching plateaus. During Aging, expression was upregulated for potentially pro-inflammatory genes such as NFKB1, TRAF6, TLR4, IL1R1, TSPO, and GFAP, but downregulated for neurotrophic and synaptic integrity genes such as BDNF, NGF, PDGFA, SYN, and DBN1. Coordinated changes in gene transcription cascades underlie changes in synaptic, neurotrophic, and inflammatory phenotypic networks during brain Development and Aging. Early postnatal expression changes relate to neuronal, glial, and myelin growth and synaptic pruning events, while late Aging is associated with pro-inflammatory and synaptic loss changes. Thus, comparable transcriptional regulatory networks that operate

  12. Coordinated gene expression of neuroinflammatory and cell signaling markers in dorsolateral prefrontal cortex during human brain development and aging.

    Directory of Open Access Journals (Sweden)

    Christopher T Primiani

    Full Text Available Age changes in expression of inflammatory, synaptic, and neurotrophic genes are not well characterized during human brain development and senescence. Knowing these changes may elucidate structural, metabolic, and functional brain processes over the lifespan, as well vulnerability to neurodevelopmental or neurodegenerative diseases.Expression levels of inflammatory, synaptic, and neurotrophic genes in the human brain are coordinated over the lifespan and underlie changes in phenotypic networks or cascades.We used a large-scale microarray dataset from human prefrontal cortex, BrainCloud, to quantify age changes over the lifespan, divided into Development (0 to 21 years, 87 brains and Aging (22 to 78 years, 144 brains intervals, in transcription levels of 39 genes.Gene expression levels followed different trajectories over the lifespan. Many changes were intercorrelated within three similar groups or clusters of genes during both Development and Aging, despite different roles of the gene products in the two intervals. During Development, changes were related to reported neuronal loss, dendritic growth and pruning, and microglial events; TLR4, IL1R1, NFKB1, MOBP, PLA2G4A, and PTGS2 expression increased in the first years of life, while expression of synaptic genes GAP43 and DBN1 decreased, before reaching plateaus. During Aging, expression was upregulated for potentially pro-inflammatory genes such as NFKB1, TRAF6, TLR4, IL1R1, TSPO, and GFAP, but downregulated for neurotrophic and synaptic integrity genes such as BDNF, NGF, PDGFA, SYN, and DBN1.Coordinated changes in gene transcription cascades underlie changes in synaptic, neurotrophic, and inflammatory phenotypic networks during brain Development and Aging. Early postnatal expression changes relate to neuronal, glial, and myelin growth and synaptic pruning events, while late Aging is associated with pro-inflammatory and synaptic loss changes. Thus, comparable transcriptional regulatory networks

  13. Coordinated Gene Expression of Neuroinflammatory and Cell Signaling Markers in Dorsolateral Prefrontal Cortex during Human Brain Development and Aging

    Science.gov (United States)

    Primiani, Christopher T.; Ryan, Veronica H.; Rao, Jagadeesh S.; Cam, Margaret C.; Ahn, Kwangmi; Modi, Hiren R.; Rapoport, Stanley I.

    2014-01-01

    Background Age changes in expression of inflammatory, synaptic, and neurotrophic genes are not well characterized during human brain development and senescence. Knowing these changes may elucidate structural, metabolic, and functional brain processes over the lifespan, as well vulnerability to neurodevelopmental or neurodegenerative diseases. Hypothesis Expression levels of inflammatory, synaptic, and neurotrophic genes in the human brain are coordinated over the lifespan and underlie changes in phenotypic networks or cascades. Methods We used a large-scale microarray dataset from human prefrontal cortex, BrainCloud, to quantify age changes over the lifespan, divided into Development (0 to 21 years, 87 brains) and Aging (22 to 78 years, 144 brains) intervals, in transcription levels of 39 genes. Results Gene expression levels followed different trajectories over the lifespan. Many changes were intercorrelated within three similar groups or clusters of genes during both Development and Aging, despite different roles of the gene products in the two intervals. During Development, changes were related to reported neuronal loss, dendritic growth and pruning, and microglial events; TLR4, IL1R1, NFKB1, MOBP, PLA2G4A, and PTGS2 expression increased in the first years of life, while expression of synaptic genes GAP43 and DBN1 decreased, before reaching plateaus. During Aging, expression was upregulated for potentially pro-inflammatory genes such as NFKB1, TRAF6, TLR4, IL1R1, TSPO, and GFAP, but downregulated for neurotrophic and synaptic integrity genes such as BDNF, NGF, PDGFA, SYN, and DBN1. Conclusions Coordinated changes in gene transcription cascades underlie changes in synaptic, neurotrophic, and inflammatory phenotypic networks during brain Development and Aging. Early postnatal expression changes relate to neuronal, glial, and myelin growth and synaptic pruning events, while late Aging is associated with pro-inflammatory and synaptic loss changes. Thus, comparable

  14. Syntactic Structures as Descriptions of Sensorimotor Processes

    Directory of Open Access Journals (Sweden)

    Alistair Knott

    2014-02-01

    Full Text Available In this paper I propose a hypothesis linking elements of a model of theoretical syntax with neural mechanisms in the domain of sensorimotor processing. The syntactic framework I adopt to express this linking hypothesis is Chomsky’s Minimalism: I propose that the language-independent ’Logical Form’ (LF of a sentence reporting a concrete episode in the world can be interpreted as a detailed description of the sensorimotor processes involved in apprehending that episode. The hypothesis is motivated by a detailed study of one particular episode, in which an agent grasps a target object. There are striking similarities between the LF structure of transitive sentences describing this episode and the structure of the sensorimotor processes through which it is apprehended by an observer. The neural interpretation of Minimalist LF structure allows it to incorporate insights from empiricist accounts of syntax, relating to sentence processing and to the learning of syntactic constructions.

  15. Prior Knowledge about Objects Determines Neural Color Representation in Human Visual Cortex.

    Science.gov (United States)

    Vandenbroucke, A R E; Fahrenfort, J J; Meuwese, J D I; Scholte, H S; Lamme, V A F

    2016-04-01

    To create subjective experience, our brain must translate physical stimulus input by incorporating prior knowledge and expectations. For example, we perceive color and not wavelength information, and this in part depends on our past experience with colored objects ( Hansen et al. 2006; Mitterer and de Ruiter 2008). Here, we investigated the influence of object knowledge on the neural substrates underlying subjective color vision. In a functional magnetic resonance imaging experiment, human subjects viewed a color that lay midway between red and green (ambiguous with respect to its distance from red and green) presented on either typical red (e.g., tomato), typical green (e.g., clover), or semantically meaningless (nonsense) objects. Using decoding techniques, we could predict whether subjects viewed the ambiguous color on typical red or typical green objects based on the neural response of veridical red and green. This shift of neural response for the ambiguous color did not occur for nonsense objects. The modulation of neural responses was observed in visual areas (V3, V4, VO1, lateral occipital complex) involved in color and object processing, as well as frontal areas. This demonstrates that object memory influences wavelength information relatively early in the human visual system to produce subjective color vision. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  16. Repeated Structural Imaging Reveals Nonlinear Progression of Experience-Dependent Volume Changes in Human Motor Cortex.

    Science.gov (United States)

    Wenger, Elisabeth; Kühn, Simone; Verrel, Julius; Mårtensson, Johan; Bodammer, Nils Christian; Lindenberger, Ulman; Lövdén, Martin

    2017-05-01

    Evidence for experience-dependent structural brain change in adult humans is accumulating. However, its time course is not well understood, as intervention studies typically consist of only 2 imaging sessions (before vs. after training). We acquired up to 18 structural magnetic resonance images over a 7-week period while 15 right-handed participants practiced left-hand writing and drawing. After 4 weeks, we observed increases in gray matter of both left and right primary motor cortices relative to a control group; 3 weeks later, these differences were no longer reliable. Time-series analyses revealed that gray matter in the primary motor cortices expanded during the first 4 weeks and then partially renormalized, in particular in the right hemisphere, despite continued practice and increasing task proficiency. Similar patterns of expansion followed by partial renormalization are also found in synaptogenesis, cortical map plasticity, and maturation, and may qualify as a general principle of structural plasticity. Research on human brain plasticity needs to encompass more than 2 measurement occasions to capture expansion and potential renormalization processes over time. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  17. Resilient protein co-expression network in male orbitofrontal cortex layer 2/3 during human aging.

    Science.gov (United States)

    Pabba, Mohan; Scifo, Enzo; Kapadia, Fenika; Nikolova, Yuliya S; Ma, Tianzhou; Mechawar, Naguib; Tseng, George C; Sibille, Etienne

    2017-10-01

    The orbitofrontal cortex (OFC) is vulnerable to normal and pathologic aging. Currently, layer resolution large-scale proteomic studies describing "normal" age-related alterations at OFC are not available. Here, we performed a large-scale exploratory high-throughput mass spectrometry-based protein analysis on OFC layer 2/3 from 15 "young" (15-43 years) and 18 "old" (62-88 years) human male subjects. We detected 4193 proteins and identified 127 differentially expressed (DE) proteins (p-value ≤0.05; effect size >20%), including 65 up- and 62 downregulated proteins (e.g., GFAP, CALB1). Using a previously described categorization of biological aging based on somatic tissues, that is, peripheral "hallmarks of aging," and considering overlap in protein function, we show the highest representation of altered cell-cell communication (54%), deregulated nutrient sensing (39%), and loss of proteostasis (35%) in the set of OFC layer 2/3 DE proteins. DE proteins also showed a significant association with several neurologic disorders; for example, Alzheimer's disease and schizophrenia. Notably, despite age-related changes in individual protein levels, protein co-expression modules were remarkably conserved across age groups, suggesting robust functional homeostasis. Collectively, these results provide biological insight into aging and associated homeostatic mechanisms that maintain normal brain function with advancing age. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Spatiotopic coding of BOLD signal in human visual cortex depends on spatial attention.

    Directory of Open Access Journals (Sweden)

    Sofia Crespi

    Full Text Available The neural substrate of the phenomenological experience of a stable visual world remains obscure. One possible mechanism would be to construct spatiotopic neural maps where the response is selective to the position of the stimulus in external space, rather than to retinal eccentricities, but evidence for these maps has been inconsistent. Here we show, with fMRI, that when human subjects perform concomitantly a demanding attentive task on stimuli displayed at the fovea, BOLD responses evoked by moving stimuli irrelevant to the task were mostly tuned in retinotopic coordinates. However, under more unconstrained conditions, where subjects could attend easily to the motion stimuli, BOLD responses were tuned not in retinal but in external coordinates (spatiotopic selectivity in many visual areas, including MT, MST, LO and V6, agreeing with our previous fMRI study. These results indicate that spatial attention may play an important role in mediating spatiotopic selectivity.

  19. Proscription supports robust perceptual integration by suppression in human visual cortex.

    Science.gov (United States)

    Rideaux, Reuben; Welchman, Andrew E

    2018-04-17

    Perception relies on integrating information within and between the senses, but how does the brain decide which pieces of information should be integrated and which kept separate? Here we demonstrate how proscription can be used to solve this problem: certain neurons respond best to unrealistic combinations of features to provide 'what not' information that drives suppression of unlikely perceptual interpretations. First, we present a model that captures both improved perception when signals are consistent (and thus should be integrated) and robust estimation when signals are conflicting. Second, we test for signatures of proscription in the human brain. We show that concentrations of inhibitory neurotransmitter GABA in a brain region intricately involved in integrating cues (V3B/KO) correlate with robust integration. Finally, we show that perturbing excitation/inhibition impairs integration. These results highlight the role of proscription in robust perception and demonstrate the functional purpose of 'what not' sensors in supporting sensory estimation.

  20. Internally generated preactivation of single neurons in human medial frontal cortex predicts volition

    Science.gov (United States)

    Fried, Itzhak; Mukamel, Roy; Kreiman, Gabriel

    2011-01-01

    Understanding how self-initiated behavior is encoded by neuronal circuits in the human brain remains elusive. We recorded the activity of 1019 neurons while twelve subjects performed self-initiated finger movement. We report progressive neuronal recruitment over ~1500 ms before subjects report making the decision to move. We observed progressive increase or decrease in neuronal firing rate, particularly in the supplementary motor area (SMA), as the reported time of decision was approached. A population of 256 SMA neurons is sufficient to predict in single trials the impending decision to move with accuracy greater than 80% already 700 ms prior to subjects’ awareness. Furthermore, we predict, with a precision of a few hundred ms, the actual time point of this voluntary decision to move. We implement a computational model whereby volition emerges once a change in internally generated firing rate of neuronal assemblies crosses a threshold. PMID:21315264

  1. Partially non-linear stimulation intensity-dependent effects of direct current stimulation on motor cortex excitability in humans.

    Science.gov (United States)

    Batsikadze, G; Moliadze, V; Paulus, W; Kuo, M-F; Nitsche, M A

    2013-04-01

    Transcranial direct current stimulation (tDCS) of the human motor cortex at an intensity of 1 mA with an electrode size of 35 cm(2) has been shown to induce shifts of cortical excitability during and after stimulation. These shifts are polarity-specific with cathodal tDCS resulting in a decrease and anodal stimulation in an increase of cortical excitability. In clinical and cognitive studies, stronger stimulation intensities are used frequently, but their physiological effects on cortical excitability have not yet been explored. Therefore, here we aimed to explore the effects of 2 mA tDCS on cortical excitability. We applied 2 mA anodal or cathodal tDCS for 20 min on the left primary motor cortex of 14 healthy subjects. Cathodal tDCS at 1 mA and sham tDCS for 20 min was administered as control session in nine and eight healthy subjects, respectively. Motor cortical excitability was monitored by transcranial magnetic stimulation (TMS)-elicited motor-evoked potentials (MEPs) from the right first dorsal interosseous muscle. Global corticospinal excitability was explored via single TMS pulse-elicited MEP amplitudes, and motor thresholds. Intracortical effects of stimulation were obtained by cortical silent period (CSP), short latency intracortical inhibition (SICI) and facilitation (ICF), and I wave facilitation. The above-mentioned protocols were recorded both before and immediately after tDCS in randomized order. Additionally, single-pulse MEPs, motor thresholds, SICI and ICF were recorded every 30 min up to 2 h after stimulation end, evening of the same day, next morning, next noon and next evening. Anodal as well as cathodal tDCS at 2 mA resulted in a significant increase of MEP amplitudes, whereas 1 mA cathodal tDCS decreased corticospinal excitability. A significant shift of SICI and ICF towards excitability enhancement after both 2 mA cathodal and anodal tDCS was observed. At 1 mA, cathodal tDCS reduced single-pulse TMS-elicited MEP amplitudes and shifted SICI

  2. Region-specific maturation of cerebral cortex in human fetal brain: diffusion tensor imaging and histology

    International Nuclear Information System (INIS)

    Trivedi, Richa; Gupta, Rakesh K.; Saksena, Sona; Husain, Nuzhat; Srivastava, Savita; Rathore, Ram K.S.; Sarma, Manoj K.; Malik, Gyanendra K.; Das, Vinita; Pradhan, Mandakini; Pandey, Chandra M.; Narayana, Ponnada A.

    2009-01-01

    In this study, diffusion tensor imaging (DTI) and glial fibrillary acidic protein (GFAP) immunohistochemical analysis in different cortical regions in fetal brains at different gestational age (GA) were performed. DTI was performed on 50 freshly aborted fetal brains with GA ranging from 12 to 42 weeks to compare age-related fractional anisotropy (FA) changes in different cerebral cortical regions that include frontal, parietal, occipital, and temporal lobes at the level of thalami. GFAP immunostaining was performed and the percentage of GFAP-positive areas was quantified. The cortical FA values in the frontal lobe peaked at around 26 weeks of GA, occipital and temporal lobes at around 20 weeks, and parietal lobe at around 23 weeks. A significant, but modest, positive correlation (r=0.31, p=0.02) was observed between cortical FA values and percentage area of GFAP expression in cortical region around the time period during which the migrational events are at its peak, i.e., GA ≤ 28 weeks for frontal cortical region and GA≤22 weeks for rest of the lobes. The DTI-derived FA quantification with its GFAP immunohistologic correlation in cortical regions of the various lobes of the cerebral hemispheres supports region-specific migrational and maturational events in human fetal brain. (orig.)

  3. Region-specific maturation of cerebral cortex in human fetal brain: diffusion tensor imaging and histology

    Energy Technology Data Exchange (ETDEWEB)

    Trivedi, Richa; Gupta, Rakesh K.; Saksena, Sona [Sanjay Gandhi Post Graduate Institute of Medical Sciences, Department of Radiodiagnosis, Lucknow, UP (India); Husain, Nuzhat; Srivastava, Savita [CSM Medical University, Department of Pathology, Lucknow (India); Rathore, Ram K.S.; Sarma, Manoj K. [Indian Institute of Technology, Department of Mathematics and Statistics, Kanpur (India); Malik, Gyanendra K. [CSM Medical University, Department of Pediatrics, Lucknow (India); Das, Vinita [CSM Medical University, Department of Obstetrics and Gynecology, Lucknow (India); Pradhan, Mandakini [Sanjay Gandhi Postgraduate Institute of Medical Sciences, Department of Medical Genetics, Lucknow (India); Pandey, Chandra M. [Sanjay Gandhi Postgraduate Institute of Medical Sciences, Department of Biostatistics, Lucknow (India); Narayana, Ponnada A. [University of Texas Medical School at Houston, Department of Diagnostic and Interventional Imaging, Houston, TX (United States)

    2009-09-15

    In this study, diffusion tensor imaging (DTI) and glial fibrillary acidic protein (GFAP) immunohistochemical analysis in different cortical regions in fetal brains at different gestational age (GA) were performed. DTI was performed on 50 freshly aborted fetal brains with GA ranging from 12 to 42 weeks to compare age-related fractional anisotropy (FA) changes in different cerebral cortical regions that include frontal, parietal, occipital, and temporal lobes at the level of thalami. GFAP immunostaining was performed and the percentage of GFAP-positive areas was quantified. The cortical FA values in the frontal lobe peaked at around 26 weeks of GA, occipital and temporal lobes at around 20 weeks, and parietal lobe at around 23 weeks. A significant, but modest, positive correlation (r=0.31, p=0.02) was observed between cortical FA values and percentage area of GFAP expression in cortical region around the time period during which the migrational events are at its peak, i.e., GA {<=} 28 weeks for frontal cortical region and GA{<=}22 weeks for rest of the lobes. The DTI-derived FA quantification with its GFAP immunohistologic correlation in cortical regions of the various lobes of the cerebral hemispheres supports region-specific migrational and maturational events in human fetal brain. (orig.)

  4. Explaining neural signals in human visual cortex with an associative learning model.

    Science.gov (United States)

    Jiang, Jiefeng; Schmajuk, Nestor; Egner, Tobias

    2012-08-01

    "Predictive coding" models posit a key role for associative learning in visual cognition, viewing perceptual inference as a process of matching (learned) top-down predictions (or expectations) against bottom-up sensory evidence. At the neural level, these models propose that each region along the visual processing hierarchy entails one set of processing units encoding predictions of bottom-up input, and another set computing mismatches (prediction error or surprise) between predictions and evidence. This contrasts with traditional views of visual neurons operating purely as bottom-up feature detectors. In support of the predictive coding hypothesis, a recent human neuroimaging study (Egner, Monti, & Summerfield, 2010) showed that neural population responses to expected and unexpected face and house stimuli in the "fusiform face area" (FFA) could be well-described as a summation of hypothetical face-expectation and -surprise signals, but not by feature detector responses. Here, we used computer simulations to test whether these imaging data could be formally explained within the broader framework of a mathematical neural network model of associative learning (Schmajuk, Gray, & Lam, 1996). Results show that FFA responses could be fit very closely by model variables coding for conditional predictions (and their violations) of stimuli that unconditionally activate the FFA. These data document that neural population signals in the ventral visual stream that deviate from classic feature detection responses can formally be explained by associative prediction and surprise signals.

  5. Task-dependent enhancement of facial expression and identity representations in human cortex.

    Science.gov (United States)

    Dobs, Katharina; Schultz, Johannes; Bülthoff, Isabelle; Gardner, Justin L

    2018-05-15

    What cortical mechanisms allow humans to easily discern the expression or identity of a face? Subjects detected changes in expression or identity of a stream of dynamic faces while we measured BOLD responses from topographically and functionally defined areas throughout the visual hierarchy. Responses in dorsal areas increased during the expression task, whereas responses in ventral areas increased during the identity task, consistent with previous studies. Similar to ventral areas, early visual areas showed increased activity during the identity task. If visual responses are weighted by perceptual mechanisms according to their magnitude, these increased responses would lead to improved attentional selection of the task-appropriate facial aspect. Alternatively, increased responses could be a signature of a sensitivity enhancement mechanism that improves representations of the attended facial aspect. Consistent with the latter sensitivity enhancement mechanism, attending to expression led to enhanced decoding of exemplars of expression both in early visual and dorsal areas relative to attending identity. Similarly, decoding identity exemplars when attending to identity was improved in dorsal and ventral areas. We conclude that attending to expression or identity of dynamic faces is associated with increased selectivity in representations consistent with sensitivity enhancement. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

  6. Attraction of position preference by spatial attention throughout human visual cortex.

    Science.gov (United States)

    Klein, Barrie P; Harvey, Ben M; Dumoulin, Serge O

    2014-10-01

    Voluntary spatial attention concentrates neural resources at the attended location. Here, we examined the effects of spatial attention on spatial position selectivity in humans. We measured population receptive fields (pRFs) using high-field functional MRI (fMRI) (7T) while subjects performed an attention-demanding task at different locations. We show that spatial attention attracts pRF preferred positions across the entire visual field, not just at the attended location. This global change in pRF preferred positions systematically increases up the visual hierarchy. We model these pRF preferred position changes as an interaction between two components: an attention field and a pRF without the influence of attention. This computational model suggests that increasing effects of attention up the hierarchy result primarily from differences in pRF size and that the attention field is similar across the visual hierarchy. A similar attention field suggests that spatial attention transforms different neural response selectivities throughout the visual hierarchy in a similar manner. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Using virtual reality to augment perception, enhance sensorimotor adaptation, and change our minds.

    Science.gov (United States)

    Wright, W Geoffrey

    2014-01-01

    Technological advances that involve human sensorimotor processes can have both intended and unintended effects on the central nervous system (CNS). This mini review focuses on the use of virtual environments (VE) to augment brain functions by enhancing perception, eliciting automatic motor behavior, and inducing sensorimotor adaptation. VE technology is becoming increasingly prevalent in medical rehabilitation, training simulators, gaming, and entertainment. Although these VE applications have often been shown to optimize outcomes, whether it be to speed recovery, reduce training time, or enhance immersion and enjoyment, there are inherent drawbacks to environments that can potentially change sensorimotor calibration. Across numerous VE studies over the years, we have investigated the effects of combining visual and physical motion on perception, motor control, and adaptation. Recent results from our research involving exposure to dynamic passive motion within a visually-depicted VE reveal that short-term exposure to augmented sensorimotor discordance can result in systematic aftereffects that last beyond the exposure period. Whether these adaptations are advantageous or not, remains to be seen. Benefits as well as risks of using VE-driven sensorimotor stimulation to enhance brain processes will be discussed.

  8. Using virtual reality to augment perception, enhance sensorimotor adaptation, and change our minds

    Directory of Open Access Journals (Sweden)

    W. Geoffrey Wright

    2014-04-01

    Full Text Available Technological advances that involve human sensorimotor processes can have both intended and unintended effects on the central nervous system (CNS. This mini-review focuses on the use of virtual environments (VE to augment brain functions by enhancing perception, eliciting automatic motor behavior, and inducing sensorimotor adaptation. VE technology is becoming increasingly prevalent in medical rehabilitation, training simulators, gaming, and entertainment. Although these VE applications have often been shown to optimize outcomes, whether it be to speed recovery, reduce training time, or enhance immersion and enjoyment, there are inherent drawbacks to environments that can potentially change sensorimotor calibration. Across numerous VE studies over the years, we have investigated the effects of combining visual and physical motion on perception, motor control, and adaptation. Recent results from our research involving exposure to dynamic passive motion within a visually-depicted VE reveal that short-term exposure to augmented sensorimotor discordance can result in systematic aftereffects that last beyond the exposure period. Whether these adaptations are advantageous or not, remains to be seen. Benefits as well as risks of using VE-driven sensorimotor stimulation to enhance brain processes will be discussed.

  9. Retinotopy and attention to the face and house images in the human visual cortex.

    Science.gov (United States)

    Wang, Bin; Yan, Tianyi; Ohno, Seiichiro; Kanazawa, Susumu; Wu, Jinglong

    2016-06-01

    Attentional modulation of the neural activities in human visual areas has been well demonstrated. However, the retinotopic activities that are driven by face and house images and attention to face and house images remain unknown. In the present study, we used images of faces and houses to estimate the retinotopic activities that were driven by both the images and attention to the images, driven by attention to the images, and driven by the images. Generally, our results show that both face and house images produced similar retinotopic activities in visual areas, which were only observed in the attention + stimulus and the attention conditions, but not in the stimulus condition. The fusiform face area (FFA) responded to faces that were presented on the horizontal meridian, whereas parahippocampal place area (PPA) rarely responded to house at any visual field. We further analyzed the amplitudes of the neural responses to the target wedge. In V1, V2, V3, V3A, lateral occipital area 1 (LO-1), and hV4, the neural responses to the attended target wedge were significantly greater than those to the unattended target wedge. However, in LO-2, ventral occipital areas 1 and 2 (VO-1 and VO-2) and FFA and PPA, the differences were not significant. We proposed that these areas likely have large fields of attentional modulation for face and house images and exhibit responses to both the target wedge and the background stimuli. In addition, we proposed that the absence of retinotopic activity in the stimulus condition might imply no perceived difference between the target wedge and the background stimuli.

  10. Object Representations in Human Visual Cortex Formed Through Temporal Integration of Dynamic Partial Shape Views.

    Science.gov (United States)

    Orlov, Tanya; Zohary, Ehud

    2018-01-17

    We typically recognize visual objects using the spatial layout of their parts, which are present simultaneously on the retina. Therefore, shape extraction is based on integration of the relevant retinal information over space. The lateral occipital complex (LOC) can represent shape faithfully in such conditions. However, integration over time is sometimes required to determine object shape. To study shape extraction through temporal integration of successive partial shape views, we presented human participants (both men and women) with artificial shapes that moved behind a narrow vertical or horizontal slit. Only a tiny fraction of the shape was visible at any instant at the same retinal location. However, observers perceived a coherent whole shape instead of a jumbled pattern. Using fMRI and multivoxel pattern analysis, we searched for brain regions that encode temporally integrated shape identity. We further required that the representation of shape should be invariant to changes in the slit orientation. We show that slit-invariant shape information is most accurate in the LOC. Importantly, the slit-invariant shape representations matched the conventional whole-shape representations assessed during full-image runs. Moreover, when the same slit-dependent shape slivers were shuffled, thereby preventing their spatiotemporal integration, slit-invariant shape information was reduced dramatically. The slit-invariant representation of the various shapes also mirrored the structure of shape perceptual space as assessed by perceptual similarity judgment tests. Therefore, the LOC is likely to mediate temporal integration of slit-dependent shape views, generating a slit-invariant whole-shape percept. These findings provide strong evidence for a global encoding of shape in the LOC regardless of integration processes required to generate the shape percept. SIGNIFICANCE STATEMENT Visual objects are recognized through spatial integration of features available simultaneously on

  11. Enhanced peripheral visual processing in congenitally deaf humans is supported by multiple brain regions, including primary auditory cortex

    Directory of Open Access Journals (Sweden)

    Gregory D. Scott

    2014-03-01

    Full Text Available Brain reorganization associated with altered sensory experience clarifies the critical role of neuroplasticity in development. An example is enhanced peripheral visual processing associated with congenital deafness, but the neural systems supporting this have not been fully characterized. A gap in our understanding of deafness-enhanced peripheral vision is the contribution of primary auditory cortex. Previous studies of auditory cortex that use anatomical normalization across participants were limited by inter-subject variability of Heschl’s gyrus. In addition to reorganized auditory cortex (cross-modal plasticity, a second gap in our understanding is the contribution of altered modality-specific cortices (visual intramodal plasticity in this case, as well as supramodal and multisensory cortices, especially when target detection is required across contrasts. Here we address these gaps by comparing fMRI signal change for peripheral versus perifoveal visual stimulation (11-15° vs. 2°-7° in congenitally deaf and hearing participants in a blocked experimental design with two analytical approaches: a Heschl’s gyrus region of interest analysis and a whole brain analysis. Our results using individually-defined primary auditory cortex (Heschl’s gyrus indicate that fMRI signal change for more peripheral stimuli was greater than perifoveal in deaf but not in hearing participants. Whole-brain analyses revealed differences between deaf and hearing participants for peripheral versus perifoveal visual processing in extrastriate visual cortex including primary auditory cortex, MT+/V5, superior-temporal auditory and multisensory and/or supramodal regions, such as posterior parietal cortex, frontal eye fields, anterior cingulate, and supplementary eye fields. Overall, these data demonstrate the contribution of neuroplasticity in multiple systems including primary auditory cortex, supramodal and multisensory regions, to altered visual processing in

  12. Enhanced peripheral visual processing in congenitally deaf humans is supported by multiple brain regions, including primary auditory cortex

    OpenAIRE

    Scott, Gregory D.; Karns, Christina M.; Dow, Mark W.; Stevens, Courtney; Neville, Helen J.

    2014-01-01

    Brain reorganization associated with altered sensory experience clarifies the critical role of neuroplasticity in development. An example is enhanced peripheral visual processing associated with congenital deafness, but the neural systems supporting this have not been fully characterized. A gap in our understanding of deafness-enhanced peripheral vision is the contribution of primary auditory cortex. Previous studies of auditory cortex that use anato