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Sample records for premotor cortical areas

  1. Dopamine replacement modulates oscillatory coupling between premotor and motor cortical areas in Parkinson's disease

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    Herz, Damian Marc; Florin, Esther; Christensen, Mark Schram;

    2014-01-01

    Efficient neural communication between premotor and motor cortical areas is critical for manual motor control. Here, we used high-density electroencephalography to study cortical connectivity in patients with Parkinson's disease (PD) and age-matched healthy controls while they performed repetitive...

  2. Alpha, beta and gamma electrocorticographic rhythms in somatosensory, motor, premotor and prefrontal cortical areas differ in movement execution and observation in humans.

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    Babiloni, Claudio; Del Percio, Claudio; Vecchio, Fabrizio; Sebastiano, Fabio; Di Gennaro, Giancarlo; Quarato, Pier P; Morace, Roberta; Pavone, Luigi; Soricelli, Andrea; Noce, Giuseppe; Esposito, Vincenzo; Rossini, Paolo Maria; Gallese, Vittorio; Mirabella, Giovanni

    2016-01-01

    In the present study, we tested the hypothesis that both movement execution and observation induce parallel modulations of alpha, beta, and gamma electrocorticographic (ECoG) rhythms in primary somatosensory (Brodmann area 1-2, BA1-2), primary motor (BA4), ventral premotor (BA6), and prefrontal (BA44 and BA45, part of putative human mirror neuron system underlying the understanding of actions of other people) areas. ECoG activity was recorded in drug-resistant epileptic patients during the execution of actions to reach and grasp common objects according to their affordances, as well as during the observation of the same actions performed by an experimenter. Both action execution and observation induced a desynchronization of alpha and beta rhythms in BA1-2, BA4, BA6, BA44 and BA45, which was generally higher in amplitude during the former than the latter condition. Action execution also induced a major synchronization of gamma rhythms in BA4 and BA6, again more during the execution of an action than during its observation. Human primary sensorimotor, premotor, and prefrontal areas do generate alpha, beta, and gamma rhythms and differently modulate them during action execution and observation. Gamma rhythms of motor areas are especially involved in action execution. Oscillatory activity of neural populations in sensorimotor, premotor and prefrontal (part of human mirror neuron system) areas represents and distinguishes own actions from those of other people. This methodological approach might be used for a neurophysiological diagnostic imaging of social cognition in epileptic patients. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  3. Somatosensory-motor adaptation of orofacial actions in posterior parietal and ventral premotor cortices.

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    Krystyna Grabski

    Full Text Available Recent studies have provided evidence for sensory-motor adaptive changes and action goal coding of visually guided manual action in premotor and posterior parietal cortices. To extend these results to orofacial actions, devoid of auditory and visual feedback, we used a repetition suppression paradigm while measuring neural activity with functional magnetic resonance imaging during repeated intransitive and silent lip, jaw and tongue movements. In the motor domain, this paradigm refers to decreased activity in specific neural populations due to repeated motor acts and has been proposed to reflect sensory-motor adaptation. Orofacial movements activated a set of largely overlapping, common brain areas forming a core neural network classically involved in orofacial motor control. Crucially, suppressed neural responses during repeated orofacial actions were specifically observed in the left ventral premotor cortex, the intraparietal sulcus, the inferior parietal lobule and the superior parietal lobule. Since no visual and auditory feedback were provided during orofacial actions, these results suggest somatosensory-motor adaptive control of intransitive and silent orofacial actions in these premotor and parietal regions.

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

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    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.

  5. Decoding a wide range of hand configurations from macaque motor, premotor, and parietal cortices.

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    Schaffelhofer, Stefan; Agudelo-Toro, Andres; Scherberger, Hansjörg

    2015-01-21

    Despite recent advances in decoding cortical activity for motor control, the development of hand prosthetics remains a major challenge. To reduce the complexity of such applications, higher cortical areas that also represent motor plans rather than just the individual movements might be advantageous. We investigated the decoding of many grip types using spiking activity from the anterior intraparietal (AIP), ventral premotor (F5), and primary motor (M1) cortices. Two rhesus monkeys were trained to grasp 50 objects in a delayed task while hand kinematics and spiking activity from six implanted electrode arrays (total of 192 electrodes) were recorded. Offline, we determined 20 grip types from the kinematic data and decoded these hand configurations and the grasped objects with a simple Bayesian classifier. When decoding from AIP, F5, and M1 combined, the mean accuracy was 50% (using planning activity) and 62% (during motor execution) for predicting the 50 objects (chance level, 2%) and substantially larger when predicting the 20 grip types (planning, 74%; execution, 86%; chance level, 5%). When decoding from individual arrays, objects and grip types could be predicted well during movement planning from AIP (medial array) and F5 (lateral array), whereas M1 predictions were poor. In contrast, predictions during movement execution were best from M1, whereas F5 performed only slightly worse. These results demonstrate for the first time that a large number of grip types can be decoded from higher cortical areas during movement preparation and execution, which could be relevant for future neuroprosthetic devices that decode motor plans.

  6. It's how you get there: Walking down a virtual alley activates premotor and parietal areas

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    Johanna eWagner

    2014-02-01

    Full Text Available Voluntary drive is crucial for motor learning, therefore we are interested in the role that motor planning plays in gait movements. In this study we examined the impact of an interactive Virtual Environment (VE feedback task on the EEG patterns during robot assisted walking. We compared walking in the VE modality to two control conditions: walking with a visual attention paradigm, in which visual stimuli were unrelated to the motor task; and walking with mirror feedback, in which participants observed their own movements. Eleven healthy participants were considered. Application of independent component analysis to the EEG revealed three independent component clusters in premotor and parietal areas showing increased activity during walking with the adaptive VE training paradigm compared to the control conditions. During the interactive VE walking task spectral power in frequency ranges 8-12Hz, 15-20Hz and 23-40Hz was significantly (p ≤ 0.05 decreased. This power decrease is interpreted as a correlate of an active cortical area. Furthermore activity in the premotor cortex revealed gait cycle related modulations significantly different (p ≤ 0.05 from baseline in the frequency range 23-40Hz during walking. These modulations were significantly (p ≤ 0.05 reduced depending on gait cycle phases in the interactive VE walking task compared to the control conditions.We demonstrate that premotor and parietal areas show increased activity during walking with the adaptive VE training paradigm, when compared to walking with mirror- and movement unrelated feedback. Previous research has related a premotor-parietal network to motor planning and motor intention. We argue that movement related interactive feedback enhances motor planning and motor intention. We hypothesize that this might improve gait recovery during rehabilitation.

  7. Coordinated activation of premotor and ventromedial prefrontal cortices during vicarious reward.

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    Shimada, Sotaro; Matsumoto, Madoka; Takahashi, Hidefumi; Yomogida, Yukihito; Matsumoto, Kenji

    2016-03-01

    The vicarious reward we receive from watching likable others obtaining a positive outcome is a pervasive phenomenon, yet its neural correlates are poorly understood. Here, we conducted a series of functional magnetic resonance imaging experiments to test the hypothesis that the brain areas responsible for action observation and reward processing work in a coordinated fashion during vicarious reward. In the first experiment (manipulation phase), the participant was instructed to cheer for a particular player in a two-player competitive game (Rock-Paper-Scissors). This manipulation made participants feel more unity with that player and resulted in unity-related activation in the premotor area during action observation. In the following main experiment, the participant witnessed the previously cheered-for or non-cheered-for player succeed in a new solitary game (a stopwatch game). The ventromedial prefrontal cortex (vmPFC) was activated when the cheered-for player succeeded in the game but not when the other player did. Interestingly, this vmPFC activation was functionally connected with premotor activation only during the cheered-for player's success. These results suggest that vicarious reward is processed in the vmPFC-premotor network, which is activated specifically by the success of the other person with whom the individual feels unity and closeness.

  8. Motor and premotor cortices in subcortical stroke: proton magnetic resonance spectroscopy measures and arm motor impairment.

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    Craciunas, Sorin C; Brooks, William M; Nudo, Randolph J; Popescu, Elena A; Choi, In-Young; Lee, Phil; Yeh, Hung-Wen; Savage, Cary R; Cirstea, Carmen M

    2013-06-01

    Although functional imaging and neurophysiological approaches reveal alterations in motor and premotor areas after stroke, insights into neurobiological events underlying these alterations are limited in human studies. We tested whether cerebral metabolites related to neuronal and glial compartments are altered in the hand representation in bilateral motor and premotor areas and correlated with distal and proximal arm motor impairment in hemiparetic persons. In 20 participants at >6 months postonset of a subcortical ischemic stroke and 16 age- and sex-matched healthy controls, the concentrations of N-acetylaspartate and myo-inositol were quantified by proton magnetic resonance spectroscopy. Regions of interest identified by functional magnetic resonance imaging included primary (M1), dorsal premotor (PMd), and supplementary (SMA) motor areas. Relationships between metabolite concentrations and distal (hand) and proximal (shoulder/elbow) motor impairment using Fugl-Meyer Upper Extremity (FMUE) subscores were explored. N-Acetylaspartate was lower in M1 (P = .04) and SMA (P = .004) and myo-inositol was higher in M1 (P = .003) and PMd (P = .03) in the injured (ipsilesional) hemisphere after stroke compared with the left hemisphere in controls. N-Acetylaspartate in ipsilesional M1 was positively correlated with hand FMUE subscores (P = .04). Significant positive correlations were also found between N-acetylaspartate in ipsilesional M1, PMd, and SMA and in contralesional M1 and shoulder/elbow FMUE subscores (P = .02, .01, .02, and .02, respectively). Our preliminary results demonstrated that proton magnetic resonance spectroscopy is a sensitive method to quantify relevant neuronal changes in spared motor cortex after stroke and consequently increase our knowledge of the factors leading from these changes to arm motor impairment.

  9. Single-cell coding of sensory, spatial and numerical magnitudes in primate prefrontal, premotor and cingulate motor cortices.

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    Eiselt, Anne-Kathrin; Nieder, Andreas

    2016-01-01

    The representation of magnitude information enables humans and animal species alike to successfully interact with the external environment. However, how various types of magnitudes are processed by single neurons to guide goal-directed behavior remains elusive. Here, we recorded single-cell activity from the dorsolateral prefrontal (PFC), dorsal premotor (PMd) and cingulate motor (CMA) cortices in monkeys discriminating discrete numerical (numerosity), continuous spatial (line length) and basic sensory (spatial frequency) stimuli. We found that almost exclusively PFC neurons represented the different magnitude types during sample presentation and working memory periods. The frequency of magnitude-selective cells in PMd and CMA did not exceed chance level. The proportion of PFC neurons selectively tuned to each of the three magnitude types were comparable. Magnitude coding was mainly dissociated at the single-neuron level, with individual neurons representing only one of the three tested magnitude types. Neuronal magnitude discriminability, coding strength and temporal evolution were comparable between magnitude types encoded by PFC neuron populations. Our data highlight the importance of PFC neurons in representing various magnitude categories. Such magnitude representations are based on largely distributed coding by single neurons that are anatomically intermingled within the same cortical area.

  10. Rule activity related to spatial and numerical magnitudes: comparison of prefrontal, premotor, and cingulate motor cortices.

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    Eiselt, Anne-Kathrin; Nieder, Andreas

    2014-05-01

    In everyday situations, quantitative rules, such as "greater than/less than," need to be applied to a multitude of magnitude comparisons, be they sensory, spatial, temporal, or numerical. We have previously shown that rules applied to different magnitudes are encoded in the lateral PFC. To investigate if and how other frontal lobe areas also contribute to the encoding of quantitative rules applied to multiple magnitudes, we trained monkeys to switch between "greater than/less than" rules applied to either line lengths (spatial magnitudes) or dot numerosities (discrete numerical magnitudes). We recorded single-cell activity from the dorsal premotor cortex (dPMC) and cingulate motor cortex (CMA) and compared it with PFC activity. We found the largest proportion of quantitative rule-selective cells in PFC (24% of randomly selected cells), whereas neurons in dPMC and CMA rarely encoded the rule (6% of the cells). In addition, rule selectivity of individual cells was highest in PFC neurons compared with dPMC and CMA neurons. Rule-selective neurons that simultaneously represented the "greater than/less than" rules applied to line lengths and numerosities ("rule generalists") were exclusively present in PFC. In dPMC and CMA, however, neurons primarily encoded rules applied to only one of the two magnitude types ("rule specialists"). Our data suggest a special involvement of PFC in representing quantitative rules at an abstract level, both in terms of the proportion of neurons engaged and the coding capacities.

  11. Neural correlate of subjective sensory experience gradually builds up across cortical areas

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    de Lafuente, Victor; Romo, Ranulfo

    2006-01-01

    When a sensory stimulus is presented, many cortical areas are activated, but how does the representation of a sensory stimulus evolve in time and across cortical areas during a perceptual judgment? We investigated this question by analyzing the responses from single neurons, recorded in several cortical areas of parietal and frontal lobes, while trained monkeys reported the presence or absence of a mechanical vibration of varying amplitude applied to the skin of one fingertip. Here we show that the strength of the covariations between neuronal activity and perceptual judgments progressively increases across cortical areas as the activity is transmitted from the primary somatosensory cortex to the premotor areas of the frontal lobe. This finding suggests that the neuronal correlates of subjective sensory experience gradually build up across somatosensory areas of the parietal lobe and premotor cortices of the frontal lobe. PMID:16924098

  12. STOP-EVENT-RELATED POTENTIALS FROM INTRACRANIAL ELECTRODES REVEAL A KEY ROLE OF PREMOTOR AND MOTOR CORTICES IN STOPPING ONGOING MOVEMENTS

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    Maurizio eMattia

    2012-06-01

    Full Text Available In humans, the ability to withhold manual motor responses seems to rely on a right-lateralized frontal–basal ganglia–thalamic network, including the pre-supplementary motor area and the inferior frontal gyrus. These areas should drive subthalamic nuclei to implement movement inhibition via the hyperdirect pathway. The output of this network is expected to influence those cortical areas underlying limb movement preparation and initiation, i.e. premotor (PMA and primary motor (M1 cortices. Electroencephalographic (EEG studies have shown an enhancement of the N200/P300 complex in the event-related potentials (ERPs when a planned reaching movement is successfully stopped after the presentation of an infrequent stop-signal. PMA and M1 have been suggested as possible neural sources of this ERP complex but, due to the limited spatial resolution of scalp EEG, it is not yet clear which cortical areas contribute to its generation. To elucidate the role of motor cortices, we recorded epicortical ERPs from the lateral surface of the fronto-temporal lobes of five pharmacoresistant epileptic patients performing a reaching version of the countermanding task while undergoing presurgical monitoring. We consistently found a stereotyped ERP complex on a single-trial level when a movement was successfully cancelled. These ERPs were selectively expressed in M1, PMA and Brodmann's area (BA 9 and their onsets preceded the end of the stop process, suggesting a causal involvement in this executive function. Such ERPs also occurred in unsuccessful-stop trials, that is, when subjects moved despite the occurrence of a stop-signal, mostly when they had long reaction times. These findings support the hypothesis that motor cortices are the final target of the inhibitory command elaborated by the frontal–basal ganglia–thalamic network.

  13. Connecting to create: expertise in musical improvisation is associated with increased functional connectivity between premotor and prefrontal areas.

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    Pinho, Ana Luísa; de Manzano, Örjan; Fransson, Peter; Eriksson, Helene; Ullén, Fredrik

    2014-04-30

    Musicians have been used extensively to study neural correlates of long-term practice, but no studies have investigated the specific effects of training musical creativity. Here, we used human functional MRI to measure brain activity during improvisation in a sample of 39 professional pianists with varying backgrounds in classical and jazz piano playing. We found total hours of improvisation experience to be negatively associated with activity in frontoparietal executive cortical areas. In contrast, improvisation training was positively associated with functional connectivity of the bilateral dorsolateral prefrontal cortices, dorsal premotor cortices, and presupplementary areas. The effects were significant when controlling for hours of classical piano practice and age. These results indicate that even neural mechanisms involved in creative behaviors, which require a flexible online generation of novel and meaningful output, can be automated by training. Second, improvisational musical training can influence functional brain properties at a network level. We show that the greater functional connectivity seen in experienced improvisers may reflect a more efficient exchange of information within associative networks of importance for musical creativity.

  14. Activation of Premotor Vocal Areas during Musical Discrimination

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    Brown, Steven; Martinez, Michael J.

    2007-01-01

    Two same/different discrimination tasks were performed by amateur-musician subjects in this functional magnetic resonance imaging study: Melody Discrimination and Harmony Discrimination. Both tasks led to activations not only in classic working memory areas--such as the cingulate gyrus and dorsolateral prefrontal cortex--but in a series of…

  15. Evidence for a functional subdivision of Premotor Ear-Eye Field (Area 8B.

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    Marco eLanzilotto

    2015-01-01

    Full Text Available The Supplementary Eye Field (SEF and the Frontal Eye Field (FEF have been described as participating in gaze shift control. Recent evidence suggests, however, that other areas of the dorsomedial prefrontal cortex also influence gaze shift. Herein, we have investigated electrically evoked ear- and eye movements from the Premotor Ear-Eye Field, or PEEF (area 8B of macaque monkeys. We stimulated PEEF during spontaneous condition (outside the task performance and during the execution of a visual fixation task (VFT. In the first case, we functionally identified two regions within the PEEF: a core and a belt. In the core region, stimulation elicited forward ear movements; regarding the evoked eye movements, in some penetrations, stimulation elicited contraversive fixed-vectors with a mean amplitude of 5.14°; while in other penetrations, we observed prevalently contralateral goal-directed eye movements having end-points that fell within 15° in respect to the primary eye position. On the contrary, in the belt region, stimulation elicited backward ear movements; regarding the eye movements, in some penetrations stimulation elicited prevalently contralateral goal-directed eye movements having end-points that fell within 15° in respect to the primary eye position, while in the lateral edge of the investigated region, stimulation elicited contralateral goal-directed eye movements having end-points that fell beyond 15° in respect to the primary eye position. Stimulation during VFT either did not elicit eye movements or evoked saccades of only a few degrees. Finally, even though no head rotation movements were observed during the stimulation period, we viewed a relationship between the duration of stimulation and the neck forces exerted by the monkey’s head. We propose an updated vision of the PEEF composed of two functional regions, core and belt, which may be involved in integrating auditory and visual information important to the programming of gaze

  16. [Cortical Areas for Controlling Voluntary Movements].

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    Nakayama, Yoshihisa; Hoshi, Eiji

    2017-04-01

    The primary motor cortex is located in Brodmann area 4 at the most posterior part of the frontal lobe. The primary motor cortex corresponds to an output stage of motor signals, sending motor commands to the brain stem and spinal cord. Brodmann area 6 is rostral to Brodmann area 4, where multiple higher-order motor areas are located. The premotor area, which is located in the lateral part, is involved in planning and executing action based on sensory signals. The premotor area contributes to the reaching for and grasping of an object to achieve a behavioral goal. The supplementary motor area, which occupies the mesial aspect, is involved in planning and executing actions based on internalized or memorized signals. The supplementary motor area plays a central role in bimanual movements, organizing multiple movements, and switching from a routine to a controlled behavior. Thus, Brodmann areas 4 and 6 are considered as central motor areas in the cerebral cortex, in which the idea of an action is transformed to an actual movement in a variety of contexts.

  17. Levodopa reinstates connectivity from prefrontal to premotor cortex during externally paced movement in Parkinson's disease

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    Herz, Damian M; Siebner, Hartwig R; Hulme, Oliver J

    2014-01-01

    ), lateral premotor cortex (lPM), supplementary motor area (SMA) and primary motor cortex (M1). Dynamic causal modelling was used to characterize task-related oscillatory coupling between prefrontal and premotor cortical areas. Healthy participants showed task-induced coupling from PFC to SMA, which...... was modulated within the γ-band. In the OFF state, PD patients did not express any frequency-specific coupling between prefrontal and premotor areas. Application of levodopa reinstated task-related coupling from PFC to SMA, which was expressed as high-β-γ coupling. Additionally, strong within-frequency γ...

  18. Cortical areas involved in Arabic number reading.

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    Roux, F-E; Lubrano, V; Lauwers-Cances, V; Giussani, C; Démonet, J-F

    2008-01-15

    Distinct functional pathways for processing words and numbers have been hypothesized from the observation of dissociated impairments of these categories in brain-damaged patients. We aimed to identify the cortical areas involved in Arabic number reading process in patients operated on for various brain lesions. Direct cortical electrostimulation was prospectively used in 60 brain mappings. We used object naming and two reading tasks: alphabetic script (sentences and number words) and Arabic number reading. Cortical areas involved in Arabic number reading were identified according to location, type of interference, and distinctness from areas associated with other language tasks. Arabic number reading was sustained by small cortical areas, often extremely well localized (area (Brodmann area 45), the anterior part of the dominant supramarginal gyrus (Brodmann area 40; p area (Brodmann area 37; p areas.

  19. Automatic segmentation of human cortical layer-complexes and architectural areas using diffusion MRI and its validation

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    Matteo Bastiani

    2016-11-01

    Full Text Available Recently, several magnetic resonance imaging contrast mechanisms have been shown to distinguish cortical substructure corresponding to selected cortical layers. Here, we investigate cortical layer and area differentiation by automatized unsupervised clustering of high resolution diffusion MRI data. Several groups of adjacent layers could be distinguished in human primary motor and premotor cortex. We then used the signature of diffusion MRI signals along cortical depth as a criterion to detect area boundaries and find borders at which the signature changes abruptly. We validate our clustering results by histological analysis of the same tissue. These results confirm earlier studies which show that diffusion MRI can probe layer-specific intracortical fiber organization and, moreover, suggests that it contains enough information to automatically classify architecturally distinct cortical areas. We discuss the strengths and weaknesses of the automatic clustering approach and its appeal for MR-based cortical histology.

  20. Activation and connectivity patterns of the presupplementary and dorsal premotor areas during free improvisation of melodies and rhythms.

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    de Manzano, Örjan; Ullén, Fredrik

    2012-10-15

    Free, i.e. non-externally cued generation of movement sequences is fundamental to human behavior. We have earlier hypothesized that the dorsal premotor cortex (PMD), which has been consistently implicated in cognitive aspects of planning and selection of spatial motor sequences may be particularly important for the free generation of spatial movement sequences, whereas the pre-supplementary motor area (pre-SMA), which shows increased activation during perception, learning and reproduction of temporal sequences, may contribute more to the generation of temporal structures. Here we test this hypothesis using fMRI and musical improvisation in professional pianists as a model behavior. We employed a 2 × 2 factorial design with the factors Melody (Specified/Improvised) and Rhythm (Specified/Improvised). The main effect analyses partly confirmed our hypothesis: there was a main effect of Melody in the PMD; the pre-SMA was present in the main effect of Rhythm, as predicted, as well as in the main effect of Melody. A psychophysiological interaction analysis of functional connectivity demonstrated that the correlation in activity between the pre-SMA and cerebellum was higher during rhythmic improvisation than during the other conditions. In summary, there were only subtle differences in activity level between the pre-SMA and PMD during improvisation, regardless of condition. Consequently, the free generation of rhythmic and melodic structures, appears to be largely integrated processes but the functional connectivity between premotor areas and other regions may change during free generation in response to sequence-specific spatiotemporal demands.

  1. Evolution of premotor cortical excitability after cathodal inhibition of the primary motor cortex: a sham-controlled serial navigated TMS study.

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    Sein Schmidt

    Full Text Available BACKGROUND: Premotor cortical regions (PMC play an important role in the orchestration of motor function, yet their role in compensatory mechanisms in a disturbed motor system is largely unclear. Previous studies are consistent in describing pronounced anatomical and functional connectivity between the PMC and the primary motor cortex (M1. Lesion studies consistently show compensatory adaptive changes in PMC neural activity following an M1 lesion. Non-invasive brain modification of PMC neural activity has shown compensatory neurophysiological aftereffects in M1. These studies have contributed to our understanding of how M1 responds to changes in PMC neural activity. Yet, the way in which the PMC responds to artificial inhibition of M1 neural activity is unclear. Here we investigate the neurophysiological consequences in the PMC and the behavioral consequences for motor performance of stimulation mediated M1 inhibition by cathodal transcranial direct current stimulation (tDCS. PURPOSE: The primary goal was to determine how electrophysiological measures of PMC excitability change in order to compensate for inhibited M1 neural excitability and attenuated motor performance. HYPOTHESIS: Cathodal inhibition of M1 excitability leads to a compensatory increase of ipsilateral PMC excitability. METHODS: We enrolled 16 healthy participants in this randomized, double-blind, sham-controlled, crossover design study. All participants underwent navigated transcranial magnetic stimulation (nTMS to identify PMC and M1 corticospinal projections as well as to evaluate electrophysiological measures of cortical, intracortical and interhemispheric excitability. Cortical M1 excitability was inhibited using cathodal tDCS. Finger-tapping speeds were used to examine motor function. RESULTS: Cathodal tDCS successfully reduced M1 excitability and motor performance speed. PMC excitability was increased for longer and was the only significant predictor of motor performance

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

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

    2012-01-01

    (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......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......). A subthreshold conditioning stimulus (CS) was given to PMd 2.0-5.2 ms after the TS at intensities of 50-, 70-, or 90% of TS. The CS to PMd facilitated the MEP evoked by TS over M1(HAND) at interstimulus intervals (ISI) of 2.4 or 2.8 ms. There was a second facilitatory peak at ISI of 4.4 ms. PMd-to-M1(HAND...

  3. Reduced parietal connectivity with a premotor writing area in writer's cramp.

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    Delnooz, Cathérine C S; Helmich, Rick C; Toni, Ivan; van de Warrenburg, Bart P C

    2012-09-15

    Writer's cramp is a task-specific form of dystonia with symptoms characterized by abnormal movements and postures of the hand and arm evident only during writing. Its pathophysiology has been related to faulty sensorimotor integration, abnormal sensory processing, and impaired motor planning. Its symptoms might appear when the computational load of writing pushes a tonically altered circuit outside its operational range. Using resting-state fMRI, we tested whether writer's cramp patients have altered intrinsic functional connectivity in the premotor-parietal circuit. Sixteen patients with right-sided writer's cramp and 19 control subjects were studied. We show that writer's cramp patients have reduced connectivity between the superior parietal lobule and a dorsal precentral region that controls writing movements. This difference between patients and controls occurred in the absence of writing and only in the hemisphere contralateral to the affected hand. This finding adds a novel element to the pathophysiological substrate for writer's cramp, namely, task-independent alterations within a writing-related circuit.

  4. Effects of trains of high-frequency stimulation of the premotor/supplementary motor area on conditioned corticomotor responses in hemicerebellectomized rats.

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    Oulad Ben Taib, Nordeyn; Manto, Mario

    2008-07-01

    We studied the effects of low- and high-frequency premotor electrical stimulations on conditioned corticomotor responses, intra-cortical facilitation (ICF) and spinal excitability in hemicerebellectomized rats (left side). Trains of stimulation were applied in prefrontal region rFr2 (the equivalent of the premotor/supplementary motor area in primates) at a rate of 1 Hz (low-frequency stimulation LFS) or 20 Hz (high-frequency stimulation HFS). Test stimuli on the motor cortex were preceded by a conditioning stimulus in contralateral sciatic nerve (two inter-stimulus intervals ISIs were studied: 5 ms or 45 ms). (A) At ISI-5, conditioning increased amplitudes of MEPs (motor evoked potentials) in the left motor cortex. This afferent facilitation was enhanced if preceded by trains of stimuli administered over the ipsilateral rFr2 area, and HFS had higher effects than LFS. The facilitation was lower for the right motor cortex, for both LFS and HFS. (B) At ISI-45, conditioned motor evoked responses were depressed as compared to unconditioned responses in the left motor cortex (afferent inhibition). Following LFS, the degree of inhibition was unchanged while it increased with HFS. At baseline, inhibition was enhanced in the right motor cortex. Interestingly, the afferent inhibition decreased significantly following HFS. (C) ICF was depressed in the right motor cortex, but increased similarly on both sides following LFS/HFS. These results (1) confirm the increased inhibition in the motor cortex contralaterally to the hemicerebellar ablation, (2) demonstrate for the first time that the cerebellum is necessary for tuning amplitudes of corticomotor responses following a peripheral nerve stimulation, (3) show that the application of LFS or HFS does not cancel the defect of excitability in the motor cortex for short ISIs, and (4) suggest that for longer ISIs, HFS could have interesting properties for the modulation of afferent inhibition in case of extensive cerebellar lesion

  5. Prefrontal and agranular cingulate projections to the dorsal premotor areas F2 and F7 in the macaque monkey.

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    Luppino, Giuseppe; Rozzi, Stefano; Calzavara, Roberta; Matelli, Massimo

    2003-02-01

    The superior sector of Brodmann area 6 (dorsal premotor cortex, PMd) of the macaque monkey consists of a rostral and a caudal architectonic area referred to as F7 and F2, respectively. The aim of this study was to define the origin of prefrontal and agranular cingulate afferents to F7 and F2, in the light of functional and hodological evidence showing that these areas do not appear to be functionally homogeneous. Different sectors of F7 and F2 were injected with neural tracers in seven monkeys and the retrograde labelling was qualitatively and quantitatively analysed. The dorsorostral part of F7 (supplementary eye field, F7-SEF) was found to be a target of strong afferents from the frontal eye field (FEF), from the dorsolateral prefrontal regions located dorsally (DLPFd) and ventrally (DLPFv) to the principal sulcus and from cingulate areas 24a, 24b and 24c. In contrast, the remaining part of F7 (F7-non SEF) is only a target of the strong afferents from DLPFd. Finally, the ventrorostral part of F2 (F2vr), but not the F2 sector located around the superior precentral dimple (F2d), receives a minor, but significant, input from DLPFd and a relatively strong input from the cingulate gyrus (areas 24a and 24b) and area 24d. Present data provide strong hodological support in favour of the idea that areas F7 and F2 are formed by two functionally distinct sectors.

  6. Localization of cortical areas activated by thinking

    DEFF Research Database (Denmark)

    Roland, P E; Friberg, L

    1985-01-01

    These experiments were undertaken to demonstrate that pure mental activity, thinking, increases the cerebral blood flow and that different types of thinking increase the regional cerebral blood flow (rCBF) in different cortical areas. As a first approach, thinking was defined as brain work...... study was taken with the subjects at rest. Then the rCBF was measured during three different simple algorithm tasks, each consisting of retrieval of a specific memory followed by a simple operation on the retrieved information. Once started, the information processing went on in the brain without any...... that they started at their front door and then walked alternatively to the left or the right each time they reached a corner. The rCBF increased only in homotypical cortical areas during thinking. The areas in the superior prefrontal cortex increased their rCBF equivalently during the three types of thinking...

  7. View-based encoding of actions in mirror neurons of area f5 in macaque premotor cortex.

    Science.gov (United States)

    Caggiano, Vittorio; Fogassi, Leonardo; Rizzolatti, Giacomo; Pomper, Joern K; Thier, Peter; Giese, Martin A; Casile, Antonino

    2011-01-25

    Converging experimental evidence indicates that mirror neurons in the monkey premotor area F5 encode the goals of observed motor acts [1-3]. However, it is unknown whether they also contribute to encoding the perspective from which the motor acts of others are seen. In order to address this issue, we recorded the visual responses of mirror neurons of monkey area F5 by using a novel experimental paradigm based on the presentation of movies showing grasping motor acts from different visual perspectives. We found that the majority of the tested mirror neurons (74%) exhibited view-dependent activity with responses tuned to specific points of view. A minority of the tested mirror neurons (26%) exhibited view-independent responses. We conclude that view-independent mirror neurons encode action goals irrespective of the details of the observed motor acts, whereas the view-dependent ones might either form an intermediate step in the formation of view independence or contribute to a modulation of view-dependent representations in higher-level visual areas, potentially linking the goals of observed motor acts with their pictorial aspects. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. TMS-Induced Modulation of Action Sentence Priming in the Ventral Premotor Cortex

    Science.gov (United States)

    Tremblay, Pascale; Sato, Marc; Small, Steven L.

    2012-01-01

    Despite accumulating evidence that cortical motor areas, particularly the lateral premotor cortex, are activated during language comprehension, the question of whether motor processes help mediate the semantic encoding of language remains controversial. To address this issue, we examined whether low frequency (1 Hz) repetitive transcranial…

  9. Supplementary motor area and other cortical areas in organization of voluntary movements in man

    DEFF Research Database (Denmark)

    Roland, P E; Larsen, B; Lassen, N A

    1980-01-01

    in the contralateral primary motor area. In addition, there were more modest rCBF increases in the contralateral sensory hand area, the convexity part of the premotor area, and bilaterally in the inferior frontal region. 4. Repetitive fast flexions of the same finger or a sustained isometric muscular contraction raise...

  10. Mirror Neurons in Monkey Premotor Area F5 Show Tuning for Critical Features of Visual Causality Perception.

    Science.gov (United States)

    Caggiano, Vittorio; Fleischer, Falk; Pomper, Joern K; Giese, Martin A; Thier, Peter

    2016-11-21

    Humans derive causality judgments reliably from highly abstract stimuli, such as moving discs that bump into each other [1]. This fascinating visual capability emerges gradually during human development [2], perhaps as consequence of sensorimotor experience [3]. Human functional imaging studies suggest an involvement of the "action observation network" in the processing of such stimuli [4, 5]. In addition, theoretical studies suggest a link between the computational mechanisms of action and causality perception [6, 7], consistent with the fact that both functions require an analysis of sequences of spatiotemporal relationships between interacting stimulus elements. Single-cell correlates of the perception of causality are completely unknown. In order to find such neural correlates, we investigated the responses of "mirror neurons" in macaque premotor area F5 [8, 9]. These neurons respond during the observation as well as during the execution of actions and show interesting invariances, e.g., with respect to the stimulus view [10], occlusions [11], or whether an action is really executed or suppressed [12]. We investigated the spatiotemporal properties of the visual responses of mirror neurons to naturalistic hand action stimuli and to abstract stimuli, which specified the same causal relationships. We found a high degree of generalization between these two stimulus classes. In addition, many features that strongly reduced the similarity of the response patterns coincided with the ones that also destroy the perception of causality in humans. This implies an overlap of neural structures involved in the processing of actions and the visual perception of causality at the single-cell level. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. SMI-32 parcellates the visual cortical areas of the marmoset.

    Science.gov (United States)

    Baldauf, Zsolt B

    The distribution pattern of SMI-32-immunoreactivity (SMI-32-ir) of neuronal elements was examined in the visual cortical areas of marmoset monkey. Layer IV of the primary visual cortex (V1) and layers III and V of the extrastriate areas showed the most abundant SMI-32-ir. The different areal and laminar distribution of SMI-32-ir allowed the distinction between various extrastriate areas and determined their exact anatomical boundaries in the New World monkey, Callithrix penicillata. It is shown here that the parcellating nature of SMI-32 described earlier in the visual cortical areas of other mammals - including Old World monkeys - is also present in the marmoset. Furthermore, a comparison became possible between the chemoanatomical organization of New World and Old World primates' visual cortical areas.

  12. Relating normalization to neuronal populations across cortical areas.

    Science.gov (United States)

    Ruff, Douglas A; Alberts, Joshua J; Cohen, Marlene R

    2016-09-01

    Normalization, which divisively scales neuronal responses to multiple stimuli, is thought to underlie many sensory, motor, and cognitive processes. In every study where it has been investigated, neurons measured in the same brain area under identical conditions exhibit a range of normalization, ranging from suppression by nonpreferred stimuli (strong normalization) to additive responses to combinations of stimuli (no normalization). Normalization has been hypothesized to arise from interactions between neuronal populations, either in the same or different brain areas, but current models of normalization are not mechanistic and focus on trial-averaged responses. To gain insight into the mechanisms underlying normalization, we examined interactions between neurons that exhibit different degrees of normalization. We recorded from multiple neurons in three cortical areas while rhesus monkeys viewed superimposed drifting gratings. We found that neurons showing strong normalization shared less trial-to-trial variability with other neurons in the same cortical area and more variability with neurons in other cortical areas than did units with weak normalization. Furthermore, the cortical organization of normalization was not random: neurons recorded on nearby electrodes tended to exhibit similar amounts of normalization. Together, our results suggest that normalization reflects a neuron's role in its local network and that modulatory factors like normalization share the topographic organization typical of sensory tuning properties.

  13. Dissociable mechanisms of cognitive control in prefrontal and premotor cortex.

    Science.gov (United States)

    Chambers, Christopher D; Bellgrove, Mark A; Gould, Ian C; English, Therese; Garavan, Hugh; McNaught, Elizabeth; Kamke, Marc; Mattingley, Jason B

    2007-12-01

    Intelligent behavior depends on the ability to suppress inappropriate actions and resolve interference between competing responses. Recent clinical and neuroimaging evidence has demonstrated the involvement of prefrontal, parietal, and premotor areas during behaviors that emphasize conflict and inhibition. It remains unclear, however, whether discrete subregions within this network are crucial for overseeing more specific inhibitory demands. Here we probed the functional specialization of human prefrontal cortex by combining repetitive transcranial magnetic stimulation (rTMS) with integrated behavioral measures of response inhibition (stop-signal task) and response competition (flanker task). Participants undertook a combined stop-signal/flanker task after rTMS of the inferior frontal gyrus (IFG) or dorsal premotor cortex (dPM) in each hemisphere. Stimulation of the right IFG impaired stop-signal inhibition under conditions of heightened response competition but did not influence the ability to suppress a competing response. In contrast, stimulation of the right dPM facilitated execution but had no effect on inhibition. Neither of these results was observed during rTMS of corresponding left-hemisphere regions. Overall, our findings are consistent with existing evidence that the right IFG is crucial for inhibitory control. The observed double dissociation of neurodisruptive effects between the right IFG and right dPM further implies that response inhibition and execution rely on distinct neural processes despite activating a common cortical network.

  14. Activity in a premotor cortical nucleus of zebra finches is locally organized and exhibits auditory selectivity in neurons but not in glia.

    Directory of Open Access Journals (Sweden)

    Michael H Graber

    Full Text Available Motor functions are often guided by sensory experience, most convincingly illustrated by complex learned behaviors. Key to sensory guidance in motor areas may be the structural and functional organization of sensory inputs and their evoked responses. We study sensory responses in large populations of neurons and neuron-assistive cells in the songbird motor area HVC, an auditory-vocal brain area involved in sensory learning and in adult song production. HVC spike responses to auditory stimulation display remarkable preference for the bird's own song (BOS compared to other stimuli. Using two-photon calcium imaging in anesthetized zebra finches we measure the spatio-temporal structure of baseline activity and of auditory evoked responses in identified populations of HVC cells. We find strong correlations between calcium signal fluctuations in nearby cells of a given type, both in identified neurons and in astroglia. In identified HVC neurons only, auditory stimulation decorrelates ongoing calcium signals, less for BOS than for other sound stimuli. Overall, calcium transients show strong preference for BOS in identified HVC neurons but not in astroglia, showing diversity in local functional organization among identified neuron and astroglia populations.

  15. The activity in the contralateral primary motor cortex, dorsal premotor and supplementary motor area is modulated by performance gains

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    Ronen eSosnik

    2014-04-01

    Full Text Available There is growing experimental evidence that the engagement of different brain areas in a given motor task may change with practice, although the specific brain activity patterns underlying different stages of learning, as defined by kinematic or dynamic performance indices, are not well understood. Here we studied the change in activation in motor areas during practice on sequences of handwriting-like trajectories, connecting four target points on a digitizing table 'as rapidly and as accurately as possible' while lying inside an fMRI scanner. Analysis of the subjects' pooled kinematic and imaging data, acquired at the beginning, middle and end of the training period, revealed no correlation between the amount of activation in the contralateral M1, PM (dorsal and ventral, SMA, preSMA and PPC and the amount of practice per-se. Single trial analysis has revealed that the correlation between the amount of activation in the contralateral M1 and trial mean velocity was partially modulated by performance gains related effects, such as increased hand motion smoothness. Furthermore, it was found that the amount of activation in the contralateral preSMA increased when subjects shifted from generating straight point-to-point trajectories to their spatiotemporal concatenation into a smooth, curved trajectory. Altogether, our results indicate that the amount of activation in the contralateral M1, PMd and preSMA during the learning of movement sequences is correlated with performance gains and that high level motion features (e.g., motion smoothness may modulate, or even mask correlations between activity changes and low-level motion attributes (e.g., trial mean velocity.

  16. Differential activation of the lateral premotor cortex during action observation

    Directory of Open Access Journals (Sweden)

    Stark Rudolf

    2010-07-01

    Full Text Available Abstract Background Action observation leads to neural activation of the human premotor cortex. This study examined how the level of motor expertise (expert vs. novice in ballroom dancing and the visual viewpoint (internal vs. external viewpoint influence this activation within different parts of this area of the brain. Results Sixteen dance experts and 16 novices observed ballroom dance videos from internal or external viewpoints while lying in a functional magnetic resonance imaging scanner. A conjunction analysis of all observation conditions showed that action observation activated distinct networks of premotor, parietal, and cerebellar structures. Experts revealed increased activation in the ventral premotor cortex compared to novices. An internal viewpoint led to higher activation of the dorsal premotor cortex. Conclusions The present results suggest that the ventral and dorsal premotor cortex adopt differential roles during action observation depending on the level of motor expertise and the viewpoint.

  17. Representational gain in cortical area underlies increase of memory strength.

    Science.gov (United States)

    Bieszczad, Kasia M; Weinberger, Norman M

    2010-02-23

    Neuronal plasticity that develops in the cortex during learning is assumed to represent memory content, but the functions of such plasticity are actually unknown. The shift in spectral tuning in primary auditory cortex (A1) to the frequency of a tone signal is a compelling candidate for a substrate of memory because it has all of the cardinal attributes of associative memory: associativity, specificity, rapid induction, consolidation, and long-term retention. Tuning shifts increase the representational area of the signal in A1, as an increasing function of performance level, suggesting that area encodes the magnitude of acquired stimulus significance. The present study addresses the question of the specific function of learning-induced associative representational plasticity. We tested the hypothesis that specific increases in A1 representational area for an auditory signal serve the mnemonic function of enhancing memory strength for that signal. Rats were trained to bar-press for reward contingent on the presence of a signal tone (5.0 kHz), and assessed for memory strength during extinction. The amount of representational area gain for the signal frequency band was significantly positively correlated with resistance to extinction to the signal frequency in two studies that spanned the range of task difficulty. These findings indicate that specific gain in cortical representational area underlies the strength of the behaviorally-relevant contents of memory. Thus, mnemonic functions of cortical plasticity are determinable.

  18. Complex motor task associated with non-linear BOLD responses in cerebro-cortical areas and cerebellum.

    Science.gov (United States)

    Alahmadi, Adnan A S; Samson, Rebecca S; Gasston, David; Pardini, Matteo; Friston, Karl J; D'Angelo, Egidio; Toosy, Ahmed T; Wheeler-Kingshott, Claudia A M

    2016-06-01

    Previous studies have used fMRI to address the relationship between grip force (GF) applied to an object and BOLD response. However, whilst the majority of these studies showed a linear relationship between GF and neural activity in the contralateral M1 and ipsilateral cerebellum, animal studies have suggested the presence of non-linear components in the GF-neural activity relationship. Here, we present a methodology for assessing non-linearities in the BOLD response to different GF levels, within primary motor as well as sensory and cognitive areas and the cerebellum. To be sensitive to complex forms, we designed a feasible grip task with five GF targets using an event-related visually guided paradigm and studied a cohort of 13 healthy volunteers. Polynomial functions of increasing order were fitted to the data. (1) activated motor areas irrespective of GF; (2) positive higher-order responses in and outside M1, involving premotor, sensory and visual areas and cerebellum; (3) negative correlations with GF, predominantly involving the visual domain. Overall, our results suggest that there are physiologically consistent behaviour patterns in cerebral and cerebellar cortices; for example, we observed the presence of a second-order effect in sensorimotor areas, consistent with an optimum metabolic response at intermediate GF levels, while higher-order behaviour was found in associative and cognitive areas. At higher GF levels, sensory-related cortical areas showed reduced activation, interpretable as a redistribution of the neural activity for more demanding tasks. These results have the potential of opening new avenues for investigating pathological mechanisms of neurological diseases.

  19. Compensatory premotor activity during affective face processing in subclinical carriers of a single mutant Parkin allele.

    Science.gov (United States)

    Anders, Silke; Sack, Benjamin; Pohl, Anna; Münte, Thomas; Pramstaller, Peter; Klein, Christine; Binkofski, Ferdinand

    2012-04-01

    Patients with Parkinson's disease suffer from significant motor impairments and accompanying cognitive and affective dysfunction due to progressive disturbances of basal ganglia-cortical gating loops. Parkinson's disease has a long presymptomatic stage, which indicates a substantial capacity of the human brain to compensate for dopaminergic nerve degeneration before clinical manifestation of the disease. Neuroimaging studies provide evidence that increased motor-related cortical activity can compensate for progressive dopaminergic nerve degeneration in carriers of a single mutant Parkin or PINK1 gene, who show a mild but significant reduction of dopamine metabolism in the basal ganglia in the complete absence of clinical motor signs. However, it is currently unknown whether similar compensatory mechanisms are effective in non-motor basal ganglia-cortical gating loops. Here, we ask whether asymptomatic Parkin mutation carriers show altered patterns of brain activity during processing of facial gestures, and whether this might compensate for latent facial emotion recognition deficits. Current theories in social neuroscience assume that execution and perception of facial gestures are linked by a special class of visuomotor neurons ('mirror neurons') in the ventrolateral premotor cortex/pars opercularis of the inferior frontal gyrus (Brodmann area 44/6). We hypothesized that asymptomatic Parkin mutation carriers would show increased activity in this area during processing of affective facial gestures, replicating the compensatory motor effects that have previously been observed in these individuals. Additionally, Parkin mutation carriers might show altered activity in other basal ganglia-cortical gating loops. Eight asymptomatic heterozygous Parkin mutation carriers and eight matched controls underwent functional magnetic resonance imaging and a subsequent facial emotion recognition task. As predicted, Parkin mutation carriers showed significantly stronger activity in

  20. Decreased premotor cortex volume in victims of urban violence with posttraumatic stress disorder.

    Directory of Open Access Journals (Sweden)

    Vanessa Rocha-Rego

    Full Text Available BACKGROUND: Studies addressing posttraumatic stress disorder (PTSD have demonstrated that PTSD patients exhibit structural abnormalities in brain regions that relate to stress regulation and fear responses, such as the hippocampus, amygdala, anterior cingulate cortex, and ventromedial prefrontal cortex. Premotor cortical areas are involved in preparing to respond to a threatening situation and in representing the peripersonal space. Urban violence is an important and pervasive cause of human suffering, especially in large urban centers in the developing world. Violent events, such as armed robbery, are very frequent in certain cities, and these episodes increase the risk of PTSD. Assaultive trauma is characterized by forceful invasion of the peripersonal space; therefore, could this traumatic event be associated with structural alteration of premotor areas in PTSD? METHODOLOGY/PRINCIPAL FINDINGS: Structural magnetic resonance imaging scans were acquired from a sample of individuals that had been exposed to urban violence. This sample consisted of 16 PTSD patients and 16 age- and gender-matched controls. Psychometric questionnaires differentiated PTSD patients from trauma-exposed controls with regard to PTSD symptoms, affective, and resilience predispositions. Voxel-based morphometric analysis revealed that, compared with controls, the PTSD patients presented significant reductions in gray matter volume in the ventral premotor cortex and in the pregenual anterior cingulate cortex. CONCLUSIONS: Volume reduction in the premotor cortex that is observed in victims of urban violence with PTSD may be associated with a disruption in the dynamical modulation of the safe space around the body. The finding that PTSD patients presented a smaller volume of pregenual anterior cingulate cortex is consistent with the results of other PTSD neuroimaging studies that investigated different types of traumatic events.

  1. Exploring the contributions of premotor and parietal cortex to spatial compatibility using image-guided TMS.

    Science.gov (United States)

    Koski, Lisa; Molnar-Szakacs, Istvan; Iacoboni, Marco

    2005-01-15

    Functional brain imaging studies have demonstrated increased activity in dorsal premotor and posterior parietal cortex when performing spatial stimulus-response compatibility tasks (SRC). We tested the specific role of these regions in stimulus-response mapping using single-pulse transcranial magnetic stimulation (TMS). Subjects were scanned using functional magnetic resonance imaging (fMRI) prior to the TMS session during performance of a task in which spatial compatibility was manipulated. For each subject, the area of increased signal within the regions of interest was registered onto their own high-resolution T1-weighted anatomic scan. TMS was applied to these areas for each subject using a frameless stereotaxic system. Task accuracy and reaction time (RT) were measured during blocks of compatible or incompatible trials and during blocks of real TMS or sham stimulation. On each trial, a single TMS pulse was delivered at 50, 100, 150, or 200 ms after the onset of the stimulus in the left or right visual field. TMS over the left premotor cortex produced various facilitatory effects, depending on the timing of the stimulation. At short intervals, TMS appeared to prime the left dorsal premotor cortex to select a right-hand response more quickly, regardless of stimulus-response compatibility. The strongest effect of stimulation, however, occurred at the 200-ms interval, when TMS facilitated left-hand responses during the incompatible condition. Facilitation of attention to the contralateral visual hemifield was observed during stimulation over the parietal locations. We conclude that the left premotor cortex is one of the cortical regions responsible for overriding automatic stimulus-response associations.

  2. An anatomical and functional topography of human auditory cortical areas

    Directory of Open Access Journals (Sweden)

    Michelle eMoerel

    2014-07-01

    Full Text Available While advances in magnetic resonance imaging (MRI throughout the last decades have enabled the detailed anatomical and functional inspection of the human brain non-invasively, to date there is no consensus regarding the precise subdivision and topography of the areas forming the human auditory cortex. Here, we propose a topography of the human auditory areas based on insights on the anatomical and functional properties of human auditory areas as revealed by studies of cyto- and myelo-architecture and fMRI investigations at ultra-high magnetic field (7 Tesla. Importantly, we illustrate that - whereas a group-based approach to analyze functional (tonotopic maps is appropriate to highlight the main tonotopic axis - the examination of tonotopic maps at single subject level is required to detail the topography of primary and non-primary areas that may be more variable across subjects. Furthermore, we show that considering multiple maps indicative of anatomical (i.e. myelination as well as of functional properties (e.g. broadness of frequency tuning is helpful in identifying auditory cortical areas in individual human brains. We propose and discuss a topography of areas that is consistent with old and recent anatomical post mortem characterizations of the human auditory cortex and that may serve as a working model for neuroscience studies of auditory functions.

  3. An anatomical and functional topography of human auditory cortical areas.

    Science.gov (United States)

    Moerel, Michelle; De Martino, Federico; Formisano, Elia

    2014-01-01

    While advances in magnetic resonance imaging (MRI) throughout the last decades have enabled the detailed anatomical and functional inspection of the human brain non-invasively, to date there is no consensus regarding the precise subdivision and topography of the areas forming the human auditory cortex. Here, we propose a topography of the human auditory areas based on insights on the anatomical and functional properties of human auditory areas as revealed by studies of cyto- and myelo-architecture and fMRI investigations at ultra-high magnetic field (7 Tesla). Importantly, we illustrate that-whereas a group-based approach to analyze functional (tonotopic) maps is appropriate to highlight the main tonotopic axis-the examination of tonotopic maps at single subject level is required to detail the topography of primary and non-primary areas that may be more variable across subjects. Furthermore, we show that considering multiple maps indicative of anatomical (i.e., myelination) as well as of functional properties (e.g., broadness of frequency tuning) is helpful in identifying auditory cortical areas in individual human brains. We propose and discuss a topography of areas that is consistent with old and recent anatomical post-mortem characterizations of the human auditory cortex and that may serve as a working model for neuroscience studies of auditory functions.

  4. Intraoperative identification of the negative motor network during awake surgery to prevent deficit following brain resection in premotor regions.

    Science.gov (United States)

    Rech, F; Duffau, H; Pinelli, C; Masson, A; Roublot, P; Billy-Jacques, A; Brissart, H; Civit, T

    2017-06-01

    Surgical resection in premotor areas can lead to supplementary motor area syndrome as well as a permanent deficit. However, recent findings suggest a putative role of the negative motor network in those dysfunctions. Our objective was to compare the functional results in two groups of adult patients who underwent the resection of a frontal glioma with and without resection of the negative motor networks. Twelve patients (total of 13 surgeries) were selected for awake surgery for a frontal glioma. Negative motor responses were monitored during surgery at the cortical and subcortical levels. Sites eliciting negative motor responses were first identified then spared (n=8) or removed (n=5) upon oncological requirements. In the group with removal of the negative motor network (n=5), all patients presented a complete supplementary motor area syndrome with akinesia and mutism. At 3months, they all presented bimanual coordination dysfunction and fine movement disorders. In the group with preservation of the negative motor network (n=8), all patients presented transient and slight disorders of speech or upper limb, they all recovered completely at 3months. The negative motor network is a part of a modulatory motor network involved in the occurrence of the supplementary motor area syndrome and the permanent deficit after resection in premotor areas. Then, intraoperative functional cortico-subcortical mapping using direct electrostimulation under awake surgery seems mandatory to avoid deficit in bimanual coordination and fine movements during surgery in premotor areas. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  5. Different cortical areas in man in organization of voluntary movements in extrapersonal space

    DEFF Research Database (Denmark)

    Roland, P E; Skinhøj, E; Lassen, N A

    1980-01-01

    CBF in the supplementary motor area (bilaterally), the convexity part of the premotor area (bilaterally), the primary sensorimotor hand and arm area (contralaterally), and in the superior and inferior parietal region (bilaterally). 3. During the maze test there were, in addition, bilateral focal increases of the blood...... in extrapersonal space only are associated with activation of the parietal regions. These areas are assumed to provide information to the motor programming neurons about the demanded direction of motion in extrapersonal space in relation to proprioceptive reference systems. 6. The increase of rCBF in the auditory...

  6. Perceptual learning modifies the functional specializations of visual cortical areas.

    Science.gov (United States)

    Chen, Nihong; Cai, Peng; Zhou, Tiangang; Thompson, Benjamin; Fang, Fang

    2016-05-17

    Training can improve performance of perceptual tasks. This phenomenon, known as perceptual learning, is strongest for the trained task and stimulus, leading to a widely accepted assumption that the associated neuronal plasticity is restricted to brain circuits that mediate performance of the trained task. Nevertheless, learning does transfer to other tasks and stimuli, implying the presence of more widespread plasticity. Here, we trained human subjects to discriminate the direction of coherent motion stimuli. The behavioral learning effect substantially transferred to noisy motion stimuli. We used transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI) to investigate the neural mechanisms underlying the transfer of learning. The TMS experiment revealed dissociable, causal contributions of V3A (one of the visual areas in the extrastriate visual cortex) and MT+ (middle temporal/medial superior temporal cortex) to coherent and noisy motion processing. Surprisingly, the contribution of MT+ to noisy motion processing was replaced by V3A after perceptual training. The fMRI experiment complemented and corroborated the TMS finding. Multivariate pattern analysis showed that, before training, among visual cortical areas, coherent and noisy motion was decoded most accurately in V3A and MT+, respectively. After training, both kinds of motion were decoded most accurately in V3A. Our findings demonstrate that the effects of perceptual learning extend far beyond the retuning of specific neural populations for the trained stimuli. Learning could dramatically modify the inherent functional specializations of visual cortical areas and dynamically reweight their contributions to perceptual decisions based on their representational qualities. These neural changes might serve as the neural substrate for the transfer of perceptual learning.

  7. [Preoperative direct cortical and sub-cortical electric stimulation during cerebral surgery in functional areas].

    Science.gov (United States)

    Duffau, H; Capelle, L; Sichez, J P; Bitar, A; Faillot, T; Arthuis, F; Van Effenterre, R; Fohanno, D

    1999-09-01

    Indications of surgical treatment for lesions in functional cerebral areas depend on the ratio between the definitive neurological deficit and the beneficial effect of resection. Detection of eloquent cortex is difficult because of important individual variability. Peroperative direct cortical and subcortical electrical stimulations (DCS) provide the most precise and reliable method currently available allowing identification and preservation of neurons essential for motricity, sensitivity++ and language. We report our preliminary experience with DCS in surgery of intracerebral infiltrative tumors with a consecutive series of 15 patients operated from November 96 through September 97 in our institution. Presenting symptoms in the 15 patients (8 males, 7 females, mean age 43 years) were seizures in 11 cases (73%) and neurological deficit in 4 cases (27%). Clinical examination was normal in 11 patients and revealed hemiparesia in 4. Magnetic resonance imaging (MRI) with three-dimensional reconstruction showed a precentral tumor in 10 cases, central lesion in one patient, postcentral lesion in two cases, right insular tumor (non-dominant hemisphere) in one case. All patients underwent surgical resection using DCS with detection in 13 cases of motor cortex and subcortical pathways under genera anesthesia, in one case of somatosensory area under local anesthesia, and in one case of language areas also under local anesthesia. The tumor was recurrent in two patients had been operated earlier but without DCS. Resection, verified by postoperative MRI, was total in 12 cases (80%) and estimated at 80% in 3 patients. Histological examination revealed an infiltrative glioma in 12 cases (8 low grade astrocytomas, 3 low grade oligodendrogliomas, and one anaplastic oligodendroglioma), and metastases in 3 cases. Eight patients had no postoperative deficit, while the other 7 patients were impaired, with, in all cases except one, complete recovery in 15 days to 2 months. Direct

  8. A Model for Cortical 40 Hz oscillations invokes inter-area interactions

    DEFF Research Database (Denmark)

    Cotterill, Rodney M J; Helix Nielsen, Claus

    1991-01-01

    COMPUTER simulation of the dynamics of neuronal assemblies within minicolumns, and of the interactions between minicolumns in different cortical areas, has produced a quantitative explanation of the 35-60 Hz oscillations recently observed in adult cat striate cortices. The observed behavior...... suggests an association mechanism that exploits the NMDA receptor's properties. Detectable oscillations are predicted in cortical areas not directly stimulated, provided these are associatively linked with areas receiving sensory input....

  9. Sequences of abstract nonbiological stimuli share ventral premotor cortex with action observation and imagery.

    Science.gov (United States)

    Schubotz, Ricarda I; von Cramon, D Yves

    2004-06-16

    Activation triggered by either observed or imagined actions suggests that the ventral premotor cortex (PMv) provides an action vocabulary that allows us to detect and anticipate basically invariant perceptual states in observed actions. In the present study, we tested the hypothesis that the same PMv region is also recruited by nonbiological (abstract) stimulus sequences as long as the temporal order of stimuli has to be processed. Using functional magnetic resonance imaging, we instructed participants to assess expected outcomes in observed actions [external biological cues (EB)], motor imagery [internal biological cues (IB)], or geometrical figure sequences [external nonbiological cues (EN)]. As hypothesized, we found that each condition elicited significant activation within PMv [left hemisphere, Brodman Area (BA) 6], in contrast to a sequential target detection control task. In addition, cue-specific activations were identified in areas that were only engaged for biologically (action) cued (EB, IB) and nonbiologically cued (EN) tasks. Biologically cued tasks elicited activations within inferior frontal gyri adjacent to PMv (BA 44/45), in the frontomedian wall, the extrastriate body area, posterior superior temporal sulci, somatosensory cortices, and the amygdala-hippocampal-area, whereas the nonbiologically cued task engaged presupplementary motor area, middle frontal gyri, intraparietal sulci, and caudate nuclei of the basal ganglia. In sum, findings point to a basic premotor contribution to the representation or processing of sequentially structured events, supplemented by different sets of areas in the context of either biological or nonbiological cues.

  10. Beta activity in the premotor cortex is increased during stabilized as compared to normal walking

    Directory of Open Access Journals (Sweden)

    Sjoerd M. Bruijn

    2015-10-01

    Full Text Available Walking on two legs is inherently unstable. Still, we humans perform remarkable well at it, mostly without falling. To gain more understanding of the role of the brain in controlling gait stability we measured brain activity using electro-encephalography (EEG during stabilized and normal walking.Subjects walked on a treadmill in two conditions, each lasting 10 minutes; normal, and while being laterally stabilized by elastic cords. Kinematics of trunk and feet, electro-myography (EMG of neck muscles, as well as 64-channel EEG were recorded. To assess gait stability the local divergence exponent, step width, and trunk range of motion were calculated from the kinematic data. We used independent component analysis to remove movement, EMG, and eyeblink artifacts from the EEG, after which dynamic imaging of coherent sources beamformers were determined to identify cortical sources that showed a significant difference between conditions. Stabilized walking led to a significant increase in gait stability, i.e. lower local divergence exponents. Beamforming analysis of the beta band activity revealed significant sources in bilateral pre-motor cortices. Projection of sensor data on these sources showed a significant difference only in the left premotor area, with higher beta power during stabilized walking, specifically around push-off, although only significant around contralateral push-off. It appears that even during steady gait the cortex is involved in the control of stability.

  11. Grasp movement decoding from premotor and parietal cortex.

    Science.gov (United States)

    Townsend, Benjamin R; Subasi, Erk; Scherberger, Hansjörg

    2011-10-05

    Despite recent advances in harnessing cortical motor-related activity to control computer cursors and robotic devices, the ability to decode and execute different grasping patterns remains a major obstacle. Here we demonstrate a simple Bayesian decoder for real-time classification of grip type and wrist orientation in macaque monkeys that uses higher-order planning signals from anterior intraparietal cortex (AIP) and ventral premotor cortex (area F5). Real-time decoding was based on multiunit signals, which had similar tuning properties to cells in previous single-unit recording studies. Maximum decoding accuracy for two grasp types (power and precision grip) and five wrist orientations was 63% (chance level, 10%). Analysis of decoder performance showed that grip type decoding was highly accurate (90.6%), with most errors occurring during orientation classification. In a subsequent off-line analysis, we found small but significant performance improvements (mean, 6.25 percentage points) when using an optimized spike-sorting method (superparamagnetic clustering). Furthermore, we observed significant differences in the contributions of F5 and AIP for grasp decoding, with F5 being better suited for classification of the grip type and AIP contributing more toward decoding of object orientation. However, optimum decoding performance was maximal when using neural activity simultaneously from both areas. Overall, these results highlight quantitative differences in the functional representation of grasp movements in AIP and F5 and represent a first step toward using these signals for developing functional neural interfaces for hand grasping.

  12. Prenatal thalamic waves regulate cortical area size prior to sensory processing

    Science.gov (United States)

    Moreno-Juan, Verónica; Filipchuk, Anton; Antón-Bolaños, Noelia; Mezzera, Cecilia; Gezelius, Henrik; Andrés, Belen; Rodríguez-Malmierca, Luis; Susín, Rafael; Schaad, Olivier; Iwasato, Takuji; Schüle, Roland; Rutlin, Michael; Nelson, Sacha; Ducret, Sebastien; Valdeolmillos, Miguel; Rijli, Filippo M.; López-Bendito, Guillermina

    2017-01-01

    The cerebral cortex is organized into specialized sensory areas, whose initial territory is determined by intracortical molecular determinants. Yet, sensory cortical area size appears to be fine tuned during development to respond to functional adaptations. Here we demonstrate the existence of a prenatal sub-cortical mechanism that regulates the cortical areas size in mice. This mechanism is mediated by spontaneous thalamic calcium waves that propagate among sensory-modality thalamic nuclei up to the cortex and that provide a means of communication among sensory systems. Wave pattern alterations in one nucleus lead to changes in the pattern of the remaining ones, triggering changes in thalamic gene expression and cortical area size. Thus, silencing calcium waves in the auditory thalamus induces Rorβ upregulation in a neighbouring somatosensory nucleus preluding the enlargement of the barrel-field. These findings reveal that embryonic thalamic calcium waves coordinate cortical sensory area patterning and plasticity prior to sensory information processing. PMID:28155854

  13. Functional differentiation of the premotor cortex : Behavioural and brain imaging studies in humans

    NARCIS (Netherlands)

    Potgieser, Adriaan Remco Ewoud

    2015-01-01

    The premotor cortex is a brain structure that is involved in the preparation of movements. It has an important role in the final integration of task-related information and to funnel this to the primary motor cortex, which subsequently causes the execution of a movement. Premotor areas can also infl

  14. Premotor Diagnosis of Parkinson's Disease.

    Science.gov (United States)

    Reichmann, Heinz

    2017-08-03

    Typical Parkinsonian symptoms consist of bradykinesia plus rigidity and/or resting tremor. Some time later postural instability occurs. Pre-motor symptoms such as hyposmia, constipation, REM sleep behavior disorder and depression may antecede these motor symptoms for years. It would be ideal, if we had a biomarker which would allow to predict who with one or two of these pre-motor symptoms will develop the movement disorder Parkinson's disease (PD). Thus, it is interesting to learn that biopsies of the submandibular gland or colon biopsies may be a means to predict PD, if there is a high amout of abnormally folded alpha-synuclein and phosphorylated alpha-synuclein. This would be of relevance if we would have available means to stop the propagation of abnormal alpha-synuclein which is otherwise one of the reasons of this spreading disease PD.

  15. Convergence and divergence are mostly reciprocated properties of the connections in the network of cortical areas.

    Science.gov (United States)

    Négyessy, László; Nepusz, Tamás; Zalányi, László; Bazsó, Fülöp

    2008-10-22

    Cognition is based on the integrated functioning of hierarchically organized cortical processing streams in a manner yet to be clarified. Because integration fundamentally depends on convergence and the complementary notion of divergence of the neuronal connections, we analysed integration by measuring the degree of convergence/divergence through the connections in the network of cortical areas. By introducing a new index, we explored the complementary convergent and divergent nature of connectional reciprocity and delineated the backward and forward cortical sub-networks for the first time. Integrative properties of the areas defined by the degree of convergence/divergence through their afferents and efferents exhibited distinctive characteristics at different levels of the cortical hierarchy. Areas previously identified as hubs exhibit information bottleneck properties. Cortical networks largely deviate from random graphs where convergence and divergence are balanced at low reciprocity level. In the cortex, which is dominated by reciprocal connections, balance appears only by further increasing the number of reciprocal connections. The results point to the decisive role of the optimal number and placement of reciprocal connections in large-scale cortical integration. Our findings also facilitate understanding of the functional interactions between the cortical areas and the information flow or its equivalents in highly recurrent natural and artificial networks.

  16. Cortical control of facial expression.

    Science.gov (United States)

    Müri, René M

    2016-06-01

    The present Review deals with the motor control of facial expressions in humans. Facial expressions are a central part of human communication. Emotional face expressions have a crucial role in human nonverbal behavior, allowing a rapid transfer of information between individuals. Facial expressions can be either voluntarily or emotionally controlled. Recent studies in nonhuman primates and humans have revealed that the motor control of facial expressions has a distributed neural representation. At least five cortical regions on the medial and lateral aspects of each hemisphere are involved: the primary motor cortex, the ventral lateral premotor cortex, the supplementary motor area on the medial wall, and the rostral and caudal cingulate cortex. The results of studies in humans and nonhuman primates suggest that the innervation of the face is bilaterally controlled for the upper part and mainly contralaterally controlled for the lower part. Furthermore, the primary motor cortex, the ventral lateral premotor cortex, and the supplementary motor area are essential for the voluntary control of facial expressions. In contrast, the cingulate cortical areas are important for emotional expression, because they receive input from different structures of the limbic system.

  17. Cortical thickness and surface area in neonates at high risk for schizophrenia.

    Science.gov (United States)

    Li, Gang; Wang, Li; Shi, Feng; Lyall, Amanda E; Ahn, Mihye; Peng, Ziwen; Zhu, Hongtu; Lin, Weili; Gilmore, John H; Shen, Dinggang

    2016-01-01

    Schizophrenia is a neurodevelopmental disorder associated with subtle abnormal cortical thickness and cortical surface area. However, it is unclear whether these abnormalities exist in neonates associated with genetic risk for schizophrenia. To this end, this preliminary study was conducted to identify possible abnormalities of cortical thickness and surface area in the high-genetic-risk neonates. Structural magnetic resonance images were acquired from offspring of mothers (N = 21) who had schizophrenia (N = 12) or schizoaffective disorder (N = 9), and also matched healthy neonates of mothers who were free of psychiatric illness (N = 26). Neonatal cortical surfaces were reconstructed and parcellated as regions of interest (ROIs), and cortical thickness for each vertex was computed as the shortest distance between the inner and outer surfaces. Comparisons were made for the average cortical thickness and total surface area in each of 68 cortical ROIs. After false discovery rate (FDR) correction, it was found that the female high-genetic-risk neonates had significantly thinner cortical thickness in the right lateral occipital cortex than the female control neonates. Before FDR correction, the high-genetic-risk neonates had significantly thinner cortex in the left transverse temporal gyrus, left banks of superior temporal sulcus, left lingual gyrus, right paracentral cortex, right posterior cingulate cortex, right temporal pole, and right lateral occipital cortex, compared with the control neonates. Before FDR correction, in comparison with control neonates, male high-risk neonates had significantly thicker cortex in the left frontal pole, left cuneus cortex, and left lateral occipital cortex; while female high-risk neonates had significantly thinner cortex in the bilateral paracentral, bilateral lateral occipital, left transverse temporal, left pars opercularis, right cuneus, and right posterior cingulate cortices. The high-risk neonates also had significantly

  18. Distribution of neurons in functional areas of the mouse cerebral cortex reveals quantitatively different cortical zones.

    Science.gov (United States)

    Herculano-Houzel, Suzana; Watson, Charles; Paxinos, George

    2013-01-01

    How are neurons distributed along the cortical surface and across functional areas? Here we use the isotropic fractionator (Herculano-Houzel and Lent, 2005) to analyze the distribution of neurons across the entire isocortex of the mouse, divided into 18 functional areas defined anatomically. We find that the number of neurons underneath a surface area (the N/A ratio) varies 4.5-fold across functional areas and neuronal density varies 3.2-fold. The face area of S1 contains the most neurons, followed by motor cortex and the primary visual cortex. Remarkably, while the distribution of neurons across functional areas does not accompany the distribution of surface area, it mirrors closely the distribution of cortical volumes-with the exception of the visual areas, which hold more neurons than expected for their volume. Across the non-visual cortex, the volume of individual functional areas is a shared linear function of their number of neurons, while in the visual areas, neuronal densities are much higher than in all other areas. In contrast, the 18 functional areas cluster into three different zones according to the relationship between the N/A ratio and cortical thickness and neuronal density: these three clusters can be called visual, sensory, and, possibly, associative. These findings are remarkably similar to those in the human cerebral cortex (Ribeiro et al., 2013) and suggest that, like the human cerebral cortex, the mouse cerebral cortex comprises two zones that differ in how neurons form the cortical volume, and three zones that differ in how neurons are distributed underneath the cortical surface, possibly in relation to local differences in connectivity through the white matter. Our results suggest that beyond the developmental divide into visual and non-visual cortex, functional areas initially share a common distribution of neurons along the parenchyma that become delimited into functional areas according to the pattern of connectivity established later.

  19. Regional brain differences in cortical thickness, surface area and subcortical volume in individuals with Williams syndrome.

    Science.gov (United States)

    Meda, Shashwath A; Pryweller, Jennifer R; Thornton-Wells, Tricia A

    2012-01-01

    Williams syndrome (WS) is a rare genetic neurodevelopmental disorder characterized by increased non-social anxiety, sensitivity to sounds and hypersociability. Previous studies have reported contradictory findings with regard to regional brain variation in WS, relying on only one type of morphological measure (usually volume) in each study. The present study aims to contribute to this body of literature and perhaps elucidate some of these discrepancies by examining concurrent measures of cortical thickness, surface area and subcortical volume between WS subjects and typically-developing (TD) controls. High resolution MRI scans were obtained on 31 WS subjects and 50 typically developing control subjects. We derived quantitative regional estimates of cortical thickness, cortical surface area, and subcortical volume using FreeSurfer software. We evaluated between-group ROI differences while controlling for total intracranial volume. In post-hoc exploratory analyses within the WS group, we tested for correlations between regional brain variation and Beck Anxiety Inventory scores. Consistent with our hypothesis, we detected complex patterns of between-group cortical variation, which included lower surface area in combination with greater thickness in the following cortical regions: post central gyrus, cuneus, lateral orbitofrontal cortex and lingual gyrus. Additional cortical regions showed between-group differences in one (but not both) morphological measures. Subcortical volume was lower in the basal ganglia and the hippocampus in WS versus TD controls. Exploratory correlations revealed that anxiety scores were negatively correlated with gray matter surface area in insula, OFC, rostral middle frontal, superior temporal and lingual gyrus. Our results were consistent with previous reports showing structural alterations in regions supporting the socio-affective and visuospatial impairments in WS. However, we also were able to effectively capture novel and complex

  20. Regional brain differences in cortical thickness, surface area and subcortical volume in individuals with Williams syndrome.

    Directory of Open Access Journals (Sweden)

    Shashwath A Meda

    Full Text Available Williams syndrome (WS is a rare genetic neurodevelopmental disorder characterized by increased non-social anxiety, sensitivity to sounds and hypersociability. Previous studies have reported contradictory findings with regard to regional brain variation in WS, relying on only one type of morphological measure (usually volume in each study. The present study aims to contribute to this body of literature and perhaps elucidate some of these discrepancies by examining concurrent measures of cortical thickness, surface area and subcortical volume between WS subjects and typically-developing (TD controls. High resolution MRI scans were obtained on 31 WS subjects and 50 typically developing control subjects. We derived quantitative regional estimates of cortical thickness, cortical surface area, and subcortical volume using FreeSurfer software. We evaluated between-group ROI differences while controlling for total intracranial volume. In post-hoc exploratory analyses within the WS group, we tested for correlations between regional brain variation and Beck Anxiety Inventory scores. Consistent with our hypothesis, we detected complex patterns of between-group cortical variation, which included lower surface area in combination with greater thickness in the following cortical regions: post central gyrus, cuneus, lateral orbitofrontal cortex and lingual gyrus. Additional cortical regions showed between-group differences in one (but not both morphological measures. Subcortical volume was lower in the basal ganglia and the hippocampus in WS versus TD controls. Exploratory correlations revealed that anxiety scores were negatively correlated with gray matter surface area in insula, OFC, rostral middle frontal, superior temporal and lingual gyrus. Our results were consistent with previous reports showing structural alterations in regions supporting the socio-affective and visuospatial impairments in WS. However, we also were able to effectively capture novel and

  1. Space-dependent representation of objects and other's action in monkey ventral premotor grasping neurons.

    Science.gov (United States)

    Bonini, Luca; Maranesi, Monica; Livi, Alessandro; Fogassi, Leonardo; Rizzolatti, Giacomo

    2014-03-12

    The macaque ventral premotor area F5 hosts two types of visuomotor grasping neurons: "canonical" neurons, which respond to visually presented objects and underlie visuomotor transformation for grasping, and "mirror" neurons, which respond during the observation of others' action, likely playing a role in action understanding. Some previous evidence suggested that canonical and mirror neurons could be anatomically segregated in different sectors of area F5. Here we investigated the functional properties of single neurons in the hand field of area F5 using various tasks similar to those originally designed to investigate visual responses to objects and actions. By using linear multielectrode probes, we were able to simultaneously record different types of neurons and to precisely localize their cortical depth. We recorded 464 neurons, of which 243 showed visuomotor properties. Canonical and mirror neurons were often present in the same cortical sites; and, most interestingly, a set of neurons showed both canonical and mirror properties, discharging to object presentation as well as during the observation of experimenter's goal-directed acts (canonical-mirror neurons). Typically, visual responses to objects were constrained to the monkey peripersonal space, whereas action observation responses were less space-selective. Control experiments showed that space-constrained coding of objects mostly relies on an operational (action possibility) rather than metric (absolute distance) reference frame. Interestingly, canonical-mirror neurons appear to code object as target for both one's own and other's action, suggesting that they could play a role in predictive representation of others' impending actions.

  2. Dynamic Development of Regional Cortical Thickness and Surface Area in Early Childhood.

    Science.gov (United States)

    Lyall, Amanda E; Shi, Feng; Geng, Xiujuan; Woolson, Sandra; Li, Gang; Wang, Li; Hamer, Robert M; Shen, Dinggang; Gilmore, John H

    2015-08-01

    Cortical thickness (CT) and surface area (SA) are altered in many neuropsychiatric disorders and are correlated with cognitive functioning. Little is known about how these components of cortical gray matter develop in the first years of life. We studied the longitudinal development of regional CT and SA expansion in healthy infants from birth to 2 years. CT and SA have distinct and heterogeneous patterns of development that are exceptionally dynamic; overall CT increases by an average of 36.1%, while cortical SA increases 114.6%. By age 2, CT is on average 97% of adult values, compared with SA, which is 69%. This suggests that early identification, prevention, and intervention strategies for neuropsychiatric illness need to be targeted to this period of rapid postnatal brain development, and that SA expansion is the principal driving factor in cortical volume after 2 years of age.

  3. Probing region-specific microstructure of human cortical areas using high angular and spatial resolution diffusion MRI.

    Science.gov (United States)

    Aggarwal, Manisha; Nauen, David W; Troncoso, Juan C; Mori, Susumu

    2015-01-15

    Regional heterogeneity in cortical cyto- and myeloarchitecture forms the structural basis of mapping of cortical areas in the human brain. In this study, we investigate the potential of diffusion MRI to probe the microstructure of cortical gray matter and its region-specific heterogeneity across cortical areas in the fixed human brain. High angular resolution diffusion imaging (HARDI) data at an isotropic resolution of 92-μm and 30 diffusion-encoding directions were acquired using a 3D diffusion-weighted gradient-and-spin-echo sequence, from prefrontal (Brodmann area 9), primary motor (area 4), primary somatosensory (area 3b), and primary visual (area 17) cortical specimens (n=3 each) from three human subjects. Further, the diffusion MR findings in these cortical areas were compared with histological silver impregnation of the same specimens, in order to investigate the underlying architectonic features that constitute the microstructural basis of diffusion-driven contrasts in cortical gray matter. Our data reveal distinct and region-specific diffusion MR contrasts across the studied areas, allowing delineation of intracortical bands of tangential fibers in specific layers-layer I, layer VI, and the inner and outer bands of Baillarger. The findings of this work demonstrate unique sensitivity of diffusion MRI to differentiate region-specific cortical microstructure in the human brain, and will be useful for myeloarchitectonic mapping of cortical areas as well as to achieve an understanding of the basis of diffusion NMR contrasts in cortical gray matter. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Implied Motion Activation in Cortical Area MT Can Be Explained by Visual Low-level Features

    NARCIS (Netherlands)

    Lorteije, Jeannette A.M.; Barraclough, Nick E.; Jellema, Tjeerd; Raemaekers, Mathijs; Duijnhouwer, Jacob; Xiao, Dengke; Oram, Mike W.; Lankheet, Martin J.M.; Perrett, David I.; van Wezel, Richard Jack Anton

    To investigate form-related activity in motion-sensitive cortical areas, we recorded cell responses to animate implied motion in macaque middle temporal (MT) and medial superior temporal (MST) cortex and investigated these areas using fMRI in humans. In the single-cell studies, we compared responses

  5. Dynamics of brain activity in motor and frontal cortical areas during music listening: a magnetoencephalographic study.

    Science.gov (United States)

    Popescu, Mihai; Otsuka, Asuka; Ioannides, Andreas A

    2004-04-01

    There are formidable problems in studying how 'real' music engages the brain over wide ranges of temporal scales extending from milliseconds to a lifetime. In this work, we recorded the magnetoencephalographic signal while subjects listened to music as it unfolded over long periods of time (seconds), and we developed and applied methods to correlate the time course of the regional brain activations with the dynamic aspects of the musical sound. We showed that frontal areas generally respond with slow time constants to the music, reflecting their more integrative mode; motor-related areas showed transient-mode responses to fine temporal scale structures of the sound. The study combined novel analysis techniques designed to capture and quantify fine temporal sequencing from the authentic musical piece (characterized by a clearly defined rhythm and melodic structure) with the extraction of relevant features from the dynamics of the regional brain activations. The results demonstrated that activity in motor-related structures, specifically in lateral premotor areas, supplementary motor areas, and somatomotor areas, correlated with measures of rhythmicity derived from the music. These correlations showed distinct laterality depending on how the musical performance deviated from the strict tempo of the music score, that is, depending on the musical expression.

  6. Decision-making in the ventral premotor cortex harbinger of action

    Directory of Open Access Journals (Sweden)

    José L. ePardo-Vázquez

    2011-09-01

    Full Text Available Although the premotor cortex (PM was once viewed as the substrate of pure motor functions, soon it was realized that it was involved in higher brain functions. By this it is meant that the PM cortex functions would better be explained as motor set, preparation for limb movement or sensory guidance of movement rather than solely by a fixed link to motor performance. These findings, together with a better knowledge of the PM cortex histology and hodology in human and non-human primates prompted quantitative studies of this area combining behavioral tasks with electrophysiological recordings. In addition, the exploration of the PM cortex neurons with qualitative methods also suggested its participation in higher functions. Behavioral choices frequently depend on temporal cues, which together with knowledge of previous outcomes and expectancies are combined to decide and choose a behavioral action. In decision-making the knowledge about the consequences of decisions, either correct or incorrect, is fundamental because they can be used to adapt future behavior. The neuronal correlates of a decision process have been described in several cortical areas of primates. Among them, there is evidence that the monkey ventral premotor cortex (PMv, an anatomical and physiological well-differentiated area of the PM cortex, supports both perceptual decisions and performance monitoring. Here we review the evidence that the steps in a decision making process are encoded in the firing rate of the PMv neurons. This provides compelling evidence suggesting that the PMv is involved in the use of recent and long-term sensory memory to decide, execute and evaluate the outcomes of the subjects’ choices.

  7. Loss of nonphosphorylated neurofilament immunoreactivity in temporal cortical areas in Alzheimer's disease.

    Science.gov (United States)

    Thangavel, R; Sahu, S K; Van Hoesen, G W; Zaheer, A

    2009-05-05

    The distribution of immunoreactive neurons with nonphosphorylated neurofilament protein (SMI32) was studied in temporal cortical areas in normal subjects and in patients with Alzheimer's disease (AD). SMI32 immunopositive neurons were localized mainly in cortical layers II, III, V and VI, and were medium to large-sized pyramidal neurons. Patients with AD had prominent degeneration of SMI32 positive neurons in layers III and V of Brodmann areas 38, 36, 35 and 20; in layers II and IV of the entorhinal cortex (Brodmann area 28); and hippocampal neurons. Neurofibrillary tangles (NFTs) were stained with Thioflavin-S and with an antibody (AT8) against hyperphosphorylated tau. The NFT distribution was compared to that of the neuronal cytoskeletal marker SMI32 in these temporal cortical regions. The results showed that the loss of SMI32 immunoreactivity in temporal cortical regions of AD brain is paralleled by an increase in NFTs and AT8 immunoreactivity in neurons. The SMI32 immunoreactivity was drastically reduced in the cortical layers where tangle-bearing neurons are localized. A strong SMI32 immunoreactivity was observed in numerous neurons containing NFTs by double-immunolabeling with SMI32 and AT8. However, few neurons were labeled by AT8 and SMI32. These results suggest that the development of NFTs in some neurons results from some alteration in SMI32 expression, but does not account for all, particularly, early NFT-related changes. Also, there is a clear correlation of NFTs with selective population of pyramidal neurons in the temporal cortical areas and these pyramidal cells are specifically prone to formation of paired helical filaments. Furthermore, these pyramidal neurons might represent a significant portion of the neurons of origin of long corticocortical connection, and consequently contribute to the destruction of memory-related input to the hippocampal formation.

  8. Interhemispheric claustral circuits coordinate somatomotor and visuomotor cortical areas that regulate exploratory behaviors

    Directory of Open Access Journals (Sweden)

    Jared Brent Smith

    2014-05-01

    Full Text Available The claustrum has a role in the interhemispheric transfer of certain types of sensorimotor information. Whereas the whisker region in rat motor (M1 cortex sends dense projections to the contralateral claustrum, the M1 forelimb representation does not. The claustrum sends strong ipsilateral projections to the whisker regions in M1 and somatosensory (S1 cortex, but its projections to the forelimb cortical areas are weak. These distinctions suggest that one function of the M1 projections to the contralateral claustrum is to coordinate the cortical areas that regulate peripheral sensor movements during behaviors that depend on bilateral sensory acquisition. If this hypothesis is true, then similar interhemispheric circuits should interconnect the frontal eye fields (FEF with the contralateral claustrum and its network of projections to vision-related cortical areas. To test this hypothesis, anterograde and retrograde tracers were placed in physiologically-defined parts of the FEF and primary visual cortex (V1 in rats. We observed dense FEF projections to the contralateral claustrum that terminated in the midst of claustral neurons that project to both FEF and V1. While the FEF inputs to the claustrum come predominantly from the contralateral hemisphere, the claustral projections to FEF and V1 are primarily ipsilateral. Detailed comparison of the present results with our previous studies on somatomotor claustral circuitry revealed a well-defined functional topography in which the ventral claustrum is connected with visuomotor cortical areas and the dorsal regions are connected with somatomotor areas. These results suggest that subregions within the claustrum play a critical role in coordinating the cortical areas that regulate the acquisition of modality-specific sensory information during exploration and other behaviors that require sensory attention.

  9. Evidence of functional connectivity between auditory cortical areas revealed by amplitude modulation sound processing.

    Science.gov (United States)

    Guéguin, Marie; Le Bouquin-Jeannès, Régine; Faucon, Gérard; Chauvel, Patrick; Liégeois-Chauvel, Catherine

    2007-02-01

    The human auditory cortex includes several interconnected areas. A better understanding of the mechanisms involved in auditory cortical functions requires a detailed knowledge of neuronal connectivity between functional cortical regions. In human, it is difficult to track in vivo neuronal connectivity. We investigated the interarea connection in vivo in the auditory cortex using a method of directed coherence (DCOH) applied to depth auditory evoked potentials (AEPs). This paper presents simultaneous AEPs recordings from insular gyrus (IG), primary and secondary cortices (Heschl's gyrus and planum temporale), and associative areas (Brodmann area [BA] 22) with multilead intracerebral electrodes in response to sinusoidal modulated white noises in 4 epileptic patients who underwent invasive monitoring with depth electrodes for epilepsy surgery. DCOH allowed estimation of the causality between 2 signals recorded from different cortical sites. The results showed 1) a predominant auditory stream within the primary auditory cortex from the most medial region to the most lateral one whatever the modulation frequency, 2) unidirectional functional connection from the primary to secondary auditory cortex, 3) a major auditory propagation from the posterior areas to the anterior ones, particularly at 8, 16, and 32 Hz, and 4) a particular role of Heschl's sulcus dispatching information to the different auditory areas. These findings suggest that cortical processing of auditory information is performed in serial and parallel streams. Our data showed that the auditory propagation could not be associated to a unidirectional traveling wave but to a constant interaction between these areas that could reflect the large adaptive and plastic capacities of auditory cortex. The role of the IG is discussed.

  10. Interhemispheric Connections between the Primary Visual Cortical Areas via the Anterior Commissure in Human Callosal Agenesis.

    Science.gov (United States)

    van Meer, Nathalie; Houtman, Anne C; Van Schuerbeek, Peter; Vanderhasselt, Tim; Milleret, Chantal; Ten Tusscher, Marcel P

    2016-01-01

    Aim: In humans, images in the median plane of the head either fall on both nasal hemi-retinas or on both temporal hemi-retinas. Interhemispheric connections allow cortical cells to have receptive fields on opposite sides. The major interhemispheric connection, the corpus callosum, is implicated in central stereopsis and disparity detection in front of the fixation plane. Yet individuals with agenesis of the corpus callosum may show normal stereopsis and disparity vergence. We set out to study a possible interhemispheric connection between primary visual cortical areas via the anterior commissure to explain this inconsistency because of the major role of these cortical areas in elaborating 3D visual perception. Methods: MRI, DTI and tractography of the brain of a 53-year old man with complete callosal agenesis and normal binocular single vision was undertaken. Tractography seed points were placed in both the right and the left V1 and V2. Nine individuals with both an intact corpus callosum and normal binocularity served as controls. Results: Interhemispheric tracts through the anterior commissure linking both V1 and V2 visual cortical areas bilaterally were indeed shown in the subject with callosal agenesis. All other individuals showed interhemispheric visual connections through the corpus callosum only. Conclusion: Callosal agenesis may result in anomalous interhemispheric connections of the primary visual areas via the anterior commissure. It is proposed here that these connections form as alternative to the normal callosal pathway and may participate in binocularity.

  11. Reduced cortical thickness of brain areas involved in pain processing in patients with chronic pancreatitis.

    NARCIS (Netherlands)

    Frokjaer, J.B.; Bouwense, S.A.W.; Olesen, S.S.; Lundager, F.H.; Eskildsen, S.F.; Goor, H. van; Wilder-Smith, O.H.G.; Drewes, A.M.

    2012-01-01

    BACKGROUND & AIMS: Patients with painful chronic pancreatitis (CP) might have abnormal brain function. We assessed cortical thickness in brain areas involved in visceral pain processing. METHODS: We analyzed brain morphologies of 19 patients with painful CP and compared them with 15 healthy individu

  12. Cortical silent period following TMS in a patient with supplementary sensorimotor area seizures.

    Science.gov (United States)

    Nardone, Raffaele; Venturi, Alessandro; Ausserer, Harald; Ladurner, Günther; Tezzon, Frediano

    2008-01-01

    The cortical silent period (CSP) following transcranial magnetic stimulation (TMS) was evaluated in a patient with a dysembrioplastic neuroepithelial tumor (DNET) in the lateral portion of the right superior frontal gyrus (SFG) who suffered from supplementary sensorimotor area (SSMA) seizures. CSP duration was shortened on the affected side. Ipsilateral alterations of motor cortex excitability with TMS in epileptogenic DNET located outside the PMA argue in favour of cortico-cortical connections to primary motor cortex from SSMA. This functional connectivity should be taken into consideration to better understand the pathophysiology of ictal motor manifestations.

  13. Millisecond-Scale Motor Encoding in a Cortical Vocal Area

    Science.gov (United States)

    Nemenman, Ilya; Tang, Claire; Chehayeb, Diala; Srivastava, Kyle; Sober, Samuel

    2015-03-01

    Studies of motor control have almost universally examined firing rates to investigate how the brain shapes behavior. In principle, however, neurons could encode information through the precise temporal patterning of their spike trains as well as (or instead of) through their firing rates. Although the importance of spike timing has been demonstrated in sensory systems, it is largely unknown whether timing differences in motor areas could affect behavior. We tested the hypothesis that significant information about trial-by-trial variations in behavior is represented by spike timing in the songbird vocal motor system. We found that neurons in motor cortex convey information via spike timing far more often than via spike rate and that the amount of information conveyed at the millisecond timescale greatly exceeds the information available from spike counts. These results demonstrate that information can be represented by spike timing in motor circuits and suggest that timing variations evoke differences in behavior. This work was supported in part by the National Institutes of Health, National Science Foundation, and James S. McDonnell Foundation

  14. A synergy-based hand control is encoded in human motor cortical areas.

    Science.gov (United States)

    Leo, Andrea; Handjaras, Giacomo; Bianchi, Matteo; Marino, Hamal; Gabiccini, Marco; Guidi, Andrea; Scilingo, Enzo Pasquale; Pietrini, Pietro; Bicchi, Antonio; Santello, Marco; Ricciardi, Emiliano

    2016-02-15

    How the human brain controls hand movements to carry out different tasks is still debated. The concept of synergy has been proposed to indicate functional modules that may simplify the control of hand postures by simultaneously recruiting sets of muscles and joints. However, whether and to what extent synergic hand postures are encoded as such at a cortical level remains unknown. Here, we combined kinematic, electromyography, and brain activity measures obtained by functional magnetic resonance imaging while subjects performed a variety of movements towards virtual objects. Hand postural information, encoded through kinematic synergies, were represented in cortical areas devoted to hand motor control and successfully discriminated individual grasping movements, significantly outperforming alternative somatotopic or muscle-based models. Importantly, hand postural synergies were predicted by neural activation patterns within primary motor cortex. These findings support a novel cortical organization for hand movement control and open potential applications for brain-computer interfaces and neuroprostheses.

  15. Cerebral pathological and compensatory mechanisms in the premotor phase of leucine-rich repeat kinase 2 parkinsonism.

    Science.gov (United States)

    van Nuenen, Bart F L; Helmich, Rick C; Ferraye, Murielle; Thaler, Avner; Hendler, Talma; Orr-Urtreger, Avi; Mirelman, Anat; Bressman, Susan; Marder, Karen S; Giladi, Nir; van de Warrenburg, Bart P C; Bloem, Bastiaan R; Toni, Ivan

    2012-12-01

    Compensatory cerebral mechanisms can delay motor symptom onset in Parkinson's disease. We aim to characterize these compensatory mechanisms and early disease-related changes by quantifying movement-related cerebral function in subjects at significantly increased risk of developing Parkinson's disease, namely carriers of a leucine-rich repeat kinase 2-G2019S mutation associated with dominantly inherited parkinsonism. Functional magnetic resonance imaging was used to examine cerebral activity evoked during internal selection of motor representations, a core motor deficit in clinically overt Parkinson's disease. Thirty-nine healthy first-degree relatives of Ashkenazi Jewish patients with Parkinson's disease, who carry the leucine-rich repeat kinase 2-G2019S mutation, participated in this study. Twenty-one carriers of the leucine-rich repeat kinase 2-G2019S mutation and 18 non-carriers of this mutation were engaged in a motor imagery task (laterality judgements of left or right hands) known to be sensitive to motor control parameters. Behavioural performance of both groups was matched. Mutation carriers and non-carriers were equally sensitive to the extent and biomechanical constraints of the imagined movements in relation to the current posture of the participants' hands. Cerebral activity differed between groups, such that leucine-rich repeat kinase 2-G2019S carriers had reduced imagery-related activity in the right caudate nucleus and increased activity in the right dorsal premotor cortex. More severe striatal impairment was associated with stronger effective connectivity between the right dorsal premotor cortex and the right extrastriate body area. These findings suggest that altered movement-related activity in the caudate nuclei of leucine-rich repeat kinase 2-G2019S carriers might remain behaviourally latent by virtue of cortical compensatory mechanisms involving long-range connectivity between the dorsal premotor cortex and posterior sensory regions. These

  16. A proposed number system for the 107 cortical areas of Economo and Koskinas, and Brodmann area correlations.

    Science.gov (United States)

    Triarhou, Lazaros C

    2007-01-01

    In their Atlas of Cytoarchitectonics of the Adult Human Cerebral Cortex, Economo and Koskinas defined 54 'ground,' 76 'variant,' and 107 'modification' areas. The 107 modifications are topographically distributed as 35 frontal, 13 superior limbic, 6 insular, 18 parietal, 7 occipital, 14 temporal and 14 inferior limbic (or hippocampal). One way to make the Economo-Koskinas system more practical is to encode the complex symbol notations of the 107 cortical areas with numbers EK 1 through EK 107. The present study does that, and it further correlates Economo-Koskinas areas with Brodmann areas, based on an overview of the classical and modern neurohistological literature. Copyright (c) 2007 S. Karger AG, Basel.

  17. Anomia produced by direct cortical stimulation of the pre-supplementary motor area in a patient undergoing preoperative language mapping.

    Science.gov (United States)

    Rozanski, Verena Eveline; Peraud, Aurelia; Noachtar, Soheyl

    2015-06-01

    There is sparse data on the analysis of supplementary motor area in language function using direct cortical stimulation of the supplementary motor area. Here, we report a patient who experienced isolated anomia during stimulation of the anterior supplementary motor area and discuss the role of the supplementary motor area in speech production. The role of the pre-supplementary motor· area in word selection, observed in fMRI studies, can be confirmed by direct cortical stimulation.

  18. Cortical modulation of short-latency TMS-evoked potentials

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    Domenica eVeniero

    2013-01-01

    Full Text Available Transcranial magnetic stimulation - electroencephalogram (TMS-EEG co-registration offers the opportunity to test reactivity of brain areas across distinct conditions through TMS-evoked potentials (TEPs. Several TEPs have been described, their functional meaning being largely unknown. In particular, short-latency potentials peaking at 5 (P5 and 8 (N8 ms after the TMS pulse have been recently described, but because of their huge amplitude, the problem of whether their origin is cortical or not has been opened. To gain information about these components, we employed a protocol that modulates primary motor cortex excitability (MI through an exclusively cortical phenomena: low frequency stimulation of premotor area (PMC. TMS was applied simultaneously with EEG recording from 70 electrodes. Amplitude of TEPs evoked by 200 single-pulses TMS delivered over MI at 110% of resting motor threshold was measured before and after applying 900 TMS conditioning stimuli to left premotor cortex with 1 Hz repetition rate. Single subject analyses showed reduction in TEPs amplitude after PMC conditioning in a sample of participants and increase in TEPs amplitude in two subjects. No effects were found on corticospinal excitability as recorded by motor evoked potentials (MEPs. Furthermore, correlation analysis showed an inverse relation between the effects of the conditioning protocol on P5-N8 complex amplitude and MEPs amplitude. Because the effects of the used protocol have been ascribed to a cortical interaction between premotor area and MI, we suggest that despite the sign of P5-N8 amplitude modulation is not consistent across participant, this modulation could indicate, at least in part, their cortical origin. We conclude that with an accurate experimental procedure early-latency components can be used to evaluate the reactivity of the stimulated cortex.

  19. Evidence for visual cortical area homologs in cat and macaque monkey.

    Science.gov (United States)

    Payne, B R

    1993-01-01

    The maps of visuotopically discrete visual cerebral cortical areas in the cat and the macaque monkey are compared and gaps in knowledge are identified that limit such comparisons. Cat areas 17, 18, and 19 can be equated with macaque areas V1, V2, and V3, respectively, based on criteria of relative position in the cortical mantle, internal organization of visual field representations, and trans- and subcortical connections. Using these same criteria, a visual area on the medial bank of the lateral suprasylvian sulcus (area PMLS) in the cat can be equated with macaque area V5. The equivalences are supported by data on neuronal receptive field properties and the contributions the areas make to visual behavior. Although the data are scanty for most other visual areas, there are enough data tentatively to equate collectively cat areas 20a and 20b with macaque areas TF and TH and to liken cat areas 21a and 21b with macaque area V4. What is not clear is if there is a region in cat that is equivalent to area TE in the macaque monkey. If there is, it likely lies on the banks of the posterior suprasylvian sulcus between areas 20 and 21 and the polysensory cortex of the posterior ectosylvian gyrus. Knowledge gained from prior research on macaque areas V4 and TE can be used to formulate specific additional investigations of cat area 21 and the uncharted posterior suprasylvian sulcus. In addition, prior investigations carried out on cat area 20 can be used to devise specific explorations of macaque areas TF and TH.

  20. Cortical Thickness, Surface Area and Subcortical Volume Differentially Contribute to Cognitive Heterogeneity in Parkinson's Disease.

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    Niels J H M Gerrits

    Full Text Available Parkinson's disease (PD is often associated with cognitive deficits, although their severity varies considerably between patients. Recently, we used voxel-based morphometry (VBM to show that individual differences in gray matter (GM volume relate to cognitive heterogeneity in PD. VBM does, however, not differentiate between cortical thickness (CTh and surface area (SA, which might be independently affected in PD. We therefore re-analyzed our cohort using the surface-based method FreeSurfer, and investigated (i CTh, SA, and (subcortical GM volume differences between 93 PD patients and 45 matched controls, and (ii the relation between these structural measures and cognitive performance on six neuropsychological tasks within the PD group. We found cortical thinning in PD patients in the left pericalcarine gyrus, extending to cuneus, precuneus and lingual areas and left inferior parietal cortex, bilateral rostral middle frontal cortex, and right cuneus, and increased cortical surface area in the left pars triangularis. Within the PD group, we found negative correlations between (i CTh of occipital areas and performance on a verbal memory task, (ii SA and volume of the frontal cortex and visuospatial memory performance, and, (iii volume of the right thalamus and scores on two verbal fluency tasks. Our primary findings illustrate that i CTh and SA are differentially affected in PD, and ii VBM and FreeSurfer yield non-overlapping results in an identical dataset. We argue that this discrepancy is due to technical differences and the subtlety of the PD-related structural changes.

  1. An approach for parcellating human cortical areas using resting-state correlations.

    Science.gov (United States)

    Wig, Gagan S; Laumann, Timothy O; Petersen, Steven E

    2014-06-01

    Resting State Functional Connectivity (RSFC) reveals properties related to the brain's underlying organization and function. Features related to RSFC signals, such as the locations where the patterns of RSFC exhibit abrupt transitions, can be used to identify putative boundaries between cortical areas (RSFC-Boundary Mapping). The locations of RSFC-based area boundaries are consistent across independent groups of subjects. RSFC-based parcellation converges with parcellation information from other modalities in many locations, including task-evoked activity and probabilistic estimates of cellular architecture, providing evidence for the ability of RSFC to parcellate brain structures into functionally meaningful units. We not only highlight a collection of these observations, but also point out several limitations and observations that mandate careful consideration in using and interpreting RSFC for the purposes of parcellating the brain's cortical and subcortical structures.

  2. Cortical dysfunction of the supplementary motor area in a spasmodic dysphonia patient.

    Science.gov (United States)

    Hirano, S; Kojima, H; Naito, Y; Tateya, I; Shoji, K; Kaneko, K; Inoue, M; Nishizawa, S; Konishi, J

    2001-01-01

    The etiology of spasmodic dysphonia (SD) is still unknown. In the present study, cortical function of a 59-year-old male patient with adductor type SD was examined during phonation with positron emission tomography (PET). Magnetic resonance imaging showed no organic abnormality in the brain. However, PET showed remarkable activities during phonation in the left motor cortex, Broca's area, the cerebellum, and the auditory cortices, whereas the supplementary motor area (SMA) was not activated. The SMA is known to function for motor planning and programming and is usually activated in normal phonation. Several previous reports have shown that the damage of the SMA caused a severe disturbance of voluntary vocalization. In the present case, it was suggested that the functional deficit of the SMA might be related to SD.

  3. Visual cortical areas of the mouse: comparison of parcellation and network structure with primates.

    Science.gov (United States)

    Laramée, Marie-Eve; Boire, Denis

    2014-01-01

    Brains have evolved to optimize sensory processing. In primates, complex cognitive tasks must be executed and evolution led to the development of large brains with many cortical areas. Rodents do not accomplish cognitive tasks of the same level of complexity as primates and remain with small brains both in relative and absolute terms. But is a small brain necessarily a simple brain? In this review, several aspects of the visual cortical networks have been compared between rodents and primates. The visual system has been used as a model to evaluate the level of complexity of the cortical circuits at the anatomical and functional levels. The evolutionary constraints are first presented in order to appreciate the rules for the development of the brain and its underlying circuits. The organization of sensory pathways, with their parallel and cross-modal circuits, is also examined. Other features of brain networks, often considered as imposing constraints on the development of underlying circuitry, are also discussed and their effect on the complexity of the mouse and primate brain are inspected. In this review, we discuss the common features of cortical circuits in mice and primates and see how these can be useful in understanding visual processing in these animals.

  4. Differential tinnitus-related neuroplastic alterations of cortical thickness and surface area.

    Science.gov (United States)

    Meyer, Martin; Neff, Patrick; Liem, Franziskus; Kleinjung, Tobias; Weidt, Steffi; Langguth, Berthold; Schecklmann, Martin

    2016-12-01

    Structural neuroimaging techniques have been used to identify cortical and subcortical regions constituting the neuroarchitecture of tinnitus. One recent investigation used voxel-based morphometry (VBM) to analyze a sample of tinnitus patients (TI, n = 257) (Schecklmann et al., 2013). A negative relationship between individual distress and cortical volume (CV) in bilateral auditory regions was observed. However, CV has meanwhile been identified as a neuroanatomical measurement that confounds genetically distinct neuroanatomical traits, namely cortical thickness (CT) and cortical surface area (CSA). We performed a re-analysis of the identical sample using the automated FreeSurfer surface-based morphometry (SBM) approach (Fischl, 2012). First, we replicated the negative correlation between tinnitus distress and bilateral supratemporal gray matter volume. Second, we observed a negative correlation for CSA in the left periauditory cortex and anterior insula. Furthermore, we noted a positive correlation between tinnitus duration and CT in the left periauditory cortex as well as a negative correlation in the subcallosal anterior cingulate, a region collated to the serotonergic circuit and germane to inhibitory functions. In short, the results elucidate differential neuroanatomical alterations of CSA and CT for the two independent tinnitus-related psychological traits distress and duration. Beyond this, the study provides further evidence for the distinction and specific susceptibility of CSA and CT within the context of neuroplasticity of the human brain. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Two-dimensional map of direction selectivity in cortical visual area MT of Cebus monkey

    OpenAIRE

    ANTONIA CINIRA M. DIOGO; Soares, Juliana G. M.; Albright, Thomas D.; RICARDO GATTASS

    2002-01-01

    We studied the spatial organization of direction of motion in visual area MT of the Cebus apella monkey. We used arrays of 6 (700 µm apart) parallel electrodes in penetrations tangential to the cortical layers to record multi-unit responses to moving bars, at 200 µm steps. We determined the direction selectivity at each recording site. The data from single penetrations showed cyclic and gradual changes in the direction selectivity of clusters of cells, intermixed with abrupt 180º discontinuit...

  6. Auditory cortical areas activated by slow frequency-modulated sounds in mice.

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    Yuusuke Honma

    Full Text Available Species-specific vocalizations in mice have frequency-modulated (FM components slower than the lower limit of FM direction selectivity in the core region of the mouse auditory cortex. To identify cortical areas selective to slow frequency modulation, we investigated tonal responses in the mouse auditory cortex using transcranial flavoprotein fluorescence imaging. For differentiating responses to frequency modulation from those to stimuli at constant frequencies, we focused on transient fluorescence changes after direction reversal of temporally repeated and superimposed FM sweeps. We found that the ultrasonic field (UF in the belt cortical region selectively responded to the direction reversal. The dorsoposterior field (DP also responded weakly to the reversal. Regarding the responses in UF, no apparent tonotopic map was found, and the right UF responses were significantly larger in amplitude than the left UF responses. The half-max latency in responses to FM sweeps was shorter in UF compared with that in the primary auditory cortex (A1 or anterior auditory field (AAF. Tracer injection experiments in the functionally identified UF and DP confirmed that these two areas receive afferent inputs from the dorsal part of the medial geniculate nucleus (MG. Calcium imaging of UF neurons stained with fura-2 were performed using a two-photon microscope, and the presence of UF neurons that were selective to both direction and direction reversal of slow frequency modulation was demonstrated. These results strongly suggest a role for UF, and possibly DP, as cortical areas specialized for processing slow frequency modulation in mice.

  7. Procedure for recording the simultaneous activity of single neurons distributed across cortical areas during sensory discrimination

    Science.gov (United States)

    Hernández, Adrián; Nácher, Verónica; Luna, Rogelio; Alvarez, Manuel; Zainos, Antonio; Cordero, Silvia; Camarillo, Liliana; Vázquez, Yuriria; Lemus, Luis; Romo, Ranulfo

    2008-01-01

    We report a procedure for recording the simultaneous activity of single neurons distributed across five cortical areas in behaving monkeys. The procedure consists of a commercially available microdrive adapted to a commercially available neural data collection system. The critical advantage of this procedure is that, in each cortical area, a configuration of seven microelectrodes spaced 250–500 μm can be inserted transdurally and each can be moved independently in the z axis. For each microelectrode, the data collection system can record the activity of up to five neurons together with the local field potential (LFP). With this procedure, we normally monitor the simultaneous activity of 70–100 neurons while trained monkeys discriminate the difference in frequency between two vibrotactile stimuli. Approximately 20–60 of these neurons have response properties previously reported in this task. The neuronal recordings show good signal-to-noise ratio, are remarkably stable along a 1-day session, and allow testing several protocols. Microelectrodes are removed from the brain after a 1-day recording session, but are reinserted again the next day by using the same or different x-y microelectrode array configurations. The fact that microelectrodes can be moved in the z axis during the recording session and that the x-y configuration can be changed from day to day maximizes the probability of studying simultaneous interactions, both local and across distant cortical areas, between neurons associated with the different components of this task. PMID:18946031

  8. Combining MRI and VEP imaging to isolate the temporal response of visual cortical areas

    Science.gov (United States)

    Carney, Thom; Ales, Justin; Klein, Stanley A.

    2008-02-01

    The human brain has well over 30 cortical areas devoted to visual processing. Classical neuro-anatomical as well as fMRI studies have demonstrated that early visual areas have a retinotopic organization whereby adjacent locations in visual space are represented in adjacent areas of cortex within a visual area. At the 2006 Electronic Imaging meeting we presented a method using sprite graphics to obtain high resolution retinotopic visual evoked potential responses using multi-focal m-sequence technology (mfVEP). We have used this method to record mfVEPs from up to 192 non overlapping checkerboard stimulus patches scaled such that each patch activates about 12 mm2 of cortex in area V1 and even less in V2. This dense coverage enables us to incorporate cortical folding constraints, given by anatomical MRI and fMRI results from the same subject, to isolate the V1 and V2 temporal responses. Moreover, the method offers a simple means of validating the accuracy of the extracted V1 and V2 time functions by comparing the results between left and right hemispheres that have unique folding patterns and are processed independently. Previous VEP studies have been contradictory as to which area responds first to visual stimuli. This new method accurately separates the signals from the two areas and demonstrates that both respond with essentially the same latency. A new method is introduced which describes better ways to isolate cortical areas using an empirically determined forward model. The method includes a novel steady state mfVEP and complex SVD techniques. In addition, this evolving technology is put to use examining how stimulus attributes differentially impact the response in different cortical areas, in particular how fast nonlinear contrast processing occurs. This question is examined using both state triggered kernel estimation (STKE) and m-sequence "conditioned kernels". The analysis indicates different contrast gain control processes in areas V1 and V2. Finally we

  9. 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.

  10. A cortical-subcortical syntax pathway linking Broca's area and the striatum.

    Science.gov (United States)

    Teichmann, Marc; Rosso, Charlotte; Martini, Jean-Baptiste; Bloch, Isabelle; Brugières, Pierre; Duffau, Hugues; Lehéricy, Stéphane; Bachoud-Lévi, Anne-Catherine

    2015-06-01

    Combinatorial syntax has been shown to be underpinned by cortical key regions such as Broca's area and temporal cortices, and by subcortical structures such as the striatum. The cortical regions are connected via several cortico-to-cortical tracts impacting syntactic processing (e.g., the arcuate) but it remains unclear whether and how the striatum can be integrated into this cortex-centered syntax network. Here, we used a systematic stepwise approach to investigate the existence and syntactic function of an additional deep Broca-striatum pathway. We first asked 15 healthy controls and 12 patients with frontal/striatal lesions to perform three syntax tests. The results obtained were subjected to voxel-based lesion-symptom mapping (VLSM) to provide an anatomo-functional approximation of the pathway. The significant VLSM clusters were then overlapped with the probability maps of four cortico-cortical language tracts generated for 12 healthy participants (arcuate, extreme capsule fiber system, uncinate, aslant), including a probabilistic Broca-striatum tract. Finally, we carried out quantitative analyses of the relationship between the lesion load along the tracts and syntactic processing, by calculating tract-lesion overlap for each patient and analyzing the correlation with syntactic data. Our findings revealed a Broca-striatum tract linking BA45 with the left caudate head and overlapping with VLSM voxel clusters relating to complex syntax. The lesion load values for this tract were correlated with complex syntax scores, whereas no such correlation was observed for the other tracts. These results extend current syntax-network models, by adding a deep "Broca-caudate pathway," and are consistent with functional accounts of frontostriatal circuits.

  11. Mapping cortical areas associated with Chinese word processing using functiona l magnetic resonance imaging

    Institute of Scientific and Technical Information of China (English)

    马林; 唐一源; 王岩; 李德军; 翁旭初; 张武田; 庄建程; 胡小平

    2003-01-01

    Objectives To identify the cortical areas engaged during Chinese word processing using func tional magnetic resonance imaging (fMRI) and to examine the reliability and repr oducibility of fMRI for localization of functional areas in the human brain.Methods FMRI data were collected on 8 young, right-handed, native Chinese speakers duri ng performance of Chinese synonym and homophone judgment tasks on two different clinical MRI systems (1.5 T GE Signa Horizon and 1.5 T Siemens Vision). A cro ss correlation analysis was used to statistically generate the activation map.Results Broca's area, Wernicke's area, bilateral extrastriate, and ventral tempo ral cortex were significantly activated during both the synonym and homophone activities. There was essentially no difference between results acquired on two different MRI systems.Conclusions FMRI can be used for localizing cortical areas critical to Chinese language proc essing in the human brain. The results are reliable and well reproducible acros s different clinical MRI systems.

  12. The cortical activation pattern during bilateral arm raising movements

    Science.gov (United States)

    Jang, Sung Ho; Seo, Jung Pyo; Lee, Seung-Hyun; Jin, Sang-Hyun; Yeo, Sang Seok

    2017-01-01

    Bilateral arm raising movements have been used in brain rehabilitation for a long time. However, no study has been reported on the effect of these movements on the cerebral cortex. In this study, using functional near infrared spectroscopy (fNIRS), we attempted to investigate cortical activation generated during bilateral arm raising movements. Ten normal subjects were recruited for this study. fNIRS was performed using an fNIRS system with 49 channels. Bilateral arm raising movements were performed in sitting position at the rate of 0.5 Hz. We measured values of oxyhemoglobin and total hemoglobin in five regions of interest: the primary sensorimotor cortex, premotor cortex, supplementary motor area, prefrontal cortex, and posterior parietal cortex. During performance of bilateral arm raising movements, oxyhemoglobin and total hemoglobin values in the primary sensorimotor cortex, premotor cortex, supplementary motor area, and prefrontal cortex were similar, but higher in these regions than those in the prefrontal cortex. We observed activation of the arm somatotopic areas of the primary sensorimotor cortex and premotor cortex in both hemispheres during bilateral arm raising movements. According to this result, bilateral arm raising movements appeared to induce large-scale neuronal activation and therefore arm raising movements would be good exercise for recovery of brain functions. PMID:28400816

  13. Calretinin as a marker for premotor neurons involved in upgaze in human brainstem

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    Christopher eAdamczyk

    2015-12-01

    Full Text Available Eye movements are generated by different premotor pathways. Damage to them can cause specific deficits of eye movements, such as saccades. For correlative clinico-anatomical post-mortem studies of cases with eye movement disorders it is essential to identify the functional cell groups of the oculomotor system in the human brain by marker proteins. Based on monkey studies, the premotor neurons of the saccadic system can be identified by the histochemical markers parvalbumin and perineuronal nets in humans. These areas involve the interstitial nucleus of Cajal (INC and the rostral interstitial nucleus of the medial longitudinal fascicle (RIMLF, which both contain premotor neurons for upgaze and downgaze. Recent monkey and human studies revealed a selective excitatory calretinin-positive input to the motoneurons mediating upgaze, but not to those for downgaze. Three premotor regions were identified as sources of calretinin input in monkey: y-group, INC and RIMLF. These findings suggest that the expression pattern of parvalbumin and calretinin may help to identify premotor neurons involved in up- or downgaze. In a post-mortem study of five human cases without neurological diseases we investigated the y-group, INC and RIMLF for the presence of parvalbumin and calretinin positive neurons including their co-expression. Adjacent thin paraffin sections were stained for the aggrecan component of perineuronal nets, parvalbumin or calretinin and glutamate decarboxylase. The comparative analysis of scanned thin sections of INC and RIMLF revealed medium-sized parvalbumin positive neurons with and without calretinin coexpression, which were intermingled. The parvalbumin/calretinin positive neurons in both nuclei are considered as excitatory premotor upgaze neurons. Accordingly, the parvalbumin-positive neurons lacking calretinin are considered as premotor downgaze neurons in RIMLF, but may in addition include inhibitory premotor upgaze neurons in the INC as

  14. Preoperative 3T high field blood oxygen level dependent functional magnetic resonance imaging for glioma involving sensory cortical areas

    Institute of Scientific and Technical Information of China (English)

    LI Shao-wu; WANG Jiang-fei; JIANG Tao; LI Shou-wei; ZHANG Wen-bo; LI Zi-xiao; ZHANG Zhong; DAI Jian-ping; WANG Zhong-cheng

    2010-01-01

    Background Localization of sensory cortical areas during the operation is essential to preserve the sensory function.Intraoperative direct electrostimulation under awake anesthesia is the golden standard but time-consuming. We applied 3T high field blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) to identify the relationship between glioma and cortical sensory areas preoperatively and to guide intraoperative direct electrostimulation for quick and precise localization.Methods Five glioma patients with sensory cortex involvement by or next to the lesion had preoperative BOLD fMRI to determine the spatial relationship of cortical sensory areas to the tumours. Bilateral hand opposite movement was performed by these patients for fMRI. Precentral and postcentral gyri were identified by electrical stimulation during the operation. Karnofsky Performance Status scores of the patients' pre- and postoperative and the role of BOLD fMRI were evaluated.Results The cortical sensory areas were all activated in five glioma patients involving postcentral gyrus areas by BOLDf MRI with bilateral hand opposite movement. The detected activation areas corresponded with the results from cortical electrical stimulation.Conclusions The relationship between cortical sensory areas and tumour can be accurately shown by BOLD fMRI before operation. And the information used to make the tumour resection could obtain good clinical results.

  15. Cortico–Cortical Connections of Primary Sensory Areas and Associated Symptoms in Migraine

    Science.gov (United States)

    Veggeberg, Rosanna; Wilcox, Sophie L.; Scrivani, Steven J.; Borsook, David

    2016-01-01

    Abstract Migraine is a recurring, episodic neurological disorder characterized by headache, nausea, vomiting, and sensory disturbances. These events are thought to arise from the activation and sensitization of neurons along the trigemino–vascular pathway. From animal studies, it is known that thalamocortical projections play an important role in the transmission of nociceptive signals from the meninges to the cortex. However, little is currently known about the potential involvement of cortico–cortical feedback projections from higher-order multisensory areas and/or feedforward projections from principle primary sensory areas or subcortical structures. In a large cohort of human migraine patients (N = 40) and matched healthy control subjects (N = 40), we used resting-state intrinsic functional connectivity to examine the cortical networks associated with the three main sensory perceptual modalities of vision, audition, and somatosensation. Specifically, we sought to explore the complexity of the sensory networks as they converge and become functionally coupled in multimodal systems. We also compared self-reported retrospective migraine symptoms in the same patients, examining the prevalence of sensory symptoms across the different phases of the migraine cycle. Our results show widespread and persistent disturbances in the perceptions of multiple sensory modalities. Consistent with this observation, we discovered that primary sensory areas maintain local functional connectivity but express impaired long-range connections to higher-order association areas (including regions of the default mode and salience network). We speculate that cortico–cortical interactions are necessary for the integration of information within and across the sensory modalities and, thus, could play an important role in the initiation of migraine and/or the development of its associated symptoms. PMID:28101529

  16. Cortical Thickness in Fusiform Face Area Predicts Face and Object Recognition Performance.

    Science.gov (United States)

    McGugin, Rankin W; Van Gulick, Ana E; Gauthier, Isabel

    2016-02-01

    The fusiform face area (FFA) is defined by its selectivity for faces. Several studies have shown that the response of FFA to nonface objects can predict behavioral performance for these objects. However, one possible account is that experts pay more attention to objects in their domain of expertise, driving signals up. Here, we show an effect of expertise with nonface objects in FFA that cannot be explained by differential attention to objects of expertise. We explore the relationship between cortical thickness of FFA and face and object recognition using the Cambridge Face Memory Test and Vanderbilt Expertise Test, respectively. We measured cortical thickness in functionally defined regions in a group of men who evidenced functional expertise effects for cars in FFA. Performance with faces and objects together accounted for approximately 40% of the variance in cortical thickness of several FFA patches. Whereas participants with a thicker FFA cortex performed better with vehicles, those with a thinner FFA cortex performed better with faces and living objects. The results point to a domain-general role of FFA in object perception and reveal an interesting double dissociation that does not contrast faces and objects but rather living and nonliving objects.

  17. Dynamics of Electrocorticographic (ECoG) Activity in Human Temporal and Frontal Cortical Areas During Music Listening

    Science.gov (United States)

    2012-04-14

    REPORT Dynamics of electrocorticographic (ECoG) activity in human temporal and frontal cortical areas during music listening 14. ABSTRACT 16. SECURITY...information about the sound intensity of music . ECoG activity in the high gamma band recorded from the posterior part of the superior temporal 1. REPORT...ECoG) activity in human temporal and frontal cortical areas during music listening Report Title ABSTRACT Previous studies demonstrated that brain

  18. Multisensory and Modality Specific Processing of Visual Speech in Different Regions of the Premotor Cortex

    Directory of Open Access Journals (Sweden)

    Daniel eCallan

    2014-05-01

    Full Text Available Behavioral and neuroimaging studies have demonstrated that brain regions involved with speech production also support speech perception, especially under degraded conditions. The premotor cortex has been shown to be active during both observation and execution of action (‘Mirror System’ properties, and may facilitate speech perception by mapping unimodal and multimodal sensory features onto articulatory speech gestures. For this functional magnetic resonance imaging (fMRI study, participants identified vowels produced by a speaker in audio-visual (saw the speaker’s articulating face and heard her voice, visual only (only saw the speaker’s articulating face, and audio only (only heard the speaker’s voice conditions with varying audio signal-to-noise ratios in order to determine the regions of the premotor cortex involved with multisensory and modality specific processing of visual speech gestures. The task was designed so that identification could be made with a high level of accuracy from visual only stimuli to control for task difficulty and differences in intelligibility. The results of the fMRI analysis for visual only and audio-visual conditions showed overlapping activity in inferior frontal gyrus and premotor cortex. The left ventral inferior premotor cortex showed properties of multimodal (audio-visual enhancement with a degraded auditory signal. The left inferior parietal lobule and right cerebellum also showed these properties. The left ventral superior and dorsal premotor cortex did not show this multisensory enhancement effect, but there was greater activity for the visual only over audio-visual conditions in these areas. The results suggest that the inferior regions of the ventral premotor cortex are involved with integrating multisensory information, whereas, more superior and dorsal regions of the premotor cortex are involved with mapping unimodal (in this case visual sensory features of the speech signal with

  19. Activity in ventral premotor cortex is modulated by vision of own hand in action

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    Luciano Fadiga

    2013-07-01

    Full Text Available Parietal and premotor cortices of the macaque monkey contain distinct populations of neurons which, in addition to their motor discharge, are also activated by visual stimulation. Among these visuomotor neurons, a population of grasping neurons located in the anterior intraparietal area (AIP shows discharge modulation when the own hand is visible during object grasping. Given the dense connections between AIP and inferior frontal regions, we aimed at investigating whether two hand-related frontal areas, ventral premotor area F5 and primary motor cortex (area F1, contain neurons with similar properties. Two macaques were involved in a grasping task executed in various light/dark conditions in which the to-be-grasped object was kept visible by a dim retro-illumination. Approximately 62% of F5 and 55% of F1 motor neurons showed light/dark modulations. To better isolate the effect of hand-related visual input, we introduced two further conditions characterized by kinematic features similar to the dark condition. The scene was briefly illuminated (i during hand preshaping (pre-touch flash, PT-flash and (ii at hand-object contact (touch flash, T-flash. Approximately 48% of F5 and 44% of F1 motor neurons showed a flash-related modulation. Considering flash-modulated neurons in the two flash conditions, ∼40% from F5 and ∼52% from F1 showed stronger activity in PT- than T-flash (PT-flash-dominant, whereas ∼60% from F5 and ∼48% from F1 showed stronger activity in T- than PT-flash (T-flash-dominant. Furthermore, F5, but not F1, flash-dominant neurons were characterized by a higher peak and mean discharge in the preferred flash condition as compared to light and dark conditions. Still considering F5, the distribution of the time of peak discharge was similar in light and preferred flash conditions. This study shows that the frontal cortex contains neurons, previously classified as motor neurons, which are sensitive to the observation of meaningful

  20. Cortical thickness, surface area and volume measures in Parkinson's disease, multiple system atrophy and progressive supranuclear palsy.

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    Amanda Worker

    Full Text Available Parkinson's disease (PD, Multiple System Atrophy (MSA and Progressive Supranuclear Palsy (PSP are neurodegenerative diseases that can be difficult to distinguish clinically. The objective of the current study was to use surface-based analysis techniques to assess cortical thickness, surface area and grey matter volume to identify unique morphological patterns of cortical atrophy in PD, MSA and PSP and to relate these patterns of change to disease duration and clinical features.High resolution 3D T1-weighted MRI volumes were acquired from 14 PD patients, 18 MSA, 14 PSP and 19 healthy control participants. Cortical thickness, surface area and volume analyses were carried out using the automated surface-based analysis package FreeSurfer (version 5.1.0. Measures of disease severity and duration were assessed for correlation with cortical morphometric changes in each clinical group.Results show that in PSP, widespread cortical thinning and volume loss occurs within the frontal lobe, particularly the superior frontal gyrus. In addition, PSP patients also displayed increased surface area in the pericalcarine. In comparison, PD and MSA did not display significant changes in cortical morphology.These results demonstrate that patients with clinically established PSP exhibit distinct patterns of cortical atrophy, particularly affecting the frontal lobe. These results could be used in the future to develop a useful clinical application of MRI to distinguish PSP patients from PD and MSA patients.

  1. Cortical areas related to performance of WAIS Digit Symbol Test: a functional imaging study.

    Science.gov (United States)

    Usui, Nobuo; Haji, Tomoki; Maruyama, Masakazu; Katsuyama, Narumi; Uchida, Shinya; Hozawa, Atsushi; Omori, Kahoru; Tsuji, Ichiro; Kawashima, Ryuta; Taira, Masato

    2009-09-29

    Many neuropsychological studies have shown that the Digit Symbol Test (DST) of the Wechsler Adult Intelligence Scale (WAIS) is useful for screening for dysfunctions of the brain. However, it remains unclear which brain areas are actually involved in the performance of DST and what brain functions are used for executing this test. In this study, we examined the cortical areas related to cognitive aspects of DST using functional magnetic resonance imaging (fMRI) and determined executive brain functions involved in this test on the basis of fMRI results. Eleven healthy young adults (mean=21.6 years) performed a modified DST (mDST) task and its control task, which required a simple graphomotor response during fMRI data acquisition. The direct comparison of brain activations between the mDST task and the control task revealed greater activations in a fronto-parietal cortical network, including the bilateral inferior frontal sulci, left middle frontal gyrus (close to the frontal eye field) and left posterior parietal cortex. These activations are interpreted as reflecting the visual search process and/or the updating process of working memory during the mDST task execution. Furthermore, we found a positive correlation between the number of correct responses and activations in the bilateral inferior frontal regions, suggesting that these prefrontal areas have a crucial role in the performance of DST in a healthy young adult population.

  2. Direct projections from the dorsal premotor cortex to the superior colliculus in the macaque (macaca mulatta).

    Science.gov (United States)

    Distler, Claudia; Hoffmann, Klaus-Peter

    2015-11-01

    The dorsal premotor cortex (PMd) is part of the cortical network for arm movements during reach-related behavior. Here we investigate the neuronal projections from the PMd to the midbrain superior colliculus (SC), which also contains reach-related neurons, to investigate how the SC integrates into a cortico-subcortical network responsible for initiation and modulation of goal-directed arm movements. By using anterograde transport of neuronal tracers, we found that the PMd projects most strongly to the deep layers of the lateral part of the SC and the underlying reticular formation corresponding to locations where reach-related neurons have been recorded, and from where descending tectofugal projections arise. A somewhat weaker projection targets the intermediate layers of the SC. By contrast, terminals originating from prearcuate area 8 mainly project to the intermediate layers of the SC. Thus, this projection pattern strengthens the view that different compartments in the SC are involved in the control of gaze and in the control or modulation of reaching movements. The PMD-SC projection assists in the participation of the SC in the skeletomotor system and provides the PMd with a parallel path to elicit forelimb movements.

  3. State-dependent changes in auditory sensory gating in different cortical areas in rats.

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    Renli Qi

    Full Text Available Sensory gating is a process in which the brain's response to a repetitive stimulus is attenuated; it is thought to contribute to information processing by enabling organisms to filter extraneous sensory inputs from the environment. To date, sensory gating has typically been used to determine whether brain function is impaired, such as in individuals with schizophrenia or addiction. In healthy subjects, sensory gating is sensitive to a subject's behavioral state, such as acute stress and attention. The cortical response to sensory stimulation significantly decreases during sleep; however, information processing continues throughout sleep, and an auditory evoked potential (AEP can be elicited by sound. It is not known whether sensory gating changes during sleep. Sleep is a non-uniform process in the whole brain with regional differences in neural activities. Thus, another question arises concerning whether sensory gating changes are uniform in different brain areas from waking to sleep. To address these questions, we used the sound stimuli of a Conditioning-testing paradigm to examine sensory gating during waking, rapid eye movement (REM sleep and Non-REM (NREM sleep in different cortical areas in rats. We demonstrated the following: 1. Auditory sensory gating was affected by vigilant states in the frontal and parietal areas but not in the occipital areas. 2. Auditory sensory gating decreased in NREM sleep but not REM sleep from waking in the frontal and parietal areas. 3. The decreased sensory gating in the frontal and parietal areas during NREM sleep was the result of a significant increase in the test sound amplitude.

  4. Reperfusion of specific cortical areas is associated with improvement in distinct forms of hemispatial neglect.

    Science.gov (United States)

    Khurshid, Shaan; Trupe, Lydia A; Newhart, Melissa; Davis, Cameron; Molitoris, John J; Medina, Jared; Leigh, Richard; Hillis, Argye E

    2012-05-01

    To test the hypothesis that restoring blood flow to specific right cortical regions in acute stroke results in improvement in distinct forms of hemispatial neglect distinguished by reference frame: viewer-centered versus stimulus-centered neglect. Twenty five patients with acute right stroke were evaluated at Day 1 and Day 3-5 with a battery of neglect tests and Diffusion- and Perfusion-Weighted MR Imaging. Multivariate linear regression analysis revealed Brodmann areas (BAs) where reperfusion predicted degree of improvement in scores on each type of neglect, independently of reperfusion of other areas, total change in the volume of infarct or hypoperfusion, and age. Reperfusion of dorsal frontoparietal cortex (including BAs 40, 46, and 4) independently predicted improvement in viewer-centered neglect, such as detecting stimuli on left in line cancellation and scene copying (r=.951; p<.0001). Reperfusion of a more ventral temporo-occipital cortex, including right BAs 37, 38, 21 and 18, independently contributed to improvement in stimulus-centered neglect, such as detecting left gaps in circles (r=.926; p<.0001). Reperfusion of right midfusiform gyrus (temporal occipital cortex), change in total volume of ischemia, change in volume of hypoperfusion and age predicted degree of improvement in reading (reduction in "neglect dyslexic" errors; r=.915; p<.0001). Results demonstrate that reperfusing specific cortical regions yields improvement in different types of neglect. Copyright © 2011 Elsevier Srl. All rights reserved.

  5. Increased facilitatory connectivity from the pre-SMA to the left dorsal premotor cortex during pseudoword repetition

    DEFF Research Database (Denmark)

    Hartwigsen, Gesa; Saur, Dorothee; Price, Cathy J

    2013-01-01

    were common to repetition in both modalities. We thus obtained three seed regions: the bilateral pre-SMA, left dorsal premotor cortex (PMd), and left ventral premotor cortex that were used to test 63 different models of effective connectivity in the premotor network for pseudoword relative to word...... repetition. The optimal model was identified with Bayesian model selection and reflected a network with driving input to pre-SMA and an increase in facilitatory drive from pre-SMA to PMd during repetition of pseudowords. The task-specific increase in effective connectivity from pre-SMA to left PMd suggests...... that the pre-SMA plays a supervisory role in the generation and subsequent sequencing of motor plans. Diffusion tensor imaging-based fiber tracking in another group of healthy volunteers showed that the functional connection between both regions is underpinned by a direct cortico-cortical anatomical connection....

  6. Wide-field retinotopy defines human cortical visual area v6.

    Science.gov (United States)

    Pitzalis, Sabrina; Galletti, Claudio; Huang, Ruey-Song; Patria, Fabiana; Committeri, Giorgia; Galati, Gaspare; Fattori, Patrizia; Sereno, Martin I

    2006-07-26

    The retinotopic organization of a newly identified visual area near the midline in the dorsalmost part of the human parieto-occipital sulcus was mapped using high-field functional magnetic resonance imaging, cortical surface-based analysis, and wide-field retinotopic stimulation. This area was found in all 34 subjects that were mapped. It represents the contralateral visual hemifield in both hemispheres of all subjects, with upper fields located anterior and medial to areas V2/V3, and lower fields medial and slightly anterior to areas V3/V3A. It contains a representation of the center of gaze distinct from V3A, a large representation of the visual periphery, and a mirror-image representation of the visual field. Based on similarity in position, visuotopic organization, and relationship with the neighboring extrastriate visual areas, we suggest it might be the human homolog of macaque area V6, and perhaps of area M (medial) or DM (dorsomedial) of New World primates.

  7. Role of fusiform and anterior temporal cortical areas in facial recognition.

    Science.gov (United States)

    Nasr, Shahin; Tootell, Roger B H

    2012-11-15

    Recent fMRI studies suggest that cortical face processing extends well beyond the fusiform face area (FFA), including unspecified portions of the anterior temporal lobe. However, the exact location of such anterior temporal region(s), and their role during active face recognition, remain unclear. Here we demonstrate that (in addition to FFA) a small bilateral site in the anterior tip of the collateral sulcus ('AT'; the anterior temporal face patch) is selectively activated during recognition of faces but not houses (a non-face object). In contrast to the psychophysical prediction that inverted and contrast reversed faces are processed like other non-face objects, both FFA and AT (but not other visual areas) were also activated during recognition of inverted and contrast reversed faces. However, response accuracy was better correlated to recognition-driven activity in AT, compared to FFA. These data support a segregated, hierarchical model of face recognition processing, extending to the anterior temporal cortex.

  8. Attention decreases phase-amplitude coupling, enhancing stimulus discriminability in cortical area MT

    Directory of Open Access Journals (Sweden)

    Moein eEsghaei

    2015-12-01

    Full Text Available Local field potentials (LFPs in cortex reflect synchronous fluctuations in the activity of local populations of neurons. The power of high frequency (>30 Hz oscillations in LFPs is locked to the phase of low frequency (<30 Hz oscillations, an effect known as phase-amplitude coupling (PAC. While PAC has been observed in a variety of cortical regions and animal models, its functional role particularly in primate visual cortex is largely unknown. Here we document PAC for LFPs recorded from extra-striate area MT of macaque monkeys, an area specialized for the processing of visual motion. We further show that directing spatial attention into the receptive field of MT neurons decreases the coupling between the low frequency phase and high frequency power of LFPs. This attentional suppression of PAC increases neuronal discriminability for attended visual stimuli. Therefore we hypothesize that visual cortex uses PAC to regulate inter-neuronal correlations and thereby enhances the coding of relevant stimuli.

  9. Brain cortical thickness and surface area correlates of neurocognitive performance in patients with schizophrenia, bipolar disorder, and healthy adults.

    Science.gov (United States)

    Hartberg, C B; Sundet, K; Rimol, L M; Haukvik, U K; Lange, E H; Nesvåg, R; Dale, A M; Melle, I; Andreassen, O A; Agartz, I

    2011-11-01

    Relationships between cortical brain structure and neurocognitive functioning have been reported in schizophrenia, but findings are inconclusive, and only a few studies in bipolar disorder have addressed this issue. This is the first study to directly compare relationships between cortical thickness and surface area with neurocognitive functioning in patients with schizophrenia (n = 117) and bipolar disorder (n = 121) and healthy controls (n = 192). MRI scans were obtained, and regional cortical thickness and surface area measurements were analyzed for relationships with test scores from 6 neurocognitive domains. In the combined sample, cortical thickness in the right rostral anterior cingulate was inversely related to working memory, and cortical surface area in four frontal and temporal regions were positively related to neurocognitive functioning. A positive relationship between left transverse temporal thickness and processing speed was specific to schizophrenia. A negative relationship between right temporal pole thickness and working memory was specific to bipolar disorder. In conclusion, significant cortical structure/function relationships were found in a large sample of healthy controls and patients with schizophrenia or bipolar disorder. The differences that were found between schizophrenia and bipolar may indicate differential relationship patterns in the two disorders, which may be of relevance for understanding the underlying pathophysiology.

  10. Pragmatics in action: indirect requests engage theory of mind areas and the cortical motor network.

    Science.gov (United States)

    van Ackeren, Markus J; Casasanto, Daniel; Bekkering, Harold; Hagoort, Peter; Rueschemeyer, Shirley-Ann

    2012-11-01

    Research from the past decade has shown that understanding the meaning of words and utterances (i.e., abstracted symbols) engages the same systems we used to perceive and interact with the physical world in a content-specific manner. For example, understanding the word "grasp" elicits activation in the cortical motor network, that is, part of the neural substrate involved in planned and executing a grasping action. In the embodied literature, cortical motor activation during language comprehension is thought to reflect motor simulation underlying conceptual knowledge [note that outside the embodied framework, other explanations for the link between action and language are offered, e.g., Mahon, B. Z., & Caramazza, A. A critical look at the embodied cognition hypothesis and a new proposal for grouding conceptual content. Journal of Physiology, 102, 59-70, 2008; Hagoort, P. On Broca, brain, and binding: A new framework. Trends in Cognitive Sciences, 9, 416-423, 2005]. Previous research has supported the view that the coupling between language and action is flexible, and reading an action-related word form is not sufficient for cortical motor activation [Van Dam, W. O., van Dijk, M., Bekkering, H., & Rueschemeyer, S.-A. Flexibility in embodied lexical-semantic representations. Human Brain Mapping, doi: 10.1002/hbm.21365, 2011]. The current study goes one step further by addressing the necessity of action-related word forms for motor activation during language comprehension. Subjects listened to indirect requests (IRs) for action during an fMRI session. IRs for action are speech acts in which access to an action concept is required, although it is not explicitly encoded in the language. For example, the utterance "It is hot here!" in a room with a window is likely to be interpreted as a request to open the window. However, the same utterance in a desert will be interpreted as a statement. The results indicate (1) that comprehension of IR sentences activates cortical

  11. The effects of caffeine ingestion on cortical areas: functional imaging study.

    Science.gov (United States)

    Park, Chan-A; Kang, Chang-Ki; Son, Young-Don; Choi, Eun-Jung; Kim, Sang-Hoon; Oh, Seung-Taek; Kim, Young-Bo; Park, Chan-Woong; Cho, Zang-Hee

    2014-05-01

    The effect of caffeine as a cognitive enhancer is well known; however, caffeine-induced changes in the cortical regions are still not very clear. Therefore, in this study, we conducted an investigation of the activation and deactivation with blood-oxygenation-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) and of metabolic activity change with positron emission tomography (PET) in the human brain. Fourteen healthy subjects performed a visuomotor task inducing attention with 3T MRI, and PET imaging was also carried out in seven subjects to determine the cerebral glucose metabolic changes of caffeine at rest. The result by fMRI showed increased BOLD activation in the left cerebellum, putamen, insula, thalamus and the right primary motor cortex, and decreased BOLD deactivation in the posterior medial and the left posterior lateral cortex. Also, the resting state PET data showed reduced metabolic activity in the putamen, caudate nucleus, insula, pallidum and posterior medial cortex. The common cortical regions between fMRI and PET, such as putamen, insula and posterior medial cortex, where significant changes occurred after caffeine ingestion, are well known to play an important role in cognitive function like attention. This result suggests that the effect of caffeine as a cognitive enhancer is derived by modulating the attentional areas.

  12. Local connections of excitatory neurons in motor-associated cortical areas of the rat

    Science.gov (United States)

    Kaneko, Takeshi

    2013-01-01

    In spite of recent progress in brain sciences, the local circuit of the cerebral neocortex, including motor areas, still remains elusive. Morphological works on excitatory cortical circuitry from thalamocortical (TC) afferents to corticospinal neurons (CSNs) in motor-associated areas are reviewed here. First, TC axons of motor thalamic nuclei have been re-examined by the single-neuron labeling method. There are middle layer (ML)-targeting and layer (L) 1-preferring TC axon types in motor-associated areas, being analogous to core and matrix types, respectively, of Jones (1998) in sensory areas. However, the arborization of core-like motor TC axons spreads widely and disregards the columnar structure that is the basis of information processing in sensory areas, suggesting that motor areas adopt a different information-processing framework such as area-wide laminar organization. Second, L5 CSNs receive local excitatory inputs not only from L2/3 pyramidal neurons but also from ML spiny neurons, the latter directly processing cerebellar information of core-like TC neurons (TCNs). In contrast, basal ganglia information is targeted to apical dendrites of L2/3 and L5 pyramidal neurons through matrix TCNs. Third, L6 corticothalamic neurons (CTNs) are most densely innervated by ML spiny neurons located just above CTNs. Since CTNs receive only weak connections from L2/3 and L5 pyramidal neurons, the TC recurrent circuit composed of TCNs, ML spiny neurons and CTNs appears relatively independent of the results of processing in L2/3 and L5. It is proposed that two circuits sharing the same TC projection and ML neurons are embedded in the neocortex: one includes L2/3 and L5 neurons, processes afferent information in a feedforward way and sends the processed information to other cortical areas and subcortical regions; and the other circuit participates in a dynamical system of the TC recurrent circuit and may serve as the basis of autonomous activity of the neocortex. PMID

  13. Cortical control of whisker movement.

    Science.gov (United States)

    Petersen, Carl C H

    2014-01-01

    Facial muscles drive whisker movements, which are important for active tactile sensory perception in mice and rats. These whisker muscles are innervated by cholinergic motor neurons located in the lateral facial nucleus. The whisker motor neurons receive synaptic inputs from premotor neurons, which are located within the brain stem, the midbrain, and the neocortex. Complex, distributed neural circuits therefore regulate whisker movement during behavior. This review focuses specifically on cortical whisker motor control. The whisker primary motor cortex (M1) strongly innervates brain stem reticular nuclei containing whisker premotor neurons, which might form a central pattern generator for rhythmic whisker protraction. In a parallel analogous pathway, the whisker primary somatosensory cortex (S1) strongly projects to the brain stem spinal trigeminal interpolaris nucleus, which contains whisker premotor neurons innervating muscles for whisker retraction. These anatomical pathways may play important functional roles, since stimulation of M1 drives exploratory rhythmic whisking, whereas stimulation of S1 drives whisker retraction.

  14. [Brodmann Areas 39 and 40: Human Parietal Association Area and Higher Cortical Function].

    Science.gov (United States)

    Sakurai, Yasuhisa

    2017-04-01

    The anatomy and function of the angular gyrus (Brodmann Area 39) and supramarginal gyrus (Brodmann Area 40) are described here. Both gyri constitute the inferior part of the parietal lobe. Association fibers from the angular gyrus project to the dorsolateral prefrontal cortex via the superior longitudinal fasciculus (SLF) II/arcuate fasciculus (AF), whereas those from the supramarginal gyrus project to the ventrolateral prefrontal cortex via SLF III/AF. Damage to the left angular gyrus causes kanji agraphia (lexical agraphia) and mild anomia, whereas damage to the left supramarginal gyrus causes kana alexia (phonological dyslexia) and kana agraphia (phonological agraphia). Damage to either gyrus causes Gerstmann's syndrome (finger agnosia, left-right disorientation, agraphia and acalculia) and verbal short-term memory impairment. "Angular alexia with agraphia" results from damage to the middle occipital gyrus posterior to the angular gyrus. Alexia and agraphia, with lesions in the angular or supramarginal gyrus, are characterized by kana transposition errors in reading words, which suggests the impairment of sequential phonological processing.

  15. Recovery from optic neuritis: an ROI-based analysis of LGN and visual cortical areas

    DEFF Research Database (Denmark)

    Korsholm, Kirsten; Madsen, Kristoffer Hougaard; Frederiksen, Jette L

    2007-01-01

    and neuronal plasticity in the cortical and subcortical visual pathways. To assess where recovery takes place along the visual pathway, visual activation was studied in the lateral geniculate nucleus (LGN), the main thalamic relay nucleus in the visual pathway and in three areas of the visual cortex......: the lateral occipital complexes (LOC), V1 and V2. We conducted a longitudinal functional magnetic resonance imaging (fMRI) study of regions of interest (ROI) of activation in LGN and visual cortex in 19 patients with acute ON at onset, 3 and 6 months from presentation. With fMRI we measured the activation......Optic neuritis (ON) is the first clinical manifestation in approximately 20% of patients with multiple sclerosis (MS). The inflammation and demyelination of the optic nerve are characterized by symptomatic visual impairment and retrobulbar pain, and associated with decreased visual acuity...

  16. Epileptiform activity in the mouse visual cortex interferes with cortical processing in connected areas

    Science.gov (United States)

    Petrucco, L.; Pracucci, E.; Brondi, M.; Ratto, G. M.; Landi, S.

    2017-01-01

    Epileptiform activity is associated with impairment of brain function even in absence of seizures, as demonstrated by failures in various testing paradigm in presence of hypersynchronous interictal spikes (ISs). Clinical evidence suggests that cognitive deficits might be directly caused by the anomalous activity rather than by its underlying etiology. Indeed, we seek to understand whether ISs interfere with neuronal processing in connected areas not directly participating in the hypersynchronous activity in an acute model of epilepsy. Here we cause focal ISs in the visual cortex of anesthetized mice and we determine that, even if ISs do not invade the opposite hemisphere, the local field potential is subtly disrupted with a modulation of firing probability imposed by the contralateral IS activity. Finally, we find that visual processing is altered depending on the temporal relationship between ISs and stimulus presentation. We conclude that focal ISs interact with normal cortical dynamics far from the epileptic focus, disrupting endogenous oscillatory rhythms and affecting information processing. PMID:28071688

  17. Cortical and subcortical mapping of language areas: correlation of functional MRI and tractography in a 3T scanner with intraoperative cortical and subcortical stimulation in patients with brain tumors located in eloquent areas.

    Science.gov (United States)

    Jiménez de la Peña, M; Gil Robles, S; Recio Rodríguez, M; Ruiz Ocaña, C; Martínez de Vega, V

    2013-01-01

    To describe the detection of cortical areas and subcortical pathways involved in language observed in MRI activation studies and tractography in a 3T MRI scanner and to correlate the findings of these functional studies with direct intraoperative cortical and subcortical stimulation. We present a series of 14 patients with focal brain tumors adjacent to eloquent brain areas. All patients underwent neuropsychological evaluation before and after surgery. All patients underwent MRI examination including structural sequences, perfusion imaging, spectroscopy, functional imaging to determine activation of motor and language areas, and 3D tractography. All patients underwent cortical mapping through cortical and subcortical stimulation during the operation to resect the tumor. Postoperative follow-up studies were done 24 hours after surgery. The correlation of motor function and of the corticospinal tract determined by functional MRI and tractography with intraoperative mapping of cortical and subcortical motor areas was complete. The eloquent brain areas of language expression and reception were strongly correlated with intraoperative cortical mapping in all but two cases (a high grade infiltrating glioma and a low grade glioma located in the frontal lobe). 3D tractography identified the arcuate fasciculus, the lateral part of the superior longitudinal fasciculus, the subcallosal fasciculus, the inferior fronto-occipital fasciculus, and the optic radiations, which made it possible to mark the limits of the resection. The correlation with the subcortical mapping of the anatomic arrangement of the fasciculi with respect to the lesions was complete. The best treatment for brain tumors is maximum resection without associated deficits, so high quality functional studies are necessary for preoperative planning. Copyright © 2011 SERAM. Published by Elsevier Espana. All rights reserved.

  18. Early musical training is linked to gray matter structure in the ventral premotor cortex and auditory-motor rhythm synchronization performance.

    Science.gov (United States)

    Bailey, Jennifer Anne; Zatorre, Robert J; Penhune, Virginia B

    2014-04-01

    Evidence in animals and humans indicates that there are sensitive periods during development, times when experience or stimulation has a greater influence on behavior and brain structure. Sensitive periods are the result of an interaction between maturational processes and experience-dependent plasticity mechanisms. Previous work from our laboratory has shown that adult musicians who begin training before the age of 7 show enhancements in behavior and white matter structure compared with those who begin later. Plastic changes in white matter and gray matter are hypothesized to co-occur; therefore, the current study investigated possible differences in gray matter structure between early-trained (ET; 7) musicians, matched for years of experience. Gray matter structure was assessed using voxel-wise analysis techniques (optimized voxel-based morphometry, traditional voxel-based morphometry, and deformation-based morphometry) and surface-based measures (cortical thickness, surface area and mean curvature). Deformation-based morphometry analyses identified group differences between ET and LT musicians in right ventral premotor cortex (vPMC), which correlated with performance on an auditory motor synchronization task and with age of onset of musical training. In addition, cortical surface area in vPMC was greater for ET musicians. These results are consistent with evidence that premotor cortex shows greatest maturational change between the ages of 6-9 years and that this region is important for integrating auditory and motor information. We propose that the auditory and motor interactions required by musical practice drive plasticity in vPMC and that this plasticity is greatest when maturation is near its peak.

  19. Premotor biomarkers for Parkinson's disease - a promising direction of research

    Directory of Open Access Journals (Sweden)

    Haas Brian R

    2012-05-01

    Full Text Available Abstract The second most serious neurodegenerative disease is Parkinson’s disease (PD. Over the past several decades, a strong body of evidence suggests that PD can begin years before the hallmark clinical motor symptoms appear. Biomarkers for PD are urgently needed to differentiate between neurodegenerative disorders, screen novel therapeutics, and predict eventual clinical PD before the onset of symptoms. Some clinical evaluations and neuroimaging techniques have been developed in the last several years with some success in this area. Moreover, other strategies have been utilized to identify biochemical and genetic markers associated with PD leading to the examination of PD progression and pathogenesis in cerebrospinal fluid, blood, or saliva. Finally, interesting results are surfacing from preliminary studies using known PD-associated genetic mutations to assess potential premotor PD biomarkers. The current review highlights recent advances and underscores areas of potential advancement.

  20. Can we image premotor Parkinson disease?

    Science.gov (United States)

    Marek, Kenneth; Jennings, Danna

    2009-02-17

    Pathology and imaging studies have shown that patients with Parkinson disease (PD) have a prolonged period of uncertain duration when vulnerable neuronal populations are degenerating, but typical motor symptoms have not yet developed. This provides both an opportunity-it may be best to test new medications and, ultimately, treat PD patients during this early phase of disease--and a challenge--how to find these premotor PD subjects? Imaging biomarkers targeting the premotor period are critical to elucidate both the onset and progression of premotor PD. Widespread data have demonstrated that dopaminergic imaging can detect PD subjects at the motor symptom threshold. Novel strategies combining dopaminergic imaging with known genetic mutations for PD or early clinical signs and PD-associated symptoms, such as olfactory loss and sleep disturbances like REM behavior disorder, have begun to be used to identify individuals at risk for PD before motor symptoms become manifest. Early studies also have used imaging targeting norepinephrine, serotonin, cholinergic, or other neuronal systems to focus on early cardiac, cognitive, and behavioral symptoms. Imaging of nondopaminergic targets such as inflammation or alpha-synuclein deposition may provide further insight into the etiology of PD. Given the multiple genetic etiologies for PD already identified, the marked variability in the loss of dopaminergic markers measured by imaging at motor symptom onset, and the clear heterogeneity of clinical symptoms at PD onset, it is certain that many imaging biomarkers with a focus ranging from clinical symptoms to PD pathobiology to molecular genetic mechanisms, will be necessary to fully map PD risk.

  1. Rhythmic and melodic deviations in musical sequences recruit different cortical areas for mismatch detection.

    Science.gov (United States)

    Lappe, Claudia; Steinsträter, Olaf; Pantev, Christo

    2013-01-01

    The mismatch negativity (MMN), an event-related potential (ERP) representing the violation of an acoustic regularity, is considered as a pre-attentive change detection mechanism at the sensory level on the one hand and as a prediction error signal on the other hand, suggesting that bottom-up as well as top-down processes are involved in its generation. Rhythmic and melodic deviations within a musical sequence elicit a MMN in musically trained subjects, indicating that acquired musical expertise leads to better discrimination accuracy of musical material and better predictions about upcoming musical events. Expectation violations to musical material could therefore recruit neural generators that reflect top-down processes that are based on musical knowledge. We describe the neural generators of the musical MMN for rhythmic and melodic material after a short-term sensorimotor-auditory (SA) training. We compare the localization of musical MMN data from two previous MEG studies by applying beamformer analysis. One study focused on the melodic harmonic progression whereas the other study focused on rhythmic progression. The MMN to melodic deviations revealed significant right hemispheric neural activation in the superior temporal gyrus (STG), inferior frontal cortex (IFC), and the superior frontal (SFG) and orbitofrontal (OFG) gyri. IFC and SFG activation was also observed in the left hemisphere. In contrast, beamformer analysis of the data from the rhythm study revealed bilateral activation within the vicinity of auditory cortices and in the inferior parietal lobule (IPL), an area that has recently been implied in temporal processing. We conclude that different cortical networks are activated in the analysis of the temporal and the melodic content of musical material, and discuss these networks in the context of the dual-pathway model of auditory processing.

  2. Rhythmic and melodic deviations in musical sequences recruit different cortical areas for mismatch detection

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    Claudia eLappe

    2013-06-01

    Full Text Available The mismatch negativity (MMN, an event-related potential (ERP representing the violation of an acoustic regularity, is considered as a pre-attentive change detection mechanism at the sensory level on the one hand and as a prediction error signal on the other hand, suggesting that bottom-up as well as top-down processes are involved in its generation. Rhythmic and melodic deviations within a musical sequence elicit a mismatch negativity in musically trained subjects, indicating that acquired musical expertise leads to better discrimination accuracy of musical material and better predictions about upcoming musical events. Expectation violations to musical material could therefore recruit neural generators that reflect top-down processes that are based on musical knowledge.We describe the neural generators of the musical MMN for rhythmic and melodic material after a short-term sensorimotor-auditory training. We compare the localization of musical MMN data from two previous MEG studies by applying beamformer analysis. One study focused on the melodic harmonic progression whereas the other study focused on rhythmic progression. The MMN to melodic deviations revealed significant right hemispheric neural activation in the superior temporal gyrus (STG, inferior frontal cortex (IFC, and the superior frontal (SFG and orbitofrontal (OFG gyri. IFC and SFG activation was also observed in the left hemisphere. In contrast, beamformer analysis of the data from the rhythm study revealed bilatral activation within the vicinity of auditory cortices and in the inferior parietal lobule, an area that has recently been implied in temporal processing. We conclude that different cortical networks are activated in the analysis of the temporal and the melodic content of musical material, and discuss these networks in the context of the the dual-pathway model of auditory processing.

  3. Reorganization and Stability for Motor and Language Areas Using Cortical Stimulation: Case Example and Review of the Literature

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    Serafini, Sandra; Komisarow, Jordan M.; Gallentine, William; Mikati, Mohamad A.; Bonner, Melanie J.; Kranz, Peter G.; Haglund, Michael M.; Grant, Gerald

    2013-01-01

    The cerebral organization of language in epilepsy patients has been studied with invasive procedures such as Wada testing and electrical cortical stimulation mapping and more recently with noninvasive neuroimaging techniques, such as functional MRI. In the setting of a chronic seizure disorder, clinical variables have been shown to contribute to cerebral language reorganization underscoring the need for language lateralization and localization procedures. We present a 14-year-old pediatric patient with a refractory epilepsy disorder who underwent two neurosurgical resections of a left frontal epileptic focus separated by a year. He was mapped extraoperatively through a subdural grid using cortical stimulation to preserve motor and language functions. The clinical history and extensive workup prior to surgery is discussed as well as the opportunity to compare the cortical maps for language, motor, and sensory function before each resection. Reorganization in cortical tongue sensory areas was seen concomitant with a new zone of ictal and interictal activity in the previous tongue sensory area. Detailed neuropsychological data is presented before and after any surgical intervention to hypothesize about the extent of reorganization between epochs. We conclude that intrahemispheric cortical plasticity does occur following frontal lobe resective surgery in a teenager with medically refractory seizures. PMID:24961623

  4. Organizing Principles of Human Cortical Development--Thickness and Area from 4 to 30 Years: Insights from Comparative Primate Neuroanatomy.

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    Amlien, Inge K; Fjell, Anders M; Tamnes, Christian K; Grydeland, Håkon; Krogsrud, Stine K; Chaplin, Tristan A; Rosa, Marcello G P; Walhovd, Kristine B

    2016-01-01

    The human cerebral cortex undergoes a protracted, regionally heterogeneous development well into young adulthood. Cortical areas that expand the most during human development correspond to those that differ most markedly when the brains of macaque monkeys and humans are compared. However, it remains unclear to what extent this relationship derives from allometric scaling laws that apply to primate brains in general, or represents unique evolutionary adaptations. Furthermore, it is unknown whether the relationship only applies to surface area (SA), or also holds for cortical thickness (CT). In 331 participants aged 4 to 30, we calculated age functions of SA and CT, and examined the correspondence of human cortical development with macaque to human expansion, and with expansion across nonhuman primates. CT followed a linear negative age function from 4 to 30 years, while SA showed positive age functions until 12 years with little further development. Differential cortical expansion across primates was related to regional maturation of SA and CT, with age trajectories differing between high- and low-expanding cortical regions. This relationship adhered to allometric scaling laws rather than representing uniquely macaque-human differences: regional correspondence with human development was as large for expansion across nonhuman primates as between humans and macaque.

  5. Neurons controlling voluntary vocalization in the macaque ventral premotor cortex.

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    Gino Coudé

    Full Text Available The voluntary control of phonation is a crucial achievement in the evolution of speech. In humans, ventral premotor cortex (PMv and Broca's area are known to be involved in voluntary phonation. In contrast, no neurophysiological data are available about the role of the oro-facial sector of nonhuman primates PMv in this function. In order to address this issue, we recorded PMv neurons from two monkeys trained to emit coo-calls. Results showed that a population of motor neurons specifically fire during vocalization. About two thirds of them discharged before sound onset, while the remaining were time-locked with it. The response of vocalization-selective neurons was present only during conditioned (voluntary but not spontaneous (emotional sound emission. These data suggest that the control of vocal production exerted by PMv neurons constitutes a newly emerging property in the monkey lineage, shedding light on the evolution of phonation-based communication from a nonhuman primate species.

  6. Cortical activation by tactile stimulation to face and anterior neck areas: an fMRI study with three analytic methods.

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    Lin, Chou-Ching K; Sun, Yung-Nien; Huang, Chung-I; Yu, Chin-Yin; Ju, Ming-Shaung

    2010-12-01

    The main purpose of this study was to investigate the sensory cortical activation of the anterior neck region and the relationship between the neck and face representation areas. Functional MRI by blood oxygenation level dependent measurements was performed while tactile stimulation was applied to the face or neck area. Nonpainful tactile stimuli were manually delivered by an experimenter at a frequency of ∼1 Hz. Block (epoch) design was adopted with a block duration of 30 s and a whole run duration of 6 min. For each location, two runs were performed. After the image data were preprocessed, both parameteric and nonparametric methods were performed to test the group results. The results showed that (1) unilateral face or neck stimulation could elicit bilateral cortical activation, (2) mainly the face representation and face-hand junction areas, but not the conventional neck representation area, were activated by face or neck stimulation, and (3) the activation areas were larger when right face or neck was stimulated. In conclusion, the sensory cortical representation area of the anterior neck region was mainly at the junction of hand and face representation area and the activated area was larger when the right face or neck was stimulated.

  7. Cortical Motor Circuits after Piano Training in Adulthood: Neurophysiologic Evidence.

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    Houdayer, Elise; Cursi, Marco; Nuara, Arturo; Zanini, Sonia; Gatti, Roberto; Comi, Giancarlo; Leocani, Letizia

    2016-01-01

    The neuronal mechanisms involved in brain plasticity after skilled motor learning are not completely understood. We aimed to study the short-term effects of keyboard training in music-naive subjects on the motor/premotor cortex activity and interhemispheric interactions, using electroencephalography and transcranial magnetic stimulation (TMS). Twelve subjects (experimental group) underwent, before and after a two week-piano training: (1) hand-motor function tests: Jamar, grip and nine-hole peg tests; (2) electroencephalography, evaluating the mu rhythm task-related desynchronization (TRD) during keyboard performance; and (3) TMS, targeting bilateral abductor pollicis brevis (APB) and abductor digiti minimi (ADM), to obtain duration and area of ipsilateral silent period (ISP) during simultaneous tonic contraction of APB and ADM. Data were compared with 13 controls who underwent twice these measurements, in a two-week interval, without undergoing piano training. Every subject in the experimental group improved keyboard performance and left-hand nine-hole peg test scores. Pre-training, ISP durations were asymmetrical, left being longer than right. Post-training, right ISPAPB increased, leading to symmetrical ISPAPB. Mu TRD during motor performance became more focal and had a lesser amplitude than in pre-training, due to decreased activity over ventral premotor cortices. No such changes were evidenced in controls. We demonstrated that a 10-day piano-training was associated with balanced interhemispheric interactions both at rest and during motor activation. Piano training, in a short timeframe, may reshape local and inter-hemispheric motor cortical circuits.

  8. Multiple bout rTMS on spatial working memory: a comparison study of two cortical areas.

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    Pearce, Alan J; Lum, Jarrad A G; Seth, Sunaina; Rafael, Olivia; Hsu, Chia-Ming K; Drury, Hannah G K; Tooley, Gregory A

    2014-07-01

    It has been established that acute (within-session) repetitive transcranial magnetic stimulation (rTMS) improves spatial working memory (SWM). However, questions remain regarding the safety and effectiveness of multiple bouts of rTMS and the optimal cortical area to stimulate. This preliminary study investigated, in healthy participants, multiple bouts of rTMS over the dorsolateral pre-frontal cortex (DLPFC), or posterior parietal cortex (PPC) on SWM. Twenty participants (10m, 10f), all naïve to rTMS, where randomized into a DLPFC or PPC group, receiving six sessions of rTMS (5Hz at 80% of motor threshold) every second day over two weeks. Prior to and post rTMS bouts, all participants completed testing for SWM measuring individuals' accuracy, strategy, and speed. Following repeated bouts of rTMS, significant improvements were observed with no contraindications in stimulating PPC but not DLPFC. This preliminary study has demonstrated that repeated rTMS bouts improve SWM safety providing potential for clinical application.

  9. Distinct neural patterns enable grasp types decoding in monkey dorsal premotor cortex

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    Hao, Yaoyao; Zhang, Qiaosheng; Controzzi, Marco; Cipriani, Christian; Li, Yue; Li, Juncheng; Zhang, Shaomin; Wang, Yiwen; Chen, Weidong; Chiara Carrozza, Maria; Zheng, Xiaoxiang

    2014-12-01

    Objective. Recent studies have shown that dorsal premotor cortex (PMd), a cortical area in the dorsomedial grasp pathway, is involved in grasp movements. However, the neural ensemble firing property of PMd during grasp movements and the extent to which it can be used for grasp decoding are still unclear. Approach. To address these issues, we used multielectrode arrays to record both spike and local field potential (LFP) signals in PMd in macaque monkeys performing reaching and grasping of one of four differently shaped objects. Main results. Single and population neuronal activity showed distinct patterns during execution of different grip types. Cluster analysis of neural ensemble signals indicated that the grasp related patterns emerged soon (200-300 ms) after the go cue signal, and faded away during the hold period. The timing and duration of the patterns varied depending on the behaviors of individual monkey. Application of support vector machine model to stable activity patterns revealed classification accuracies of 94% and 89% for each of the two monkeys, indicating a robust, decodable grasp pattern encoded in the PMd. Grasp decoding using LFPs, especially the high-frequency bands, also produced high decoding accuracies. Significance. This study is the first to specify the neuronal population encoding of grasp during the time course of grasp. We demonstrate high grasp decoding performance in PMd. These findings, combined with previous evidence for reach related modulation studies, suggest that PMd may play an important role in generation and maintenance of grasp action and may be a suitable locus for brain-machine interface applications.

  10. Long-range neural activity evoked by premotor cortex stimulation: a TMS/EEG co-registration study

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    Marco eZanon

    2013-11-01

    Full Text Available The premotor cortex is one of the fundamental structures composing the neural networks of the human brain. It is implicated in many behaviors and cognitive tasks, ranging from movement to attention and eye-related activity. Therefore, neural circuits that are related to premotor cortex have been studied to clarify their connectivity and/or role in different tasks. In the present work, we aimed to investigate the propagation of the neural activity evoked in the dorsal premotor cortex using transcranial magnetic stimulation/electroencephalography (TMS/EEG. Towards this end, interest was focused on the neural dynamics elicited in long-ranging temporal and spatial networks. Twelve healthy volunteers underwent a single-pulse TMS protocol in a resting condition with eyes closed, and the evoked activity, measured by EEG, was compared to a sham condition in a time window ranging from 45 msec to about 200 msec after TMS. Spatial and temporal investigations were carried out with sLORETA. TMS was found to induce propagation of neural activity mainly in the contralateral sensorimotor and frontal cortices, at about 130 msec after delivery of the stimulus. Different types of analyses showed propagated activity also in posterior, mainly visual, regions, in a time window between 70 and 130 msec. Finally, a likely rebounding activation of the sensorimotor and frontal regions, was observed in various time ranges. Taken together, the present findings further characterize the neural circuits that are driven by dorsal premotor cortex activation in healthy humans.

  11. Alternative Stimulation Intensities for Mapping Cortical Motor Area with Navigated TMS.

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    Kallioniemi, Elisa; Julkunen, Petro

    2016-05-01

    Navigated transcranial magnetic stimulation (nTMS) is becoming a popular tool in pre-operative mapping of functional motor areas. The stimulation intensities used in the mapping are commonly suprathreshold intensities with respect to the patient's resting motor threshold (rMT). There is no consensus on which suprathreshold intensity should be used nor on the optimal criteria for selecting the appropriate stimulation intensity (SI). In this study, the left motor cortices of 12 right-handed volunteers (8 males, age 24-61 years) were mapped using motor evoked potentials with an SI of 110 and 120 % of rMT and with an upper threshold (UT) estimated by the Mills-Nithi algorithm. The UT was significantly lower than 120 % of rMT (p rMT (p = 0.112). The representation sizes followed a similar trend, i.e. areas computed based on UT (5.9 cm(2)) and 110 % of rMT (5.0 cm(2)) being smaller than that of 120 % of rMT (8.8 cm(2)) (p ≤ 0.001). There was no difference in representation sizes between 110 % of rMT and UT. The variance in representation size was found to be significantly lower with UT compared to 120 % of rMT (p = 0.048, uncorrected), while there was no difference between 110 % of rMT and UT or 120 % of rMT. Indications of lowest inter-individual variation in representation size were observed with UT; this is possibly due to the fact that it takes into account the individual input-output characteristics of the motor cortex. Therefore, the UT seems to be a good option for SI in motor mapping applications to outline functional motor areas with nTMS and it could potentially reduce the inter-individual variation caused by the selection of SI in motor mapping in pre-surgical applications and radiosurgery planning.

  12. Evolution of mammalian sensorimotor cortex: Thalamic projections to parietal cortical areas in Monodelphis domestica

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    James Clinton Dooley

    2015-01-01

    Full Text Available The current experiments build upon previous studies designed to reveal the network of parietal cortical areas present in the common mammalian ancestor. Understanding this ancestral network is essential for highlighting the basic somatosensory circuitry present in all mammals, and how this basic plan was modified to generate species specific behaviors. Our animal model, the short-tailed opossum (Monodelphis domestica, is a South American marsupial that has been proposed to have a similar ecological niche and morphology to the earliest common mammalian ancestor. In this investigation, we injected retrograde neuroanatomical tracers into the face and body representations of primary somatosensory cortex (S1, the rostral and caudal somatosensory fields (SR and SC, as well as a multimodal region (MM. Projections from different architectonically defined thalamic nuclei were then quantified. Our results provide further evidence to support the hypothesized basic mammalian plan of thalamic projections to S1, with the lateral and medial ventral posterior thalamic nuclei (VPl and VPm projecting to S1 body and S1 face, respectively. Additional strong projections are from the medial division of posterior nucleus (Pom. SR receives projections from several midline nuclei, including the medial dorsal, ventral medial nucleus, and Pom. SC and MM show similar patterns of connectivity, with projections from the ventral anterior and ventral lateral nuclei, VPm and VPl, and the entire posterior nucleus (medial and lateral. Notably, MM is distinguished from SC by relatively dense projections from the dorsal division of the lateral geniculate nucleus and pulvinar. We discuss the finding that S1 of the short-tailed opossum has a similar pattern of projections as other marsupials and mammals, but also some distinct projections not present in other mammals. Further we provide additional support for a primitive posterior parietal cortex which receives input from multiple

  13. Improved Discriminability of Spatiotemporal Neural Patterns in Rat Motor Cortical Areas as Directional Choice Learning Progresses

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    Hongwei eMao

    2015-03-01

    Full Text Available Animals learn to choose a proper action among alternatives to improve their odds of success in food foraging and other activities critical for survival. Through trial-and-error, they learn correct associations between their choices and external stimuli. While a neural network that underlies such learning process has been identified at a high level, it is still unclear how individual neurons and a neural ensemble adapt as learning progresses. In this study, we monitored the activity of single units in the rat medial and lateral agranular (AGm and AGl, respectively areas as rats learned to make a left or right side lever press in response to a left or right side light cue. We noticed that rat movement parameters during the performance of the directional choice task quickly became stereotyped during the first 2-3 days or sessions. But learning the directional choice problem took weeks to occur. Accompanying rats’ behavioral performance adaptation, we observed neural modulation by directional choice in recorded single units. Our analysis shows that ensemble mean firing rates in the cue-on period did not change significantly as learning progressed, and the ensemble mean rate difference between left and right side choices did not show a clear trend of change either. However, the spatiotemporal firing patterns of the neural ensemble exhibited improved discriminability between the two directional choices through learning. These results suggest a spatiotemporal neural coding scheme in a motor cortical neural ensemble that may be responsible for and contributing to learning the directional choice task.

  14. Glial tumors in brodmann area 6: spread pattern and relationships to motor areas.

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    Shah, Komal B; Hayman, L Anne; Chavali, Lakshmi S; Hamilton, Jackson D; Prabhu, Sujit S; Wangaryattawanich, Pattana; Kumar, Vinodh A; Kumar, Ashok J

    2015-01-01

    The posterior frontal lobe of the brain houses Brodmann area 4, which is the primary motor cortex, and Brodmann area 6, which consists of the supplementary motor area on the medial portion of the hemisphere and the premotor cortex on the lateral portion. In this area, safe resection is dependent on accurate localization of the motor cortex and the central sulcus, which can usually be achieved by using thin-section imaging and confirmed by using other techniques. The most reliable anatomic landmarks are the "hand knob" area and the marginal ramus of the cingulate sulcus. Postoperatively, motor deficits can occur not only because of injury to primary motor cortex but also because of injury to the supplementary motor area. Unlike motor cortex injury, the supplementary motor area syndrome is transient, if it occurs at all. On the lateral hemisphere, motor and language deficits can also occur because of premotor cortex injury, but a dense motor deficit would indicate subcortical injury to the corticospinal tract. The close relationship of the subcortical motor fibers and premotor cortex is illustrated. In contrast to the more constant landmarks of the central sulcus and marginal ramus, which aid in preoperative localization, the variable interruptions in the precentral and cingulate sulci of the posterior frontal lobe seem to provide "cortical bridges" for spread of infiltrating gliomas. (©)RSNA, 2015.

  15. Characterization of Cortical Networks and Corticocortical Functional Connectivity Mediating Arbitrary Visuomotor Mapping.

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    Brovelli, Andrea; Chicharro, Daniel; Badier, Jean-Michel; Wang, Huifang; Jirsa, Viktor

    2015-09-16

    Adaptive behaviors are built on the arbitrary linkage of sensory inputs to actions and goals. Although the sensorimotor and associative frontostriatal circuits are known to mediate arbitrary visuomotor mappings, the underlying corticocortico dynamics remain elusive. Here, we take a novel approach exploiting gamma-band neural activity to study the human cortical networks and corticocortical functional connectivity mediating arbitrary visuomotor mapping. Single-trial gamma-power time courses were estimated for all Brodmann areas by combing magnetoencephalographic and MRI data with spectral analysis and beam-forming techniques. Linear correlation and Granger causality analyses were performed to investigate functional connectivity between cortical regions. The performance of visuomotor associations was characterized by an increase in gamma-power and functional connectivity over the sensorimotor and frontoparietal network, in addition to medial prefrontal areas. The superior parietal area played a driving role in the network, exerting Granger causality on the dorsal premotor area. Premotor areas acted as relay from parietal to medial prefrontal cortices, which played a receiving role in the network. Link community analysis further revealed that visuomotor mappings reflect the coordination of multiple subnetworks with strong overlap over motor and frontoparietal areas. We put forward an associative account of the underlying cognitive processes and corticocortical functional connectivity. Overall, our approach and results provide novel perspectives toward a better understanding of how distributed brain activity coordinates adaptive behaviors. In everyday life, most of our behaviors are based on the arbitrary linkage of sensory information to actions and goals, such as stopping at a red traffic light. Despite their automaticity, such behaviors rely on the activity of a large brain network and elusive interareal functional connectivity. We take a novel approach exploiting

  16. Involvement of the human dorsal premotor cortex in unimanual motor control: an interference approach using transcranial magnetic stimulation.

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    Cincotta, Massimo; Borgheresi, Alessandra; Balestrieri, Fabrizio; Giovannelli, Fabio; Rossi, Simone; Ragazzoni, Aldo; Zaccara, Gaetano; Ziemann, Ulf

    2004-09-02

    Unilateral movements are enabled through a distributed network of motor cortical areas but the relative contribution from the parts of this network is largely unknown. Failure of this network potentially results in mirror activation of the primary motor cortex (M1) ipsilateral to the intended movement. Here we tested the role of the right dorsal premotor cortex (dPMC) in 11 healthy subjects by disrupting its activity with 20 Hz repetitive transcranial magnetic stimulation (rTMS) whilst the subjects exerted a unilateral contraction of the left first dorsal interosseous (FDI). We found that disruption of right dPMC enhanced mirror activation of the ipsilateral left M1, as probed by motor evoked potential (MEP) amplitude to the right FDI. This was not the case with sham rTMS, when rTMS was directed to the right M1, or with rTMS of the right dPMC but without contraction of the left FDI. Findings suggest that activity in the dPMC contributes to the suppression of mirror movements during intended unilateral movements.

  17. Motor area localization using fMRI-constrained cortical current density reconstruction of movement-related cortical potentials, a comparison with fMRI and TMS mapping.

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    Inuggi, Alberto; Filippi, Massimo; Chieffo, Raffaella; Agosta, Federica; Rocca, Maria A; González-Rosa, Javier J; Cursi, Marco; Comi, Giancarlo; Leocani, Letizia

    2010-01-13

    The localization of human hand primary motor area (M1) has been the object of several studies during the last decades. EEG source analysis, functional magnetic resonance imaging (fMRI) and focal transcranial magnetic stimulation (TMS) are non-invasive methods for localizing M1 with good accuracy compared to direct electrocorticography (ECoG) results. EEG sources were reconstructed with Cortical Current Density (CCD) method, allowing to evaluate simultaneous and distributed patterns of activation and to increase accuracy by constraining on information derived from fMRI (fMRI-CCD). The aim of this study was to compare the M1 contribution of movement-related cortical potentials (MRCP) with TMS and fMRI results and to test the effect of constraints strength, algorithm norm and localization methods over CCD reconstruction. Seven right-handed healthy subjects underwent 64-channel EEG recording of MRCP to right thumb movement, focal TMS mapping of the right abductor pollicis brevis muscle and fMRI during right hand movement. We found fMRI activations, EEG sources and TMS mapping corresponding to the anatomical landmark of the hand area in all subjects with fMRI and TMS center-of-gravity and in almost all subjects using fMRI-CCD with moderate constraint. A significant improvement was found using fMRI-CCD compared to CCD alone. This study confirms the usefulness of multimodal integration of fMRI, EEG and TMS in localizing M1 and the possibility to increase EEG spatial resolution using fMRI information.

  18. Coherent delta-band oscillations between cortical areas correlate with decision making

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    Nácher, Verónica; Ledberg, Anders; Deco, Gustavo; Romo, Ranulfo

    2013-01-01

    Coherent oscillations in the theta-to-gamma frequency range have been proposed as a mechanism that coordinates neural activity in large-scale cortical networks in sensory, motor, and cognitive tasks. Whether this mechanism also involves coherent oscillations at delta frequencies (1–4 Hz) is not known. Rather, delta oscillations have been associated with slow-wave sleep. Here, we show coherent oscillations in the delta frequency band between parietal and frontal cortices during the decision-making component of a somatosensory discrimination task. Importantly, the magnitude of this delta-band coherence is modulated by the different decision alternatives. Furthermore, during control conditions not requiring decision making, delta-band coherences are typically much reduced. Our work indicates an important role for synchronous activity in the delta frequency band when large-scale, distant cortical networks coordinate their neural activity during decision making. PMID:23980180

  19. Coherent delta-band oscillations between cortical areas correlate with decision making.

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    Nácher, Verónica; Ledberg, Anders; Deco, Gustavo; Romo, Ranulfo

    2013-09-10

    Coherent oscillations in the theta-to-gamma frequency range have been proposed as a mechanism that coordinates neural activity in large-scale cortical networks in sensory, motor, and cognitive tasks. Whether this mechanism also involves coherent oscillations at delta frequencies (1-4 Hz) is not known. Rather, delta oscillations have been associated with slow-wave sleep. Here, we show coherent oscillations in the delta frequency band between parietal and frontal cortices during the decision-making component of a somatosensory discrimination task. Importantly, the magnitude of this delta-band coherence is modulated by the different decision alternatives. Furthermore, during control conditions not requiring decision making, delta-band coherences are typically much reduced. Our work indicates an important role for synchronous activity in the delta frequency band when large-scale, distant cortical networks coordinate their neural activity during decision making.

  20. Neuroimaging in pre-motor Parkinson's disease

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    Thomas R. Barber

    2017-01-01

    Full Text Available The process of neurodegeneration in Parkinson's disease begins long before the onset of clinical motor symptoms, resulting in substantial cell loss by the time a diagnosis can be made. The period between the onset of neurodegeneration and the development of motoric disease would be the ideal time to intervene with disease modifying therapies. This pre-motor phase can last many years, but the lack of a specific clinical phenotype means that objective biomarkers are needed to reliably detect prodromal disease. In recent years, recognition that patients with REM sleep behaviour disorder (RBD are at particularly high risk of future parkinsonism has enabled the development of large prodromal cohorts in which to investigate novel biomarkers, and neuroimaging has generated some of the most promising results to date. Here we review investigations undertaken in RBD and other pre-clinical cohorts, including modalities that are well established in clinical Parkinson's as well as novel imaging methods. Techniques such as high resolution MRI of the substantia nigra and functional imaging of Parkinsonian brain networks have great potential to facilitate early diagnosis. Further longitudinal studies will establish their true value in quantifying prodromal neurodegeneration and predicting future Parkinson's.

  1. Isolation of locally derived stem/progenitor cells from the peri-infarct area that do not migrate from the lateral ventricle after cortical stroke.

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    Shimada, Issei S; Peterson, Brittni M; Spees, Jeffrey L

    2010-09-01

    Neurogenesis can arise from neural stem/progenitor cells of the subventricular zone after strokes involving both the cortex and striatum. However, it is controversial whether all types of stroke and strokes of different sizes activate neurogenesis from the subventricular zone niche. In contrast with cortical/striatal strokes, repair and remodeling after mild cortical strokes may involve to a greater extent local cortical stem/progenitor cells and cells from nonneurogenic niches. We compared stem/progenitor cell responses after focal cortical strokes produced by distal middle cerebral artery occlusion and cortical/striatal strokes produced by the intraluminal suture model. To label migrating neuroblasts from the subventricular zone, we injected DiI to the lateral ventricle after distal middle cerebral artery occlusion. By immunohistochemistry, we characterized cells expressing stem/progenitor cell markers in the peri-infarct area. We isolated cortical stem/progenitor cells from the peri-infarct area after distal middle cerebral artery occlusion and assayed their self-renewal and differentiation capacity. In contrast with cortical/striatal strokes, focal cortical strokes did not induce neuroblast migration from the subventricular zone to the infarct zone after distal middle cerebral artery occlusion. By immunohistochemistry, we observed subpopulations of reactive astrocytes in the peri-infarct area that coexpressed radial glial cell markers such as Sox2, Nestin, and RC2. Clonal neural spheres isolated from the peri-infarct area after distal middle cerebral artery occlusion differentiated into neurons, astrocytes, oligodendrocytes, and smooth muscle cells. Notably, neural spheres isolated from the peri-infarct area also expressed RC2 before differentiation. Mild cortical strokes that do not penetrate the striatum activate local cortical stem/progenitor cells but do not induce neuroblast migration from the subventricular zone niche.

  2. Constraint-Induced Movement Therapy Combined with Transcranial Direct Current Stimulation over Premotor Cortex Improves Motor Function in Severe Stroke: A Pilot Randomized Controlled Trial

    Science.gov (United States)

    Batista, Larissa M.; Nogueira, Lídia L. R. F.; de Oliveira, Eliane A.; de Carvalho, Antonio G. C.; Lima, Soriano S.; Santana, Jordânia R. M.; de Lima, Emerson C. C.; Fernández-Calvo, Bernardino

    2017-01-01

    Objective. We compared the effects of transcranial direct current stimulation at different cortical sites (premotor and motor primary cortex) combined with constraint-induced movement therapy for treatment of stroke patients. Design. Sixty patients were randomly distributed into 3 groups: Group A, anodal stimulation on premotor cortex and constraint-induced movement therapy; Group B, anodal stimulation on primary motor cortex and constraint-induced movement therapy; Group C, sham stimulation and constraint-induced movement therapy. Evaluations involved analysis of functional independence, motor recovery, spasticity, gross motor function, and muscle strength. Results. A significant improvement in primary outcome (functional independence) after treatment in the premotor group followed by primary motor group and sham group was observed. The same pattern of improvement was highlighted among all secondary outcome measures regarding the superior performance of the premotor group over primary motor and sham groups. Conclusions. Premotor cortex can contribute to motor function in patients with severe functional disabilities in early stages of stroke. This study was registered in ClinicalTrials.gov database (NCT 02628561). PMID:28250992

  3. Constraint-Induced Movement Therapy Combined with Transcranial Direct Current Stimulation over Premotor Cortex Improves Motor Function in Severe Stroke: A Pilot Randomized Controlled Trial.

    Science.gov (United States)

    Andrade, Suellen M; Batista, Larissa M; Nogueira, Lídia L R F; de Oliveira, Eliane A; de Carvalho, Antonio G C; Lima, Soriano S; Santana, Jordânia R M; de Lima, Emerson C C; Fernández-Calvo, Bernardino

    2017-01-01

    Objective. We compared the effects of transcranial direct current stimulation at different cortical sites (premotor and motor primary cortex) combined with constraint-induced movement therapy for treatment of stroke patients. Design. Sixty patients were randomly distributed into 3 groups: Group A, anodal stimulation on premotor cortex and constraint-induced movement therapy; Group B, anodal stimulation on primary motor cortex and constraint-induced movement therapy; Group C, sham stimulation and constraint-induced movement therapy. Evaluations involved analysis of functional independence, motor recovery, spasticity, gross motor function, and muscle strength. Results. A significant improvement in primary outcome (functional independence) after treatment in the premotor group followed by primary motor group and sham group was observed. The same pattern of improvement was highlighted among all secondary outcome measures regarding the superior performance of the premotor group over primary motor and sham groups. Conclusions. Premotor cortex can contribute to motor function in patients with severe functional disabilities in early stages of stroke. This study was registered in ClinicalTrials.gov database (NCT 02628561).

  4. Constraint-Induced Movement Therapy Combined with Transcranial Direct Current Stimulation over Premotor Cortex Improves Motor Function in Severe Stroke: A Pilot Randomized Controlled Trial

    Directory of Open Access Journals (Sweden)

    Suellen M. Andrade

    2017-01-01

    Full Text Available Objective. We compared the effects of transcranial direct current stimulation at different cortical sites (premotor and motor primary cortex combined with constraint-induced movement therapy for treatment of stroke patients. Design. Sixty patients were randomly distributed into 3 groups: Group A, anodal stimulation on premotor cortex and constraint-induced movement therapy; Group B, anodal stimulation on primary motor cortex and constraint-induced movement therapy; Group C, sham stimulation and constraint-induced movement therapy. Evaluations involved analysis of functional independence, motor recovery, spasticity, gross motor function, and muscle strength. Results. A significant improvement in primary outcome (functional independence after treatment in the premotor group followed by primary motor group and sham group was observed. The same pattern of improvement was highlighted among all secondary outcome measures regarding the superior performance of the premotor group over primary motor and sham groups. Conclusions. Premotor cortex can contribute to motor function in patients with severe functional disabilities in early stages of stroke. This study was registered in ClinicalTrials.gov database (NCT 02628561.

  5. Linking Electrical Stimulation of Human Primary Visual Cortex, Size of Affected Cortical Area, Neuronal Responses, and Subjective Experience.

    Science.gov (United States)

    Winawer, Jonathan; Parvizi, Josef

    2016-12-21

    Electrical brain stimulation (EBS) complements neural measurements by probing the causal relationship between brain and perception, cognition, and action. Many fundamental questions about EBS remain unanswered, including the spatial extent of cortex responsive to stimulation, and the relationship between the circuitry engaged by EBS and the types of neural responses elicited by sensory stimulation. Here, we measured neural responses and the effects of EBS in primary visual cortex in four patients implanted with intracranial electrodes. Using stimulation, behavior, and retinotopic mapping, we show the relationship between the size of affected cortical area and the magnitude of electrical charge. Furthermore, we show that the spatial location of electrically induced visual sensations is matched to the receptive field of the cortical site measured with broadband field potentials, and less so with event related potentials. Together, these findings broaden our knowledge about the mechanism of EBS and the neuromodulation of the human brain. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Cortical projections to the human red nucleus: a diffusion tensor tractography study with a 1.5-T MRI machine

    Energy Technology Data Exchange (ETDEWEB)

    Habas, Christophe; Cabanis, Emmanuel Alain [Universite Pierre et Marie Curie Paris 6, Service de Neuroimagerie, Centre Hospitalier National d' Optalmologie des Quinze-Vingts, Paris (France)

    2006-10-15

    Previous studies in apes and monkeys have shown that the red nucleus receives projections from the sensorimotor and premotor cortices, whereas other experiments carried out with injured human brains have found corticorubral projections issuing from associative areas. Therefore, we reassessed in vivo the human anatomical projections from the cerebral cortex to the red nucleus using diffusion tensor imaging (DTI) axonal tracking. The connectivity between the cerebral cortex and the red nuclei of seven volunteers was studied at 1.5 T using streamlined DTI axonal tracking. Trajectories were constantly tracked between the red nuclei and the ipsilateral pericentral and prefrontal cortices, as well as the temporal cortex and the striatum in two subjects. Within the cerebral trunk, trajectories also include the superior cerebellar peduncle and the central tegmental tract. The human red nucleus receives its main afferences from the sensorimotor and prefrontal cortices. (orig.)

  7. The contribution of brain sub-cortical loops in the expression and acquisition of action understanding abilities☆

    Science.gov (United States)

    Caligiore, Daniele; Pezzulo, Giovanni; Miall, R. Chris; Baldassarre, Gianluca

    2013-01-01

    Research on action understanding in cognitive neuroscience has led to the identification of a wide “action understanding network” mainly encompassing parietal and premotor cortical areas. Within this cortical network mirror neurons are critically involved implementing a neural mechanism according to which, during action understanding, observed actions are reflected in the motor patterns for the same actions of the observer. We suggest that focusing only on cortical areas and processes could be too restrictive to explain important facets of action understanding regarding, for example, the influence of the observer's motor experience, the multiple levels at which an observed action can be understood, and the acquisition of action understanding ability. In this respect, we propose that aside from the cortical action understanding network, sub-cortical processes pivoting on cerebellar and basal ganglia cortical loops could crucially support both the expression and the acquisition of action understanding abilities. Within the paper we will discuss how this extended view can overcome some limitations of the “pure” cortical perspective, supporting new theoretical predictions on the brain mechanisms underlying action understanding that could be tested by future empirical investigations. PMID:23911926

  8. Two-dimensional map of direction selectivity in cortical visual area MT of Cebus monkey

    Directory of Open Access Journals (Sweden)

    ANTONIA CINIRA M. DIOGO

    2002-09-01

    Full Text Available We studied the spatial organization of direction of motion in visual area MT of the Cebus apella monkey. We used arrays of 6 (700 µm apart parallel electrodes in penetrations tangential to the cortical layers to record multi-unit responses to moving bars, at 200 µm steps. We determined the direction selectivity at each recording site. The data from single penetrations showed cyclic and gradual changes in the direction selectivity of clusters of cells, intermixed with abrupt 180º discontinuities along the electrode track. In order to obtain maps of direction of motion selectivity, we examined the spatial distribution of direction of motion in MT and we applied a method to determine the location of the centers of radial arrangements of direction selectivity. This tangential organization is characterized by slow continuous changes in direction of motion, interrupted by discontinuities. The changes in direction selectivity are organized radially in a pinwheel fashion and in slabs of linear variation. The pinwheel arrangements have 800-1400 µm in diameter. The size of the radial arrangement is comparable to the point image size in area MT at each eccentricity.Estudamos a organização espacial da seletividade ao sentido do movimento na área visual MT do macaco Cebus apella. Utilizamos um arranjo de 6 eletródios paralelos (separados por 700µm em penetrações tangenciais às camadas corticais para registrar, a cada 200µm, a atividade multi-unitária em resposta a barras em movimento. Determinamos a seletividade ao sentido de movimento em cada sítio de registro. Os dados captados por um único eletródio mostraram uma mudança cíclica e gradual na seletividade ao sentido de movimento dos grupos de neurônios registrados ao longo da trajetória do eletródio, interrompida por mudanças abruptas de 180º ocasionando descontinuidades na seletividade ao sentido do movimento. Para obter mapas de seletividade ao sentido do movimento, examinamos a

  9. Two-wave behavior under various conditions of transition area from cancellous bone to cortical bone.

    Science.gov (United States)

    Nagatani, Yoshiki; Mizuno, Katsunori; Matsukawa, Mami

    2014-07-01

    The two-wave phenomenon, the wave separation of a single ultrasonic pulse in cancellous bone, is expected to be a useful tool for the diagnosis of osteoporosis. However, because actual bone has a complicated structure, precise studies on the effect of transition conditions between cortical and cancellous parts are required. This study investigated how the transition condition influenced the two-wave generation using three-dimensional X-ray CT images of an equine radius and a three-dimensional simulation technique. As a result, any changes in the boundary between cortical part and trabecular part, which gives the actual complex structure of bone, did not eliminate the generation of either the primary wave or the secondary wave at least in the condition of clear trabecular alignment. The results led us to the possibility of using the two-wave phenomenon in a diagnostic system for osteoporosis in cases of a complex boundary.

  10. Dorsal premotor cortex and conditional movement selection: A PET functional mapping study.

    Science.gov (United States)

    Grafton, S T; Fagg, A H; Arbib, M A

    1998-02-01

    Positron emission tomography (PET) brain mapping was used to investigate whether or not human dorsal premotor cortex is involved in selecting motor acts based on arbitrary visual stimuli. Normal subjects performed four movement selection tasks. A manipulandum with three graspable stations was used. An imperative visual cue (LEDs illuminated in random order) indicated which station to grasp next with no instructional delay period. In a power task, a large aperture power grip was used for all trials, irrespective of the LED color. In a precision task, a pincer grasp of thumb and index finger was used. In a conditional task, the type of grasp (power or precision) was randomly determined by LED color. Comparison of the conditional selection task versus the average of the power and precision tasks revealed increased blood flow in left dorsal premotor cortex and superior parietal lobule. The average rate of producing the different grasp types and transport to the manipulandum stations was equivalent across this comparison, minimizing the contribution of movement attributes such as planning the individual movements (as distinct from planning associated with use of instructional stimuli), kinematics, or direction of target or limb movement. A comparison of all three movement tasks versus a rest task identified movement related activity involving a large area of central, precentral and postcentral cortex. In the region of the precentral sulcus movement related activity was located immediately caudal to the area activated during selection. The results establish a role for human dorsal premotor cortex and superior parietal cortex in selecting stimulus guided movements and suggest functional segregation within dorsal premotor cortex.

  11. Interhemispheric Connections between the Primary Visual Cortical Areas via the Anterior Commissure in Human Callosal Agenesis

    OpenAIRE

    van Meer, Nathalie; Houtman, Anne C.; Van Schuerbeek, Peter; Vanderhasselt, Tim; Milleret, Chantal; ten Tusscher, Marcel P.

    2016-01-01

    Aim: In humans, images in the median plane of the head either fall on both nasal hemi-retinas or on both temporal hemi-retinas. Interhemispheric connections allow cortical cells to have receptive fields on opposite sides. The major interhemispheric connection, the corpus callosum, is implicated in central stereopsis and disparity detection in front of the fixation plane. Yet individuals with agenesis of the corpus callosum may show normal stereopsis and disparity vergence. We set out to study...

  12. Functional localization of the cortical motor area in the brain Electrocorticogram analysis

    Institute of Scientific and Technical Information of China (English)

    Tao Jiang; Xiaoming Wu; Binggang Ye; Sijuan Huang

    2010-01-01

    The method for rapidly,precisely and non-invasively localizing functional regions of the brain is a problem in neuromedicine research.Cortical electrostimulation is the optimal localization method during brain surgery,with a degree of accuracy of approximately 5 mm.However,electrostimulation can damage the cerebral cortex,trigger epilepsy,and extend the operation time.Studies are required to determine whether cortical motor regions can be localized by wavelet analysis from electrocorticograms.In this study,based on wavelet analysis of electrocorticograms,a selection of algorithms for classification of the mu rhythm in the motor regions utilizing experimental data was verified.Results demonstrated that a characteristic quantity of energy ratio in the reconstructed signal was filtered in the d6(7.81-15.62 Hz)band prior to and following motion events.A characteristic threshold was considered to be 40%.The accuracy of localization detection was 93%.The degree of accuracy was less than 5 mm.The present study avoided the problems of cerebral cortex injury and epilepsy onset,with an operation time of 60 seconds.Therefore,wavelet analysis on electrocorticogram is feasible for localizing cortical motor regions.Furthermore,this localization technique is accurate,safe and rapid.

  13. Different distal-proximal movement balances in right- and left-hand writing may hint at differential premotor cortex involvement

    NARCIS (Netherlands)

    Potgieser, A. R. E.; de Jong, B. M.

    2011-01-01

    Right-handed people generally write with their right hand. Language expressed in script is thus performed with the hand also preferred for skilled motor tasks. This may suggest an efficient functional interaction between the language area of Broca and the adjacent ventral premotor cortex (PMv) in th

  14. Different distal-proximal movement balances in right- and left-hand writing may hint at differential premotor cortex involvement

    NARCIS (Netherlands)

    Potgieser, A. R. E.; de Jong, B. M.

    2011-01-01

    Right-handed people generally write with their right hand. Language expressed in script is thus performed with the hand also preferred for skilled motor tasks. This may suggest an efficient functional interaction between the language area of Broca and the adjacent ventral premotor cortex (PMv) in th

  15. Low-frequency transcranial magnetic stimulation over left dorsal premotor cortex improves the dynamic control of visuospatially cued actions

    DEFF Research Database (Denmark)

    Ward, Nick S; Bestmann, Sven; Hartwigsen, Gesa

    2010-01-01

    responses in invalidly cued trials. After real rTMS, task-related activity of the stimulated left rPMd showed increased task-related coupling with activity in ipsilateral SMG and the adjacent anterior intraparietal area (AIP). Individuals who showed a stronger increase in left-hemispheric premotor-parietal...

  16. Trajectory and terminal distribution of single centrifugal axons from olfactory cortical areas in the rat olfactory bulb.

    Science.gov (United States)

    Matsutani, S

    2010-08-11

    The olfactory bulb receives a large number of centrifugal fibers whose functions remain unclear. To gain insight into the function of the bulbar centrifugal system, the morphology of individual centrifugal axons from olfactory cortical areas was examined in detail. An anterograde tracer, Phaseolus vulgaris leucoagglutinin, was injected into rat olfactory cortical areas, including the pars lateralis of the anterior olfactory nucleus (lAON) and the anterior part of the piriform cortex (aPC). Reconstruction from serial sections revealed that the extrabulbar segments of centrifugal axons from the lAON and those from the aPC had distinct trajectories: the former tended to innervate the pars externa of the AON before entering the olfactory bulb, while the latter had extrabulbar collaterals that extended to a variety of targets. In contrast to the extrabulbar segments, no clear differences were found between the intrabulbar segments of axons from the lAON and from the aPC. The intrabulbar segments of centrifugal axons were mainly found in the granule cell layer but a few axons extended into the external plexiform and glomerular layer. Approximately 40% of centrifugal axons innervated both the medial and lateral aspects of the olfactory bulb. The number of boutons found on single intrabulbar segments was typically less than 1000. Boutons tended to aggregate and form complex terminal tufts with short axonal branches. Terminal tufts, no more than 10 in single axons from ipsilateral cortical areas, were localized to the granule cell layer with varying intervals; some tufts formed patchy clusters and others were scattered over areas that extended for a few millimeters. The patchy, widespread distribution of terminals suggests that the centrifugal axons are able to couple the activity of specific subsets of bulbar neurons even when the subsets are spatially separated.

  17. Motor-cortical interaction in Gilles de la Tourette syndrome.

    Directory of Open Access Journals (Sweden)

    Stephanie Franzkowiak

    Full Text Available BACKGROUND: In Gilles de la Tourette syndrome (GTS increased activation of the primary motor cortex (M1 before and during movement execution followed by increased inhibition after movement termination was reported. The present study aimed at investigating, whether this activation pattern is due to altered functional interaction between motor cortical areas. METHODOLOGY/PRINCIPAL FINDINGS: 10 GTS-patients and 10 control subjects performed a self-paced finger movement task while neuromagnetic brain activity was recorded using Magnetoencephalography (MEG. Cerebro-cerebral coherence as a measure of functional interaction was calculated. During movement preparation and execution coherence between contralateral M1 and supplementary motor area (SMA was significantly increased at beta-frequency in GTS-patients. After movement termination no significant differences between groups were evident. CONCLUSIONS/SIGNIFICANCE: The present data suggest that increased M1 activation in GTS-patients might be due to increased functional interaction between SMA and M1 most likely reflecting a pathophysiological marker of GTS. The data extend previous findings of motor-cortical alterations in GTS by showing that local activation changes are associated with alterations of functional networks between premotor and primary motor areas. Interestingly enough, alterations were evident during preparation and execution of voluntary movements, which implies a general theme of increased motor-cortical interaction in GTS.

  18. Does Degree of Gyrification Underlie the Phenotypic and Genetic Associations between Cortical Surface Area and Cognitive Ability?

    Science.gov (United States)

    Docherty, Anna R.; Hagler, Donald J.; Panizzon, Matthew S.; Neale, Michael C.; Eyler, Lisa T.; Fennema-Notestine, Christine; Franz, Carol E.; Jak, Amy; Lyons, Michael J.; Rinker, Daniel A.; Thompson, Wesley K.; Tsuang, Ming T.; Dale, Anders M.; Kremen, William S.

    2015-01-01

    The phenotypic and genetic relationship between global cortical size and general cognitive ability (GCA) appears to be driven by surface area (SA) and not cortical thickness (CT). Gyrification (cortical folding) is an important property of the cortex that helps to increase SA within a finite space, and may also improve connectivity by reducing distance between regions. Hence, gyrification may be what underlies the SA-GCA relationship. In previous phenotypic studies, a 3-dimensional gyrification index (3DGI) has been positively associated with cognitive ability and negatively associated with mild cognitive impairment, Alzheimer’s disease, and psychiatric disorders affecting cognition. However, the differential genetic associations of 3DGI and SA with GCA are still unclear. We examined the heritability of 3DGI, and the phenotypic, genetic, and environmental associations of 3DGI with SA and GCA in a large sample of adult male twins (N = 512). Nearly 85% of the variance in 3DGI was due to genes, and 3DGI had a strong phenotypic and genetic association with SA. Both 3DGI and total SA had positive phenotypic correlations with GCA. However, the SA-GCA correlation remained significant after controlling for 3DGI, but not the other way around. There was also significant genetic covariance between SA and GCA, but not between 3DGI and GCA. Thus, despite the phenotypic and genetic associations between 3DGI and SA, our results do not support the hypothesis that gyrification underlies the association between SA and GCA. PMID:25433211

  19. Functional magnetic resonance imaging suggests automatization of the cortical response to inspiratory threshold loading in humans.

    Science.gov (United States)

    Raux, Mathieu; Tyvaert, Louise; Ferreira, Michael; Kindler, Félix; Bardinet, Eric; Karachi, Carine; Morelot-Panzini, Capucine; Gotman, Jean; Pike, G Bruce; Koski, Lisa; Similowski, Thomas

    2013-12-01

    Inspiratory threshold loading (ITL) induces cortical activation. It is sustained over time and is resistant to distraction, suggesting automaticity. We hypothesized that ITL-induced changes in cerebral activation may differ between single-breath ITL and continuous ITL, with differences resembling those observed after cortical automatization of motor tasks. We analyzed the brain blood oxygen level dependent (BOLD) signal of 11 naive healthy volunteers during 5 min of random, single-breath ITL and 5 min of continuous ITL. Single-breath ITL increased BOLD in many areas (premotor cortices, bilateral insula, cerebellum, reticular formation of the lateral mesencephalon) and decreased BOLD in regions co-localizing with the default mode network. Continuous ITL induced signal changes in a limited number of areas (supplementary motor area). These differences are comparable to those observed before and after overlearning of motor tasks. We conclude that the respiratory-related cortical activation observed in response to ITL is likely due to automated, attention-independent mechanisms. Also, ITL activates cortical circuits right from the first breath.

  20. Association of common genetic variants in GPCPD1 with scaling of visual cortical surface area in humans.

    Science.gov (United States)

    Bakken, Trygve E; Roddey, J Cooper; Djurovic, Srdjan; Akshoomoff, Natacha; Amaral, David G; Bloss, Cinnamon S; Casey, B J; Chang, Linda; Ernst, Thomas M; Gruen, Jeffrey R; Jernigan, Terry L; Kaufmann, Walter E; Kenet, Tal; Kennedy, David N; Kuperman, Joshua M; Murray, Sarah S; Sowell, Elizabeth R; Rimol, Lars M; Mattingsdal, Morten; Melle, Ingrid; Agartz, Ingrid; Andreassen, Ole A; Schork, Nicholas J; Dale, Anders M; Weiner, Michael; Aisen, Paul; Petersen, Ronald; Jack, Clifford R; Jagust, William; Trojanowki, John Q; Toga, Arthur W; Beckett, Laurel; Green, Robert C; Saykin, Andrew J; Morris, John; Liu, Enchi; Montine, Tom; Gamst, Anthony; Thomas, Ronald G; Donohue, Michael; Walter, Sarah; Gessert, Devon; Sather, Tamie; Harvey, Danielle; Kornak, John; Dale, Anders; Bernstein, Matthew; Felmlee, Joel; Fox, Nick; Thompson, Paul; Schuff, Norbert; Alexander, Gene; DeCarli, Charles; Bandy, Dan; Koeppe, Robert A; Foster, Norm; Reiman, Eric M; Chen, Kewei; Mathis, Chet; Cairns, Nigel J; Taylor-Reinwald, Lisa; Trojanowki, J Q; Shaw, Les; Lee, Virginia M Y; Korecka, Magdalena; Crawford, Karen; Neu, Scott; Foroud, Tatiana M; Potkin, Steven; Shen, Li; Kachaturian, Zaven; Frank, Richard; Snyder, Peter J; Molchan, Susan; Kaye, Jeffrey; Quinn, Joseph; Lind, Betty; Dolen, Sara; Schneider, Lon S; Pawluczyk, Sonia; Spann, Bryan M; Brewer, James; Vanderswag, Helen; Heidebrink, Judith L; Lord, Joanne L; Johnson, Kris; Doody, Rachelle S; Villanueva-Meyer, Javier; Chowdhury, Munir; Stern, Yaakov; Honig, Lawrence S; Bell, Karen L; Morris, John C; Ances, Beau; Carroll, Maria; Leon, Sue; Mintun, Mark A; Schneider, Stacy; Marson, Daniel; Griffith, Randall; Clark, David; Grossman, Hillel; Mitsis, Effie; Romirowsky, Aliza; deToledo-Morrell, Leyla; Shah, Raj C; Duara, Ranjan; Varon, Daniel; Roberts, Peggy; Albert, Marilyn; Onyike, Chiadi; Kielb, Stephanie; Rusinek, Henry; de Leon, Mony J; Glodzik, Lidia; De Santi, Susan; Doraiswamy, P Murali; Petrella, Jeffrey R; Coleman, R Edward; Arnold, Steven E; Karlawish, Jason H; Wolk, David; Smith, Charles D; Jicha, Greg; Hardy, Peter; Lopez, Oscar L; Oakley, MaryAnn; Simpson, Donna M; Porsteinsson, Anton P; Goldstein, Bonnie S; Martin, Kim; Makino, Kelly M; Ismail, M Saleem; Brand, Connie; Mulnard, Ruth A; Thai, Gaby; Mc-Adams-Ortiz, Catherine; Womack, Kyle; Mathews, Dana; Quiceno, Mary; Diaz-Arrastia, Ramon; King, Richard; Weiner, Myron; Martin-Cook, Kristen; DeVous, Michael; Levey, Allan I; Lah, James J; Cellar, Janet S; Burns, Jeffrey M; Anderson, Heather S; Swerdlow, Russell H; Apostolova, Liana; Lu, Po H; Bartzokis, George; Silverman, Daniel H S; Graff-Radford, Neill R; Parfitt, Francine; Johnson, Heather; Farlow, Martin R; Hake, Ann Marie; Matthews, Brandy R; Herring, Scott; van Dyck, Christopher H; Carson, Richard E; MacAvoy, Martha G; Chertkow, Howard; Bergman, Howard; Hosein, Chris; Black, Sandra; Stefanovic, Bojana; Caldwell, Curtis; Ging-Yuek; Hsiung, Robin; Feldman, Howard; Mudge, Benita; Assaly, Michele; Kertesz, Andrew; Rogers, John; Trost, Dick; Bernick, Charles; Munic, Donna; Kerwin, Diana; Mesulam, Marek-Marsel; Lipowski, Kristina; Wu, Chuang-Kuo; Johnson, Nancy; Sadowsky, Carl; Martinez, Walter; Villena, Teresa; Turner, Raymond Scott; Johnson, Kathleen; Reynolds, Brigid; Sperling, Reisa A; Johnson, Keith A; Marshall, Gad; Frey, Meghan; Yesavage, Jerome; Taylor, Joy L; Lane, Barton; Rosen, Allyson; Tinklenberg, Jared; Sabbagh, Marwan; Belden, Christine; Jacobson, Sandra; Kowall, Neil; Killiany, Ronald; Budson, Andrew E; Norbash, Alexander; Johnson, Patricia Lynn; Obisesan, Thomas O; Wolday, Saba; Bwayo, Salome K; Lerner, Alan; Hudson, Leon; Ogrocki, Paula; Fletcher, Evan; Carmichael, Owen; Olichney, John; Kittur, Smita; Borrie, Michael; Lee, T-Y; Bartha, Rob; Johnson, Sterling; Asthana, Sanjay; Carlsson, Cynthia M; Potkin, Steven G; Preda, Adrian; Nguyen, Dana; Tariot, Pierre; Fleisher, Adam; Reeder, Stephanie; Bates, Vernice; Capote, Horacio; Rainka, Michelle; Scharre, Douglas W; Kataki, Maria; Zimmerman, Earl A; Celmins, Dzintra; Brown, Alice D; Pearlson, Godfrey D; Blank, Karen; Anderson, Karen; Santulli, Robert B; Schwartz, Eben S; Sink, Kaycee M; Williamson, Jeff D; Garg, Pradeep; Watkins, Franklin; Ott, Brian R; Querfurth, Henry; Tremont, Geoffrey; Salloway, Stephen; Malloy, Paul; Correia, Stephen; Rosen, Howard J; Miller, Bruce L; Mintzer, Jacobo; Longmire, Crystal Flynn; Spicer, Kenneth; Finger, Elizabether; Rachinsky, Irina; Drost, Dick; Jernigan, Terry; McCabe, Connor; Grant, Ellen; Ernst, Thomas; Kuperman, Josh; Chung, Yoon; Murray, Sarah; Bloss, Cinnamon; Darst, Burcu; Pritchett, Lexi; Saito, Ashley; Amaral, David; DiNino, Mishaela; Eyngorina, Bella; Sowell, Elizabeth; Houston, Suzanne; Soderberg, Lindsay; Kaufmann, Walter; van Zijl, Peter; Rizzo-Busack, Hilda; Javid, Mohsin; Mehta, Natasha; Ruberry, Erika; Powers, Alisa; Rosen, Bruce; Gebhard, Nitzah; Manigan, Holly; Frazier, Jean; Kennedy, David; Yakutis, Lauren; Hill, Michael; Gruen, Jeffrey; Bosson-Heenan, Joan; Carlson, Heatherly

    2012-03-06

    Visual cortical surface area varies two- to threefold between human individuals, is highly heritable, and has been correlated with visual acuity and visual perception. However, it is still largely unknown what specific genetic and environmental factors contribute to normal variation in the area of visual cortex. To identify SNPs associated with the proportional surface area of visual cortex, we performed a genome-wide association study followed by replication in two independent cohorts. We identified one SNP (rs6116869) that replicated in both cohorts and had genome-wide significant association (P(combined) = 3.2 × 10(-8)). Furthermore, a metaanalysis of imputed SNPs in this genomic region identified a more significantly associated SNP (rs238295; P = 6.5 × 10(-9)) that was in strong linkage disequilibrium with rs6116869. These SNPs are located within 4 kb of the 5' UTR of GPCPD1, glycerophosphocholine phosphodiesterase GDE1 homolog (Saccharomyces cerevisiae), which in humans, is more highly expressed in occipital cortex compared with the remainder of cortex than 99.9% of genes genome-wide. Based on these findings, we conclude that this common genetic variation contributes to the proportional area of human visual cortex. We suggest that identifying genes that contribute to normal cortical architecture provides a first step to understanding genetic mechanisms that underlie visual perception.

  1. Cortical afferents of visual area MT in the Cebus monkey: possible homologies between New and Old World monkeys.

    Science.gov (United States)

    Rosa, M G; Soares, J G; Fiorani, M; Gattass, R

    1993-01-01

    Cortical projections to the middle temporal (MT) visual area were studied by injecting the retrogradely transported fluorescent tracer Fast Blue into MT in adult New World monkeys (Cebus apella). Injection sites were selected based on electrophysiological recordings, and covered eccentricities from 2-70 deg, in both the upper and lower visual fields. The position and laminar distribution of labeled cell bodies were correlated with myeloarchitectonic boundaries and displayed in flat reconstructions of the neocortex. Topographically organized projections were found to arise mainly from the primary, second, third, and fourth visual areas (V1, V2, V3, and V4). Coarsely topographic patterns were observed in transitional V4 (V4t), in the parieto-occipital and parieto-occipital medial areas (PO and POm), and in the temporal ventral posterior area (TVP). In addition, widespread or nontopographic label was found in visual areas of the superior temporal sulcus (medial superior temporal, MST, and fundus of superior temporal, FST), annectent gyrus (dorsointermediate area, DI; and dorsomedial area, DM), intraparietal sulcus (lateral intraparietal, LIP; posterior intraparietal, PIP; and ventral intraparietal, VIP), and in the frontal eye field (FEF). Label in PO, POm, and PIP was found only after injections in the representation of the peripheral visual field (> 10 deg), and label in V4 and FST was more extensive after injections in the central representation. The projections from V1 and V2 originated predominantly from neurons in supragranular layers, whereas those from V3, V4t, DM, DI, POm, and FEF consisted of intermixed patches with either supragranular or infragranular predominance. All of the other projections were predominantly infragranular. Invasion of area MST by the injection site led to the labeling of further pathways, including substantial projections from the dorsal prelunate area (DP) and from an ensemble of areas located along the medial wall of the hemisphere

  2. Laterality of movement-related activity reflects transformation of coordinates in ventral premotor cortex and primary motor cortex of monkeys.

    Science.gov (United States)

    Kurata, Kiyoshi

    2007-10-01

    The ventral premotor cortex (PMv) and the primary motor cortex (MI) of monkeys participate in various sensorimotor integrations, such as the transformation of coordinates from visual to motor space, because the areas contain movement-related neuronal activity reflecting either visual or motor space. In addition to relationship to visual and motor space, laterality of the activity could indicate stages in the visuomotor transformation. Thus we examined laterality and relationship to visual and motor space of movement-related neuronal activity in the PMv and MI of monkeys performing a fast-reaching task with the left or right arm, toward targets with visual and motor coordinates that had been dissociated by shift prisms. We determined laterality of each activity quantitatively and classified it into four types: activity that consistently depended on target locations in either head-centered visual coordinates (V-type) or motor coordinates (M-type) and those that had either differential or nondifferential activity for both coordinates (B- and N-types). A majority of M-type neurons in the areas had preferences for reaching movements with the arm contralateral to the hemisphere where neuronal activity was recorded. In contrast, most of the V-type neurons were recorded in the PMv and exhibited less laterality than the M-type. The B- and N-types were recorded in the PMv and MI and exhibited intermediate properties between the V- and M-types when laterality and correlations to visual and motor space of them were jointly examined. These results suggest that the cortical motor areas contribute to the transformation of coordinates to generate final motor commands.

  3. Multisensory and modality specific processing of visual speech in different regions of the premotor cortex.

    Science.gov (United States)

    Callan, Daniel E; Jones, Jeffery A; Callan, Akiko

    2014-01-01

    Behavioral and neuroimaging studies have demonstrated that brain regions involved with speech production also support speech perception, especially under degraded conditions. The premotor cortex (PMC) has been shown to be active during both observation and execution of action ("Mirror System" properties), and may facilitate speech perception by mapping unimodal and multimodal sensory features onto articulatory speech gestures. For this functional magnetic resonance imaging (fMRI) study, participants identified vowels produced by a speaker in audio-visual (saw the speaker's articulating face and heard her voice), visual only (only saw the speaker's articulating face), and audio only (only heard the speaker's voice) conditions with varying audio signal-to-noise ratios in order to determine the regions of the PMC involved with multisensory and modality specific processing of visual speech gestures. The task was designed so that identification could be made with a high level of accuracy from visual only stimuli to control for task difficulty and differences in intelligibility. The results of the functional magnetic resonance imaging (fMRI) analysis for visual only and audio-visual conditions showed overlapping activity in inferior frontal gyrus and PMC. The left ventral inferior premotor cortex (PMvi) showed properties of multimodal (audio-visual) enhancement with a degraded auditory signal. The left inferior parietal lobule and right cerebellum also showed these properties. The left ventral superior and dorsal premotor cortex (PMvs/PMd) did not show this multisensory enhancement effect, but there was greater activity for the visual only over audio-visual conditions in these areas. The results suggest that the inferior regions of the ventral premotor cortex are involved with integrating multisensory information, whereas, more superior and dorsal regions of the PMC are involved with mapping unimodal (in this case visual) sensory features of the speech signal with

  4. Cross-Modal Plasticity Results in Increased Inhibition in Primary Auditory Cortical Areas

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    Yu-Ting Mao

    2013-01-01

    Full Text Available Loss of sensory input from peripheral organ damage, sensory deprivation, or brain damage can result in adaptive or maladaptive changes in sensory cortex. In previous research, we found that auditory cortical tuning and tonotopy were impaired by cross-modal invasion of visual inputs. Sensory deprivation is typically associated with a loss of inhibition. To determine whether inhibitory plasticity is responsible for this process, we measured pre- and postsynaptic changes in inhibitory connectivity in ferret auditory cortex (AC after cross-modal plasticity. We found that blocking GABAA receptors increased responsiveness and broadened sound frequency tuning in the cross-modal group more than in the normal group. Furthermore, expression levels of glutamic acid decarboxylase (GAD protein were increased in the cross-modal group. We also found that blocking inhibition unmasked visual responses of some auditory neurons in cross-modal AC. Overall, our data suggest a role for increased inhibition in reducing the effectiveness of the abnormal visual inputs and argue that decreased inhibition is not responsible for compromised auditory cortical function after cross-modal invasion. Our findings imply that inhibitory plasticity may play a role in reorganizing sensory cortex after cross-modal invasion, suggesting clinical strategies for recovery after brain injury or sensory deprivation.

  5. Reduced density of glutamine synthetase immunoreactive astrocytes in different cortical areas in major depression but not in bipolar I disorder.

    Science.gov (United States)

    Bernstein, Hans-Gert; Meyer-Lotz, Gabriela; Dobrowolny, Henrik; Bannier, Jana; Steiner, Johann; Walter, Martin; Bogerts, Bernhard

    2015-01-01

    There is increasing evidence for disturbances within the glutamate system in patients with affective disorders, which involve disruptions of the glutamate-glutamine-cycle. The mainly astroglia-located enzyme glutamine synthetase (GS) catalyzes the ATP-dependent condensation of ammonia and glutamate to form glutamine, thus playing a central role in glutamate and glutamine homoeostasis. However, GS is also expressed in numerous oligodendrocytes (OLs), another class of glial cells implicated in mood disorder pathology. To learn more about the role of glia-associated GS in mental illnesses, we decided to find out if numerical densities of glial cells immunostained for the enzyme protein differ between subjects with major depressive disorder, bipolar disorder (BD), and psychically healthy control cases. Counting of GS expressing astrocytes (ACs) and OLs in eight cortical and two subcortical brain regions of subjects with mood disorder (N = 14), BD (N = 15), and controls (N = 16) revealed that in major depression the densities of ACs were significantly reduced in some cortical but not subcortical gray matter areas, whereas no changes were found for OLs. In BD no alterations of GS-immunoreactive glia were found. From our findings we conclude that (1) GS expressing ACs are prominently involved in glutamate-related disturbances in major depression, but not in BD and (2) GS expressing OLs, though being present in significant numbers in prefrontal cortical areas, play a minor (if any) role in mood disorder pathology. The latter assumption is supported by findings of others showing that - at least in the mouse brain cortex - GS immunoreactive oligodendroglial cells are unable to contribute to the glutamate-glutamine-cycle due to the complete lack of amino acid transporters (Takasaki et al., 2010).

  6. Feedback from visual cortical area 7 to areas 17 and 18 in cats: How neural web is woven during feedback.

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    Yang, X; Ding, H; Lu, J

    2016-01-15

    To investigate the feedback effect from area 7 to areas 17 and 18, intrinsic signal optical imaging combined with pharmacological, morphological methods and functional magnetic resonance imaging (fMRI) was employed. A spatial frequency-dependent decrease in response amplitude of orientation maps was observed in areas 17 and 18 when area 7 was inactivated by a local injection of GABA, or by a lesion induced by liquid nitrogen freezing. The pattern of orientation maps of areas 17 and 18 after the inactivation of area 7, if they were not totally blurred, paralleled the normal one. In morphological experiments, after one point at the shallow layers within the center of the cat's orientation column of area 17 was injected electrophoretically with HRP (horseradish peroxidase), three sequential patches in layers 1, 2 and 3 of area 7 were observed. Employing fMRI it was found that area 7 feedbacks mainly to areas 17 and 18 on ipsilateral hemisphere. Therefore, our conclusions are: (1) feedback from area 7 to areas 17 and 18 is spatial frequency modulated; (2) feedback from area 7 to areas 17 and 18 occurs mainly ipsilaterally; (3) histological feedback pattern from area 7 to area 17 is weblike.

  7. Modulation of specific sensory cortical areas by segregated basal forebrain cholinergic neurons demonstrated by neuronal tracing and optogenetic stimulation in mice

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    Irene eChaves-Coira

    2016-04-01

    Full Text Available Neocortical cholinergic activity plays a fundamental role in sensory processing and cognitive functions. Previous results have suggested a refined anatomical and functional topographical organization of basal forebrain (BF projections that may control cortical sensory processing in a specific manner. We have used retrograde anatomical procedures to demonstrate the existence of specific neuronal groups in the BF involved in the control of specific sensory cortices. Fluoro-gold and Fast Blue fluorescent retrograde tracers were deposited into the primary somatosensory (S1 and primary auditory (A1 cortices in mice. Our results revealed that the BF is a heterogeneous area in which neurons projecting to different cortical areas are segregated into different neuronal groups. Most of the neurons located in the horizontal limb of the diagonal band of Broca (HDB projected to the S1 cortex, indicating that this area is specialized in the sensory processing of tactile stimuli. However, the nucleus basalis magnocellularis (B nucleus shows a similar number of cells projecting to the S1 as to the A1 cortices. In addition, we analyzed the cholinergic effects on the S1 and A1 cortical sensory responses by optogenetic stimulation of the BF neurons in urethane-anesthetized transgenic mice. We used transgenic mice expressing the light-activated cation channel, channelrhodopsin-2, tagged with a fluorescent protein (ChR2-YFP under the control of the choline-acetyl transferase promoter (ChAT. Cortical evoked potentials were induced by whisker deflections or by auditory clicks. According to the anatomical results, optogenetic HDB stimulation induced more extensive facilitation of tactile evoked potentials in S1 than auditory evoked potentials in A1, while optogenetic stimulation of the B nucleus facilitated either tactile or auditory evoked potentials equally. Consequently, our results suggest that cholinergic projections to the cortex are organized into segregated

  8. Modulation of Specific Sensory Cortical Areas by Segregated Basal Forebrain Cholinergic Neurons Demonstrated by Neuronal Tracing and Optogenetic Stimulation in Mice

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    Chaves-Coira, Irene; Barros-Zulaica, Natali; Rodrigo-Angulo, Margarita; Núñez, Ángel

    2016-01-01

    Neocortical cholinergic activity plays a fundamental role in sensory processing and cognitive functions. Previous results have suggested a refined anatomical and functional topographical organization of basal forebrain (BF) projections that may control cortical sensory processing in a specific manner. We have used retrograde anatomical procedures to demonstrate the existence of specific neuronal groups in the BF involved in the control of specific sensory cortices. Fluoro-Gold (FlGo) and Fast Blue (FB) fluorescent retrograde tracers were deposited into the primary somatosensory (S1) and primary auditory (A1) cortices in mice. Our results revealed that the BF is a heterogeneous area in which neurons projecting to different cortical areas are segregated into different neuronal groups. Most of the neurons located in the horizontal limb of the diagonal band of Broca (HDB) projected to the S1 cortex, indicating that this area is specialized in the sensory processing of tactile stimuli. However, the nucleus basalis magnocellularis (B) nucleus shows a similar number of cells projecting to the S1 as to the A1 cortices. In addition, we analyzed the cholinergic effects on the S1 and A1 cortical sensory responses by optogenetic stimulation of the BF neurons in urethane-anesthetized transgenic mice. We used transgenic mice expressing the light-activated cation channel, channelrhodopsin-2, tagged with a fluorescent protein (ChR2-YFP) under the control of the choline-acetyl transferase promoter (ChAT). Cortical evoked potentials were induced by whisker deflections or by auditory clicks. According to the anatomical results, optogenetic HDB stimulation induced more extensive facilitation of tactile evoked potentials in S1 than auditory evoked potentials in A1, while optogenetic stimulation of the B nucleus facilitated either tactile or auditory evoked potentials equally. Consequently, our results suggest that cholinergic projections to the cortex are organized into segregated

  9. Distinct Neural Activities in Premotor Cortex during Natural Vocal Behaviors in a New World Primate, the Common Marmoset (Callithrix jacchus).

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    Roy, Sabyasachi; Zhao, Lingyun; Wang, Xiaoqin

    2016-11-30

    Although evidence from human studies has long indicated the crucial role of the frontal cortex in speech production, it has remained uncertain whether the frontal cortex in nonhuman primates plays a similar role in vocal communication. Previous studies of prefrontal and premotor cortices of macaque monkeys have found neural signals associated with cue- and reward-conditioned vocal production, but not with self-initiated or spontaneous vocalizations (Coudé et al., 2011; Hage and Nieder, 2013), which casts doubt on the role of the frontal cortex of the Old World monkeys in vocal communication. A recent study of marmoset frontal cortex observed modulated neural activities associated with self-initiated vocal production (Miller et al., 2015), but it did not delineate whether these neural activities were specifically attributed to vocal production or if they may result from other nonvocal motor activity such as orofacial motor movement. In the present study, we attempted to resolve these issues and examined single neuron activities in premotor cortex during natural vocal exchanges in the common marmoset (Callithrix jacchus), a highly vocal New World primate. Neural activation and suppression were observed both before and during self-initiated vocal production. Furthermore, by comparing neural activities between self-initiated vocal production and nonvocal orofacial motor movement, we identified a subpopulation of neurons in marmoset premotor cortex that was activated or suppressed by vocal production, but not by orofacial movement. These findings provide clear evidence of the premotor cortex's involvement in self-initiated vocal production in natural vocal behaviors of a New World primate.

  10. The threshold of cortical electrical stimulation for mapping sensory and motor functional areas.

    Science.gov (United States)

    Guojun, Zhang; Duanyu, Ni; Fu, Paul; Lixin, Cai; Tao, Yu; Wei, Du; Liang, Qiao; Zhiwei, Ren

    2014-02-01

    This study aimed to investigate the threshold of cortical electrical stimulation (CES) for functional brain mapping during surgery for the treatment of rolandic epilepsy. A total of 21 patients with rolandic epilepsy who underwent surgical treatment at the Beijing Institute of Functional Neurosurgery between October 2006 and March 2008 were included in this study. Their clinical data were retrospectively collected and analyzed. The thresholds of CES for motor response, sensory response, and after discharge production along with other threshold-related factors were investigated. The thresholds (mean ± standard deviation) for motor response, sensory response, and after discharge production were 3.48 ± 0.87, 3.86 ± 1.31, and 4.84 ± 1.38 mA, respectively. The threshold for after discharge production was significantly higher than those of both the motor and sensory response (both pthreshold of after discharge production and disease duration. Using the CES parameters at a stimulation frequency of 50 Hz and a pulse width of 0.2 ms, the threshold of sensory and motor responses were similar, and the threshold of after discharge production was higher than that of sensory and motor response. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Activation of cortical areas in music execution and imagining: a high-resolution EEG study.

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    Kristeva, Rumyana; Chakarov, Vihren; Schulte-Mönting, Jürgen; Spreer, Joachim

    2003-11-01

    Neuroimaging studies have shown that execution of a musical sequence on an instrument activates bilateral frontal opercular regions, in addition to bilateral sensorimotor and supplementary motor areas. During imagining activation of the same areas without primary sensorimotor areas was shown. We recorded EEG from 58 scalp positions to investigate the temporal sequence and the time course of activation of these areas while violin players prepared to execute, executed, prepared to imagine, or imagined a musical sequence on a violin. During the preparation for the sequence in three of seven musicians investigated the bilateral frontal opercular regions became active earlier than the motor areas and in one of them simultaneously with the motor areas. In two of the musicians a rather variable pattern of activation was observed. The frontal opercular regions were also strongly involved throughout the period of music execution or imagining. The supplementary motor area was involved in both preparation for the sequence and during execution and imagining of the sequence. The left primary sensorimotor area was involved in the preparation and termination of the musical sequence for both execution and imagining. The right sensorimotor area was strongly involved in the preparation for and during the execution of the sequence. We conclude that the bilateral frontal opercular regions are crucial in both preparation for and during music execution and imagining. They may have "mirror neurone" properties that underlie observation or imagining of one's own performance. The motor areas are differentially activated during the preparation and execution or imagining the sequence.

  12. Structural asymmetry of the human cerebral cortex: Regional and between-subject variability of surface area, cortical thickness, and local gyrification.

    Science.gov (United States)

    Chiarello, Christine; Vazquez, David; Felton, Adam; McDowell, Alessandra

    2016-12-01

    Structural asymmetry varies across individuals, brain regions, and metrics of cortical organization. The current study investigated regional differences in asymmetry of cortical surface area, thickness, and local gyrification, and the extent of between-subject variability in these metrics, in a sample of healthy young adults (N=200). Between-subject variability in cortical structure may provide a means to assess the extent of biological flexibility or constraint of brain regions, and we explored the potential influence of this variability on the phenotypic expression of structural asymmetry. The findings demonstrate that structural asymmetries are nearly ubiquitous across the cortex, with differing regional organization for the three cortical metrics. This implies that there are multiple, only partially overlapping, maps of structural asymmetry. The results further indicate that the degree of asymmetry of a brain region can be predicted by the extent of the region's between-subject variability. These findings provide evidence that reduced biological constraint promotes the expression of strong structural asymmetry.

  13. Cortical Motor Circuits after Piano Training in Adulthood: Neurophysiologic Evidence.

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    Elise Houdayer

    Full Text Available The neuronal mechanisms involved in brain plasticity after skilled motor learning are not completely understood. We aimed to study the short-term effects of keyboard training in music-naive subjects on the motor/premotor cortex activity and interhemispheric interactions, using electroencephalography and transcranial magnetic stimulation (TMS. Twelve subjects (experimental group underwent, before and after a two week-piano training: (1 hand-motor function tests: Jamar, grip and nine-hole peg tests; (2 electroencephalography, evaluating the mu rhythm task-related desynchronization (TRD during keyboard performance; and (3 TMS, targeting bilateral abductor pollicis brevis (APB and abductor digiti minimi (ADM, to obtain duration and area of ipsilateral silent period (ISP during simultaneous tonic contraction of APB and ADM. Data were compared with 13 controls who underwent twice these measurements, in a two-week interval, without undergoing piano training. Every subject in the experimental group improved keyboard performance and left-hand nine-hole peg test scores. Pre-training, ISP durations were asymmetrical, left being longer than right. Post-training, right ISPAPB increased, leading to symmetrical ISPAPB. Mu TRD during motor performance became more focal and had a lesser amplitude than in pre-training, due to decreased activity over ventral premotor cortices. No such changes were evidenced in controls. We demonstrated that a 10-day piano-training was associated with balanced interhemispheric interactions both at rest and during motor activation. Piano training, in a short timeframe, may reshape local and inter-hemispheric motor cortical circuits.

  14. Cortical inputs to the middle temporal visual area in New World owl monkeys

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    Cerkevich CM

    2014-12-01

    Full Text Available Christina M Cerkevich,1 Christine E Collins,2 Jon H Kaas2 1Center for the Neural Basis of Cognition and Systems Neuroscience Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; 2Department of Psychology, Vanderbilt University, Nashville, TN, USA Abstract: We made eight retrograde tracer injections into the middle temporal visual area (MT of three New World owl monkeys (Aotus nancymaae. These injections were placed across the representation of the retina in MT to allow us to compare the locations of labeled cells in other areas in order to provide evidence for any retinotopic organization in those areas. Four regions projected to MT: 1 early visual areas, including V1, V2, V3, the dorsolateral visual area, and the dorsomedial visual area, provided topographically organized inputs to MT; 2 all areas in the MT complex (the middle temporal crescent, the middle superior temporal area, and the fundal areas of the superior temporal sulcus projected to MT. Somewhat variably across injections, neurons were labeled in other parts of the temporal lobe; 3 regions in the location of the medial visual area, the posterior parietal cortex, and the lateral sulcus provided other inputs to MT; 4 finally, projections from the frontal eye field, frontal visual field, and prefrontal cortex were also labeled by our injections. These results further establish the sources of input to MT, and provide direct evidence within and across cases for retinotopic patterns of projections from early visual areas to MT. Keywords: middle temporal area, visual cortex, parietal cortex

  15. Investigating the cortical regions involved in MEP modulation in tDCS

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    Ricardo eSalvador

    2015-10-01

    Full Text Available Transcranial magnetic stimulation (TMS is used in several studies to evaluate cortical excitability changes induced by transcranial direct current stimulation (tDCS of the primary motor cortex. Interpretation of these results, however, is hindered by the very different spatial distribution of the electric field (E-field induced by the two techniques and by the different target neurons that they might act upon. In this study we used the finite element method to calculate the E-field distribution induced by TMS and tDCS in a realistically shaped model of a human head. A model of a commercially available figure-8 coil was placed over a position above the identified hand knob (HK region. We also modelled two configurations of bipolar tDCS montages with one of the electrodes placed over the HK and a return electrode over the contralateral orbital region. The electrodes over the HK were either rectangular in shape, with an area of 35cm2 or cylindrical with an area of π cm2 (1 cm radius. To compare the E-field distribution in TMS and the two tDCS models, average values of the E-field’s magnitude as well as the polar and azimuthal angle were investigated in the HK region and premotor areas. The results show that both techniques induce fields with different magnitudes and directions in the HK: the field in tDCS is predominantly perpendicular to the cortical surface, contrary to what happens in TMS where the field is mostly parallel to it. In the premotor areas, the magnitude of the E-field induced in TMS was well below the accepted threshold for MEP generation, 100 V/m. In tDCS, the magnitude of the field in these areas was comparable to that induced at the HK with a significant component perpendicular to the cortical surface. These results indicate that tDCS and TMS target preferentially different neuronal structures at the HK. Besides, they show that premotor areas may play a role in the tDCS-induced after effects on motor cortex excitability.

  16. Neurochemical, morphologic, and laminar characterization of cortical projection neurons in the cingulate motor areas of the macaque monkey

    Science.gov (United States)

    Nimchinsky, E. A.; Hof, P. R.; Young, W. G.; Morrison, J. H.; Bloom, F. E. (Principal Investigator)

    1996-01-01

    The primate cingulate gyrus contains multiple cortical areas that can be distinguished by several neurochemical features, including the distribution of neurofilament protein-enriched pyramidal neurons. In addition, connectivity and functional properties indicate that there are multiple motor areas in the cortex lining the cingulate sulcus. These motor areas were targeted for analysis of potential interactions among regional specialization, connectivity, and cellular characteristics such as neurochemical profile and morphology. Specifically, intracortical injections of retrogradely transported dyes and intracellular injection were combined with immunocytochemistry to investigate neurons projecting from the cingulate motor areas to the putative forelimb region of the primary motor cortex, area M1. Two separate groups of neurons projecting to area M1 emanated from the cingulate sulcus, one anterior and one posterior, both of which furnished commissural and ipsilateral connections with area M1. The primary difference between the two populations was laminar origin, with the anterior projection originating largely in deep layers, and the posterior projection taking origin equally in superficial and deep layers. With regard to cellular morphology, the anterior projection exhibited more morphologic diversity than the posterior projection. Commissural projections from both anterior and posterior fields originated largely in layer VI. Neurofilament protein distribution was a reliable tool for localizing the two projections and for discriminating between them. Comparable proportions of the two sets of projection neurons contained neurofilament protein, although the density and distribution of the total population of neurofilament protein-enriched neurons was very different in the two subareas of origin. Within a projection, the participating neurons exhibited a high degree of morphologic heterogeneity, and no correlation was observed between somatodendritic morphology and

  17. Demonstration of a setup for chronic optogenetic stimulation and recording across cortical areas in non-human primates

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    Yazdan-Shahmorad, Azadeh; Diaz-Botia, Camilo; Hanson, Tim; Ledochowitsch, Peter; Maharabiz, Michel M.; Sabes, Philip N.

    2015-03-01

    Although several studies have shown the feasibility of using optogenetics in non-human primates (NHP), reliable largescale chronic interfaces have not yet been reported for such studies in NHP. Here we introduce a chronic setup that permits repeated, daily optogenetic stimulation and large-scale recording from the same sites in NHP cortex. The setup combines optogenetics with a transparent artificial dura (AD) and high-density micro-electrocorticography (μECoG). To obtain expression across large areas of cortex, we infused AAV5-CamKIIa-C1V1-EYFP viral vector using an infusion technique based on convection-enhanced delivery (CED) in primary somatosensory (S1) and motor (M1) cortices. By epifluorescent imaging through AD we were able to confirm high levels of expression covering about 110 mm2 of S1 and M1. We then incorporated a 192-channel μECoG array spanning 192 mm2 into the AD for simultaneous electrophysiological recording during optical stimulation. The array consists of patterned Pt-Au-Pt metal traces embedded in ~10 μm Parylene-C insulator. The parylene is sufficiently transparent to allow minimally attenuated optical access for optogenetic stimulation. The array was chronically implanted over the opsin-expressing areas in M1 and S1 for over two weeks. Optical stimulation was delivered via a fiber optic placed on the surface of the AD. With this setup, we recorded reliable evoked activity following light stimulation at several locations. Similar responses were recorded across tens of days, however a decline in the light-evoked signal amplitude was observed during this period due to the growth of dural tissue over the array. These results show the feasibility of a chronic interface for combined largescale optogenetic stimulation and cortical recordings across days.

  18. Prediction of the main cortical areas and connections involved in the tactile function of the visual cortex by network analysis.

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    Négyessy, László; Nepusz, Tamás; Kocsis, László; Bazsó, Fülöp

    2006-04-01

    We explored the cortical pathways from the primary somatosensory cortex to the primary visual cortex (V1) by analysing connectional data in the macaque monkey using graph-theoretical tools. Cluster analysis revealed the close relationship of the dorsal visual stream and the sensorimotor cortex. It was shown that prefrontal area 46 and parietal areas VIP and 7a occupy a central position between the different clusters in the visuo-tactile network. Among these structures all the shortest paths from primary somatosensory cortex (3a, 1 and 2) to V1 pass through VIP and then reach V1 via MT, V3 and PO. Comparison of the input and output fields suggested a larger specificity for the 3a/1-VIP-MT/V3-V1 pathways among the alternative routes. A reinforcement learning algorithm was used to evaluate the importance of the aforementioned pathways. The results suggest a higher role for V3 in relaying more direct sensorimotor information to V1. Analysing cliques, which identify areas with the strongest coupling in the network, supported the role of VIP, MT and V3 in visuo-tactile integration. These findings indicate that areas 3a, 1, VIP, MT and V3 play a major role in shaping the tactile information reaching V1 in both sighted and blind subjects. Our observations greatly support the findings of the experimental studies and provide a deeper insight into the network architecture underlying visuo-tactile integration in the primate cerebral cortex.

  19. Single neurons in M1 and premotor cortex directly reflect behavioral interference.

    Directory of Open Access Journals (Sweden)

    Neta Zach

    Full Text Available Some motor tasks, if learned together, interfere with each other's consolidation and subsequent retention, whereas other tasks do not. Interfering tasks are said to employ the same internal model whereas noninterfering tasks use different models. The division of function among internal models, as well as their possible neural substrates, are not well understood. To investigate these questions, we compared responses of single cells in the primary motor cortex and premotor cortex of primates to interfering and noninterfering tasks. The interfering tasks were visuomotor rotation followed by opposing visuomotor rotation. The noninterfering tasks were visuomotor rotation followed by an arbitrary association task. Learning two noninterfering tasks led to the simultaneous formation of neural activity typical of both tasks, at the level of single neurons. In contrast, and in accordance with behavioral results, after learning two interfering tasks, only the second task was successfully reflected in motor cortical single cell activity. These results support the hypothesis that the representational capacity of motor cortical cells is the basis of behavioral interference and division between internal models.

  20. Joint cross-correlation analysis reveals complex, time-dependent functional relationship between cortical neurons and arm electromyograms

    Science.gov (United States)

    Zhuang, Katie Z.; Lebedev, Mikhail A.

    2014-01-01

    Correlation between cortical activity and electromyographic (EMG) activity of limb muscles has long been a subject of neurophysiological studies, especially in terms of corticospinal connectivity. Interest in this issue has recently increased due to the development of brain-machine interfaces with output signals that mimic muscle force. For this study, three monkeys were implanted with multielectrode arrays in multiple cortical areas. One monkey performed self-timed touch pad presses, whereas the other two executed arm reaching movements. We analyzed the dynamic relationship between cortical neuronal activity and arm EMGs using a joint cross-correlation (JCC) analysis that evaluated trial-by-trial correlation as a function of time intervals within a trial. JCCs revealed transient correlations between the EMGs of multiple muscles and neural activity in motor, premotor and somatosensory cortical areas. Matching results were obtained using spike-triggered averages corrected by subtracting trial-shuffled data. Compared with spike-triggered averages, JCCs more readily revealed dynamic changes in cortico-EMG correlations. JCCs showed that correlation peaks often sharpened around movement times and broadened during delay intervals. Furthermore, JCC patterns were directionally selective for the arm-reaching task. We propose that such highly dynamic, task-dependent and distributed relationships between cortical activity and EMGs should be taken into consideration for future brain-machine interfaces that generate EMG-like signals. PMID:25210153

  1. Structural asymmetry of cortical visual areas is related to ocular dominance

    DEFF Research Database (Denmark)

    Jensen, Bettina H; Hougaard, Anders; Amin, Faisal M

    2015-01-01

    The grey matter of the human brain is asymmetrically distributed between the cerebral hemispheres. This asymmetry includes visual areas, but its relevance to visual function is not understood. Voxel-based morphometry is a well-established technique for localization and quantification of cerebral...... grey matter on the basis of MR images. This method has been used previously for interhemispheric comparison, but without examining the functional implications of the identified anatomical asymmetries of the visual system. The aim of the present study was to relate anatomical interhemispheric...... asymmetries to asymmetries of visual function. We examined grey matter asymmetries of visual areas in a large population (n=56) of ophthalmologically and neurologically healthy individuals. We used state-of-the-art 3 T MRI and voxel-based morphometry to relate the visual parameters, (a) ocular dominance, (b...

  2. Comparison of grey matter volume and thickness for analysing cortical changes in chronic schizophrenia: a matter of surface area, grey/white matter intensity contrast, and curvature.

    Science.gov (United States)

    Kong, Li; Herold, Christina J; Zöllner, Frank; Salat, David H; Lässer, Marc M; Schmid, Lena A; Fellhauer, Iven; Thomann, Philipp A; Essig, Marco; Schad, Lothar R; Erickson, Kirk I; Schröder, Johannes

    2015-02-28

    Grey matter volume and cortical thickness are the two most widely used measures for detecting grey matter morphometric changes in various diseases such as schizophrenia. However, these two measures only share partial overlapping regions in identifying morphometric changes. Few studies have investigated the contributions of the potential factors to the differences of grey matter volume and cortical thickness. To investigate this question, 3T magnetic resonance images from 22 patients with schizophrenia and 20 well-matched healthy controls were chosen for analyses. Grey matter volume and cortical thickness were measured by VBM and Freesurfer. Grey matter volume results were then rendered onto the surface template of Freesurfer to compare the differences from cortical thickness in anatomical locations. Discrepancy regions of the grey matter volume and thickness where grey matter volume significantly decreased but without corresponding evidence of cortical thinning involved the rostral middle frontal, precentral, lateral occipital and superior frontal gyri. Subsequent region-of-interest analysis demonstrated that changes in surface area, grey/white matter intensity contrast and curvature accounted for the discrepancies. Our results suggest that the differences between grey matter volume and thickness could be jointly driven by surface area, grey/white matter intensity contrast and curvature.

  3. Angiotensin converting enzyme in Alzheimer's disease increased activity in caudate nucleus and cortical areas.

    Science.gov (United States)

    Arregui, A; Perry, E K; Rossor, M; Tomlinson, B E

    1982-05-01

    The activity of the dipeptidyl carboxypeptidase, angiotensin converting enzyme, was assayed in several brain regions of patients dying with Alzheimer's disease and compared to that of appropriately age-matched controls. Enzyme activity was found to be elevated by 44% and 41% in the medial hippocampus and parahippocampal gyrus, respectively, and by 27% and 29% in the frontal cortex (area 10 of Brodman) and caudate nucleus, respectively, in Alzheimer's disease patients. Converting enzyme activity did not differ from controls in the nucleus accumbens, substantia nigra, temporal cortex, anterior or posterior hippocampus, amydgala, and septal nuclei.

  4. Estimation of the cortical functional connectivity with the multimodal integration of high-resolution EEG and fMRI data by directed transfer function.

    Science.gov (United States)

    Babiloni, F; Cincotti, F; Babiloni, C; Carducci, F; Mattia, D; Astolfi, L; Basilisco, A; Rossini, P M; Ding, L; Ni, Y; Cheng, J; Christine, K; Sweeney, J; He, B

    2005-01-01

    Nowadays, several types of brain imaging device are available to provide images of the functional activity of the cerebral cortex based on hemodynamic, metabolic, or electromagnetic measurements. However, static images of brain regions activated during particular tasks do not convey the information of how these regions communicate with each other. In this study, advanced methods for the estimation of cortical connectivity from combined high-resolution electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) data are presented. These methods include a subject's multicompartment head model (scalp, skull, dura mater, cortex) constructed from individual magnetic resonance images, multidipole source model, and regularized linear inverse source estimates of cortical current density. Determination of the priors in the resolution of the linear inverse problem was performed with the use of information from the hemodynamic responses of the cortical areas as revealed by block-designed (strength of activated voxels) fMRI. We estimate functional cortical connectivity by computing the directed transfer function (DTF) on the estimated cortical current density waveforms in regions of interest (ROIs) on the modeled cortical mantle. The proposed method was able to unveil the direction of the information flow between the cortical regions of interest, as it is directional in nature. Furthermore, this method allows to detect changes in the time course of information flow between cortical regions in different frequency bands. The reliability of these techniques was further demonstrated by elaboration of high-resolution EEG and fMRI signals collected during visually triggered finger movements in four healthy subjects. Connectivity patterns estimated for this task reveal an involvement of right parietal and bilateral premotor and prefrontal cortical areas. This cortical region involvement resembles that revealed in previous studies where visually triggered finger

  5. Distinct cortical areas for names of numbers and body parts independent of language and input modality.

    Science.gov (United States)

    Le Clec'H, G; Dehaene, S; Cohen, L; Mehler, J; Dupoux, E; Poline, J B; Lehéricy, S; van de Moortele, P F; Le Bihan, D

    2000-10-01

    Some models of word comprehension postulate that the processing of words presented in different modalities and languages ultimately converges toward common cerebral systems associated with semantic-level processing and that the localization of these systems may vary with the category of semantic knowledge being accessed. We used functional magnetic resonance imaging to investigate this hypothesis with two categories of words, numerals, and body parts, for which the existence of distinct category-specific areas is debated in neuropsychology. Across two experiments, one with a blocked design and the other with an event-related design, a reproducible set of left-hemispheric parietal and prefrontal areas showed greater activation during the manipulation of topographical knowledge about body parts and a right-hemispheric parietal network during the manipulation of numerical quantities. These results complement the existing neuropsychological and brain-imaging literature by suggesting that within the extensive network of bilateral parietal regions active during both number and body-part processing, a subset shows category-specific responses independent of the language and modality of presentation.

  6. Processing of Own Hand Visual Feedback during Object Grasping in Ventral Premotor Mirror Neurons.

    Science.gov (United States)

    Maranesi, Monica; Livi, Alessandro; Bonini, Luca

    2015-08-26

    Mirror neurons (MNs) discharge during action execution as well as during observation of others' actions. Our own actions are those that we have the opportunity to observe more frequently, but no study thus far to our knowledge has addressed the issue of whether, and to what extent, MNs can code own hand visual feedback (HVF) during object grasping. Here, we show that MNs of the ventral premotor area F5 of macaque monkeys are particularly sensitive to HVF relative to non-MNs simultaneously recorded in the same penetrations. Importantly, the HVF effect is more evident on MN activity during hand-object interaction than during the hand-shaping phase. Furthermore, the increase of MN activity induced by HVF and others' actions observed from a subjective perspective were positively correlated. These findings indicate that at least part of ventral premotor MNs can process the visual information coming from own hand interacting with objects, likely playing a role in self-action monitoring. We show that mirror neurons (MNs) of area F5 of the macaque, in addition to encoding others' observed actions, are particularly sensitive, relative to simultaneously recorded non-MNs, to the sight of the monkey's own hand during object grasping, likely playing a role in self-action monitoring. Copyright © 2015 the authors 0270-6474/15/3511824-06$15.00/0.

  7. Cortical Connectivity Maps Reveal Anatomically Distinct Areas in the Parietal Cortex of the Rat

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    Aaron eWilber

    2015-01-01

    Full Text Available A central feature of theories of spatial navigation involves the representation of spatial relationships between objects in complex environments. The parietal cortex has long been linked to the processing of spatial visual information and recent evidence from single unit recording in rodents suggests a role for this region in encoding egocentric and world-centered frames. The rat parietal cortex can be subdivided into up to four distinct rostral-caudal and medial-lateral regions, which includes a zone previously characterized as secondary visual cortex. At present, very little is known regarding the relative connectivity of these parietal subdivisions. Thus, we set out to map the connectivity of the entire anterior-posterior and medial-lateral span of this region. To do this we used anterograde and retrograde tracers in conjunction with open source neuronal segmentation and tracer detection tools to generate whole brain connectivity maps of parietal inputs and outputs. Our present results show that inputs to the parietal cortex varied significantly along the medial-lateral, but not the rostral-caudal axis. Specifically, retrosplenial connectivity is greater medially, but connectivity with visual cortex, though generally sparse, is more significant laterally. Finally, based on connection density, the connectivity between parietal cortex and hippocampus is indirect and likely achieved largely via dysgranular retrosplenial cortex. Thus, similar to primates, the parietal cortex of rats exhibits a difference in connectivity along the medial-lateral axis, which may represent functionally distinct areas.

  8. Regional glucose metabolism within cortical Brodmann areas in healthy individuals and autistic patients.

    Science.gov (United States)

    Hazlett, Erin A; Buchsbaum, Monte S; Hsieh, Pauline; Haznedar, M Mehmet; Platholi, Jimcy; LiCalzi, Elizabeth M; Cartwright, Charles; Hollander, Eric

    2004-01-01

    A new Brodmann area (BA) delineation approach was applied to FDG-PET scans of autistic patients and healthy volunteers (n = 17 in each group) to examine relative glucose metabolism (rGMR) during performance of a verbal memory task. In the frontal lobe, patients had lower rGMR in medial/cingulate regions (BA 32, 24, 25) but not in lateral regions (BA 8-10) compared with healthy controls. Patients had higher rGMR in occipital (BA 19) and parietal regions (BA 39) compared with controls, but there were no group differences in temporal lobe regions. Among controls, better recall and use of the semantic-clustering strategy was associated with greater lateral and medial frontal rGMR, while decreased rGMR in medial-frontal regions was associated with greater perseverative/intrusion errors. Patients failed to show these patterns. Autism patients have dysfunction in some but not all of the key brain regions subserving verbal memory performance, and other regions may be recruited for task performance. Copyright 2004 S. Karger AG, Basel

  9. Axono-cortical evoked potentials: A proof-of-concept study.

    Science.gov (United States)

    Mandonnet, E; Dadoun, Y; Poisson, I; Madadaki, C; Froelich, S; Lozeron, P

    2016-04-01

    Awake surgery is currently considered the best method to tailor intraparenchymatous resections according to functional boundaries. However, the exact mechanisms by which electrical stimulation disturbs behavior remain largely unknown. In this case report, we describe a new method to explore the propagation toward cortical sites of a brief pulse applied to an eloquent white matter pathway. We present a patient, operated on in awake condition for removal of a cavernoma of the left ventral premotor cortex. At the end of the resection, the application of 60Hz stimulation in the white matter of the operculum induced anomia. Stimulating the same site at a frequency of 1Hz during 70seconds allowed to record responses on electrodes put over Broca's area and around the inferior part of central sulcus. Axono-cortical evoked potentials were then obtained by averaging unitary responses, time-locked to the stimulus. We then discuss the origin of these evoked axono-cortical potentials and the likely pathway connecting the stimulation site to the recorded cortical sites.

  10. 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...

  11. Amplified somatosensory and visual cortical projections to a core auditory area, the anterior auditory field, following early- and late-onset deafness.

    Science.gov (United States)

    Wong, Carmen; Chabot, Nicole; Kok, Melanie A; Lomber, Stephen G

    2015-09-01

    Cross-modal reorganization following the loss of input from a sensory modality can recruit sensory-deprived cortical areas to process information from the remaining senses. Specifically, in early-deaf cats, the anterior auditory field (AAF) is unresponsive to auditory stimuli but can be activated by somatosensory and visual stimuli. Similarly, AAF neurons respond to tactile input in adult-deafened animals. To examine anatomical changes that may underlie this functional adaptation following early or late deafness, afferent projections to AAF were examined in hearing cats, and cats with early- or adult-onset deafness. Unilateral deposits of biotinylated dextran amine were made in AAF to retrogradely label cortical and thalamic afferents to AAF. In early-deaf cats, ipsilateral neuronal labeling in visual and somatosensory cortices increased by 329% and 101%, respectively. The largest increases arose from the anterior ectosylvian visual area and the anterolateral lateral suprasylvian visual area, as well as somatosensory areas S2 and S4. Consequently, labeling in auditory areas was reduced by 36%. The age of deafness onset appeared to influence afferent connectivity, with less marked differences observed in late-deaf cats. Profound changes to visual and somatosensory afferent connectivity following deafness may reflect corticocortical rewiring affording acoustically deprived AAF with cross-modal functionality.

  12. LANGUAGE-DRIVEN SPATIOTEMPORAL CAUSAL INTEGRATION IN THE PREFRONTAL AND PREMOTOR CORTICES MODULACIÓN LINGÜÍSTICA DE LA INTEGRACIÓN ESPACIO-TEMPORAL DE LA INFORMACIÓN CAUSAL EN LAS ÁREAS PREFRONTAL Y PREMOTORA DE LA CORTEZA CEREBRAL

    Directory of Open Access Journals (Sweden)

    ROBERTO LIMONGI TIRADO¹

    2011-01-01

    Full Text Available The behavioral literature has reported the differentiation between perceived causality and higher-order causal reasoning. The advent of modern technology such as functional magnetic resonance imaging and the theoretical framework of cognitive linguistics and behavioral experimental designs have raised new hypotheses and opened new possibilities to address the perceptual and higher-order distinction in causality. In this article, we discuss and integrate recent biological and psycholinguistic work on both perceptual and linguistic representations of causality that challenges the modular view of human causal knowledge. We suggest that linguistic and sensory-perceptual representations of causal events might coexist and interact in the brain. In this sense, whereas previous work proposes that the posterior areas of the brain automatically detect the spatiotemporal structure of visual causal events and that the frontal areas integrate such information in a causal representation, results from our research program suggest that this integration process is language-driven. Tw o different semantic representations of causative linguistic structures (lexical and periphrastic causatives might infuence cognitive control mechanisms, memory resources, and preparatory motor responses when observers evaluate the causal nature of visual stimuli.La bibliografía conductual ha reportado diferencias entre los procesos de percepción causal y procesos superiores de razonamiento causal. El desarrollo de nuevas tecnologías como la resonancia magnética nuclear funcional, la perspectiva teórica de la lingüística cognitiva y los diseños experimentales conductuales han propiciado nuevas hipótesis y abierto nuevas posibilidades para abordar la diferencia entre percepción causal y razonamiento causal. En este artículo discutimos e integramos los recientes avances biológicos y psicolingüísticos sobre las representaciones perceptuales y lingüísticas de la

  13. Histological features of layers and sublayers in cortical visual areas V1 and V2 of chimpanzees, macaque monkeys, and humans

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    Balaram P

    2014-09-01

    Full Text Available Pooja Balaram, Nicole A Young, Jon H Kaas Department of Psychology, Vanderbilt University, Nashville, TN, USA Abstract: The layers and sublayers of primary visual cortex, or V1, in primates are easily distinguishable compared to those in other cortical areas, and are especially distinct in anthropoid primates – monkeys, apes, and humans – where they also vary in histological appearance. This variation in primate-specific specialization has led to a longstanding confusion over the identity of layer 4 and its proposed sublayers in V1. As the application of different histological markers relate to the issue of defining and identifying layers and sublayers, we applied four traditional and four more recent histological markers to brain sections of V1 and adjoining secondary visual cortex (V2 in macaque monkeys, chimpanzees, and humans in order to compare identifiable layers and sublayers in both cortical areas across these species. The use of Nissl, neuronal nuclear antigen (NeuN, Gallyas myelin, cytochrome oxidase (CO, acetylcholinesterase (AChE, nonphosphorylated neurofilament H (SMI-32, parvalbumin (PV, and vesicular glutamate transporter 2 (VGLUT2 preparations support the conclusion that the most popular scheme of V1 lamination, that of Brodmann, misidentifies sublayers of layer 3 (3Bβ and 3C as sublayers of layer 4 (4A and 4B, and that the specialized sublayer of layer 3 in monkeys, 3Bβ, is not present in humans. These differences in interpretation are important as they relate to the proposed functions of layer 4 in primate species, where layer 4 of V1 is a layer that receives and processes information from the visual thalamus, and layer 3 is a layer that transforms and distributes information to other cortical areas. Keywords: area 17, area 18, cortical layers, histology, immunohistochemistry

  14. Birth Weight and Adult IQ, but Not Anxious-Depressive Psychopathology, Are Associated with Cortical Surface Area: A Study in Twins.

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    Aldo Córdova-Palomera

    Full Text Available Previous research suggests that low birth weight (BW induces reduced brain cortical surface area (SA which would persist until at least early adulthood. Moreover, low BW has been linked to psychiatric disorders such as depression and psychological distress, and to altered neurocognitive profiles.We present novel findings obtained by analysing high-resolution structural MRI scans of 48 twins; specifically, we aimed: i to test the BW-SA association in a middle-aged adult sample; and ii to assess whether either depression/anxiety disorders or intellectual quotient (IQ influence the BW-SA link, using a monozygotic (MZ twin design to separate environmental and genetic effects.Both lower BW and decreased IQ were associated with smaller total and regional cortical SA in adulthood. Within a twin pair, lower BW was related to smaller total cortical and regional SA. In contrast, MZ twin differences in SA were not related to differences in either IQ or depression/anxiety disorders.The present study supports findings indicating that i BW has a long-lasting effect on cortical SA, where some familial and environmental influences alter both foetal growth and brain morphology; ii uniquely environmental factors affecting BW also alter SA; iii higher IQ correlates with larger SA; and iv these effects are not modified by internalizing psychopathology.

  15. Birth Weight and Adult IQ, but Not Anxious-Depressive Psychopathology, Are Associated with Cortical Surface Area: A Study in Twins

    Science.gov (United States)

    Córdova-Palomera, Aldo; Fatjó-Vilas, Mar; Falcón, Carles; Bargalló, Nuria; Alemany, Silvia; Crespo-Facorro, Benedicto; Nenadic, Igor; Fañanás, Lourdes

    2015-01-01

    Background Previous research suggests that low birth weight (BW) induces reduced brain cortical surface area (SA) which would persist until at least early adulthood. Moreover, low BW has been linked to psychiatric disorders such as depression and psychological distress, and to altered neurocognitive profiles. Aims We present novel findings obtained by analysing high-resolution structural MRI scans of 48 twins; specifically, we aimed: i) to test the BW-SA association in a middle-aged adult sample; and ii) to assess whether either depression/anxiety disorders or intellectual quotient (IQ) influence the BW-SA link, using a monozygotic (MZ) twin design to separate environmental and genetic effects. Results Both lower BW and decreased IQ were associated with smaller total and regional cortical SA in adulthood. Within a twin pair, lower BW was related to smaller total cortical and regional SA. In contrast, MZ twin differences in SA were not related to differences in either IQ or depression/anxiety disorders. Conclusion The present study supports findings indicating that i) BW has a long-lasting effect on cortical SA, where some familial and environmental influences alter both foetal growth and brain morphology; ii) uniquely environmental factors affecting BW also alter SA; iii) higher IQ correlates with larger SA; and iv) these effects are not modified by internalizing psychopathology. PMID:26086820

  16. Modulation of physiological mirror activity with transcranial direct current stimulation over dorsal premotor cortex.

    Science.gov (United States)

    Beaulé, Vincent; Tremblay, Sara; Lafleur, Louis-Philippe; Ferland, Marie C; Lepage, Jean-François; Théoret, Hugo

    2016-11-01

    Humans have a natural tendency towards symmetrical movements, which rely on a distributed cortical network that allows for complex unimanual movements. Studies on healthy humans using rTMS have shown that disruption of this network, and particularly the dorsal premotor cortex (dPMC), can result in increased physiological mirror movements. The aim of the present set of experiments was to further investigate the role of dPMC in restricting motor output to the contralateral hand and determine whether physiological mirror movements could be decreased in healthy individuals. Physiological mirror movements were assessed before and after transcranial direct current stimulation (tDCS) over right and left dPMC in three conditions: bilateral, unilateral left and unilateral right stimulation. Mirror EMG activity was assessed immediately before, 0, 10 and 20 min after tDCS. Results show that physiological mirroring increased significantly in the hand ipsilateral to cathodal stimulation during bilateral stimulation of the dPMC, 10 and 20 min after stimulation compared to baseline. There was no significant modulation of physiological mirroring in the hand ipsilateral to anodal stimulation in the bilateral condition or following unilateral anodal or unilateral cathodal stimulation. The present data further implicate the dPMC in the control of unimanual hand movements and show that physiological mirroring can be increased but not decreased with dPMC tDCS.

  17. A shared representation of the space near oneself and others in the human premotor cortex.

    Science.gov (United States)

    Brozzoli, Claudio; Gentile, Giovanni; Bergouignan, Loretxu; Ehrsson, H Henrik

    2013-09-23

    Interactions between people require shared high-level cognitive representations of action goals, intentions, and mental states, but do people also share their representation of space? The human ventral premotor (PMv) and parietal cortices contain neuronal populations coding for the execution and observation of actions, analogous to the mirror neurons identified in monkeys. This neuronal system is tuned to the location of the acting person relative to the observer and the target of the action. Therefore, it can be theorized that the observer's brain constructs a low-level, body-centered representation of the space around others similar to one's own peripersonal space representation. Single-cell recordings have reported that parietal visuotactile neurons discharge for objects near specific parts of a monkey's own body and near the corresponding body parts of another individual. In humans, no neuroimaging study has investigated this issue. Here, we identified neuronal populations in the human PMv that encode the space near both one's own hand and another person's hand. The shared peripersonal space representation could support social interactions by coding sensory events, actions, and cognitive processes in a common spatial reference frame.

  18. Inhibitory stimulation of the ventral premotor cortex temporarily interferes with musical beat rate preference.

    Science.gov (United States)

    Kornysheva, Katja; von Anshelm-Schiffer, Anne-Marike; Schubotz, Ricarda I

    2011-08-01

    Behavioral studies suggest that preference for a beat rate (tempo) in auditory sequences is tightly linked to the motor system. However, from a neuroscientific perspective the contribution of motor-related brain regions to tempo preference in the auditory domain remains unclear. A recent fMRI study (Kornysheva et al. [2010]: Hum Brain Mapp 31:48-64) revealed that the activity increase in the left ventral premotor cortex (PMv) is associated with the preference for a tempo of a musical rhythm. The activity increase correlated with how strongly the subjects preferred a tempo. Despite this evidence, it remains uncertain whether an interference with activity in the left PMv affects tempo preference strength. Consequently, we conducted an offline repetitive transcranial magnetic stimulation (rTMS) study, in which the cortical excitability in the left PMv was temporarily reduced. As hypothesized, 0.9 Hz rTMS over the left PMv temporarily affected individual tempo preference strength depending on the individual strength of tempo preference in the control session. Moreover, PMv stimulation temporarily interfered with the stability of individual tempo preference strength within and across sessions. These effects were specific to the preference for tempo in contrast to the preference for timbre, bound to the first half of the experiment following PMv stimulation and could not be explained by an impairment of tempo recognition. Our results corroborate preceding fMRI findings and suggest that activity in the left PMv is part of a network that affects the strength of beat rate preference.

  19. Inhibition of the dorsal premotor cortex does not repair surround inhibition in writer's cramp patients.

    Science.gov (United States)

    Veugen, Lidwien C; Hoffland, Britt S; Stegeman, Dick F; van de Warrenburg, Bart P

    2013-03-01

    Writer's cramp is a task-specific form of focal dystonia, characterized by abnormal movements and postures of the hand and arm during writing. Two consistent abnormalities in its pathophysiology are a loss of surround inhibition and overactivity of the dorsal premotor cortex (PMd). This study aimed to assess a possible link between these two phenomena by investigating whether PMd inhibition leads to an improvement of surround inhibition, in parallel with previously demonstrated writing improvement. Fifteen writer's cramp patients and ten controls performed a simple motor hand task during which surround inhibition was measured using transcranial magnetic stimulation. Motor cortical excitability was measured of the active and surround muscles at three phases of the task. Surround inhibition and writing performance were assessed before and after PMd inhibitory continuous theta burst stimulation. In contrast to healthy controls, patients did not show inhibition of the abductor digiti minimi muscle during movement initiation of the first dorsal interosseus muscle, confirming the loss of surround inhibition. PMd inhibition led to an improvement of writing speed in writer's cramp patients. However, in both groups, no changes in surround inhibition were observed. The results confirm a role for the PMd in the pathophysiology of writer's cramp. We show that PMd inhibition does not lead to restoration of the surround inhibition defect in writer's cramp, despite the improvement in writing. This questions the involvement of the PMd in the loss of surround inhibition, and perhaps also the direct link between surround inhibition and dystonia.

  20. Cortical cell and neuron density estimates in one chimpanzee hemisphere.

    Science.gov (United States)

    Collins, Christine E; Turner, Emily C; Sawyer, Eva Kille; Reed, Jamie L; Young, Nicole A; Flaherty, David K; Kaas, Jon H

    2016-01-19

    The density of cells and neurons in the neocortex of many mammals varies across cortical areas and regions. This variability is, perhaps, most pronounced in primates. Nonuniformity in the composition of cortex suggests regions of the cortex have different specializations. Specifically, regions with densely packed neurons contain smaller neurons that are activated by relatively few inputs, thereby preserving information, whereas regions that are less densely packed have larger neurons that have more integrative functions. Here we present the numbers of cells and neurons for 742 discrete locations across the neocortex in a chimpanzee. Using isotropic fractionation and flow fractionation methods for cell and neuron counts, we estimate that neocortex of one hemisphere contains 9.5 billion cells and 3.7 billion neurons. Primary visual cortex occupies 35 cm(2) of surface, 10% of the total, and contains 737 million densely packed neurons, 20% of the total neurons contained within the hemisphere. Other areas of high neuron packing include secondary visual areas, somatosensory cortex, and prefrontal granular cortex. Areas of low levels of neuron packing density include motor and premotor cortex. These values reflect those obtained from more limited samples of cortex in humans and other primates.

  1. The human premotor cortex is 'mirror' only for biological actions.

    Science.gov (United States)

    Tai, Yen F; Scherfler, Christoph; Brooks, David J; Sawamoto, Nobukatsu; Castiello, Umberto

    2004-01-20

    Previous work has shown that both human adults and children attend to grasping actions performed by another person but not necessarily to those made by a mechanical device. According to recent neurophysiological data, the monkey premotor cortex contains "mirror" neurons that discharge both when the monkey performs specific manual grasping actions and when it observes another individual performing the same or similar actions. However, when a human model uses tools to perform grasping actions, the mirror neurons are not activated. A similar "mirror" system has been described in humans, but whether or not it is also tuned specifically to biological actions has never been tested. Here we show that when subjects observed manual grasping actions performed by a human model a significant neural response was elicited in the left premotor cortex. This activation was not evident for the observation of grasping actions performed by a robot model commanded by an experimenter. This result indicates for the first time that in humans the mirror system is biologically tuned. This system appears to be the neural substrate for biological preference during action coding.

  2. Functional connectivity of human premotor and motor cortex explored with repetitive transcranial magnetic stimulation.

    NARCIS (Netherlands)

    Munchau, A.; Bloem, B.R.; Irlbacher, K.; Trimble, M.R.; Rothwell, J.C.

    2002-01-01

    Connections between the premotor cortex and the primary motor cortex are dense and are important in the visual guidance of arm movements. We have shown previously that it is possible to engage these connections in humans and to measure the net amount of inhibition/facilitation from premotor to motor

  3. Maintaining Gait Performance by Cortical Activation during Dual-Task Interference: A Functional Near-Infrared Spectroscopy Study.

    Directory of Open Access Journals (Sweden)

    Chia-Feng Lu

    Full Text Available In daily life, mobility requires walking while performing a cognitive or upper-extremity motor task. Although previous studies have evaluated the effects of dual tasks on gait performance, few studies have evaluated cortical activation and its association with gait disturbance during dual tasks. In this study, we simultaneously assessed gait performance and cerebral oxygenation in the bilateral prefrontal cortices (PFC, premotor cortices (PMC, and supplemental motor areas (SMA, using functional near-infrared spectroscopy, in 17 young adults performing dual tasks. Each participant was evaluated while performing normal-pace walking (NW, walking while performing a cognitive task (WCT, and walking while performing a motor task (WMT. Our results indicated that the left PFC exhibited the strongest and most sustained activation during WCT, and that NW and WMT were associated with minor increases in oxygenation levels during their initial phases. We observed increased activation in channels in the SMA and PMC during WCT and WMT. Gait data indicated that WCT and WMT both caused reductions in walking speed, but these reductions resulted from differing alterations in gait properties. WCT was associated with significant changes in cadence, stride time, and stride length, whereas WMT was associated with reductions in stride length only. During dual-task activities, increased activation of the PMC and SMA correlated with declines in gait performance, indicating a control mechanism for maintaining gait performance during dual tasks. Thus, the regulatory effects of cortical activation on gait behavior enable a second task to be performed while walking.

  4. Maintaining Gait Performance by Cortical Activation during Dual-Task Interference: A Functional Near-Infrared Spectroscopy Study.

    Science.gov (United States)

    Lu, Chia-Feng; Liu, Yan-Ci; Yang, Yea-Ru; Wu, Yu-Te; Wang, Ray-Yau

    2015-01-01

    In daily life, mobility requires walking while performing a cognitive or upper-extremity motor task. Although previous studies have evaluated the effects of dual tasks on gait performance, few studies have evaluated cortical activation and its association with gait disturbance during dual tasks. In this study, we simultaneously assessed gait performance and cerebral oxygenation in the bilateral prefrontal cortices (PFC), premotor cortices (PMC), and supplemental motor areas (SMA), using functional near-infrared spectroscopy, in 17 young adults performing dual tasks. Each participant was evaluated while performing normal-pace walking (NW), walking while performing a cognitive task (WCT), and walking while performing a motor task (WMT). Our results indicated that the left PFC exhibited the strongest and most sustained activation during WCT, and that NW and WMT were associated with minor increases in oxygenation levels during their initial phases. We observed increased activation in channels in the SMA and PMC during WCT and WMT. Gait data indicated that WCT and WMT both caused reductions in walking speed, but these reductions resulted from differing alterations in gait properties. WCT was associated with significant changes in cadence, stride time, and stride length, whereas WMT was associated with reductions in stride length only. During dual-task activities, increased activation of the PMC and SMA correlated with declines in gait performance, indicating a control mechanism for maintaining gait performance during dual tasks. Thus, the regulatory effects of cortical activation on gait behavior enable a second task to be performed while walking.

  5. Cortical motor hand area. Validation of functional magnetic resonance imaging by intraoperative cortical stimulation mapping; Das motorische Handareal. Nichtinvasiver Nachweis mittels fMRT und operative Validierung mit kortikaler Stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Yousry, T. [Inst. fuer Radiologische Diagnostik, Klinikum Grosshadern, Univ. Muenchen (Germany); Schmid, U.D. [Neurochirurgische Klinik, Klinikum Grosshadern, Univ. Muenchen (Germany); Schmidt, D. [Inst. fuer Radiologische Diagnostik, Klinikum Grosshadern, Univ. Muenchen (Germany); Heiss, D. [Inst. fuer Radiologische Diagnostik, Klinikum Innenstadt, Univ. Muenchen (Germany); Jassoy, A. [Inst. fuer Radiologische Diagnostik, Klinikum Innenstadt, Univ. Muenchen (Germany); Eisner, W. [Neurochirurgische Klinik, Klinikum Grosshadern, Univ. Muenchen (Germany); Reulen, H.J. [Neurochirurgische Klinik, Klinikum Grosshadern, Univ. Muenchen (Germany); Reiser, M. [Inst. fuer Radiologische Diagnostik, Klinikum Grosshadern, Univ. Muenchen (Germany)

    1995-04-01

    In this study, activation of cortical sites by specific motor tasks (opening and closing of the hand) was examined by fMRI utilizing the blood-oxygen-level-dependent (BOLD) technique. fMRI was employed in five volunteers and in six patients with tumors in the vicinity of the central region. In the patients, the fMRI data and intraoperative cortical mapping were compared. Our results indicate good correlation of these two methods and that there are no significant differences in the localization of the motor hand area. (orig.) [Deutsch] Die funktionelle Magnetresonanztomographie (fMRT) ermoeglicht die nichtinvasive Lokalisation bestimmter Hirnfunktionen mit hoher raeumlicher Aufloesung. Um zu ueberpruefen, ob die mittels fMRT dargestellten Signalintensitaetsaenderungen wirklich dem Repraesentationsareal einer definierten Funktion entspricht, verglichen wir bei einem Patientenkollektiv die Resultate der fMRT mit den Ergebnissen der intraoperativen motorischen Kortexstimulation. Es zeigte sich, dass Lokalisation und Ausdehnung des von uns untersuchten motorischen Handareals bei beiden Methoden uebereinstimmte. Unsere Ergebnisse zeigen, dass die kortikale Repraesentation des motorischen Handareals durch fMRT mit hoher raeumlicher Aufloesung und nichtinvasiv lokalisiert werden kann. (orig.)

  6. Functional MRI of the immediate impact of transcranial magnetic stimulation on cortical and subcortical motor circuits.

    Science.gov (United States)

    Bestmann, Sven; Baudewig, Jürgen; Siebner, Hartwig R; Rothwell, John C; Frahm, Jens

    2004-04-01

    Recent studies indicate that the cortical effects of transcranial magnetic stimulation (TMS) may not be localized to the site of stimulation, but spread to other distant areas. Using echo-planar imaging with blood-oxygenation-level-dependent (BOLD) contrast at 3 Tesla, we measured MRI signal changes in cortical and subcortical motor regions during high-frequency (3.125 Hz) repetitive TMS (rTMS) of the left sensorimotor cortex (M1/S1) at intensities above and below the active motor threshold in healthy humans. The supra- and subthreshold nature of the TMS pulses was confirmed by simultaneous electromyographic monitoring of a hand muscle. Suprathreshold rTMS activated a network of primary and secondary cortical motor regions including M1/S1, supplementary motor area, dorsal premotor cortex, cingulate motor area, the putamen and thalamus. Subthreshold rTMS elicited no MRI-detectable activity in the stimulated M1/S1, but otherwise led to a similar activation pattern as obtained for suprathreshold stimulation though at reduced intensity. In addition, we observed activations within the auditory system, including the transverse and superior temporal gyrus, inferior colliculus and medial geniculate nucleus. The present findings support the notion that re-afferent feedback from evoked movements represents the dominant input to the motor system via M1 during suprathreshold stimulation. The BOLD MRI changes in motor areas distant from the site of subthreshold stimulation are likely to originate from altered synaptic transmissions due to induced excitability changes in M1/S1. They reflect the capability of rTMS to target both local and remote brain regions as tightly connected constituents of a cortical and subcortical network.

  7. Centrality of prefrontal and motor preparation cortices to Tourette Syndrome revealed by meta-analysis of task-based neuroimaging studies.

    Science.gov (United States)

    Polyanska, Liliana; Critchley, Hugo D; Rae, Charlotte L

    2017-01-01

    Tourette Syndrome (TS) is a neurodevelopmental condition characterized by chronic multiple tics, which are experienced as compulsive and 'unwilled'. Patients with TS can differ markedly in the frequency, severity, and bodily distribution of tics. Moreover, there are high comorbidity rates with attention deficit hyperactivity disorder (ADHD), obsessive compulsive disorder (OCD), anxiety disorders, and depression. This complex clinical profile may account for apparent variability of findings across neuroimaging studies that connect neural function to cognitive and motor behavior in TS. Here we crystalized information from neuroimaging regarding the functional circuitry of TS, and furthermore, tested specifically for neural determinants of tic severity, by applying activation likelihood estimation (ALE) meta-analyses to neuroimaging (activation) studies of TS. Fourteen task-based studies (13 fMRI and one H2O-PET) met rigorous inclusion criteria. These studies, encompassing 25 experiments and 651 participants, tested for differences between TS participants and healthy controls across cognitive, motor, perceptual and somatosensory domains. Relative to controls, TS participants showed distributed differences in the activation of prefrontal (inferior, middle, and superior frontal gyri), anterior cingulate, and motor preparation cortices (lateral premotor cortex and supplementary motor area; SMA). Differences also extended into sensory (somatosensory cortex and the lingual gyrus; V4); and temporo-parietal association cortices (posterior superior temporal sulcus, supramarginal gyrus, and retrosplenial cortex). Within TS participants, tic severity (reported using the Yale Global Tic Severity Scale; YGTSS) selectively correlated with engagement of SMA, precentral gyrus, and middle frontal gyrus across tasks. The dispersed involvement of multiple cortical regions with differences in functional reactivity may account for heterogeneity in the symptomatic expression of TS and its

  8. Endogenous cortical rhythms determine cerebral specialization for speech perception and production

    DEFF Research Database (Denmark)

    Giraud, Anne-Lise; Kleinschmidt, Andreas; Poeppel, David

    2007-01-01

    Across multiple timescales, acoustic regularities of speech match rhythmic properties of both the auditory and motor systems. Syllabic rate corresponds to natural jaw-associated oscillatory rhythms, and phonemic length could reflect endogenous oscillatory auditory cortical properties. Hemispheric...... that spontaneous EEG power variations within the gamma range (phonemic rate) correlate best with left auditory cortical synaptic activity, while fluctuations within the theta range correlate best with that in the right. Power fluctuations in both ranges correlate with activity in the mouth premotor region...

  9. Cortical networks for visual reaching: physiological and anatomical organization of frontal and parietal lobe arm regions.

    Science.gov (United States)

    Johnson, P B; Ferraina, S; Bianchi, L; Caminiti, R

    1996-01-01

    The functional and structural properties of the dorsolateral frontal lobe and posterior parietal proximal arm representations were studied in macaque monkeys. Physiological mapping of primary motor (MI), dorsal premotor (PMd), and posterior parietal (area 5) cortices was performed in behaving monkeys trained in an instructed-delay reaching task. The parietofrontal corticocortical connectivities of these same areas were subsequently examined anatomically by means of retrograde tracing techniques. Signal-, set-, movement-, and position-related directional neuronal activities were distributed nonuniformly within the task-related areas in both frontal and parietal cortices. Within the frontal lobe, moving caudally from PMd to the MI, the activity that signals for the visuo-spatial events leading to target localization decreased, while the activity more directly linked to movement generation increased. Physiological recordings in the superior parietal lobule revealed a gradient-like distribution of functional properties similar to that observed in the frontal lobe. Signal- and set-related activities were encountered more frequently in the intermediate and ventral part of the medial bank of the intraparietal sulcus (IPS), in area MIP. Movement-and position-related activities were distributed more uniformly within the superior parietal lobule (SPL), in both dorsal area 5 and in MIP. Frontal and parietal regions sharing similar functional properties were preferentially connected through their association pathways. As a result of this study, area MIP, and possibly areas MDP and 7m as well, emerge as the parietal nodes by which visual information may be relayed to the frontal lobe arm region. These parietal and frontal areas, along with their association connections, represent a potential cortical network for visual reaching. The architecture of this network is ideal for coding reaching as the result of a combination between visual and somatic information.

  10. Neural encoding of auditory discrimination in ventral premotor cortex

    Science.gov (United States)

    Lemus, Luis; Hernández, Adrián; Romo, Ranulfo

    2009-01-01

    Monkeys have the capacity to accurately discriminate the difference between two acoustic flutter stimuli. In this task, monkeys must compare information about the second stimulus to the memory trace of the first stimulus, and must postpone the decision report until a sensory cue triggers the beginning of the decision motor report. The neuronal processes associated with the different components of this task have been investigated in the primary auditory cortex (A1); but, A1 seems exclusively associated with the sensory and not with the working memory and decision components of this task. Here, we show that ventral premotor cortex (VPC) neurons reflect in their activities the current and remembered acoustic stimulus, their comparison, and the result of the animal's decision report. These results provide evidence that the neural dynamics of VPC is involved in the processing steps that link sensation and decision-making during auditory discrimination. PMID:19667191

  11. Altered Cortical Swallowing Processing in Patients with Functional Dysphagia: A Preliminary Study

    Science.gov (United States)

    Wollbrink, Andreas; Warnecke, Tobias; Winkels, Martin; Pantev, Christo; Dziewas, Rainer

    2014-01-01

    Objective Current neuroimaging research on functional disturbances provides growing evidence for objective neuronal correlates of allegedly psychogenic symptoms, thereby shifting the disease concept from a psychological towards a neurobiological model. Functional dysphagia is such a rare condition, whose pathogenetic mechanism is largely unknown. In the absence of any organic reason for a patient's persistent swallowing complaints, sensorimotor processing abnormalities involving central neural pathways constitute a potential etiology. Methods In this pilot study we measured cortical swallow-related activation in 5 patients diagnosed with functional dysphagia and a matched group of healthy subjects applying magnetoencephalography. Source localization of cortical activation was done with synthetic aperture magnetometry. To test for significant differences in cortical swallowing processing between groups, a non-parametric permutation test was afterwards performed on individual source localization maps. Results Swallowing task performance was comparable between groups. In relation to control subjects, in whom activation was symmetrically distributed in rostro-medial parts of the sensorimotor cortices of both hemispheres, patients showed prominent activation of the right insula, dorsolateral prefrontal cortex and lateral premotor, motor as well as inferolateral parietal cortex. Furthermore, activation was markedly reduced in the left medial primary sensory cortex as well as right medial sensorimotor cortex and adjacent supplementary motor area (pdysphagia - a condition with assumed normal brain function - seems to be associated with distinctive changes of the swallow-related cortical activation pattern. Alterations may reflect exaggerated activation of a widely distributed vigilance, self-monitoring and salience rating network that interferes with down-stream deglutition sensorimotor control. PMID:24586948

  12. Cortical thickness maturation and duration of music training: health-promoting activities shape brain development.

    Science.gov (United States)

    Hudziak, James J; Albaugh, Matthew D; Ducharme, Simon; Karama, Sherif; Spottswood, Margaret; Crehan, Eileen; Evans, Alan C; Botteron, Kelly N

    2014-11-01

    To assess the extent to which playing a musical instrument is associated with cortical thickness development among healthy youths. Participants were part of the National Institutes of Health (NIH) Magnetic Resonance Imaging (MRI) Study of Normal Brain Development. This study followed a longitudinal design such that participants underwent MRI scanning and behavioral testing on up to 3 separate visits, occurring at 2-year intervals. MRI, IQ, and music training data were available for 232 youths (334 scans), ranging from 6 to 18 years of age. Cortical thickness was regressed against the number of years that each youth had played a musical instrument. Next, thickness was regressed against an "Age × Years of Playing" interaction term. Age, gender, total brain volume, and scanner were controlled for in analyses. Participant ID was entered as a random effect to account for within-person dependence. False discovery rate correction was applied (p ≤ .05). There was no association between thickness and years playing a musical instrument. The "Age × Years of Playing" interaction was associated with thickness in motor, premotor, and supplementary motor cortices, as well as prefrontal and parietal cortices. Follow-up analysis revealed that music training was associated with an increased rate of thickness maturation. Results were largely unchanged when IQ and handedness were included as covariates. Playing a musical instrument was associated with more rapid cortical thickness maturation within areas implicated in motor planning and coordination, visuospatial ability, and emotion and impulse regulation. However, given the quasi-experimental nature of this study, we cannot rule out the influence of confounding variables. Copyright © 2014 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.

  13. Functional connectivity of the human rostral and caudal cingulate motor areas in the brain resting state at 3T

    Energy Technology Data Exchange (ETDEWEB)

    Habas, Christophe [CHNO des Quinze-Vingts, UPMC Paris 6, Service de NeuroImagerie, Paris (France)

    2010-01-15

    Three cingulate motor areas have been described in monkeys, the rostral, dorsal, and ventral cingulate motor areas, and would control limbic-related motor activity. However, little anatomical data are available in human about the functional networks these cingulate areas underlie. Therefore, networks anchored in the rostral and caudal cingulate motor areas (rCMA and cCMA, respectively) were studied in human using functional connectivity during the brain resting state. Since the rCMA and cCMA are located just under the pre-supplementary and supplementary motor areas (pre-SMA and SMA), the pre-SMA- and SMA-centered networks were also studied to ensure that these four circuits were correctly dissociated. Data from 14 right-handed healthy volunteers were acquired at rest and analyzed by region of interest (ROI)-based functional connectivity. The blood oxygenation level-dependent (BOLD) signal fluctuations of separate ROIs located in rCMA, cCMA, pre-SMA, and SMA were successively used to identify significant temporal correlations with BOLD signal fluctuations of other brain regions. Low-frequency BOLD signal of the CMA was correlated with signal fluctuations in the prefrontal, cingulate, insular, premotor, motor, medial and inferior parietal cortices, putamen and thalamus, and anticorrelated with the default-mode network. rCMA was more in relation with prefrontal, orbitofrontal, and language-associated cortices than cCMA more related to sensory cortex. These cingulate networks were very similar to the pre-SMA- and SMA-centered networks, although pre-SMA and SMA showed stronger correlation with the prefrontal and inferior parietal cortices and with the cerebellum and the superior parietal cortex, respectively. The human cingulate motor areas constitute an interface between sensorimotor, limbic and executive systems, sharing common cortical, striatal, and thalamic relays with the overlying premotor medial areas. (orig.)

  14. Histological features of layers and sublayers in cortical visual areas V1 and V2 of chimpanzees, macaque monkeys, and humans.

    Science.gov (United States)

    Balaram, Pooja; Young, Nicole A; Kaas, Jon H

    2014-09-01

    The layers and sublayers of primary visual cortex, or V1, in primates are easily distinguishable compared to those in other cortical areas, and are especially distinct in anthropoid primates - monkeys, apes, and humans - where they also vary in histological appearance. This variation in primate-specific specialization has led to a longstanding confusion over the identity of layer 4 and its proposed sublayers in V1. As the application of different histological markers relate to the issue of defining and identifying layers and sublayers, we applied four traditional and four more recent histological markers to brain sections of V1 and adjoining secondary visual cortex (V2) in macaque monkeys, chimpanzees, and humans in order to compare identifiable layers and sublayers in both cortical areas across these species. The use of Nissl, neuronal nuclear antigen (NeuN), Gallyas myelin, cytochrome oxidase (CO), acetylcholinesterase (AChE), nonphosphorylated neurofilament H (SMI-32), parvalbumin (PV), and vesicular glutamate transporter 2 (VGLUT2) preparations support the conclusion that the most popular scheme of V1 lamination, that of Brodmann, misidentifies sublayers of layer 3 (3Bβ and 3C) as sublayers of layer 4 (4A and 4B), and that the specialized sublayer of layer 3 in monkeys, 3Bβ, is not present in humans. These differences in interpretation are important as they relate to the proposed functions of layer 4 in primate species, where layer 4 of V1 is a layer that receives and processes information from the visual thalamus, and layer 3 is a layer that transforms and distributes information to other cortical areas.

  15. [Cortical blindness].

    Science.gov (United States)

    Chokron, S

    2014-02-01

    Cortical blindness refers to a visual loss induced by a bilateral occipital lesion. The very strong cooperation between psychophysics, cognitive psychology, neurophysiology and neuropsychology these latter twenty years as well as recent progress in cerebral imagery have led to a better understanding of neurovisual deficits, such as cortical blindness. It thus becomes possible now to propose an earlier diagnosis of cortical blindness as well as new perspectives for rehabilitation in children as well as in adults. On the other hand, studying complex neurovisual deficits, such as cortical blindness is a way to infer normal functioning of the visual system.

  16. Effective connectivity analysis demonstrates involvement of premotor cortex during speech perception.

    Science.gov (United States)

    Osnes, Berge; Hugdahl, Kenneth; Specht, Karsten

    2011-02-01

    Several reports of premotor cortex involvement in speech perception have been put forward. Still, the functional role of premotor cortex is under debate. In order to investigate the functional role of premotor cortex, we presented parametrically varied speech stimuli in both a behavioral and functional magnetic resonance imaging (fMRI) study. White noise was transformed over seven distinct steps into a speech sound and presented to the participants in a randomized order. As control condition served the same transformation from white noise into a music instrument sound. The fMRI data were modelled with Dynamic Causal Modeling (DCM) where the effective connectivity between Heschl's gyrus, planum temporale, superior temporal sulcus and premotor cortex were tested. The fMRI results revealed a graded increase in activation in the left superior temporal sulcus. Premotor cortex activity was only present at an intermediate step when the speech sounds became identifiable but were still distorted but was not present when the speech sounds were clearly perceivable. A Bayesian model selection procedure favored a model that contained significant interconnections between Heschl's gyrus, planum temporal, and superior temporal sulcus when processing speech sounds. In addition, bidirectional connections between premotor cortex and superior temporal sulcus and from planum temporale to premotor cortex were significant. Processing non-speech sounds initiated no significant connections to premotor cortex. Since the highest level of motor activity was observed only when processing identifiable sounds with incomplete phonological information, it is concluded that premotor cortex is not generally necessary for speech perception but may facilitate interpreting a sound as speech when the acoustic input is sparse.

  17. Evolution of cortical neurogenesis.

    Science.gov (United States)

    Abdel-Mannan, Omar; Cheung, Amanda F P; Molnár, Zoltán

    2008-03-18

    The neurons of the mammalian neocortex are organised into six layers. By contrast, the reptilian and avian dorsal cortices only have three layers which are thought to be equivalent to layers I, V and VI of mammals. Increased repertoire of mammalian higher cognitive functions is likely a result of an expanded cortical surface area. The majority of cortical cell proliferation in mammals occurs in the ventricular zone (VZ) and subventricular zone (SVZ), with a small number of scattered divisions outside the germinal zone. Comparative developmental studies suggest that the appearance of SVZ coincides with the laminar expansion of the cortex to six layers, as well as the tangential expansion of the cortical sheet seen within mammals. In spite of great variation and further compartmentalisation in the mitotic compartments, the number of neurons in an arbitrary cortical column appears to be remarkably constant within mammals. The current challenge is to understand how the emergence and elaboration of the SVZ has contributed to increased cortical cell diversity, tangential expansion and gyrus formation of the mammalian neocortex. This review discusses neurogenic processes that are believed to underlie these major changes in cortical dimensions in vertebrates.

  18. Mitotic Events in Cerebellar Granule Progenitor Cells that Expand Cerebellar Surface Area Are Critical for Normal Cerebellar Cortical Lamination in Mice

    Science.gov (United States)

    Chang, Joshua C.; Leung, Mark; Gokozan, Hamza Numan; Gygli, Patrick Edwin; Catacutan, Fay Patsy; Czeisler, Catherine; Otero, José Javier

    2015-01-01

    Late embryonic and postnatal cerebellar folial surface area expansion promotes cerebellar cortical cytoarchitectural lamination. We developed a streamlined sampling scheme to generate unbiased estimates of murine cerebellar surface area and volume using stereological principles. We demonstrate that during the proliferative phase of the external granule layer (EGL) and folial surface area expansion, EGL thickness does not change and thus is a topological proxy for progenitor self-renewal. The topological constraints indicate that during proliferative phases, migration out of the EGL is balanced by self-renewal. Progenitor self-renewal must, therefore, include mitotic events yielding either 2 cells in the same layer to increase surface area (β-events) and mitotic events yielding 2 cells, with 1 cell in a superficial layer and 1 cell in a deeper layer (α-events). As the cerebellum grows, therefore, β-events lie upstream of α-events. Using a mathematical model constrained by the measurements of volume and surface area, we could quantify inter-mitotic times for β-events on a per-cell basis in post-natal mouse cerebellum. Furthermore, we found that loss of CCNA2, which decreases EGL proliferation and secondarily induces cerebellar cortical dyslamination, shows preserved α-type events. Thus, CCNA2-null cerebellar granule progenitor cells are capable of self-renewal of the EGL stem cell niche; this is concordant with prior findings of extensive apoptosis in CCNA2-null mice. Similar methodologies may provide another layer of depth to the interpretation of results from stereological studies. PMID:25668568

  19. Transcallosal connection patterns of opposite dorsal premotor regions support a lateralized specialization for action and perception

    NARCIS (Netherlands)

    van der Hoorn, Anouk; Potgieser, Adriaan R. E.; de Jong, Bauke M.

    Lateralization of higher brain functions requires that a dominant hemisphere collects relevant information from both sides. The right dorsal premotor cortex (PMd), particularly implicated in visuomotor transformations, was hypothesized to be optimally located to converge visuospatial information

  20. Effects of sympathetic stimulation on the rhythmical jaw movements produced by electrical stimulation of the cortical masticatory areas of rabbits.

    Science.gov (United States)

    Roatta, S; Windhorst, U; Djupsjöbacka, M; Lytvynenko, S; Passatore, M

    2005-03-01

    The somatomotor and sympathetic nervous systems are intimately linked. One example is the influence of peripheral sympathetic fibers on the discharge characteristics of muscle spindles. Since muscle spindles play important roles in various motor behaviors, including rhythmic movements, the working hypothesis of this research was that changes in sympathetic outflow to muscle spindles can change rhythmic movement patterns. We tested this hypothesis in the masticatory system of rabbits. Rhythmic jaw movements and EMG activity induced by long-lasting electrical cortical stimulation were powerfully modulated by electrical stimulation of the peripheral stump of the cervical sympathetic nerve (CSN). This modulation manifested itself as a consistent and marked reduction in the excursion of the mandibular movements (often preceded by a transient modest enhancement), which could be attributed mainly to corresponding changes in masseter muscle activity. These changes outlasted the duration of CSN stimulation. In some of the cortically evoked rhythmic jaw movements (CRJMs) changes in masticatory frequency were also observed. When the jaw-closing muscles were subjected to repetitive ramp-and-hold force pulses, the CRMJs changed characteristics. Masseter EMG activity was strongly enhanced and digastric EMG slightly decreased. This change was considerably depressed during CSN stimulation. These effects of CSN stimulation are similar in sign and time course to the depression exerted by sympathetic activity on the jaw-closing muscle spindle discharge. It is suggested that the change in proprioceptive information induced by an increase in sympathetic outflow (a) has important implications even under normal conditions for the control of motor function in states of high sympathetic activity, and (b) is one of the mechanisms responsible for motor impairment under certain pathological conditions such as chronic musculoskeletal head-neck disorders, associated with stress conditions.

  1. Localisation of motor areas in brain tumour patients: a comparison of preoperative [{sup 18}F]FDG-PET and intraoperative cortical electrostimulation

    Energy Technology Data Exchange (ETDEWEB)

    Schreckenberger, M.; Sabri, O.; Meyer, P.T.; Zeggel, T.; Zimny, M.; Buell, U. [Technische Univ. Aachen (Germany). Dept. of Nuclear Medicine; Spetzger, U.; Gilsbach, J. [Dept. of Neurosurgery, Aachen Univ. of Technology (Germany)

    2001-09-01

    Assessment of the exact spatial relation between tumour and adjacent functionally relevant brain areas is a primary tool in the presurgical planning in brain tumour patients. The purpose of this study was to compare a preoperative fluorine-18 fluorodeoxyglucose positron emission tomography ([{sup 18}F]FDG PET) activation protocol in patients with tumours near the central area with the results of intraoperative direct cortical electrostimulation, and to determine whether non-invasive preoperative PET imaging can provide results equivalent to those achieved with the invasive neurosurgical ''gold standard''. In this prospective study, we examined 20 patients with various tumours of the central area, performing two PET scans (each 30 min after i.v. injection of 134-341 MBq [{sup 18}F]FDG) in each patient: (1) a resting baseline scan and (2) an activation scan using a standardised motor task (finger tapping, foot stretching). Following PET/MRI realignment and normalisation to the whole brain counts, parametric images of the activation versus the rest study were calculated and pixels above categorical threshold values were projected to the individual MRI for bimodal assessment of morphology and function (PET/MRI overlay). Intraoperative direct cortical electrostimulation was performed using a Viking IV probe (5 pulses, each of 100 {mu}s) and documented using a dedicated neuro navigation system. Results were compared with the preoperative PET findings. PET revealed significant activation of the contralateral primary motor cortex in 95% (19/20) of the brain tumour patients (hand activation 13/13, foot activation 6/7), showing a mean increase in normalised [{sup 18}F]FDG uptake of 20.5%{+-}5.2% (hand activation task) and 17.2%{+-}2.5% (foot activation task). Additionally detected activation of the ipsilateral primary motor cortex was interpreted as a metabolic indication for interhemispheric compensational processes. Evaluation of the PET findings by

  2. Effects of DBS, premotor rTMS, and levodopa on motor function and silent period in advanced Parkinson's disease

    DEFF Research Database (Denmark)

    Bäumer, Tobias; Hidding, Ute; Hamel, Wolfgang

    2009-01-01

    Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a widely used and highly effective treatment for patients with advanced Parkinson's disease (PD). Repetitive TMS (rTMS) applied to motor cortical areas has also been shown to improve symptoms in PD and modulate motor cortical...

  3. Cortical projections to the superior colliculus in tree shrews (Tupaia belangeri).

    Science.gov (United States)

    Baldwin, Mary K L; Wei, Haiyang; Reed, Jamie L; Bickford, Martha E; Petry, Heywood M; Kaas, Jon H

    2013-05-01

    The visuomotor functions of the superior colliculus depend not only on direct inputs from the retina, but also on inputs from neocortex. As mammals vary in the areal organization of neocortex, and in the organization of the number of visual and visuomotor areas, patterns of corticotectal projections vary. Primates in particular have a large number of visual areas projecting to the superior colliculus. As tree shrews are close relatives of primates, and they are also highly visual, we studied the distribution of cortical neurons projecting to the superior colliculus by injecting anatomical tracers into the colliculus. Since projections from visuotopically organized visual areas are expected to match the visuotopy of the superior colliculus, injections at different retinotopic locations in the superior colliculus provide information about the locations and organization of topographic areas in extrastriate cortex. Small injections in the superior colliculus labeled neurons in locations within areas 17 (V1) and 18 (V2) that are consistent with the known topography of these areas and the superior colliculus. In addition, the separate locations of clusters of labeled cells in temporal visual cortex provide evidence for five or more topographically organized areas. Injections that included deeper layers of the superior colliculus also labeled neurons in medial frontal cortex, likely in premotor cortex. Only occasional labeled neurons were observed in somatosensory or auditory cortex. Regardless of tracer injection location, we found that, unlike primates, a substantial projection to the superior colliculus from posterior parietal cortex is not a characteristic of tree shrews.

  4. Self-renewal and differentiation of reactive astrocyte-derived neural stem/progenitor cells isolated from the cortical peri-infarct area after stroke.

    Science.gov (United States)

    Shimada, Issei S; LeComte, Matthew D; Granger, Jerrica C; Quinlan, Noah J; Spees, Jeffrey L

    2012-06-06

    In response to stroke, subpopulations of cortical reactive astrocytes proliferate and express proteins commonly associated with neural stem/progenitor cells such as glial fibrillary acidic protein (GFAP) and Nestin. To examine the stem cell-related properties of cortical reactive astrocytes after injury, we generated GFAP-CreER(TM);tdRFP mice to permanently label reactive astrocytes. We isolated cells from the cortical peri-infarct area 3 d after stroke, and cultured them in neural stem cell medium containing epidermal growth factor and basic fibroblast growth factor. We observed tdRFP-positive neural spheres in culture, suggestive of tdRFP-positive reactive astrocyte-derived neural stem/progenitor cells (Rad-NSCs). Cultured Rad-NSCs self-renewed and differentiated into neurons, astrocytes, and oligodendrocytes. Pharmacological inhibition and conditional knock-out mouse studies showed that Presenilin 1 and Notch 1 controlled neural sphere formation by Rad-NSCs after stroke. To examine the self-renewal and differentiation potential of Rad-NSCs in vivo, Rad-NSCs were transplanted into embryonic, neonatal, and adult mouse brains. Transplanted Rad-NSCs were observed to persist in the subventricular zone and secondary Rad-NSCs were isolated from the host brain 28 d after transplantation. In contrast with neurogenic postnatal day 4 NSCs and adult NSCs from the subventricular zone, transplanted Rad-NSCs differentiated into astrocytes and oligodendrocytes, but not neurons, demonstrating that Rad-NSCs had restricted differentiation in vivo. Our results indicate that Rad-NSCs are unlikely to be suitable for neuronal replacement in the absence of genetic or epigenetic modification.

  5. Microstructure of transcallosal motor fibers reflects type of cortical (re-)organization in congenital hemiparesis.

    Science.gov (United States)

    Juenger, Hendrik; Koerte, Inga K; Muehlmann, Marc; Mayinger, Michael; Mall, Volker; Krägeloh-Mann, Ingeborg; Shenton, Martha E; Berweck, Steffen; Staudt, Martin; Heinen, Florian

    2014-11-01

    Early unilateral brain lesions can lead to different types of corticospinal (re-)organization of motor networks. In one group of patients, the contralesional hemisphere exerts motor control not only over the contralateral non-paretic hand but also over the (ipsilateral) paretic hand, as the primary motor cortex is (re-)organized in the contralesional hemisphere. Another group of patients with early unilateral lesions shows "normal" contralateral motor projections starting in the lesioned hemisphere. We investigated how these different patterns of cortical (re-)organization affect interhemispheric transcallosal connectivity in patients with congenital hemiparesis. Eight patients with ipsilateral motor projections (group IPSI) versus 7 patients with contralateral motor projections (group CONTRA) underwent magnetic resonance diffusion tensor imaging (DTI). The corpus callosum (CC) was subdivided in 5 areas (I-V) in the mid-sagittal slice and volumetric information. The following diffusion parameters were calculated: fractional anisotropy (FA), trace, radial diffusivity (RD), and axial diffusivity (AD). DTI revealed significantly lower FA, increased trace and RD for group IPSI compared to group CONTRA in area III of the corpus callosum, where transcallosal motor fibers cross the CC. In the directly neighboring area IV, where transcallosal somatosensory fibers cross the CC, no differences were found for these DTI parameters between IPSI and CONTRA. Volume of callosal subsections showed significant differences for area II (connecting premotor cortices) and III, where group IPSI had lower volume. The results of this study demonstrate that the callosal microstructure in patients with congenital hemiparesis reflects the type of cortical (re-)organization. Early lesions disrupting corticospinal motor projections to the paretic hand consecutively affect the development or maintenance of transcallosal motor fibers. Copyright © 2014 European Paediatric Neurology Society

  6. Corticospinal neurons in macaque ventral premotor cortex with mirror properties: a potential mechanism for action suppression?

    Science.gov (United States)

    Kraskov, Alexander; Dancause, Numa; Quallo, Marsha M; Shepherd, Samantha; Lemon, Roger N

    2009-12-24

    The discovery of "mirror neurons" in area F5 of the ventral premotor cortex has prompted many theories as to their possible function. However, the identity of mirror neurons remains unknown. Here, we investigated whether identified pyramidal tract neurons (PTNs) in area F5 of two adult macaques exhibited "mirror-like" activity. About half of the 64 PTNs tested showed significant modulation of their activity while monkeys observed precision grip of an object carried out by an experimenter, with somewhat fewer showing modulation during precision grip without an object or grasping concealed from the monkey. Therefore, mirror-like activity can be transmitted directly to the spinal cord via PTNs. A novel finding is that many PTNs (17/64) showed complete suppression of discharge during action observation, while firing actively when the monkey grasped food rewards. We speculate that this suppression of PTN discharge might be involved in the inhibition of self-movement during action observation. 2009 Elsevier Inc. All rights reserved.

  7. Synchrotron X-ray microtransections: a non invasive approach for epileptic seizures arising from eloquent cortical areas

    Science.gov (United States)

    Pouyatos, B.; Nemoz, C.; Chabrol, T.; Potez, M.; Bräuer, E.; Renaud, L.; Pernet-Gallay, K.; Estève, F.; David, O.; Kahane, P.; Laissue, J. A.; Depaulis, A.; Serduc, R.

    2016-06-01

    Synchrotron-generated X-ray (SRX) microbeams deposit high radiation doses to submillimetric targets whilst minimizing irradiation of neighboring healthy tissue. We developed a new radiosurgical method which demonstrably transects cortical brain tissue without affecting adjacent regions. We made such image-guided SRX microtransections in the left somatosensory cortex in a rat model of generalized epilepsy using high radiation doses (820 Gy) in thin (200 μm) parallel slices of tissue. This procedure, targeting the brain volume from which seizures arose, altered the abnormal neuronal activities for at least 9 weeks, as evidenced by a decrease of seizure power and coherence between tissue slices in comparison to the contralateral cortex. The brain tissue located between transections stayed histologically normal, while the irradiated micro-slices remained devoid of myelin and neurons two months after irradiation. This pre-clinical proof of concept highlights the translational potential of non-invasive SRX transections for treating epilepsies that are not eligible for resective surgery.

  8. Different distal-proximal movement balances in right- and left-hand writing may hint at differential premotor cortex involvement.

    Science.gov (United States)

    Potgieser, A R E; de Jong, B M

    2011-12-01

    Right-handed people generally write with their right hand. Language expressed in script is thus performed with the hand also preferred for skilled motor tasks. This may suggest an efficient functional interaction between the language area of Broca and the adjacent ventral premotor cortex (PMv) in the left (dominant) hemisphere. Pilot observations suggested that distal movements are particularly implicated in cursive writing with the right hand and proximal movements in left-hand writing, which generated ideas concerning hemisphere-specific roles of PMv and dorsal premotor cortex (PMd). Now we examined upper-limb movements in 30 right-handed participants during right- and left-hand writing, respectively. Quantitative description of distal and proximal movements demonstrated a significant difference between movements in right- and left-hand writing (pwriting with the right hand, while proximal and distal movements similarly contributed to left-hand writing. Although differences between non-language drawings were not tested, we propose that the DME in right-hand writing may reflect functional dominance of PMv in the left hemisphere. More proximal movements in left-hand writing might be related to PMd dominance in right-hemisphere motor control, logically implicated in spatial visuomotor transformations as seen in reaching.

  9. Cardiovascular physiology in premotor Parkinson's disease: a neuroepidemiologic study.

    Science.gov (United States)

    Jain, Samay; Ton, Thanh G; Perera, Subashan; Zheng, Yan; Stein, Phyllis K; Thacker, Evan; Strotmeyer, Elsa S; Newman, Anne B; Longstreth, Will T

    2012-07-01

    Changes in cardiovascular physiology in Parkinson's disease (PD) are common and may occur prior to diagnostic parkinsonian motor signs. We investigated associations of electrocardiographic (ECG) abnormalities, orthostasis, heart rate variability, and carotid stenosis with the risk of PD diagnosis in the Cardiovascular Health Study, a community-based cohort of older adults. ECG abnormality, orthostasis (symptomatic or asymptomatic), heart rate variability (24-hour Holter monitoring), and any carotid stenosis (≥1%) by ultrasound were modeled as primary predictors of incident PD diagnosis using multivariable logistic regression. Incident PD cases were identified by at least 1 of the following: self-report, antiparkinsonian medication use, and ICD-9. If unadjusted models were significant, they were adjusted or stratified by age, sex, and smoking status, and those in which predictors were still significant (P ≤ .05) were also adjusted for race, diabetes, total cholesterol, low-density lipoprotein, blood pressure, body mass index, physical activity, education level, stroke, and C-reactive protein. Of 5888 participants, 154 incident PD cases were identified over 14 years of follow-up. After adjusting models with all covariates, those with any ECG abnormality (odds ratio [OR], 1.45; 95% CI, 1.02-2.07; P = .04) or any carotid stenosis (OR, 2.40; 95% CI, 1.40-4.09; P = .001) at baseline had a higher risk of incident PD diagnosis. Orthostasis and heart rate variability were not significant predictors. This exploratory study suggests that carotid stenosis and ECG abnormalities occur prior to motor signs in PD, thus serving as potential premotor features or risk factors for PD diagnosis. Replication is needed in a population with more thorough ascertainment of PD onset.

  10. Writer's cramp: increased dorsal premotor activity during intended writing.

    Science.gov (United States)

    Delnooz, Cathérine C S; Helmich, Rick C; Medendorp, W P; Van de Warrenburg, Bart P C; Toni, Ivan

    2013-03-01

    Simple writer's cramp (WC) is a task-specific form of dystonia, characterized by abnormal movements and postures of the hand during writing. It is extremely task-specific, since dystonic symptoms can occur when a patient uses a pencil for writing, but not when it is used for sharpening. Maladaptive plasticity, loss of inhibition, and abnormal sensory processing are important pathophysiological elements of WC. However, it remains unclear how those elements can account for its task-specificity. We used fMRI to isolate cerebral alterations associated with the task-specificity of simple WC. Subjects (13 simple WC patients, 20 matched controls) imagined grasping a pencil to either write with it or sharpen it. On each trial, we manipulated the pencil's position and the number of imagined movements, while monitoring variations in motor output with electromyography. We show that simple WC is characterized by abnormally increased activity in the dorsal premotor cortex (PMd) when imagined actions are specifically related to writing. This cerebral effect was independent from the known deficits in dystonia in generating focal motor output and in processing somatosensory feedback. This abnormal activity of the PMd suggests that the task-specific element of simple WC is primarily due to alterations at the planning level, in the computations that transform a desired action outcome into the motor commands leading to that action. These findings open the way for testing the therapeutic value of interventions that take into account the computational substrate of task-specificity in simple WC, e.g. modulations of PMd activity during the planning phase of writing.

  11. Analysis of Cortical Flow Models In Vivo

    Science.gov (United States)

    Benink, Hélène A.; Mandato, Craig A.; Bement, William M.

    2000-01-01

    Cortical flow, the directed movement of cortical F-actin and cortical organelles, is a basic cellular motility process. Microtubules are thought to somehow direct cortical flow, but whether they do so by stimulating or inhibiting contraction of the cortical actin cytoskeleton is the subject of debate. Treatment of Xenopus oocytes with phorbol 12-myristate 13-acetate (PMA) triggers cortical flow toward the animal pole of the oocyte; this flow is suppressed by microtubules. To determine how this suppression occurs and whether it can control the direction of cortical flow, oocytes were subjected to localized manipulation of either the contractile stimulus (PMA) or microtubules. Localized PMA application resulted in redirection of cortical flow toward the site of application, as judged by movement of cortical pigment granules, cortical F-actin, and cortical myosin-2A. Such redirected flow was accelerated by microtubule depolymerization, showing that the suppression of cortical flow by microtubules is independent of the direction of flow. Direct observation of cortical F-actin by time-lapse confocal analysis in combination with photobleaching showed that cortical flow is driven by contraction of the cortical F-actin network and that microtubules suppress this contraction. The oocyte germinal vesicle serves as a microtubule organizing center in Xenopus oocytes; experimental displacement of the germinal vesicle toward the animal pole resulted in localized flow away from the animal pole. The results show that 1) cortical flow is directed toward areas of localized contraction of the cortical F-actin cytoskeleton; 2) microtubules suppress cortical flow by inhibiting contraction of the cortical F-actin cytoskeleton; and 3) localized, microtubule-dependent suppression of actomyosin-based contraction can control the direction of cortical flow. We discuss these findings in light of current models of cortical flow. PMID:10930453

  12. Focal cortical dysplasia - review.

    Science.gov (United States)

    Kabat, Joanna; Król, Przemysław

    2012-04-01

    Focal cortical dysplasia is a malformation of cortical development, which is the most common cause of medically refractory epilepsy in the pediatric population and the second/third most common etiology of medically intractable seizures in adults.Both genetic and acquired factors are involved in the pathogenesis of cortical dysplasia. Numerous classifications of the complex structural abnormalities of focal cortical dysplasia have been proposed - from Taylor et al. in 1971 to the last modification of Palmini classification made by Blumcke in 2011. In general, three types of cortical dysplasia are recognized.Type I focal cortical dysplasia with mild symptomatic expression and late onset, is more often seen in adults, with changes present in the temporal lobe.Clinical symptoms are more severe in type II of cortical dysplasia usually seen in children. In this type, more extensive changes occur outside the temporal lobe with predilection for the frontal lobes.New type III is one of the above dysplasias with associated another principal lesion as hippocampal sclerosis, tumor, vascular malformation or acquired pathology during early life.Brain MRI imaging shows abnormalities in the majority of type II dysplasias and in only some of type I cortical dysplasias.THE MOST COMMON FINDINGS ON MRI IMAGING INCLUDE: focal cortical thickening or thinning, areas of focal brain atrophy, blurring of the gray-white junction, increased signal on T2- and FLAIR-weighted images in the gray and subcortical white matter often tapering toward the ventricle. On the basis of the MRI findings, it is possible to differentiate between type I and type II cortical dysplasia. A complete resection of the epileptogenic zone is required for seizure-free life. MRI imaging is very helpful to identify those patients who are likely to benefit from surgical treatment in a group of patients with drug-resistant epilepsy.However, in type I cortical dysplasia, MR imaging is often normal, and also in both types

  13. α-Synuclein in the colon and premotor markers of Parkinson disease in neurologically normal subjects.

    Science.gov (United States)

    Kim, Joong-Seok; Park, In-Seok; Park, Hyung-Eun; Kim, Su-Young; Yun, Jung A; Jung, Chan Kwon; Sung, Hye-Young; Lee, Jin-Kwon; Kang, Won-Kyung

    2017-01-01

    Extranigral non-motor signs precede the first motor manifestations of Parkinson's disease by many years in some patients. The presence of α-synuclein deposition within colon tissues in patients with Parkinson's disease can aid in identifying early neuropathological changes prior to disease onset. In the present study, we evaluated the roles of non-motor symptoms and signs and imaging biomarkers of nigral neuronal changes and α-synuclein accumulation in the colon. Twelve subjects undergoing colectomy for primary colon cancer were recruited for this study. Immunohistochemical staining for α-synuclein in normal and phosphorylated forms was performed in normally appearing colonic tissue. We evaluated 16 candidate premotor risk factors in this study cohort. Among them, ten subjects showed positive immunostaining with normal- and phosphorylated-α-synuclein. An accumulation of premotor markers in each subject was accompanied with positive normal- and phosphorylated-α-synuclein immunostaining, ranging from 2 to 7 markers per subject, whereas the absence of Lewy bodies in the colon was associated with relative low numbers of premotor signs. A principal component analysis and a cluster analysis of these premotor markers suggest that urinary symptoms were commonly clustered with deposition of peripheral phosphorylated-α-synuclein. Among other premotor marker, color vision abnormalities were related to non-smoking. This mathematical approach confirmed the clustering of premotor markers in preclinical stage of Parkinson's disease. This is the first report showing that α-synuclein in the colon and other premotor markers are related to each other in neurologically normal subjects.

  14. Alpha- and theta-range cortical synchronization and corticomuscular coherence during joystick manipulation in a virtual navigation task.

    Science.gov (United States)

    Hori, Satoshi; Matsumoto, Jumpei; Hori, Etsuro; Kuwayama, Naoya; Ono, Taketoshi; Kuroda, Satoshi; Nishijo, Hisao

    2013-10-01

    Previous studies have reported that multiple brain regions are activated during spatial navigation, but it remains unclear how this activation is converted to motor commands for navigation. This study was aimed to investigate synchronization across different brain regions and between cortical areas and muscles during spatial navigation. This synchronization has been suggested to be essential for integrating activity in the multiple brain areas to support higher cognitive functions and for conversion of cortical activity to motor commands. In the present study, the subjects were required to sequentially trace ten checkpoints in a virtual town by manipulating a joystick and to perform this three times while electroencephalograms and electromyograms from the right arm were monitored. Time spent on the task in the third trial was significantly lesser than that in the first trial indicating an improvement in task performance. This repeated learning was associated with an increase in alpha power at the electrodes over the contralateral sensorimotor region and in theta power at the electrodes over the bilateral premotor and frontotemporal regions. Alpha- and theta-range corticocortical coherences between these regions and other brain areas were also increased in the third trial compared to the first trial. Furthermore, alpha- and theta-range corticomuscular coherence was significantly increased in the second and third trials compared to the first trial. These results suggest that alpha- and theta-range synchronous activity across multiple systems is essential for the integrated brain activity required in spatial navigation and for the conversion of this activity to motor commands.

  15. Distribution and network of basal temporal language areas: a study of the combination of electric cortical stimulation and diffusion tensor imaging.

    Science.gov (United States)

    Enatsu, Rei; Kanno, Aya; Ookawa, Satoshi; Ochi, Satoko; Ishiai, Sumio; Nagamine, Takashi; Mikuni, Nobuhiro

    2017-06-21

    The basal temporal language area (BTLA) is considered to have several functions in language processing; however, its brain network is still unknown. This study investigated the distribution and networks of the BTLA using a combination of electric cortical stimulation and diffusion tensor imaging (DTI). Ten patients with intractable focal epilepsy who underwent presurgical evaluation with subdural electrodes were enrolled in this study (language dominant side: six patients, language non-dominant side: four patients). Electric stimulation at 50 Hz was applied to the electrodes during Japanese sentence reading, morphograms (kanji) reading, and syllabograms (kana) reading tasks to identify the BTLA. DTI was used to identify the subcortical fibers originating from the BTLA found by electrical stimulation. The BTLA was found in six patients who underwent implantation of the subdural electrodes in the dominant hemisphere. The BTLA was located anywhere between 20-56 mm posterior to temporal tips. In three patients, electrical stimulation of some or all areas within the BTLA induced disturbance in reading of kanji words only. DTI detected the inferior longitudinal fasciculus (ILF) in all patients and the uncinate fasciculus (UF) in one patient, originating from the BTLA. ILF was detected from both kanji-specific areas and kanji-nonspecific areas. This study indicates that the network of the BTLA is a part of a ventral stream, and is mainly composed of the ILF, which acts as a critical structure for lexical retrieval. ILF is also associated with the specific process of kanji words. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Spatial and viewpoint selectivity for others' observed actions in monkey ventral premotor mirror neurons.

    Science.gov (United States)

    Maranesi, Monica; Livi, Alessandro; Bonini, Luca

    2017-08-15

    The spatial location and viewpoint of observed actions are closely linked in natural social settings. For example, actions observed from a subjective viewpoint necessarily occur within the observer's peripersonal space. Neurophysiological studies have shown that mirror neurons (MNs) of the monkey ventral premotor area F5 can code the spatial location of live observed actions. Furthermore, F5 MN discharge can also be modulated by the viewpoint from which filmed actions are seen. Nonetheless, whether and to what extent MNs can integrate viewpoint and spatial location of live observed actions remains unknown. We addressed this issue by comparing the activity of 148 F5 MNs while macaque monkeys observed an experimenter grasping in three different combinations of viewpoint and spatial location, namely, lateral view in the (1) extrapersonal and (2) peripersonal space and (3) subjective view in the peripersonal space. We found that the majority of MNs were space-selective (60.8%): those selective for the peripersonal space exhibited a preference for the subjective viewpoint both at the single-neuron and population level, whereas space-unselective neurons were view invariant. These findings reveal the existence of a previously neglected link between spatial and viewpoint selectivity in MN activity during live-action observation.

  17. A setup for administering TMS to medial and lateral cortical areas during whole-brain FMRI recording

    NARCIS (Netherlands)

    Weijer, A.D. de; Sommer, I.E.C.; Bakker, E.J.; Bloemendaal, M.; Bakker, C.J.; Klomp, D.W.J.; Bestmann, S.; Neggers, S.F.W.

    2014-01-01

    SUMMARY: Stimulating brain areas with transcranial magnetic stimulation (TMS) while concurrently and noninvasively recording brain activity changes through functional MRI enables a new range of investigations about causal interregional interactions in the human brain. However, standard head-coil arr

  18. The importance of premotor cortex for supporting speech production after left capsular-putaminal damage.

    Science.gov (United States)

    Seghier, Mohamed L; Bagdasaryan, Juliana; Jung, Dorit E; Price, Cathy J

    2014-10-22

    The left putamen is known to be important for speech production, but some patients with left putamen damage can produce speech remarkably well. We investigated the neural mechanisms that support this recovery by using a combination of techniques to identify the neural regions and pathways that compensate for loss of the left putamen during speech production. First, we used fMRI to identify the brain regions that were activated during reading aloud and picture naming in a patient with left putamen damage. This revealed that the patient had abnormally high activity in the left premotor cortex. Second, we used dynamic causal modeling of the patient's fMRI data to understand how this premotor activity influenced other speech production regions and whether the same neural pathway was used by our 24 neurologically normal control subjects. Third, we validated the compensatory relationship between putamen and premotor cortex by showing, in the control subjects, that lower connectivity through the putamen increased connectivity through premotor cortex. Finally, in a lesion-deficit analysis, we demonstrate the explanatory power of our fMRI results in new patients who had damage to the left putamen, left premotor cortex, or both. Those with damage to both had worse reading and naming scores. The results of our four-pronged approach therefore have clinical implications for predicting which patients are more or less likely to recover their speech after left putaminal damage. Copyright © 2014 Seghier et al.

  19. Cortico-cortical communication dynamics

    Directory of Open Access Journals (Sweden)

    Per E Roland

    2014-05-01

    Full Text Available IIn principle, cortico-cortical communication dynamics is simple: neurons in one cortical area communicate by sending action potentials that release glutamate and excite their target neurons in other cortical areas. In practice, knowledge about cortico-cortical communication dynamics is minute. One reason is that no current technique can capture the fast spatio-temporal cortico-cortical evolution of action potential transmission and membrane conductances with sufficient spatial resolution. A combination of optogenetics and monosynaptic tracing with virus can reveal the spatio-temporal cortico-cortical dynamics of specific neurons and their targets, but does not reveal how the dynamics evolves under natural conditions. Spontaneous ongoing action potentials also spread across cortical areas and are difficult to separate from structured evoked and intrinsic brain activity such as thinking. At a certain state of evolution, the dynamics may engage larger populations of neurons to drive the brain to decisions, percepts and behaviors. For example, successfully evolving dynamics to sensory transients can appear at the mesoscopic scale revealing how the transient is perceived. As a consequence of these methodological and conceptual difficulties, studies in this field comprise a wide range of computational models, large-scale measurements (e.g., by MEG, EEG, and a combination of invasive measurements in animal experiments. Further obstacles and challenges of studying cortico-cortical communication dynamics are outlined in this critical review.

  20. When does this cortical area drop off? Principal component structuring of the EEG spectrum yields yes-or-no criteria of local sleep onset.

    Science.gov (United States)

    Putilov, Arcady A

    2014-06-22

    The traditional sleep scoring approach has been invented long before the recognition of strictly local nature of the sleep process. It considers sleep as a whole-organism behavior state, and, thus, it cannot be used for identification of sleep onset in a separate brain region. Therefore, this paper was aimed on testing whether the practically useful, simple and reliable yes-or-no criterion of sleep onset in a particular cortical region might be developed through applying principal component analysis to the electroencephalographic (EEG) spectra. The resting EEG was recorded with 2-hour intervals throughout 43-61-hour prolongation of wakefulness, and during 12 20-minute attempts to nap in the course of 24-hour wakefulness (15 and 18 adults, respectively). The EEG power spectra were averaged on 1-min intervals of each resting EEG record and on 1-min intervals of each napping attempt, respectively. Since we earlier demonstrated that scores on the first and second principal components of the EEG spectrum exhibit dramatic changes during the sleep onset period, a zero-crossing buildup of the first score and a zero-crossing decline of the second score were examined as possible yes-or-no markers of regional sleep onsets. The results suggest that, irrespective of electrode location, sleep onset criterion and duration of preceding wakefulness, a highly significant zero-crossing decline of the second principal component score always occurred within 1-minute interval of transition from wakefulness to sleep. Therefore, it was concluded that such zero-crossing decline can serve as a reliable, simple, and practically useful yes-or-no marker of drop off event in a given cortical area.

  1. Enhancing motor network activity using real-time functional MRI neurofeedback of left premotor cortex

    Directory of Open Access Journals (Sweden)

    Theo Ferreira Marins

    2015-12-01

    Full Text Available Neurofeedback by functional Magnetic Resonance Imaging (fMRI is a technique of potential therapeutic relevance that allows individuals to be aware of their own neurophysiological responses and to voluntarily modulate the activity of specific brain regions, such as the premotor cortex (PMC, important for motor recovery after brain injury. We investigated (i whether healthy human volunteers are able to up-regulate the activity of the left PMC during a right hand finger tapping motor imagery (MI task while receiving continuous fMRI-neurofeedback, and (ii whether successful modulation of brain activity influenced non-targeted motor control regions. During the MI task, participants of the neurofeedback group (NFB received ongoing visual feedback representing the level of fMRI responses within their left PMC. Control (CTL group participants were shown similar visual stimuli, but these were non-contingent on brain activity. Both groups showed equivalent levels of behavioral ratings on arousal and motor imagery, before and during the fMRI protocol. In the NFB, but not in CLT group, brain activation during the last run compared to the first run revealed increased activation in the left PMC. In addition, the NFB group showed increased activation in motor control regions extending beyond the left PMC target area, including the supplementary motor area, basal ganglia and cerebellum. Moreover, in the last run, the NFB group showed stronger activation in the left PMC/inferior frontal gyrus when compared to the CTL group. Our results indicate that modulation of PMC and associated motor control areas can be achieved during a single neurofeedback-fMRI session. These results contribute to a better understanding of the underlying mechanisms of MI-based neurofeedback training, with direct implications for rehabilitation strategies in severe brain disorders, such as stroke.

  2. Localization of the cortical motor area by functional magnetic resonance imaging with gradient echo and echo-planar methods, using clinical 1.5 Tesla MR imaging systems.

    Science.gov (United States)

    Nakayama, K

    1997-06-01

    Functional magnetic resonance imaging (MRI) with gradient echo and echo-planar sequences was applied to healthy volunteers and neurological patients to evaluate the feasibility of detecting and localizing the motor cortex. Time course of the change in signal intensity by an alternate repetition of motor task (squeezing hand) and rest periods was also examined. The motor cortex was localized as the area of signal increase in 88.9% of 45 healthy volunteers by gradient echo method, which mainly reflected the cortical vein, and 83.3% of 30 healthy volunteers by echo-planar method, which mainly reflected the cerebral gyrus. Among 21 volunteers who participated in the both studies, success rate in the localization for the motor cortex was 90.5% (21 volunteers) by gradient echo method and 81% (17 volunteers) by echo-planar method. It was also shown from the time course of the change in signal intensity that signal increase in the most significantly activated area generally corresponded with the periods of the motor task, and the latency between the onset of signal increase and the onset of motor task was usually about 4 seconds. In four of 6 patients with brain tumor, the motor cortex was localized, although activated areas were displaced or distorted. The results indicate that fMRI, either with gradient echo or echo-planar sequence, is a useful method for localizing the primary motor area activated during the motor task and clinically available for noninvasive evaluation of the anatomical relation between brain tumors and the motor area before surgical therapy.

  3. 足三里等下肢穴位刺激引发脑运动皮质去激活效应的fMRI研究%Using fMRI to Explore Deactivation in Motor Cortices after Zusanli,Yinlingquan,Fenglong,Sanyinjiao Acupoint Stimulation

    Institute of Scientific and Technical Information of China (English)

    魏鹏绪; 鲍瑞雪; 张通; 李坤成; 卢洁; 赵澄

    2011-01-01

    Objectives: To investigate the deactivation responses of individual areas in the human left primary motor cortices, premotor areas and supplementary motor areas to stimulating acupoints Zusanli, Yinlingquan, Fenglong, Sanyinjiao of right body - side. Methods: Ten male healthy subjects received functional MRI examination in a 3T Siemens MAGNETOM Trio system with a block - designed method. BOLD weighted functional images were acquired in the axial plane.Data were analyzed with SPM5 software package to acquire magnitudes of BOLD signal changes with 1st level Bayesian inference. Results: Deactivated signals were found in left primary motor cortices, premotor areas and supplementary motor areas when stimulating each acupoint for every subjets. For Zusanli stimulation, activated signals were found within left primary motor cortices from eight people out of the ten subjects, and within left premotor areas and supplementary motor areas from nine people out of the ten subjects. For Yinlingquan stimulation, activated signals were found within left primary motor cortices and within left premotor areas and supplementary motor areas from all ten subjects. For Fenglong stimulation, activated signals were found within left primary motor cortices from nine people out of the ten subjects, and within left premotor areas and supplementary motor areas from nine people out of the ten subjects. For Sanyinjiao stimulation, activated signals were found within left primary motor cortices from nine people out of the ten subjects, and within left premotor areas and supplementary motor areas from all ten subjects. Conclusion: Znsanli, Yinlingquan, Fenglong or Sanyinjiao stimulation can activate contralateral primary motor cortices, premotor areas and supplementary motor areas for most subjects. However, deactivation can be seen in every condition from each subject. This phenomenon suggests that the effects of acupoint stimulation on central nervous system involve not only activation but

  4. Synaptic properties of thalamic and intracortical inputs to layer 4 of the first- and higher-order cortical areas in the auditory and somatosensory systems.

    Science.gov (United States)

    Lee, Charles C; Sherman, S Murray

    2008-07-01

    The thalamus is an essential structure in the mammalian forebrain conveying information topographically from the sensory periphery to primary neocortical areas. Beyond this initial processing stage, "higher-order" thalamocortical connections have been presumed to serve only a modulatory role, or are otherwise functionally disregarded. Here we demonstrate that these "higher-order" thalamic nuclei share similar synaptic properties with the "first-order" thalamic nuclei. Using whole cell recordings from layer 4 neurons in thalamocortical slice preparations in the mouse somatosensory and auditory systems, we found that electrical stimulation in all thalamic nuclei elicited large, glutamatergic excitatory postsynaptic potentials (EPSPs) that depress in response to repetitive stimulation and that fail to activate a metabotropic glutamate response. In contrast, the intracortical inputs from layer 6 to layer 4 exhibit facilitating EPSPs. These data suggest that higher-order thalamocortical projections may serve a functional role similar to the first-order nuclei, whereas both are physiologically distinct from the intracortical layer 6 inputs. These results suggest an alternate route for information transfer between cortical areas via a corticothalamocortical pathway.

  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. Recognition and imitation of pantomimed motor acts after unilateral parietal and premotor lesions: a perspective on apraxia.

    Science.gov (United States)

    Halsband, U; Schmitt, J; Weyers, M; Binkofski, F; Grützner, G; Freund, H J

    2001-01-01

    We compared gesture comprehension and imitation in patients with lesions in the left parietal lobe (LPAR, n=5) and premotor cortex/supplementary motor area (LPMA, n=8) in patients with damage to the right parietal lobe (RPAR, n=6) and right premotor/supplementary motor area (RPMA, n=6) and in 16 non-brain damaged control subjects. Three patients with left parietal lobe damage had aphasia. Subjects were shown 136 meaningful pantomimed motor acts on a videoscreen and were asked to identify the movements and to imitate the motor acts from memory with their ipsilesional and contralesional hand or with both hands simultaneously. Motor tasks included gestures without object use (e.g. to salute, to wave) pantomimed imitation of gestures on one's own body (e.g. to comb one's hair) and pantomimed imitation of motor acts which imply tool use to an object in extrapersonal space (e.g. to hammer a nail). Videotaped test performance was analysed by two independent raters; errors were classified as spatial errors, body part as object, parapraxic performance and non-identifiable movements. In addition, action discrimination was tested by evaluating whether a complex motor sequence was correctly performed. Results indicate that LPAR patients were most severely disturbed when imitation performance was assessed. Interestingly, LPAR patients were worse when imitating gestures on their own bodies than imitating movements with reference to an external object use with most pronounced deficits in the spatial domain. In contrast to imitation, comprehension was not or only slightly disturbed and no clear correlation was found between the severity of imitation deficits and gesture comprehension. Moreover, although the three patients with aphasia imitated the movements more poorly than non-aphasic LPAR patients, the severity of comprehension errors did not differ. Whereas unimanual imitating performance and gesture comprehension of PMA patients did not differ significantly from control

  7. In vivo optogenetic tracing of functional corticocortical connections between motor forelimb areas

    Directory of Open Access Journals (Sweden)

    Riichiro eHira

    2013-04-01

    Full Text Available Interactions between distinct motor cortical areas are essential for coordinated motor behaviors. In rodents, the motor cortical forelimb areas are divided into at least two distinct areas: the rostral forelimb area (RFA and the caudal forelimb area (CFA. The RFA is thought to be an equivalent of the premotor cortex in primates, whereas the CFA is believed to be an equivalent of the primary motor cortex. Although reciprocal connections between the RFA and the CFA have been anatomically identified in rats, it is unknown whether there are functional connections between these areas that can induce postsynaptic spikes. In this study, we used an in vivo Channelrhodopsin-2 photostimulation method to trace the functional connections between the mouse RFA and CFA. Simultaneous electrical recordings were utilized to detect spiking activities induced by synaptic inputs originating from photostimulated areas. This method, in combination with anatomical tracing, demonstrated that the RFA receives strong functional projections from layer 2/3 and/or layer 5a, but not from layer 5b, of the CFA. Further, the CFA receives strong projections from layer 5b neurons of the RFA. The onset latency of electrical responses evoked in remote areas upon photostimulation of the other areas was approximately 10 ms, which is consistent with the synaptic connectivity between these areas. Our results suggest that neuronal activities in the RFA and the CFA during movements are formed through asymmetric reciprocal connections.

  8. The human premotor oculomotor brainstem system - can it help to understand oculomotor symptoms in Huntington's disease?

    NARCIS (Netherlands)

    Rueb, U.; Heinsen, H.; Brunt, E. R.; Landwehrmeyer, B.; Den Dunnen, W. F. A.; Gierga, K.; Deller, T.

    2009-01-01

    Recent progress in oculomotor research has enabled new insights into the functional neuroanatomy of the human premotor oculomotor brainstem network. In the present review, we provide an overview of its functional neuroanatomy and summarize the broad range of oculomotor dysfunctions that may occur in

  9. Charting the excitability of premotor to motor connections while withholding or initiating a selected movement

    DEFF Research Database (Denmark)

    Kroeger, Johan; Bäumer, Tobias; Jonas, Melanie

    2010-01-01

    In 19 healthy volunteers, we used transcranial magnetic stimulation (TMS) to probe the excitability in pathways linking the left dorsal premotor cortex and right primary motor cortex and those linking the left and right motor cortex during the response delay and the reaction time period while sub...

  10. Continuous Theta-Burst Stimulation Demonstrates a Causal Role of Premotor Homunculus in Action Understanding

    DEFF Research Database (Denmark)

    Michael, John; Sandberg, Kristian; Skewes, Joshua

    2014-01-01

    Although it is well established that regions of premotor cortex (PMC) are active during action observation, it remains controversial whether they play a causal role in action understanding. In the experiment reported here, we used offline continuous theta-burst stimulation (cTBS) to investigate...

  11. 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-handed ...

  12. Continuous Theta-Burst Stimulation Demonstrates a Causal Role of Premotor Homunculus in Action Understanding

    DEFF Research Database (Denmark)

    Michael, John; Sandberg, Kristian; Skewes, Joshua

    2014-01-01

    Although it is well established that regions of premotor cortex (PMC) are active during action observation, it remains controversial whether they play a causal role in action understanding. In the experiment reported here, we used offline continuous theta-burst stimulation (cTBS) to investigate t...

  13. Low-frequency transcranial magnetic stimulation over left dorsal premotor cortex improves the dynamic control of visuospatially cued actions

    Science.gov (United States)

    Ward, Nick S.; Bestmann, Sven; Hartwigsen, Gesa; Weiss, Michael M.; Christensen, Lars O.D.; Frackowiak, Richard S.J.; Rothwell, John C.; Siebner, Hartwig R.

    2013-01-01

    Left rostral dorsal premotor cortex (rPMd) and supramarginal gyrus (SMG) have been implicated in the dynamic control of actions. In 12 right-handed healthy individuals we applied 30 minutes of low-frequency (1Hz) repetitive transcranial magnetic stimulation (rTMS) over left rPMd to investigate the involvement of left rPMd and SMG in the rapid adjustment of actions guided by visuospatial cues. After rTMS, subjects underwent functional magnetic resonance imaging while making spatially congruent button presses with right or left index finger in response to a left- or right-sided target. Subjects were asked to covertly prepare motor responses as indicated by a directional cue presented one second before the target. On 20% of trials the cue was invalid requiring subjects to re-adjust their motor plan according to the target location. Compared to sham rTMS, real rTMS increased the number of correct responses in invalidly cued trials. After real rTMS, task-related activity of the stimulated left rPMd showed increased task-related coupling with activity in ipsilateral SMG and adjacent anterior intraparietal area (AIP). Individuals who showed a stronger increase in left-hemispheric premotor-parietal connectivity also made fewer errors on invalidly cued trials after rTMS. The results suggest that rTMS over left rPMd improved the ability to dynamically adjust visuospatial response mapping by strengthening left-hemispheric connectivity between rPMd and the SMG-AIP region. These results support the notion that left rPMd and SMG-AIP contribute towards dynamic control of actions, and demonstrate that low-frequency rTMS can enhance functional coupling between task-relevant brain regions and improve some aspects of motor performance. PMID:20610756

  14. Movement-related cortical activation with voluntary pinch task: simultaneous monitoring of near-infrared spectroscopy signals and movement-related cortical potentials

    Science.gov (United States)

    Sato, Yosuke; Fukuda, Masafumi; Oishi, Makoto; Fujii, Yukihiko

    2012-07-01

    This study was designed to evaluate hemodynamic and electrophysiological motor cortex responses to voluntary finger pinching in humans, with simultaneous recording of near-infrared spectroscopy (NIRS) signals and movement-related cortical potentials (MRCP). Six healthy, right-handed subjects performed 100 trials of voluntary right-thumb index-finger pinching with about a 10-second interval at their own pace. Throughout the session, 48 regions over the bilateral motor cortex were assessed by NIRS, while MRCP and electromyogram (EMG) were simultaneously monitored. MRCP started 1536+/-58 ms before EMG onset and peaked 127+/-24 ms after EMG onset. NIRS data showed bilateral prefrontal cortex at 0.5+/-0.1 s before EMG onset and bilateral dorsal premotor cortex activations at 0.6+/-0.1 s before EMG onset. The hand area of the sensorimotor cortex was activated left-dominantly, seen obviously peaked at 3.7+/-0.2 s after EMG onset. The comparison between MRCP and NIRS results raised the possibility that the vascular response to neural activity occurs within 4 s with a voluntary pinch task. These results indicate that our technique allows detailed study of the motor control. Our method is a promising strategy for event-related motor control and neurovascular coupling studies.

  15. Early Changes of the Cortical Micro-Channel System in the Bare Area of the Joints of Patients With Rheumatoid Arthritis.

    Science.gov (United States)

    Werner, David; Simon, David; Englbrecht, Matthias; Stemmler, Fabian; Simon, Christoph; Berlin, Andreas; Haschka, Judith; Renner, Nina; Buder, Thomas; Engelke, Klaus; Hueber, Axel J; Rech, Jürgen; Schett, Georg; Kleyer, Arnd

    2017-08-01

    To characterize the specific structural properties of the erosion-prone bare area of the human joint, and to search for early microstructural changes in this region during rheumatoid arthritis (RA). In the initial part of the study, human cadaveric hand joints were examined for exact localization of the bare area of the metacarpal heads, followed by detection of cortical micro-channels (CoMiCs) in this region by high-resolution peripheral quantitative computed tomography (HR-pQCT) and, after anatomic dissection, validation of the presence of CoMiCs by micro-computed tomography (micro-CT). In the second part of the study, the number and distribution of CoMiCs were analyzed in 107 RA patients compared to 105 healthy individuals of similar age and sex distribution. Investigation by HR-pQCT combined with adaptive thresholding allowed the detection of CoMiCs in the bare area of human cadaveric joints. The existence of CoMiCs in the bare area was additionally validated by micro-CT. In healthy individuals, the number of CoMiCs increased with age. RA patients showed significantly more CoMiCs compared to healthy individuals (mean ± SD 112.9 ± 54.7/joint versus 75.2 ± 41.9/joint; P CoMiCs as observed in healthy individuals older than age 65 years. Importantly, CoMiCs were already found in RA patients very early in their disease course, with enrichment in the erosion-prone radial side of the joint. CoMiCs represent a new form of structural change in the joints of patients with RA. Although the number of CoMiCs increases with age, RA patients develop CoMiCs much earlier in life, and such changes can even occur at the onset of the disease. CoMiCs therefore represent an interesting new opportunity to assess structural changes in RA. © 2017, American College of Rheumatology.

  16. Increased Intrinsic Activity of Medial-Temporal Lobe Subregions is Associated with Decreased Cortical Thickness of Medial-Parietal Areas in Patients with Alzheimer's Disease Dementia.

    Science.gov (United States)

    Pasquini, Lorenzo; Scherr, Martin; Tahmasian, Masoud; Myers, Nicholas E; Ortner, Marion; Kurz, Alexander; Förstl, Hans; Zimmer, Claus; Grimmer, Timo; Akhrif, Atae; Wohlschläger, Afra M; Riedl, Valentin; Sorg, Christian

    2016-01-01

    In Alzheimer's disease (AD), disrupted connectivity between medial-parietal cortices and medial-temporal lobes (MTL) is linked with increased MTL local functional connectivity, and parietal atrophy is associated with increased MTL memory activation. We hypothesized that intrinsic activity in MTL subregions is increased and associated with medial-parietal degeneration and impaired memory in AD. To test this hypothesis, resting-state-functional and structural-MRI was assessed in 22 healthy controls, 22 mild cognitive impairment patients, and 21 AD-dementia patients. Intrinsic activity was measured by power-spectrum density of blood-oxygenation-level-dependent signal, medial-parietal degeneration by cortical thinning. In AD-dementia patients, intrinsic activity was increased for several right MTL subregions. Raised intrinsic activity in dentate gyrus and cornu ammonis 1 was associated with cortical thinning in posterior cingulate cortices, and at-trend with impaired delayed recall. Critically, increased intrinsic activity in the right entorhinal cortex was associated with ipsilateral posterior cingulate degeneration. Our results provide evidence that in AD, intrinsic activity in MTL subregions is increased and associated with medial-parietal atrophy. Results fit a model in which medial-parietal degeneration contributes to MTL dysconnectivity from medial-parietal cortices, potentially underpinning disinhibition-like changes in MTL activity.

  17. Cortical Visual Impairment

    Science.gov (United States)

    ... Frequently Asked Questions Español Condiciones Chinese Conditions Cortical Visual Impairment En Español Read in Chinese What is cortical visual impairment? Cortical visual impairment (CVI) is a decreased visual ...

  18. Electro-acupuncture exerts beneficial effects against cerebral ischemia and promotes the proliferation of neural progenitor cells in the cortical peri-infarct area through the Wnt/β-catenin signaling pathway.

    Science.gov (United States)

    Chen, Bin; Tao, Jing; Lin, Yukun; Lin, Ruhui; Liu, Weilin; Chen, Lidian

    2015-11-01

    Electro-acupuncture (EA) is a novel therapy based on combining traditional acupuncture with modern electrotherapy, and it is currently being investigated as a treatment for ischemic stroke. In the present study, we aimed to investigate the mechanisms through which EA regulates the proliferation of neural progenitor cells (NPCs) in the cortical peri‑infarct area after stroke. The neuroprotective effects of EA on ischemic rats were evaluated by determining the neurological deficit scores and cerebral infarct volumes. The proliferation of the NPCs and the activation of the Wnt/β‑catenin signaling pathway in the cortical peri‑infarct area were examined. Our results revealed that EA significantly alleviated neurological deficits, reduced the infarct volume and enhanced NPC proliferation [nestin/glial fibrillary acidic protein (GFAP)‑double positive] in the cortex of rats subjected to middle cerebral artery occlusion (MCAO). Moreover, the Wnt1 and β‑catenin mRNA and protein levels were increased, while glycogen synthase kinase‑3 (GSK3) transcription was suppressed by EA. These results suggest that the upregulatory effects of EA on the Wnt/β‑catenin signaling pathway may promote NPC proliferation in the cortical peri-infarct area after stroke, consequently providing a therapeutic effect against cerebral ischemia.

  19. Application of cortical mapping in the surgical treatment of brain tumors in language areas%皮层功能制图在语言功能区脑肿瘤手术治疗中的应用

    Institute of Scientific and Technical Information of China (English)

    马辉; 黄伟; 孙胜玉; 夏鹤春; 孙晓川

    2012-01-01

    目的 利用皮层功能制图进行语言功能区定位,实现语言功能区保护下肿瘤的最大程度切除.方法 对16例语言功能区脑肿瘤患者,利用血氧依赖功能磁共振(BOLD-fMRI)技术和(或)术中唤醒麻醉下皮层直接电刺激( ECS)定位技术进行脑功能制图;对所获皮层功能制图资料进行个体化评估,术中辅助保护语言功能区,在神经导航指引下切除肿瘤.结果 本组肿瘤病变全切除10例,次全切除3例,大部分切除3例.术后语言功能明显改善6例,无变化6例,短暂性感觉性失语2例,语言功能明显障碍2例.结论 BOLD-f MRI结合术中唤醒麻醉下ECS皮层功能制图定位语言功能区,可在保护语言功能的同时最大程度地切除肿瘤组织,提高患者术后生活质量.%Objective To study ihe methods of cortical mapping, preoperative localization of language areas with Bold-fMRI and(or) inlraoperative electrical cortical stimulation of language areas with awaken surgery, assist to remove brain tumors in functional areas of language. Methods Cortical mapping data from such as oxygen dependent functional magnetic resonance imaging (BOLD-fMRI) technology, using the block design and reciting task to activate broca area and paragraph comprehension task to activate wemicke area, calculated cerebral laterality index (LI) to determine the dominant hemisphere; using of the electrical cortical stimulation (ECS) to localizale language areas under awake anesthesia in patients with surgery. The data combined with neuronavigation assist microscopic remove braim tomors in the language areas. Results Functional cortical mapping was used for localizate broca or wemicke area of 16 cases, image acquisition satisfied in 16 cases. Intraoperative awake and electrical stimulation of language areas in 4 cases. Lesion total resection in 10 cases, subtotal resection in 3 cases, partial resection in 3 cases. Language function improved significantly after surgery in 6

  20. mu-Suppression during Action Observation and Execution Correlates with BOLD in Dorsal Premotor, Inferior Parietal, and SI Cortices

    NARCIS (Netherlands)

    Arnstein, Dan; Cui, Fang; Keysers, Christian; Maurits, Natasha M.; Gazzola, Valeria

    2011-01-01

    The discovery of mirror neurons in the monkey, that fire during both the execution and the observation of the same action, sparked great interest in studying the human equivalent. For over a decade, both functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) have been used to

  1. Magnetic stimulation and movement-related cortical activity for acute stroke with hemiparesis.

    Science.gov (United States)

    Matsuura, A; Onoda, K; Oguro, H; Yamaguchi, S

    2015-12-01

    This double-blind, randomized, placebo-controlled study investigated the beneficial effects of repetitive transcranial magnetic stimulation (rTMS) to patients with motor paresis in acute subcortical stroke on functional recovery and electrophysiological measures. Twenty patients with acute stroke were randomized into real rTMS (n = 10) or sham (n = 10) groups. Patients received five daily sessions of rTMS with 1200 pulses at 1 Hz for 20 min or sham stimulation over the contralesional motor cortex. Movement-related cortical potential MRCP, consisting of the Bereitschaftpotential, negative slope (NS') and motor potential (MP), was recorded during self-paced wrist extension of the affected limb associated with assessment of the Fugl-Meyer assessment (FMA) of the upper extremity, the pegboard test and the grip strength before and after the rTMS session. Real rTMS improved the FMA and pegboard test scores compared to the sham group in the affected hand. This improvement was associated with increases in the MP and NS' over the front-central sites in the ipsilesional hemisphere, whereas the sham group did not show significant changes in MRCP components by rTMS. Our findings suggest that low-frequency rTMS to the contralesional motor cortex facilitates functional recovery of paretic limbs in acute stroke patients through enhancing the the neuronal activity of ipsilesional motor and pre-motor areas. © 2015 EAN.

  2. Spatiotemporal imaging of cortical activation during verb generation and picture naming.

    Science.gov (United States)

    Edwards, Erik; Nagarajan, Srikantan S; Dalal, Sarang S; Canolty, Ryan T; Kirsch, Heidi E; Barbaro, Nicholas M; Knight, Robert T

    2010-03-01

    One hundred and fifty years of neurolinguistic research has identified the key structures in the human brain that support language. However, neither the classic neuropsychological approaches introduced by Broca (1861) and Wernicke (1874), nor modern neuroimaging employing PET and fMRI has been able to delineate the temporal flow of language processing in the human brain. We recorded the electrocorticogram (ECoG) from indwelling electrodes over left hemisphere language cortices during two common language tasks, verb generation and picture naming. We observed that the very high frequencies of the ECoG (high-gamma, 70-160 Hz) track language processing with spatial and temporal precision. Serial progression of activations is seen at a larger timescale, showing distinct stages of perception, semantic association/selection, and speech production. Within the areas supporting each of these larger processing stages, parallel (or "incremental") processing is observed. In addition to the traditional posterior vs. anterior localization for speech perception vs. production, we provide novel evidence for the role of premotor cortex in speech perception and of Wernicke's and surrounding cortex in speech production. The data are discussed with regards to current leading models of speech perception and production, and a "dual ventral stream" hybrid of leading speech perception models is given.

  3. Sequential evolution of cortical activity and effective connectivity of swallowing using fMRI.

    Science.gov (United States)

    Mihai, Paul Glad; Otto, Mareile; Platz, Thomas; Eickhoff, Simon B; Lotze, Martin

    2014-12-01

    Swallowing consists of a hierarchical sequence of primary motor and somatosensory processes. The temporal interplay of different phases is complex and clinical disturbances frequent. Of interest was the temporal interaction of the swallowing network. Time resolution optimized functional magnetic resonance imaging was used to describe the temporal sequence of representation sites of swallowing and their functional connectivity. Sixteen young healthy volunteers were investigated who swallowed 2 ml of water 20 times per run with a repetition time for functional imaging of 514 ms. After applying the general linear model approach to identify activation magnitude in preselected regions of interest repeated measures analysis of variance (rmANOVA) was used to detect relevant effects on lateralization, time, and onset. Furthermore, dynamic causal modeling (DCM) was applied to uncover where the input enters the model and the way in which the cortical regions are connected. The temporal analysis revealed a successive activation starting at the premotor cortex, supplementary motor area (SMA), and bilateral thalamus, followed by the primary sensorimotor cortex, the posterior insula, and cerebellum and culminating with activation in the pons shortly before subsiding. The rmANOVA revealed that activation was lateralized initially to the left hemisphere and gradually moved to the right hemisphere over time. The group random effects DCM analysis resulted in a most likely model that consisted of inputs to SMA and M1S1, bidirectionally connected, and a one-way connection from M1S1 to the posterior insula.

  4. Contribution of writing to reading: Dissociation between cognitive and motor process in the left dorsal premotor cortex.

    Science.gov (United States)

    Pattamadilok, Chotiga; Ponz, Aurélie; Planton, Samuel; Bonnard, Mireille

    2016-04-01

    Functional brain imaging studies reported activation of the left dorsal premotor cortex (PMd), that is, a main area in the writing network, in reading tasks. However, it remains unclear whether this area is causally relevant for written stimulus recognition or its activation simply results from a passive coactivation of reading and writing networks. Here, we used chronometric paired-pulse transcranial magnetic stimulation (TMS) to address this issue by disrupting the activity of the PMd, the so-called Exner's area, while participants performed a lexical decision task. Both words and pseudowords were presented in printed and handwritten characters. The latter was assumed to be closely associated with motor representations of handwriting gestures. We found that TMS over the PMd in relatively early time-windows, i.e., between 60 and 160 ms after the stimulus onset, increased reaction times to pseudoword without affecting word recognition. Interestingly, this result pattern was found for both printed and handwritten characters, that is, regardless of whether the characters evoked motor representations of writing actions. Our result showed that under some circumstances the activation of the PMd does not simply result from passive association between reading and writing networks but has a functional role in the reading process. At least, at an early stage of written stimuli recognition, this role seems to depend on a common sublexical and serial process underlying writing and pseudoword reading rather than on an implicit evocation of writing actions during reading as typically assumed.

  5. A dual role of EphB1/ephrin-B3 reverse signaling on migrating striatal and cortical neurons originating in the preoptic area: should I stay or go away ?

    Directory of Open Access Journals (Sweden)

    Judith eRudolph

    2014-07-01

    Full Text Available During embryonic development the preoptic area (POA gives rise to two populations of neurons which are generated at the same time, cortical interneurons and striatal cells. POA-derived cortical interneurons take a superficial path and avoid the developing striatum when they migrate to their target region. We found that EphB1, which is expressed in the striatal anlage, prevents cortical interneurons from entering the striatum via ephrin-B3 reverse signaling. In contrast, for striatal neurons which also express ephrin-B3, EphB1 acts as a stop signal. This dual role of EphB1 is due to differences in ephrin-B3 reverse signaling cascades. For striatal neurons, binding of EphB1 to ephrin-B3 reduces endogenously high levels of pSrc and pFAK, which then causes the cells to stop migration. In contrast, in cortical interneurons EphB1-ephrin-B3 reverse signaling leads to phosphorylation of Src and FAK which then mediates repulsion. Consistent with these in vitro findings, in an ephrin-B3 knockout mouse line, we discovered misrouted cortical interneurons in the striatum and an over-migration of striatal neurons in their target region. Thus, EphB1/ephrin-B3 reverse signaling has a different impact on two sets of neurons which are generated at the same time and place: it can act as a repulsive cue for migrating neurons or it can terminate neuronal migration, a novel role of the Eph/ephrin system.

  6. Probabilistic map of critical functional regions of the human cerebral cortex: Broca's area revisited.

    Science.gov (United States)

    Tate, Matthew C; Herbet, Guillaume; Moritz-Gasser, Sylvie; Tate, Joseph E; Duffau, Hugues

    2014-10-01

    The organization of basic functions of the human brain, particularly in the right hemisphere, remains poorly understood. Recent advances in functional neuroimaging have improved our understanding of cortical organization but do not allow for direct interrogation or determination of essential (versus participatory) cortical regions. Direct cortical stimulation represents a unique opportunity to provide novel insights into the functional distribution of critical epicentres. Direct cortical stimulation (bipolar, 60 Hz, 1-ms pulse) was performed in 165 consecutive patients undergoing awake mapping for resection of low-grade gliomas. Tasks included motor, sensory, counting, and picture naming. Stimulation sites eliciting positive (sensory/motor) or negative (speech arrest, dysarthria, anomia, phonological and semantic paraphasias) findings were recorded and mapped onto a standard Montreal Neurological Institute brain atlas. Montreal Neurological Institute-space functional data were subjected to cluster analysis algorithms (K-means, partition around medioids, hierarchical Ward) to elucidate crucial network epicentres. Sensorimotor function was observed in the pre/post-central gyri as expected. Articulation epicentres were also found within the pre/post-central gyri. However, speech arrest localized to ventral premotor cortex, not the classical Broca's area. Anomia/paraphasia data demonstrated foci not only within classical Wernicke's area but also within the middle and inferior frontal gyri. We report the first bilateral probabilistic map for crucial cortical epicentres of human brain functions in the right and left hemispheres, including sensory, motor, and language (speech, articulation, phonology and semantics). These data challenge classical theories of brain organization (e.g. Broca's area as speech output region) and provide a distributed framework for future studies of neural networks.

  7. Top-down interference and cortical responsiveness in face processing: a TMS-EEG study.

    Science.gov (United States)

    Mattavelli, Giulia; Rosanova, Mario; Casali, Adenauer G; Papagno, Costanza; Romero Lauro, Leonor J

    2013-08-01

    Neuroimaging and electrophysiological studies have shown the involvement of a fronto-temporo-occipital network in face processing, but the functional relation among these areas remains unclear. We used transcranial magnetic stimulation combined with electroencephalography (TMS-EEG) to explore the local and global cortical excitability at rest and during two different face processing behavioral tasks. Single-pulse TMS was delivered (100 ms after face stimulus onset) over the right medial prefrontal cortex (mPFC) during a face identity or a face expression matching task, while continuous EEG was recorded using a 60-channel TMS-compatible amplifier. We examined TMS effects on the occipital face-specific ERP component and compared TMS-evoked potentials (TEPs) recorded during task performance and a passive point fixation control task. TMS reduced the P1-N1 component recorded at the occipital electrodes. Moreover, performing face tasks significantly modulated TEPs recorded at the occipital and temporal electrodes within the first 30 ms after right mPFC stimulation, with a specific increase of temporal TEPs in the right hemisphere for the facial expression task. Furthermore, in order to test the site-specificity of the reported effects, TMS was applied over the right premotor cortex (PMC) as a control site using the same experimental paradigm. Results showed that TMS over the right PMC did not affect ERP components in posterior regions during the face tasks and TEP amplitude did not change between task and no task condition, either at fronto-central electrodes near the stimulation or at temporal and occipital electrodes. These findings support the notion that the prefrontal cortex exerts a very early influence over the occipital cortex during face processing tasks and that excitability across right fronto-temporal cortical regions is significantly modulated during explicit facial expression processing.

  8. It's how you get there: walking down a virtual alley activates premotor and parietal areas

    NARCIS (Netherlands)

    Wagner, J.; Solis-Escalante, T.; Scherer, R.; Neuper, C.; Müller-Putz, G.

    2014-01-01

    Voluntary drive is crucial for motor learning, therefore we are interested in the role that motor planning plays in gait movements. In this study we examined the impact of an interactive Virtual Environment (VE) feedback task on the EEG patterns during robot assisted walking. We compared walking in

  9. Reduced parietal connectivity with a premotor writing area in writer's cramp

    NARCIS (Netherlands)

    Delnooz, C.C.S.; Helmich, R.C.G.; Toni, I.; Warrenburg, B.P.C. van de

    2012-01-01

    Writer's cramp is a task-specific form of dystonia with symptoms characterized by abnormal movements and postures of the hand and arm evident only during writing. Its pathophysiology has been related to faulty sensorimotor integration, abnormal sensory processing, and impaired motor planning. Its sy

  10. Focal cortical dysplasia – review

    Science.gov (United States)

    Kabat, Joanna; Król, Przemysław

    2012-01-01

    Summary Focal cortical dysplasia is a malformation of cortical development, which is the most common cause of medically refractory epilepsy in the pediatric population and the second/third most common etiology of medically intractable seizures in adults. Both genetic and acquired factors are involved in the pathogenesis of cortical dysplasia. Numerous classifications of the complex structural abnormalities of focal cortical dysplasia have been proposed – from Taylor et al. in 1971 to the last modification of Palmini classification made by Blumcke in 2011. In general, three types of cortical dysplasia are recognized. Type I focal cortical dysplasia with mild symptomatic expression and late onset, is more often seen in adults, with changes present in the temporal lobe. Clinical symptoms are more severe in type II of cortical dysplasia usually seen in children. In this type, more extensive changes occur outside the temporal lobe with predilection for the frontal lobes. New type III is one of the above dysplasias with associated another principal lesion as hippocampal sclerosis, tumor, vascular malformation or acquired pathology during early life. Brain MRI imaging shows abnormalities in the majority of type II dysplasias and in only some of type I cortical dysplasias. The most common findings on MRI imaging include: focal cortical thickening or thinning, areas of focal brain atrophy, blurring of the gray-white junction, increased signal on T2- and FLAIR-weighted images in the gray and subcortical white matter often tapering toward the ventricle. On the basis of the MRI findings, it is possible to differentiate between type I and type II cortical dysplasia. A complete resection of the epileptogenic zone is required for seizure-free life. MRI imaging is very helpful to identify those patients who are likely to benefit from surgical treatment in a group of patients with drug-resistant epilepsy. However, in type I cortical dysplasia, MR imaging is often normal, and also

  11. Perfusion SPECT studies with mapping of Brodmann areas in differentiating Alzheimer's disease from frontotemporal degeneration syndromes.

    Science.gov (United States)

    Valotassiou, Varvara; Papatriantafyllou, John; Sifakis, Nikolaos; Tzavara, Chara; Tsougos, Ioannis; Kapsalaki, Eftychia; Hadjigeorgiou, George; Georgoulias, Panagiotis

    2012-12-01

    The aim of this study was to evaluate the contribution of brain perfusion single-photon emission computed tomography (SPECT) studies with mapping of Brodmann areas (BAs) in the differential diagnosis between Alzheimer's disease (AD) and frontotemporal degeneration (FTLD) syndromes. Thirty-nine patients with AD and 73 patients with FTLD syndromes [behavioural variant FTLD (bvFTLD); language variant FTLD (lvFTLD), including semantic dementia (SD) and progressive nonfluent aphasia (PNFA); and corticobasal degeneration (CBD)/progressive supranuclear palsy (PSP) syndromes] underwent brain perfusion SPECT. The NeuroGam software was used for the semiquantitative evaluation of perfusion in BAs of the left (L) and right (R) hemispheres. Compared with those in AD patients, BAs with statistically significant hypoperfusion were found in the prefrontal, orbitofrontal and cingulated cortices and Broca's areas of FTLD and bvFTLD patients; in the temporal and prefrontal cortices and Broca's areas of lvFTLD patients; in the left temporal gyrus of SD patients; in premotor and supplementary motor, prefrontal, orbitofrontal, temporal and anterior cingulated cortices and Broca's areas of PNFA patients; and in the prefrontal, temporal, posterior cingulated and primary and secondary visual cortices of CBD/PSP patients. BA 46R could differentiate AD patients from FTLD and bvFTLD patients; 21L and 25L were found to be independent predictors for lvFTLD in comparison with AD, and 25R, 21L and 23R could differentiate AD patients from PNFA, SD and CBD/PSP patients, respectively. Brain perfusion SPECT with BA mapping in AD and FTLD patients could improve the definition of brain areas that are specifically implicated in these disorders, resulting in a more accurate differential diagnosis.

  12. Wireless Cortical Brain-Machine Interface for Whole-Body Navigation in Primates

    Science.gov (United States)

    Rajangam, Sankaranarayani; Tseng, Po-He; Yin, Allen; Lehew, Gary; Schwarz, David; Lebedev, Mikhail A.; Nicolelis, Miguel A. L.

    2016-03-01

    Several groups have developed brain-machine-interfaces (BMIs) that allow primates to use cortical activity to control artificial limbs. Yet, it remains unknown whether cortical ensembles could represent the kinematics of whole-body navigation and be used to operate a BMI that moves a wheelchair continuously in space. Here we show that rhesus monkeys can learn to navigate a robotic wheelchair, using their cortical activity as the main control signal. Two monkeys were chronically implanted with multichannel microelectrode arrays that allowed wireless recordings from ensembles of premotor and sensorimotor cortical neurons. Initially, while monkeys remained seated in the robotic wheelchair, passive navigation was employed to train a linear decoder to extract 2D wheelchair kinematics from cortical activity. Next, monkeys employed the wireless BMI to translate their cortical activity into the robotic wheelchair’s translational and rotational velocities. Over time, monkeys improved their ability to navigate the wheelchair toward the location of a grape reward. The navigation was enacted by populations of cortical neurons tuned to whole-body displacement. During practice with the apparatus, we also noticed the presence of a cortical representation of the distance to reward location. These results demonstrate that intracranial BMIs could restore whole-body mobility to severely paralyzed patients in the future.

  13. Common premotor regions for the perception and production of prosody and correlations with empathy and prosodic ability.

    Directory of Open Access Journals (Sweden)

    Lisa Aziz-Zadeh

    Full Text Available BACKGROUND: Prosody, the melody and intonation of speech, involves the rhythm, rate, pitch and voice quality to relay linguistic and emotional information from one individual to another. A significant component of human social communication depends upon interpreting and responding to another person's prosodic tone as well as one's own ability to produce prosodic speech. However there has been little work on whether the perception and production of prosody share common neural processes, and if so, how these might correlate with individual differences in social ability. METHODS: The aim of the present study was to determine the degree to which perception and production of prosody rely on shared neural systems. Using fMRI, neural activity during perception and production of a meaningless phrase in different prosodic intonations was measured. Regions of overlap for production and perception of prosody were found in premotor regions, in particular the left inferior frontal gyrus (IFG. Activity in these regions was further found to correlate with how high an individual scored on two different measures of affective empathy as well as a measure on prosodic production ability. CONCLUSIONS: These data indicate, for the first time, that areas that are important for prosody production may also be utilized for prosody perception, as well as other aspects of social communication and social understanding, such as aspects of empathy and prosodic ability.

  14. Cortical connectivity after subcortical stroke assessed with functional magnetic resonance imaging.

    Science.gov (United States)

    Grefkes, Christian; Nowak, Dennis A; Eickhoff, Simon B; Dafotakis, Manuel; Küst, Jutta; Karbe, Hans; Fink, Gereon R

    2008-02-01

    This study aimed at identifying the impact of subcortical stroke on the interaction of cortical motor areas within and across hemispheres during the generation of voluntary hand movements. Twelve subacute stroke patients with a subcortical ischemic lesion and 12 age-matched control subjects were scanned using 3-Tesla functional magnetic resonance imaging. Subjects performed visually paced hand movements with their left, right, or both hands. Changes of effective connectivity among a bilateral network of core motor regions comprising M1, lateral premotor cortex, and the supplementary motor area (SMA) were assessed using dynamic causal modeling. The data showed significant disturbances in the effective connectivity of motor areas in the patients group: Independently from hand movements, the intrinsic neural coupling between ipsilesional SMA and M1, and the interhemispheric coupling of both SMAs was significantly reduced. Furthermore, movements of the stroke-affected hand showed additional inhibitory influences from contralesional to ipsilesional M1 that correlated with the degree of motor impairment. For bimanual movements, interhemispheric communication between ipsilesional SMA and contralesional M1 was significantly reduced, which also correlated with impaired bimanual performance. The motor deficit of patients with a single subcortical lesion is associated with pathological interhemispheric interactions among key motor areas. The data suggest that a dysfunction between ipsilesional and contralesional M1, and between ipsilesional SMA and contralesional M1 underlies hand motor disability after stroke. Assessing effective connectivity by means of functional magnetic resonance imaging and dynamic causal modeling might be used in the future for the evaluation of interventions promoting recovery of function.

  15. Mirror Neurons of Ventral Premotor Cortex Are Modulated by Social Cues Provided by Others' Gaze.

    Science.gov (United States)

    Coudé, Gino; Festante, Fabrizia; Cilia, Adriana; Loiacono, Veronica; Bimbi, Marco; Fogassi, Leonardo; Ferrari, Pier Francesco

    2016-03-16

    Mirror neurons (MNs) in the inferior parietal lobule and ventral premotor cortex (PMv) can code the intentions of other individuals using contextual cues. Gaze direction is an important social cue that can be used for understanding the meaning of actions made by other individuals. Here we addressed the issue of whether PMv MNs are influenced by the gaze direction of another individual. We recorded single-unit activity in macaque PMv while the monkey was observing an experimenter performing a grasping action and orienting his gaze either toward (congruent gaze condition) or away (incongruent gaze condition) from a target object. The results showed that one-half of the recorded MNs were modulated by the gaze direction of the human agent. These gaze-modulated neurons were evenly distributed between those preferring a gaze direction congruent with the direction where the grasping action was performed and the others that preferred an incongruent gaze. Whereas the presence of congruent responses is in line with the usual coupling of hand and gaze in both executed and observed actions, the incongruent responses can be explained by the long exposure of the monkeys to this condition. Our results reveal that the representation of observed actions in PMv is influenced by contextual information not only extracted from physical cues, but also from cues endowed with biological or social value. In this study, we present the first evidence showing that social cues modulate MNs in the monkey ventral premotor cortex. These data suggest that there is an integrated representation of other's hand actions and gaze direction at the single neuron level in the ventral premotor cortex, and support the hypothesis of a functional role of MNs in decoding actions and understanding motor intentions. Copyright © 2016 the authors 0270-6474/16/363145-12$15.00/0.

  16. Viewing the motion of human body parts activates different regions of premotor, temporal, and parietal cortex.

    Science.gov (United States)

    Wheaton, Kylie J; Thompson, James C; Syngeniotis, Ari; Abbott, David F; Puce, Aina

    2004-05-01

    Activation of premotor and temporoparietal cortex occurs when we observe others movements, particularly relating to objects. Viewing the motion of different body parts without the context of an object has not been systematically evaluated. During a 3T fMRI study, 12 healthy subjects viewed human face, hand, and leg motion, which was not directed at or did not involve an object. Activation was identified relative to static images of the same human face, hand, and leg in both individual subject and group average data. Four clear activation foci emerged: (1) right MT/V5 activated to all forms of viewed motion; (2) right STS activated to face and leg motion; (3) ventral premotor cortex activated to face, hand, and leg motion in the right hemisphere and to leg motion in the left hemisphere; and (4) anterior intraparietal cortex (aIP) was active bilaterally to viewing hand motion and in the right hemisphere leg motion. In addition, in the group data, a somatotopic activation pattern for viewing face, hand, and leg motion occurred in right ventral premotor cortex. Activation patterns in STS and aIP were more complex--typically activation foci to viewing two types of human motion showed some overlap. Activation in individual subjects was similar; however, activation to hand motion also occurred in the STS with a variable location across subjects--explaining the lack of a clear activation focus in the group data. The data indicate that there are selective responses to viewing motion of different body parts in the human brain that are independent of object or tool use.

  17. Towards a 'canonical' agranular cortical microcircuit

    Directory of Open Access Journals (Sweden)

    Sarah F. Beul

    2015-01-01

    Full Text Available Based on regularities in the intrinsic microcircuitry of cortical areas, variants of a 'canonical' cortical microcircuit have been proposed and widely adopted, particularly in computational neuroscience and neuroinformatics. However, this circuit is founded on striate cortex, which manifests perhaps the most extreme instance of cortical organization, in terms of a very high density of cells in highly differentiated cortical layers. Most other cortical regions have a less well differentiated architecture, stretching in gradients from the very dense eulaminate primary cortical areas to the other extreme of dysgranular and agranular areas of low density and poor laminar differentiation. It is unlikely for the patterns of inter- and intra-laminar connections to be uniform in spite of strong variations of their structural substrate. This assumption is corroborated by reports of divergence in intrinsic circuitry across the cortex. Consequently, it remains an important goal to define local microcircuits for a variety of cortical types, in particular, agranular cortical regions. As a counterpoint to the striate microcircuit, which may be anchored in an exceptional cytoarchitecture, we here outline a tentative microcircuit for agranular cortex. The circuit is based on a synthesis of the available literature on the local microcircuitry in agranular cortical areas of the rodent brain, investigated by anatomical and electrophysiological approaches. A central observation of these investigations is a weakening of interlaminar inhibition as cortical cytoarchitecture becomes less distinctive. Thus, our study of agranular microcircuitry revealed deviations from the well-known 'canonical' microcircuit established for striate cortex, suggesting variations in the intrinsic circuitry across the cortex that may be functionally relevant.

  18. MEG premotor abnormalities in children with Asperger's syndrome: determinants of social behavior?

    Science.gov (United States)

    Hauswald, Anne; Weisz, Nathan; Bentin, Shlomo; Kissler, Johanna

    2013-07-01

    Children with Asperger's syndrome show deficits in social functioning while their intellectual and language development is intact suggesting a specific dysfunction in mechanisms mediating social cognition. An action observation/execution matching system might be one such mechanism. Recent studies indeed showed that electrophysiological modulation of the "Mu-rhythm" in the 10-12Hz range is weaker when individuals with Asperger's syndrome observe actions performed by others compared to controls. However, electrophysiological studies typically fall short in revealing the neural generators of this activity. To fill this gap we assessed magnetoencephalographic Mu-modulations in Asperger's and typically developed children, while observing grasping movements. Mu-power increased at frontal and central sensors during movement observation. This modulation was stronger in typical than in Asperger children. Source localization revealed stronger sources in premotor cortex, the intraparietal lobule (IPL) and the mid-occipito-temporal gyrus (MOTG) and weaker sources in prefrontal cortex in typical participants compared to Asperger. Activity in premotor regions, IPL and MOTG correlated positively with social competence, whereas prefrontal Mu-sources correlated negatively with social competence. No correlation with intellectual ability was found at any of these sites. These findings localize abnormal Mu-activity in the brain of Asperger children providing evidence which associates motor-system abnormalities with social-function deficits.

  19. Orbitofrontal cortical dysfunction in akinetic catatonia: a functional magnetic resonance imaging study during negative emotional stimulation.

    Science.gov (United States)

    Northoff, Georg; Kötter, Rolf; Baumgart, Frank; Danos, Peter; Boeker, Heinz; Kaulisch, Thomas; Schlagenhauf, Florian; Walter, Henrik; Heinzel, Alexander; Witzel, Thomas; Bogerts, Bernhard

    2004-01-01

    Catatonia is a psychomotor syndrome characterized by concurrent emotional, behavioral, and motor anomalies. Pathophysiological mechanisms of psychomotor disturbances may be related to abnormal emotional-motor processing in prefrontal cortical networks. We therefore investigated prefrontal cortical activation and connectivity patterns during emotional-motor stimulation using functional magnetic resonance imaging (FMRI). We investigated 10 akinetic catatonic patients in a postacute state and compared them with 10 noncatatonic postacute psychiatric controls (age-, sex-, diagnosis-, and medication-matched) and 10 healthy controls. Positive and negative pictures from the International Affective Picture System were used for emotional stimulation. FMRI measurements covered the whole frontal lobe, activation signals in various frontal cortical regions were obtained, and functional connectivity between the different prefrontal cortical regions was investigated using structural equation modeling. Catatonic patients showed alterations in the orbitofrontal cortical activation pattern and in functional connectivity to the premotor cortex in negative and positive emotions compared to psychiatric and healthy controls. Catatonic behavioral and affective symptoms correlated significantly with orbitofrontal activity, whereas catatonic motor symptoms were rather related to medial prefrontal activity. It is concluded that catatonic symptoms may be closely related to dysfunction in the orbitofrontal cortex and consequent alteration in the prefrontal cortical network during emotional processing. Because we investigated postacute patients, orbitofrontal cortical alterations may be interpreted as a trait marker predisposing for development of catatonic syndrome in schizophrenic or affective psychosis.

  20. Sex Differences in Gamma Band Functional Connectivity Between the Frontal Lobe and Cortical Areas During an Auditory Oddball Task, as Revealed by Imaginary Coherence Assessment

    Science.gov (United States)

    Fujimoto, Toshiro; Okumura, Eiichi; Kodabashi, Atsushi; Takeuchi, Kouzou; Otsubo, Toshiaki; Nakamura, Katsumi; Yatsushiro, Kazutaka; Sekine, Masaki; Kamiya, Shinichiro; Shimooki, Susumu; Tamura, Toshiyo

    2016-01-01

    We studied sex-related differences in gamma oscillation during an auditory oddball task, using magnetoencephalography and electroencephalography assessment of imaginary coherence (IC). We obtained a statistical source map of event-related desynchronization (ERD) / event-related synchronization (ERS), and compared females and males regarding ERD / ERS. Based on the results, we chose respectively seed regions for IC determinations in low (30-50 Hz), mid (50-100 Hz) and high gamma (100-150 Hz) bands. In males, ERD was increased in the left posterior cingulate cortex (CGp) at 500 ms in the low gamma band, and in the right caudal anterior cingulate cortex (cACC) at 125 ms in the mid-gamma band. ERS was increased in the left rostral anterior cingulate cortex (rACC) at 375 ms in the high gamma band. We chose the CGp, cACC and rACC as seeds, and examined IC between the seed and certain target regions using the IC map. IC changes depended on the height of the gamma frequency and the time window in the gamma band. Although IC in the mid and high gamma bands did not show sex-specific differences, IC at 30-50 Hz in males was increased between the left rACC and the frontal, orbitofrontal, inferior temporal and fusiform target regions. Increased IC in males suggested that males may acomplish the task constructively, analysingly, emotionally, and by perfoming analysis, and that information processing was more complicated in the cortico-cortical circuit. On the other hand, females showed few differences in IC. Females planned the task with general attention and economical well-balanced processing, which was explained by the higher overall functional cortical connectivity. CGp, cACC and rACC were involved in sex differences in information processing and were likely related to differences in neuroanatomy, hormones and neurotransmitter systems. PMID:27708745

  1. [Agraphia, cortical anarthria and planning disorders as a result of a lesion of the right hemisphere in a right-handed patient].

    Science.gov (United States)

    Demeurisse, G; Coekaerts, M J; Hublet, C

    1984-01-01

    A right-hemisphere premotor cerebral infarct in a right-handed man from a largely left-handed family caused cortical anarthria and constructional agraphia. The effect of programming difficulties on impaired oral and written expression was demonstrated by the clinical picture of pure agraphia, which could thus be attributed to a primary disorder of programming. Measurements of cerebral blood flow three months after the accident showed that language representation was ambilateral.

  2. Stimulation of the pre-SMA influences cerebral blood flow in frontal areas involved with inhibitory control of action.

    Science.gov (United States)

    Obeso, I; Cho, S S; Antonelli, F; Houle, S; Jahanshahi, M; Ko, J H; Strafella, A P

    2013-09-01

    Selection of the most appropriate response necessitates inhibition of competing or prepotent responses. It is important to characterize which cortical areas are relevant to achieve response inhibition. Using the stop signal task, previous imaging studies revealed consistent activation in the right pre-supplementary motor area (pre-SMA). However, imaging alone suffers from the limitation that it can only provide neuronal correlates and cannot establish causality between brain activation and behavior. Repetitive transcranial magnetic stimulation (rTMS) can be used to temporarily interfere with the function of a cortical area considered to play a specific role in the behavior. Thus, we combined rTMS with H(2)(15)O positron emission tomography (PET) scans during the stop signal task, to test whether rTMS-induced changes in excitability of the right pre-SMA influenced response inhibition. We found that rTMS over the pre-SMA increased the efficiency of the inhibitory control over prepotent ongoing responses. A significant interaction was present in the left inferior frontal gyrus (IFG) along with an increase in regional cerebral blood flow (rCBF) in the left pre-SMA, left IFG, right premotor and right inferior parietal cortex. These areas best fitted the path analysis model in the effective connectivity model. The results of this study suggest that stimulation of the right pre-SMA, by interfering with its activity, may have a significant impact on response inhibition. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Abnormal activation of the motor cortical network in idiopathic scoliosis demonstrated by functional MRI.

    Science.gov (United States)

    Domenech, Julio; García-Martí, G; Martí-Bonmatí, L; Barrios, C; Tormos, J M; Pascual-Leone, A

    2011-07-01

    The aetiology of idiopathic scoliosis (IS) remains unknown, but there is growing support for the possibility of an underlying neurological disorder. Functional magnetic resonance imaging (fMRI) can characterize the abnormal activation of the sensorimotor brain network in movement disorders and could provide further insights into the neuropathogenesis of IS. Twenty subjects were included in the study; 10 adolescents with IS (mean age of 15.2, 8 girls and 2 boys) and 10 age-matched healthy controls. The average Cobb angle of the primary curve in the IS patients was 35° (range 27°-55°). All participants underwent a block-design fMRI experiment in a 1.5-Tesla MRI scanner to explore cortical activation following a simple motor task. Rest periods alternated with activation periods during which participants were required to open and close their hand at an internally paced rate of approximately 1 Hz. Data were analyzed with Statistical Parametric Mapping (SPM5) including age, sex and laterality as nuisance variables to minimise the presence of bias in the results. Compared to controls, IS patients showed significant increases in blood oxygenation level dependent (BOLD) activity in contralateral supplementary motor area when performing the motor task with either hand. No significant differences were observed when testing between groups in the functional activation in the primary motor cortex, premotor cortex and somatosensory cortex. Additionally, the IS group showed a greater interhemispheric asymmetry index than the control group (0.30 vs. 0.13, p motor areas during movement execution in patients with IS. These findings support the hypothesis that a sensorimotor integration disorder underlies the pathogenesis of IS.

  4. Premotor spinal network with balanced excitation and inhibition during motor patterns has high resilience to structural division

    DEFF Research Database (Denmark)

    Petersen, Peter C; Vestergaard, Mikkel; Reveles Jensen, Kristian

    2014-01-01

    Direct measurements of synaptic inhibition (I) and excitation (E) to spinal motoneurons can provide an important insight into the organization of premotor networks. Such measurements of flexor motoneurons participating in motor patterns in turtles have recently demonstrated strong concurrent E an...

  5. Dynamic Control of Response Criterion in Premotor Cortex during Perceptual Detection under Temporal Uncertainty.

    Science.gov (United States)

    Carnevale, Federico; de Lafuente, Victor; Romo, Ranulfo; Barak, Omri; Parga, Néstor

    2015-05-20

    Under uncertainty, the brain uses previous knowledge to transform sensory inputs into the percepts on which decisions are based. When the uncertainty lies in the timing of sensory evidence, however, the mechanism underlying the use of previously acquired temporal information remains unknown. We study this issue in monkeys performing a detection task with variable stimulation times. We use the neural correlates of false alarms to infer the subject's response criterion and find that it modulates over the course of a trial. Analysis of premotor cortex activity shows that this modulation is represented by the dynamics of population responses. A trained recurrent network model reproduces the experimental findings and demonstrates a neural mechanism to benefit from temporal expectations in perceptual detection. Previous knowledge about the probability of stimulation over time can be intrinsically encoded in the neural population dynamics, allowing a flexible control of the response criterion over time.

  6. Serum BDNF correlates with connectivity in the (pre)motor hub in the aging human brain--a resting-state fMRI pilot study.

    Science.gov (United States)

    Mueller, Karsten; Arelin, Katrin; Möller, Harald E; Sacher, Julia; Kratzsch, Jürgen; Luck, Tobias; Riedel-Heller, Steffi; Villringer, Arno; Schroeter, Matthias L

    2016-02-01

    Brain-derived neurotrophic factor (BDNF) has been discussed to be involved in plasticity processes in the human brain, in particular during aging. Recently, aging and its (neurodegenerative) diseases have increasingly been conceptualized as disconnection syndromes. Here, connectivity changes in neural networks (the connectome) are suggested to be the most relevant and characteristic features for such processes or diseases. To further elucidate the impact of aging on neural networks, we investigated the interaction between plasticity processes, brain connectivity, and healthy aging by measuring levels of serum BDNF and resting-state fMRI data in 25 young (mean age 24.8 ± 2.7 (SD) years) and 23 old healthy participants (mean age, 68.6 ± 4.1 years). To identify neural hubs most essentially related to serum BDNF, we applied graph theory approaches, namely the new data-driven and parameter-free approach eigenvector centrality (EC) mapping. The analysis revealed a positive correlation between serum BDNF and EC in the premotor and motor cortex in older participants in contrast to young volunteers, where we did not detect any association. This positive relationship between serum BDNF and EC appears to be specific for older adults. Our results might indicate that the amount of physical activity and learning capacities, leading to higher BDNF levels, increases brain connectivity in (pre)motor areas in healthy aging in agreement with rodent animal studies. Pilot results have to be replicated in a larger sample including behavioral data to disentangle the cause for the relationship between BDNF levels and connectivity. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. fMRI in preoperative assessment of sensorimotor areas: correlation with direct cortical stimulation%功能磁共振与皮层电刺激定位感觉运动区的比较

    Institute of Scientific and Technical Information of China (English)

    徐虎; 徐纪文; 赵晨杰; 王桂松; 周洪语; 田鑫

    2010-01-01

    Objective To study the accuracy of functional magnetic resonance imaging (fMRI) by comparing the relationship between the preoperative fMRI with blood oxygen level dependent (BOLD) technique and cortical stimulation for cortical mapping of sensorimotor areas in patients with epilepsy.And to estimate the significance of fMRI in localizing the functional areas as well as its clinical application value.Methods A flexion and extension of fingers tasks were used for 14 refractory epilepsy patients,whose EEG demonstrated that the abnormal discharge part was located in sensorimotor areas.A standard 3.0T MR images system was utilized to localize the sensorimotor areas,using the BOLD contrast technique.The BOLD images were integrated with the routine navigational MR images (T1-weighted three-dimensional fast spoiled gradient recalled sequence).All the patients accepted operation twice.In the first operation we implanted cortical electrodes to the abnormal discharge areas.Postoperative continuous CT scan was performed to make sure the relationship between electrodes and skull.The second operation was lesion resection.The CT images were integrated with merged images above by navigation form 3D images,which consisted of activated functional area and electrodes.After the first operation the cortical electrostimulation was also performed,the overlapping was used to adjust the relationship between areas activated by flexion and extension of fingers tasks in BOLD-fMRI and site inducing sensorimotor interruption in postoperative cortical electrostimulatior.Results The activation sites of 14 patients were mainly localized in contralateral precentral gyrus,contralateral postcentral gyrus,supplementary motor area and cerebellum.The cortical electrostimulation results of 11 patients demonstrated that the concordance between fMRI and electrostimulation was found to be 91.7%.Conclusion BOLD-fMRI is a highly sensitive and accuracy technique to locate sensorimotor areas and has a

  8. Motor-language coupling: direct evidence from early Parkinson's disease and intracranial cortical recordings.

    Science.gov (United States)

    Ibáñez, Agustín; Cardona, Juan F; Dos Santos, Yamil Vidal; Blenkmann, Alejandro; Aravena, Pía; Roca, María; Hurtado, Esteban; Nerguizian, Mirna; Amoruso, Lucía; Gómez-Arévalo, Gonzalo; Chade, Anabel; Dubrovsky, Alberto; Gershanik, Oscar; Kochen, Silvia; Glenberg, Arthur; Manes, Facundo; Bekinschtein, Tristán

    2013-04-01

    Language and action systems are functionally coupled in the brain as demonstrated by converging evidence using Functional magnetic resonance imaging (fMRI), electroencephalography (EEG), transcranial magnetic stimulation (TMS), and lesion studies. In particular, this coupling has been demonstrated using the action-sentence compatibility effect (ACE) in which motor activity and language interact. The ACE task requires participants to listen to sentences that described actions typically performed with an open hand (e.g., clapping), a closed hand (e.g., hammering), or without any hand action (neutral); and to press a large button with either an open hand position or closed hand position immediately upon comprehending each sentence. The ACE is defined as a longer reaction time (RT) in the action-sentence incompatible conditions than in the compatible conditions. Here we investigated direct motor-language coupling in two novel and uniquely informative ways. First, we measured the behavioural ACE in patients with motor impairment (early Parkinson's disease - EPD), and second, in epileptic patients with direct electrocorticography (ECoG) recordings. In experiment 1, EPD participants with preserved general cognitive repertoire, showed a much diminished ACE relative to non-EPD volunteers. Moreover, a correlation between ACE performance and action-verb processing (kissing and dancing test - KDT) was observed. Direct cortical recordings (ECoG) in motor and language areas (experiment 2) demonstrated simultaneous bidirectional effects: motor preparation affected language processing (N400 at left inferior frontal gyrus and middle/superior temporal gyrus), and language processing affected activity in movement-related areas (motor potential at premotor and M1). Our findings show that the ACE paradigm requires ongoing integration of preserved motor and language coupling (abolished in EPD) and engages motor-temporal cortices in a bidirectional way. In addition, both experiments

  9. Zif268 mRNA Expression Patterns Reveal a Distinct Impact of Early Pattern Vision Deprivation on the Development of Primary Visual Cortical Areas in the Cat.

    Science.gov (United States)

    Laskowska-Macios, Karolina; Zapasnik, Monika; Hu, Tjing-Tjing; Kossut, Malgorzata; Arckens, Lutgarde; Burnat, Kalina

    2015-10-01

    Pattern vision deprivation (BD) can induce permanent deficits in global motion perception. The impact of timing and duration of BD on the maturation of the central and peripheral visual field representations in cat primary visual areas 17 and 18 remains unknown. We compared early BD, from eye opening for 2, 4, or 6 months, with late onset BD, after 2 months of normal vision, using the expression pattern of the visually driven activity reporter gene zif268 as readout. Decreasing zif268 mRNA levels between months 2 and 4 characterized the normal maturation of the (supra)granular layers of the central and peripheral visual field representations in areas 17 and 18. In general, all BD conditions had higher than normal zif268 levels. In area 17, early BD induced a delayed decrease, beginning later in peripheral than in central area 17. In contrast, the decrease occurred between months 2 and 4 throughout area 18. Lack of pattern vision stimulation during the first 4 months of life therefore has a different impact on the development of areas 17 and 18. A high zif268 expression level at a time when normal vision is restored seems to predict the capacity of a visual area to compensate for BD.

  10. Holistic face categorization in higher-level cortical visual areas of the normal and prosopagnosic brain: towards a non-hierarchical view of face perception

    Directory of Open Access Journals (Sweden)

    Bruno Rossion

    2011-01-01

    Full Text Available How a visual stimulus is initially categorized as a face in a network of human brain areas remains largely unclear. Hierarchical neuro-computational models of face perception assume that the visual stimulus is first decomposed in local parts in lower order visual areas. These parts would then be combined into a global representation in higher order face-sensitive areas of the occipito-temporal cortex. Here we tested this view in fMRI with visual stimuli that are categorized as faces based on their global configuration rather than their local parts (2-tones Mooney figures and Arcimboldo’s facelike paintings. Compared to the same inverted visual stimuli that are not categorized as faces, these stimuli activated the right middle fusiform gyrus (Fusiform face area, FFA and superior temporal sulcus (pSTS, with no significant activation in the posteriorly located inferior occipital gyrus (i.e., no occipital face area, OFA. This observation is strengthened by behavioral and neural evidence for normal face categorization of these stimuli in a brain-damaged prosopagnosic patient (PS whose intact right middle fusiform gyrus and superior temporal sulcus are devoid of any potential face-sensitive inputs from the lesioned right inferior occipital cortex. Together, these observations indicate that face-preferential activation may emerge in higher order visual areas of the right hemisphere without any face-preferential inputs from lower order visual areas, supporting a non-hierarchical view of face perception in the visual cortex.

  11. From perceptual to lexico-semantic analysis--cortical plasticity enabling new levels of processing.

    Science.gov (United States)

    Schlaffke, Lara; Rüther, Naima N; Heba, Stefanie; Haag, Lauren M; Schultz, Thomas; Rosengarth, Katharina; Tegenthoff, Martin; Bellebaum, Christian; Schmidt-Wilcke, Tobias

    2015-11-01

    Certain kinds of stimuli can be processed on multiple levels. While the neural correlates of different levels of processing (LOPs) have been investigated to some extent, most of the studies involve skills and/or knowledge already present when performing the task. In this study we specifically sought to identify neural correlates of an evolving skill that allows the transition from perceptual to a lexico-semantic stimulus analysis. Eighteen participants were trained to decode 12 letters of Morse code that were presented acoustically inside and outside of the scanner environment. Morse code was presented in trains of three letters while brain activity was assessed with fMRI. Participants either attended to the stimulus length (perceptual analysis), or evaluated its meaning distinguishing words from nonwords (lexico-semantic analysis). Perceptual and lexico-semantic analyses shared a mutual network comprising the left premotor cortex, the supplementary motor area (SMA) and the inferior parietal lobule (IPL). Perceptual analysis was associated with a strong brain activation in the SMA and the superior temporal gyrus bilaterally (STG), which remained unaltered from pre and post training. In the lexico-semantic analysis post learning, study participants showed additional activation in the left inferior frontal cortex (IFC) and in the left occipitotemporal cortex (OTC), regions known to be critically involved in lexical processing. Our data provide evidence for cortical plasticity evolving with a learning process enabling the transition from perceptual to lexico-semantic stimulus analysis. Importantly, the activation pattern remains task-related LOP and is thus the result of a decision process as to which LOP to engage in.

  12. The action of pulse-modulated GSM radiation increases regional changes in brain activity and c-Fos expression in cortical and subcortical areas in a rat model of picrotoxin-induced seizure proneness.

    Science.gov (United States)

    López-Martín, E; Bregains, J; Relova-Quinteiro, J L; Cadarso-Suárez, C; Jorge-Barreiro, F J; Ares-Pena, F J

    2009-05-01

    The action of the pulse-modulated GSM radiofrequency of mobile phones has been suggested as a physical phenomenon that might have biological effects on the mammalian central nervous system. In the present study, GSM-exposed picrotoxin-pretreated rats showed differences in clinical and EEG signs, and in c-Fos expression in the brain, with respect to picrotoxin-treated rats exposed to an equivalent dose of unmodulated radiation. Neither radiation treatment caused tissue heating, so thermal effects can be ruled out. The most marked effects of GSM radiation on c-Fos expression in picrotoxin-treated rats were observed in limbic structures, olfactory cortex areas and subcortical areas, the dentate gyrus, and the central lateral nucleus of the thalamic intralaminar nucleus group. Nonpicrotoxin-treated animals exposed to unmodulated radiation showed the highest levels of neuronal c-Fos expression in cortical areas. These results suggest a specific effect of the pulse modulation of GSM radiation on brain activity of a picrotoxin-induced seizure-proneness rat model and indicate that this mobile-phone-type radiation might induce regional changes in previous preexcitability conditions of neuronal activation.

  13. A Multi-Area Stochastic Model for a Covert Visual Search Task.

    Directory of Open Access Journals (Sweden)

    Michael A Schwemmer

    Full Text Available Decisions typically comprise several elements. For example, attention must be directed towards specific objects, their identities recognized, and a choice made among alternatives. Pairs of competing accumulators and drift-diffusion processes provide good models of evidence integration in two-alternative perceptual choices, but more complex tasks requiring the coordination of attention and decision making involve multistage processing and multiple brain areas. Here we consider a task in which a target is located among distractors and its identity reported by lever release. The data comprise reaction times, accuracies, and single unit recordings from two monkeys' lateral interparietal area (LIP neurons. LIP firing rates distinguish between targets and distractors, exhibit stimulus set size effects, and show response-hemifield congruence effects. These data motivate our model, which uses coupled sets of leaky competing accumulators to represent processes hypothesized to occur in feature-selective areas and limb motor and pre-motor areas, together with the visual selection process occurring in LIP. Model simulations capture the electrophysiological and behavioral data, and fitted parameters suggest that different connection weights between LIP and the other cortical areas may account for the observed behavioral differences between the animals.

  14. Sustained attention to spontaneous thumb sensations activates brain somatosensory and other proprioceptive areas.

    Science.gov (United States)

    Bauer, Clemens C C; Díaz, José-Luis; Concha, Luis; Barrios, Fernando A

    2014-06-01

    The present experiment was designed to test if sustained attention directed to the spontaneous sensations of the right or left thumb in the absence of any external stimuli is able to activate corresponding somatosensory brain areas. After verifying in 34 healthy volunteers that external touch stimuli to either thumb effectively activate brain contralateral somatosensory areas, and after subtracting attention mechanisms employed in both touch and spontaneous-sensation conditions, fMRI evidence was obtained that the primary somatosensory cortex (specifically left BA 3a/3b) becomes active when an individual is required to attend to the spontaneous sensations of either thumb in the absence of external stimuli. In addition, the left superior parietal cortex, anterior cingulate gyrus, insula, motor and premotor cortex, left dorsolateral prefrontal cortex, Broca's area, and occipital cortices were activated. Moreover, attention to spontaneous-sensations revealed an increased connectivity between BA 3a/3b, superior frontal gyrus (BA 9) and anterior cingulate cortex (BA 32), probably allowing top-down activations of primary somatosensory cortex. We conclude that specific primary somatosensory areas in conjunction with other left parieto-frontal areas are involved in processing proprioceptive and interoceptive bodily information that underlies own body-representations and that these networks and cognitive functions can be modulated by top-down attentional processes.

  15. Mapping the cortical representation of speech sounds in a syllable repetition task.

    Science.gov (United States)

    Markiewicz, Christopher J; Bohland, Jason W

    2016-11-01

    Speech repetition relies on a series of distributed cortical representations and functional pathways. A speaker must map auditory representations of incoming sounds onto learned speech items, maintain an accurate representation of those items in short-term memory, interface that representation with the motor output system, and fluently articulate the target sequence. A "dorsal stream" consisting of posterior temporal, inferior parietal and premotor regions is thought to mediate auditory-motor representations and transformations, but the nature and activation of these representations for different portions of speech repetition tasks remains unclear. Here we mapped the correlates of phonetic and/or phonological information related to the specific phonemes and syllables that were heard, remembered, and produced using a series of cortical searchlight multi-voxel pattern analyses trained on estimates of BOLD responses from individual trials. Based on responses linked to input events (auditory syllable presentation), predictive vowel-level information was found in the left inferior frontal sulcus, while syllable prediction revealed significant clusters in the left ventral premotor cortex and central sulcus and the left mid superior temporal sulcus. Responses linked to output events (the GO signal cueing overt production) revealed strong clusters of vowel-related information bilaterally in the mid to posterior superior temporal sulcus. For the prediction of onset and coda consonants, input-linked responses yielded distributed clusters in the superior temporal cortices, which were further informative for classifiers trained on output-linked responses. Output-linked responses in the Rolandic cortex made strong predictions for the syllables and consonants produced, but their predictive power was reduced for vowels. The results of this study provide a systematic survey of how cortical response patterns covary with the identity of speech sounds, which will help to constrain

  16. Increased activity of pre-motor network does not change the excitability of motoneurons during protracted scratch initiation

    DEFF Research Database (Denmark)

    Guzulaitis, Robertas; Alaburda, Aidas; Hounsgaard, Jørn Dybkjær

    2013-01-01

    Intrinsic response properties of neurons change during network activity. These changes may reinforce the initiation of particular forms of network activity. If so, the involvement of neurons in particular behaviors in multifunctional networks could be determined by up or down regulation...... of their intrinsic excitability. Here we employed an experimental paradigm of protracted scratch initiation in the integrated carapace-spinal cord preparation of adult turtles (Chrysemys scripta elegans). The protracted initiation of scratch network activity allows us to investigate the excitability of motoneurons...... and pre-motor network activity in the time interval from the start of sensory stimulation until the onset of scratch activity. Our results suggest that increased activity in the pre-motor network facilitates the onset of scratch episodes but does not change the excitability of motoneurons at the onset...

  17. Inhibitory and facilitatory connectivity from ventral premotor to primary motor cortex in healthy humans at rest--a bifocal TMS study

    DEFF Research Database (Denmark)

    Bäumer, T; Schippling, S; Kroeger, J;

    2009-01-01

    OBJECTIVE: In macaques, intracortical electrical stimulation of ventral premotor cortex (PMv) can modulate ipsilateral primary motor cortex (M1) excitability at short interstimulus intervals (ISIs). METHODS: Adopting the same conditioning-test approach, we used bifocal transcranial magnetic...

  18. Cortical Lewy Body Dementia

    Directory of Open Access Journals (Sweden)

    W. R. G. Gibb

    1990-01-01

    Full Text Available In cortical Lewy body dementia the distribution of Lewy bodies in the nervous system follows that of Parkinson's disease, except for their greater profusion in the cerebral cortex. The cortical tangles and plaques of Alzheimer pathology are often present, the likely explanation being that Alzheimer pathology provokes dementia in many patients. Pure cortical Lewy body dementia without Alzheimer pathology is uncommon. The age of onset reflects that of Parkinson's disease, and clinical features, though not diagnostic, include aphasias, apraxias, agnosias, paranoid delusions and visual hallucinations. Parkinsonism may present before or after the dementia, and survival duration is approximately half that seen in Parkinson's disease without dementia.

  19. Role of human premotor dorsal region in learning a conditional visuomotor task.

    Science.gov (United States)

    Parikh, Pranav J; Santello, Marco

    2017-01-01

    Conditional learning is an important component of our everyday activities (e.g., handling a phone or sorting work files) and requires identification of the arbitrary stimulus, accurate selection of the motor response, monitoring of the response, and storing in memory of the stimulus-response association for future recall. Learning this type of conditional visuomotor task appears to engage the premotor dorsal region (PMd). However, the extent to which PMd might be involved in specific or all processes of conditional learning is not well understood. Using transcranial magnetic stimulation (TMS), we demonstrate the role of human PMd in specific stages of learning of a novel conditional visuomotor task that required subjects to identify object center of mass using a color cue and to apply appropriate torque on the object at lift onset to minimize tilt. TMS over PMd, but not vertex, increased error in torque exerted on the object during the learning trials. Analyses of digit position and forces further revealed that the slowing in conditional visuomotor learning resulted from impaired monitoring of the object orientation during lift, rather than stimulus identification, thus compromising the ability to accurately reduce performance error across trials. Importantly, TMS over PMd did not alter production of torque based on the recall of learned color-torque associations. We conclude that the role of PMd for conditional learning is highly sensitive to the stage of learning visuomotor associations.

  20. Psychosocial risk factors, pre-motor symptoms and first-time hospitalization with Parkinson's disease

    DEFF Research Database (Denmark)

    Clark, Alice Jessie; Ritz, B; Prescott, E;

    2013-01-01

    BACKGROUND AND PURPOSE: Experimental studies support a link between stress and development of parkinsonian symptoms, but prospective population studies are lacking. The aim of the current study is to determine the effects of several psychosocial factors on the risk of Parkinson's disease (PD), as...... PD. Vital exhaustion may be useful for screening aimed at early detection and when considering disease-modifying therapies in people at high risk of clinical PD.......BACKGROUND AND PURPOSE: Experimental studies support a link between stress and development of parkinsonian symptoms, but prospective population studies are lacking. The aim of the current study is to determine the effects of several psychosocial factors on the risk of Parkinson's disease (PD......), as well as to identify potential pre-motor symptoms for PD in a large prospective cohort study. METHODS: In 1991-1993, a total of 9955 women and men free of PD from the Copenhagen City Heart Study were asked about major life events, economic hardship, social network, impaired sleep and vital exhaustion...

  1. Risk of premotor symptoms in patients with newly diagnosed PD: a nationwide, population-based, case-control study in Taiwan.

    Directory of Open Access Journals (Sweden)

    Yu-Hsuan Wu

    Full Text Available To evaluate the risk of premotor symptoms, namely rapid eye movement behavior disorder (RBD, constipation, and depression among patients with newly diagnosed Parkinson disease (PD.A total of 705 PD patients and 2,820 control subjects were selected from the Taiwan National Health Insurance Research Database. Patients were traced back for a maximum of 14 years to determine the diagnoses of RBD, depression, and constipation. Logistic regression analysis was used to identify risk of premotor symptoms for PD. Moreover, subgroup analyses were performed by dividing the patients into a middle-age onset group (≤ 64 years and an old-age onset group (≥ 65 years. The associations between these premotor symptoms and age of PD onset were further examined.An association was found between a history of premotor symptoms and newly diagnosed PD in which a high occurrence of premotor symptoms was identified in PD patients as compared to selected controls (4.3% vs. 1.2% for RBD, 40.4% vs. 24.0% for constipation, and 13.0% vs. 5.1% for depression. The strength of this association remained statistically significant after adjustment for potential confounders (3.69 fold risk for RBD, 2.36 for constipation, and 2.82 for depression, all p < 0.0001. The average interval between premotor symptoms and PD ranged from 4.5 to 6.2 years. RBD and depression carried higher risks for PD in the middle-age onset group than in the old-age onset group (7.20- vs. 2.24-fold risk for RBD, 6.06 vs. 1.40 for depression.The prevalence of premotor symptoms was higher among the PD patients than in the controls. Premotor symptoms appeared to be associated with a higher risk for PD in subjects with an earlier age of onset.

  2. Increased resting state connectivity between ipsilesional motor cortex and contralesional premotor cortex after transcranial direct current stimulation with physical therapy.

    Science.gov (United States)

    Chen, Joyce L; Schlaug, Gottfried

    2016-03-16

    Non-invasive stimulation of the brain using transcranial direct current stimulation (tDCS) during motor rehabilitation can improve the recovery of movements in individuals with stroke. However, the neural substrates that underlie the clinical improvements are not well understood. In this proof-of-principle open-label pilot study, five individuals with stroke received 10 sessions of tDCS while undergoing usual care physical/occupational therapy for the arm and hand. Motor impairment as indexed by the Upper Extremity Fugl Meyer assessment was significantly reduced after the intervention. Resting state fMRI connectivity increased between ipsilesional motor cortex and contralesional premotor cortex after the intervention. These findings provide preliminary evidence that the neural underpinnings of tDCS coupled with rehabilitation exercises, may be mediated by interactions between motor and premotor cortex. The latter, of which has been shown to play an important role in the recovery of movements post-stroke. Our data suggest premotor cortex could be tested as a target region for non-invasive brain-stimulation to enhance connectivity between regions that might be beneficial for stroke motor recovery.

  3. Interaction between the premotor processes of eye and hand movements: possible mechanism underlying eye-hand coordination.

    Science.gov (United States)

    Hiraoka, Koichi; Kurata, Naoatsu; Sakaguchi, Masato; Nonaka, Kengo; Matsumoto, Naoto

    2014-03-01

    Interaction between the execution process of eye movement and that of hand movement must be indispensable for eye-hand coordination. The present study investigated corticospinal excitability in the hand muscles during the premotor processes of eye and/or hand movement to elucidate interaction between these processes. Healthy humans performed a precued reaction task of eye and/or finger movement and motor-evoked potentials in the hand muscles were evoked in the reaction time. Leftward eye movement suppressed corticospinal excitability in the right abductor digiti minimi muscle only when little finger abduction was simultaneously executed. Corticospinal excitability in the first dorsal interosseous muscle was not suppressed by eye movement regardless of whether or not it was accompanied by finger movement. Suppression of corticospinal excitability in the hand muscles induced by eye movement in the premotor period depends on the direction of eye movement, the muscle tested, and the premotor process of the tested muscle. The suppression may reflect interaction between the motor process of eye movement and that of hand movement particularly active during eye-hand coordination tasks during which both processes proceed.

  4. 帕金森病运动前期研究进展%Premotor Phase of Early Parkinson Disease (review)

    Institute of Scientific and Technical Information of China (English)

    焦淑军; 袁红

    2011-01-01

    Clinical, neuroimaging, and pathologic studies suggested that a variety of nonmotor symptoms, such as olfactory dysfunction, dysautonomia, and mood and sleep disorders, can precede the typic motor features of Parkinson disease (PD) by years and, perhaps, even decades.The period when these symptoms arise can be referred as the premotor phase of the disease.This paper reviewed the conception, clinical manifestation, pathology, diogose of the premotor phase of early Parkinson disease.%临床症状学及神经影像学、病理学的资料均提示各种帕金森病(PD)非运动症状(NMS),如嗅觉障碍、自主神经机能异常、情感障碍、睡眠紊乱等,先于运动症状出现数年至十数年,这段时期称为运动前期(premotor phase).本文对帕金森病运动前期概念、临床表现、病理基础、诊断的研究进展做一综述.

  5. Increased resting state connectivity between ipsilesional motor cortex and contralesional premotor cortex after transcranial direct current stimulation with physical therapy

    Science.gov (United States)

    Chen, Joyce L; Schlaug, Gottfried

    2016-01-01

    Non-invasive stimulation of the brain using transcranial direct current stimulation (tDCS) during motor rehabilitation can improve the recovery of movements in individuals with stroke. However, the neural substrates that underlie the clinical improvements are not well understood. In this proof-of-principle open-label pilot study, five individuals with stroke received 10 sessions of tDCS while undergoing usual care physical/occupational therapy for the arm and hand. Motor impairment as indexed by the Upper Extremity Fugl Meyer assessment was significantly reduced after the intervention. Resting state fMRI connectivity increased between ipsilesional motor cortex and contralesional premotor cortex after the intervention. These findings provide preliminary evidence that the neural underpinnings of tDCS coupled with rehabilitation exercises, may be mediated by interactions between motor and premotor cortex. The latter, of which has been shown to play an important role in the recovery of movements post-stroke. Our data suggest premotor cortex could be tested as a target region for non-invasive brain-stimulation to enhance connectivity between regions that might be beneficial for stroke motor recovery. PMID:26980052

  6. Postpartum cortical blindness.

    Science.gov (United States)

    Faiz, Shakeel Ahmed

    2008-09-01

    A 30-years-old third gravida with previous normal pregnancies and an unremarkable prenatal course had an emergency lower segment caesarean section at a periphery hospital for failure of labour to progress. She developed bilateral cortical blindness immediately after recovery from anesthesia due to cerebral angiopathy shown by CT and MR scan as cortical infarct cerebral angiopathy, which is a rare complication of a normal pregnancy.

  7. Body-Selective Areas in the Visual Cortex are less active in Children than in Adults

    Directory of Open Access Journals (Sweden)

    Paddy D Ross

    2014-11-01

    Full Text Available Our ability to read other people’s non-verbal signals gets refined throughout childhood and adolescence. How this is paralleled by brain development has been investigated mainly with regards to face perception, showing a protracted functional development of the face-selective visual cortical areas. In view of the importance of whole-body expressions in interpersonal communication it is important to understand the development of brain areas sensitive to these social signals.Here we used functional magnetic resonance imaging (fMRI to compare brain activity in a group of 24 children (age 6-11 and 26 adults while they passively watched short videos of body or object movements. We observed activity in similar regions in both groups; namely the extra-striate body area (EBA, fusiform body area (FBA, posterior superior temporal sulcus (pSTS, amygdala and premotor regions. Adults showed additional activity in the inferior frontal gyrus. Within the main body-selective regions (EBA, FBA and pSTS, the strength and spatial extent of fMRI signal change was larger in adults than in children. Multivariate Bayesian analysis showed that the spatial pattern of neural representation within those regions did not change over age.Our results indicate, for the first time, that body perception, like face perception, is still maturing through the second decade of life.

  8. Mirror neurons in monkey area F5 do not adapt to the observation of repeated actions.

    Science.gov (United States)

    Caggiano, Vittorio; Pomper, Joern K; Fleischer, Falk; Fogassi, Leonardo; Giese, Martin; Thier, Peter

    2013-01-01

    Repetitive presentation of the same visual stimulus entails a response decrease in the action potential discharge of neurons in various areas of the monkey visual cortex. It is still unclear whether this repetition suppression effect is also present in single neurons in cortical premotor areas responding to visual stimuli, as suggested by the human functional magnetic resonance imaging literature. Here we report the responses of 'mirror neurons' in monkey area F5 to the repeated presentation of action movies. We find that most single neurons and the population at large do not show a significant decrease of the firing rate. On the other hand, simultaneously recorded local field potentials exhibit repetition suppression. As local field potentials are believed to be better linked to the blood-oxygen-level-dependent (BOLD) signal exploited by functional magnetic resonance imaging, these findings suggest caution when trying to derive conclusions on the spiking activity of neurons in a given area based on the observation of BOLD repetition suppression.

  9. Cortical hierarchy governs rat claustrocortical circuit organization.

    Science.gov (United States)

    White, Michael G; Cody, Patrick A; Bubser, Michael; Wang, Hui-Dong; Deutch, Ariel Y; Mathur, Brian N

    2017-04-15

    The claustrum is a telencephalic gray matter structure with various proposed functions, including sensory integration and attentional allocation. Underlying these concepts is the reciprocal connectivity of the claustrum with most, if not all, areas of the cortex. What remains to be elucidated to inform functional hypotheses further is whether a pattern exists in the strength of connectivity between a given cortical area and the claustrum. To this end, we performed a series of retrograde neuronal tract tracer injections into rat cortical areas along the cortical processing hierarchy, from primary sensory and motor to frontal cortices. We observed that the number of claustrocortical projections increased as a function of processing hierarchy; claustrum neurons projecting to primary sensory cortices were scant and restricted in distribution across the claustrum, whereas neurons projecting to the cingulate cortex were densely packed and more evenly distributed throughout the claustrum. This connectivity pattern suggests that the claustrum may preferentially subserve executive functions orchestrated by the cingulate cortex. J. Comp. Neurol. 525:1347-1362, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  10. Anatomical and functional pathways of rhythmogenic inspiratory premotor information flow originating in the pre-Bötzinger complex in the rat medulla.

    Science.gov (United States)

    Koshiya, N; Oku, Y; Yokota, S; Oyamada, Y; Yasui, Y; Okada, Y

    2014-05-30

    The pre-Bötzinger complex (preBötC) of the ventrolateral medulla is the kernel for inspiratory rhythm generation. However, it is not fully understood how inspiratory neural activity is generated in the preBötC and propagates to other medullary regions. We analyzed the detailed anatomical connectivity to and from the preBötC and functional aspects of the inspiratory information propagation from the preBötC on the transverse plane of the medulla oblongata. Tract-tracing with immunohistochemistry in young adult rats demonstrated that neurokinin-1 receptor- and somatostatin-immunoreactive neurons in the preBötC, which could be involved in respiratory rhythmogenesis, are embedded in the plexus of axons originating in the contralateral preBötC. By voltage-imaging in rhythmically active slices of neonatal rats, we analyzed origination and propagation of inspiratory neural activity as depolarizing wave dynamics on the entire transverse plane as well as within the preBötC. Novel combination of pharmacological blockade of glutamatergic transmission and mathematical subtraction of the video images under blockade from the control images enabled to extract glutamatergic signal propagations. By ultra-high-speed voltage-imaging we first demonstrated the inter-preBötC conduction process of inspiratory action potentials. Intra-preBötC imaging with high spatiotemporal resolution during a single spontaneous inspiratory cycle unveiled deterministic nonlinearities, i.e., chaos, in the population recruitment. Collectively, we comprehensively elucidated the anatomical pathways to and from the preBötC and dynamics of inspiratory neural information propagation: (1) From the preBötC in one side to the contralateral preBötC, which would synchronize the bilateral rhythmogenic kernels, (2) from the preBötC directly to the bilateral hypoglossal premotor and motor areas as well as to the nuclei tractus solitarius, and (3) from the hypoglossal premotor areas toward the hypoglossal

  11. Interest of targeting either cortical area Brodmann 9 or 46 in rTMS treatment for depression: a preliminary randomized study.

    Science.gov (United States)

    Trojak, Benoit; Meille, Vincent; Jonval, Lysiane; Schuffenecker, Nicolas; Haffen, Emmanuel; Schwan, Raymund; Bonin, Bernard; Chauvet-Gelinier, Jean-Christophe

    2014-12-01

    To assess the interest of specifically targeting Brodmann Areas (BA) 9 or 46 for rTMS treatment of depression. Patients with Treatment-Resistant Depression were randomly assigned to two treatment groups to receive either rTMS on BA 9 or on BA 46. Each patient underwent 10 sessions of 1Hz-rTMS for 2weeks. The Hamilton and Montgomery-Asberg Depression Rating Scales (HDRS, MADRS) were used under blind conditions to assess the therapeutic response (50% improvement). A Wilcoxon signed-rank test was used to compare the depression rating scales scores obtained before and after the 10 rTMS sessions for each of the two groups. The therapeutic results in the two groups were compared using the Mann-Whitney-Wilcoxon test. We also reported the effect sizes using Hedges's g. Fifteen patients were included. Stimulation of both BA 9 (n=7) and BA 46 (n=8) led to similar therapeutic responses in the two groups (with moderate effect size), such as the mean decrease in HDRS (BA 9: p=0.015; BA 46: p=0.010) and MADRS (BA 9: p=0.042; BA 46: p=0.038) scores. Our results do not come out in favor of one or the other BA. Stimulation of BA 9 and BA 46 appears to be equally effective in the treatment of depression. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  12. Diffusion-weighted imaging in fetuses with unilateral cortical malformations and callosal agenesis.

    Science.gov (United States)

    Glenn, O A; Quiroz, E M; Berman, J I; Studholme, C; Xu, D

    2010-06-01

    DWI was performed in fetuses with callosal agenesis and unilateral cortical malformations. ADC values were retrospectively measured in the developing white matter underlying the cortical malformation and compared with the corresponding contralateral white matter. In all 3 patients, ADC values were lower under the areas of cortical malformation compared with the normal contralateral side. Our findings suggest that there are structural differences in the developing white matter underlying areas of cortical malformation.

  13. Dose-Dependent Effects of Theta Burst rTMS on Cortical Excitability and Resting-State Connectivity of the Human Motor System

    Science.gov (United States)

    Nettekoven, Charlotte; Volz, Lukas J.; Kutscha, Martha; Pool, Eva-Maria; Rehme, Anne K.; Eickhoff, Simon B.; Fink, Gereon R.

    2014-01-01

    Theta burst stimulation (TBS), a specific protocol of repetitive transcranial magnetic stimulation (rTMS), induces changes in cortical excitability that last beyond stimulation. TBS-induced aftereffects, however, vary between subjects, and the mechanisms underlying these aftereffects to date remain poorly understood. Therefore, the purpose of this study was to investigate whether increasing the number of pulses of intermittent TBS (iTBS) (1) increases cortical excitability as measured by motor-evoked potentials (MEPs) and (2) alters functional connectivity measured using resting-state fMRI, in a dose-dependent manner. Sixteen healthy, human subjects received three serially applied iTBS blocks of 600 pulses over the primary motor cortex (M1 stimulation) and the parieto-occipital vertex (sham stimulation) to test for dose-dependent iTBS effects on cortical excitability and functional connectivity (four sessions in total). iTBS over M1 increased MEP amplitudes compared with sham stimulation after each stimulation block. Although the increase in MEP amplitudes did not differ between the first and second block of M1 stimulation, we observed a significant increase after three blocks (1800 pulses). Furthermore, iTBS enhanced resting-state functional connectivity between the stimulated M1 and premotor regions in both hemispheres. Functional connectivity between M1 and ipsilateral dorsal premotor cortex further increased dose-dependently after 1800 pulses of iTBS over M1. However, no correlation between changes in MEP amplitudes and functional connectivity was detected. In summary, our data show that increasing the number of iTBS stimulation blocks results in dose-dependent effects at the local level (cortical excitability) as well as at a systems level (functional connectivity) with a dose-dependent enhancement of dorsal premotor cortex-M1 connectivity. PMID:24828639

  14. Synaptic and functional linkages between spinal premotor interneurons and hand-muscle activity during precision grip

    Directory of Open Access Journals (Sweden)

    Tomohiko eTakei

    2013-04-01

    Full Text Available Grasping is a highly complex movement that requires the coordination of a number of hand joints and muscles. Previous studies showed that spinal premotor interneurons (PreM-INs in the primate cervical spinal cord have divergent synaptic effects on hand motoneurons and that they might contribute to hand-muscle synergies. However, the extent to which these PreM-IN synaptic connections functionally contribute to modulating hand-muscle activity is not clear. In this paper, we explored the contribution of spinal PreM-INs to hand-muscle activation by quantifying the synaptic linkage (SL and functional linkage (FL of the PreM-INs with hand-muscle activities. The activity of 23 PreM-INs was recorded from the cervical spinal cord (C6–T1, with EMG signals measured simultaneously from hand and arm muscles in two macaque monkeys performing a precision grip task. Spike-triggered averages (STAs of rectified EMGs were compiled for 456 neuron–muscle pairs; 63 pairs showed significant post-spike effects (i.e., SL. Conversely, 231 of 456 pairs showed significant cross-correlations between the IN firing rate and rectified EMG (i.e., FL. Importantly, a greater proportion of the neuron–muscle pairs with SL showed FL (43/63 pairs, 68% compared with the pairs without SL (203/393, 52%, and the presence of SL was significantly associated with that of FL. However, a significant number of pairs had SL without FL (SL∩!FL, n = 20 or FL without SL (!SL∩FL, n = 203, and the proportions of these incongruities exceeded the number expected by chance. These results suggested that spinal PreM-INs function to significantly modulate hand-muscle activity during precision grip, but the contribution of other neural structures is also needed to recruit an adequate combination of hand-muscle motoneurons.

  15. Cardiovascular physiology in pre-motor Parkinson disease: A Neuroepidemiologic study

    Science.gov (United States)

    Jain, S; Ton, TG; Perera, S; Zheng, Y; Stein, PK; Thacker, EL; Strotmeyer, ES; Newman, AB; Longstreth, WT

    2013-01-01

    Background Changes in cardiovascular physiology in PD are common and may occur prior to diagnostic Parkinsonian motor signs. We investigated associations of electrocardiographic (ECG) abnormalities, orthostasis, heart rate variability or carotid stenosis with the risk of Parkinson disease (PD) diagnosis in the Cardiovascular Health Study, a community-based cohort of older adults. Methods ECG abnormality, orthostasis (symptomatic or asymptomatic), heart rate variability (24-hour Holter monitoring) or any carotid stenosis (≥1%) by ultrasound were modeled as primary predictors for incident PD diagnosis using multivariable logistic regression. Incident PD cases were identified by at least one of the following: self-report, anti-Parkinsonian medication use, or ICD9. If unadjusted models were significant, they were adjusted or stratified for age, sex and smoking status and those in which predictors were still significant (p≤0.05) were additionally adjusted for race, diabetes, total cholesterol, low density lipoprotein, blood pressure, body mass index, physical activity, education level, stroke and C-reactive protein. Results Of 5,888 participants, 154 incident PD cases were identified over 14 years of follow-up. After adjusting models with all covariates, those with any ECG abnormality (Odds Ratio: 1.45, 95% CI: 1.02-2.07,p=0.04) or any carotid stenosis (OR: 2.40, 95% CI (1.40-4.09,p=0.001) at baseline had a higher risk of incident PD diagnosis. Orthostasis and heart rate variability were not significant predictors. Conclusions This exploratory study suggests that carotid stenosis and ECG abnormalities occur prior to motor signs in PD, thus serving as potential pre-motor features or risk factors for PD diagnosis. Replication is needed in a population with more thorough ascertainment of PD onset. PMID:22700356

  16. Interhemispheric interaction between human dorsal premotor and contralateral primary motor cortex.

    Science.gov (United States)

    Mochizuki, Hitoshi; Huang, Ying-Zu; Rothwell, John C

    2004-11-15

    We used transcranial magnetic stimulation (TMS) in a paired pulse protocol to investigate interhemispheric interactions between the right dorsal premotor (dPM) and left primary motor cortex (M1) using interstimulus intervals of 4, 6, 8, 10, 12, 16 and 20 ms in ten healthy subjects. A conditioning stimulus over right dPM at an intensity of either 90 or 110% resting motor threshold (RMT) suppressed motor-evoked potentials (MEPs) evoked in the first dorsal interosseous (FDI) muscle by stimulation of left M1. Maximum effects occurred for interstimulus intervals (ISIs) of 8-10 ms. There was no effect if the conditioning stimulus was applied 2.5 cm lateral, anterior or medial to dPM. The effect differed from previously described M1 interhemispheric inhibition in that the threshold for the latter was greater than 90% RMT, whereas stimulation of the dPM at the same intensity led to significant inhibition. In addition, voluntary contraction of the left FDI (i.e. contralateral to the conditioning TMS) enhanced interhemispheric inhibition from right M1 but had no effect on the inhibition from right dPM. Finally, conditioning to right dPM at 90% RMT reduced short-interval intracortical inhibition (SICI; at ISI = 2 ms) in left M1 whilst there was no effect if the conditioning stimulus was applied to right M1. We conclude that conditioning TMS over dPM has effects that differ from the previous pattern of interhemispheric inhibition described between bilateral M1s. This may reflect the existence of commissural fibres between dPM and contralateral M1 that may play a role in bimanual coordination.

  17. Cortical Network for Reading Linear Words in an Alphasyllabary

    Science.gov (United States)

    Das, Tanusree; Bapi, Raju S.; Padakannaya, Prakash; Singh, Nandini C.

    2011-01-01

    Functional imaging studies have established cortical networks for reading alphabetic, syllabic and logographic scripts. There is little information about the different cortical areas that participate in reading an alphasyllabary. We use functional brain imaging to study the reading network for Devanagari, an alphasyllabary. Similar to syllabic…

  18. Non-primary motor areas in the human frontal lobe are connected directly to hand muscles.

    Science.gov (United States)

    Teitti, S; Määttä, S; Säisänen, L; Könönen, M; Vanninen, R; Hannula, H; Mervaala, E; Karhu, J

    2008-04-15

    Structural studies in primates have shown that, in addition to the primary motor cortex (M1), premotor areas are a source of corticospinal tracts. The function of these putative corticospinal neuronal tracts in humans is still unclear. We found frontal non-primary motor areas (NPMAs), which react to targeted non-invasive magnetic pulses and activate peripheral muscles as fast as or even faster than those in M1. Hand muscle movements were observed in all our subjects about 20 ms after transcranial stimulation of the superior frontal gyrus (Brodmann areas 6 and 8). Stimulation of NPMA could activate both proximal and distal upper limb muscles with the same delay as a stimulation of the M1, indicating converging motor representations with direct functional connections to the hand. We suggest that these non-primary cortical motor representations provide additional capacity for the fast execution of movements. Such a capacity may play a role in motor learning and in recovery from motor deficits.

  19. Differential representation of arm movement direction in relation to cortical anatomy and function

    Science.gov (United States)

    Ball, Tonio; Schulze-Bonhage, Andreas; Aertsen, Ad; Mehring, Carsten

    2009-02-01

    Information about arm movement direction in neuronal activity of the cerebral cortex can be used for movement control mediated by a brain-machine interface (BMI). Here we provide a topographic analysis of the information related to arm movement direction that can be extracted from single trials of electrocorticographic (ECoG) signals recorded from the human frontal and parietal cortex based on a precise assignment of ECoG recording channels to the subjects' individual cortical anatomy and function. To this aim, each electrode contact was identified on structural MRI scans acquired while the electrodes were implanted and was thus related to the brain anatomy of each patient. Cortical function was assessed by direct cortical electrical stimulation. We show that activity from the primary motor cortex, in particular from the region showing hand and arm motor responses upon electrical stimulation, carries most directional information. The premotor, posterior parietal and lateral prefrontal cortex contributed gradually less, but still significant information. This gradient was observed for decoding from movement-related potentials, and from spectral amplitude modulations in low frequencies and in the high gamma band. Our findings thus demonstrate a close topographic correlation between cortical functional anatomy and direction-related information in humans that might be used for brain-machine interfacing.

  20. Cortical activation elicited by unrecognized stimuli

    Directory of Open Access Journals (Sweden)

    Badgaiyan Rajendra D

    2006-05-01

    Full Text Available Abstract Background It is unclear whether a stimulus that cannot be recognized consciously, could elicit a well-processed cognitive response. Methods We used functional imaging to examine the pattern of cortical activation elicited by unrecognized stimuli during memory processing. Subjects were given a recognition task using recognizable and non-recognizable subliminal stimuli. Results Unrecognized stimuli activated the cortical areas that are associated with retrieval attempt (left prefrontal, and novelty detection (left hippocampus. This indicates that the stimuli that were not consciously recognized, activated neural network associated with aspects of explicit memory processing. Conclusion Results suggest that conscious recognition of stimuli is not necessary for activation of cognitive processing.

  1. Quantitative radiology: radiogrammetry of cortical bone.

    Science.gov (United States)

    Dequeker, J

    1976-11-01

    Based on personal experience and data in the literature, an overview is given of radiogrammetry of cortical bone of the second metacarpal. There is a within- and between-observer error which amounts respectively to 1.2 and 1.5% for the outer diameter and 4.8 and 6.4% for the inner diameter. The systematic + or-- trend between observers indicates that one observer working according to certain defined rules obtains the most reliable results. There is a large variability in amount of bone within one age and sex group which is partly due to skeletal size differences, are insufficient since skeletal size differences still exist. The variability is reduced when the data are divided into strata of skeletal size. Since cortical area shows the best correlation with outer diameter within each age group and since cortical area represents best the ash content of the bones the values of this index are most suited to be grouped according to outer diameter. In differentiating pathological from physiological bone loss this procedure is an improvement on the previously published indices of amount of bone. When comparing different populations this method has advantages since skeletal size differences are eliminated. Comparing seven populations it was found that populations living in the United States of America have more bone for a given skeletal size than populations in Europe or Nigeria. Bone loss with age is a general phenomenon but differences in rate of loss are observed between the sexes and between ethnic different populations. The decrease of bone mass is faster after the age of 50 years in woman than in men. Blacks living in the United States loose less bone with age than whites. Radiogrammetry of cortical bone in groups gives useful information on bond remodelling during ageing and in pathological conditions. At an individual level, however, it is difficult to evaluate changes on a short term basis with radiogrammetry. Radiogrammetry of cortical bone is a simple and

  2. Metaphorical motion in mathematical reasoning: further evidence for pre-motor implementation of structure mapping in abstract domains.

    Science.gov (United States)

    Fields, Chris

    2013-08-01

    The theory of computation and category theory both employ arrow-based notations that suggest that the basic metaphor "state changes are like motions" plays a fundamental role in all mathematical reasoning involving formal manipulations. If this is correct, structure-mapping inferences implemented by the pre-motor action planning system can be expected to be involved in solving any mathematics problems not solvable by table lookups and number line manipulations alone. Available functional imaging studies of multi-digit arithmetic, algebra, geometry and calculus problem solving are consistent with this expectation.

  3. Do premotor interneurons act in parallel on spinal motoneurons and on dorsal horn spinocerebellar and spinocervical tract neurons in the cat?

    Science.gov (United States)

    Krutki, Piotr; Jelen, Sabina; Jankowska, Elzbieta

    2011-04-01

    It has previously been established that ventral spinocerebellar tract (VSCT) neurons and dorsal spinocerebellar tract neurons located in Clarke's column (CC DSCT neurons) forward information on actions of premotor interneurons in reflex pathways from muscle afferents on α-motoneurons. Whether DSCT neurons located in the dorsal horn (dh DSCT neurons) and spinocervical tract (SCT) neurons are involved in forwarding similar feedback information has not yet been investigated. The aim of the present study was therefore to examine the input from premotor interneurons to these neurons. Electrical stimuli were applied within major hindlimb motor nuclei to activate axon-collaterals of interneurons projecting to these nuclei, and intracellular records were obtained from dh DSCT and SCT neurons. Direct actions of the stimulated interneurons were differentiated from indirect actions by latencies of postsynaptic potentials evoked by intraspinal stimuli and by the absence or presence of temporal facilitation. Direct actions of premotor interneurons were found in a smaller proportion of dh DSCT than of CC DSCT neurons. However, they were evoked by both excitatory and inhibitory interneurons, whereas only inhibitory premotor interneurons were previously found to affect CC DSCT neurons [as indicated by monosynaptic excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs) in dh DSCT and only IPSPs in CC DSCT neurons]. No effects of premotor interneurons were found in SCT neurons, since monosynaptic EPSPs or IPSPs were only evoked in them by stimuli applied outside motor nuclei. The study thus reveals a considerable differentiation of feedback information provided by different populations of ascending tract neurons.

  4. Caracterização da comunidade liquênica corticícola de Porto Alegre e áreas adjacentes, RS, Brasil Characterization of the corticolous lichen community from Porto Alegre and adjacent areas, RS, Brazil

    Directory of Open Access Journals (Sweden)

    Márcia Isabel Käffer

    2011-12-01

    Full Text Available Liquens são organismos em simbiose que habitam os mais diversos ambientes, entretanto em regiões urbanizadas a comunidade liquênica pode ser modificada devido à influência de fatores antrópicos. O objetivo deste trabalho é analisar a composição da comunidade liquênica corticícola na cidade de Porto Alegre e áreas adjacentes, assim como verificar a freqüência, cobertura e valor de importância dos táxons, apresentando uma chave de identificação para as espécies urbanas. Foram analisadas 300 forófitas distribuídas em 30 estações de amostragem divididas em 33 bairros da cidade. Foram registrados 144 táxons liquênicos com prováveis três novos registros para a ciência e dois novos registros para o Estado do Rio Grande do Sul. As espécies mais importantes na comunidade foram Canoparmelia texana (Tuck. Elix & Hale e Dirinaria picta (Sw. Schaer. ex Clem, as quais apresentaram os maiores valores de importância, freqüência e cobertura. O grande número de táxons encontrados nas áreas analisadas representa uma contribuição significante para as pesquisas na área da liquenologia, principalmente por serem utilizados em programas de monitoramento da qualidade do ar, bem como para avaliar a estrutura de ecossistemas florestais.Lichens are symbiotic organisms found in a variety of habitats; however, in urban areas the lichen community can be altered due to the influence of anthropogenic factors. This study aimed to analyze the corticolous lichen community composition in Porto Alegre and adjacent areas, as well as to investigate the frequency, coverage and importance value of the reported taxa. A key to the urban species is also provided. Three hundred phorophytes distributed in 30 sampling stations, divided among 33 city districts, were analyzed. One hundred and forty-four taxa of lichenized fungi were recorded with three probable new citations for Brazil and two new records for Rio Grande do Sul State. The most important

  5. Extensive cortical remyelination in patients with chronic multiple sclerosis.

    Science.gov (United States)

    Albert, Monika; Antel, Jack; Brück, Wolfgang; Stadelmann, Christine

    2007-04-01

    Recent studies revealed prominent cortical demyelination in patients with chronic multiple sclerosis (MS). Demyelination in white matter lesions is frequently accompanied by remyelination. This repair process, however, often remains incomplete and restricted to the lesion border. In the present study, we examined the frequency and extent of remyelination in cortical and white matter lesions in autopsy brain tissue of 33 patients with chronic MS. The majority of patients (29 of 33) harbored cortical demyelination. Remyelination of cortical lesions was identified light microscopically by the presence of thin and irregularly arranged myelin sheaths, and confirmed by electron microscopy. Extensive remyelination was found in 18%, remyelination restricted to the lesion border in 54%, and no remyelination in 28% of cortical lesions. A direct comparison of the extent of remyelination in white matter and cortical lesions of the same patients revealed that remyelination of cortical lesions was consistently more extensive. In addition, g-ratios of fibers in areas of "normal appearing cortex" yielded values consistent with remyelination. Our data confirm the high prevalence of cortical demyelination in chronic MS and imply that the propensity to remyelinate is high in cortical MS lesions.

  6. Overweight is not associated with cortical thickness alterations in children

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    Rachel Jane Sharkey

    2015-02-01

    Full Text Available IntroductionSeveral studies report an association between body mass index (BMI and cortical thickness in adults. Some studies demonstrate diffuse cortical thinning in obesity, while others report effects in areas that are associated with self-regulation, such as lateral prefrontal cortex. MethodsThis study used multilevel modelling of data from the NIH Pediatric MRI Data Repository, a mixed longitudinal and cross-sectional database, to examine the relationship between cortical thickness and body weight in children. Cortical thickness was computed at 81,942 vertices of 716 MRI scans from 378 children aged between 4 and 18 years. Body mass index Z score for age was computed for each participant. We preformed vertex-wise statistical analysis of the relationship between cortical thickness and BMI, accounting for age and gender. In addition, cortical thickness was extracted from regions of interest in prefrontal cortex and insula.ResultsNo significant association between cortical thickness and BMI was found, either by statistical parametric mapping or by region of interest analysis. Results remained negative when the analysis was restricted to children aged 12-18.ConclusionsThe correlation between BMI and cortical thickness was not found in this large pediatric sample. The association between BMI and cortical thinning develops after adolescence. This has implications for the nature of the relationship between brain anatomy and weight gain.

  7. Cortical myoclonus and cerebellar pathology

    NARCIS (Netherlands)

    Tijssen, MAJ; Thom, M; Ellison, DW; Wilkins, P; Barnes, D; Thompson, PD; Brown, P

    2000-01-01

    Objective To study the electrophysiologic and pathologic findings in three patients with cortical myoclonus. In two patients the myoclonic ataxic syndrome was associated with proven celiac disease. Background: The pathologic findings in conditions associated with cortical myoclonus commonly involve

  8. Cortical Abnormalities in ADHD

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2003-12-01

    Full Text Available Grey-matter abnormalities at the cortical surface and regional brain size were mapped by high-resolution MRI and surface-based, computational image analytical techniques in a group of 27 children and adolescents with attention deficit hyperactivity disorder (ADHD and 46 controls, matched by age and sex, at the University of California at Los Angeles.

  9. Gyrification from constrained cortical expansion

    CERN Document Server

    Tallinen, Tuomas; Biggins, John S; Mahadevan, L

    2015-01-01

    The exterior of the mammalian brain - the cerebral cortex - has a conserved layered structure whose thickness varies little across species. However, selection pressures over evolutionary time scales have led to cortices that have a large surface area to volume ratio in some organisms, with the result that the brain is strongly convoluted into sulci and gyri. Here we show that the gyrification can arise as a nonlinear consequence of a simple mechanical instability driven by tangential expansion of the gray matter constrained by the white matter. A physical mimic of the process using a layered swelling gel captures the essence of the mechanism, and numerical simulations of the brain treated as a soft solid lead to the formation of cusped sulci and smooth gyri similar to those in the brain. The resulting gyrification patterns are a function of relative cortical expansion and relative thickness (compared with brain size), and are consistent with observations of a wide range of brains, ranging from smooth to highl...

  10. Nociceptive afferents to the premotor neurons that send axons simultaneously to the facial and hypoglossal motoneurons by means of axon collaterals.

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    Yulin Dong

    Full Text Available It is well known that the brainstem premotor neurons of the facial nucleus and hypoglossal nucleus coordinate orofacial nociceptive reflex (ONR responses. However, whether the brainstem PNs receive the nociceptive projection directly from the caudal spinal trigeminal nucleus is still kept unclear. Our present study focuses on the distribution of premotor neurons in the ONR pathways of rats and the collateral projection of the premotor neurons which are involved in the brainstem local pathways of the orofacial nociceptive reflexes of rat. Retrograde tracer Fluoro-gold (FG or FG/tetramethylrhodamine-dextran amine (TMR-DA were injected into the VII or/and XII, and anterograde tracer biotinylated dextran amine (BDA was injected into the caudal spinal trigeminal nucleus (Vc. The tracing studies indicated that FG-labeled neurons receiving BDA-labeled fibers from the Vc were mainly distributed bilaterally in the parvicellular reticular formation (PCRt, dorsal and ventral medullary reticular formation (MdD, MdV, supratrigeminal nucleus (Vsup and parabrachial nucleus (PBN with an ipsilateral dominance. Some FG/TMR-DA double-labeled premotor neurons, which were observed bilaterally in the PCRt, MdD, dorsal part of the MdV, peri-motor nucleus regions, contacted with BDA-labeled axonal terminals and expressed c-fos protein-like immunoreactivity which induced by subcutaneous injection of formalin into the lip. After retrograde tracer wheat germ agglutinated horseradish peroxidase (WGA-HRP was injected into VII or XII and BDA into Vc, electron microscopic study revealed that some BDA-labeled axonal terminals made mainly asymmetric synapses on the dendritic and somatic profiles of WGA-HRP-labeled premotor neurons. These data indicate that some premotor neurons could integrate the orofacial nociceptive input from the Vc and transfer these signals simultaneously to different brainstem motonuclei by axonal collaterals.

  11. Purely Cortical Anaplastic Ependymoma

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    Flávio Ramalho Romero

    2012-01-01

    Full Text Available Ependymomas are glial tumors derived from ependymal cells lining the ventricles and the central canal of the spinal cord. It may occur outside the ventricular structures, representing the extraventicular form, or without any relationship of ventricular system, called ectopic ependymona. Less than fifteen cases of ectopic ependymomas were reported and less than five were anaplastic. We report a rare case of pure cortical ectopic anaplastic ependymoma.

  12. [Posterior cortical atrophy].

    Science.gov (United States)

    Solyga, Volker Moræus; Western, Elin; Solheim, Hanne; Hassel, Bjørnar; Kerty, Emilia

    2015-06-02

    Posterior cortical atrophy is a neurodegenerative condition with atrophy of posterior parts of the cerebral cortex, including the visual cortex and parts of the parietal and temporal cortices. It presents early, in the 50s or 60s, with nonspecific visual disturbances that are often misinterpreted as ophthalmological, which can delay the diagnosis. The purpose of this article is to present current knowledge about symptoms, diagnostics and treatment of this condition. The review is based on a selection of relevant articles in PubMed and on the authors' own experience with the patient group. Posterior cortical atrophy causes gradually increasing impairment in reading, distance judgement, and the ability to perceive complex images. Examination of higher visual functions, neuropsychological testing, and neuroimaging contribute to diagnosis. In the early stages, patients do not have problems with memory or insight, but cognitive impairment and dementia can develop. It is unclear whether the condition is a variant of Alzheimer's disease, or whether it is a separate disease entity. There is no established treatment, but practical measures such as the aid of social care workers, telephones with large keypads, computers with voice recognition software and audiobooks can be useful. Currently available treatment has very limited effect on the disease itself. Nevertheless it is important to identify and diagnose the condition in its early stages in order to be able to offer patients practical assistance in their daily lives.

  13. Differences in frontal cortical activation by a working memory task after substitution of risperidone for typical antipsychotic drugs in patients with schizophrenia

    Science.gov (United States)

    Honey, Garry D.; Bullmore, Edward T.; Soni, William; Varatheesan, Malini; Williams, Steve C. R.; Sharma, Tonmoy

    1999-01-01

    Antipsychotic drug treatment of schizophrenia may be complicated by side effects of widespread dopaminergic antagonism, including exacerbation of negative and cognitive symptoms due to frontal cortical hypodopaminergia. Atypical antipsychotics have been shown to enhance frontal dopaminergic activity in animal models. We predicted that substitution of risperidone for typical antipsychotic drugs in the treatment of schizophrenia would be associated with enhanced functional activation of frontal cortex. We measured cerebral blood oxygenation changes during periodic performance of a verbal working memory task, using functional MRI, on two occasions (baseline and 6 weeks later) in two cohorts of schizophrenic patients. One cohort (n = 10) was treated with typical antipsychotic drugs throughout the study. Risperidone was substituted for typical antipsychotics after baseline assessment in the second cohort (n = 10). A matched group of healthy volunteers (n = 10) was also studied on a single occasion. A network comprising bilateral dorsolateral prefrontal and lateral premotor cortex, the supplementary motor area, and posterior parietal cortex was activated by working memory task performance in both the patients and comparison subjects. A two-way analysis of covariance was used to estimate the effect of substituting risperidone for typical antipsychotics on power of functional response in the patient group. Substitution of risperidone increased functional activation in right prefrontal cortex, supplementary motor area, and posterior parietal cortex at both voxel and regional levels of analysis. This study provides direct evidence for significantly enhanced frontal function in schizophrenic patients after substitution of risperidone for typical antipsychotic drugs, and it indicates the potential value of functional MRI as a tool for longitudinal assessment of psychopharmacological effects on cerebral physiology. PMID:10557338

  14. Neural correlates of cognitive impairment in posterior cortical atrophy.

    Science.gov (United States)

    Kas, Aurélie; de Souza, Leonardo Cruz; Samri, Dalila; Bartolomeo, Paolo; Lacomblez, Lucette; Kalafat, Michel; Migliaccio, Raffaella; Thiebaut de Schotten, Michel; Cohen, Laurent; Dubois, Bruno; Habert, Marie-Odile; Sarazin, Marie

    2011-05-01

    With the prospect of disease-modifying drugs that will target the physiopathological process of Alzheimer's disease, it is now crucial to increase the understanding of the atypical focal presentations of Alzheimer's disease, such as posterior cortical atrophy. This study aimed to (i) characterize the brain perfusion profile in posterior cortical atrophy using regions of interest and a voxel-based approach; (ii) study the influence of the disease duration on the clinical and imaging profiles; and (iii) explore the correlations between brain perfusion and cognitive deficits. Thirty-nine patients with posterior cortical atrophy underwent a specific battery of neuropsychological tests, mainly targeting visuospatial functions, and a brain perfusion scintigraphy with 99mTc-ethyl cysteinate dimer. The imaging analysis included a comparison with a group of 24 patients with Alzheimer's disease, matched for age, disease duration and Mini-Mental State Examination, and 24 healthy controls. The single-photon emission computed tomography profile in patients with posterior cortical atrophy was characterized by extensive and severe hypoperfusion in the occipital, parietal, posterior temporal cortices and in a smaller cortical area corresponding to the frontal eye fields (Brodmann areas 6/8). Compared with patients with Alzheimer's disease, the group with posterior cortical atrophy showed more severe occipitoparietal hypoperfusion and higher perfusion in the frontal, anterior cingulate and mesiotemporal regions. When considering the disease duration, the functional changes began and remained centred on the posterior lobes, even in the late stage. Correlation analyses of brain perfusion and neuropsychological scores in posterior cortical atrophy highlighted the prominent role of left inferior parietal damage in acalculia, Gerstmann's syndrome, left-right indistinction and limb apraxia, whereas damage to the bilateral dorsal occipitoparietal regions appeared to be involved in B

  15. Identification of Inhibitory Premotor Interneurons Activated at a Late Phase in a Motor Cycle during Drosophila Larval Locomotion.

    Science.gov (United States)

    Itakura, Yuki; Kohsaka, Hiroshi; Ohyama, Tomoko; Zlatic, Marta; Pulver, Stefan R; Nose, Akinao

    2015-01-01

    Rhythmic motor patterns underlying many types of locomotion are thought to be produced by central pattern generators (CPGs). Our knowledge of how CPG networks generate motor patterns in complex nervous systems remains incomplete, despite decades of work in a variety of model organisms. Substrate borne locomotion in Drosophila larvae is driven by waves of muscular contraction that propagate through multiple body segments. We use the motor circuitry underlying crawling in larval Drosophila as a model to try to understand how segmentally coordinated rhythmic motor patterns are generated. Whereas muscles, motoneurons and sensory neurons have been well investigated in this system, far less is known about the identities and function of interneurons. Our recent study identified a class of glutamatergic premotor interneurons, PMSIs (period-positive median segmental interneurons), that regulate the speed of locomotion. Here, we report on the identification of a distinct class of glutamatergic premotor interneurons called Glutamatergic Ventro-Lateral Interneurons (GVLIs). We used calcium imaging to search for interneurons that show rhythmic activity and identified GVLIs as interneurons showing wave-like activity during peristalsis. Paired GVLIs were present in each abdominal segment A1-A7 and locally extended an axon towards a dorsal neuropile region, where they formed GRASP-positive putative synaptic contacts with motoneurons. The interneurons expressed vesicular glutamate transporter (vGluT) and thus likely secrete glutamate, a neurotransmitter known to inhibit motoneurons. These anatomical results suggest that GVLIs are premotor interneurons that locally inhibit motoneurons in the same segment. Consistent with this, optogenetic activation of GVLIs with the red-shifted channelrhodopsin, CsChrimson ceased ongoing peristalsis in crawling larvae. Simultaneous calcium imaging of the activity of GVLIs and motoneurons showed that GVLIs' wave-like activity lagged behind that of

  16. Identification of Inhibitory Premotor Interneurons Activated at a Late Phase in a Motor Cycle during Drosophila Larval Locomotion.

    Directory of Open Access Journals (Sweden)

    Yuki Itakura

    Full Text Available Rhythmic motor patterns underlying many types of locomotion are thought to be produced by central pattern generators (CPGs. Our knowledge of how CPG networks generate motor patterns in complex nervous systems remains incomplete, despite decades of work in a variety of model organisms. Substrate borne locomotion in Drosophila larvae is driven by waves of muscular contraction that propagate through multiple body segments. We use the motor circuitry underlying crawling in larval Drosophila as a model to try to understand how segmentally coordinated rhythmic motor patterns are generated. Whereas muscles, motoneurons and sensory neurons have been well investigated in this system, far less is known about the identities and function of interneurons. Our recent study identified a class of glutamatergic premotor interneurons, PMSIs (period-positive median segmental interneurons, that regulate the speed of locomotion. Here, we report on the identification of a distinct class of glutamatergic premotor interneurons called Glutamatergic Ventro-Lateral Interneurons (GVLIs. We used calcium imaging to search for interneurons that show rhythmic activity and identified GVLIs as interneurons showing wave-like activity during peristalsis. Paired GVLIs were present in each abdominal segment A1-A7 and locally extended an axon towards a dorsal neuropile region, where they formed GRASP-positive putative synaptic contacts with motoneurons. The interneurons expressed vesicular glutamate transporter (vGluT and thus likely secrete glutamate, a neurotransmitter known to inhibit motoneurons. These anatomical results suggest that GVLIs are premotor interneurons that locally inhibit motoneurons in the same segment. Consistent with this, optogenetic activation of GVLIs with the red-shifted channelrhodopsin, CsChrimson ceased ongoing peristalsis in crawling larvae. Simultaneous calcium imaging of the activity of GVLIs and motoneurons showed that GVLIs' wave-like activity lagged

  17. Slowly progressive anarthria with late anterior opercular syndrome: a variant form of frontal cortical atrophy syndromes.

    Science.gov (United States)

    Broussolle, E; Bakchine, S; Tommasi, M; Laurent, B; Bazin, B; Cinotti, L; Cohen, L; Chazot, G

    1996-12-01

    We describe eight patients with slowly progressive speech production deficit combining speech apraxia, dysarthria, dysprosody and orofacial apraxia, and initially no other deficit in other language and non-language neuropsychological domains. Long-term follow-up (6-10 years) in 4 cases showed an evolution to muteness, bilateral suprabulbar paresis with automatic-voluntary dissociation and frontal lobe cognitive slowing without generalised intellectual deterioration. Most disabled patients presented with an anterior opercular syndrome (Foix-Chavany-Marie syndrome), and pyramidal or extrapyramidal signs. CT and MRI findings disclosed asymmetric (left > right) progressive cortical atrophy of the frontal lobes predominating in the posterior inferior frontal region, notably the operculum. SPECT and PET revealed a decreased cerebral blood flow and metabolism, prominent in the left posterior-inferior frontal gyrus and premotor cortex, extending bilaterally in the most advanced cases. Pathological study of two cases showed non-specific neuronal loss, gliosis, and spongiosis of superficial cortical layers, mainly confined to the frontal lobes, with no significant abnormalities in the basal ganglia, thalamus, cerebellum, brain stem (except severe neuronal loss in the substantia nigra in one case), and spinal cord. We propose to call this peculiar syndrome Slowly Progressive Anarthria (SPA), based on its specific clinical presentation, and its metabolic and pathological correlates. SPA represents another clinical expression of focal cortical degeneration syndromes, that may overlap with other similar syndromes, specially primary progressive aphasia and the various frontal lobe dementias.

  18. Cortical inactivation by cooling in small animals

    Directory of Open Access Journals (Sweden)

    Ben eCoomber

    2011-06-01

    Full Text Available Reversible inactivation of the cortex by surface cooling is a powerful method for studying the function of a particular area. Implanted cooling cryoloops have been used to study the role of individual cortical areas in auditory processing of awake-behaving cats. Cryoloops have also been used in rodents for reversible inactivation of the cortex, but recently there has been a concern that the cryoloop may also cool non-cortical structures either directly or via the perfusion of blood, cooled as it passed close to the cooling loop. In this study we have confirmed that the loop can inactivate most of the auditory cortex without causing a significant reduction in temperature of the auditory thalamus or other sub-cortical structures. We placed a cryoloop on the surface of the guinea pig cortex, cooled it to 2°C and measured thermal gradients across the neocortical surface. We found that the temperature dropped to 20-24°C among cells within a radius of about 2.5mm away from the loop. This temperature drop was sufficient to reduce activity of most cortical cells and led to the inactivation of almost the entire auditory region. When the temperature of thalamus, midbrain, and middle ear were measured directly during cortical cooling, there was a small drop in temperature (about 4°C but this was not sufficient to directly reduce neural activity. In an effort to visualise the extent of neural inactivation we measured the uptake of thallium ions following an intravenous injection. This confirmed that there was a large reduction of activity across much of the ipsilateral cortex and only a small reduction in subcortical structures.

  19. Cortical control of anticipatory postural adjustments prior to stepping.

    Science.gov (United States)

    Varghese, J P; Merino, D M; Beyer, K B; McIlroy, W E

    2016-01-28

    Human bipedal balance control is achieved either reactively or predictively by a distributed network of neural areas within the central nervous system with a potential role for cerebral cortex. While the role of the cortex in reactive balance has been widely explored, only few studies have addressed the cortical activations related to predictive balance control. The present study investigated the cortical activations related to the preparation and execution of anticipatory postural adjustment (APA) that precede a step. This study also examined whether the preparatory cortical activations related to a specific movement is dependent on the context of control (postural component vs. focal component). Ground reaction forces and electroencephalographic (EEG) data were recorded from 14 healthy adults while they performed lateral weight shift and lateral stepping with and without initially preloading their weight to the stance leg. EEG analysis revealed that there were distinct movement-related potentials (MRPs) with concurrent event-related desynchronization (ERD) of mu and beta rhythms prior to the onset of APA and also to the onset of foot-off during lateral stepping in the fronto-central cortical areas. Also, the MRPs and ERD prior to the onset of APA and onset of lateral weight shift were not significantly different suggesting the comparable cortical activations for the generation of postural and focal movements. The present study reveals the occurrence of cortical activation prior to the execution of an APA that precedes a step. Importantly, this cortical activity appears independent of the context of the movement.

  20. Perceptual incongruence influences bistability and cortical activation.

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    Gijs Joost Brouwer

    Full Text Available We employed a parametric psychophysical design in combination with functional imaging to examine the influence of metric changes in perceptual incongruence on perceptual alternation rates and cortical responses. Subjects viewed a bistable stimulus defined by incongruent depth cues; bistability resulted from incongruence between binocular disparity and monocular perspective cues that specify different slants (slant rivalry. Psychophysical results revealed that perceptual alternation rates were positively correlated with the degree of perceived incongruence. Functional imaging revealed systematic increases in activity that paralleled the psychophysical results within anterior intraparietal sulcus, prior to the onset of perceptual alternations. We suggest that this cortical activity predicts the frequency of subsequent alternations, implying a putative causal role for these areas in initiating bistable perception. In contrast, areas implicated in form and depth processing (LOC and V3A were sensitive to the degree of slant, but failed to show increases in activity when these cues were in conflict.

  1. A change in injured corticospinal tract originating from the premotor cortex to the primary motor cortex in a patient with intracerebral hemorrhage

    Institute of Scientific and Technical Information of China (English)

    Sang Seok Yeo; Sung Ho Jang

    2012-01-01

    Many studies have attempted to elucidate the motor recovery mechanism of stroke, but the majority of these studies focus on cerebral infarct and relatively little is known about the motor recovery mechanism of intracerebral hemorrhage. In this study, we report on a patient with intracerebral hemorrhage who displayed a change in injured corticospinal tract originating from the premotor cortex to the primary motor cortex on diffusion tensor imaging. An 86-year-old woman presented with complete paralysis of the right extremities following spontaneous intracerebral hemorrhage in the left frontoparietal cortex. The patient showed motor recovery, to the extent of being able to extend affected fingers against gravity and to walk independently on even ground at 5 months after onset. Diffusion tensor imaging showed that the left corticospinal tract originated from the premotor cortex at 1 month after intracerebral hemorrhage and from the left primary motor cortex and premotor cortex at 5 months after intracerebral hemorrhage. The change of injured corticospinal tract originating from the premotor cortex to the primary motor cortex suggests motor recovery of intracerebral hemorrhage.

  2. Cortical Thickness Changes Associated with Photoparoxysmal Response

    DEFF Research Database (Denmark)

    Hanganu, Alexandru; Groppa, Stanislav A; Deuschl, Günther

    2014-01-01

    Photoparoxysmal response (PPR) is an EEG trait of spike and spike-wave discharges in response to photic stimulation that is closely linked to idiopathic generalized epilepsy (IGE). In our previous studies we showed that PPR is associated with functional alterations in the occipital and frontal co......) and compared these groups with a group of PPR-negative-healthy-controls (HC, n = 17; 15.3 ± 3.6 years; 6 males). Our results revealed an increase of cortical thickness in the occipital, frontal and parietal cortices bilaterally in PPR-positive-subjects in comparison to HC. Moreover PPR......-positive-subjects presented a significant decrease of cortical thickness in the temporal cortex in the same group contrast. IGE patients exhibited lower cortical thickness in the temporal lobe bilaterally and in the right paracentral region in comparison to PPR-positive-subjects. Our study demonstrates structural changes...... in the occipital lobe, frontoparietal regions and temporal lobe, which also show functional changes associated with PPR. Patients with epilepsy present changes in the temporal lobe and supplementary motor area....

  3. Effects of SR141716A on Cognitive and Depression-Related Behavior in an Animal Model of Premotor Parkinson's Disease

    Directory of Open Access Journals (Sweden)

    M. T. Tadaiesky

    2010-01-01

    Full Text Available A previous study from our laboratory revealed that moderate nigral dopaminergic degeneration caused emotional and cognitive deficits in rats, paralleling early signs of Parkinson's disease. Recent evidence suggests that the blockade of cannabinoid CB1 receptors might be beneficial to alleviate motor inhibition typical of Parkinson's disease. Here, we investigated whether antagonism of CB1 receptors would improve emotional and cognitive deficits in a rat model of premotor Parkinson's disease. Depression-like behavior and cognition were assessed with the forced swim test and the social recognition test, respectively. Confirming our previous study, rats injected with 6-hydroxydopamine in striatum presented emotional and cognitive alterations which were improved by acute injection of SR141716A. HPLC analysis of monoamine levels demonstrated alterations in the striatum and prefrontal cortex after SR141716A injection. These findings suggest a role for CB1 receptors in the early symptoms caused by degeneration of dopaminergic neurons in the striatum, as observed in Parkinson's disease.

  4. Testing the Role of Dorsal Premotor Cortex in Auditory-Motor Association Learning Using Transcranical Magnetic Stimulation (TMS)

    Science.gov (United States)

    Lega, Carlotta; Stephan, Marianne A.; Zatorre, Robert J.; Penhune, Virginia

    2016-01-01

    Interactions between the auditory and the motor systems are critical in music as well as in other domains, such as speech. The premotor cortex, specifically the dorsal premotor cortex (dPMC), seems to play a key role in auditory-motor integration, and in mapping the association between a sound and the movement used to produce it. In the present studies we tested the causal role of the dPMC in learning and applying auditory-motor associations using 1 Hz repetitive Transcranical Magnetic Stimulation (rTMS). In this paradigm, non-musicians learn a set of auditory-motor associations through melody training in two contexts: first when the sound to key-press mapping was in a conventional sequential order (low to high tones mapped onto keys from left to right), and then when it was in a novel scrambled order. Participant’s ability to match the four pitches to four computer keys was tested before and after the training. In both experiments, the group that received 1 Hz rTMS over the dPMC showed no significant improvement on the pitch-matching task following training, whereas the control group (who received rTMS to visual cortex) did. Moreover, in Experiment 2 where the pitch-key mapping was novel, rTMS over the dPMC also interfered with learning. These findings suggest that rTMS over dPMC disturbs the formation of auditory-motor associations, especially when the association is novel and must be learned rather explicitly. The present results contribute to a better understanding of the role of dPMC in auditory-motor integration, suggesting a critical role of dPMC in learning the link between an action and its associated sound. PMID:27684369

  5. Time-coherent expansion of MEG/EEG cortical sources.

    Science.gov (United States)

    David, Olivier; Garnero, Line

    2002-11-01

    In this study we estimated the spatial extent of cortical areas of time-coherent activity using the inverse problem in magneto/electroencephalography (MEEG). The model discussed here uses classical regularization tools in order to force the inverse solution to be piecewise coherent. First, the cortex was seeded by focal dipolar sources. Then, a time-coherent expansion (TCE) onto the cortical surface was performed in order to obtain surface source models composed of patches with uniform current density. Patches represent extended cortical regions with one single time course per active area. Results obtained from synthetic data show that using the TCE method is relevant even with a low signal-to-noise ratio, although the final estimation is often slightly biased. We applied the TCE method to evoked magnetic fields obtained after electrical stimulation of fingers in order to estimate the somatotopic cortical maps of the primary somatosensory cortex.

  6. Individual premotor drive pulses, not time-varying synergies, are the units of adjustment for limb trajectories constructed in spinal cord.

    Science.gov (United States)

    Kargo, William J; Giszter, Simon F

    2008-03-05

    Complex actions may arise by combining simple motor primitives. Our studies support individual premotor drive pulses or bursts as execution primitives in spinal cord. Alternatively, the fundamental execution primitives at the segmental level could be time-varying synergies. To distinguish these hypotheses, we examined sensory feedback effects during targeted wiping organized in spinal cord. This behavior comprises three bursts. We tested (1) whether feedback altered the structure of individual premotor drive bursts or primitives, and (2) whether feedback differentially modulated different drive bursts or pulses in the three burst sequence. At least two of the three bursts would need to always be comodulated to support a time-varying synergy. We used selective muscle vibration to control spindle feedback from a single muscle (biceps/iliofibularis). The structures of premotor drive bursts were conserved. However, biceps vibration (1) scaled the amplitudes of two bursts coactivated during the initial phase of wiping independently of one another without altering their phase, and (2) independently phase regulated the third burst but preserved its amplitude. Thus, all three bursts were regulated separately. Durations were unaffected. The independent effects depended on (1) time of vibration during wiping, (2) frequency of vibration, and (3) limb configuration. Because each of the three bursts was independently modulated, these data strongly support execution using individual premotor bursts rather than time-varying synergies at the spinal level of motor organization. Our data show that both sensory feedback and central systems of the spinal cord act in concert to adjust the individual premotor bursts in support of the straight and unimodal wiping trajectory.

  7. Compensatory activity in the extrastriate body area of Parkinson's disease patients.

    Science.gov (United States)

    van Nuenen, Bart F L; Helmich, Rick C; Buenen, Noud; van de Warrenburg, Bart P C; Bloem, Bastiaan R; Toni, Ivan

    2012-07-11

    Compensatory mechanisms are a crucial component of the cerebral changes triggered by neurodegenerative disorders. Identifying such compensatory mechanisms requires at least two complementary approaches: localizing candidate areas using functional imaging, and showing that interference with these areas has behavioral consequences. Building on recent imaging evidence, we use this approach to test whether a visual region in the human occipito-temporal cortex-the extrastriate body area-compensates for altered dorsal premotor activity in Parkinson's disease (PD) during motor-related processes. We separately inhibited the extrastriate body area and dorsal premotor cortex in 11 PD patients and 12 healthy subjects, using continuous theta burst stimulation. Our goal was to test whether these areas are involved in motor compensatory processes. We used motor imagery to isolate a fundamental element of motor planning, namely subjects' ability to incorporate the current state of their body into a motor plan (mental hand rotation). We quantified this ability through a posture congruency effect (i.e., the improvement in subjects' performance when their current body posture is congruent to the imagined movement). Following inhibition of the right extrastriate body area, the posture congruency effect was lost in PD patients, but not in healthy subjects. In contrast, inhibition of the left dorsal premotor cortex reduced the posture congruency effect in healthy subjects, but not in PD patients. These findings suggest that the right extrastriate body area plays a compensatory role in PD by supporting a function that is no longer performed by the dorsal premotor cortex.

  8. Early development of synchrony in cortical activations in the human.

    Science.gov (United States)

    Koolen, N; Dereymaeker, A; Räsänen, O; Jansen, K; Vervisch, J; Matic, V; Naulaers, G; De Vos, M; Van Huffel, S; Vanhatalo, S

    2016-05-13

    Early intermittent cortical activity is thought to play a crucial role in the growth of neuronal network development, and large scale brain networks are known to provide the basis for higher brain functions. Yet, the early development of the large scale synchrony in cortical activations is unknown. Here, we tested the hypothesis that the early intermittent cortical activations seen in the human scalp EEG show a clear developmental course during the last trimester of pregnancy, the period of intensive growth of cortico-cortical connections. We recorded scalp EEG from altogether 22 premature infants at post-menstrual age between 30 and 44 weeks, and the early cortical synchrony was quantified using recently introduced activation synchrony index (ASI). The developmental correlations of ASI were computed for individual EEG signals as well as anatomically and mathematically defined spatial subgroups. We report two main findings. First, we observed a robust and statistically significant increase in ASI in all cortical areas. Second, there were significant spatial gradients in the synchrony in fronto-occipital and left-to-right directions. These findings provide evidence that early cortical activity is increasingly synchronized across the neocortex. The ASI-based metrics introduced in our work allow direct translational comparison to in vivo animal models, as well as hold promise for implementation as a functional developmental biomarker in future research on human neonates.

  9. Evaluating mandibular cortical index quantitatively.

    Science.gov (United States)

    Yasar, Fusun; Akgunlu, Faruk

    2008-10-01

    The aim was to assess whether Fractal Dimension and Lacunarity analysis can discriminate patients having different mandibular cortical shape. Panoramic radiographs of 52 patients were evaluated for mandibular cortical index. Weighted Kappa between the observations were varying between 0.718-0.805. These radiographs were scanned and converted to binary images. Fractal Dimension and Lacunarity were calculated from the regions where best represents the cortical morphology. It was found that there were statistically significant difference between the Fractal Dimension and Lacunarity of radiographs which were classified as having Cl 1 and Cl 2 (Fractal Dimension P:0.000; Lacunarity P:0.003); and Cl 1 and Cl 3 cortical morphology (Fractal Dimension P:0.008; Lacunarity P:0.001); but there was no statistically significant difference between Fractal Dimension and Lacunarity of radiographs which were classified as having Cl 2 and Cl 3 cortical morphology (Fractal Dimension P:1.000; Lacunarity P:0.758). FD and L can differentiate Cl 1 mandibular cortical shape from both Cl 2 and Cl 3 mandibular cortical shape but cannot differentiate Cl 2 from Cl 3 mandibular cortical shape on panoramic radiographs.

  10. Serotonin modulation of cortical neurons and networks

    Directory of Open Access Journals (Sweden)

    Pau eCelada

    2013-04-01

    Full Text Available The serotonergic pathways originating in the dorsal and median raphe nuclei (DR and MnR, respectively are critically involved in cortical function. Serotonin (5-HT, acting on postsynaptic and presynaptic receptors, is involved in cognition, mood, impulse control and motor functions by 1 modulating the activity of different neuronal types, and 2 varying the release of other neurotransmitters, such as glutamate, GABA, acetylcholine and dopamine. Also, 5-HT seems to play an important role in cortical development. Of all cortical regions, the frontal lobe is the area most enriched in serotonergic axons and 5-HT receptors. 5-HT and selective receptor agonists modulate the excitability of cortical neurons and their discharge rate through the activation of several receptor subtypes, of which the 5-HT1A, 5-HT1B, 5-HT2A and 5-HT3 subtypes play a major role. Little is known, however, on the role of other excitatory receptors moderately expressed in cortical areas, such as 5-HT2C, 5-HT4, 5-HT6 and 5-HT7. In vitro and in vivo studies suggest that 5-HT1A and 5-HT2A receptors are key players and exert opposite effects on the activity of pyramidal neurons in the medial prefrontal cortex (mPFC. The activation of 5-HT1A receptors in mPFC hyperpolarizes pyramidal neurons whereas that of 5-HT2A receptors results in neuronal depolarization, reduction of the afterhyperpolarization and increase of excitatory postsynaptic currents (EPSCs and of discharge rate. 5-HT can also stimulate excitatory (5-HT2A and 5-HT3 and inhibitory (5-HT1A receptors in GABA interneurons to modulate synaptic GABA inputs onto pyramidal neurons. Likewise, the pharmacological manipulation of various 5-HT receptors alters oscillatory activity in PFC, suggesting that 5-HT is also involved in the control of cortical network activity. A better understanding of the actions of 5-HT in PFC may help to develop treatments for mood and cognitive disorders associated with an abnormal function of the

  11. Modeling cortical circuits.

    Energy Technology Data Exchange (ETDEWEB)

    Rohrer, Brandon Robinson; Rothganger, Fredrick H.; Verzi, Stephen J.; Xavier, Patrick Gordon

    2010-09-01

    The neocortex is perhaps the highest region of the human brain, where audio and visual perception takes place along with many important cognitive functions. An important research goal is to describe the mechanisms implemented by the neocortex. There is an apparent regularity in the structure of the neocortex [Brodmann 1909, Mountcastle 1957] which may help simplify this task. The work reported here addresses the problem of how to describe the putative repeated units ('cortical circuits') in a manner that is easily understood and manipulated, with the long-term goal of developing a mathematical and algorithmic description of their function. The approach is to reduce each algorithm to an enhanced perceptron-like structure and describe its computation using difference equations. We organize this algorithmic processing into larger structures based on physiological observations, and implement key modeling concepts in software which runs on parallel computing hardware.

  12. Cortical and spinal assessment

    DEFF Research Database (Denmark)

    Fischer, I W; Gram, Mikkel; Hansen, T M

    2017-01-01

    BACKGROUND: Standardized objective methods to assess the analgesic effects of opioids, enable identification of underlying mechanisms of drug actions in the central nervous system. Opioids may exert their effect on both cortical and spinal levels. In this study actions of morphine at both levels...... subjects was included in the data analysis. There was no change in the activity in resting EEG (P>0.05) after morphine administration as compared to placebo. During cold pressor stimulation, morphine significantly lowered the relative activity in the delta (1-4Hz) band (P=0.03) and increased the activity...... morphine administration (P>0.05). CONCLUSIONS: Cold pressor EEG and the nociceptive reflex were more sensitive to morphine analgesia than resting EEG and can be used as standardized objective methods to assess opioid effects. However, no correlation between the analgesic effect of morphine on the spinal...

  13. Hiperostosis cortical infantil

    OpenAIRE

    Salvador Javier Santos Medina; Orelvis Pérez Duerto

    2015-01-01

    La enfermedad de Caffey, o hiperostosis cortical infantil, es una rara enfermedad ósea autolimitada, que aparece de preferencia en lactantes con signos inespecíficos sistémicos; el más relevante es la reacción subperióstica e hiperostosis en varios huesos del cuerpo, con predilección en el 75-80 % de los casos por la mandíbula. Su pronóstico es bueno, la mayoría no deja secuelas. El propósito del presente trabajo es describir las características clínicas, presentes en un lactante de cinco mes...

  14. Progressive posterior cortical dysfunction

    Directory of Open Access Journals (Sweden)

    Fábio Henrique de Gobbi Porto

    Full Text Available Abstract Progressive posterior cortical dysfunction (PPCD is an insidious syndrome characterized by prominent disorders of higher visual processing. It affects both dorsal (occipito-parietal and ventral (occipito-temporal pathways, disturbing visuospatial processing and visual recognition, respectively. We report a case of a 67-year-old woman presenting with progressive impairment of visual functions. Neurologic examination showed agraphia, alexia, hemispatial neglect (left side visual extinction, complete Balint's syndrome and visual agnosia. Magnetic resonance imaging showed circumscribed atrophy involving the bilateral parieto-occipital regions, slightly more predominant to the right . Our aim was to describe a case of this syndrome, to present a video showing the main abnormalities, and to discuss this unusual presentation of dementia. We believe this article can contribute by improving the recognition of PPCD.

  15. Cortical plasticity and rehabilitation.

    Science.gov (United States)

    Moucha, Raluca; Kilgard, Michael P

    2006-01-01

    The brain is constantly adapting to environmental and endogenous changes (including injury) that occur at every stage of life. The mechanisms that regulate neural plasticity have been refined over millions of years. Motivation and sensory experience directly shape the rewiring that makes learning and neurological recovery possible. Guiding neural reorganization in a manner that facilitates recovery of function is a primary goal of neurological rehabilitation. As the rules that govern neural plasticity become better understood, it will be possible to manipulate the sensory and motor experience of patients to induce specific forms of plasticity. This review summarizes our current knowledge regarding factors that regulate cortical plasticity, illustrates specific forms of reorganization induced by control of each factor, and suggests how to exploit these factors for clinical benefit.

  16. Massive cortical reorganization in sighted Braille readers.

    Science.gov (United States)

    Siuda-Krzywicka, Katarzyna; Bola, Łukasz; Paplińska, Małgorzata; Sumera, Ewa; Jednoróg, Katarzyna; Marchewka, Artur; Śliwińska, Magdalena W; Amedi, Amir; Szwed, Marcin

    2016-03-15

    The brain is capable of large-scale reorganization in blindness or after massive injury. Such reorganization crosses the division into separate sensory cortices (visual, somatosensory...). As its result, the visual cortex of the blind becomes active during tactile Braille reading. Although the possibility of such reorganization in the normal, adult brain has been raised, definitive evidence has been lacking. Here, we demonstrate such extensive reorganization in normal, sighted adults who learned Braille while their brain activity was investigated with fMRI and transcranial magnetic stimulation (TMS). Subjects showed enhanced activity for tactile reading in the visual cortex, including the visual word form area (VWFA) that was modulated by their Braille reading speed and strengthened resting-state connectivity between visual and somatosensory cortices. Moreover, TMS disruption of VWFA activity decreased their tactile reading accuracy. Our results indicate that large-scale reorganization is a viable mechanism recruited when learning complex skills.

  17. Patterns of cortical thinning in nondemented Parkinson's disease patients

    Science.gov (United States)

    Uribe, Carme; Segura, Barbara; Baggio, Hugo Cesar; Abos, Alexandra; Marti, Maria Jose; Valldeoriola, Francesc; Compta, Yaroslau; Bargallo, Nuria

    2016-01-01

    ABSTRACT Background Clinical variability in the Parkinson's disease phenotype suggests the existence of disease subtypes. We investigated whether distinct anatomical patterns of atrophy can be identified in Parkinson's disease using a hypothesis‐free, data‐driven approach based on cortical thickness data. Methods T1‐weighted 3‐tesla MRI and a comprehensive neuropsychological assessment were performed in a sample of 88 nondemented Parkinson's disease patients and 31 healthy controls. We performed a hierarchical cluster analysis of imaging data using Ward's linkage method. A general linear model with cortical thickness data was used to compare clustering groups. Results We observed 3 patterns of cortical thinning in patients when compared with healthy controls. Pattern 1 (n = 30, 34.09%) consisted of cortical atrophy in bilateral precentral gyrus, inferior and superior parietal lobules, cuneus, posterior cingulate, and parahippocampal gyrus. These patients showed worse cognitive performance when compared with controls and the other 2 patterns. Pattern 2 (n = 29, 32.95%) consisted of cortical atrophy involving occipital and frontal as well as superior parietal areas and included patients with younger age at onset. Finally, in pattern 3 (n = 29, 32.95%), there was no detectable cortical thinning. Patients in the 3 patterns did not differ in disease duration, motor severity, dopaminergic medication doses, or presence of mild cognitive impairment. Conclusions Three cortical atrophy subtypes were identified in nondemented Parkinson's disease patients: (1) parieto‐temporal pattern of atrophy with worse cognitive performance, (2) occipital and frontal cortical atrophy and younger disease onset, and (3) patients without detectable cortical atrophy. These findings may help identify prognosis markers in Parkinson's disease. © 2016 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement

  18. Attention-dependent early cortical suppression contributes to crowding.

    Science.gov (United States)

    Chen, Juan; He, Yingchen; Zhu, Ziyun; Zhou, Tiangang; Peng, Yujia; Zhang, Xilin; Fang, Fang

    2014-08-01

    Crowding, the identification difficulty for a target in the presence of nearby flankers, is ubiquitous in spatial vision and is considered a bottleneck of object recognition and visual awareness. Despite its significance, the neural mechanisms of crowding are still unclear. Here, we performed event-related potential and fMRI experiments to measure the cortical interaction between the target and flankers in human subjects. We found that the magnitude of the crowding effect was closely associated with an early suppressive cortical interaction. The cortical suppression was reflected in the earliest event-related potential component (C1), which originated in V1, and in the BOLD signal in V1, but not other higher cortical areas. Intriguingly, spatial attention played a critical role in the manifestation of the suppression. These findings provide direct and converging evidence that attention-dependent V1 suppression contributes to crowding at a very early stage of visual processing.

  19. Selective impairment of verb processing associated with pathological changes in Brodmann areas 44 and 45 in the motor neurone disease-dementia-aphasia syndrome.

    Science.gov (United States)

    Bak, T H; O'Donovan, D G; Xuereb, J H; Boniface, S; Hodges, J R

    2001-01-01

    We report six patients with clinically diagnosed and electrophysiologically confirmed motor neurone disease (MND), in whom communication problems were an early and dominant feature. All patients developed a progressive non-fluent aphasia culminating in some cases in complete mutism. In five cases, formal testing revealed deficits in syntactic comprehension. Comprehension and production of verbs were consistently more affected those that of nouns and this effect remained stable upon subsequent testing, despite overall deterioration. The classical signs of MND, including wasting, fasciculations and severe bulbar symptoms, occurred over the following 6-12 months. The behavioural symptoms ranged from mild anosognosia to personality change implicating frontal-lobe dementia. In three cases, post-mortem examination has confirmed the clinical diagnosis of MND-dementia. In addition to the typical involvement of motor and premotor cortex, particularly pronounced pathological changes were observed in the Brodmann areas 44 (Broca's area) and 45. The finding of a selective impairment of verb/action processing in association with the dementia/aphasia syndrome of MND suggests that the neural substrate underlying verb representation is strongly connected to anterior cortical motor systems.

  20. Parkinson disease and sleep: sleep-wake changes in the premotor stage of Parkinson disease; impaired olfaction and other prodromal features.

    Science.gov (United States)

    Iranzo, Alex

    2013-09-01

    Parkinson disease (PD) has a premotor stage where neurodegeneration occurs before parkinsonism becomes apparent. Identification of individuals at this stage provides an opportunity to study early disease progression and test disease-modifying interventions. Hyposmia, constipation, depression and hypersomnia are part of this premotor phase and predictive of future development of PD. However, these features are common in the general population, and they are most often the result of causes other than incipient PD. In contrast, most individuals with idiopathic REM sleep behavior disorder (IRBD) eventually develop PD and other synucleinopathies. IRBD individuals with hyposmia, substantia nigra hyperechogenicity, and abnormal striatal dopamine transporter imaging findings have increased short-term risk of developing a synucleinopathy. IRBD is an optimal target to test disease-modifying agents in the PD prodromal phase. Serial dopamine transporter imaging, but not olfactory tests, may serve to monitor the disease process in future disease-modifying trials in IRBD.

  1. The Estimation of Cortical Activity for Brain-Computer Interface: Applications in a Domotic Context

    OpenAIRE

    Babiloni, F.; Cincotti, F; M. Marciani; Salinari, S.; Astolfi, L.; A. Tocci; Aloise, F.; De Mattia, D.; De Vico Fallani, F.; Bufalari, S.

    2007-01-01

    In order to analyze whether the use of the cortical activity, estimated from noninvasive EEG recordings, could be useful to detect mental states related to the imagination of limb movements, we estimate cortical activity from high-resolution EEG recordings in a group of healthy subjects by using realistic head models. Such cortical activity was estimated in region of interest associated with the subject's Brodmann areas by using a depth-weighted minimum norm...

  2. Motor cortical organization in an adult with hemimegalencephaly and late onset epilepsy.

    Science.gov (United States)

    Civardi, Carlo; Vicentini, Roberta; Collini, Alessandra; Boccagni, Cristina; Cantello, Roberto; Monaco, Francesco

    2009-08-28

    Hemimegalencephaly is a rare brain malformation whose physiology is largely obscure. In a single patient, we studied motor cortex using several transcranial magnetic stimulation variables testing cortical excitability, and mapping motor area. The megalencephalic hemisphere showed an enlargement of cortical motor map with abnormal axonal orientation and an excess spread of corticospinal excitation, associated with multiple defects of cortical inhibition. TMS gave new information on the anatomic/functional features and epileptogenesis in this complex and physiologically obscure syndrome.

  3. Extroversion-related differences in speed of premotor and motor processing as revealed by lateralized readiness potentials.

    Science.gov (United States)

    Stahl, Jutta; Rammsayer, Thomas

    2008-03-01

    To further elucidate extroversion-related differences in speed of sensorimotor processing, the authors obtained behavioral and psychophysiological measures as participants (16 introverts and 16 extroverts) performed a visual go/no-go task. Although no extroversion-related differences in reaction time emerged, introverts showed faster premotor processing but slower central and peripheral motor processing--as indicated by latencies of the lateralized readiness potential (LRP) and electromyographic (EMG) data, respectively--than extroverts did. Additional regression analyses revealed that stimulus-locked LRP latency, response-locked LRP latency, and Nl EMG amplitude accounted for 40% of overall variability in individual extroversion scores. On the basis of the present results, the authors introduce a compensation hypothesis that accounts for the common failure of researchers to demonstrate extroversion-related differences in reaction time. The present results challenge J. Brebner and C. Cooper's (1985) model of extroversion in which stimulus analysis is not slower in introverts than in extroverts. However, the present findings support the assumption of faster motor processing in extroverts.

  4. The pace of vocabulary growth during preschool predicts cortical structure at school age.

    Science.gov (United States)

    Asaridou, Salomi S; Demir-Lira, Özlem Ece; Goldin-Meadow, Susan; Small, Steven L

    2017-04-01

    Children vary greatly in their vocabulary development during preschool years. Importantly, the pace of this early vocabulary growth predicts vocabulary size at school entrance. Despite its importance for later academic success, not much is known about the relation between individual differences in early vocabulary development and later brain structure and function. Here we examined the association between vocabulary growth in children, as estimated from longitudinal measurements from 14 to 58 months, and individual differences in brain structure measured in 3rd and 4th grade (8-10 years old). Our results show that the pace of vocabulary growth uniquely predicts cortical thickness in the left supramarginal gyrus. Probabilistic tractography revealed that this region is directly connected to the inferior frontal gyrus (pars opercularis) and the ventral premotor cortex, via what is most probably the superior longitudinal fasciculus III. Our findings demonstrate, for the first time, the relation between the pace of vocabulary learning in children and a specific change in the structure of the cerebral cortex, specifically, cortical thickness in the left supramarginal gyrus. They also highlight the fact that differences in the pace of vocabulary growth are associated with the dorsal language stream, which is thought to support speech perception and articulation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Nonfluent/Agrammatic PPA with In-Vivo Cortical Amyloidosis and Pick’s Disease Pathology

    Directory of Open Access Journals (Sweden)

    Francesca Caso

    2013-01-01

    Full Text Available The role of biomarkers in predicting pathological findings in the frontotemporal dementia (FTD clinical spectrum disorders is still being explored. We present comprehensive, prospective longitudinal data for a 66 year old, right-handed female who met current criteria for the nonfluent/agrammatic variant of primary progressive aphasia (nfvPPA. She first presented with a 3-year history of progressive speech and language impairment mainly characterized by severe apraxia of speech. Neuropsychological and general motor functions remained relatively spared throughout the clinical course. Voxel-based morphometry (VBM showed selective cortical atrophy of the left posterior inferior frontal gyrus (IFG and underlying insula that worsened over time, extending along the left premotor strip. Five years after her first evaluation, she developed mild memory impairment and underwent PET-FDG and PiB scans that showed left frontal hypometabolism and cortical amyloidosis. Three years later (11 years from first symptom, post-mortem histopathological evaluation revealed Pick's disease, with severe degeneration of left IFG, mid-insula, and precentral gyrus. Alzheimer’s disease (AD (CERAD frequent/Braak Stage V was also detected. This patient demonstrates that biomarkers indicating brain amyloidosis should not be considered conclusive evidence that AD pathology accounts for a typical FTD clinical/anatomical syndrome.

  6. A cortically-inspired model for inverse kinematics computation of a humanoid finger with mechanically coupled joints.

    Science.gov (United States)

    Gentili, Rodolphe J; Oh, Hyuk; Kregling, Alissa V; Reggia, James A

    2016-05-19

    The human hand's versatility allows for robust and flexible grasping. To obtain such efficiency, many robotic hands include human biomechanical features such as fingers having their two last joints mechanically coupled. Although such coupling enables human-like grasping, controlling the inverse kinematics of such mechanical systems is challenging. Here we propose a cortical model for fine motor control of a humanoid finger, having its two last joints coupled, that learns the inverse kinematics of the effector. This neural model functionally mimics the population vector coding as well as sensorimotor prediction processes of the brain's motor/premotor and parietal regions, respectively. After learning, this neural architecture could both overtly (actual execution) and covertly (mental execution or motor imagery) perform accurate, robust and flexible finger movements while reproducing the main human finger kinematic states. This work contributes to developing neuro-mimetic controllers for dexterous humanoid robotic/prosthetic upper-extremities, and has the potential to promote human-robot interactions.

  7. Dendritic bundles, minicolumns, columns, and cortical output units

    Directory of Open Access Journals (Sweden)

    Giorgio Innocenti

    2010-03-01

    Full Text Available The search for the fundamental building block of the cerebral cortex has highlighted three structures, perpendicular to the cortical surface: i columns of neurons with radially invariant response properties, e.g., receptive field position, sensory modality, stimulus orientation or direction, frequency tuning etc. ii minicolumns of radially aligned cell bodies and iii bundles, constituted by the apical dendrites of pyramidal neurons with cell bodies in different layers. The latter were described in detail, and sometimes quantitatively, in several species and areas. It was recently suggested that the dendritic bundles consist of apical dendrites belonging to neurons projecting their axons to specific targets. We review the concept above and suggest that another structural and computational unit of cerebral cortex is the cortical output unit (COU, i.e. an assembly of bundles of apical dendrites and their parent cell bodies including each of the outputs to distant cortical or subcortical structures, of a given cortical locus (area or part of an area. This somato-dendritic assembly receives inputs some of which are common to the whole assembly and determine its radially invariant response properties, others are specific to one or more dendritic bundles, and determine the specific response signature of neurons in the different cortical layers and projecting to different targets.

  8. Regional cortical gray matter thickness differences associated with type 2 diabetes and major depression

    Science.gov (United States)

    Ajilore, Olusola; Narr, Katherine; Rosenthal, Jonah; Pham, Daniel; Hamilton, Liberty; Watari, Kecia; Elderkin-Thompson, Virginia; Darwin, Christine; Toga, Arthur; Kumar, Anand

    2010-01-01

    Objective The purpose of this study was to examine the effect of type 2 diabetes with major depression on cortical gray matter using magnetic resonance imaging and cortical pattern matching techniques. We hypothesized that diabetic subjects and depressed diabetic subjects would demonstrate decreased cortical gray matter thickness in prefrontal areas as compared to healthy control subjects. Methods Patients with type 2 diabetes (n=26) and patients diabetes and major depression (n=26) were compared with healthy controls (n=20). Gray matter thickness across the entire cortex was measured using cortical pattern matching methods. Results All subjects with diabetes demonstrated decreased cortical gray matter thickness in the left anterior cingulate region. Additionally, depressed diabetic subjects showed significant cortical gray matter decreases in bilateral prefrontal areas compared with healthy controls. Correlations between clinical variables and cortical gray matter thickness revealed a significant negative relationship with cerebrovascular risk factors across all three groups, most consistently in the left dorsomedial prefrontal cortex. A significant positive relationship between performance on attention and executive function tasks and cortical gray matter thickness predominately in left hemisphere regions was also seen across all subjects. Conclusion Depression and diabetes are associated with significant cortical gray matter thinning in medial prefrontal areas. PMID:20832254

  9. Application of cortical electrode, image fusion and intraoperative MRI navigation in surgical resection of epileptic lesions in functional area%皮层电极监测、图像融合和术中磁共振精确镜下导航技术在切除功能区癫痫灶的应用

    Institute of Scientific and Technical Information of China (English)

    潘隆盛; 凌至培; 徐强; 孙国臣; 陈晓雷; 许百男

    2012-01-01

    Objective To study the application of cortical electrode, image fusion and intra- operative MRI navigation in surgical resection of epileptic lesions in the functional area. Methods Application of cortical electrode, image fusion and intra-operative MRI navigation in surgical resection of epileptic lesions in 25 patients with refractory epilepsy was retrospectively analyzed. Intracranial cortical electrodes were implanted into epileptic lesions of the patients according to their VEEG during the first operation. Their cortical electrical activity was monitored, cerebral motor area was located by cortical electrical stimulation, a figure of correlation between epileptic lesion and functional area was plotted after operation, images of CT, MRI, MEG or PET were fused, and the epilepsy lesions were precisely removed under microscopic MRI navigation. Results Cortical electrical stimulation was successful in 25 epilepsy patients during the first operation and the cortical motor area around the epileptic lesion was accurately located. The images of MRI, MEG or PET for the patients were fused. Of the 25 patients, 20 underwent total resection of epileptic lesion and 5 underwent partial resection of the lesion under microscopic MRI navigation due to the overlapped lesion and functional area. The residual cortex was eradicated by thermal burn. Transient opposite extremity dysfunction was observed in 1 patient after operation. No permanent neurological deficit occurred in all patients after operation. Conclusion Accurate location of intracranial cortical electrodes is of great importance for monitoring epileptic lesions. Fusion of MRI, MEG or PET images and microscopic MRI navigation during operation can provide technical support for the precise resection of epileptic lesions and protection of the functional area.%目的 探讨颅内皮层电极监测、图像融合和术中磁共振精确导航技术在切除功能区癫痫灶的应用价值.方法 回顾分析25 例应用皮

  10. Assessing cortical network properties using TMS-EEG.

    Science.gov (United States)

    Rogasch, Nigel C; Fitzgerald, Paul B

    2013-07-01

    The past decade has seen significant developments in the concurrent use of transcranial magnetic stimulation (TMS) and electroencephalography (EEG) to directly assess cortical network properties such as excitability and connectivity in humans. New hardware solutions, improved EEG amplifier technology, and advanced data processing techniques have allowed substantial reduction of the TMS-induced artifact, which had previously rendered concurrent TMS-EEG impossible. Various physiological artifacts resulting from TMS have also been identified, and methods are being developed to either minimize or remove these sources of artifact. With these developments, TMS-EEG has unlocked regions of the cortex to researchers that were previously inaccessible to TMS. By recording the TMS-evoked response directly from the cortex, TMS-EEG provides information on the excitability, effective connectivity, and oscillatory tuning of a given cortical area, removing the need to infer such measurements from indirect measures. In the following review, we investigate the different online and offline methods for reducing artifacts in TMS-EEG recordings and the physiological information contained within the TMS-evoked cortical response. We then address the use of TMS-EEG to assess different cortical mechanisms such as cortical inhibition and neural plasticity, before briefly reviewing studies that have utilized TMS-EEG to explore cortical network properties at rest and during different functional brain states.

  11. Somatostatin-expressing inhibitory interneurons in cortical circuits

    Directory of Open Access Journals (Sweden)

    Iryna Yavorska

    2016-09-01

    Full Text Available Cortical inhibitory neurons exhibit remarkable diversity in their morphology, connectivity, and synaptic properties. Here, we review the function of somatostatin-expressing (SOM inhibitory interneurons, focusing largely on sensory cortex. SOM neurons also comprise a number of subpopulations that can be distinguished by their morphology, input and output connectivity, laminar location, firing properties, and expression of molecular markers. Several of these classes of SOM neurons show unique dynamics and characteristics, such as facilitating synapses, specific axonal projections, intralaminar input, and top-down modulation, which suggest possible computational roles. SOM cells can be differentially modulated by behavioral state depending on their class, sensory system, and behavioral paradigm. The functional effects of such modulation have been studied with optogenetic manipulation of SOM cells, which produces effects on learning and memory, task performance, and the integration of cortical activity. Different classes of SOM cells participate in distinct disinhibitory circuits with different inhibitory partners and in different cortical layers. Through these disinhibitory circuits, SOM cells help encode the behavioral relevance of sensory stimuli by regulating the activity of cortical neurons based on subcortical and intracortical modulatory input. Associative learning leads to long-term changes in the strength of connectivity of SOM cells with other neurons, often influencing the strength of inhibitory input they receive. Thus despite their heterogeneity and variability across cortical areas, current evidence shows that SOM neurons perform unique neural computations, forming not only distinct molecular but also functional subclasses of cortical inhibitory interneurons.

  12. On how the motor cortices resolve an inter-hemispheric response conflict: an event-related EEG potential-guided TMS study of the flankers task

    DEFF Research Database (Denmark)

    Verleger, Rolf; Kuniecki, Michal; Möller, Friderike

    2009-01-01

    An important aspect of human motor control is the ability to resolve conflicting response tendencies. Here we used single-pulse transcranial magnetic stimulation (TMS) to track the time course of excitability changes in the primary motor hand areas (M1(HAND)) while the motor system resolved respo...... of the correct response in the other. This integrated implementation of response activation and cancellation at the level of the M1(HAND) presumably represents a downstream effect orchestrated by premotor brain regions....

  13. Hiperostosis cortical infantil

    Directory of Open Access Journals (Sweden)

    Salvador Javier Santos Medina

    2015-04-01

    Full Text Available La enfermedad de Caffey, o hiperostosis cortical infantil, es una rara enfermedad ósea autolimitada, que aparece de preferencia en lactantes con signos inespecíficos sistémicos; el más relevante es la reacción subperióstica e hiperostosis en varios huesos del cuerpo, con predilección en el 75-80 % de los casos por la mandíbula. Su pronóstico es bueno, la mayoría no deja secuelas. El propósito del presente trabajo es describir las características clínicas, presentes en un lactante de cinco meses de edad, atendido en el Hospital Pediátrico Provincial “Mártires de Las Tunas” con este diagnóstico, quien ingresó en el servicio de miscelánea B por una celulitis facial. Presentaba aumento de volumen en la región geniana izquierda, febrícola e inapetencia. Se impuso tratamiento con cefazolina y se egresó a los siete días. Acudió nuevamente con tumefacción blanda y difusa de ambas hemicaras, irritabilidad y fiebre. Se interconsultó con cirugía maxilofacial, se indicaron estudios sanguíneos y radiológicos. Se diagnosticó como enfermedad de Caffey, basado en la edad del niño, tumefacción facial sin signos inflamatorios agudos e hiperostosis en ambas corticales mandibulares a la radiografía AP mandíbula; unido a anemia ligera, leucocitosis y eritrosedimentación acelerada. El paciente se trató sintomáticamente y con antinflamatorios no esteroideos. Esta rara entidad se debe tener presente en casos de niños y lactantes con irritabilidad y fiebre inespecífica

  14. Late onset reversible cortical blindness following electrocution.

    Science.gov (United States)

    Chauhan, Bhumir; Philip, Vivek J; Shankar, Udaya C

    2015-12-01

    An elderly gentleman presented with acute onset of bilateral visual blurring and generalized headache after 1 week post electrocution injury. Clinically, the symptoms were attributed to cortical lesion. Magnetic resonance imaging (MRI) of brain revealed bilaterally symmetrical diffusion restriction in parietal and occipital areas. Treatment with intravenous steroids resulted in remarkable improvement in symptoms. Neurological injury secondary to electrocution is a well described entity having a variety of clinical presentation. We put forward our experience with this unique case presenting as post electrocution delayed onset of visual symptoms. Discussion and review of literature related to this clinical entity will also be presented.

  15. Object recognition by artificial cortical maps.

    Science.gov (United States)

    Plebe, Alessio; Domenella, Rosaria Grazia

    2007-09-01

    Object recognition is one of the most important functions of the human visual system, yet one of the least understood, this despite the fact that vision is certainly the most studied function of the brain. We understand relatively well how several processes in the cortical visual areas that support recognition capabilities take place, such as orientation discrimination and color constancy. This paper proposes a model of the development of object recognition capability, based on two main theoretical principles. The first is that recognition does not imply any sort of geometrical reconstruction, it is instead fully driven by the two dimensional view captured by the retina. The second assumption is that all the processing functions involved in recognition are not genetically determined or hardwired in neural circuits, but are the result of interactions between epigenetic influences and basic neural plasticity mechanisms. The model is organized in modules roughly related to the main visual biological areas, and is implemented mainly using the LISSOM architecture, a recent neural self-organizing map model that simulates the effects of intercortical lateral connections. This paper shows how recognition capabilities, similar to those found in brain ventral visual areas, can develop spontaneously by exposure to natural images in an artificial cortical model.

  16. Cortical changes in cerebral small vessel diseases: a 3D MRI study of cortical morphology in CADASIL

    Energy Technology Data Exchange (ETDEWEB)

    Jouvent, E.; Bousser, M.G.; Chabriat, H. [CHU Lariboisiere, AP HP, INSERM, UMR 740, Dept Neurol, Lariboisiere (France); Jouvent, E.; Bousser, M.G.; Chabriat, H. [Univ Paris 07, F-75221 Paris 05 (France); Porcher, R. [Hop St Louis, AP-HP, Dept Biostat, St Louis (France); Viswanathan, A. [Massachusetts Gen Hosp, Dept Neurol, Boston, MA 02114 (United States); Viswanathan, A. [Massachusetts Gen Hosp, Clin Trials Unit, Boston, MA 02114 (United States); Viswanathan, A. [Harvard Univ, Sch Med, Boston, MA (United States); O' Sullivan, M.; Dichgans, M. [Univ Munich, Klinikum Grosshadern, Dept Neurol, D-81377 Munich (Germany); Guichard, J.P. [CHU Lariboisiere, AP-HP, Dept Neuroradiol, Lariboisiere (France)

    2008-07-01

    Brain atrophy represents a key marker of disease progression in cerebrovascular disorders. The 3D changes of cortex morphology occurring during the course of small vessel diseases of the brain (SVDB) remain poorly understood. The objective of this study was to assess the changes affecting depth and surface area of cortical sulci and their clinical and radiological correlates in a cohort of patients with cerebral autosomal dominant arteriolopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a genetic SVDB. Data were obtained from a series of 69 CADASIL patients. Validated methods were used to determine depth and surface area of four cortical sulci. The ratio of brain to intracranial cavity volumes (brain parenchymal fraction-BPF), volume of lacunar lesions (LL) and of white matter hyper-intensities, number of cerebral micro-haemorrhages, and mean apparent diffusion coefficient were also measured. Association between depth and surface area of the cortical sulci and BPF, clinical status and subcortical MRI lesions were tested. Depth and surface area of cortical sulci obtained in 54 patients were strongly correlated with both cognitive score and disability scales. Depth was related to the extent of subcortical lesions, surface area was related only to age. In additional analyses, the depth of the cingular sulcus was independently associated with the volume of LL (P 0.001), and that of the superior frontal sulcus with the mean apparent diffusion coefficient (P 0.003). In CADASIL, important morphological changes of cortical sulci occur in association with clinical worsening,extension of subcortical tissue damage and progression of global cerebral atrophy. These results suggest that the examination of cortical morphology may be of high clinical relevance in SVDB. (authors)

  17. Cortical regions involved in the generation of musical structures during improvisation in pianists.

    Science.gov (United States)

    Bengtsson, Sara L; Csíkszentmihályi, Mihály; Ullén, Fredrik

    2007-05-01

    Studies on simple pseudorandom motor and cognitive tasks have shown that the dorsolateral prefrontal cortex and rostral premotor areas are involved in free response selection. We used functional magnetic resonance imaging to investigate whether these brain regions are also involved in free generation of responses in a more complex creative behavior: musical improvisation. Eleven professional pianists participated in the study. In one condition, Improvise, the pianist improvised on the basis of a visually displayed melody. In the control condition, Reproduce, the participant reproduced his previous improvisation from memory. Participants were able to reproduce their improvisations with a high level of accuracy, and the contrast Improvise versus Reproduce was thus essentially matched in terms of motor output and sensory feedback. However, the Improvise condition required storage in memory of the improvisation. We therefore also included a condition FreeImp, where the pianist improvised but was instructed not to memorize his performance. To locate brain regions involved in musical creation, we investigated the activations in the Improvise-Reproduce contrast that were also present in FreeImp contrasted with a baseline rest condition. Activated brain regions included the right dorsolateral prefrontal cortex, the presupplementary motor area, the rostral portion of the dorsal premotor cortex, and the left posterior part of the superior temporal gyrus. We suggest that these regions are part of a network involved in musical creation, and discuss their possible functional roles.

  18. Visual change detection recruits auditory cortices in early deafness.

    Science.gov (United States)

    Bottari, Davide; Heimler, Benedetta; Caclin, Anne; Dalmolin, Anna; Giard, Marie-Hélène; Pavani, Francesco

    2014-07-01

    Although cross-modal recruitment of early sensory areas in deafness and blindness is well established, the constraints and limits of these plastic changes remain to be understood. In the case of human deafness, for instance, it is known that visual, tactile or visuo-tactile stimuli can elicit a response within the auditory cortices. Nonetheless, both the timing of these evoked responses and the functional contribution of cross-modally recruited areas remain to be ascertained. In the present study, we examined to what extent auditory cortices of deaf humans participate in high-order visual processes, such as visual change detection. By measuring visual ERPs, in particular the visual MisMatch Negativity (vMMN), and performing source localization, we show that individuals with early deafness (N=12) recruit the auditory cortices when a change in motion direction during shape deformation occurs in a continuous visual motion stream. Remarkably this "auditory" response for visual events emerged with the same timing as the visual MMN in hearing controls (N=12), between 150 and 300 ms after the visual change. Furthermore, the recruitment of auditory cortices for visual change detection in early deaf was paired with a reduction of response within the visual system, indicating a shift from visual to auditory cortices of part of the computational process. The present study suggests that the deafened auditory cortices participate at extracting and storing the visual information and at comparing on-line the upcoming visual events, thus indicating that cross-modally recruited auditory cortices can reach this level of computation.

  19. Muscle synergy patterns as physiological markers of motor cortical damage.

    Science.gov (United States)

    Cheung, Vincent C K; Turolla, Andrea; Agostini, Michela; Silvoni, Stefano; Bennis, Caoimhe; Kasi, Patrick; Paganoni, Sabrina; Bonato, Paolo; Bizzi, Emilio

    2012-09-04

    The experimental findings herein reported are aimed at gaining a perspective on the complex neural events that follow lesions of the motor cortical areas. Cortical damage, whether by trauma or stroke, interferes with the flow of descending signals to the modular interneuronal structures of the spinal cord. These spinal modules subserve normal motor behaviors by activating groups of muscles as individual units (muscle synergies). Damage to the motor cortical areas disrupts the orchestration of the modules, resulting in abnormal movements. To gain insights into this complex process, we recorded myoelectric signals from multiple upper-limb muscles in subjects with cortical lesions. We used a factorization algorithm to identify the muscle synergies. Our factorization analysis revealed, in a quantitative way, three distinct patterns of muscle coordination-including preservation, merging, and fractionation of muscle synergies-that reflect the multiple neural responses that occur after cortical damage. These patterns varied as a function of both the severity of functional impairment and the temporal distance from stroke onset. We think these muscle-synergy patterns can be used as physiological markers of the status of any patient with stroke or trauma, thereby guiding the development of different rehabilitation approaches, as well as future physiological experiments for a further understanding of postinjury mechanisms of motor control and recovery.

  20. Buccal cortical bone thickness on CBCT for mini-implant

    Energy Technology Data Exchange (ETDEWEB)

    Goo, Jong Gook; Lim, Sung Hoon; Lee, Byoung Jin; Kim, Jae Duk [School of Dentistry, Chosun University, Gwangju (Korea, Republic of)

    2010-12-15

    Cortical bone thickness is one of the important factor in mini-implant stability. This study was performed to investigate the buccal cortical bone thickness at every interdental area as an aid in planning mini-implant placement. Two-dimensional slices at every interdental area were selected from the cone-beam computed tomography scans of 20 patients in third decade. Buccal cortical bone thickness was measured at 2, 4, and 6 mm levels from the alveolar crest in the interdental bones of posterior regions of both jaws using the plot profile function of Ez3D2009TM (Vatech, Yongin, Korea). The results were analyzed using by Mann-Whitney test. Buccal cortical bone was thicker in the mandible than in the maxilla. The thickness increased with further distance from the alveolar crest in the maxilla and with coming from the posterior to anterior region in the mandible (p?0.01). The maximum CT value showed an increasing tendency with further distance from the alveolar crest and with coming from posterior to anterior region in both jaws. Interdental buccal cortical bone thickness varied in both jaws, however our study showed a distinct tendency. We expect that these results could be helpful for the selection and preparation of mini-implant sites.

  1. Cortical thinning in subcortical vascular dementia with negative 11C-PiB PET.

    Science.gov (United States)

    Kim, Chi Hun; Seo, Sang Won; Kim, Geon Ha; Shin, Ji Soo; Cho, Hanna; Noh, Young; Kim, Suk-Hui; Kim, Min Ji; Jeon, Seun; Yoon, Uicheul; Lee, Jong-Min; Oh, Seung Jun; Kim, Jae Seung; Kim, Sung Tae; Lee, Jae-Hong; Na, Duk L

    2012-01-01

    To determine the existence of cortical thinning in subcortical vascular dementia (SVaD) with a negative 11C-Pittsburgh compound B (PiB) positron emission tomography scan and to compare the topography of cortical thinning between PiB-negative SVaD and Alzheimer's disease (AD), we enrolled 24 patients with PiB(-) SVaD, 81 clinically probable AD individuals, and 72 normal cognitive controls. Compared with controls, cortical thinning in PiB(-) SVaD was most profound in the perisylvian area, medial prefrontal area, and posterior cingulate gyri, while the precuneus and medial temporal lobes were relatively spared. When the cortical thickness of AD and PiB(-) SVaD were directly compared, PiB(-) SVaD demonstrated significant cortical thinning in the bilateral inferior frontal, superior temporal gyri, and right medial frontal and orbitofrontal lobes, while AD showed significant cortical thinning in the right medial temporal region. SVaD without amyloid burden may lead to substantial cortical atrophy. Moreover, characteristic topography of cortical thinning in PiB(-) SVaD suggests different mechanisms of cortical thinning in PiB(-) SVaD and AD.

  2. Continuous theta burst stimulation over the left pre-motor cortex affects sensorimotor timing accuracy and supraliminal error correction.

    Science.gov (United States)

    Bijsterbosch, Janine D; Lee, Kwang-Hyuk; Dyson-Sutton, William; Barker, Anthony T; Woodruff, Peter W R

    2011-09-02

    Adjustments to movement in response to changes in our surroundings are common in everyday behavior. Previous research has suggested that the left pre-motor cortex (PMC) is specialized for the temporal control of movement and may play a role in temporal error correction. The aim of this study was to determine the role of the left PMC in sensorimotor timing and error correction using theta burst transcranial magnetic stimulation (TBS). In Experiment 1, subjects performed a sensorimotor synchronization task (SMS) with the left and the right hand before and after either continuous or intermittent TBS (cTBS or iTBS). Timing accuracy was assessed during synchronized finger tapping with a regular auditory pacing stimulus. Responses following perceivable local timing shifts in the pacing stimulus (phase shifts) were used to measure error correction. Suppression of the left PMC using cTBS decreased timing accuracy because subjects tapped further away from the pacing tones and tapping variability increased. In addition, error correction responses returned to baseline tap-tone asynchrony levels faster following negative shifts and no overcorrection occurred following positive shifts after cTBS. However, facilitation of the left PMC using iTBS did not affect timing accuracy or error correction performance. Experiment 2 revealed that error correction performance may change with practice, independent of TBS. These findings provide evidence for a role of the left PMC in both sensorimotor timing and error correction in both hands. We propose that the left PMC may be involved in voluntarily controlled phase correction responses to perceivable timing shifts.

  3. Leading role of thalamic over cortical neurons during postinhibitory rebound excitation

    Science.gov (United States)

    Grenier, F.; Timofeev, I.; Steriade, M.

    1998-01-01

    The postinhibitory rebound excitation is an intrinsic property of thalamic and cortical neurons that is implicated in a variety of normal and abnormal operations of neuronal networks, such as slow or fast brain rhythms during different states of vigilance as well as seizures. We used dual simultaneous intracellular recordings of thalamocortical neurons from the ventrolateral nucleus and neurons from the motor cortex, together with thalamic and cortical field potentials, to investigate the temporal relations between thalamic and cortical events during the rebound excitation that follows prolonged periods of stimulus-induced inhibition. Invariably, the rebound spike-bursts in thalamocortical cells occurred before the rebound depolarization in cortical neurons and preceded the peak of the depth-negative, rebound field potential in cortical areas. Also, the inhibitory-rebound sequences were more pronounced and prolonged in cortical neurons when elicited by thalamic stimuli, compared with cortical stimuli. The role of thalamocortical loops in the rebound excitation of cortical neurons was shown further by the absence of rebound activity in isolated cortical slabs. However, whereas thalamocortical neurons remained hyperpolarized after rebound excitation, because of the prolonged spike-bursts in inhibitory thalamic reticular neurons, the rebound depolarization in cortical neurons was prolonged, suggesting the role of intracortical excitatory circuits in this sustained activity. The role of intrathalamic events in triggering rebound cortical activity should be taken into consideration when analyzing information processes at the cortical level; at each step, corticothalamic volleys can set into action thalamic inhibitory neurons, leading to rebound spike-bursts that are transferred back to the cortex, thus modifying cortical activities. PMID:9811903

  4. Cortical Correlates of Fitts’ Law

    Directory of Open Access Journals (Sweden)

    Peter eIfft

    2011-12-01

    Full Text Available Fitts' law describes the fundamental trade-off between movement accuracy and speed: It states that the duration of reaching movements is a function of target size and distance. While Fitts' law has been extensively studied in ergonomics and has guided the design of human-computer interfaces, there have been few studies on its neuronal correlates. To elucidate sensorimotor cortical activity underlying Fitts’ law, we implanted two monkeys with multielectrode arrays in the primary motor (M1 and primary somatosensory (S1 cortices. The monkeys performed reaches with a joystick-controlled cursor towards targets of different size. The reaction time, movement time and movement velocity changed with target size, and M1 and S1 activity reflected these changes. Moreover, modifications of cortical activity could not be explained by changes of movement parameters alone, but required target size as an additional parameter. Neuronal representation of target size was especially prominent during the early reaction time period where it influenced the slope of the firing rate rise preceding movement initiation. During the movement period, cortical activity was mostly correlated with movement velocity. Neural decoders were applied to simultaneously decode target size and motor parameters from cortical modulations. We suggest using such classifiers to improve neuroprosthetic control.

  5. The mirror neuron system and the strange case of Broca's area.

    Science.gov (United States)

    Cerri, Gabriella; Cabinio, Monia; Blasi, Valeria; Borroni, Paola; Iadanza, Antonella; Fava, Enrica; Fornia, Luca; Ferpozzi, Valentina; Riva, Marco; Casarotti, Alessandra; Martinelli Boneschi, Filippo; Falini, Andrea; Bello, Lorenzo

    2015-03-01

    Mirror neurons, originally described in the monkey premotor area F5, are embedded in a frontoparietal network for action execution and observation. A similar Mirror Neuron System (MNS) exists in humans, including precentral gyrus, inferior parietal lobule, and superior temporal sulcus. Controversial is the inclusion of Broca's area, as homologous to F5, a relevant issue in light of the mirror hypothesis of language evolution, which postulates a key role of Broca's area in action/speech perception/production. We assess "mirror" properties of this area by combining neuroimaging and intraoperative neurophysiological techniques. Our results show that Broca's area is minimally involved in action observation and has no motor output on hand or phonoarticulatory muscles, challenging its inclusion in the MNS. The presence of these functions in premotor BA6 makes this area the likely homologue of F5 suggesting that the MNS may be involved in the representation of articulatory rather than semantic components of speech. © 2014 Wiley Periodicals, Inc.

  6. Cortical myoclonus in Huntington's disease.

    Science.gov (United States)

    Thompson, P D; Bhatia, K P; Brown, P; Davis, M B; Pires, M; Quinn, N P; Luthert, P; Honovar, M; O'Brien, M D; Marsden, C D

    1994-11-01

    We describe three patients with Huntington's disease, from two families, in whom myoclonus was the predominant clinical feature. The diagnosis was confirmed at autopsy in two cases and by DNA analysis in all three. These patients all presented before the age of 30 years and were the offspring of affected fathers. Neurophysiological studies documented generalised and multifocal action myoclonus of cortical origin that was strikingly stimulus sensitive, without enlargement of the cortical somatosensory evoked potential. The myoclonus improved with piracetam therapy in one patient and a combination of sodium valproate and clonazepam in the other two. Cortical reflex myoclonus is a rare but disabling component of the complex movement disorder of Huntington's disease, which may lead to substantial diagnostic difficulties.

  7. Reduced cortical thickness associated with visceral fat and BMI

    Directory of Open Access Journals (Sweden)

    Ralf Veit

    2014-01-01

    Full Text Available Structural brain imaging studies have shown that obesity is associated with widespread reductions in gray matter (GM volume. Although the body mass index (BMI is an easily accessible anthropometric measure, substantial health problems are more related to specific body fat compartments, like visceral adipose tissue (VAT. We investigated cortical thickness measures in a group of 72 healthy subjects (BMI range 20–35 kg/m2, age range 19–50 years. Multiple regression analyses were performed using VAT and BMI as predictors and age, gender, total surface area and education as confounds. BMI and VAT were independently associated with reductions in cortical thickness in clusters comprising the left lateral occipital area, the left inferior temporal cortex, and the left precentral and inferior parietal area, while the right insula, the left fusiform gyrus and the right inferior temporal area showed a negative correlation with VAT only. In addition, we could show significant reductions in cortical thickness with increasing VAT adjusted for BMI in the left temporal cortex. We were able to detect widespread cortical thinning in a young to middle-aged population related to BMI and VAT; these findings show close resemblance to studies focusing on GM volume differences in diabetic patients. This may point to the influence of VAT related adverse effects, like low-grade inflammation, as a potentially harmful factor on brain integrity already in individuals at risk of developing diabetes, metabolic syndromes and arteriosclerosis.

  8. Quantitative Architectural Analysis: A New Approach to Cortical Mapping

    Science.gov (United States)

    Schleicher, Axel; Morosan, Patricia; Amunts, Katrin; Zilles, Karl

    2009-01-01

    Results from functional imaging studies are often still interpreted using the classical architectonic brain maps of Brodmann and his successors. One obvious weakness in traditional, architectural mapping is the subjective nature of localizing borders between cortical areas by means of a purely visual, microscopical examination of histological…

  9. Quantitative Architectural Analysis: A New Approach to Cortical Mapping

    Science.gov (United States)

    Schleicher, Axel; Morosan, Patricia; Amunts, Katrin; Zilles, Karl

    2009-01-01

    Results from functional imaging studies are often still interpreted using the classical architectonic brain maps of Brodmann and his successors. One obvious weakness in traditional, architectural mapping is the subjective nature of localizing borders between cortical areas by means of a purely visual, microscopical examination of histological…

  10. Grid cells and cortical representation.

    Science.gov (United States)

    Moser, Edvard I; Roudi, Yasser; Witter, Menno P; Kentros, Clifford; Bonhoeffer, Tobias; Moser, May-Britt

    2014-07-01

    One of the grand challenges in neuroscience is to comprehend neural computation in the association cortices, the parts of the cortex that have shown the largest expansion and differentiation during mammalian evolution and that are thought to contribute profoundly to the emergence of advanced cognition in humans. In this Review, we use grid cells in the medial entorhinal cortex as a gateway to understand network computation at a stage of cortical processing in which firing patterns are shaped not primarily by incoming sensory signals but to a large extent by the intrinsic properties of the local circuit.

  11. Paroxysmal kinesigenic dyskinesia : Cortical or non-cortical origin

    NARCIS (Netherlands)

    van Strien, Teun W.; van Rootselaar, Anne-Fleur; Hilgevoord, Anthony A. J.; Linssen, Wim H. J. P.; Groffen, Alexander J. A.; Tijssen, Marina A. J.

    2012-01-01

    Paroxysmal kinesigenic dyskinesia (PKD) is characterized by involuntary dystonia and/or chorea triggered by a sudden movement. Cases are usually familial with an autosomal dominant inheritance. Hypotheses regarding the pathogenesis of PKD focus on the controversy whether PKD has a cortical or non-co

  12. Associations between children's socioeconomic status and prefrontal cortical thickness.

    Science.gov (United States)

    Lawson, Gwendolyn M; Duda, Jeffrey T; Avants, Brian B; Wu, Jue; Farah, Martha J

    2013-09-01

    Childhood socioeconomic status (SES) predicts executive function performance and measures of prefrontal cortical function, but little is known about its anatomical correlates. Structural MRI and demographic data from a sample of 283 healthy children from the NIH MRI Study of Normal Brain Development were used to investigate the relationship between SES and prefrontal cortical thickness. Specifically, we assessed the association between two principal measures of childhood SES, family income and parental education, and gray matter thickness in specific subregions of prefrontal cortex and on the asymmetry of these areas. After correcting for multiple comparisons and controlling for potentially confounding variables, parental education significantly predicted cortical thickness in the right anterior cingulate gyrus and left superior frontal gyrus. These results suggest that brain structure in frontal regions may provide a meaningful link between SES and cognitive function among healthy, typically developing children. © 2013 John Wiley & Sons Ltd.

  13. Shortened cortical silent period in adductor spasmodic dysphonia: evidence for widespread cortical excitability.

    Science.gov (United States)

    Samargia, Sharyl; Schmidt, Rebekah; Kimberley, Teresa Jacobson

    2014-02-07

    The purpose of this study was to compare cortical inhibition in the hand region of the primary motor cortex between subjects with focal hand dystonia (FHD), adductor spasmodic dysphonia (AdSD), and healthy controls. Data from 28 subjects were analyzed (FHD n=11, 53.25 ± 8.74 y; AdSD: n=8, 56.38 ± 7.5 y; and healthy controls: n=941.67 ± 10.85 y). All subjects received single pulse TMS to the left motor cortex to measure cortical silent period (CSP) in the right first dorsal interosseus (FDI) muscle. Duration of the CSP was measured and compared across groups. A one-way ANCOVA with age as a covariate revealed a significant group effect (p<0.001). Post hoc analysis revealed significantly longer CSP duration in the healthy group vs. AdSD group (p<0.001) and FHD group (p<0.001). These results suggest impaired intracortical inhibition is a neurophysiologic characteristic of FHD and AdSD. In addition, the shortened CSP in AdSD provides evidence to support a widespread decrease in cortical inhibition in areas of the motor cortex that represent an asymptomatic region of the body. These findings may inform future investigations of differential diagnosis as well as alternative treatments for focal dystonias.

  14. Tactile thermal oral stimulation increases the cortical representation of swallowing

    Directory of Open Access Journals (Sweden)

    Suntrup Sonja

    2009-06-01

    Full Text Available Abstract Background Dysphagia is a leading complication in stroke patients causing aspiration pneumonia, malnutrition and increased mortality. Current strategies of swallowing therapy involve on the one hand modification of eating behaviour or swallowing technique and on the other hand facilitation of swallowing with the use of pharyngeal sensory stimulation. Thermal tactile oral stimulation (TTOS is an established method to treat patients with neurogenic dysphagia especially if caused by sensory deficits. Little is known about the possible mechanisms by which this interventional therapy may work. We employed whole-head MEG to study changes in cortical activation during self-paced volitional swallowing in fifteen healthy subjects with and without TTOS. Data were analyzed by means of synthetic aperture magnetometry (SAM and the group analysis of individual SAM data was performed using a permutation test. Results Compared to the normal swallowing task a significantly increased bilateral cortical activation was seen after oropharyngeal stimulation. Analysis of the chronological changes during swallowing suggests facilitation of both the oral and the pharyngeal phase of deglutition. Conclusion In the present study functional cortical changes elicited by oral sensory stimulation could be demonstrated. We suggest that these results reflect short-term cortical plasticity of sensory swallowing areas. These findings facilitate our understanding of the role of cortical reorganization in dysphagia treatment and recovery.

  15. Decoding of covert vowel articulation using electroencephalography cortical currents

    Directory of Open Access Journals (Sweden)

    Natsue eYoshimura

    2016-05-01

    Full Text Available With the goal of providing assistive technology for the communication impaired, we proposed electroencephalography (EEG cortical currents as a new approach for EEG-based brain-computer interface spellers. EEG cortical currents were estimated with a variational Bayesian method that uses functional magnetic resonance imaging (fMRI data as a hierarchical prior. EEG and fMRI data were recorded from ten healthy participants during covert articulation of Japanese vowels /a/ and /i/, as well as during a no-imagery control task. Applying a sparse logistic regression (SLR method to classify the three tasks, mean classification accuracy using EEG cortical currents was significantly higher than that using EEG sensor signals and was also comparable to accuracies in previous studies using electrocorticography. SLR weight analysis revealed vertices of EEG cortical currents that were highly contributive to classification for each participant, and the vertices showed discriminative time series signals according to the three tasks. Furthermore, functional connectivity analysis focusing on the highly contributive vertices revealed positive and negative correlations among areas related to speech processing. As the same findings were not observed using EEG sensor signals, our results demonstrate the potential utility of EEG cortical currents not only for engineering purposes such as brain-computer interfaces but also for neuroscientific purposes such as the identification of neural signaling related to language processing.

  16. Cortical plasticity as a new endpoint measurement for chronic pain

    Directory of Open Access Journals (Sweden)

    Zhuo Min

    2011-07-01

    Full Text Available Abstract Animal models of chronic pain are widely used to investigate basic mechanisms of chronic pain and to evaluate potential novel drugs for treating chronic pain. Among the different criteria used to measure chronic pain, behavioral responses are commonly used as the end point measurements. However, not all chronic pain conditions can be easily measured by behavioral responses such as the headache, phantom pain and pain related to spinal cord injury. Here I propose that cortical indexes, that indicate neuronal plastic changes in pain-related cortical areas, can be used as endpoint measurements for chronic pain. Such cortical indexes are not only useful for those chronic pain conditions where a suitable animal model is lacking, but also serve as additional screening methods for potential drugs to treat chronic pain in humans. These cortical indexes are activity-dependent immediate early genes, electrophysiological identified plastic changes and biochemical assays of signaling proteins. It can be used to evaluate novel analgesic compounds that may act at peripheral or spinal sites. I hope that these new cortical endpoint measurements will facilitate our search for new, and more effective, pain medicines, and help to reduce false lead drug targets.

  17. Decoding of Covert Vowel Articulation Using Electroencephalography Cortical Currents

    Science.gov (United States)

    Yoshimura, Natsue; Nishimoto, Atsushi; Belkacem, Abdelkader Nasreddine; Shin, Duk; Kambara, Hiroyuki; Hanakawa, Takashi; Koike, Yasuharu

    2016-01-01

    With the goal of providing assistive technology for the communication impaired, we proposed electroencephalography (EEG) cortical currents as a new approach for EEG-based brain-computer interface spellers. EEG cortical currents were estimated with a variational Bayesian method that uses functional magnetic resonance imaging (fMRI) data as a hierarchical prior. EEG and fMRI data were recorded from ten healthy participants during covert articulation of Japanese vowels /a/ and /i/, as well as during a no-imagery control task. Applying a sparse logistic regression (SLR) method to classify the three tasks, mean classification accuracy using EEG cortical currents was significantly higher than that using EEG sensor signals and was also comparable to accuracies in previous studies using electrocorticography. SLR weight analysis revealed vertices of EEG cortical currents that were highly contributive to classification for each participant, and the vertices showed discriminative time series signals according to the three tasks. Furthermore, functional connectivity analysis focusing on the highly contributive vertices revealed positive and negative correlations among areas related to speech processing. As the same findings were not observed using EEG sensor signals, our results demonstrate the potential utility of EEG cortical currents not only for engineering purposes such as brain-computer interfaces but also for neuroscientific purposes such as the identification of neural signaling related to language processing. PMID:27199638

  18. Face activated neurodynamic cortical networks.

    Science.gov (United States)

    Susac, Ana; Ilmoniemi, Risto J; Ranken, Doug; Supek, Selma

    2011-05-01

    Previous neuroimaging studies have shown that complex visual stimuli, such as faces, activate multiple brain regions, yet little is known on the dynamics and complexity of the activated cortical networks during the entire measurable evoked response. In this study, we used simulated and face-evoked empirical MEG data from an oddball study to investigate the feasibility of accurate, efficient, and reliable spatio-temporal tracking of cortical pathways over prolonged time intervals. We applied a data-driven, semiautomated approach to spatio-temporal source localization with no prior assumptions on active cortical regions to explore non-invasively face-processing dynamics and their modulation by task. Simulations demonstrated that the use of multi-start downhill simplex and data-driven selections of time intervals submitted to the Calibrated Start Spatio-Temporal (CSST) algorithm resulted in improved accuracy of the source localization and the estimation of the onset of their activity. Locations and dynamics of the identified sources indicated a distributed cortical network involved in face processing whose complexity was task dependent. This MEG study provided the first non-invasive demonstration, agreeing with intracranial recordings, of an early onset of the activity in the fusiform face gyrus (FFG), and that frontal activation preceded parietal for responses elicited by target faces.

  19. The cortical motor system of the marmoset monkey (Callithrix jacchus).

    Science.gov (United States)

    Bakola, Sophia; Burman, Kathleen J; Rosa, Marcello G P

    2015-04-01

    Precise descriptions of the anatomical pathways that link different areas of the cerebral cortex are essential to the understanding of the sensorimotor and association processes that underlie human actions, and their impairment in pathological situations. Many years of research in macaque monkeys have critically shaped how we currently think about cortical motor function in humans. However, it is important to obtain additional understanding about the homologies between cortical areas in human and various non-human primates, and in particular how evolutionary changes in connectivity within specific neural circuits impact on the capacity for different behaviors. Current research has converged on the New World marmoset monkey as an important animal model for cortical function and dysfunction, emphasizing advantages unique to this species. However, the motor repertoire of the marmoset differs from that of the macaque in many ways, including the capacity for skilled use of the hands. Here, we review current knowledge about the cortical frontal areas in marmosets, which are key to the generation and control of motor behaviors, with focus on comparative analyses. We note significant parallels with the macaque monkey, as well as a few potentially important differences, which suggest future directions for work involving architectonic and functional analyses.

  20. [Functional magnetic resonance imaging for cortical mapping in epilepsy].

    Science.gov (United States)

    Lajos, Rudolf Kozák; Tóth, Vivien; Barsi, Péter; Rudas, Gábor

    2011-09-30

    It is not only the total curative resection of pathological tissue or the minimization of symptoms to be considered in epilepsy surgery or other neurosurgical procedures, it is equally desirable to maintain the best possible quality of life. Cortical mapping methods can help achieve this goal by delineating eloquent areas, i.e. brain regions that are vital for providing an acceptable quality of life, albeit not prone to compensatory reorganization. These areas include among others the Broca and Wernicke regions for speech, the primary motor, sensory and visual cortices. Functional MRI gained importance in the last decade as a non-invasive clinical cortical mapping technique. This method is capable of localizing cortical areas selectively activated by a given task condition. Thus, selecting appropriate tasks can help mapping eloquent brain regions. Using functional MRI provides information that is complementary to other mapping methods. Moreover, it can replace invasive methods such as the Wada test. Here, we explain the background of functional MRI, compare it to other clinical mapping methods, explain the intricacies of paradigm selection, and show the limitations of the technique while also pointing out alternative uses.

  1. Associations between cortical thickness and general intelligence in children, adolescents and young adults

    NARCIS (Netherlands)

    K. Menary (Kyle); P.F. Collins (Paul); J.N. Porter (James); R.L. Muetzel (Ryan); E.A. Olson (Elizabeth); V. Kumar (Vipin); D. Steinbach; K.O. Lim (Kelvin); M. Luciana (Monica)

    2013-01-01

    textabstractNeuroimaging research indicates that human intellectual ability is related to brain structure including the thickness of the cerebral cortex. Most studies indicate that general intelligence is positively associated with cortical thickness in areas of association cortex distributed

  2. Decreased Cerebellar Fiber Density in Cortical Myoclonic Tremor but Not in Essential Tremor

    NARCIS (Netherlands)

    Buijink, Arthur W. G.; Caan, Matthan W. A.; Tijssen, Marina A. J.; Hoogduin, Johannes M.; Maurits, Natasha M.; van Rootselaar, Anne-Fleur

    Pathophysiology of tremor generation remains uncertain in 'familial cortical myoclonic tremor with epilepsy' (FCMTE) and essential tremor (ET). In both disorders, imaging and pathological studies suggest involvement of the cerebellum and its projection areas. MR diffusion tensor imaging allows

  3. Associations between cortical thickness and general intelligence in children, adolescents and young adults

    NARCIS (Netherlands)

    K. Menary (Kyle); P.F. Collins (Paul); J.N. Porter (James); R.L. Muetzel (Ryan); E.A. Olson (Elizabeth); V. Kumar (Vipin); D. Steinbach; K.O. Lim (Kelvin); M. Luciana (Monica)

    2013-01-01

    textabstractNeuroimaging research indicates that human intellectual ability is related to brain structure including the thickness of the cerebral cortex. Most studies indicate that general intelligence is positively associated with cortical thickness in areas of association cortex distributed throug

  4. Decreased Cerebellar Fiber Density in Cortical Myoclonic Tremor but Not in Essential Tremor

    NARCIS (Netherlands)

    Buijink, Arthur W. G.; Caan, Matthan W. A.; Tijssen, Marina A. J.; Hoogduin, Johannes M.; Maurits, Natasha M.; van Rootselaar, Anne-Fleur

    2013-01-01

    Pathophysiology of tremor generation remains uncertain in 'familial cortical myoclonic tremor with epilepsy' (FCMTE) and essential tremor (ET). In both disorders, imaging and pathological studies suggest involvement of the cerebellum and its projection areas. MR diffusion tensor imaging allows estim

  5. Crowding: a cortical constraint on object recognition.

    Science.gov (United States)

    Pelli, Denis G

    2008-08-01

    The external world is mapped retinotopically onto the primary visual cortex (V1). We show here that objects in the world, unless they are very dissimilar, can be recognized only if they are sufficiently separated in visual cortex: specifically, in V1, at least 6mm apart in the radial direction (increasing eccentricity) or 1mm apart in the circumferential direction (equal eccentricity). Objects closer together than this critical spacing are perceived as an unidentifiable jumble. This is called 'crowding'. It severely limits visual processing, including speed of reading and searching. The conclusion about visual cortex rests on three findings. First, psychophysically, the necessary 'critical' spacing, in the visual field, is proportional to (roughly half) the eccentricity of the objects. Second, the critical spacing is independent of the size and kind of object. Third, anatomically, the representation of the visual field on the cortical surface is such that the position in V1 (and several other areas) is the logarithm of eccentricity in the visual field. Furthermore, we show that much of this can be accounted for by supposing that each 'combining field', defined by the critical spacing measurements, is implemented by a fixed number of cortical neurons.

  6. Massive cortical reorganization in sighted Braille readers

    Science.gov (United States)

    Siuda-Krzywicka, Katarzyna; Bola, Łukasz; Paplińska, Małgorzata; Sumera, Ewa; Jednoróg, Katarzyna; Marchewka, Artur; Śliwińska, Magdalena W; Amedi, Amir; Szwed, Marcin

    2016-01-01

    The brain is capable of large-scale reorganization in blindness or after massive injury. Such reorganization crosses the division into separate sensory cortices (visual, somatosensory...). As its result, the visual cortex of the blind becomes active during tactile Braille reading. Although the possibility of such reorganization in the normal, adult brain has been raised, definitive evidence has been lacking. Here, we demonstrate such extensive reorganization in normal, sighted adults who learned Braille while their brain activity was investigated with fMRI and transcranial magnetic stimulation (TMS). Subjects showed enhanced activity for tactile reading in the visual cortex, including the visual word form area (VWFA) that was modulated by their Braille reading speed and strengthened resting-state connectivity between visual and somatosensory cortices. Moreover, TMS disruption of VWFA activity decreased their tactile reading accuracy. Our results indicate that large-scale reorganization is a viable mechanism recruited when learning complex skills. DOI: http://dx.doi.org/10.7554/eLife.10762.001 PMID:26976813

  7. Cable energy function of cortical axons.

    Science.gov (United States)

    Ju, Huiwen; Hines, Michael L; Yu, Yuguo

    2016-01-01

    Accurate estimation of action potential (AP)-related metabolic cost is essential for understanding energetic constraints on brain connections and signaling processes. Most previous energy estimates of the AP were obtained using the Na(+)-counting method, which seriously limits accurate assessment of metabolic cost of ionic currents that underlie AP conduction along the axon. Here, we first derive a full cable energy function for cortical axons based on classic Hodgkin-Huxley (HH) neuronal equations and then apply the cable energy function to precisely estimate the energy consumption of AP conduction along axons with different geometric shapes. Our analytical approach predicts an inhomogeneous distribution of metabolic cost along an axon with either uniformly or nonuniformly distributed ion channels. The results show that the Na(+)-counting method severely underestimates energy cost in the cable model by 20-70%. AP propagation along axons that differ in length may require over 15% more energy per unit of axon area than that required by a point model. However, actual energy cost can vary greatly depending on axonal branching complexity, ion channel density distributions, and AP conduction states. We also infer that the metabolic rate (i.e. energy consumption rate) of cortical axonal branches as a function of spatial volume exhibits a 3/4 power law relationship.

  8. Cortical deafness to dissonance.

    Science.gov (United States)

    Peretz, I; Blood, A J; Penhune, V; Zatorre, R

    2001-05-01

    Ordinary listeners, including infants, easily distinguish consonant from dissonant pitch combinations and consider the former more pleasant than the latter. The preference for consonance over dissonance was tested in a patient, I.R., who suffers from music perception and memory disorders as a result of bilateral lesions to the auditory cortex. In Experiment 1, I.R. was found to be unable to distinguish consonant from dissonant versions of musical excerpts taken from the classical repertoire by rating their pleasantness. I.R.'s indifference to dissonance was not due to a loss of all affective responses to music, however, since she rated the same excerpts as happy or sad, as normal controls do. In Experiment 2, I.R.'s lack of responsiveness to varying degrees of dissonance was replicated with chord sequences which had been used in a previous study using PET, in examining emotional responses to dissonance. A CT scan of I.R.'s brain was co-registered with the PET activation data from normal volunteers. Comparison of I.R.'s scan with the PET data revealed that the damaged areas overlapped with the regions identified to be involved in the perceptual analysis of the musical input, but not with the paralimbic regions involved in affective responses. Taken together, the findings suggest that dissonance may be computed bilaterally in the superior temporal gyri by specialized mechanisms prior to its emotional interpretation.

  9. Theory of cortical function.

    Science.gov (United States)

    Heeger, David J

    2017-02-21

    Most models of sensory processing in the brain have a feedforward architecture in which each stage comprises simple linear filtering operations and nonlinearities. Models of this form have been used to explain a wide range of neurophysiological and psychophysical data, and many recent successes in artificial intelligence (with deep convolutional neural nets) are based on this architecture. However, neocortex is not a feedforward architecture. This paper proposes a first step toward an alternative computational framework in which neural activity in each brain area depends on a combination of feedforward drive (bottom-up from the previous processing stage), feedback drive (top-down context from the next stage), and prior drive (expectation). The relative contributions of feedforward drive, feedback drive, and prior drive are controlled by a handful of state parameters, which I hypothesize correspond to neuromodulators and oscillatory activity. In some states, neural responses are dominated by the feedforward drive and the theory is identical to a conventional feedforward model, thereby preserving all of the desirable features of those models. In other states, the theory is a generative model that constructs a sensory representation from an abstract representation, like memory recall. In still other states, the theory combines prior expectation with sensory input, explores different possible perceptual interpretations of ambiguous sensory inputs, and predicts forward in time. The theory, therefore, offers an empirically testable framework for understanding how the cortex accomplishes inference, exploration, and prediction.

  10. Motor cortical thresholds and cortical silent periods in epilepsy.

    Science.gov (United States)

    Tataroglu, Cengiz; Ozkiziltan, Safa; Baklan, Baris

    2004-10-01

    We studied motor cortical thresholds (TIs) and cortical silent periods (SPs) evoked by transcranial magnetic stimulation (TMS) in 110 epileptic patients. Sixty-two had primary generalised, 48 had partial type seizures. Fifteen out 110 patients were analysed both before and after anticonvulsant medication. Our aims were to evaluate the TI levels and the duration of SPs in patients with epilepsy and to determine the reliability of TMS in patients with epilepsy. There was no negative effect of TMS on the clinical status and EEG findings in patients with epilepsy. TIs obtained from patients with partial epilepsy were higher than those obtained from both controls and primary epileptics. The duration of SP in patients with primary epileptics was more prolonged than those obtained from controls. There was no correlation between EEG lateralisation and both SP duration and TI values. In de novo patient group, SP duration was significantly prolonged after anticonvulsant medication. We concluded that TMS is a reliable electrophysiological investigation in patients with epilepsy. The analysis of SP duration may be an appropriate investigation in monitoring the effect of anticonvulsant medication on the cortical inhibitory activity.

  11. Cortical activity during rotational and linear transformations.

    Science.gov (United States)

    Barnes, J; Howard, R J; Senior, C; Brammer, M; Bullmore, E T; Simmons, A; Woodruff, P; David, A S

    2000-01-01

    Neuroimaging studies of cortical activation during image transformation tasks have shown that mental rotation may rely on similar brain regions as those underlying visual perceptual mechanisms. The V5 complex, which is specialised for visual motion, is one region that has been implicated. We used functional magnetic resonance imaging (fMRI) to investigate rotational and linear transformation of stimuli. Areas of significant brain activation were identified for each of the primary mental transformation tasks in contrast to its own perceptual reference task which was cognitively matched in all respects except for the variable of interest. Analysis of group data for perception of rotational and linear motion showed activation in areas corresponding to V5 as defined in earlier studies. Both rotational and linear mental transformations activated Brodman Area (BA) 19 but did not activate V5. An area within the inferior temporal gyrus, representing an inferior satellite area of V5, was activated by both the rotational perception and rotational transformation tasks, but showed no activation in response to linear motion perception or transformation. The findings demonstrate the extent to which neural substrates for image transformation and perception overlap and are distinct as well as revealing functional specialisation within perception and transformation processing systems.

  12. Exploring the cortical evidence of a sensory-discrimination process.

    Science.gov (United States)

    Romo, Ranulfo; Hernández, Adrián; Zainos, Antonio; Brody, Carlos; Salinas, Emilio

    2002-01-01

    Humans and monkeys have similar abilities to discriminate the difference in frequency between two consecutive mechanical vibrations applied to their fingertips. This task can be conceived as a chain of neural operations: encoding the two consecutive stimuli, maintaining the first stimulus in working memory, comparing the second stimulus with the memory trace left by the first stimulus and communicating the result of the comparison to the motor apparatus. We studied this chain of neural operations by recording and manipulating neurons from different areas of the cerebral cortex while monkeys performed the task. The results indicate that neurons of the primary somatosensory cortex (S1) generate a neural representation of vibrotactile stimuli which correlates closely with psychophysical performance. Discrimination based on microstimulation patterns injected into clusters of S1 neurons is indistinguishable from that produced by natural stimuli. Neurons from the secondary somatosensory cortex (S2), prefrontal cortex and medial premotor cortex (MPC) display at different times the trace of the first stimulus during the working-memory component of the task. Neurons from S2 and MPC appear to show the comparison between the two stimuli and correlate with the behavioural decisions. These neural operations may contribute to the sensory-discrimination process studied here. PMID:12217172

  13. Vestibular-related frontal cortical areas and their roles in smooth-pursuit eye movements: representation of neck velocity, neck-vestibular interactions and memory-based smooth-pursuit

    Directory of Open Access Journals (Sweden)

    Kikuro eFukushima

    2011-12-01

    Full Text Available Smooth-pursuit eye movements are voluntary responses to small slow-moving objects in the fronto-parallel plane. They evolved in primates, who possess high-acuity foveae, to ensure clear vision about the moving target. The primate frontal cortex contains two smooth-pursuit related areas; the caudal part of the frontal eye fields (FEF and the supplementary eye fields (SEF. Both areas receive vestibular inputs. We review functional differences between the two areas in smooth-pursuit. Most FEF pursuit neurons signal pursuit parameters such as eye velocity and gaze-velocity, and are involved in cancelling the vestibulo-ocular reflex by linear addition of vestibular and smooth-pursuit responses. In contrast, gaze-velocity signals are rarely represented in the SEF. Most FEF pursuit neurons receive neck velocity inputs, while discharge modulation during pursuit and trunk-on-head rotation adds linearly. Linear addition also occurs between neck velocity responses and vestibular responses during head-on-trunk rotation in a task-dependent manner. During cross-axis pursuit-vestibular interactions, vestibular signals effectively initiate predictive pursuit eye movements. Most FEF pursuit neurons discharge during the interaction training after the onset of pursuit eye velocity, making their involvement unlikely in the initial stages of generating predictive pursuit. Comparison of representative signals in the two areas and the results of chemical inactivation during a memory-based smooth-pursuit task indicate they have different roles; the SEF plans smooth-pursuit including working memory of motion-direction, whereas the caudal FEF generates motor commands for pursuit eye movements. Patients with idiopathic Parkinson’s disease were asked to perform this task, since impaired smooth-pursuit and visual working memory deficit during cognitive tasks have been reported in most patients. Preliminary results suggested specific roles of the basal ganglia in memory

  14. Environmental enrichment modulates cortico-cortical interactions in the mouse.

    Directory of Open Access Journals (Sweden)

    Angelo Di Garbo

    Full Text Available Environmental enrichment (EE is an experimental protocol based on a complex sensorimotor stimulation that dramatically affects brain development. While it is widely believed that the effects of EE result from the unique combination of different sensory and motor stimuli, it is not known whether and how cortico-cortical interactions are shaped by EE. Since the primary visual cortex (V1 is one of the best characterized targets of EE, we looked for direct cortico-cortical projections impinging on V1, and we identified a direct monosynaptic connection between motor cortex and V1 in the mouse brain. To measure the interactions between these areas under standard and EE rearing conditions, we used simultaneous recordings of local field potentials (LFPs in awake, freely moving animals. LFP signals were analyzed by using different methods of linear and nonlinear analysis of time series (cross-correlation, mutual information, phase synchronization. We found that EE decreases the level of coupling between the electrical activities of the two cortical regions with respect to the control group. From a functional point of view, our results indicate, for the first time, that an enhanced sensorimotor experience impacts on the brain by affecting the functional crosstalk between different cortical areas.

  15. High-expanding cortical regions in human development and evolution are related to higher intellectual abilities.

    Science.gov (United States)

    Fjell, Anders M; Westlye, Lars T; Amlien, Inge; Tamnes, Christian K; Grydeland, Håkon; Engvig, Andreas; Espeseth, Thomas; Reinvang, Ivar; Lundervold, Astri J; Lundervold, Arvid; Walhovd, Kristine B

    2015-01-01

    Cortical surface area has tremendously expanded during human evolution, and similar patterns of cortical expansion have been observed during childhood development. An intriguing hypothesis is that the high-expanding cortical regions also show the strongest correlations with intellectual function in humans. However, we do not know how the regional distribution of correlations between intellectual function and cortical area maps onto expansion in development and evolution. Here, in a sample of 1048 participants, we show that regions in which cortical area correlates with visuospatial reasoning abilities are generally high expanding in both development and evolution. Several regions in the frontal cortex, especially the anterior cingulate, showed high expansion in both development and evolution. The area of these regions was related to intellectual functions in humans. Low-expanding areas were not related to cognitive scores. These findings suggest that cortical regions involved in higher intellectual functions have expanded the most during development and evolution. The radial unit hypothesis provides a common framework for interpretation of the findings in the context of evolution and prenatal development, while additional cellular mechanisms, such as synaptogenesis, gliogenesis, dendritic arborization, and intracortical myelination, likely impact area expansion in later childhood.

  16. Predicting the connectivity of primate cortical networks from topological and spatial node properties

    Directory of Open Access Journals (Sweden)

    Kaiser Marcus

    2007-03-01

    Full Text Available Abstract Background The organization of the connectivity between mammalian cortical areas has become a major subject of study, because of its important role in scaffolding the macroscopic aspects of animal behavior and intelligence. In this study we present a computational reconstruction approach to the problem of network organization, by considering the topological and spatial features of each area in the primate cerebral cortex as subsidy for the reconstruction of the global cortical network connectivity. Starting with all areas being disconnected, pairs of areas with similar sets of features are linked together, in an attempt to recover the original network structure. Results Inferring primate cortical connectivity from the properties of the nodes, remarkably good reconstructions of the global network organization could be obtained, with the topological features allowing slightly superior accuracy to the spatial ones. Analogous reconstruction attempts for the C. elegans neuronal network resulted in substantially poorer recovery, indicating that cortical area interconnections are relatively stronger related to the considered topological and spatial properties than neuronal projections in the nematode. Conclusion The close relationship between area-based features and global connectivity may hint on developmental rules and constraints for cortical networks. Particularly, differences between the predictions from topological and spatial properties, together with the poorer recovery resulting from spatial properties, indicate that the organization of cortical networks is not entirely determined by spatial constraints.

  17. Imprinting and recalling cortical ensembles.

    Science.gov (United States)

    Carrillo-Reid, Luis; Yang, Weijian; Bando, Yuki; Peterka, Darcy S; Yuste, Rafael

    2016-08-12

    Neuronal ensembles are coactive groups of neurons that may represent building blocks of cortical circuits. These ensembles could be formed by Hebbian plasticity, whereby synapses between coactive neurons are strengthened. Here we report that repetitive activation with two-photon optogenetics of neuronal populations from ensembles in the visual cortex of awake mice builds neuronal ensembles that recur spontaneously after being imprinted and do not disrupt preexisting ones. Moreover, imprinted ensembles can be recalled by single- cell stimulation and remain coactive on consecutive days. Our results demonstrate the persistent reconfiguration of cortical circuits by two-photon optogenetics into neuronal ensembles that can perform pattern completion. Copyright © 2016, American Association for the Advancement of Science.

  18. Cortical sensorimotor integration: a hypothesis.

    Science.gov (United States)

    Batuev, A S

    1989-01-01

    A hypothesis is proposed that neocortex is constructed from structural neuronal modules (columns and rings). Each module is considered as unit for cortical sensorimotor integration. Complex functional relationships between modules can be arranged by intracortical inhibition participation. High pronounced neocortical plasticity ensures the process of continuous formation of various dominating operative constellations comprising stable neuronal modules whose component structure and distributive characteristic are determined by the dominant motivation and the central motor program.

  19. Human cerebral cortices: signal variation on diffusion-weighted MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Asao, Chiaki [Kumamoto Regional Medical Center, Department of Radiology, Kumamoto (Japan); National Hospital Organization Kumamoto Medical Center, Department of Radiology, Kumamoto (Japan); Hirai, Toshinori; Yamashita, Yasuyuki [Kumamoto University Graduate School of Medical Sciences, Department of Diagnostic Radiology, Kumamoto (Japan); Yoshimatsu, Shunji [National Hospital Organization Kumamoto Medical Center, Department of Radiology, Kumamoto (Japan); Matsukawa, Tetsuya; Imuta, Masanori [Kumamoto Regional Medical Center, Department of Radiology, Kumamoto (Japan); Sagara, Katsuro [Kumamoto Regional Medical Center, Department of Internal Medicine, Kumamoto (Japan)

    2008-03-15

    We have often encountered high signal intensity (SI) of the cingulate gyrus and insula during diffusion-weighted magnetic resonance imaging (DW-MRI) on neurologically healthy adults. To date, cortical signal heterogeneity on DW images has not been investigated systematically. The purpose of our study was to determine whether there is regional signal variation in the brain cortices of neurologically healthy adults on DW-MR images. The SI of the cerebral cortices on DW-MR images at 1.5 T was evaluated in 50 neurologically healthy subjects (34 men, 16 women; age range 33-84 years; mean age 57.6 years). The cortical SI in the cingulate gyrus, insula, and temporal, occipital, and parietal lobes was graded relative to the SI of the frontal lobe. Contrast-to-noise ratios (CNRs) on DW-MR images were compared for each cortical area. Diffusion changes were analyzed by visually assessment of the differences in appearance among the cortices on apparent diffusion coefficient (ADC) maps. Increased SI was frequently seen in the cingulate gyrus and insula regardless of patient age. There were no significant gender- or laterality-related differences. The CNR was significantly higher in the cingulate gyrus and insula than in the other cortices (p <.01), and significant differences existed among the cortical regions (p <.001). There were no apparent ADC differences among the cortices on ADC maps. Regional signal variation of the brain cortices was observed on DW-MR images of healthy subjects, and the cingulate gyrus and insula frequently manifested high SI. These findings may help in the recognition of cortical signal abnormalities as visualized on DW-MR images. (orig.)

  20. [Parietal Cortices and Body Information].

    Science.gov (United States)

    Naito, Eiichi; Amemiya, Kaoru; Morita, Tomoyo

    2016-11-01

    Proprioceptive signals originating from skeletal muscles and joints contribute to the formation of both the human body schema and the body image. In this chapter, we introduce various types of bodily illusions that are elicited by proprioceptive inputs, and we discuss distinct functions implemented by different parietal cortices. First, we illustrate the primary importance of the motor network in the processing of proprioceptive (kinesthetic) signals originating from muscle spindles. Next, we argue that the right inferior parietal cortex, in concert with the inferior frontal cortex (both regions connected by the inferior branch of the superior longitudinal fasciculus-SLF III), may be involved in the conscious experience of body image. Further, we hypothesize other functions of distinct parietal regions: the association between internal hand motor representation with external object representation in the left inferior parietal cortex, visuo-kinesthetic processing in the bilateral posterior parietal cortices, and the integration of somatic signals from different body parts in the higher-order somatosensory parietal cortices. Our results indicate that a distinct parietal region, in concert with its anatomically and functionally connected frontal regions, probably plays specialized roles in the processing of body-related information.

  1. Study of the relationship between the acupoints of Zhongzhu(TE 3),Yanglingquan (GB 34) and their corresponding cortical areas with the functional MRI%中渚、阳陵泉穴与脑功能区的关系:功能性磁共振成像研究

    Institute of Scientific and Technical Information of China (English)

    田丽芳; 周诚; 陈敏; 邹明珠; 杨正汉

    2009-01-01

    Objective Using the functional magnetic resonance imaging (fMRI) to observe the distributed characteristic of excited cerebral cortical areas that induced by acupuncture-stimulating the Zhongzhu (TE 3) of the meridian of Hand-Shaoyang and Yanglingquan (GB 34) of the meridian of Foot-Shaoyang, and investigate the central neural mechanism on the effect of meridians and acupoints. Methods Forty-two right-handed healthy volunteers were randomly divided into Zhongzhu (TE 3) group and Yanglingquan (GB 34) group. The functional cortical changes during acupuncture-stimulating the Zhongzhu (TE 3) and Yanglingquan (GB 34) were successively scanned with fMRI, and the effected areas were determined through analysing the obtained data with SPM2 software. Results The main excited areas were bilateral frontal lobes, temporal lobes, cerebellum and occipital lobes successively in Zhongzhu (TE 3) group, and bilateral occipital lobes, cerebellum, frontal lobes and temporal lobes in Yanglingquan (GB 34) group in contrast. Conclusion Acupuncture-stimulating both Zhongzhu (TE 3) and Yanglingquan (GB 34) can excite bilateral acoustic, visual and somatomotor cortices, which might be the central neural basis for clinical treatment on related diseases.%目的:运用功能性磁共振成像技术(fMRI)观察针刺手少阳经中渚穴和足少阳经阳陵泉穴时大脑皮层兴奋区的分布特点,初步探讨经络、穴位作用的中枢机制.方法:将42例健康受试者(右利手),随机分为针刺中渚穴和阳陵泉穴两组.采用fMRI技术实时动态扫描针刺中渚穴和阳陵泉穴时脑功能区的变化,最终所获得的数据采用SPM2软件包分析其作用部位.结果:中渚穴引起的脑内主要兴奋区依次为双侧的额叶、颞叶、小脑和枕叶,阳陵泉穴引起的主要兴奋区依次为双侧的枕叶、小脑、额叶和颞叶.结论:针刺中渚穴和阳陵泉穴时均可以引起双侧听觉、视觉相关大脑皮质和

  2. TMS-induced cortical potentiation during wakefulness locally increases slow wave activity during sleep.

    Directory of Open Access Journals (Sweden)

    Reto Huber

    Full Text Available BACKGROUND: Sleep slow wave activity (SWA is thought to reflect sleep need, increasing in proportion to the length of prior wakefulness and decreasing during sleep. However, the process responsible for SWA regulation is not known. We showed recently that SWA increases locally after a learning task involving a circumscribed brain region, suggesting that SWA may reflect plastic changes triggered by learning. METHODOLOGY/PRINCIPAL FINDINGS: To test this hypothesis directly, we used transcranial magnetic stimulation (TMS in conjunction with high-density EEG in humans. We show that 5-Hz TMS applied to motor cortex induces a localized potentiation of TMS-evoked cortical EEG responses. We then show that, in the sleep episode following 5-Hz TMS, SWA increases markedly (+39.1+/-17.4%, p<0.01, n = 10. Electrode coregistration with magnetic resonance images localized the increase in SWA to the same premotor site as the maximum TMS-induced potentiation during wakefulness. Moreover, the magnitude of potentiation during wakefulness predicts the local increase in SWA during sleep. CONCLUSIONS/SIGNIFICANCE: These results provide direct evidence for a link between plastic changes and the local regulation of sleep need.

  3. Optimal sensorimotor integration in recurrent cortical networks: a neural implementation of Kalman filters.

    Science.gov (United States)

    Denève, Sophie; Duhamel, Jean-René; Pouget, Alexandre

    2007-05-23

    Several behavioral experiments suggest that the nervous system uses an internal model of the dynamics of the body to implement a close approximation to a Kalman filter. This filter can be used to perform a variety of tasks nearly optimally, such as predicting the sensory consequence of motor action, integrating sensory and body posture signals, and computing motor commands. We propose that the neural implementation of this Kalman filter involves recurrent basis function networks with attractor dynamics, a kind of architecture that can be readily mapped onto cortical circuits. In such networks, the tuning curves to variables such as arm velocity are remarkably noninvariant in the sense that the amplitude and width of the tuning curves of a given neuron can vary greatly depending on other variables such as the position of the arm or the reliability of the sensory feedback. This property could explain some puzzling properties of tuning curves in the motor and premotor cortex, and it leads to several new predictions.

  4. Cortical Motor Organization, Mirror Neurons, and Embodied Language: An Evolutionary Perspective

    Directory of Open Access Journals (Sweden)

    Leonardo Fogassi

    2012-11-01

    Full Text Available The recent conceptual achievement that the cortical motor system plays a crucial role not only in motor control but also in higher cognitive functions has given a new perspective also on the involvement of motor cortex in language perception and production. In particular, there is evidence that the matching mechanism based on mirror neurons can be involved in both pho-nological recognition and retrieval of meaning, especially for action word categories, thus suggesting a contribution of an action–perception mechanism to the automatic comprehension of semantics. Furthermore, a compari-son of the anatomo-functional properties of the frontal motor cortex among different primates and their communicative modalities indicates that the combination of the voluntary control of the gestural communication systems and of the vocal apparatus has been the critical factor in the transition from a gestural-based communication into a predominantly speech-based system. Finally, considering that the monkey and human premotor-parietal motor system, plus the prefrontal cortex, are involved in the sequential motor organization of actions and in the hierarchical combination of motor elements, we propose that elements of such motor organization have been exploited in other domains, including some aspects of the syntactic structure of language.

  5. Control of Somatosensory Cortical Processing by Thalamic Posterior Medial Nucleus: A New Role of Thalamus in Cortical Function.

    Directory of Open Access Journals (Sweden)

    Carlos Castejon

    Full Text Available Current knowledge of thalamocortical interaction comes mainly from studying lemniscal thalamic systems. Less is known about paralemniscal thalamic nuclei function. In the vibrissae system, the posterior medial nucleus (POm is the corresponding paralemniscal nucleus. POm neurons project to L1 and L5A of the primary somatosensory cortex (S1 in the rat brain. It is known that L1 modifies sensory-evoked responses through control of intracortical excitability suggesting that L1 exerts an influence on whisker responses. Therefore, thalamocortical pathways targeting L1 could modulate cortical firing. Here, using a combination of electrophysiology and pharmacology in vivo, we have sought to determine how POm influences cortical processing. In our experiments, single unit recordings performed in urethane-anesthetized rats showed that POm imposes precise control on the magnitude and duration of supra- and infragranular barrel cortex whisker responses. Our findings demonstrated that L1 inputs from POm imposed a time and intensity dependent regulation on cortical sensory processing. Moreover, we found that blocking L1 GABAergic inhibition or blocking P/Q-type Ca2+ channels in L1 prevents POm adjustment of whisker responses in the barrel cortex. Additionally, we found that POm was also controlling the sensory processing in S2 and this regulation was modulated by corticofugal activity from L5 in S1. Taken together, our data demonstrate the determinant role exerted by the POm in the adjustment of somatosensory cortical processing and in the regulation of cortical processing between S1 and S2. We propose that this adjustment could be a thalamocortical gain regulation mechanism also present in the processing of information between cortical areas.

  6. Control of Somatosensory Cortical Processing by Thalamic Posterior Medial Nucleus: A New Role of Thalamus in Cortical Function

    Science.gov (United States)

    Castejon, Carlos; Barros-Zulaica, Natali; Nuñez, Angel

    2016-01-01

    Current knowledge of thalamocortical interaction comes mainly from studying lemniscal thalamic systems. Less is known about paralemniscal thalamic nuclei function. In the vibrissae system, the posterior medial nucleus (POm) is the corresponding paralemniscal nucleus. POm neurons project to L1 and L5A of the primary somatosensory cortex (S1) in the rat brain. It is known that L1 modifies sensory-evoked responses through control of intracortical excitability suggesting that L1 exerts an influence on whisker responses. Therefore, thalamocortical pathways targeting L1 could modulate cortical firing. Here, using a combination of electrophysiology and pharmacology in vivo, we have sought to determine how POm influences cortical processing. In our experiments, single unit recordings performed in urethane-anesthetized rats showed that POm imposes precise control on the magnitude and duration of supra- and infragranular barrel cortex whisker responses. Our findings demonstrated that L1 inputs from POm imposed a time and intensity dependent regulation on cortical sensory processing. Moreover, we found that blocking L1 GABAergic inhibition or blocking P/Q-type Ca2+ channels in L1 prevents POm adjustment of whisker responses in the barrel cortex. Additionally, we found that POm was also controlling the sensory processing in S2 and this regulation was modulated by corticofugal activity from L5 in S1. Taken together, our data demonstrate the determinant role exerted by the POm in the adjustment of somatosensory cortical processing and in the regulation of cortical processing between S1 and S2. We propose that this adjustment could be a thalamocortical gain regulation mechanism also present in the processing of information between cortical areas. PMID:26820514

  7. Functional MRI activation of primary and secondary motor areas in healthy subjects

    Institute of Scientific and Technical Information of China (English)

    Donghai Li; Honghan Gong; Xiangzuo Xiao; Jinhua Wan

    2008-01-01

    images.Active signal changes in the primary(M1)and secondary motor(M2)areas,as well as the relationship between the hand knobs and M1 area activation,were analyzed.Region of interest was selected for signal change quantitative graphic analysis.RESULTS:All 7 enrolled volunteers were included in the final analysis.In the present study,hand knob structures were recognized on Tl-weighted images in all subjects and were omega-shaped in the axial plane.Significant functional activations were observed in the contralateral primary motor area of all subjects. Activation signals were distributed mainly in the central sulcus around the hand knob.The contralateral primary sensory(S1)cortex was activated in most cases,and ipsilateral M1 was activated in 3 subjects. Contralateral or bilateral supplementary motor area(SMA)was also activated in 6 cases.Premotor area,or super parietal lobe,was activated in two subjects.Three-dimensional reconstruction demonstrated that the active signal of M1 was primarily located at the middle-lateral surface of the contralateral precentral gyrus in Brodman's area 4,and the signal of SMA activation was located in the mesial surface of the premotor area. CONCLUSION:The knob structure of the precentral gyrus is the representative motor area for hand movement.The cerebral cortical motor network was extensively activated during voluntary hand movements in normal subjects.In alert,conscious human subjects,the activated fMRI signal safely and non-invasively localized and lateralized the motor cortical activity associated with simple voluntary repetitive hand movements.Whether higher cognitive functions,such as perception and speech,can be similarly mapped using the fMRI technique and the BOLD method remains to be determined in future well-designed human studies.

  8. Age-Dependent Cortical Thinning of Peripheral Visual Field Representations in Primary Visual Cortex.

    Science.gov (United States)

    Griffis, Joseph C; Burge, Wesley K; Visscher, Kristina M

    2016-01-01

    The cerebral cortex changes throughout the lifespan, and the cortical gray matter in many brain regions becomes thinner with advancing age. Effects of aging on cortical thickness (CT) have been observed in many brain regions, including areas involved in basic perceptual functions such as processing visual inputs. An important property of early visual cortices is their topographic organization-the cortical structure of early visual areas forms a topographic map of retinal inputs. Primary visual cortex (V1) is considered to be the most basic cortical area in the visual processing hierarchy, and is topographically organized from posterior (central visual representation) to anterior (peripheral visual representation) along the calcarine sulcus. Some studies have reported strong age-dependent cortical thinning in portions of V1 that likely correspond to peripheral visual representations, while there is less evidence of substantial cortical thinning in central V1. However, the effect of aging on CT in V1 as a function of its topography has not been directly investigated. To address this gap in the literature, we estimated the CT of different eccentricity sectors in V1 using T1-weighted MRI scans acquired from groups of healthy younger and older adults, and then assessed whether between-group differences in V1 CT depended on cortical eccentricity. These analyses revealed age-dependent cortical thinning specific to peripheral visual field representations in anterior portions of V1, but did not provide evidence for age-dependent cortical thinning in other portions of V1. Additional analyses found similar effects when analyses were restricted to the gyral crown, sulcul depth and sulcul wall, indicating that these effects are not likely due to differences in gyral/sulcul contributions to our regions of interest (ROI). Importantly, this finding indicates that age-dependent changes in cortical structure may differ among functionally distinct zones within larger canonical

  9. Early detection of AD using cortical thickness measurements

    Science.gov (United States)

    Spjuth, M.; Gravesen, F.; Eskildsen, S. F.; Østergaard, L. R.

    2007-03-01

    Alzheimer's disease (AD) is a neurodegenerative disorder that causes cortical atrophy and impaired cognitive functions. The diagnosis is difficult to make and is often made over a longer period of time using a combination of neuropsychological tests, and structural and functional imaging. Due to the impact of early intervention the challenge of distinguishing early AD from normal ageing has received increasing attention. This study uses cortical thickness measurements to characterize the atrophy in nine mild AD patients (mean MMSE-score 23.3 (std: 2.6)) compared to five healthy middle-aged subjects. A fully automated method based on deformable models is used for delineation of the inner and outer boundaries of the cerebral cortex from Magnetic Resonance Images. This allows observer independent high-resolution quantification of the cortical thickness. The cortex analysis facilitates detection of alterations throughout the entire cortical mantle. To perform inter-subject thickness comparison in which the spatial information is retained, a feature-based registration algorithm is developed which uses local cortical curvature, normal vector, and a distance measure. A comparison of the two study groups reveals that the lateral side of the hemispheres shows diffuse thinner areas in the mild AD group but especially the medial side shows a pronounced thinner area which can be explained by early limbic changes in AD. For classification principal component analysis is applied to reduce the high number of thickness measurements (>200,000) into fewer features. All mild AD and healthy middle-aged subjects are classified correctly (sensitivity and specificity 100%).

  10. Associations between cortical thickness and verbal fluency in childhood, adolescence, and young adulthood.

    Science.gov (United States)

    Porter, James N; Collins, Paul F; Muetzel, Ryan L; Lim, Kelvin O; Luciana, Monica

    2011-04-15

    Neuroimaging studies of normative human brain development indicate that the brain matures at differing rates across time and brain regions, with some areas maturing into young adulthood. In particular, changes in cortical thickness may index maturational progressions from an overabundance of neuropil toward efficiently pruned neural networks. Developmental changes in structural MRI measures have rarely been examined in relation to discrete neuropsychological functions. In this study, healthy right-handed adolescents completed MRI scanning and the Controlled Oral Word Association Test (COWAT). Associations of task performance and cortical thickness were assessed with cortical-surface-based analyses. Significant correlations between increasing COWAT performances and decreasing cortical thickness were found in left hemisphere language regions, including perisylvian regions surrounding Wernicke's and Broca's areas. Task performance was also correlated with regions associated with effortful verbal processing, working memory, and performance monitoring. Structure-function associations were not significantly different between older and younger subjects. Decreases in cortical thicknesses in regions that comprise the language network likely reflect maturation toward adult-like cortical organization and processing efficiency. The changes in cortical thicknesses that support verbal fluency are apparent by middle childhood, but with regionally separate developmental trajectories for males and females, consistent with other studies of adolescent development.

  11. The cortical hem regulates the size and patterning of neocortex.

    Science.gov (United States)

    Caronia-Brown, Giuliana; Yoshida, Michio; Gulden, Forrest; Assimacopoulos, Stavroula; Grove, Elizabeth A

    2014-07-01

    The cortical hem, a source of Wingless-related (WNT) and bone morphogenetic protein (BMP) signaling in the dorsomedial telencephalon, is the embryonic organizer for the hippocampus. Whether the hem is a major regulator of cortical patterning outside the hippocampus has not been investigated. We examined regional organization across the entire cerebral cortex in mice genetically engineered to lack the hem. Indicating that the hem regulates dorsoventral patterning in the cortical hemisphere, the neocortex, particularly dorsomedial neocortex, was reduced in size in late-stage hem-ablated embryos, whereas cortex ventrolateral to the neocortex expanded dorsally. Unexpectedly, hem ablation also perturbed regional patterning along the rostrocaudal axis of neocortex. Rostral neocortical domains identified by characteristic gene expression were expanded, and caudal domains diminished. A similar shift occurs when fibroblast growth factor (FGF) 8 is increased at the rostral telencephalic organizer, yet the FGF8 source was unchanged in hem-ablated brains. Rather we found that hem WNT or BMP signals, or both, have opposite effects to those of FGF8 in regulating transcription factors that control the size and position of neocortical areas. When the hem is ablated a necessary balance is perturbed, and cerebral cortex is rostralized. Our findings reveal a much broader role for the hem in cortical development than previously recognized, and emphasize that two major signaling centers interact antagonistically to pattern cerebral cortex.

  12. Hamilton-Jacobi skeleton on cortical surfaces.

    Science.gov (United States)

    Shi, Y; Thompson, P M; Dinov, I; Toga, A W

    2008-05-01

    In this paper, we propose a new method to construct graphical representations of cortical folding patterns by computing skeletons on triangulated cortical surfaces. In our approach, a cortical surface is first partitioned into sulcal and gyral regions via the solution of a variational problem using graph cuts, which can guarantee global optimality. After that, we extend the method of Hamilton-Jacobi skeleton [1] to subsets of triangulated surfaces, together with a geometrically intuitive pruning process that can trade off between skeleton complexity and the completeness of representing folding patterns. Compared with previous work that uses skeletons of 3-D volumes to represent sulcal patterns, the skeletons on cortical surfaces can be easily decomposed into branches and provide a simpler way to construct graphical representations of cortical morphometry. In our experiments, we demonstrate our method on two different cortical surface models, its ability of capturing major sulcal patterns and its application to compute skeletons of gyral regions.

  13. Disorders of cortical formation: MR imaging features.

    Science.gov (United States)

    Abdel Razek, A A K; Kandell, A Y; Elsorogy, L G; Elmongy, A; Basett, A A

    2009-01-01

    The purpose of this article was to review the embryologic stages of the cerebral cortex, illustrate the classification of disorders of cortical formation, and finally describe the main MR imaging features of these disorders. Disorders of cortical formation are classified according to the embryologic stage of the cerebral cortex at which the abnormality occurred. MR imaging shows diminished cortical thickness and sulcation in microcephaly, enlarged dysplastic cortex in hemimegalencephaly, and ipsilateral focal cortical thickening with radial hyperintense bands in focal cortical dysplasia. MR imaging detects smooth brain in classic lissencephaly, the nodular cortex with cobblestone cortex with congenital muscular dystrophy, and the ectopic position of the gray matter with heterotopias. MR imaging can detect polymicrogyria and related syndromes as well as the types of schizencephaly. We concluded that MR imaging is essential to demonstrate the morphology, distribution, and extent of different disorders of cortical formation as well as the associated anomalies and related syndromes.

  14. A Retrospective Study on Indian Population to evaluate Cortical Bone Thickness in Maxilla and Mandible using Computed Tomography Images

    Directory of Open Access Journals (Sweden)

    Jeegar Ketan Vakil

    2014-01-01

    Conclusion: Mini-implants have gained considerable popularity due to their low cost, effectiveness, clinical management and stability. Among the factors related to microimplant stability, bone density and cortical bone thickness appear to be critical for successful placement. This study will provide knowledge of cortical bone thickness in various areas which can guide the clinicians in selecting the placement site.

  15. Altered cortical causality after remifentanil administration in healthy volunteers

    DEFF Research Database (Denmark)

    Khodayari-Rostamabad, Ahmad; Graversen, Carina; Olesen, Soren S;

    2014-01-01

    being reproducible between the two baseline recordings, several PSI features were altered by remifentanil administration in comparison to placebo. Furthermore, several of the PSI features altered by remifentanil were correlated to changes in both CRT and pain scores. The results indicate...... that remifentanil administration influence the information flow between several brain areas. Hence, the EEG causality approach offers the potential to assist in deciphering the cortical effects of remifentanil administration....

  16. Transient neuropsychological abnormalities (including Gerstmann's syndrome) during cortical stimulation.

    Science.gov (United States)

    Morris, H H; Lüders, H; Lesser, R P; Dinner, D S; Hahn, J

    1984-07-01

    A patient with intractable partial seizures was intensively studied before surgical removal of the epileptogenic focus. A subdural electrode array was surgically placed over the left temporoparietal cortex to better localize the epileptogenic focus and localize cortical function. In addition to speech and sensory findings, acalculia, agraphia, right-left confusion, and finger agnosia were transiently produced by electrical stimulation in the perisylvian area. These findings and their relationship to the controversy surrounding Gerstmann's syndrome are discussed.

  17. A Rare Hydrocephalus Complication: Cortical Blindness.

    Science.gov (United States)

    Ünal, Emre; Göçmen, Rahşan; Işıkay, Ayşe İlksen; Tekşam, Özlem

    2015-01-01

    Cortical blindness related to bilateral occipital lobe infarction is an extremely rare complication of hydrocephalus. Compression of the posterior cerebral artery, secondary to tentorial herniation, is the cause of occipital infarction. Particularly in children and mentally ill patients, cortical blindness may be missed. Therefore, early diagnosis and treatment of hydrocephalus is important. We present herein a child of ventricular shunt malfunction complicated by cortical blindness.

  18. Acute hepatic encephalopathy with diffuse cortical lesions

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, S.M.; Spreer, J.; Schumacher, M. [Section of Neuroradiology, Univ. of Freiburg (Germany); Els, T. [Dept. of Neurology, University of Freiburg (Germany)

    2001-07-01

    Acute hepatic encephalopathy is a poorly defined syndrome of heterogeneous aetiology. We report a 49-year-old woman with alcoholic cirrhosis and hereditary haemorrhagic telangiectasia who developed acute hepatic coma induced by severe gastrointestinal bleeding. Laboratory analysis revealed excessively elevated blood ammonia. MRI showed lesions compatible with chronic hepatic encephalopathy and widespread cortical signal change sparing the perirolandic and occipital cortex. The cortical lesions resembled those of hypoxic brain damage and were interpreted as acute toxic cortical laminar necrosis. (orig.)

  19. INTRAOPERATIVE LOCALIZATION OF CORTICAL MOTOR EVOKED POTENTIALS IN CENTRAL SULCUS LESIONS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective To study direct cortical electrical stimulation technique for the recording of motor evoked potentials under general anesthesia in central sulcus lesions. Methods The largest N20-P25 response was recorded from postcentral gyrus by intraoperative monitoring of cortical motor evoked potentials in 10 patients with intracranial lesions near or in the central area. The muscles of upper extremity in all patients were activated by delivering stimulus to cortical areas continuously. Moving the cortical electrodes forward, the largest P20-N25 response, SEP phase reversal,was obtained as a motor center stimulus. In this site of cortex, a short train stimulation elicited reproducible muscle action potentials that could be observed from the oscilloscope without averaging.Results MEPs can be recorded, pre- and post-operatively, without motor deficits of upper limbs in all patients.Conclusion This technique seems to be preferable for intraoperative localization of motor evoked potentials in central sulcus lesions under total intravenous anesthesia.

  20. Long-Range Cortical Dynamics: A Perspective from the Mouse Sensorimotor Whisker System.

    Science.gov (United States)

    Ni, Jianguang; Chen, Jerry L

    2017-09-16

    In the mammalian neocortex, the capacity to dynamically route and coordinate the exchange of information between areas is a critical feature of cognitive function, enabling processes such as higher-level sensory processing and sensorimotor integration. Despite the importance attributed to long-range connections between cortical areas, their exact operations and role in cortical function remain an open question. In recent years, progress has been made in understanding long-range cortical circuits through work focused on the mouse sensorimotor whisker system. In this review, we examine recent studies dissecting long-range circuits involved in whisker sensorimotor processing as an entry point for understanding the rules that govern long-range cortical circuit function. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  1. Decreased cortical inhibition and yet cerebellar pathology in 'familial cortical myoclonic tremor with epilepsy'

    NARCIS (Netherlands)

    van Rootselaar, Anne-Fleur; van der Salm, Sandra M. A.; Bour, Lo J.; Edwards, Mark J.; Brown, Peter; Aronica, Eleonora; Rozemuller-Kwakkel, Johanna M.; Koehler, Peter J.; Koelman, Johannes H. T. M.; Rothwell, John C.; Tijssen, Marina A. J.

    2007-01-01

    Cortical hyperexcitability is a feature of "familial cortical myoclonic tremor with epilepsy" (FCMTE). However, neuropathological investigations in a single FCMTE patient showed isolated cerebellar pathology. Pathological investigations in a second FCMTE patient, reported here, confirmed cerebellar

  2. Negative Correlations in Visual Cortical Networks

    National Research Council Canada - National Science Library

    Chelaru, Mircea I; Dragoi, Valentin

    2016-01-01

    .... Whereas positive noise correlations have been extensively studied using experimental and theoretical tools, the functional role of negative correlations in cortical circuits has remained elusive...

  3. Changes in neural circuitry associated with depression at pre-clinical, pre-motor and early motor phases of Parkinson's disease.

    Science.gov (United States)

    Borgonovo, Janina; Allende-Castro, Camilo; Laliena, Almudena; Guerrero, Néstor; Silva, Hernán; Concha, Miguel L

    2017-02-01

    Although Parkinson's Disease (PD) is mostly considered a motor disorder, it can present at early stages as a non-motor pathology. Among the non-motor clinical manifestations, depression shows a high prevalence and can be one of the first clinical signs to appear, even a decade before the onset of motor symptoms. Here, we review the evidence of early dysfunction in neural circuitry associated with depression in the context of PD, focusing on pre-clinical, pre-motor and early motor phases of the disease. In the pre-clinical phase, structural and functional changes in the substantia nigra, basal ganglia and limbic structures are already observed. Some of these changes are linked to motor compensation mechanisms while others correspond to pathological processes common to PD and depression and thus could underlie the appearance of depressive symptoms during the pre-motor phase. Studies of the early motor phase (less than five years post diagnosis) reveal an association between the extent of damage in different monoaminergic systems and the appearance of emotional disorders. We propose that the limbic loop of the basal ganglia and the lateral habenula play key roles in the early genesis of depression in PD. Alterations in the neural circuitry linked with emotional control might be sensitive markers of the ongoing neurodegenerative process and thus may serve to facilitate an early diagnosis of this disease. To take advantage of this, we need to improve the clinical criteria and develop biomarkers to identify depression, which could be used to determine individuals at risk to develop PD.

  4. SLEEP AND OLFACTORY CORTICAL PLASTICITY

    Directory of Open Access Journals (Sweden)

    Dylan eBarnes

    2014-04-01

    Full Text Available In many systems, sleep plays a vital role in memory consolidation and synaptic homeostasis. These processes together help store information of biological significance and reset synaptic circuits to facilitate acquisition of information in the future. In this review, we describe recent evidence of sleep-dependent changes in olfactory system structure and function which contribute to odor memory and perception. During slow-wave sleep, the piriform cortex becomes hypo-responsive to odor stimulation and instead displays sharp-wave activity similar to that observed within the hippocampal formation. Furthermore, the functional connectivity between the piriform cortex and other cortical and limbic regions is enhanced during slow-wave sleep compared to waking. This combination of conditions may allow odor memory consolidation to occur during a state of reduced external interference and facilitate association of odor memories with stored hedonic and contextual cues. Evidence consistent with sleep-dependent odor replay within olfactory cortical circuits is presented. These data suggest that both the strength and precision of odor memories is sleep-dependent. The work further emphasizes the critical role of synaptic plasticity and memory in not only odor memory but also basic odor perception. The work also suggests a possible link between sleep disturbances that are frequently co-morbid with a wide range of pathologies including Alzheimer’s disease, schizophrenia and depression and the known olfactory impairments associated with those disorders.

  5. Detecting a cortical fingerprint of Parkinson’s disease for closed-loop neuromodulation

    Directory of Open Access Journals (Sweden)

    Kevin eKern

    2016-03-01

    Full Text Available Recent evidence suggests that deep brain stimulation (DBS of the subthalamic nucleus (STN in Parkinson’s disease (PD mediates its clinical effects by modulating cortical oscillatory activity, presumably via a direct cortico-subthalamic connection. This observation might pave the way for novel closed-loop approaches comprising a cortical sensor. Enhanced beta oscillations (13-35 Hz have been linked to the pathophysiology of PD and may serve as such a candidate marker to localize a cortical area reliably modulated by DBS. However, beta-oscillations are widely distributed over the cortical surface, necessitating an additional signal source for spotting the cortical area linked to the pathologically synchronized cortico-subcortical motor network.In this context, both cortico-subthalamic coherence and cortico-muscular coherence (CMC have been studied in PD patients. Whereas the former requires invasive recordings, the latter allows for non-invasive detection, but displays a rather distributed cortical synchronization pattern in motor tasks. This distributed cortical representation may conflict with the goal of detecting a cortical localization with robust biomarker properties which is detectable on a single subject basis. We propose that this limitation could be overcome when recording CMC at rest. We hypothesized that – unlike healthy subjects – PD would show CMC at rest owing to the enhanced beta oscillations observed in PD. By performing source space analysis of beta CMC recorded during resting-state magnetoencephalography, we provide preliminary evidence in one patient for a cortical hot spot that is modulated most strongly by subthalamic DBS. Such a spot would provide a prominent target region either for direct neuromodulation or for placing a potential sensor in closed-loop DBS approaches, a proposal that requires investigation in a larger cohort of PD patients.

  6. The Cortical Signature of Central Poststroke Pain: Gray Matter Decreases in Somatosensory, Insular, and Prefrontal Cortices.

    Science.gov (United States)

    Krause, T; Asseyer, S; Taskin, B; Flöel, A; Witte, A V; Mueller, K; Fiebach, J B; Villringer, K; Villringer, A; Jungehulsing, G J

    2016-01-01

    It has been proposed that cortical structural plasticity plays a crucial role in the emergence and maintenance of chronic pain. Various distinct pain syndromes have accordingly been linked to specific patterns of decreases in regional gray matter volume (GMV). However, it is not known whether central poststroke pain (CPSP) is also associated with cortical structural plasticity. To determine this, we employed T1-weighted magnetic resonance imaging at 3 T and voxel-based morphometry in 45 patients suffering from chronic subcortical sensory stroke with (n = 23) and without CPSP (n = 22), and healthy matched controls (n = 31). CPSP patients showed decreases in GMV in comparison to healthy controls, involving secondary somatosensory cortex (S2), anterior as well as posterior insular cortex, ventrolateral prefrontal and orbitofrontal cortex, temporal cortex, and nucleus accumbens. Comparing CPSP patients to nonpain patients revealed a similar but more restricted pattern of atrophy comprising S2, ventrolateral prefrontal and temporal cortex. Additionally, GMV in the ventromedial prefrontal cortex negatively correlated to pain intensity ratings. This shows for the first time that CPSP is accompanied by a unique pattern of widespread structural plasticity, which involves the sensory-discriminative areas of insular/somatosensory cortex, but also expands into prefrontal cortex and ventral striatum, where emotional aspects of pain are processed.

  7. Cortical thickness abnormalities associated with dyslexia, independent of remediation status.

    Science.gov (United States)

    Ma, Yizhou; Koyama, Maki S; Milham, Michael P; Castellanos, F Xavier; Quinn, Brian T; Pardoe, Heath; Wang, Xiuyuan; Kuzniecky, Ruben; Devinsky, Orrin; Thesen, Thomas; Blackmon, Karen

    2015-01-01

    Abnormalities in cortical structure are commonly observed in children with dyslexia in key regions of the "reading network." Whether alteration in cortical features reflects pathology inherent to dyslexia or environmental influence (e.g., impoverished reading experience) remains unclear. To address this question, we compared MRI-derived metrics of cortical thickness (CT), surface area (SA), gray matter volume (GMV), and their lateralization across three different groups of children with a historical diagnosis of dyslexia, who varied in current reading level. We compared three dyslexia subgroups with: (1) persistent reading and spelling impairment; (2) remediated reading impairment (normal reading scores), and (3) remediated reading and spelling impairments (normal reading and spelling scores); and a control group of (4) typically developing children. All groups were matched for age, gender, handedness, and IQ. We hypothesized that the dyslexia group would show cortical abnormalities in regions of the reading network relative to controls, irrespective of remediation status. Such a finding would support that cortical abnormalities are inherent to dyslexia and are not a consequence of abnormal reading experience. Results revealed increased CT of the left fusiform gyrus in the dyslexia group relative to controls. Similarly, the dyslexia group showed CT increase of the right superior temporal gyrus, extending into the planum temporale, which resulted in a rightward CT asymmetry on lateralization indices. There were no group differences in SA, GMV, or their lateralization. These findings held true regardless of remediation status. Each reading level group showed the same "double hit" of atypically increased left fusiform CT and rightward superior temporal CT asymmetry. Thus, findings provide evidence that a developmental history of dyslexia is associated with CT abnormalities, independent of remediation status.

  8. Cortical thickness abnormalities associated with dyslexia, independent of remediation status

    Directory of Open Access Journals (Sweden)

    Yizhou Ma

    2015-01-01

    Full Text Available Abnormalities in cortical structure are commonly observed in children with dyslexia in key regions of the “reading network.” Whether alteration in cortical features reflects pathology inherent to dyslexia or environmental influence (e.g., impoverished reading experience remains unclear. To address this question, we compared MRI-derived metrics of cortical thickness (CT, surface area (SA, gray matter volume (GMV, and their lateralization across three different groups of children with a historical diagnosis of dyslexia, who varied in current reading level. We compared three dyslexia subgroups with: (1 persistent reading and spelling impairment; (2 remediated reading impairment (normal reading scores, and (3 remediated reading and spelling impairments (normal reading and spelling scores; and a control group of (4 typically developing children. All groups were matched for age, gender, handedness, and IQ. We hypothesized that the dyslexia group would show cortical abnormalities in regions of the reading network relative to controls, irrespective of remediation status. Such a finding would support that cortical abnormalities are inherent to dyslexia and are not a consequence of abnormal reading experience. Results revealed increased CT of the left fusiform gyrus in the dyslexia group relative to controls. Similarly, the dyslexia group showed CT increase of the right superior temporal gyrus, extending into the planum temporale, which resulted in a rightward CT asymmetry on lateralization indices. There were no group differences in SA, GMV, or their lateralization. These findings held true regardless of remediation status. Each reading level group showed the same “double hit” of atypically increased left fusiform CT and rightward superior temporal CT asymmetry. Thus, findings provide evidence that a developmental history of dyslexia is associated with CT abnormalities, independent of remediation status.

  9. Cortical hypermetabolism in MCI subjects: a compensatory mechanism?

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    Ashraf, A.; Fan, Z.; Brooks, D.J.; Edison, P. [Imperial College London, Neurology Imaging Unit, Division of Brain Sciences, London (United Kingdom)

    2014-09-30

    Alzheimer's disease (AD) is associated with amyloid accumulation that takes place decades before symptoms appear. Cognitive impairment in AD is associated with reduced glucose metabolism. However, neuronal plasticity/compensatory mechanisms might come into play before the onset of dementia. The aim of this study was to determine whether there is evidence of cortical hypermetabolism as a compensatory mechanism before amyloid deposition takes place in subjects with amnestic mild cognitive impairment (aMCI). Nine AD subjects and ten aMCI subjects had both [{sup 11}C]PIB and [{sup 18}F]FDG PET scans with arterial input in order to quantify the amyloid deposition and glucose metabolism in vivo in comparison with healthy control subjects who underwent either [{sup 11}C]PIB or [{sup 18}F]FDG PET scans. The [{sup 11}C]PIB PET scans were quantified using [{sup 11}C]PIB target region to cerebellum uptake ratio images created by integrating the activity collected from 60 to 90 min, and regional cerebral glucose metabolism was quantified using spectral analysis. In MCI subjects, cortical hypermetabolism was observed in four amyloid-negative subjects and one amyloid-positive subject, while hypometabolism was seen in five other MCI subjects with high amyloid load. Subjects with hypermetabolism and low amyloid did not convert to AD during clinical follow-up for 18 months in contrast to four amyloid-positive hypometabolic subjects who did convert to AD. This preliminary study suggests that compensatory hypermetabolism can occur in aMCI subjects, particularly in those who are amyloid-negative. The increase in metabolic rate in different cortical regions with predominance in the occipital cortex may be a compensatory response to the neuronal damage occurring early in the disease process. It may also reflect recruitment of relatively minimally affected cortical regions to compensate for reduced function in the temporoparietal cortical association areas. (orig.)

  10. Differential effect of visual motion adaption upon visual cortical excitability.

    Science.gov (United States)

    Lubeck, Astrid J A; Van Ombergen, Angelique; Ahmad, Hena; Bos, Jelte E; Wuyts, Floris L; Bronstein, Adolfo M; Arshad, Qadeer

    2017-03-01

    The objectives of this study were 1) to probe the effects of visual motion adaptation on early visual and V5/MT cortical excitability and 2) to investigate whether changes in cortical excitability following visual motion adaptation are related to the degree of visual dependency, i.e., an overreliance on visual cues compared with vestibular or proprioceptive cues. Participants were exposed to a roll motion visual stimulus before, during, and after visual motion adaptation. At these stages, 20 transcranial magnetic stimulation (TMS) pulses at phosphene threshold values were applied over early visual and V5/MT cortical areas from which the probability of eliciting a phosphene was calculated. Before and after adaptation, participants aligned the subjective visual vertical in front of the roll motion stimulus as a marker of visual dependency. During adaptation, early visual cortex excitability decreased whereas V5/MT excitability increased. After adaptation, both early visual and V5/MT excitability were increased. The roll motion-induced tilt of the subjective visual vertical (visual dependence) was not influenced by visual motion adaptation and did not correlate with phosphene threshold or visual cortex excitability. We conclude that early visual and V5/MT cortical excitability is differentially affected by visual motion adaptation. Furthermore, excitability in the early or late visual cortex is not associated with an increase in visual reliance during spatial orientation. Our findings complement earlier studies that have probed visual cortical excitability following motion adaptation and highlight the differential role of the early visual cortex and V5/MT in visual motion processing.NEW & NOTEWORTHY We examined the influence of visual motion adaptation on visual cortex excitability and found a differential effect in V1/V2 compared with V5/MT. Changes in visual excitability following motion adaptation were not related to the degree of an individual's visual dependency.

  11. Cortical thickness abnormalities associated with dyslexia, independent of remediation status

    Science.gov (United States)

    Ma, Yizhou; Koyama, Maki S.; Milham, Michael P.; Castellanos, F. Xavier; Quinn, Brian T.; Pardoe, Heath; Wang, Xiuyuan; Kuzniecky, Ruben; Devinsky, Orrin; Thesen, Thomas; Blackmon, Karen

    2014-01-01

    Abnormalities in cortical structure are commonly observed in children with dyslexia in key regions of the “reading network.” Whether alteration in cortical features reflects pathology inherent to dyslexia or environmental influence (e.g., impoverished reading experience) remains unclear. To address this question, we compared MRI-derived metrics of cortical thickness (CT), surface area (SA), gray matter volume (GMV), and their lateralization across three different groups of children with a historical diagnosis of dyslexia, who varied in current reading level. We compared three dyslexia subgroups with: (1) persistent reading and spelling impairment; (2) remediated reading impairment (normal reading scores), and (3) remediated reading and spelling impairments (normal reading and spelling scores); and a control group of (4) typically developing children. All groups were matched for age, gender, handedness, and IQ. We hypothesized that the dyslexia group would show cortical abnormalities in regions of the reading network relative to controls, irrespective of remediation status. Such a finding would support that cortical abnormalities are inherent to dyslexia and are not a consequence of abnormal reading experience. Results revealed increased CT of the left fusiform gyrus in the dyslexia group relative to controls. Similarly, the dyslexia group showed CT increase of the right superior temporal gyrus, extending into the planum temporale, which resulted in a rightward CT asymmetry on lateralization indices. There were no group differences in SA, GMV, or their lateralization. These findings held true regardless of remediation status. Each reading level group showed the same “double hit” of atypically increased left fusiform CT and rightward superior temporal CT asymmetry. Thus, findings provide evidence that a developmental history of dyslexia is associated with CT abnormalities, independent of remediation status. PMID:25610779

  12. Adolescent brain maturation and cortical folding: evidence for reductions in gyrification.

    Directory of Open Access Journals (Sweden)

    Daniel Klein