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  1. Perirhinal Cortex Lesions Produce Retrograde Amnesia for Spatial Information in Rats: Consolidation or Retrieval?

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    Ramos, Juan M. J.

    2008-01-01

    Several lines of evidence in humans and experimental animals suggest that the hippocampus is critical for the formation and retrieval of spatial memory. However, although the hippocampus is reciprocally connected to adjacent cortices within the medial temporal lobe and they, in turn, are connected to the neocortex, little is known regarding the…

  2. Spatial Attention Changes Excitability of Human Visual Cortex to Direct Stimulation

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    Bestmann, Sven; Ruff, Christian C; Blakemore, Colin; Driver, Jon; Thilo, Kai V.

    2007-01-01

    Summary Conscious perception depends not only on sensory input, but also on attention [1, 2]. Recent studies in monkeys [3–6] and humans [7–12] suggest that influences of spatial attention on visual awareness may reflect top-down influences on excitability of visual cortex. Here we tested this specifically, by providing direct input into human visual cortex via cortical transcranial magnetic stimulation (TMS) to produce illusory visual percepts, called phosphenes. We found that a lower TMS in...

  3. Experience-dependent spatial expectations in mouse visual cortex

    DEFF Research Database (Denmark)

    Fiser, Aris; Mahringer, David; Oyibo, Hassana K.

    2016-01-01

    In generative models of brain function, internal representations are used to generate predictions of sensory input, yet little is known about how internal models influence sensory processing. Here we show that, with experience in a virtual environment, the activity of neurons in layer 2/3 of mouse...... primary visual cortex (V1) becomes increasingly informative of spatial location. We found that a subset of V1 neurons exhibited responses that were predictive of the upcoming visual stimulus in a spatially dependent manner and that the omission of an expected stimulus drove strong responses in V1....... Stimulus-predictive responses also emerged in V1-projecting anterior cingulate cortex axons, suggesting that anterior cingulate cortex serves as a source of predictions of visual input to V1. These findings are consistent with the hypothesis that visual cortex forms an internal representation of the visual...

  4. Encoding and storage of spatial information in the retrosplenial cortex.

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    Czajkowski, Rafał; Jayaprakash, Balaji; Wiltgen, Brian; Rogerson, Thomas; Guzman-Karlsson, Mikael C; Barth, Alison L; Trachtenberg, Joshua T; Silva, Alcino J

    2014-06-10

    The retrosplenial cortex (RSC) is part of a network of interconnected cortical, hippocampal, and thalamic structures harboring spatially modulated neurons. The RSC contains head direction cells and connects to the parahippocampal region and anterior thalamus. Manipulations of the RSC can affect spatial and contextual tasks. A considerable amount of evidence implicates the role of the RSC in spatial navigation, but it is unclear whether this structure actually encodes or stores spatial information. We used a transgenic mouse in which the expression of green fluorescent protein was under the control of the immediate early gene c-fos promoter as well as time-lapse two-photon in vivo imaging to monitor neuronal activation triggered by spatial learning in the Morris water maze. We uncovered a repetitive pattern of cell activation in the RSC consistent with the hypothesis that during spatial learning an experience-dependent memory trace is formed in this structure. In support of this hypothesis, we also report three other observations. First, temporary RSC inactivation disrupts performance in a spatial learning task. Second, we show that overexpressing the transcription factor CREB in the RSC with a viral vector, a manipulation known to enhance memory consolidation in other circuits, results in spatial memory enhancements. Third, silencing the viral CREB-expressing neurons with the allatostatin system occludes the spatial memory enhancement. Taken together, these results indicate that the retrosplenial cortex engages in the formation and storage of memory traces for spatial information.

  5. Spatial Working Memory Effects in Early Visual Cortex

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    Munneke, Jaap; Heslenfeld, Dirk J.; Theeuwes, Jan

    2010-01-01

    The present study investigated how spatial working memory recruits early visual cortex. Participants were required to maintain a location in working memory while changes in blood oxygen level dependent (BOLD) signals were measured during the retention interval in which no visual stimulation was present. We show working memory effects during the…

  6. Chronic infusions of GABA into the medial prefrontal cortex induce spatial alternation deficits in aged rats.

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    Meneses, S; Galicia, O; Brailowsky, S

    1993-10-21

    It has been proposed that functions associated with the prefrontal cortex could change as a consequence of aging. Previous experiments in young rats have demonstrated that anatomical lesions or chronic GABA infusions into this area produce deficits in spatial delayed alternation tasks. The present study examines the effect of chronic (7 days) GABA or saline infusion into the prefrontal cortex on the performance of delayed alternation task in old rats (24 months). The results suggested that aged rats needed more sessions to acquire the delayed alternation task. GABA infusions into the prefrontal cortex produced deficits in spatial alternation tasks similar to those previously observed in young rats. Performance rapidly recovered after the infusion period. Histological analysis showed similar lesion size in both groups. The results suggest that aged prefrontal cortex and/or related areas participating in the acquisition of the delayed alternation task are more sensitive to aging processes. Furthermore, the prefrontal cortex is important for the retention of a previously learned spatial delayed alternation task. The structures involved in functional recovery from these deficits appear to be fully functional in aged rats.

  7. Spatial diversity of spontaneous activity in the cortex

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    Andrew Yong-Yi Tan

    2015-09-01

    Full Text Available The neocortex is a layered sheet across which a basic organization is thought to widely apply. The variety of spontaneous activity patterns is similar throughout the cortex, consistent with the notion of a basic cortical organization. However, the basic organization is only an outline which needs adjustments and additions to account for the structural and functional diversity across cortical layers and areas. Such diversity suggests that spontaneous activity is spatially diverse in any particular behavioral state. Accordingly, this review summarizes the laminar and areal diversity in cortical activity during fixation and slow oscillations, and the effects of attention, anesthesia and plasticity on the cortical distribution of spontaneous activity. Among questions that remain open, characterizing the spatial diversity in spontaneous membrane potential may help elucidate how differences in circuitry among cortical regions supports their varied functions. More work is also needed to understand whether cortical spontaneous activity not only reflects cortical circuitry, but also contributes to determining the outcome of plasticity, so that it is itself a factor shaping the functional diversity of the cortex.

  8. Spatial encoding and underlying circuitry in scene-selective cortex.

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    Nasr, Shahin; Devaney, Kathryn J; Tootell, Roger B H

    2013-12-01

    Three cortical areas (Retro-Splenial Cortex (RSC), Transverse Occipital Sulcus (TOS) and Parahippocampal Place Area (PPA)) respond selectively to scenes. However, their wider role in spatial encoding and their functional connectivity remain unclear. Using fMRI, first we tested the responses of these areas during spatial comparison tasks using dot targets on white noise. Activity increased during task performance in both RSC and TOS, but not in PPA. However, the amplitude of task-driven activity and behavioral measures of task demand were correlated only in RSC. A control experiment showed that none of these areas were activated during a comparable shape comparison task. Secondly, we analyzed functional connectivity of these areas during the resting state. Results revealed a significant connection between RSC and frontal association areas (known to be involved in perceptual decision-making). In contrast, TOS showed functional connections dorsally with the Inferior Parietal Sulcus, and ventrally with the Lateral Occipital Complex--but not with RSC and/or frontal association areas. Moreover, RSC and TOS showed differentiable functional connections with the anterior-medial and posterior-lateral parts of PPA, respectively. These results suggest two parallel pathways for spatial encoding, including RSC and TOS respectively. Only the RSC network was involved in active spatial comparisons.

  9. Chronic infusions of GABA into the medial frontal cortex of the rat induce a reversible delayed spatial alternation deficit.

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    Di Scala, G; Meneses, S; Brailowsky, S

    1990-10-30

    The effects of bilateral infusions of GABA into the medial frontal cortex of the rat were studied in a delayed spatial alternation task. It was found that GABA (500 mM, 1 microliter/h during 7 days) impaired the performance of the rats in the previously learned task. Upon interruption of the treatment, the animals rapidly recovered normal performance scores. The results show that GABA infusions produce functional deficits similar to those produced by lesions of the frontal cortex. Moreover, the deficits are reversible upon interruption of the treatment. This technique may therefore be a useful tool for studying frontal lobe functions and the involvement of GABAergic mechanisms in cognitive processes.

  10. Spatial organization of astrocytes in ferret visual cortex

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    López‐Hidalgo, Mónica; Hoover, Walter B.

    2016-01-01

    ABSTRACT Astrocytes form an intricate partnership with neural circuits to influence numerous cellular and synaptic processes. One prominent organizational feature of astrocytes is the “tiling” of the brain with non‐overlapping territories. There are some documented species and brain region–specific astrocyte specializations, but the extent of astrocyte diversity and circuit specificity are still unknown. We quantitatively defined the rules that govern the spatial arrangement of astrocyte somata and territory overlap in ferret visual cortex using a combination of in vivo two‐photon imaging, morphological reconstruction, immunostaining, and model simulations. We found that ferret astrocytes share, on average, half of their territory with other astrocytes. However, a specific class of astrocytes, abundant in thalamo‐recipient cortical layers (“kissing” astrocytes), overlap markedly less. Together, these results demonstrate novel features of astrocyte organization indicating that different classes of astrocytes are arranged in a circuit‐specific manner and that tiling does not apply universally across brain regions and species. J. Comp. Neurol. 524:3561–3576, 2016. © 2016 The Authors The Journal of Comparative Neurology Published by Wiley Periodicals, Inc. PMID:27072916

  11. [Spatial Cognition and Episodic Memory Formation in the Limbic Cortex].

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    Kobayashi, Yasushi

    2017-04-01

    The limbic lobe defined by Broca is a cortical region with highly diverse structure and functions, and comprises the paleo-, archi-, and neocortices as well as their transitional zones. In the limbic lobe, Brodmann designated areas 27, 28, 34, 35, and 36 adjacent to the hippocampus, and areas 23, 24, 25, 26, 29, 30, 31, 32, and 33 around the corpus callosum. In the current literature, areas 27 and 28 correspond to the presubiculum and entorhinal cortex, respectively. Area 34 represents the cortico-medial part of the amygdaloid complex. Areas 35 and 36 roughly cover the perirhinal and parahippocampal cortices. Areas 24, 25, 32, and 33 belong to the anterior cingulate gyrus, while areas 23, 26, 29, 30, and 31 to the posterior cingulate gyrus. Areas 25, 32, and the anteroinferior portion of area 24 are deeply involved in emotional responses, particularly in their autonomic functions, through reciprocal connections with the amygdaloid complex, anterior thalamus and projections to the brainstem and spinal visceral centers. Areas 29 and 30 have dense reciprocal connections with areas 23 and 31, the dorsolateral prefrontal areas, and the regions related to the hippocampus. They play pivotal roles in mediating spatial cognition, working memory processing, and episodic memory formation.

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

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    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.

  13. Involvement of the superior temporal cortex and the occipital cortex in spatial hearing: evidence from repetitive transcranial magnetic stimulation.

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    Lewald, Jörg; Meister, Ingo G; Weidemann, Jürgen; Töpper, Rudolf

    2004-06-01

    The processing of auditory spatial information in cortical areas of the human brain outside of the primary auditory cortex remains poorly understood. Here we investigated the role of the superior temporal gyrus (STG) and the occipital cortex (OC) in spatial hearing using repetitive transcranial magnetic stimulation (rTMS). The right STG is known to be of crucial importance for visual spatial awareness, and has been suggested to be involved in auditory spatial perception. We found that rTMS of the right STG induced a systematic error in the perception of interaural time differences (a primary cue for sound localization in the azimuthal plane). This is in accordance with the recent view, based on both neurophysiological data obtained in monkeys and human neuroimaging studies, that information on sound location is processed within a dorsolateral "where" stream including the caudal STG. A similar, but opposite, auditory shift was obtained after rTMS of secondary visual areas of the right OC. Processing of auditory information in the OC has previously been shown to exist only in blind persons. Thus, the latter finding provides the first evidence of an involvement of the visual cortex in spatial hearing in sighted human subjects, and suggests a close interconnection of the neural representation of auditory and visual space. Because rTMS induced systematic shifts in auditory lateralization, but not a general deterioration, we propose that rTMS of STG or OC specifically affected neuronal circuits transforming auditory spatial coordinates in order to maintain alignment with vision.

  14. A Computational Model for Spatial Navigation Based on Reference Frames in the Hippocampus, Retrosplenial Cortex, and Posterior Parietal Cortex

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    Oess, Timo; Krichmar, Jeffrey L.; Röhrbein, Florian

    2017-01-01

    Behavioral studies for humans, monkeys, and rats have shown that, while traversing an environment, these mammals tend to use different frames of reference and frequently switch between them. These frames represent allocentric, egocentric, or route-centric views of the environment. However, combinations of either of them are often deployed. Neurophysiological studies on rats have indicated that the hippocampus, the retrosplenial cortex, and the posterior parietal cortex contribute to the formation of these frames and mediate the transformation between those. In this paper, we construct a computational model of the posterior parietal cortex and the retrosplenial cortex for spatial navigation. We demonstrate how the transformation of reference frames could be realized in the brain and suggest how different brain areas might use these reference frames to form navigational strategies and predict under what conditions an animal might use a specific type of reference frame. Our simulated navigation experiments demonstrate that the model’s results closely resemble behavioral findings in humans and rats. These results suggest that navigation strategies may depend on the animal’s reliance in a particular reference frame and shows how low confidence in a reference frame can lead to fluid adaptation and deployment of alternative navigation strategies. Because of its flexibility, our biologically inspired navigation system may be applied to autonomous robots. PMID:28223931

  15. Modeling the motor cortex: Optimality, recurrent neural networks, and spatial dynamics.

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    Tanaka, Hirokazu

    2016-03-01

    Specialization of motor function in the frontal lobe was first discovered in the seminal experiments by Fritsch and Hitzig and subsequently by Ferrier in the 19th century. It is, however, ironical that the functional and computational role of the motor cortex still remains unresolved. A computational understanding of the motor cortex equals to understanding what movement variables the motor neurons represent (movement representation problem) and how such movement variables are computed through the interaction with anatomically connected areas (neural computation problem). Electrophysiological experiments in the 20th century demonstrated that the neural activities in motor cortex correlated with a number of motor-related and cognitive variables, thereby igniting the controversy over movement representations in motor cortex. Despite substantial experimental efforts, the overwhelming complexity found in neural activities has impeded our understanding of how movements are represented in the motor cortex. Recent progresses in computational modeling have rekindled this controversy in the 21st century. Here, I review the recent developments in computational models of the motor cortex, with a focus on optimality models, recurrent neural network models and spatial dynamics models. Although individual models provide consistent pictures within their domains, our current understanding about functions of the motor cortex is still fragmented.

  16. Human Topological Task Adapted for Rats: Spatial Information Processes of the Parietal Cortex

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    Goodrich-Hunsaker, Naomi J.; Howard, Brian P.; Hunsaker, Michael R.; Kesner, Raymond P.

    2008-01-01

    Human research has shown that lesions of the parietal cortex disrupt spatial information processing, specifically topological information. Similar findings have been found in nonhumans. It has been difficult to determine homologies between human and non-human mnemonic mechanisms for spatial information processing because methodologies and neuropathology differ. The first objective of the present study was to adapt a previously established human task for rats. The second objective was to bette...

  17. Human Topological Task Adapted for Rats: Spatial Information Processes of the Parietal Cortex

    OpenAIRE

    Goodrich-Hunsaker, Naomi J.; Howard, Brian P.; Hunsaker, Michael R.; Kesner, Raymond P.

    2008-01-01

    Human research has shown that lesions of the parietal cortex disrupt spatial information processing, specifically topological information. Similar findings have been found in nonhumans. It has been difficult to determine homologies between human and non-human mnemonic mechanisms for spatial information processing because methodologies and neuropathology differ. The first objective of the present study was to adapt a previously established human task for rats. The second objective was to bette...

  18. The parietal cortex in sensemaking: the dissociation of multiple types of spatial information.

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    Sun, Yanlong; Wang, Hongbin

    2013-01-01

    According to the data-frame theory, sensemaking is a macrocognitive process in which people try to make sense of or explain their observations by processing a number of explanatory structures called frames until the observations and frames become congruent. During the sensemaking process, the parietal cortex has been implicated in various cognitive tasks for the functions related to spatial and temporal information processing, mathematical thinking, and spatial attention. In particular, the parietal cortex plays important roles by extracting multiple representations of magnitudes at the early stages of perceptual analysis. By a series of neural network simulations, we demonstrate that the dissociation of different types of spatial information can start early with a rather similar structure (i.e., sensitivity on a common metric), but accurate representations require specific goal-directed top-down controls due to the interference in selective attention. Our results suggest that the roles of the parietal cortex rely on the hierarchical organization of multiple spatial representations and their interactions. The dissociation and interference between different types of spatial information are essentially the result of the competition at different levels of abstraction.

  19. Independent effects of motivation and spatial attention in the human visual cortex.

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    Bayer, Mareike; Rossi, Valentina; Vanlessen, Naomi; Grass, Annika; Schacht, Annekathrin; Pourtois, Gilles

    2016-12-28

    Motivation and attention constitute major determinants of human perception and action. Nonetheless, it remains a matter of debate whether motivation effects on the visual cortex depend on the spatial attention system, or rely on independent pathways. This study investigated the impact of motivation and spatial attention on the activity of the human primary and extrastriate visual cortex by employing a factorial manipulation of the two factors in a cued pattern discrimination task. During stimulus presentation, we recorded event-related potentials and pupillary responses. Motivational relevance increased the amplitudes of the C1 component at ∼70 ms after stimulus onset. This modulation occurred independently of spatial attention effects, which were evident at the P1 level. Furthermore, motivation and spatial attention had independent effects on preparatory activation as measured by the contingent negative variation; and pupil data showed increased activation in response to incentive targets. Taken together, these findings suggest independent pathways for the influence of motivation and spatial attention on the activity of the human visual cortex.

  20. The Parietal Cortex in Sensemaking: The Dissociation of Multiple Types of Spatial Information

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    Yanlong Sun

    2013-01-01

    Full Text Available According to the data-frame theory, sensemaking is a macrocognitive process in which people try to make sense of or explain their observations by processing a number of explanatory structures called frames until the observations and frames become congruent. During the sensemaking process, the parietal cortex has been implicated in various cognitive tasks for the functions related to spatial and temporal information processing, mathematical thinking, and spatial attention. In particular, the parietal cortex plays important roles by extracting multiple representations of magnitudes at the early stages of perceptual analysis. By a series of neural network simulations, we demonstrate that the dissociation of different types of spatial information can start early with a rather similar structure (i.e., sensitivity on a common metric, but accurate representations require specific goal-directed top-down controls due to the interference in selective attention. Our results suggest that the roles of the parietal cortex rely on the hierarchical organization of multiple spatial representations and their interactions. The dissociation and interference between different types of spatial information are essentially the result of the competition at different levels of abstraction.

  1. Prenatal Stress Produces Persistence of Remote Memory and Disrupts Functional Connectivity in the Hippocampal-Prefrontal Cortex Axis.

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    Negrón-Oyarzo, Ignacio; Neira, David; Espinosa, Nelson; Fuentealba, Pablo; Aboitiz, Francisco

    2015-09-01

    Prenatal stress is a risk factor for the development of neuropsychiatric disorders, many of which are commonly characterized by an increased persistence of aversive remote memory. Here, we addressed the effect of prenatal stress on both memory consolidation and functional connectivity in the hippocampal-prefrontal cortex axis, a dynamical interplay that is critical for mnemonic processing. Pregnant mice of the C57BL6 strain were subjected to restraint stressed during the last week of pregnancy, and male offspring were behaviorally tested at adulthood for recent and remote spatial memory performance in the Barnes Maze test under an aversive context. Prenatal stress did not affect the acquisition or recall of recent memory. In contrast, it produced the persistence of remote spatial memory. Memory persistence was not associated with alterations in major network rhythms, such as hippocampal sharp-wave ripples (SWRs) or neocortical spindles. Instead, it was associated with a large decrease in the basal discharge activity of identified principal neurons in the medial prefrontal cortex (mPFC) as measured in urethane anesthetized mice. Furthermore, functional connectivity was disrupted, as the temporal coupling between neuronal discharge in the mPFC and hippocampal SWRs was decreased by prenatal stress. These results could be relevant to understand the biological basis of the persistence of aversive remote memories in stress-related disorders.

  2. Dynamic changes in phase-amplitude coupling facilitate spatial attention control in fronto-parietal cortex.

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    Sara M Szczepanski

    2014-08-01

    Full Text Available Attention is a core cognitive mechanism that allows the brain to allocate limited resources depending on current task demands. A number of frontal and posterior parietal cortical areas, referred to collectively as the fronto-parietal attentional control network, are engaged during attentional allocation in both humans and non-human primates. Numerous studies have examined this network in the human brain using various neuroimaging and scalp electrophysiological techniques. However, little is known about how these frontal and parietal areas interact dynamically to produce behavior on a fine temporal (sub-second and spatial (sub-centimeter scale. We addressed how human fronto-parietal regions control visuospatial attention on a fine spatiotemporal scale by recording electrocorticography (ECoG signals measured directly from subdural electrode arrays that were implanted in patients undergoing intracranial monitoring for localization of epileptic foci. Subjects (n = 8 performed a spatial-cuing task, in which they allocated visuospatial attention to either the right or left visual field and detected the appearance of a target. We found increases in high gamma (HG power (70-250 Hz time-locked to trial onset that remained elevated throughout the attentional allocation period over frontal, parietal, and visual areas. These HG power increases were modulated by the phase of the ongoing delta/theta (2-5 Hz oscillation during attentional allocation. Critically, we found that the strength of this delta/theta phase-HG amplitude coupling predicted reaction times to detected targets on a trial-by-trial basis. These results highlight the role of delta/theta phase-HG amplitude coupling as a mechanism for sub-second facilitation and coordination within human fronto-parietal cortex that is guided by momentary attentional demands.

  3. Spatial phase sensitivity of complex cells in primary visual cortex depends on stimulus contrast.

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    Meffin, H; Hietanen, M A; Cloherty, S L; Ibbotson, M R

    2015-12-01

    Neurons in primary visual cortex are classified as simple, which are phase sensitive, or complex, which are significantly less phase sensitive. Previously, we have used drifting gratings to show that the phase sensitivity of complex cells increases at low contrast and after contrast adaptation while that of simple cells remains the same at all contrasts (Cloherty SL, Ibbotson MR. J Neurophysiol 113: 434-444, 2015; Crowder NA, van Kleef J, Dreher B, Ibbotson MR. J Neurophysiol 98: 1155-1166, 2007; van Kleef JP, Cloherty SL, Ibbotson MR. J Physiol 588: 3457-3470, 2010). However, drifting gratings confound the influence of spatial and temporal summation, so here we have stimulated complex cells with gratings that are spatially stationary but continuously reverse the polarity of the contrast over time (contrast-reversing gratings). By varying the spatial phase and contrast of the gratings we aimed to establish whether the contrast-dependent phase sensitivity of complex cells results from changes in spatial or temporal processing or both. We found that most of the increase in phase sensitivity at low contrasts could be attributed to changes in the spatial phase sensitivities of complex cells. However, at low contrasts the complex cells did not develop the spatiotemporal response characteristics of simple cells, in which paired response peaks occur 180° out of phase in time and space. Complex cells that increased their spatial phase sensitivity at low contrasts were significantly overrepresented in the supragranular layers of cortex. We conclude that complex cells in supragranular layers of cat cortex have dynamic spatial summation properties and that the mechanisms underlying complex cell receptive fields differ between cortical layers.

  4. Top-down spatial categorization signal from prefrontal to posterior parietal cortex in the primate

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    Hugo eMerchant

    2011-08-01

    Full Text Available In the present study we characterized the strength and time course of category-selective responses in prefrontal cortex and area 7a of the posterior parietal cortex during a match-to-sample spatial categorization task. A monkey was trained to categorize whether the height of a horizontal sample bar, presented in rectangular frame at one of three vertical locations, was "high" or "low", depending on whether its position was above or below the frame’s midline. After the display of this sample bar, and after a delay, choice bars were sequentially flashed in two locations: at the top and at the bottom of the frame (‘choice’ epoch. If the monkey timed its response to the display of the choice bar that matched the sample bar, he was rewarded. We found that cells in prefrontal cortex discriminated category early after the initial sample bar was shown, and continued to differentiate up from down trials throughout the delay and choice periods. In contrast, parietal cells did not differentiate category until the choice period. Therefore, our results support the notion of a top-down categorical signal that originates in prefrontal cortex and that is only represented in parietal cortex when it is necessary to express the categorical decision through a movement.

  5. Representation of nonspatial and spatial information in the lateral entorhinal cortex

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    Sachin S Deshmukh

    2011-10-01

    Full Text Available Some theories of memory propose that the hippocampus integrates the individual items and events of experience within a contextual or spatial framework. The hippocampus receives cortical input from two major pathways: the medial entorhinal cortex (MEC and the lateral entorhinal cortex (LEC. During exploration in an open field, the firing fields of MEC grid cells form a periodically repeating, triangular array. In contrast, LEC neurons show little spatial selectivity, and it has been proposed that the LEC may provide nonspatial input to the hippocampus. Here, we recorded MEC and LEC neurons while rats explored an open field that contained discrete objects. LEC cells fired selectively at locations relative to the objects, whereas MEC cells were weakly influenced by the objects. These results provide the first direct demonstration of a double dissociation between LEC and MEC inputs to the hippocampus under conditions of exploration typically used to study hippocampal place cells.

  6. Cues, context, and long-term memory: the role of the retrosplenial cortex in spatial cognition

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    Adam M P Miller

    2014-08-01

    Full Text Available Spatial navigation requires representations of landmarks and other navigation cues. The retrosplenial cortex (RSC is anatomically positioned between limbic areas important for memory formation, such as the hippocampus and the anterior thalamus, and cortical regions along the dorsal stream known to contribute importantly to long-term spatial representation, such as the posterior parietal cortex. Damage to the RSC severely impairs allocentric representations of the environment, including the ability to derive navigational information from landmarks. The specific deficits seen in tests of human and rodent navigation suggest that the RSC supports allocentric representation by processing the stable features of the environment and the spatial relationships among them. In addition to spatial cognition, the RSC plays a key role in contextual and episodic memory. The RSC also contributes importantly to the acquisition and consolidation of long-term spatial and contextual memory through its interactions with the hippocampus. Within this framework, the RSC plays a dual role as part of the feedforward network providing sensory and mnemonic input to the hippocampus and as a target of the hippocampal-dependent systems consolidation of long-term memory.

  7. Spatially global representations in human primary visual cortex during working memory maintenance.

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    Ester, Edward F; Serences, John T; Awh, Edward

    2009-12-02

    Recent studies suggest that visual features are stored in working memory (WM) via sensory recruitment or sustained stimulus-specific patterns of activity in cortical regions that encode memoranda. One important question concerns the spatial extent of sensory recruitment. One possibility is that sensory recruitment is restricted to neurons that are retinotopically mapped to the positions occupied by the remembered items. Alternatively, specific feature values could be represented via a spatially global recruitment of neurons that encode the remembered feature, regardless of the retinotopic position of the remembered stimulus. Here, we evaluated these alternatives by requiring subjects to remember the orientation of a grating presented in the left or right visual field. Functional magnetic resonance imaging and multivoxel pattern analysis were then used to examine feature-specific activations in early visual regions during memory maintenance. Activation patterns that discriminated the remembered feature were found in regions of contralateral visual cortex that corresponded to the retinotopic position of the remembered item, as well as in ipsilateral regions that were not retinotopically mapped to the position of the stored stimulus. These results suggest that visual details are held in WM through a spatially global recruitment of early sensory cortex. This spatially global recruitment may enhance memory precision by facilitating robust population coding of the stored information.

  8. Object and spatial mnemonic interference differentially engage lateral and medial entorhinal cortex in humans.

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    Reagh, Zachariah M; Yassa, Michael A

    2014-10-07

    Recent models of episodic memory propose a division of labor among medial temporal lobe cortices comprising the parahippocampal gyrus. Specifically, perirhinal and lateral entorhinal cortices are thought to comprise an object/item information pathway, whereas parahippocampal and medial entorhinal cortices are thought to comprise a spatial/contextual information pathway. Although several studies in human subjects have demonstrated a perirhinal/parahippocampal division, such a division among subregions of the human entorhinal cortex has been elusive. Other recent work has implicated pattern separation computations in the dentate gyrus and CA3 subregions of the hippocampus as a mechanism supporting the resolution of mnemonic interference. However, the nature of contributions of medial temporal lobe cortices to downstream hippocampal computations is largely unknown. We used high-resolution fMRI during a task selectively taxing mnemonic discrimination of object identity or spatial location, designed to differentially engage the two information pathways in the medial temporal lobes. Consistent with animal models, we demonstrate novel evidence for a domain-selective dissociation between lateral and medial entorhinal cortex in humans, and between perirhinal and parahippocampal cortex as a function of information content. Conversely, hippocampal dentate gyrus/CA3 demonstrated signals consistent with resolution of mnemonic interference across domains. These results provide insight into the information processing capacities and hierarchical interference resolution throughout the human medial temporal lobe.

  9. Preparatory activity in visual cortex indexes distractor suppression during covert spatial orienting.

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    Serences, John T; Yantis, Steven; Culberson, Andrew; Awh, Edward

    2004-12-01

    The deployment of spatial attention induces retinotopically specific increases in neural activity that occur even before a target stimulus is presented. Although this preparatory activity is thought to prime the attended regions, thereby improving perception and recognition, it is not yet clear whether this activity is a manifestation of signal enhancement at the attended locations or suppression of interference from distracting stimuli (or both). We investigated the functional role of these preparatory shifts by isolating a distractor suppression component of selection. Behavioral data have shown that manipulating the probability that visual distractors will appear modulates distractor suppression without concurrent changes in signal enhancement. In 2 experiments, functional magnetic resonance imaging revealed increased cue-evoked activity in retinotopically specific regions of visual cortex when increased distractor suppression was elicited by a high probability of distractors. This finding directly links cue-evoked preparatory activity in visual cortex with a distractor suppression component of visual selective attention.

  10. Effect of Contrast on Visual Spatial Summation in Different Cell Categories in Cat Primary Visual Cortex.

    Directory of Open Access Journals (Sweden)

    Ke Chen

    Full Text Available Multiple cell classes have been found in the primary visual cortex, but the relationship between cell types and spatial summation has seldom been studied. Parvalbumin-expressing inhibitory interneurons can be distinguished from pyramidal neurons based on their briefer action potential durations. In this study, we classified V1 cells into fast-spiking units (FSUs and regular-spiking units (RSUs and then examined spatial summation at high and low contrast. Our results revealed that the excitatory classical receptive field and the suppressive non-classical receptive field expanded at low contrast for both FSUs and RSUs, but the expansion was more marked for the RSUs than for the FSUs. For most V1 neurons, surround suppression varied as the contrast changed from high to low. However, FSUs exhibited no significant difference in the strength of suppression between high and low contrast, although the overall suppression decreased significantly at low contrast for the RSUs. Our results suggest that the modulation of spatial summation by stimulus contrast differs across populations of neurons in the cat primary visual cortex.

  11. Visual spatial attention has opposite effects on bidirectional plasticity in the human motor cortex.

    Science.gov (United States)

    Kamke, Marc R; Ryan, Alexander E; Sale, Martin V; Campbell, Megan E J; Riek, Stephan; Carroll, Timothy J; Mattingley, Jason B

    2014-01-22

    Long-term potentiation (LTP) and long-term depression (LTD) are key mechanisms of synaptic plasticity that are thought to act in concert to shape neural connections. Here we investigated the influence of visual spatial attention on LTP-like and LTD-like plasticity in the human motor cortex. Plasticity was induced using paired associative stimulation (PAS), which involves repeated pairing of peripheral nerve stimulation and transcranial magnetic stimulation to alter functional responses in the thumb area of the primary motor cortex. PAS-induced changes in cortical excitability were assessed using motor-evoked potentials. During plasticity induction, participants directed their attention to one of two visual stimulus streams located adjacent to each hand. When participants attended to visual stimuli located near the left thumb, which was targeted by PAS, LTP-like increases in excitability were significantly enhanced, and LTD-like decreases in excitability reduced, relative to when they attended instead to stimuli located near the right thumb. These differential effects on (bidirectional) LTP-like and LTD-like plasticity suggest that voluntary visual attention can exert an important influence on the functional organization of the motor cortex. Specifically, attention acts to both enhance the strengthening and suppress the weakening of neural connections representing events that fall within the focus of attention.

  12. Spatial Representations in Local Field Potential Activity of Primate Anterior Intraparietal Cortex (AIP).

    Science.gov (United States)

    Lehmann, Sebastian J; Scherberger, Hansjörg

    2015-01-01

    The execution of reach-to-grasp movements in order to interact with our environment is an important subset of the human movement repertoire. To coordinate such goal-directed movements, information about the relative spatial position of target and effector (in this case the hand) has to be continuously integrated and processed. Recently, we reported the existence of spatial representations in spiking-activity of the cortical fronto-parietal grasp network (Lehmann & Scherberger 2013), and in particular in the anterior intraparietal cortex (AIP). To further investigate the nature of these spatial representations, we explored in two rhesus monkeys (Macaca mulatta) how different frequency bands of the local field potential (LFP) in AIP are modulated by grip type, target position, and gaze position, during the planning and execution of reach-to-grasp movements. We systematically varied grasp type, spatial target, and gaze position and found that both spatial and grasp information were encoded in a variety of frequency bands (1-13Hz, 13-30Hz, 30-60Hz, and 60-100Hz, respectively). Whereas the representation of grasp type strongly increased towards and during movement execution, spatial information was represented throughout the task. Both spatial and grasp type representations could be readily decoded from all frequency bands. The fact that grasp type and spatial (reach) information was found not only in spiking activity, but also in various LFP frequency bands of AIP, might significantly contribute to the development of LFP-based neural interfaces for the control of upper limb prostheses.

  13. Spatial Representations in Local Field Potential Activity of Primate Anterior Intraparietal Cortex (AIP.

    Directory of Open Access Journals (Sweden)

    Sebastian J Lehmann

    Full Text Available The execution of reach-to-grasp movements in order to interact with our environment is an important subset of the human movement repertoire. To coordinate such goal-directed movements, information about the relative spatial position of target and effector (in this case the hand has to be continuously integrated and processed. Recently, we reported the existence of spatial representations in spiking-activity of the cortical fronto-parietal grasp network (Lehmann & Scherberger 2013, and in particular in the anterior intraparietal cortex (AIP. To further investigate the nature of these spatial representations, we explored in two rhesus monkeys (Macaca mulatta how different frequency bands of the local field potential (LFP in AIP are modulated by grip type, target position, and gaze position, during the planning and execution of reach-to-grasp movements. We systematically varied grasp type, spatial target, and gaze position and found that both spatial and grasp information were encoded in a variety of frequency bands (1-13Hz, 13-30Hz, 30-60Hz, and 60-100Hz, respectively. Whereas the representation of grasp type strongly increased towards and during movement execution, spatial information was represented throughout the task. Both spatial and grasp type representations could be readily decoded from all frequency bands. The fact that grasp type and spatial (reach information was found not only in spiking activity, but also in various LFP frequency bands of AIP, might significantly contribute to the development of LFP-based neural interfaces for the control of upper limb prostheses.

  14. Deconstructing visual scenes in cortex: gradients of object and spatial layout information.

    Science.gov (United States)

    Harel, Assaf; Kravitz, Dwight J; Baker, Chris I

    2013-04-01

    Real-world visual scenes are complex cluttered, and heterogeneous stimuli engaging scene- and object-selective cortical regions including parahippocampal place area (PPA), retrosplenial complex (RSC), and lateral occipital complex (LOC). To understand the unique contribution of each region to distributed scene representations, we generated predictions based on a neuroanatomical framework adapted from monkey and tested them using minimal scenes in which we independently manipulated both spatial layout (open, closed, and gradient) and object content (furniture, e.g., bed, dresser). Commensurate with its strong connectivity with posterior parietal cortex, RSC evidenced strong spatial layout information but no object information, and its response was not even modulated by object presence. In contrast, LOC, which lies within the ventral visual pathway, contained strong object information but no background information. Finally, PPA, which is connected with both the dorsal and the ventral visual pathway, showed information about both objects and spatial backgrounds and was sensitive to the presence or absence of either. These results suggest that 1) LOC, PPA, and RSC have distinct representations, emphasizing different aspects of scenes, 2) the specific representations in each region are predictable from their patterns of connectivity, and 3) PPA combines both spatial layout and object information as predicted by connectivity.

  15. Dissociable Memory- and Response-Related Activity in Parietal Cortex during Auditory Spatial Working Memory

    Directory of Open Access Journals (Sweden)

    Claude Alain

    2010-12-01

    Full Text Available Attending and responding to sound location generates increased activity in parietal cortex which may index auditory spatial working memory and/or goal-directed action. Here, we used an n-back task (Experiment 1 and an adaptation paradigm (Experiment 2 to distinguish memory-related activity from that associated with goal-directed action. In Experiment 1, participants indicated, in separate blocks of trials, whether the incoming stimulus was presented at the same location as in the previous trial (1-back or two trials ago (2-back. Prior to a block of trials, participants were told to use their left or right index finger. Accuracy and reaction times were worse for the 2-back than for the 1-back condition. The analysis of fMRI data revealed greater sustained task-related activity in the inferior parietal lobule (IPL and superior frontal sulcus during 2-back than 1-back after accounting for response-related activity elicited by the targets. Target detection and response execution were also associated with enhanced activity in the IPL bilaterally, though the activation was anterior to that associated with sustained task-related activity. In Experiment 2, we used an event-related design in which participants listened (no response required to trials that comprised four sounds presented either at the same location or at four different locations. We found larger IPL activation for changes in sound location than for sounds presented at the same location. The IPL activation overlapped with that observed during auditory spatial working memory task. Together, these results provide converging evidence supporting the role of parietal cortex in auditory spatial working memory which can be dissociated from response selection and execution.

  16. Effect of excitotoxic lesions of rat medial prefrontal cortex on spatial memory.

    Science.gov (United States)

    Lacroix, Laurent; White, Ilsun; Feldon, Joram

    2002-06-15

    The involvement of medial prefrontal cortex (mPFC) in spatial learning was examined in two memory tasks using spatial components, the Morris water maze and the three-panel runway. Using the Morris water maze task, with an invisible platform, the effects of NMDA mPFC lesions were assessed in a procedure reflecting spatial learning and memory, including a spatial reversal. In the three-panel runway, a delayed matching-to-position procedure was used in which rats were required to find food at the end of the runway after passing through one of three panel gates set into four barriers spaced equally apart along the maze. In addition, mPFC lesions were assessed behaviorally in two behavioral tests known to be sensitive to mPFC dysfunction: the food hoarding paradigm and spontaneous locomotion in the open field. Consistent with the documented effects of mPFC damage, NMDA mPFC lesions impaired food hoarding behavior and increased spontaneous exploratory locomotion. In the Morris water maze and the three-panel runway, mPFC-lesioned rats showed relatively few effects, supporting the conclusion that the damage inflicted to the mPFC had no consequence for the processing of spatial information. However, mPFC lesioned animals showed slower acquisition during both the training trial in the three-panel runway and the reversal training in the Morris water maze. These results suggest that spatial memory did not depend on mPFC integrity in the Morris water maze and the three-panel runway experiments, and address the issue of deficits induced by mPFC lesions in memory tasks dependent on non-mnemonic processes such as attentional processes and/or a reduced behavioral flexibility to environmental changes.

  17. Deep brain stimulation in the lateral orbitofrontal cortex impairs spatial reversal learning.

    Science.gov (United States)

    Klanker, Marianne; Post, Ger; Joosten, Ruud; Feenstra, Matthijs; Denys, Damiaan

    2013-05-15

    Deep Brain Stimulation (DBS) is a successful novel treatment for treatment-resistant obsessive-compulsive disorder and is currently under investigation for addiction and eating disorders. Clinical and preclinical studies have shown functional changes in the orbitofrontal cortex (OFC) following DBS in the ventral capsule/ventral striatum. These findings suggest that DBS can affect neural activity in distant regions that are connected to the site of electrode implantation. However, the behavioral consequences of direct OFC stimulation are not known. Here, we studied the effects of direct stimulation in the lateral OFC on spatial discrimination and reversal learning in rats. Rats were implanted with stimulating electrodes and were trained on a spatial discrimination and reversal learning task. DBS in the OFC did not affect acquisition of a spatial discrimination. Stimulated animals made more incorrect responses during the first reversal. Acquisition of the second reversal was not affected. These results suggest that DBS may inhibit activity in the OFC, or may disrupt output of the OFC to other cortical or subcortical areas, resulting in perseverative behavior or an inability to adapt behavior to altered response-reward contingencies.

  18. Representation of abstract quantitative rules applied to spatial and numerical magnitudes in primate prefrontal cortex.

    Science.gov (United States)

    Eiselt, Anne-Kathrin; Nieder, Andreas

    2013-04-24

    Processing quantity information based on abstract principles is central to intelligent behavior. Neural correlates of quantitative rule selectivity have been identified previously in the prefrontal cortex (PFC). However, whether individual neurons represent rules applied to multiple magnitude types is unknown. We recorded from PFC neurons while monkeys switched between "greater than/less than" rules applied to spatial and numerical magnitudes. A majority of rule-selective neurons responded only to the quantitative rules applied to one specific magnitude type. However, another population of neurons generalized the magnitude principle and represented the quantitative rules related to both magnitudes. This indicates that the primate brain uses rule-selective neurons specialized in guiding decisions related to a specific magnitude type only, as well as generalizing neurons that respond abstractly to the overarching concept "magnitude rules."

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

    Science.gov (United States)

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

    2016-10-01

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

  20. Spatial profile and differential recruitment of GABAB modulate oscillatory activity in auditory cortex.

    Science.gov (United States)

    Oswald, Anne-Marie M; Doiron, Brent; Rinzel, John; Reyes, Alex D

    2009-08-19

    The interplay between inhibition and excitation is at the core of cortical network activity. In many cortices, including auditory cortex (ACx), interactions between excitatory and inhibitory neurons generate synchronous network gamma oscillations (30-70 Hz). Here, we show that differences in the connection patterns and synaptic properties of excitatory-inhibitory microcircuits permit the spatial extent of network inputs to modulate the magnitude of gamma oscillations. Simultaneous multiple whole-cell recordings from connected fast-spiking interneurons and pyramidal cells in L2/3 of mouse ACx slices revealed that for intersomatic distances <50 microm, most inhibitory connections occurred in reciprocally connected (RC) pairs; at greater distances, inhibitory connections were equally likely in RC and nonreciprocally connected (nRC) pairs. Furthermore, the GABA(B)-mediated inhibition in RC pairs was weaker than in nRC pairs. Simulations with a network model that incorporated these features showed strong, gamma band oscillations only when the network inputs were confined to a small area. These findings suggest a novel mechanism by which oscillatory activity can be modulated by adjusting the spatial distribution of afferent input.

  1. Egocentric spatial orientation in a water maze by rats subjected to transection of the fimbria-fornix and/or ablation of the prefrontal cortex

    DEFF Research Database (Denmark)

    Mogensen, Jesper; Moustgaard, Anette; Khan, Usman;

    2005-01-01

    prefrontal cortex, hippocampus, fimbria-fornix, egocentrisk spatial orientering, vandlabyrint, adfærdsstrategier, kognitive strategier, funktionel genopretning, rehabilitering, problemløsning, rotter......prefrontal cortex, hippocampus, fimbria-fornix, egocentrisk spatial orientering, vandlabyrint, adfærdsstrategier, kognitive strategier, funktionel genopretning, rehabilitering, problemløsning, rotter...

  2. The roles of the medial prefrontal cortex and hippocampus in a spatial paired-association task.

    Science.gov (United States)

    Lee, Inah; Solivan, Frances

    2008-05-01

    Although the roles of both the hippocampus and the medial prefrontal cortex (mPFC) have been suggested in a spatial paired-associate memory task, both areas were investigated separately in prior studies. The current study investigated the relative contributions of the hippocampus and mPFC to spatial paired-associate learning within a single behavioral paradigm. In a novel behavioral task, a pair of different objects appeared repeatedly across trials, but in different arms in a radial maze, and different rules were associated with those arms for reward. Specifically, in an "object-in-place" arm, the rat was required to choose a particular object associated with the arm. In a "location-in-place" arm, the animal was required to choose a certain within-arm location (ignoring the object occupying the location). Compared to normal animals, rats with ibotenic acid-based lesions in the hippocampus showed an irrecoverable impairment in performance in both object-in-place and location-in-place arms. When the mPFC was inactivated by muscimol (GABA(A) receptor agonist) in the normal animals with intact hippocampi, they showed the same severe impairment as seen in the hippocampal lesioned rats only in object-in-place arms. The results confirm that the hippocampus is necessary for a biconditional paired-associate task when space is a critical component. The mPFC, however, is more selectively involved in the object-place paired-associate task than in the location-place paired-associate task. The current task powerfully demonstrates an experimental situation in which both the hippocampus and mPFC are required and may serve as a useful paradigm for investigating the neural mechanisms of object-place association.

  3. Neurotoxic lesions of the rat perirhinal cortex fail to disrupt the acquisition or performance of tests of allocentric spatial memory.

    Science.gov (United States)

    Machin, P; Vann, S D; Muir, J L; Aggleton, J P

    2002-04-01

    Rats with neurotoxic lesions of the perirhinal cortex (n = 9) were compared with sham controls (n = 14) on a working memory task in the radial arm maze. Rats were trained under varying levels of proactive interference and with different retention intervals. Finally, performance was assessed when the maze was switched to a novel room. None of these manipulations differentially impaired rats with perirhinal lesions. Rats were next trained on delayed matching-to-place in the water maze. Even with retention delays of 30 min, there was no evidence of a deficit. Although interactions between the perirhinal cortex and hippocampus may be important for integrating object-place information, the perirhinal cortex is often not necessary for tasks that selectively tax allocentric spatial memory.

  4. Temporal and spatial dynamics of thalamus-evoked activity in the anterior cingulate cortex.

    Science.gov (United States)

    Chang, Wei-Chih; Lee, Chia-Ming; Shyu, Bai-Chuang

    2012-10-11

    In the present study, multielectrode array (MEA) recording was used to illustrate the spatial-temporal progression of anterior cingulate cortex (ACC) activity following stimulation of the thalamus in a thalamocingulate pathway-preserved slice. The MEA was placed under the slice that contained the ACC, and 60 channels of extracellular local field potentials evoked by bipolar electrical stimulation within the thalamus were analyzed. Several distinct thalamic-evoked responses were identified. The early negative component (N1; amplitude, -35.7 ± 5.9 μV) emerged in layer VI near the cingulum 8.4 ± 0.5 ms after stimulation. N1 progressed upward to layers V and II/III in a lateral-to-medial direction. Subsequently, a positive component (P; amplitude, 27.0 ± 3.2 μV) appeared 12.0 ± 0.6 ms after stimulation in layer VI. At 26.8 ± 1.1 ms, a second negative component (N2; amplitude, -20.9 ± 2.7 μV) became apparent in layers II/III and V, followed by a more ventrolateral component (N3; amplitude, -18.9 ± 2.9 μV) at 42.8 ± 2.6 ms. These two late components spread downward to layer VI in a medial-to-lateral direction. The trajectory paths of the evoked components were consistently represented with varied medial thalamic stimulation intensities and sites. Both AMPA/kainate and N-methyl-D-aspartate-type glutamate receptors involved in monosynaptic and polysynaptic transmission participated in this thalamocortical pathway. Morphine mainly diminished the two negative synaptic components, and this suppressive effect was reversed by naloxone. The present study confirmed that functional thalamocingulate activity was preserved in the brain-slice preparation. The thalamus-evoked responses were activated and progressed along a deep surface-deep trajectory loop across the ACC layers. Glutamatergic neurotransmitters were crucially involved in information processing. Opioid interneurons may play a modulatory role in regulating the signal flows in the cingulate cortex.

  5. Prefrontal Cortex and Neostriatum Self-Stimulation In the Rat : Differential Effects Produced by Apomorphine

    NARCIS (Netherlands)

    Mora, F.; Phillips, A.G.; Koolhaas, J.M.; Rolls, E.T.

    1976-01-01

    In a dose-response experiment, the effects of intraperitoneal injections of the dopamine receptor agonist, apomorphine (0.075, 0.15, 0.3, 0.6 and 1.2 mg/kg) were studied on self-stimulation elicited from electrodes implanted in the medial and sulcal prefrontal cortex and caudate-putamen in the rat.

  6. Study on Spatial Evolution of Producer Service in Hangzhou City

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    <正>1. Recent development in the study on producer serviceThe producer service refers to the service provided for production and business activities, instead of for individual consumers. As the mid-term input service, it

  7. Imidacloprid toxicity impairs spatial memory of echolocation bats through neural apoptosis in hippocampal CA1 and medial entorhinal cortex areas.

    Science.gov (United States)

    Hsiao, Chun-Jen; Lin, Ching-Lung; Lin, Tian-Yu; Wang, Sheue-Er; Wu, Chung-Hsin

    2016-04-13

    It has been reported that the decimation of honey bees was because of pesticides of imidacloprid. The imidacloprid is a wildly used neonicotinoid insecticide. However, whether imidacloprid toxicity interferes with the spatial memory of echolocation bats is still unclear. Thus, we compared the spatial memory of Formosan leaf-nosed bats, Hipposideros terasensis, before and after chronic treatment with a low dose of imidacloprid. We observed that stereotyped flight patterns of echolocation bats that received chronic imidacloprid treatment were quite different from their originally learned paths. We further found that neural apoptosis in hippocampal CA1 and medial entorhinal cortex areas of echolocation bats that received imidacloprid treatment was significantly enhanced in comparison with echolocation bats that received sham treatment. Thus, we suggest that imidacloprid toxicity may interfere with the spatial memory of echolocation bats through neural apoptosis in hippocampal CA1 and medial entorhinal cortex areas. The results provide direct evidence that pesticide toxicity causes a spatial memory disorder in echolocation bats. This implies that agricultural pesticides may pose severe threats to the survival of echolocation bats.

  8. Chronic Stress Impairs Prefrontal Cortex-Dependent Response Inhibition and Spatial Working Memory

    Science.gov (United States)

    Mika, Agnieszka; Mazur, Gabriel J.; Hoffman, Ann N.; Talboom, Joshua S.; Bimonte-Nelson, Heather A.; Sanabria, Federico; Conrad, Cheryl D.

    2012-01-01

    Chronic stress leads to neurochemical and structural alterations in the prefrontal cortex (PFC) that correspond to deficits in PFC-mediated behaviors. The present study examined the effects of chronic restraint stress on response inhibition (using a response-withholding task, fixed-minimum interval schedule of reinforcement, or FMI), and working memory (using a radial arm water maze, RAWM). Adult male Sprague Dawley rats were first trained on the RAWM and subsequently trained on FMI. Following acquisition of FMI, rats were assigned to a restraint stress (6h/d/28d in wire mesh restrainers) or control condition. Immediately after chronic stress, rats were tested on FMI and subsequently on RAWM. FMI results suggest that chronic stress reduces response inhibition capacity and motivation to initiate the task on selective conditions when food reward was not obtained on the preceding trial. RAWM results suggest that chronic stress produces transient deficits in working memory without altering previously consolidated reference memory. Behavioral measures from FMI failed to correlate with metrics from RAWM except for one in which changes in FMI timing precision negatively correlated with changes in RAWM working memory errors for the controls, a finding that was not observed following chronic stress. Fisher’s r to z transformation revealed no significant differences between control and stress with correlation coefficients. These findings are the first to show that chronic stress impairs both response inhibition and working memory, two behaviors that have never been direct compared within the same animals following chronic stress, using FMI, an appetitive task, and RAWM, a non-appetitive task. PMID:22905921

  9. Chronic stress impairs prefrontal cortex-dependent response inhibition and spatial working memory.

    Science.gov (United States)

    Mika, Agnieszka; Mazur, Gabriel J; Hoffman, Ann N; Talboom, Joshua S; Bimonte-Nelson, Heather A; Sanabria, Federico; Conrad, Cheryl D

    2012-10-01

    Chronic stress leads to neurochemical and structural alterations in the prefrontal cortex (PFC) that correspond to deficits in PFC-mediated behaviors. The present study examined the effects of chronic restraint stress on response inhibition (using a response-withholding task, the fixed-minimum interval schedule of reinforcement, or FMI), and working memory (using a radial arm water maze, RAWM). Adult male Sprague-Dawley rats were first trained on the RAWM and subsequently trained on FMI. After acquisition of FMI, rats were assigned to a restraint stress (6h/d/28d in wire mesh restrainers) or control condition. Immediately after chronic stress, rats were tested on FMI and subsequently on RAWM. FMI results suggest that chronic stress reduces response inhibition capacity and motivation to initiate the task on selective conditions when sucrose reward was not obtained on the preceding trial. RAWM results suggest that chronic stress produces transient deficits in working memory without altering previously consolidated reference memory. Behavioral measures from FMI failed to correlate with metrics from RAWM except for one in which changes in FMI timing imprecision negatively correlated with changes in RAWM working memory errors for the controls, a finding that was not observed following chronic stress. Fisher's r-to-z transformation revealed no significant differences between control and stress groups with correlation coefficients. These findings are the first to show that chronic stress impairs both response inhibition and working memory, two behaviors that have never been directly compared within the same animals after chronic stress, using FMI, an appetitive task, and RAWM, a nonappetitive task.

  10. Preconditioning of Spatial and Auditory Cues: Roles of the Hippocampus, Frontal Cortex, and Cue-Directed Attention

    Directory of Open Access Journals (Sweden)

    Andrew C. Talk

    2016-12-01

    Full Text Available Loss of function of the hippocampus or frontal cortex is associated with reduced performance on memory tasks, in which subjects are incidentally exposed to cues at specific places in the environment and are subsequently asked to recollect the location at which the cue was experienced. Here, we examined the roles of the rodent hippocampus and frontal cortex in cue-directed attention during encoding of memory for the location of a single incidentally experienced cue. During a spatial sensory preconditioning task, rats explored an elevated platform while an auditory cue was incidentally presented at one corner. The opposite corner acted as an unpaired control location. The rats demonstrated recollection of location by avoiding the paired corner after the auditory cue was in turn paired with shock. Damage to either the dorsal hippocampus or the frontal cortex impaired this memory ability. However, we also found that hippocampal lesions enhanced attention directed towards the cue during the encoding phase, while frontal cortical lesions reduced cue-directed attention. These results suggest that the deficit in spatial sensory preconditioning caused by frontal cortical damage may be mediated by inattention to the location of cues during the latent encoding phase, while deficits following hippocampal damage must be related to other mechanisms such as generation of neural plasticity.

  11. Aberrant parietal cortex developmental trajectories in girls with Turner syndrome and related visual-spatial cognitive development: a preliminary study.

    Science.gov (United States)

    Green, Tamar; Chromik, Lindsay C; Mazaika, Paul K; Fierro, Kyle; Raman, Mira M; Lazzeroni, Laura C; Hong, David S; Reiss, Allan L

    2014-09-01

    Turner syndrome (TS) arises from partial or complete absence of the X-chromosome in females. Girls with TS show deficits in visual-spatial skills as well as reduced brain volume and surface area in the parietal cortex which supports these cognitive functions. Thus, measuring the developmental trajectory of the parietal cortex and the associated visual-spatial cognition in TS may provide novel insights into critical brain-behavior associations. In this longitudinal study, we acquired structural MRI data and assessed visual-spatial skills in 16 (age: 8.23 ± 2.5) girls with TS and 13 age-matched controls over two time-points. Gray and white matter volume, surface area and cortical thickness were calculated from surfaced based segmentation of bilateral parietal cortices, and the NEPSY Arrows subtest was used to assess visual-spatial ability. Volumetric and cognitive scalars were modeled to obtain estimates of age-related change. The results show aberrant growth of white matter volume (P = 0.011, corrected) and surface area (P = 0.036, corrected) of the left superior parietal regions during childhood in girls with TS. Other parietal sub-regions were significantly smaller in girls with TS at both time-points but did not show different growth trajectories relative to controls. Furthermore, we found that visual-spatial skills showed a widening deficit for girls with TS relative to controls (P = 0.003). Young girls with TS demonstrate an aberrant trajectory of parietal cortical and cognitive development during childhood. Elucidating aberrant neurodevelopmental trajectories in this population is critical for determining specific stages of brain maturation that are particularly dependent on TS-related genetic and hormonal factors. © 2014 Wiley Periodicals, Inc.

  12. Attraction of position preference by spatial attention throughout human visual cortex

    NARCIS (Netherlands)

    Klein, Barrie P.|info:eu-repo/dai/nl/36939755X; Harvey, Ben M.|info:eu-repo/dai/nl/318755319; Dumoulin, Serge O.|info:eu-repo/dai/nl/314406514

    2014-01-01

    Voluntary spatial attention concentrates neural resources at the attended location. Here, we examined the effects of spatial attention on spatial position selectivity in humans. We measured population receptive fields (pRFs) using high-field functional MRI (fMRI) (7T) while subjects performed an

  13. Attraction of position preference by spatial attention throughout human visual cortex

    NARCIS (Netherlands)

    Klein, Barrie P.; Harvey, Ben M.; Dumoulin, Serge O.

    2014-01-01

    Voluntary spatial attention concentrates neural resources at the attended location. Here, we examined the effects of spatial attention on spatial position selectivity in humans. We measured population receptive fields (pRFs) using high-field functional MRI (fMRI) (7T) while subjects performed an att

  14. The Role of Right Inferior Parietal Cortex in Auditory Spatial Attention: A Repetitive Transcranial Magnetic Stimulation Study.

    Directory of Open Access Journals (Sweden)

    Debra S Karhson

    Full Text Available Behavioral studies support the concept of an auditory spatial attention gradient by demonstrating that attentional benefits progressively diminish as distance increases from an attended location. Damage to the right inferior parietal cortex can induce a rightward attention bias, which implicates this region in the construction of attention gradients. This study used event-related potentials (ERPs to define attention-related gradients before and after repetitive transcranial magnetic stimulation (rTMS to the right inferior parietal cortex. Subjects (n = 16 listened to noise bursts at five azimuth locations (left to right: -90°, -45°, 0° midline, +45°, +90° and responded to stimuli at one target location (-90°, +90°, separate blocks. ERPs as a function of non-target location were examined before (baseline and after 0.9 Hz rTMS. Results showed that ERP attention gradients were observed in three time windows (frontal 230-340, parietal 400-460, frontal 550-750 ms. Significant transient rTMS effects were seen in the first and third windows. The first window had a voltage decrease at the farthest location when attending to either the left or right side. The third window had on overall increase in positivity, but only when attending to the left side. These findings suggest that rTMS induced a small contraction in spatial attention gradients within the first time window. The asymmetric effect of attended location on gradients in the third time window may relate to neglect of the left hemispace after right parietal injury. Together, these results highlight the role of the right inferior parietal cortex in modulating frontal lobe attention network activity.

  15. Competition for attentional resources between low spatial frequency content of emotional images and a foreground task in early visual cortex.

    Science.gov (United States)

    Müller, Matthias M; Gundlach, Christopher

    2017-03-01

    Low spatial frequency (LSF) image content has been proposed to play a superior functional role in emotional content extraction via the magnocellular pathway biasing attentional resources toward emotional content in visual cortex. We investigated whether emotionally unpleasant complex images that were presented either unfiltered or with LSF content only in the background while subjects performed a foreground task will withdraw more attentional resources from the task compared to unemotional, neutral images (distraction paradigm). We measured steady-state visual evoked potentials (SSVEPs) driven by flickering stimuli of a foreground task. Unfiltered unpleasant images resulted in a significant reduction of SSVEP amplitude compared to neutral images. No statistically significant differences were found with LSF background images. In a behavioral control experiment, we found no significant differences for complexity ratings between unfiltered and LSF pictures. Content identification was possible for unfiltered and LSF picture (correct responses > 74%). An additional EEG study examined typical emotion-related components for complex images presented either as unfiltered, LSF, or high spatial frequency (HSF, as an additional control) filtered, unpleasant, and neutral images. We found a significant main effect of emotional valence in the early posterior negativity. Late positive potential differences were only found for unfiltered and HSF images. Results suggest that, while LSF content is sufficient to allow for content and emotional cue extraction when images were presented alone, LSF content is not salient enough to serve as emotional distractor that withdraws attentional resources from a foreground task in early visual cortex. © 2016 Society for Psychophysiological Research.

  16. Mental space travel: damage to posterior parietal cortex prevents egocentric navigation and reexperiencing of remote spatial memories.

    Science.gov (United States)

    Ciaramelli, Elisa; Rosenbaum, R Shayna; Solcz, Stephanie; Levine, Brian; Moscovitch, Morris

    2010-05-01

    The ability to navigate in a familiar environment depends on both an intact mental representation of allocentric spatial information and the integrity of systems supporting complementary egocentric representations. Although the hippocampus has been implicated in learning new allocentric spatial information, converging evidence suggests that the posterior parietal cortex (PPC) might support egocentric representations. To date, however, few studies have examined long-standing egocentric representations of environments learned long ago. Here we tested 7 patients with focal lesions in PPC and 12 normal controls in remote spatial memory tasks, including 2 tasks reportedly reliant on allocentric representations (distance and proximity judgments) and 2 tasks reportedly reliant on egocentric representations (landmark sequencing and route navigation; see Rosenbaum, Ziegler, Winocur, Grady, & Moscovitch, 2004). Patients were unimpaired in distance and proximity judgments. In contrast, they all failed in route navigation, and left-lesioned patients also showed marginally impaired performance in landmark sequencing. Patients' subjective experience associated with navigation was impoverished and disembodied compared with that of the controls. These results suggest that PPC is crucial for accessing remote spatial memories within an egocentric reference frame that enables both navigation and reexperiencing. Additionally, PPC was found to be necessary to implement specific aspects of allocentric navigation with high demands on spontaneous retrieval.

  17. Role of the thalamic nucleus reuniens in mediating interactions between the hippocampus and medial prefrontal cortex during spatial working memory

    Directory of Open Access Journals (Sweden)

    Amy L Griffin

    2015-03-01

    Full Text Available Despite decades of research, the neural mechanisms of spatial working memory remain poorly understood. Although the dorsal hippocampus is known to be critical for memory-guided behavior, experimental evidence suggests that spatial working memory depends not only on the hippocampus itself, but also on the circuit comprised of the hippocampus and the medial prefrontal cortex (mPFC. Disruption of hippocampal-mPFC interactions may result in failed transfer of spatial and contextual information processed by the hippocampus to the circuitry in mPFC responsible for decision making and goal-directed behavior. Oscillatory synchrony between the hippocampus and mPFC has been shown to increase in tasks with high spatial working memory demand. However, the mechanisms and circuitry supporting hippocampal-mPFC interactions during these tasks is unknown. The midline thalamic nucleus reuniens (RE is reciprocally connected to both the hippocampus and the mPFC and has been shown to be critical for a variety of working memory tasks. Therefore, it is likely that hippocampal-mPFC oscillatory synchrony is modulated by RE activity. This article will review the anatomical connections between the hippocampus, mPFC and RE along with the behavioral studies that have investigated the effects of RE disruption on working memory task performance. The article will conclude with suggestions for future directions aimed at identifying the specific role of the RE in regulating functional interactions between the hippocampus and the PFC and investigating the degree to which these interactions contribute to spatial working memory.

  18. rTMS over bilateral inferior parietal cortex induces decrement of spatial sustained attention

    Science.gov (United States)

    Lee, Jeyeon; Ku, Jeonghun; Han, Kiwan; Park, Jinsick; Lee, Hyeongrae; Kim, Kyung Ran; Lee, Eun; Husain, Masud; Yoon, Kang Jun; Kim, In Young; Jang, Dong Pyo; Kim, Sun I.

    2013-01-01

    Sustained attention is an essential brain function that enables a subject to maintain attention level over the time of a task. In previous work, the right inferior parietal lobe (IPL) has been reported as one of the main brain regions related to sustained attention, however, the right lateralization of vigilance/sustained attention is unclear because information about the network for sustained attention is traditionally provided by neglect patients who typically have right brain damage. Here, we investigated sustained attention by applying a virtual lesion technique, transcranial magnetic stimulation (TMS), over the left and right superior parietal lobe (SPL) and IPL. We used two different types of visual sustained attention tasks: spatial (location based) and non-spatial (feature based). When the participants performed the spatial task, repetitive TMS (rTMS) over either the right or left IPL induced a significant decrement of sustained attention causing a progressive increment of errors and response time. In contrast, participants' performance was not changed by rTMS on the non-spatial task. Also, omission errors (true negative) gradually increased with time on right and left IPL rTMS conditions, while commission errors (false positive) were relatively stable. These findings suggest that the maintenance of attention, especially in tasks regarding spatial location, is not uniquely lateralized to the right IPL, but may also involve participation of the left IPL. PMID:23403477

  19. rTMS over bilateral inferior parietal cortex induces decrement of spatial sustained attention

    Directory of Open Access Journals (Sweden)

    Jeyeon eLee

    2013-02-01

    Full Text Available Sustained attention is an essential brain function that enables a subject to maintain attention level over the time of a task. In previous work, the right inferior parietal lobe (IPL has been reported as one of the main brain regions related to sustained attention, however, the right lateralization of vigilance/sustained attention is unclear because information about the network for sustained attention is traditionally provided by neglect patients who typically have right brain damage. Here, we investigated sustained attention by applying a virtual lesion technique, transcranial magnetic stimulation (TMS, over the left and right superior parietal lobe (SPL and IPL. We used two different types of visual sustained attention tasks: spatial (location based and non-spatial (feature based. When the participants performed the spatial task, repetitive TMS (rTMS over either the right or left IPL induced a significant decrement of sustained attention causing a progressive increment of errors and response time. In contrast, participants’ performance was not changed by rTMS on the non-spatial task. Also, omission errors (true negative gradually increased with time on right and left IPL rTMS conditions, while commission errors (false positive were relatively stable. These findings suggest that the maintenance of attention, especially in tasks regarding spatial location, is not uniquely lateralized to the right IPL, but may also involve participation of the left IPL as well.

  20. Dorsal hippocampus and medial prefrontal cortex each contribute to the retrieval of a recent spatial memory in rats.

    Science.gov (United States)

    Cholvin, Thibault; Loureiro, Michaël; Cassel, Raphaelle; Cosquer, Brigitte; Herbeaux, Karin; de Vasconcelos, Anne Pereira; Cassel, Jean-Christophe

    2016-01-01

    Systems-level consolidation models propose that recent memories are initially hippocampus-dependent. When remote, they are partially or completely dependent upon the medial prefrontal cortex (mPFC). An implication of the mPFC in recent memory, however, is still debated. Different amounts of muscimol (MSCI 0, 30, 50, 80 and 250 ng in 1 µL PBS) were used to assess the impact of inactivation of the dorsal hippocampus (dHip) or the mPFC (targeting the prelimbic cortex) on a 24-h delayed retrieval of a platform location that rats had learned drug-free in a water maze. The two smallest amounts of MSCI (30 and 50 ng) did not affect recall, whatever the region. 80 ng MSCI infused into the dHip disrupted spatial memory retrieval, as did the larger amount. Infusion of MSCI into the mPFC did not alter performance in the 0-80 ng range. At 250 ng, it induced an as dramatic memory impairment as after efficient dHip inactivation. Stereological quantifications showed that 80 ng MSCI in the dHip and 250 ng MSCI in the mPFC induced a more than 80% reduction of c-Fos expression, suggesting that, beyond the amounts infused, it is the magnitude of the neuronal activity decrease which is determinant as to the functional outcome of the inactivation. Because, based on the literature, even 250 ng MSCI is a small amount, our results point to a contribution of the mPFC to the recall of a recently acquired spatial memory and thereby extend our knowledge about the functions of this major actor of cognition.

  1. Spatial variability in cortex-muscle coherence investigated with magnetoencephalography and high-density surface electromyography.

    Science.gov (United States)

    Piitulainen, Harri; Botter, Alberto; Bourguignon, Mathieu; Jousmäki, Veikko; Hari, Riitta

    2015-11-01

    Cortex-muscle coherence (CMC) reflects coupling between magnetoencephalography (MEG) and surface electromyography (sEMG), being strongest during isometric contraction but absent, for unknown reasons, in some individuals. We used a novel nonmagnetic high-density sEMG (HD-sEMG) electrode grid (36 mm × 12 mm; 60 electrodes separated by 3 mm) to study effects of sEMG recording site, electrode derivation, and rectification on the strength of CMC. Monopolar sEMG from right thenar and 306-channel whole-scalp MEG were recorded from 14 subjects during 4-min isometric thumb abduction. CMC was computed for 60 monopolar, 55 bipolar, and 32 Laplacian HD-sEMG derivations, and two derivations were computed to mimic "macroscopic" monopolar and bipolar sEMG (electrode diameter 9 mm; interelectrode distance 21 mm). With unrectified sEMG, 12 subjects showed statistically significant CMC in 91-95% of the HD-sEMG channels, with maximum coherence at ∼25 Hz. CMC was about a fifth stronger for monopolar than bipolar and Laplacian derivations. Monopolar derivations resulted in most uniform CMC distributions across the thenar and in tightest cortical source clusters in the left rolandic hand area. CMC was 19-27% stronger for HD-sEMG than for "macroscopic" monopolar or bipolar derivations. EMG rectification reduced the CMC peak by a quarter, resulted in a more uniformly distributed CMC across the thenar, and provided more tightly clustered cortical sources than unrectifed sEMGs. Moreover, it revealed CMC at ∼12 Hz. We conclude that HD-sEMG, especially with monopolar derivation, can facilitate detection of CMC and that individual muscle anatomy cannot explain the high interindividual CMC variability.

  2. Old cortex, new contexts: Re-purposing spatial perception for social cognition

    Directory of Open Access Journals (Sweden)

    Carolyn eParkinson

    2013-10-01

    Full Text Available Much of everyday mental life involves information that we cannot currently perceive directly, from contemplating the strengths of friendships to reasoning about the contents of other minds. Despite their primacy to everyday human functioning, and in particular, to human sociality, the mechanisms that support abstract thought are poorly understood. An explanatory framework that has gained traction recently in cognitive neuroscience is exaptation, or the re-purposing of evolutionarily old circuitry to carry out new functions. We argue for the utility of applying this concept to social cognition. Convergent behavioral and neuroscientific evidence suggests that humans co-opt mechanisms originally devoted to spatial perception for more abstract domains of cognition (e.g., temporal reasoning. Preliminary evidence suggests that some aspects of social cognition also involve the exaptation of substrates originally evolved for processing physical space. We discuss the potential for future work to test more directly if cortical substrates for spatial processing were exapted for social cognition, and in so doing, to improve our understanding of how humans evolved mechanisms for navigating an exceptionally complex social world.

  3. Old cortex, new contexts: re-purposing spatial perception for social cognition.

    Science.gov (United States)

    Parkinson, Carolyn; Wheatley, Thalia

    2013-01-01

    Much of everyday mental life involves information that we cannot currently perceive directly, from contemplating the strengths of friendships to reasoning about the contents of other minds. Despite their primacy to everyday human functioning, and in particular, to human sociality, the mechanisms that support abstract thought are poorly understood. An explanatory framework that has gained traction recently in cognitive neuroscience is exaptation, or the re-purposing of evolutionarily old circuitry to carry out new functions. We argue for the utility of applying this concept to social cognition. Convergent behavioral and neuroscientific evidence suggests that humans co-opt mechanisms originally devoted to spatial perception for more abstract domains of cognition (e.g., temporal reasoning). Preliminary evidence suggests that some aspects of social cognition also involve the exaptation of substrates originally evolved for processing physical space. We discuss the potential for future work to test more directly if cortical substrates for spatial processing were exapted for social cognition, and in so doing, to improve our understanding of how humans evolved mechanisms for navigating an exceptionally complex social world.

  4. Spatial segregation of somato-sensory and pain activations in the human operculo-insular cortex.

    Science.gov (United States)

    Mazzola, Laure; Faillenot, Isabelle; Barral, Fabrice-Guy; Mauguière, François; Peyron, Roland

    2012-03-01

    The role of operculo-insular region in the processing of somato-sensory inputs, painful or not, is now well established. However, available maps from previous literature show a substantial overlap of cortical areas activated by these stimuli, and the region referred to as the "secondary somatosensory area (SII)" is widely distributed in the parietal operculum. Differentiating SII from posterior insula cortex, which is anatomically contiguous, is not easy, explaining why the "operculo-insular" label has been introduced to describe activations by somatosensory stimuli in this cortical region. Based on the recent cyto-architectural parcellation of the human insular/SII cortices (Eickhoff et al., 2006, Kurth et al., 2010), the present study investigates with functional MRI (fMRI), whether these structural subdivisions could subserve distinct aspects of discriminative somato-sensory functions, including pain. Responses to five types of stimuli applied on the left hand of 25 healthy volunteers were considered: i) tactile stimuli; ii) passive movements; iii) innocuous cold stimuli; iv) non-noxious warm and v) heat pain. Our results show different patterns of activation depending on the type of somato-sensory stimulation. The posterior part of SII (OP1 area), contralateral to stimuli, was the only sub-region activated by all type of stimuli and might therefore be considered as a common cortical target for different types of somato-sensory inputs. Proprioceptive stimulation by passive finger movements activated the posterior part of SII (OP1 sub-region) bilaterally and the contralateral median part of insula (PreCG and MSG). Innocuous cooling activated the contralateral posterior part of SII (OP1) and the dorsal posterior and median part of insula (OP2, PostCG). Pain stimuli induced the most widespread and intense activation that was bilateral in SII (OP1, OP4) and distributed to all sub-regions of contralateral insula (except OP2) and to the anterior part of the

  5. Spatiotopic coding of BOLD signal in human visual cortex depends on spatial attention.

    Directory of Open Access Journals (Sweden)

    Sofia Crespi

    Full Text Available The neural substrate of the phenomenological experience of a stable visual world remains obscure. One possible mechanism would be to construct spatiotopic neural maps where the response is selective to the position of the stimulus in external space, rather than to retinal eccentricities, but evidence for these maps has been inconsistent. Here we show, with fMRI, that when human subjects perform concomitantly a demanding attentive task on stimuli displayed at the fovea, BOLD responses evoked by moving stimuli irrelevant to the task were mostly tuned in retinotopic coordinates. However, under more unconstrained conditions, where subjects could attend easily to the motion stimuli, BOLD responses were tuned not in retinal but in external coordinates (spatiotopic selectivity in many visual areas, including MT, MST, LO and V6, agreeing with our previous fMRI study. These results indicate that spatial attention may play an important role in mediating spatiotopic selectivity.

  6. The spatial context of free-ranging Hawaiian spinner dolphins (Stenella longirostris) producing acoustic signals

    NARCIS (Netherlands)

    Lammers, MO; Schotten, M; Au, WWL

    2006-01-01

    To improve our understanding of how dolphins use acoustic signals in the wild, a three-hydrophone towed array was used to investigate the spatial occurrence of Hawaiian spinner dolphins (Stenella longirostris) relative to each other as they produced whistles, burst pulses, and echolocation clicks. G

  7. Spatial relationship between flavoprotein fluorescence and the hemodynamic response in the primary visual cortex of alert macaque monkeys

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    Yevgeniy B Sirotin

    2010-06-01

    Full Text Available Flavoprotein fluorescence imaging (FFI is a novel intrinsic optical signal that is steadily gaining ground as a valuable imaging tool in neuroscience research due to its closer relationship with local metabolism relative to the more commonly used hemodynamic signals. We have developed a technique for FFI imaging in the primary visual cortex (V1 of alert monkeys. Due to the nature of neurovascular coupling, hemodynamic signals are known to spread beyond the locus of metabolic activity. To determine whether FFI signals could provide a more focal measure of cortical activity in alert animals, we compared FFI and hemodynamic point spreads (i.e. responses to a minimal visual stimulus and functional mapping signals over V1 in macaques performing simple fixation tasks. FFI responses were biphasic, with an early and focal fluorescence increase followed by a delayed and spatially broader fluorescence decrease. As expected, the early fluorescence increase, indicating increased local oxidative metabolism, was somewhat narrower than the simultaneously observed hemodynamic response. However, the later FFI decrease was broader than the hemodynamic response and started prior to the cessation of visual stimulation suggesting different mechanisms underlying the two phases of the fluorescence signal. FFI mapping signals were free of vascular artifacts and comparable in amplitude to hemodynamic mapping signals. These results indicate that the FFI response may be a more local and direct indicator of cortical metabolism than the hemodynamic response in alert animals.

  8. Ultrafast single-shot imaging of laser-produced plasmas via spatial division and routing

    Science.gov (United States)

    Yeola, Sarang; Kuk, Donghoon; Kim, Ki-Yong

    2017-01-01

    We have developed a single-shot imaging camera, which can capture ultrafast events occurring on femtosecond and picosecond time scales. The working principle of this camera relies on spatial division and routing of femtosecond laser pulses. Here we have employed simple optics such as mirrors to produce multiple, time-delayed laser pulses and to project time-evolving images onto separate standard cameras. This spatial division and routing method has been tested with a femtosecond amplified laser in visualizing the evolution of laser-induced ionization in air and ablation in solids in single-shots. The number of frames is currently limited to 4 but can be increased further to N x N by using 3D printed optics for spatial division and routing. Work supported by the National Science Foundation (NSF) under Award No. 1351455.

  9. Sustained visual-spatial attention produces costs and benefits in response time and evoked neural activity.

    Science.gov (United States)

    Mangun, G R; Buck, L A

    1998-03-01

    This study investigated the simple reaction time (RT) and event-related potential (ERP) correlates of biasing attention towards a location in the visual field. RTs and ERPs were recorded to stimuli flashed randomly and with equal probability to the left and right visual hemifields in the three blocked, covert attention conditions: (i) attention divided equally to left and right hemifield locations; (ii) attention biased towards the left location; or (iii) attention biased towards the right location. Attention was biased towards left or right by instructions to the subjects, and responses were required to all stimuli. Relative to the divided attention condition, RTs were significantly faster for targets occurring where more attention was allocated (benefits), and slower to targets where less attention was allocated (costs). The early P1 (100-140 msec) component over the lateral occipital scalp regions showed attentional benefits. There were no amplitude modulations of the occipital N1 (125-180 msec) component with attention. Between 200 and 500 msec latency, a late positive deflection (LPD) showed both attentional costs and benefits. The behavioral findings show that when sufficiently induced to bias attention, human observers demonstrate RT benefits as well as costs. The corresponding P1 benefits suggest that the RT benefits of spatial attention may arise as the result of modulations of visual information processing in the extrastriate visual cortex.

  10. Spatial Frequency Dependence of the Human Visual Cortex Response on Temporal Frequency Modulation Studied by fMRI

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    A. Mirzajani

    2006-07-01

    Full Text Available Background/Objective: The brain response to temporal frequencies (TF has been already reported. However, there is no study on different TF with respect to various spatial frequencies (SF. Materials and Methods: Functional magnetic resonance imaging (fMRI was done by a 1.5 T General Electric system for 14 volunteers (9 males and 5 females, aged 19–26 years during square-wave reversal checkerboard visual stimulation with different temporal frequencies of 4, 6, 8 and 10 Hz in 2 states of low SF of 0.4 and high SF of 8 cycles/degree (cpd. All subjects had normal visual acuity of 20/20 based on Snellen’s fraction in each eye with good binocular vision and normal visual field based on confrontation test. The mean luminance of the entire checkerboard was 161.4 cd/m2 and the black and white check contrast was 96%. The activation map was created using the data obtained from the block designed fMRI study. Pixels with a Z score above a threshold of 2.3, at a statistical significance level of 0.05, were considered activated. The average percentage blood oxygenation level dependent (BOLD signal change for all activated pixels within the occipital lobe, multiplied by the total number of activated pixels within the occipital lobe, was used as an index for the magnitude of the fMRI signal at each state of TF&SF. Results: The magnitude of the fMRI signal in response to different TF’s was maximum at 6 Hz for a high SF value of 8 cpd; it was however, maximum at a TF of 8 Hz for a low SF of 0.4 cpd. Conclusion: The results of this study agree with those of animal invasive neurophysiologic studies showing SF and TF selectivity of neurons in visual cortex. These results can be useful for vision therapy and selecting visual tasks in fMRI studies.

  11. Spatial variation of peat soil properties in the oil-producing region of northeastern Sakhalin

    Science.gov (United States)

    Lipatov, D. N.; Shcheglov, A. I.; Manakhov, D. V.; Zavgorodnyaya, Yu. A.; Rozanova, M. S.; Brekhov, P. T.

    2017-07-01

    Morphology and properties of medium-deep oligotrophic peat, oligotrophic peat gley, pyrogenic oligotrophic peat gley, and peat gley soils on subshrub-cotton grass-sphagnum bogs and in swampy larch forests of northeastern Sakhalin have been studied. Variation in the thickness and reserves of litters in the studied bog and forest biogeocenoses has been analyzed. The profile distribution and spatial variability of moisture, density, ash, and pHKCl in separate groups of peat soils have been described. The content and spatial variability of petroleum hydrocarbons have been considered in relation to the accumulation of natural bitumoids by peat soils and the technogenic pressing in the oil-producing region. Variation of each parameter at different distances (10, 50, and 1000 m) has been estimated using a hierarchical sampling scheme. The spatial conjugation of soil parameters has been studied by factor analysis using the principal components method and Spearman correlation coefficients. Regression equations have been proposed to describe relationships of ash content with soil density and content of petroleum hydrocarbons in peat horizons.

  12. Spatial and temporal characteristics of VHF radiation source produced by lightning in supercell thunderstorms

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yijun; MENG Qing; P. R. Krehbiel; LIU Xinsheng; ZHOU Xiuji

    2004-01-01

    The three-dimensional temporal and spatial characteristics of VHF radiation events produced by lightning discharges in three supercell thunderstorms have been analyzed based on the data measured by the lightning mapping array system with high time and space resolution. The results indicate that lightning hole (lighting free region) with about 5-6 km in diameter or lighting ring (annular lighting free region) is associated with the strong updraft in thunderstorm. The lasting time of lightning holes is either short or long, being about 20 min in a tornado-producing thunderstorm. The lightning holes appear before the occurrence of tornado. The lightning hole is the most obvious during the occurrence of tornado and some self-existent lighting radiation events appear at a height of 15-16 km. The lightning channels of inter-cloud (IC) lightning discharge exhibit clockwise rotary structures and do not have clear bilevel structures in the vicinity of the tornado. The lightning holes are corresponding to the strong updraft region. The temporal and spatial distribution of lightning radiation events reveals the structure of strong updraft in supercell thunderstorms.Positive cloud-to-ground (CG) lightning discharges dominate in these thunderstorms and the peak of positive CG lightning flash rate appears, with the maximum of 6 per minute, after or before the occurrence of tornado.

  13. Where am I and how will I get there from here? A role for posterior parietal cortex in the integration of spatial information and route planning.

    Science.gov (United States)

    Calton, Jeffrey L; Taube, Jeffrey S

    2009-02-01

    The ability of an organism to accurately navigate from one place to another requires integration of multiple spatial constructs, including the determination of one's position and direction in space relative to allocentric landmarks, movement velocity, and the perceived location of the goal of the movement. In this review, we propose that while limbic areas are important for the sense of spatial orientation, the posterior parietal cortex is responsible for relating this sense with the location of a navigational goal and in formulating a plan to attain it. Hence, the posterior parietal cortex is important for the computation of the correct trajectory or route to be followed while navigating. Prefrontal and motor areas are subsequently responsible for executing the planned movement. Using this theory, we are able to bridge the gap between the rodent and primate literatures by suggesting that the allocentric role of the rodent PPC is largely analogous to the egocentric role typically emphasized in primates, that is, the integration of spatial orientation with potential goals in the planning of goal-directed movements.

  14. Blockade of IP[subscript 3]-Mediated SK Channel Signaling in the Rat Medial Prefrontal Cortex Improves Spatial Working Memory

    Science.gov (United States)

    Brennan, Avis R.; Dolinsky, Beth; Vu, Mai-Anh T.; Stanley, Marion; Yeckel, Mark F.; Arnsten, Amy F. T.

    2008-01-01

    Planning and directing thought and behavior require the working memory (WM) functions of prefrontal cortex. WM is compromised by stress, which activates phosphatidylinositol (PI)-mediated IP[subscript 3]-PKC intracellular signaling. PKC overactivation impairs WM operations and in vitro studies indicate that IP[subscript 3] receptor (IP[subscript…

  15. Prefrontal cortex contributions to visual-spatial working memory%前额叶损伤患者的视-空间工作记忆改变

    Institute of Scientific and Technical Information of China (English)

    席春华; 朱幼玲; 黄治飞; 郭翠萍; 汪凯

    2010-01-01

    Objective To investigated visual-spatial working memory deficits in patients with focal brain damage involving different subregions of the prefrontal cortex.Methods Twenty patients with lesions in the prefrontal cortex and 20 healthy controls performed visual-object and visual-spatial working memory tasks,including a face-recognition and a spatial delayed-response.Results Compared with health controls (72.9%±6.1%),patients with lesions in ventral prefrontal cortex(VPFC) demonstrated an impairment of a face-recognition task(46.4%±11.4%,U=1.00,P<0.01);Patients with lesions in dorsolateral prefrontal cortex (DLPFC) showed impairment on both visual-object and visual-spatial working memory tasks (50.4%±15.1%,72.6%±18.6%,respectively),indicating significant reduced in a compare to controls (72.9%±6.1%.89.4%±10.1%,U=-20.5,59.5,both P<0.01).There wag no difference in two working memory tasks between patients with lesions in left prefrontal cortex and patients with lesions in right prefrontal cortex:and between patients with lesions in left VPFC and patients with lesions in right VPFC.Patients with lesions in left DLPFC and those in right DLPFC also didn't show significant difference on performance in object or spatial working memory.Conclusions The results confirmed that patients with lesions in prefrontal cortex had deficits of visual-spatial working memory.The results also supported a separation of function with the prefrontal cortex into two distinct subregions for visual-spatial working memory.%目的 探讨前额叶不同亚区损伤患者的视-空间工作记忆障碍.方法 将20例前额叶不同亚区损伤患者以及20名与其人口学资料相匹配的健康人作为被试,采用视觉面孔和视觉空间的延迟匹配任务对上述2组进行视-空间工作记忆测试.结果 与健康对照组(72.9%±6.1%)相比,前额叶腹侧(ventral prefrontal cortex,VPFC)损伤的患者视觉客体工作记忆的正确率(46.4%±11.4%)明显下

  16. Temporal and spatial characteristics of lightning-produced nitrogen oxides in China

    Science.gov (United States)

    Fengxia, Guo; Min, Bao; Yijun, Mu; Zupei, Liu; Yawen, Li; Haifeng, Shi

    2016-11-01

    Tropospheric NO2 vertical column densities (NO2VCDs) retrieved from the Global Ozone Monitoring Experiment-2 satellite spectrometer, as well as lightning flashes measured by an Optical Transient Detector and Lightning Image Sensor from 1997 to 2013 are used to investigate spatial and temporal characteristics of lightning-produced nitrogen oxides (LNOX) under the recent period of rapid and locally-unbalanced economic development in China. Correlations between spatial distributions of lightning flashes and monthly mean tropospheric NO2VCDs were analyzed over this period. Mean production of LNOX per flash is 330 mol[N]/flash which was estimated using the correlation between lightning flashes and monthly mean tropospheric NO2VCD for the Tibetan Plateau. Using this correlation, the spatial and temporal characteristics of the ratio of LNOX to tropospheric NOX in China were determined. Results show that the ratio of LNOX to the tropospheric NOX is small in eastern regions, having a developed industrial sector and dense population, but relatively large in western regions, with a developing industrial sector and sparser population. The annual mean value of LNOX contributing to tropospheric NOX is 7.5% in China, which is lower than global averages (10-20%). The difference in interannual variability of LNOX production contributing to tropospheric NOX in different areas is distinct, ranging from high to low values for the Tibetan Plateau, Pearl River Delta, Yangtze River Delta and Beijing-Tianjin-Hebei regions, respectively. This indicates that lightning had a large influence on the column density of tropospheric NOX on the Tibetan Plateau, a region typically used as a sensitivity indicator for climate change. Lightning had less influence on atmospheric environments of the Pearl River Delta, Yangtze River Delta and Beijing-Tianjin-Hebei regions.

  17. Temporal and spatial distribution of metabotropic glutamate receptor 5 during development in the rat cortex and hippocampus

    Institute of Scientific and Technical Information of China (English)

    Xinli Xiao; Ming Hu; Pengbo Yang; Lin Zhang; Xinlin Chen; Yong Liu

    2011-01-01

    Metabotropic glutamate receptor 5 (mGluR5) is expressed by neurons in zones of active neurogenesis and is involved in the development of neural stem cells in vivo and in vitro. We examined the expression of mGluR5 in the cortex and hippocampus of rats during various prenatal and postnatal periods using immunohistochemistry. During prenatal development, mGluR5 was primarily localized to neuronal somas in the forebrain. During early postnatal periods, the receptor was mainly present on somas in the cortex. mGluR5 immunostaining was visible in apical dendrites and in the neuropil of neurons and persisted throughout postnatal development. During this period, pyramidal neurons were strongly labeled for the receptor. In the hippocampal CA1 region, mGluR5 immunoreactivity was more intense in the stratum oriens, stratum radiatum, and lacunosum moleculare at P0, P5 and P10 relative to P60. mGluR5 expression increased significantly in the molecular layer and decreased significantly in the granule cell layer of the dentate gyrus at P5, P10 and P60 in comparison with P0. Furthermore, some mGluR5-positive cells were also bromodeoxyuridine- or NeuroD-positive in the dentate gyrus at P14. These results demonstrate that mGluR5 has a differential expression pattern in the cortex and hippocampus during early growth, suggesting a role for this receptor in the control of domain specific brain developmental events.

  18. GAD67 deficiency in parvalbumin interneurons produces deficits in inhibitory transmission and network disinhibition in mouse prefrontal cortex.

    Science.gov (United States)

    Lazarus, Matthew S; Krishnan, Keerthi; Huang, Z Josh

    2015-05-01

    In mammalian neocortex, the delicate balance of neural circuits is regulated by a rich repertoire of inhibitory control mechanisms mediated by diverse classes of GABAergic interneurons. A key step common to all GABAergic neurons is the synthesis of GABA, catalyzed by 2 isoforms of glutamic acid decarboxylases (GAD). Among these, GAD67 is the rate-limiting enzyme. GAD67 level is regulated by neural activity and is altered in multiple neuropsychiatric disorders. The significance of altered GAD67 levels on inhibitory transmission, however, remains unclear. The presence of GAD65, postsynaptic GABA receptor regulation, and the diversity of cortical interneurons make the link from GAD67 levels to GABA transmission less than straightforward. Here, we selectively removed one allele of the GAD67 gene, Gad1, in PV interneurons in juvenile mice. We found substantial deficits in transmission from PV to pyramidal neurons in prefrontal cortex, along with increases of pyramidal cell excitability and excitation/inhibition balance in PV cells. Synaptic deficits recovered in adult mice, suggesting engagement of homeostatic and compensatory mechanisms. These results demonstrate that GAD67 levels directly influence synaptic inhibition. Thus, GAD67 deficiency in PV cells likely contributes to cortical dysfunction in disease states; the reversibility of synaptic deficits suggests nonpermanent damage to inhibitory circuitry.

  19. Differences in Visual-Spatial Input May Underlie Different Compression Properties of Firing Fields for Grid Cell Modules in Medial Entorhinal Cortex.

    Science.gov (United States)

    Raudies, Florian; Hasselmo, Michael E

    2015-11-01

    Firing fields of grid cells in medial entorhinal cortex show compression or expansion after manipulations of the location of environmental barriers. This compression or expansion could be selective for individual grid cell modules with particular properties of spatial scaling. We present a model for differences in the response of modules to barrier location that arise from different mechanisms for the influence of visual features on the computation of location that drives grid cell firing patterns. These differences could arise from differences in the position of visual features within the visual field. When location was computed from the movement of visual features on the ground plane (optic flow) in the ventral visual field, this resulted in grid cell spatial firing that was not sensitive to barrier location in modules modeled with small spacing between grid cell firing fields. In contrast, when location was computed from static visual features on walls of barriers, i.e. in the more dorsal visual field, this resulted in grid cell spatial firing that compressed or expanded based on the barrier locations in modules modeled with large spacing between grid cell firing fields. This indicates that different grid cell modules might have differential properties for computing location based on visual cues, or the spatial radius of sensitivity to visual cues might differ between modules.

  20. Mental "Space" Travel: Damage to Posterior Parietal Cortex Prevents Egocentric Navigation and Reexperiencing of Remote Spatial Memories

    Science.gov (United States)

    Ciaramelli, Elisa; Rosenbaum, R. Shayna; Solcz, Stephanie; Levine, Brian; Moscovitch, Morris

    2010-01-01

    The ability to navigate in a familiar environment depends on both an intact mental representation of allocentric spatial information and the integrity of systems supporting complementary egocentric representations. Although the hippocampus has been implicated in learning new allocentric spatial information, converging evidence suggests that the…

  1. An Integrated Photogrammetric and Spatial Database Management System for Producing Fully Structured Data Using Aerial and Remote Sensing Images

    Directory of Open Access Journals (Sweden)

    Farshid Farnood Ahmadi

    2009-03-01

    Full Text Available 3D spatial data acquired from aerial and remote sensing images by photogrammetric techniques is one of the most accurate and economic data sources for GIS, map production, and spatial data updating. However, there are still many problems concerning storage, structuring and appropriate management of spatial data obtained using these techniques. According to the capabilities of spatial database management systems (SDBMSs; direct integration of photogrammetric and spatial database management systems can save time and cost of producing and updating digital maps. This integration is accomplished by replacing digital maps with a single spatial database. Applying spatial databases overcomes the problem of managing spatial and attributes data in a coupled approach. This management approach is one of the main problems in GISs for using map products of photogrammetric workstations. Also by the means of these integrated systems, providing structured spatial data, based on OGC (Open GIS Consortium standards and topological relations between different feature classes, is possible at the time of feature digitizing process. In this paper, the integration of photogrammetric systems and SDBMSs is evaluated. Then, different levels of integration are described. Finally design, implementation and test of a software package called Integrated Photogrammetric and Oracle Spatial Systems (IPOSS is presented.

  2. Effect of Insulin on Visuo-Spatial Memory and Histology of Cerebral Cortex in the Presence or Absence of Nitric Oxide Inhibition.

    Science.gov (United States)

    Yarube, I U; Ayo, J O; Fatihu, M Y; Magaji, R A; Umar, I A; Alhassan, A W; Saleh, M Ia

    2017-03-06

    Insulin has emerged from its traditional 'peripheral' glucose-lowering function to become increasingly regarded as a brain hormone that controls a wide range of functions including learning and memory. Insulin action on learning and memory is linked to nitric oxide (NO) signalling, but its effects on memory and histology of cerebral cortex in conditions of varied NO availability is unclear. This research sought to determine the effect of insulin on visuo-spatial learning, memory and histology of cerebral cortex during NO deficiency. Twenty-four mice weighing 21-23 g, were divided into four groups (n = 6) and treated daily for seven days with 0.2 ml distilled water subcutaneously (s.c.) (control), 10 I.U/kg insulin s.c., 10 I.U/kg insulin + 50 mg/kg L-NAME intraperitoneally (i.p.), and 50 mg/kg i.p. L-NAME s.c., respectively. The 3-day MWM paradigm was used to assess memory. Brain tissue was examined for histological changes. There was no significant difference between day 1 and day 2 latencies for all the groups. The mice in all (but L-NAME) groups spent more time in the target quadrant, and the difference was significant within but not between groups. There was significant reduction in number of platform site crossings (4.83 ± 0.5, 0.67 ± 0.3, 0.50 ± 0.3 and 0.50 ± 0.3 for control, insulin, insulin+L-NAME and L-NAME groups, respectively) in all the groups compared to control. Normal histology of the cortex and absence of histological lesions were observed in brain slides of control and treatment groups. It was concluded that insulin administration impairs visuo-spatial memory to a greater extent in the presence of NO block, and to a lesser extent in the absence of NO block. Nitric oxide has a role in insulin-induced memory impairment. Insulin administration in the presence or absence of NO block had no effect on histology of cortex.

  3. [Visual evoked potentials produced by monocular flash stimuli in the cerebral cortex of the rabbit. I. Typography].

    Science.gov (United States)

    Pérez-Cobo, J C; Ruiz-Beramendi, M; Pérez-Arroyo, M

    1990-12-01

    The visually evoked potentials in the hemisphere contralateral to the stimulated eye in rabbit, can be described topographically as follows. While a positive wave (P1) begins forming in the anterior zones and in the V I binocular zone, the N0 wave, at times very large, is produced in a more occipital zone, which corresponds to the visual streak. Immediately afterwards, the positivity, P1, practically invades the whole of the hemisphere. After this, the N1 wave which is produced in the most posterior parts of the V I, begins forming. The whole phenomenon comes to an end when the P2 wave is generated in the most occipital zones.

  4. A study of the spatial protein organization of the postsynaptic density isolated from porcine cerebral cortex and cerebellum.

    Science.gov (United States)

    Yun-Hong, Yen; Chih-Fan, Chuang; Chia-Wei, Chang; Yen-Chung, Chang

    2011-10-01

    Postsynaptic density (PSD) is a protein supramolecule lying underneath the postsynaptic membrane of excitatory synapses and has been implicated to play important roles in synaptic structure and function in mammalian central nervous system. Here, PSDs were isolated from two distinct regions of porcine brain, cerebral cortex and cerebellum. SDS-PAGE and Western blotting analyses indicated that cerebral and cerebellar PSDs consisted of a similar set of proteins with noticeable differences in the abundance of various proteins between these samples. Subsequently, protein localization in these PSDs was analyzed by using the Nano-Depth-Tagging method. This method involved the use of three synthetic reagents, as agarose beads whose surface was covalently linked with a fluorescent, photoactivable, and cleavable chemical crosslinker by spacers of varied lengths. After its application was verified by using a synthetic complex consisting of four layers of different proteins, the Nano-Depth-Tagging method was used here to yield information concerning the depth distribution of various proteins in the PSD. The results indicated that in both cerebral and cerebellar PSDs, glutamate receptors, actin, and actin binding proteins resided in the peripheral regions within ∼ 10 nm deep from the surface and that scaffold proteins, tubulin subunits, microtubule-binding proteins, and membrane cytoskeleton proteins found in mammalian erythrocytes resided in the interiors deeper than 10 nm from the surface in the PSD. Finally, by using the immunoabsorption method, binding partner proteins of two proteins residing in the interiors, PSD-95 and α-tubulin, and those of two proteins residing in the peripheral regions, elongation factor-1α and calcium, calmodulin-dependent protein kinase II α subunit, of cerebral and cerebellar PSDs were identified. Overall, the results indicate a striking similarity in protein organization between the PSDs isolated from porcine cerebral cortex and cerebellum

  5. Monocular inhibition reveals temporal and spatial changes in gene expression in the primary visual cortex of marmoset.

    Directory of Open Access Journals (Sweden)

    Yuki eNakagami

    2013-04-01

    Full Text Available We investigated the time course of the expression of several activity-dependent genes evoked by visual inputs in the primary visual cortex (V1 in adult marmosets. In order to examine the rapid time course of activity-dependent gene expression, marmosets were first monocularly inactivated by tetrodotoxin (TTX, kept in darkness for two days, and then exposed to various length of light stimulation. Activity-dependent genes including HTR1B, HTR2A, whose activity-dependency were previously reported by us, and well-known immediate early genes (IEGs, c-FOS, ZIF268, and ARC, were examined by in situ hybridization. Using this system, first, we demonstrated the ocular dominance type of gene expression pattern in V1 under this condition. IEGs were expressed in columnar patterns throughout layers II-VI of all the tested monocular marmosets. Second, we showed the regulation of HTR1B and HTR2A expressions by retinal spontaneous activity, because HTR1B and HTR2A mRNA expressions sustained a certain level regardless of visual stimulation and were inhibited by a blockade of the retinal activity with TTX. Third, IEGs dynamically changed its laminar distribution from half an hour to several hours upon a stimulus onset with the unique time course for each gene. The expression patterns of these genes were different in neurons of each layer as well. These results suggest that the regulation of each neuron in the primary visual cortex of marmosets is subjected to different regulation upon the change of activities from retina. It should be related to a highly differentiated laminar structure of primate visual systems, reflecting the functions of the activity-dependent gene expression in marmoset V1.

  6. Mutual information spectrum for selection of event-related spatial components. Application to eloquent motor cortex mapping.

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    Alexei eOssadtchi

    2014-01-01

    Full Text Available Spatial component analysis is often used to explore multidimensional time series data whose sources cannot be measured directly. Several methods may be used to decompose the data into a set of spatial components with temporal loadings. Component selection is of crucial importance, and should be supported by objective criteria. In some applications, the use of a well defined component selection criterion may provide for automation of the analysis.In this paper we describe a novel approach for ranking of spatial components calculated from the EEG or MEG data recorded within evoked response paradigm. Our method is called Mutual Information Spectrum and is based on gauging the amount of mutual information of spatial component temporal loadings with a synthetically created reference signal. We also describe the appropriate randomization based statistical assessment scheme that can be used for selection of components with statistically significant amount of mutual information. Using simulated data with realistic trial to trial variations and SNR corresponding to the real recordings we demonstrate the superior performance characteristics of the described mutual information based measure as compared to a more conventionally used power driven gauge. We also demonstrate the application of the Mutual Information Spectrum for the selection of task-related independent components from real MEG data. We show that the Mutual Information spectrum allows to identify task-related components reliably in a consistent fashion, yielding stable results even from a small number of trials. We conclude that the proposed method fits naturally the information driven nature of ICA and can be used for routine and automatic ranking of independent components calculated from the functional neuroimaging data collected within event-related paradigms.

  7. Pulse re-shaping by using a liquid crystal spatial light modulator and deflector for producing a specific waveform

    Institute of Scientific and Technical Information of China (English)

    Jun Kang; Wei Zhang; Hui Wei; Shaohe Chen; Jianqiang Zhu

    2006-01-01

    @@ A new shaping method for producing nanosecond pulses with specific shape is introduced. When a Gaussian laser pulse passes through an electro-optic deflector, it has been scanned as a line on the focal plane according to time precedence. Through controlling the intensity of transmitted light on each pixel of the liquid crystal spatial light modulator (LCSLM), various complicated pulses can be easily produced. Using this method, various specific shaped pulses with pulse duration varying from 750 ps to 5 ns are achieved.

  8. Sustained Splits of Attention within versus across Visual Hemifields Produce Distinct Spatial Gain Profiles.

    Science.gov (United States)

    Walter, Sabrina; Keitel, Christian; Müller, Matthias M

    2016-01-01

    Visual attention can be focused concurrently on two stimuli at noncontiguous locations while intermediate stimuli remain ignored. Nevertheless, behavioral performance in multifocal attention tasks falters when attended stimuli fall within one visual hemifield as opposed to when they are distributed across left and right hemifields. This "different-hemifield advantage" has been ascribed to largely independent processing capacities of each cerebral hemisphere in early visual cortices. Here, we investigated how this advantage influences the sustained division of spatial attention. We presented six isoeccentric light-emitting diodes (LEDs) in the lower visual field, each flickering at a different frequency. Participants attended to two LEDs that were spatially separated by an intermediate LED and responded to synchronous events at to-be-attended LEDs. Task-relevant pairs of LEDs were either located in the same hemifield ("within-hemifield" conditions) or separated by the vertical meridian ("across-hemifield" conditions). Flicker-driven brain oscillations, steady-state visual evoked potentials (SSVEPs), indexed the allocation of attention to individual LEDs. Both behavioral performance and SSVEPs indicated enhanced processing of attended LED pairs during "across-hemifield" relative to "within-hemifield" conditions. Moreover, SSVEPs demonstrated effective filtering of intermediate stimuli in "across-hemifield" condition only. Thus, despite identical physical distances between LEDs of attended pairs, the spatial profiles of gain effects differed profoundly between "across-hemifield" and "within-hemifield" conditions. These findings corroborate that early cortical visual processing stages rely on hemisphere-specific processing capacities and highlight their limiting role in the concurrent allocation of visual attention to multiple locations.

  9. Distractors less salient than targets capture attention rather than producing non-spatial filtering costs.

    Science.gov (United States)

    Koch, A Isabel; Müller, Hermann J; Zehetleitner, Michael

    2013-09-01

    Distractors that are less salient than the target evoke reaction time interference in the distractor search paradigm. Here, we investigated whether this interference indeed results from spatial attentional capture or merely from non-spatial filtering costs. Target and distractor salience was manipulated parametrically and the modulation of reaction time interference by the distance between both stimuli was taken as an indicator of attentional capture. For distractors that were less salient than the target, we found distance to be predictive of reaction time interference. Moreover, this relationship was modulated by the difference in relative salience of target and distractor: the less salient the distractor was compared to the target, the weaker was the influence of distance. These results are in accordance with the sequential sampling model of salience-based selection by Zehetleitner et al. (Zehetleitner, M., Koch, A.I., Goschy, H., Müller, H.J., 2013. Salience-based selection: Interference by distractors less salient than the target. PLoS ONE 8: e52595.). This model assumes the salience map to be computed by noisy accumulation of sensory evidence. As a result, the salience map output fluctuates around its true value and less salient locations can be denoted as most salient. A distractor less salient than the target can therefore capture attention with a certain probability. We conclude that reaction time interference by less salient distractors in the distractor search paradigm is a result of attentional capture in a proportion of trials, rather than a result of non-spatial filtering costs.

  10. A Five Species Cyclically Dominant Evolutionary Game with Fixed Direction: A New Way to Produce Self-Organized Spatial Patterns

    Directory of Open Access Journals (Sweden)

    Yibin Kang

    2016-08-01

    Full Text Available Cyclically dominant systems are hot issues in academia, and they play an important role in explaining biodiversity in Nature. In this paper, we construct a five-strategy cyclically dominant system. Each individual in our system changes its strategy along a fixed direction. The dominant strategy can promote a change in the dominated strategy, and the dominated strategy can block a change in the dominant strategy. We use mean-field theory and cellular automaton simulation to discuss the evolving characters of the system. In the cellular automaton simulation, we find the emergence of spiral waves on spatial patterns without a migration rate, which suggests a new way to produce self-organized spatial patterns.

  11. Beyond Emotional and Spatial Processes: Cognitive Dysfunction in a Depressive Phenotype Produced by Long Photoperiod Exposure.

    Science.gov (United States)

    Barnes, Abigail K; Smith, Summer B; Datta, Subimal

    2017-01-01

    Cognitive dysfunction in depression has recently been given more attention and legitimacy as a core symptom of the disorder. However, animal investigations of depression-related cognitive deficits have generally focused on emotional or spatial memory processing. Additionally, the relationship between the cognitive and affective disturbances that are present in depression remains obscure. Interestingly, sleep disruption is one aspect of depression that can be related both to cognition and affect, and may serve as a link between the two. Previous studies have correlated sleep disruption with negative mood and impaired cognition. The present study investigated whether a long photoperiod-induced depressive phenotype showed cognitive deficits, as measured by novel object recognition, and displayed a cognitive vulnerability to an acute period of total sleep deprivation. Adult male Wistar rats were subjected to a long photoperiod (21L:3D) or a normal photoperiod (12L:12D) condition. Our results indicate that our long photoperiod exposed animals showed behaviors in the forced swim test consistent with a depressive phenotype, and showed significant deficits in novel object recognition. Three hours of total sleep deprivation, however, did not significantly change novel object recognition in either group, but the trends suggest that the long photoperiod and normal photoperiod groups had different cognitive responses to total sleep deprivation. Collectively, these results underline the extent of cognitive dysfunction present in depression, and suggest that altered sleep plays a role in generating both the affective and cognitive symptoms of depression.

  12. Spatial frequency-based analysis of mean red blood cell speed in single microvessels: investigation of microvascular perfusion in rat cerebral cortex.

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    Joonas Autio

    Full Text Available BACKGROUND: Our previous study has shown that prenatal exposure to X-ray irradiation causes cerebral hypo-perfusion during the postnatal development of central nervous system (CNS. However, the source of the hypo-perfusion and its impact on the CNS development remains unclear. The present study developed an automatic analysis method to determine the mean red blood cell (RBC speed through single microvessels imaged with two-photon microscopy in the cerebral cortex of rats prenatally exposed to X-ray irradiation (1.5 Gy. METHODOLOGY/PRINCIPAL FINDINGS: We obtained a mean RBC speed (0.9±0.6 mm/sec that ranged from 0.2 to 4.4 mm/sec from 121 vessels in the radiation-exposed rats, which was about 40% lower than that of normal rats that were not exposed. These results were then compared with the conventional method for monitoring microvascular perfusion using the arteriovenous transit time (AVTT determined by tracking fluorescent markers. A significant increase in the AVTT was observed in the exposed rats (1.9±0.6 sec as compared to the age-matched non-exposed rats (1.2±0.3 sec. The results indicate that parenchyma capillary blood velocity in the exposed rats was approximately 37% lower than in non-exposed rats. CONCLUSIONS/SIGNIFICANCE: The algorithm presented is simple and robust relative to monitoring individual RBC speeds, which is superior in terms of noise tolerance and computation time. The demonstrative results show that the method developed in this study for determining the mean RBC speed in the spatial frequency domain was consistent with the conventional transit time method.

  13. Spatial dynamics of receptive fields in cat primary visual cortex related to the temporal structure of thalamocortical feedforward activity. Experiments and models.

    Science.gov (United States)

    Suder, Katrin; Funke, Klaus; Zhao, Yongqiang; Kerscher, Nicolas; Wennekers, Thomas; Wörgötter, Florentin

    2002-06-01

    We investigated how changes in the temporal firing rate of thalamocortical activity affect the spatiotemporal structure of receptive field (RF) subunits in cat primary visual cortex. Spike activity of 67 neurons (48 simple, 19 complex cells) was extracellulary recorded from area 17/18 of anesthetized and paralyzed cats. A total of 107 subfields (on/off) were mapped by applying a reverse correlation technique to the activity elicited by bright and dark rectangles flashed for 300 ms in a 20x10 grid. We found that the width of the (suprathreshold) discharge fields shrank on average by 22% during this 300-ms-long stimulus presentation time. Fifty-eight subfields (54%) shrank by more than 20% of peak width and only ten (less than 10%) showed a slight increase over time. The main size reduction took place 40-60 ms after response onset, which corresponded to the transition from transient peak firing to tonic visual activity in thalamocortical relay cells (TC). The experimentally obtained RFs were then fitted with the aid of a neural field model of the primary visual pathway. Assuming a Gaussian-shaped spatial sensitivity profile across the RF subfield width, the model allowed us to estimate the subthreshold RF (depolarization field, D-field) from the minimal discharge field (MDF). The model allowed us to test to what degree the temporal dynamics of thalamocortical activity contributes to the spatiotemporal changes of cortical RFs. To this end, we performed the fitting procedure either with a pure feedforward model or with a field model that also included intracortical feedback. Spatial and temporal parameters obtained from fits of the experimental RFs matched closely to those achieved by simulating a pure feedforward system with the field model but were not compatible with additional intracortical feedback. Thus, our results show that dot stimulation, which optimally excites thalamocortical cells, leads to a shrinkage with respect to the size of the RF subfield at the

  14. Spatial and temporal correlation of water quality parameters of produced waters from devonian-age shale following hydraulic fracturing.

    Science.gov (United States)

    Barbot, Elise; Vidic, Natasa S; Gregory, Kelvin B; Vidic, Radisav D

    2013-03-19

    The exponential increase in fossil energy production from Devonian-age shale in the Northeastern United States has highlighted the management challenges for produced waters from hydraulically fractured wells. Confounding these challenges is a scant availability of critical water quality parameters for this wastewater. Chemical analyses of 160 flowback and produced water samples collected from hydraulically fractured Marcellus Shale gas wells in Pennsylvania were correlated with spatial and temporal information to reveal underlying trends. Chloride was used as a reference for the comparison as its concentration varies with time of contact with the shale. Most major cations (i.e., Ca, Mg, Sr) were well-correlated with chloride concentration while barium exhibited strong influence of geographic location (i.e., higher levels in the northeast than in southwest). Comparisons against brines from adjacent formations provide insight into the origin of salinity in produced waters from Marcellus Shale. Major cations exhibited variations that cannot be explained by simple dilution of existing formation brine with the fracturing fluid, especially during the early flowback water production when the composition of the fracturing fluid and solid-liquid interactions influence the quality of the produced water. Water quality analysis in this study may help guide water management strategies for development of unconventional gas resources.

  15. Spatial Patterns and Temperature Predictions of Tuna Fatty Acids: Tracing Essential Nutrients and Changes in Primary Producers.

    Science.gov (United States)

    Pethybridge, Heidi R; Parrish, Christopher C; Morrongiello, John; Young, Jock W; Farley, Jessica H; Gunasekera, Rasanthi M; Nichols, Peter D

    2015-01-01

    Fatty acids are among the least understood nutrients in marine environments, despite their profile as key energy components of food webs and that they are essential to all life forms. Presented here is a novel approach to predict the spatial-temporal distributions of fatty acids in marine resources using generalized additive mixed models. Fatty acid tracers (FAT) of key primary producers, nutritional condition indices and concentrations of two essential long-chain (≥C20) omega-3 fatty acids (EFA) measured in muscle of albacore tuna, Thunnus alalunga, sampled in the south-west Pacific Ocean were response variables. Predictive variables were: location, time, sea surface temperature (SST) and chlorophyll-a (Chla), and phytoplankton biomass at time of catch and curved fork length. The best model fit for all fatty acid parameters included fish length and SST. The first oceanographic contour maps of EFA and FAT (FATscapes) were produced and demonstrated clear geographical gradients in the study region. Predicted changes in all fatty acid parameters reflected shifts in the size-structure of dominant primary producers. Model projections show that the supply and availability of EFA are likely to be negatively affected by increases in SST especially in temperate waters where a 12% reduction in both total fatty acid content and EFA proportions are predicted. Such changes will have large implications for the availability of energy and associated health benefits to high-order consumers. Results convey new concerns on impacts of projected climate change on fish-derived EFA in marine systems.

  16. Monoallelic deletion of the microRNA biogenesis gene Dgcr8 produces deficits in the development of excitatory synaptic transmission in the prefrontal cortex

    Directory of Open Access Journals (Sweden)

    Barker Alison J

    2011-04-01

    Full Text Available Abstract Background Neuronal phenotypes associated with hemizygosity of individual genes within the 22q11.2 deletion syndrome locus hold potential towards understanding the pathogenesis of schizophrenia and autism. Included among these genes is Dgcr8, which encodes an RNA-binding protein required for microRNA biogenesis. Dgcr8 haploinsufficient mice (Dgcr8+/- have reduced expression of microRNAs in brain and display cognitive deficits, but how microRNA deficiency affects the development and function of neurons in the cerebral cortex is not fully understood. Results In this study, we show that Dgcr8+/- mice display reduced expression of a subset of microRNAs in the prefrontal cortex, a deficit that emerges over postnatal development. Layer V pyramidal neurons in the medial prefrontal cortex of Dgcr8+/- mice have altered electrical properties, decreased complexity of basal dendrites, and reduced excitatory synaptic transmission. Conclusions These findings demonstrate that precise microRNA expression is critical for the postnatal development of prefrontal cortical circuitry. Similar defects in neuronal maturation resulting from microRNA deficiency could represent endophenotypes of certain neuropsychiatric diseases of developmental onset.

  17. The Role of Human Parietal Cortex in Attention Networks

    Science.gov (United States)

    Han, Shihui; Jiang, Yi; Gu, Hua; Rao, Hengyi; Mao, Lihua; Cui, Yong; Zhai, Renyou

    2004-01-01

    The parietal cortex has been proposed as part of the neural network for guiding spatial attention. However, it is unclear to what degree the parietal cortex contributes to the attentional modulations of activities of the visual cortex and the engagement of the frontal cortex in the attention network. We recorded behavioural performance and…

  18. Spatial Patterns and Temperature Predictions of Tuna Fatty Acids: Tracing Essential Nutrients and Changes in Primary Producers.

    Directory of Open Access Journals (Sweden)

    Heidi R Pethybridge

    Full Text Available Fatty acids are among the least understood nutrients in marine environments, despite their profile as key energy components of food webs and that they are essential to all life forms. Presented here is a novel approach to predict the spatial-temporal distributions of fatty acids in marine resources using generalized additive mixed models. Fatty acid tracers (FAT of key primary producers, nutritional condition indices and concentrations of two essential long-chain (≥C20 omega-3 fatty acids (EFA measured in muscle of albacore tuna, Thunnus alalunga, sampled in the south-west Pacific Ocean were response variables. Predictive variables were: location, time, sea surface temperature (SST and chlorophyll-a (Chla, and phytoplankton biomass at time of catch and curved fork length. The best model fit for all fatty acid parameters included fish length and SST. The first oceanographic contour maps of EFA and FAT (FATscapes were produced and demonstrated clear geographical gradients in the study region. Predicted changes in all fatty acid parameters reflected shifts in the size-structure of dominant primary producers. Model projections show that the supply and availability of EFA are likely to be negatively affected by increases in SST especially in temperate waters where a 12% reduction in both total fatty acid content and EFA proportions are predicted. Such changes will have large implications for the availability of energy and associated health benefits to high-order consumers. Results convey new concerns on impacts of projected climate change on fish-derived EFA in marine systems.

  19. Volitional reduction of anterior cingulate cortex activity produces decreased cue craving in smoking cessation: a preliminary real-time fMRI study.

    Science.gov (United States)

    Li, Xingbao; Hartwell, Karen J; Borckardt, Jeffery; Prisciandaro, James J; Saladin, Michael E; Morgan, Paul S; Johnson, Kevin A; Lematty, Todd; Brady, Kathleen T; George, Mark S

    2013-07-01

    Numerous research groups are now using analysis of blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) results and relaying back information about regional activity in their brains to participants in the scanner in 'real time'. In this study, we explored the feasibility of self-regulation of frontal cortical activation using real-time fMRI (rtfMRI) neurofeedback in nicotine-dependent cigarette smokers during exposure to smoking cues. Ten cigarette smokers were shown smoking-related visual cues in a 3 Tesla MRI scanner to induce their nicotine craving. Participants were instructed to modify their craving using rtfMRI feedback with two different approaches. In a 'reduce craving' paradigm, participants were instructed to 'reduce' their craving, and decrease the anterior cingulate cortex (ACC) activity. In a separate 'increase resistance' paradigm, participants were asked to increase their resistance to craving and to increase middle prefrontal cortex (mPFC) activity. We found that participants were able to significantly reduce the BOLD signal in the ACC during the 'reduce craving' task (P=0.028). There was a significant correlation between decreased ACC activation and reduced craving ratings during the 'reduce craving' session (P=0.011). In contrast, there was no modulation of the BOLD signal in mPFC during the 'increase resistance' session. These preliminary results suggest that some smokers may be able to use neurofeedback via rtfMRI to voluntarily regulate ACC activation and temporarily reduce smoking cue-induced craving. Further research is needed to determine the optimal parameters of neurofeedback rtfMRI, and whether it might eventually become a therapeutic tool for nicotine dependence. © 2012 The Authors, Addiction Biology © 2012 Society for the Study of Addiction.

  20. Extended exposure to sugar and/or caffeine produces distinct behavioral and neurochemical profiles in the orbitofrontal cortex of rats: Implications for neural function.

    Science.gov (United States)

    Franklin, Jane L; Mirzaei, Mehdi; Wearne, Travis A; Homewood, Judi; Goodchild, Ann K; Haynes, Paul A; Cornish, Jennifer L

    2016-11-01

    Caffeine is a psychostimulant commonly consumed with high levels of sugar. The increased availability of highly caffeinated, high sugar energy drinks could put some consumers at risk of being exposed to high doses of caffeine and sugar. Notably, research that has examined the consequences of this combination is limited. Here, we explored the effect of chronic exposure to caffeine and/or sugar on behavior and protein levels in the orbitofrontal cortex (OFC) of rats. The OFC brain region has been implicated in neuropsychiatric conditions, including obesity and addiction behaviors. Adult male Sprague-Dawley rats were treated for 26 days with control, caffeine (0.6 g/L), 10% sugar, or combination of both. Locomotor behavior was measured on the first and last day of treatment, then 1 week after treatment. Two hours following final behavioral testing, brains were rapidly removed and prepared for proteomic analysis of the OFC. Label-free quantitative shotgun analysis revealed that 21, 12, and 23% of proteins identified in the OFC were differentially expressed by sugar and/or caffeine. The results demonstrate that the intake of high levels of sugar and/or low to moderate levels of caffeine has different behavioral consequences. Moreover, each treatment results in a unique proteomic profile with different implications for neural health. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Morphogenetic and histogenetic roles of the temporal-spatial organization of cell proliferation in the vertebrate corticogenesis as revealed by inter-specific analyses of the optic tectum cortex development

    Directory of Open Access Journals (Sweden)

    Melina eRapacioli

    2016-03-01

    Full Text Available The central nervous system areas displaying the highest structural and functional complexity correspond to the so called cortices, i.e. concentric alternating neuronal and fibrous layers. Corticogenesis, i.e. the development of the cortical organization, depends on the temporal-spatial organization of several developmental events: (a the duration of the proliferative phase of the neuroepithelium, (b the relative duration of symmetric (expansive versus asymmetric (neuronogenic sub phases, (c the spatial organization of each kind of cell division, (e the time of determination and cell cycle exit and (f the time of onset of the postmitotic neuronal migration and (g the time of onset of the neuronal structural and functional differentiation. The first five events depend on molecular mechanisms that perform a fine tuning of the proliferative activity. Changes in any of them significantly influence the cortical size or volume (tangential expansion and radial thickness, morphology, architecture and also impact on neuritogenesis and synaptogenesis affecting the cortical wiring. This paper integrates information, obtained in several species, on the developmental roles of cell proliferation in the development of the optic tectum cortex, a multilayered associative area of the dorsal (alar midbrain. The present review (1 compiles relevant information on the temporal and spatial organization of cell proliferation in different species (fish, amphibians, birds and mammals, (2 revises the main molecular events involved in the isthmic organizer determination and localization, (3 describes how the patterning installed by isthmic organizer is translated into spatially organized neural stem cell proliferation (i.e. by means of growth factors, receptors, transcription factors, signaling pathways, etc. and (4 describes the morpho- and histogenetic effect of a spatially organized cell proliferation in the above mentioned species. A brief section on the optic tectum

  2. Exploring dynamical complexity in diffusion driven predator-prey systems: Effect of toxin producing phytoplankton and spatial heterogeneities

    Energy Technology Data Exchange (ETDEWEB)

    Upadhyay, Ranjit Kumar [Department of Applied Mathematics, Indian School of Mines University, Dhanbad, Jharkhand 826 004 (India)], E-mail: ranjit_ism@yahoo.com; Kumari, Nitu [Department of Applied Mathematics, Indian School of Mines University, Dhanbad, Jharkhand 826 004 (India)], E-mail: nituism@gmail.com; Rai, Vikas [Department of Applied Mathematics, HMR Institute of Technology and Management, GT Karnal Road, Hamidpur, Delhi 110 036 (India)

    2009-10-15

    In this paper, dynamical complexities in two reaction-diffusion (RD) model systems are explored. A spatial heterogeneity in the form of linear spatial gradient in the reproductive growth rate of the phytoplankton is incorporated in both the model systems. Extra mortality of the zooplankton due to toxin production by the phytoplankton is included in the second reaction diffusion model system. Effect of toxin production and spatial heterogeneity in the model systems are studied. Toxin production does not seem to have an appreciable effect on the asymptotic dynamics of the model systems. On the other hand, spatial heterogeneity does influence the dynamics. In particular, it increases the frequency of occurrence of chaos as evident from two dimensional parameter scans. Both these model systems display short term recurrent chaos [Rai V. Chaos in natural populations: edge or wedge? Ecol Complex 2004;1: 127-38] as they reside on 'edges of chaos' (EOC) [Rai V, Upadhyay RK. Evolving to the edge of chaos: chance or necessity? Chaos, Solitons and Fractals 2006;30:1074-87]. This suggests that the ecological systems have a tendency to evolve to EOC. The study corroborates the inferences drawn from an earlier study by Rai and Upadhyay [Rai V, Upadhyay RK. Evolving to the edge of chaos: chance or necessity? Chaos, Solitons and Fractals 2006;30:1074-87]. The system's dynamics is largely unpredictable and admits bursts of short-term predictability.

  3. Water Bodies’ Mapping from Sentinel-2 Imagery with Modified Normalized Difference Water Index at 10-m Spatial Resolution Produced by Sharpening the SWIR Band

    Directory of Open Access Journals (Sweden)

    Yun Du

    2016-04-01

    Full Text Available Monitoring open water bodies accurately is an important and basic application in remote sensing. Various water body mapping approaches have been developed to extract water bodies from multispectral images. The method based on the spectral water index, especially the Modified Normalized Difference Water Index (MDNWI calculated from the green and Shortwave-Infrared (SWIR bands, is one of the most popular methods. The recently launched Sentinel-2 satellite can provide fine spatial resolution multispectral images. This new dataset is potentially of important significance for regional water bodies’ mapping, due to its free access and frequent revisit capabilities. It is noted that the green and SWIR bands of Sentinel-2 have different spatial resolutions of 10 m and 20 m, respectively. Straightforwardly, MNDWI can be produced from Sentinel-2 at the spatial resolution of 20 m, by upscaling the 10-m green band to 20 m correspondingly. This scheme, however, wastes the detailed information available at the 10-m resolution. In this paper, to take full advantage of the 10-m information provided by Sentinel-2 images, a novel 10-m spatial resolution MNDWI is produced from Sentinel-2 images by downscaling the 20-m resolution SWIR band to 10 m based on pan-sharpening. Four popular pan-sharpening algorithms, including Principle Component Analysis (PCA, Intensity Hue Saturation (IHS, High Pass Filter (HPF and À Trous Wavelet Transform (ATWT, were applied in this study. The performance of the proposed method was assessed experimentally using a Sentinel-2 image located at the Venice coastland. In the experiment, six water indexes, including 10-m NDWI, 20-m MNDWI and 10-m MNDWI, produced by four pan-sharpening algorithms, were compared. Three levels of results, including the sharpened images, the produced MNDWI images and the finally mapped water bodies, were analysed quantitatively. The results showed that MNDWI can enhance water bodies and suppressbuilt

  4. Mosquito-Producing Containers, Spatial Distribution, and Relationship between Aedes aegypti Population Indices on the Southern Boundary of its Distribution in South America (Salto, Uruguay)

    Science.gov (United States)

    Basso, César; Caffera, Ruben M.; García da Rosa, Elsa; Lairihoy, Rosario; González, Cristina; Norbis, Walter; Roche, Ingrid

    2012-01-01

    A study was conducted in the city of Salto, Uruguay, to identify mosquito-producing containers, the spatial distribution of mosquitoes and the relationship between the different population indices of Aedes aegypti. On each of 312 premises visited, water-filled containers and immature Ae. aegypti mosquitoes were identified. The containers were counted and classified into six categories. Pupae per person and Stegomyia indices were calculated. Pupae per person were represented spatially. The number of each type of container and number of mosquitoes in each were analyzed and compared, and their spatial distribution was analyzed. No significant differences in the number of the different types of containers with mosquitoes or in the number of mosquitoes in each were found. The distribution of the containers with mosquito was random and the distribution of mosquitoes by type of container was aggregated or highly aggregated. PMID:23128295

  5. Differential role of the dorsal hippocampus, ventro-intermediate hippocampus, and medial prefrontal cortex in updating the value of a spatial goal.

    Science.gov (United States)

    De Saint Blanquat, Paul; Hok, Vincent; Save, Etienne; Poucet, Bruno; Chaillan, Franck A

    2013-05-01

    Encoding of a goal with a specific value while performing a place navigation task involves the medial prefrontal cortex (mPFC) and the dorsal hippocampus (dHPC), and depends on the coordination between mPFC and the ventro-intermediate hippocampus (vHPC).The present work investigates the contribution of mPFC, dHPC, and vHPC when the rat has to update the value of a goal. Rats were trained to navigate to an uncued goal in order to release a food pellet in a continuous place navigation task. When they had reached criterion performance level in the task, they were subjected to a single "flash session" in which they were exposed to an aversive strobe light during goal visits instead of receiving a food reward. Just before the flash session, the GABA(A) agonist muscimol was injected to temporarily inactivate mPFC, dHPC, or vHPC. The ability to recall the changed value of the goal was tested on the next day. We first demonstrate the aversive effect of the strobe light by showing that rats learn to avoid the goal much more rapidly in the flash session than during a simple extinction session in which goal visits are not rewarded. Furthermore, while dHPC inactivation had no effect on learning and recalling the new goal value, vHPC muscimol injections considerably delayed goal value updating during the flash session, which resulted in a slight deficit during recall. In contrast, mPFC muscimol injections induced faster goal value updating but the rats were markedly impaired on recalling the new goal value on the next day. These results suggest that, contrary to mPFC and dHPC, vHPC is required for updating the value of a goal. In contrast, mPFC is necessary for long-term retention of this updating.

  6. Noradrenergic signaling in the medial prefrontal cortex and amygdala differentially regulates vicarious trial-and-error in a spatial decision-making task.

    Science.gov (United States)

    Amemiya, Seiichiro; Kubota, Natsuko; Umeyama, Nao; Nishijima, Takeshi; Kita, Ichiro

    2016-01-15

    In uncertain choice situations, we deliberately search and evaluate possible options before taking an action. Once we form a preference regarding the current situation, we take an action more automatically and with less deliberation. In rats, the deliberation process can be seen in vicarious trial-and-error behavior (VTE), which is a head-orienting behavior toward options at a choice point. Recent neurophysiological findings suggest that VTE reflects the rat's thinking about future options as deliberation, expectation, and planning when rats feel conflict. VTE occurs depending on the demand: an increase occurs during initial learning, and a decrease occurs with progression in learning. However, the brain circuit underlying the regulation of VTE has not been thoroughly examined. In situations in which VTE often appears, the medial prefrontal cortex (mPFC) and the amygdala (AMY) are crucial for learning and decision making. Our previous study reported that noradrenaline regulates VTE. Here, to investigate whether the mPFC and AMY are involved in regulation of VTE, we examined the effects of local injection of clonidine, an alpha2 adrenergic autoreceptor agonist, into either region in rats during VTE and choice behavior during a T-maze choice task. Injection of clonidine into either region impaired selection of the advantageous choice in the task. Furthermore, clonidine injection into the mPFC suppressed occurrence of VTE in the early phase of the task, whereas injection into the AMY inhibited the decrease in VTE in the later phase and thus maintained a high level of VTE throughout the task. These results suggest that the mPFC and AMY play a role in the increase and decrease in VTE, respectively, and that noradrenergic mechanisms mediate the dynamic regulation of VTE over experiences.

  7. Social instability stress in adolescent male rats alters hippocampal neurogenesis and produces deficits in spatial location memory in adulthood.

    Science.gov (United States)

    McCormick, Cheryl M; Thomas, Catherine M; Sheridan, Cheryl S; Nixon, Feather; Flynn, Jennifer A; Mathews, Iva Z

    2012-06-01

    The ongoing development of the hippocampus in adolescence may be vulnerable to stressors. The effects of social instability stress (SS) in adolescence (daily 1 h isolation and change of cage partner postnatal days 30-45) on cell proliferation in the dentate gyrus (DG) in adolescence (on days 33 and 46, experiment 1) and in adulthood (experiment 2) was examined in Long Evans male rats and compared to nonstressed controls (CTL). Additionally, in experiment 2, a separate group of SS and CTL rats was tested on either a spatial (hippocampal-dependent) or nonspatial (nonhippocampal dependent) version of an object memory test and also were used to investigate hippocampal expression of markers of synaptic plasticity. No memory impairment was evident until the SS rats were adults, and the impairment was only on the spatial test. SS rats initially (postnatal day 33) had increased cell proliferation based on counts of Ki67 immunoreactive (ir) cells and greater survival of immature neurons based on counts of doublecortin ir cells on day 46 and in adulthood, irrespective of behavioral testing. Counts of microglia in the DG did not differ by stress group, but behavioral testing was associated with reduced microglia counts compared to nontested rats. As adults, SS and CTL rats did not differ in hippocampal expression of synaptophysin, but compared to CTL rats, SS rats had higher expression of basal calcium/calmodulin-dependent kinase II (CamKII), and lower expression of the phosphorylated CamKII subunit threonine 286, signaling molecules related to synaptic plasticity. The results are contrasted with those from previous reports of chronic stress in adult rats, and we conclude that adolescent stress alters the ongoing development of the hippocampus leading to impaired spatial memory in adulthood, highlighting the heightened vulnerability to stressors in adolescence.

  8. An Improved Method for Producing High Spatial-Resolution NDVI Time Series Datasets with Multi-Temporal MODIS NDVI Data and Landsat TM/ETM+ Images

    Directory of Open Access Journals (Sweden)

    Yuhan Rao

    2015-06-01

    Full Text Available Due to technical limitations, it is impossible to have high resolution in both spatial and temporal dimensions for current NDVI datasets. Therefore, several methods are developed to produce high resolution (spatial and temporal NDVI time-series datasets, which face some limitations including high computation loads and unreasonable assumptions. In this study, an unmixing-based method, NDVI Linear Mixing Growth Model (NDVI-LMGM, is proposed to achieve the goal of accurately and efficiently blending MODIS NDVI time-series data and multi-temporal Landsat TM/ETM+ images. This method firstly unmixes the NDVI temporal changes in MODIS time-series to different land cover types and then uses unmixed NDVI temporal changes to predict Landsat-like NDVI dataset. The test over a forest site shows high accuracy (average difference: −0.0070; average absolute difference: 0.0228; and average absolute relative difference: 4.02% and computation efficiency of NDVI-LMGM (31 seconds using a personal computer. Experiments over more complex landscape and long-term time-series demonstrated that NDVI-LMGM performs well in each stage of vegetation growing season and is robust in regions with contrasting spatial and spatial variations. Comparisons between NDVI-LMGM and current methods (i.e., Spatial and Temporal Adaptive Reflectance Fusion Model (STARFM, Enhanced STARFM (ESTARFM and Weighted Linear Model (WLM show that NDVI-LMGM is more accurate and efficient than current methods. The proposed method will benefit land surface process research, which requires a dense NDVI time-series dataset with high spatial resolution.

  9. Chemosensory Learning in the Cortex

    Directory of Open Access Journals (Sweden)

    Edmund eRolls

    2011-09-01

    Full Text Available Taste is a primary reinforcer. Olfactory-taste and visual-taste association learning takes place in the primate including human orbitofrontal cortex to build representations of flavour. Rapid reversal of this learning can occur using a rule-based learning system that can be reset when an expected taste or flavour reward is not obtained, that is by negative reward prediction error, to which a population of neurons in the orbitofrontal cortex responds. The representation in the orbitofrontal cortex but not the primary taste or olfactory cortex is of the reward value of the visual / olfactory / taste / input as shown by devaluation experiments in which food is fed to satiety, and by correlations with the activations with subjective pleasantness ratings in humans. Sensory-specific satiety for taste, olfactory, visual, and oral somatosensory inputs produced by feeding a particular food to satiety are implemented it is proposed by medium-term synaptic adaptation in the orbitofrontal cortex. Cognitive factors, including word-level descriptions, modulate the representation of the reward value of food in the orbitofrontal cortex, and this effect is learned it is proposed by associative modification of top-down synapses onto neurons activated by bottom-up taste and olfactory inputs when both are active in the orbitofrontal cortex. A similar associative synaptic learning process is proposed to be part of the mechanism for the top-down attentional control to the reward value vs the sensory properties such as intensity of taste and olfactory inputs in the orbitofrontal cortex, as part of a biased activation theory of selective attention.

  10. Chronic glucocorticoids increase hippocampal vulnerability to neurotoxicity under conditions that produce CA3 dendritic retraction but fail to impair spatial recognition memory.

    Science.gov (United States)

    Conrad, Cheryl D; McLaughlin, Katie J; Harman, James S; Foltz, Cainan; Wieczorek, Lindsay; Lightner, Elizabeth; Wright, Ryan L

    2007-08-01

    We previously found that chronic stress conditions producing CA3 dendritic retraction and spatial memory deficits make the hippocampus vulnerable to the neurotoxin ibotenic acid (IBO). The purpose of this study was to determine whether exposure to chronic corticosterone (CORT) under conditions that produce CA3 dendritic retraction would enhance CA3 susceptibility to IBO. Male Sprague Dawley rats were chronically treated for 21 d with CORT in drinking water (400 microg/ml), and half were given daily injections of phenytoin (40 mg/kg), an antiepileptic drug that prevents CA3 dendritic retraction. Three days after treatments stopped, IBO was infused into the CA3 region. Conditions producing CA3 dendritic retraction (CORT and vehicle) exacerbated IBO-induced CA3 damage compared with conditions in which CA3 dendritic retraction was not observed (vehicle and vehicle, vehicle and phenytoin, CORT and phenytoin). Additionally, spatial recognition memory was assessed using the Y-maze, revealing that conditions producing CA3 dendritic retraction failed to impair spatial recognition memory. Furthermore, CORT levels in response to a potentially mild stressor (injection and Y-maze exposure) stayed at basal levels and failed to differ among key groups (vehicle and vehicle, CORT and vehicle, CORT and phenytoin), supporting the interpretations that CORT levels were unlikely to have been elevated during IBO infusion and that the neuroprotective actions of phenytoin were not through CORT alterations. These data are the first to show that conditions with prolonged glucocorticoid elevations leading to structural changes in hippocampal dendritic arbors can make the hippocampus vulnerable to neurotoxic challenges. These findings have significance for many disorders with elevated glucocorticoids that include depression, schizophrenia, Alzheimer's disease, and Cushing's disease.

  11. Arc/Arg3.1 mRNA global expression patterns elicited by memory recall in cerebral cortex differ for remote versus recent spatial memories

    Directory of Open Access Journals (Sweden)

    Pavel A Gusev

    2010-05-01

    Full Text Available The neocortex plays a critical role in the gradual formation and storage of remote declarative memories. Because the circuitry mechanisms of systems-level consolidation are not well understood, the precise cortical sites for memory storage and the nature of enduring memory correlates (mnemonic plasticity are largely unknown. Detailed maps of neuronal activity underlying recent and remote memory recall highlight brain regions that participate in systems consolidation and constitute putative storage sites, and thus may facilitate detection of mnemonic plasticity. To localize cortical regions involved in the recall of a spatial memory task, we trained rats in a water maze and then mapped mRNA expression patterns of a neuronal activity marker Arc/Arg3.1 (Arc upon recall of recent (24 hours after training or remote (one month after training memories and compared them with swimming and naive controls. Arc gene expression was significantly more robust 24 hours after training compared to one month after training. Arc expression diminished in the parietal, cingulate and visual areas, but select segments in the prefrontal, retrosplenial, somatosensory and motor cortical showed similar robust increases in the Arc expression. When Arc expression was compared across select segments of sensory, motor and associative regions within recent and remote memory groups, the overall magnitude and cortical laminar patterns of task-specific Arc expression were similar (stereotypical. Arc mRNA fractions expressed in the upper cortical layers (2/3, 4 increased after both recent and remote recall, while layer 6 fractions decreased only after the recent recall. The data suggest that robust recall of remote memory requires an overall smaller increase in neuronal activity within fewer cortical segments. This activity trend highlights the difficulty in detecting the storage sites and plasticity underlying remote memory. Application of the Arc maps may ameliorate this

  12. Visual Map Shifts based on Whisker-Guided Cues in the Young Mouse Visual Cortex

    Directory of Open Access Journals (Sweden)

    Kohei Yoshitake

    2013-12-01

    Full Text Available Mice navigate nearby space using their vision and whiskers, and young mice learn to integrate these heterogeneous inputs in perceptual space. We found that cortical responses were depressed in the primary visual cortex of young mice after wearing a monocular prism. This depression was uniformly observed in the primary visual cortex and was eliminated by whisker trimming or lesions in the posterior parietal cortex. Compensatory visual map shifts of responses elicited via the eye that had worn the prism were also observed. As a result, cortical responses elicited via each eye were clearly separated when a visual stimulus was placed in front of the mice. A comparison of response areas before and after prism wearing indicated that the map shifts were produced by depression with spatial eccentricity. Visual map shifts based on whisker-guided cues may serve as a model for investigating the cellular and molecular mechanisms underlying higher sensory integration in the mammalian brain.

  13. 国内外生产性服务业空间集聚的研究进展%Research progress of the spatial agglomeration on producer services

    Institute of Scientific and Technical Information of China (English)

    申玉铭; 吴康; 任旺兵

    2009-01-01

    As an important sector in service industry, producer services have become a sig-nificant force to promote the economic growth and reflect the main economic function in China's metropolitan regions since the 1990s. In recent decades, the growth and spatial ag-glomeration of producer services become one of the most important economic phenomena in regions of different scales and the most international metropolises. Based on the review of industrial agglomeration and service industrial location, this paper summarizes the re-On the whole, around regions and metropolitans, many scholars at home and abroad have studied this topic and made much progress. However, there are still some shortcomings in some aspects. Firstly, this study has paid much attention to the spatial patterns, while lit-tle can be found in the published literature about evolution process. Secondly, there have been relatively studies on the impact mechanism of the spatial agglomeration on producer services, thus a law theoretic system has not formed. Thirdly, most of the research meth-ods transform the model that measures manufacturing agglomeration to the producer serv-ices. Besides, its applicability and relevance still need to be further explored. The main study trends and orientations in the future can be summarized as follows: Aiming at the research framework "measurement and identification, patterns and process, factors and mechanisms"; and using integrated approach of qualitative-quantitative and spatial analysis to deepen and improve the geographic research of the spatial agglomeration on producer services.%20世纪90年代以来,作为服务业中重要一支的生产性服务业正成为推动我国大城市经济增长的重要力量和体现城市经济职能的主要方面.本文在对产业集聚和服务业区位等相关理论回顾的基础上,对目前周内外生产性服务业空间集聚的主要研究内容和研究方法进行了详尽梳理.总体来看,围绕着区域和大都

  14. Use of Aerial high resolution visible imagery to produce large river bathymetry: a multi temporal and spatial study over the by-passed Upper Rhine

    Science.gov (United States)

    Béal, D.; Piégay, H.; Arnaud, F.; Rollet, A.; Schmitt, L.

    2011-12-01

    Aerial high resolution visible imagery allows producing large river bathymetry assuming that water depth is related to water colour (Beer-Bouguer-Lambert law). In this paper we aim at monitoring Rhine River geometry changes for a diachronic study as well as sediment transport after an artificial injection (25.000 m3 restoration operation). For that a consequent data base of ground measurements of river depth is used, built on 3 different sources: (i) differential GPS acquisitions, (ii) sounder data and (iii) lateral profiles realized by experts. Water depth is estimated using a multi linear regression over neo channels built on a principal component analysis over red, green and blue bands and previously cited depth data. The study site is a 12 km long reach of the by-passed section of the Rhine River that draws French and German border. This section has been heavily impacted by engineering works during the last two centuries: channelization since 1842 for navigation purposes and the construction of a 45 km long lateral canal and 4 consecutive hydroelectric power plants of since 1932. Several bathymetric models are produced based on 3 different spatial resolutions (6, 13 and 20 cm) and 5 acquisitions (January, March, April, August and October) since 2008. Objectives are to find the optimal spatial resolution and to characterize seasonal effects. Best performances according to the 13 cm resolution show a 18 cm accuracy when suspended matters impacted less water transparency. Discussions are oriented to the monitoring of the artificial reload after 2 flood events during winter 2010-2011. Bathymetric models produced are also useful to build 2D hydraulic model's mesh.

  15. Spatial profiles of electron density, electron temperature, average ionic charge, and EUV emission of laser-produced Sn plasmas for EUV lithography

    Science.gov (United States)

    Sato, Yuta; Tomita, Kentaro; Tsukiyama, Syoichi; Eguchi, Toshiaki; Uchino, Kiichiro; Kouge, Kouichiro; Tomuro, Hiroaki; Yanagida, Tatsuya; Wada, Yasunori; Kunishima, Masahito; Kodama, Takeshi; Mizoguchi, Hakaru

    2017-03-01

    Spatial profiles of the electron density (n e), electron temperature (T e), and average ionic charge (Z) of laser-produced Sn plasmas for EUV lithography, whose conversion efficiency (CE) is sufficiently high for practical use, were measured using a collective Thomson scattering (TS) technique. For plasma production, Sn droplets of 26 µm diameter were used as a fuel. First, a picosecond-pulsed laser was used to expand a Sn target. Next, a CO2 laser was used to generate plasmas. By changing the injection timing of the picosecond and CO2 lasers, three different types of plasmas were generated. The CEs of the three types of plasmas differed, and ranged from 2.8 to 4.0%. Regarding the different plasma conditions, the spatial profiles of n e, T e, and Z clearly differed. However, under all plasma conditions, intense EUV was only observed at a sufficiently high T e (> 25 eV) and in an adequate n e range [1024–(2 × 1025) m‑3]. These plasma parameters lie in the efficient-EUV light source range, as predicted by simulations.

  16. Growth and Spatial Development of Producer Services in China%中国生产性服务业发展与空间分布

    Institute of Scientific and Technical Information of China (English)

    杨帆; 叶嘉安

    2013-01-01

      从分行业的角度探讨了中国生产性服务业的发展特征及其在城市体系中的空间分布。研究表明,中国生产性服务业的发展水平还处在初级阶段,虽然高级别生产性服务业增长较快,但是所占比重较小。空间分布上,生产性服务业倾向于集中在特大城市。由于其在经济发展中发挥重要的作用,这种分布特征重组了城市等级结构和城市之间的经济联系。随着中国经济的持续增长和政府的政策支持,对生产性服务业的需求将大大增加。全球化背景下,发展生产性服务业也成为重要的城市发展战略。但是,生产性服务业不均衡的分布格局决定了大城市和特大城市在新一轮的城市发展中具有更大的竞争力。因此,中小城市在发展生产性服务业时必须进行深入的分析,以免造成用地和资金的浪费。%Producer services are essential sector to facilitate economic growth and shape regional economies. They have experienced dramatic expansion in China in the recent decade. This paper attempts to identify the nature of producer service growth and analyze their spatial development in the Chinese urban system from a disaggregated perspective. The findings suggest that (1) despite their impressive growth over the past decade,producer services accounted for a relatively low share of the national economy in terms of both output and employment;and (2) geographically, producer services are becoming spatially more concentrated across the urban system, which has significantly reorganized urban hierarchy and inter-city connections. Stimulated by economic growth and policy support from the central government,producer services in China are expected to continue to grow at a rapid speed. The development of producer services has become a new and popular strategy for urban development in many Chinese cities in the era of globalization. However, the unequal distribution of

  17. Effect of Panax notoginseng saponins on the expression of beta-amyloid protein in the cortex of the parietal lobe and hippocampus, and spatial learning and memory in a mouse model of senile dementia

    Institute of Scientific and Technical Information of China (English)

    Zhenguo Zhong; Dengpan Wu; Liang Lü; Jinsheng Wang; Wenyan Zhang; Zeqiang Qu

    2008-01-01

    immunohistochemistry. The mRNA content of App, tau, acetylcholinesterase, and synaptophysin (Syp) was tested by real time PCR and RT-PCR.RESULTS: The PCR results show that PNS can downregulate the expression of the App gene and upregulate the expression of the Syp gene in the parietal cortex and hippocampus of SAMP8 mice. The therapeutic effects of the PNS high-dosage group were greater than those of the PNS low-dosage group and the huperzine A group (P < 0.05). The results of the Morris water maze and immunohistochemistry indicated that PNS can improve the capacity for spatial learning and memory in SAMP8 mice, and reduce the content of A β1-40,A β1-42 and expression of App in the brains of SAMP8 mice. The therapeutic effects of the PNS high-dosage group were greater than that of the PNS low-dosage group and the huperzine A group (P < 0.05).CONCLUSION: These results support the hypothesis that PNS plays a therapeutic and protective role on the pathological lesions and learning dysfunction of Alzheimer's disease. The therapeutic effects of PNS for Alzheimer's disease are possibly achieved through downregulating the expression of the App gene and upregulating the expression of the Syp gene. The therapeutic effects of PNS are dose-dependent and are greater than the effect of huperzine A.

  18. Egocentric and allocentric representations in auditory cortex.

    Science.gov (United States)

    Town, Stephen M; Brimijoin, W Owen; Bizley, Jennifer K

    2017-06-01

    A key function of the brain is to provide a stable representation of an object's location in the world. In hearing, sound azimuth and elevation are encoded by neurons throughout the auditory system, and auditory cortex is necessary for sound localization. However, the coordinate frame in which neurons represent sound space remains undefined: classical spatial receptive fields in head-fixed subjects can be explained either by sensitivity to sound source location relative to the head (egocentric) or relative to the world (allocentric encoding). This coordinate frame ambiguity can be resolved by studying freely moving subjects; here we recorded spatial receptive fields in the auditory cortex of freely moving ferrets. We found that most spatially tuned neurons represented sound source location relative to the head across changes in head position and direction. In addition, we also recorded a small number of neurons in which sound location was represented in a world-centered coordinate frame. We used measurements of spatial tuning across changes in head position and direction to explore the influence of sound source distance and speed of head movement on auditory cortical activity and spatial tuning. Modulation depth of spatial tuning increased with distance for egocentric but not allocentric units, whereas, for both populations, modulation was stronger at faster movement speeds. Our findings suggest that early auditory cortex primarily represents sound source location relative to ourselves but that a minority of cells can represent sound location in the world independent of our own position.

  19. Yield and spatial distributions of femtosecond laser-produced protons%飞秒激光作用下质子产额及空间分布

    Institute of Scientific and Technical Information of China (English)

    唐翠明; 王昌军; 王亚平; 王光昶; 张建炜; 郑志坚

    2012-01-01

    在超短超强激光装置SILEX-Ⅰ上,利用HD810辐射变色膜在靶背法线方向测量了质子产额及空间分布.测量结果显示:光学密度与质子流量密切相关,光学密度越大,质子流量就越大;当C8H8厚度相同,Cu厚度增加时,质子产额随辐射变色膜的光学密度平均值减小而减小;当靶相同,激光功率密度越小时,光学密度平均值就越小,则质子产额也越小;实验中还得到了质子呈环状、成丝和圆盘状结构的空间分布,该空间分布的大小与激光焦斑大小无关.%For studying the yield and spatial distributions of protons produced in the interaction of femtosecond laser with plasmas, protons behavior at the normal direction of the rear surface of the target irradiated by ultra-intensity pulse laser irradiated solid targets was explored on SILEX-I laser facility. The yield and .spatial distributions of the protons with different target thicknesses were recorded by radiochromic film (RCF) HD810. The results show that the optics density (OD) is closely correlated with the protons flux, OD values increase with the increasing of proton beam flux; For fixed thickness of C8 H8 layer, the proton beam flux and yield of protons and OD of RCF decrease with the increasing Cu layer thickness; for the same thickness of targets, the OD and yield of protons decrease with the decreases of laser intensity; And the corresponding spatial profile of proton beam shows ring-, filament-, and disc-like distribution. The size of the distribution is independent of laser focus.

  20. Phosphene Perception Relates to Visual Cortex Glutamate Levels and Covaries with Atypical Visuospatial Awareness

    Science.gov (United States)

    Terhune, Devin B.; Murray, Elizabeth; Near, Jamie; Stagg, Charlotte J.; Cowey, Alan; Cohen Kadosh, Roi

    2015-01-01

    Phosphenes are illusory visual percepts produced by the application of transcranial magnetic stimulation to occipital cortex. Phosphene thresholds, the minimum stimulation intensity required to reliably produce phosphenes, are widely used as an index of cortical excitability. However, the neural basis of phosphene thresholds and their relationship to individual differences in visual cognition are poorly understood. Here, we investigated the neurochemical basis of phosphene perception by measuring basal GABA and glutamate levels in primary visual cortex using magnetic resonance spectroscopy. We further examined whether phosphene thresholds would relate to the visuospatial phenomenology of grapheme-color synesthesia, a condition characterized by atypical binding and involuntary color photisms. Phosphene thresholds negatively correlated with glutamate concentrations in visual cortex, with lower thresholds associated with elevated glutamate. This relationship was robust, present in both controls and synesthetes, and exhibited neurochemical, topographic, and threshold specificity. Projector synesthetes, who experience color photisms as spatially colocalized with inducing graphemes, displayed lower phosphene thresholds than associator synesthetes, who experience photisms as internal images, with both exhibiting lower thresholds than controls. These results suggest that phosphene perception is driven by interindividual variation in glutamatergic activity in primary visual cortex and relates to cortical processes underlying individual differences in visuospatial awareness. PMID:25725043

  1. Phosphene Perception Relates to Visual Cortex Glutamate Levels and Covaries with Atypical Visuospatial Awareness.

    Science.gov (United States)

    Terhune, Devin B; Murray, Elizabeth; Near, Jamie; Stagg, Charlotte J; Cowey, Alan; Cohen Kadosh, Roi

    2015-11-01

    Phosphenes are illusory visual percepts produced by the application of transcranial magnetic stimulation to occipital cortex. Phosphene thresholds, the minimum stimulation intensity required to reliably produce phosphenes, are widely used as an index of cortical excitability. However, the neural basis of phosphene thresholds and their relationship to individual differences in visual cognition are poorly understood. Here, we investigated the neurochemical basis of phosphene perception by measuring basal GABA and glutamate levels in primary visual cortex using magnetic resonance spectroscopy. We further examined whether phosphene thresholds would relate to the visuospatial phenomenology of grapheme-color synesthesia, a condition characterized by atypical binding and involuntary color photisms. Phosphene thresholds negatively correlated with glutamate concentrations in visual cortex, with lower thresholds associated with elevated glutamate. This relationship was robust, present in both controls and synesthetes, and exhibited neurochemical, topographic, and threshold specificity. Projector synesthetes, who experience color photisms as spatially colocalized with inducing graphemes, displayed lower phosphene thresholds than associator synesthetes, who experience photisms as internal images, with both exhibiting lower thresholds than controls. These results suggest that phosphene perception is driven by interindividual variation in glutamatergic activity in primary visual cortex and relates to cortical processes underlying individual differences in visuospatial awareness.

  2. Porous TiO2 Nanotubes with Spatially Separated Platinum and CoOx Cocatalysts Produced by Atomic Layer Deposition for Photocatalytic Hydrogen Production.

    Science.gov (United States)

    Zhang, Jiankang; Yu, Zhuobin; Gao, Zhe; Ge, Huibin; Zhao, Shichao; Chen, Chaoqiu; Chen, Shuai; Tong, Xili; Wang, Meihua; Zheng, Zhanfeng; Qin, Yong

    2017-01-16

    Efficient separation of photogenerated electrons and holes, and associated surface reactions, is a crucial aspect of efficient semiconductor photocatalytic systems employed for photocatalytic hydrogen production. A new CoOx /TiO2 /Pt photocatalyst produced by template-assisted atomic layer deposition is reported for photocatalytic hydrogen production on Pt and CoOx dual cocatalysts. Pt nanoclusters acting as electron collectors and active sites for the reduction reaction are deposited on the inner surface of porous TiO2 nanotubes, while CoOx nanoclusters acting as hole collectors and active sites for oxidation reaction are deposited on the outer surface of porous TiO2 nanotubes. A CoOx /TiO2 /Pt photocatalyst, comprising ultra-low concentrations of noble Pt (0.046 wt %) and CoOx (0.019 wt %) deposited simultaneously with one atomic layer deposition cycle, achieves remarkably high photocatalytic efficiency (275.9 μmol h(-1) ), which is nearly five times as high as that of pristine TiO2 nanotubes (56.5 μmol h(-1) ). The highly dispersed Pt and CoOx nanoclusters, porous structure of TiO2 nanotubes with large specific surface area, and the synergetic effect of the spatially separated Pt and CoOx dual cocatalysts contribute to the excellent photocatalytic activity.

  3. Dissociable contributions of the prefrontal cortex to hippocampus- and caudate nucleus-dependent virtual navigation strategies.

    Science.gov (United States)

    Dahmani, Louisa; Bohbot, Véronique D

    2015-01-01

    The hippocampus and the caudate nucleus are critical to spatial- and stimulus-response-based navigation strategies, respectively. The hippocampus and caudate nucleus are also known to be anatomically connected to various areas of the prefrontal cortex. However, little is known about the involvement of the prefrontal cortex in these processes. In the current study, we sought to identify the prefrontal areas involved in spatial and response learning. We used functional magnetic resonance imaging (fMRI) and voxel-based morphometry to compare the neural activity and grey matter density of spatial and response strategy users. Twenty-three healthy young adults were scanned in a 1.5 T MRI scanner while they engaged in the Concurrent Spatial Discrimination Learning Task, a virtual navigation task in which either a spatial or response strategy can be used. In addition to increased BOLD activity in the hippocampus, spatial strategy users showed increased BOLD activity and grey matter density in the ventral area of the medial prefrontal cortex, especially in the orbitofrontal cortex. On the other hand, response strategy users exhibited increased BOLD activity and grey matter density in the dorsal area of the medial prefrontal cortex. Given the prefrontal cortex's role in reward-guided decision-making, we discuss the possibility that the ventromedial prefrontal cortex, including the orbitofrontal cortex, supports spatial learning by encoding stimulus-reward associations, while the dorsomedial prefrontal cortex supports response learning by encoding action-reward associations.

  4. Functional maps of human auditory cortex: effects of acoustic features and attention.

    Directory of Open Access Journals (Sweden)

    David L Woods

    Full Text Available BACKGROUND: While human auditory cortex is known to contain tonotopically organized auditory cortical fields (ACFs, little is known about how processing in these fields is modulated by other acoustic features or by attention. METHODOLOGY/PRINCIPAL FINDINGS: We used functional magnetic resonance imaging (fMRI and population-based cortical surface analysis to characterize the tonotopic organization of human auditory cortex and analyze the influence of tone intensity, ear of delivery, scanner background noise, and intermodal selective attention on auditory cortex activations. Medial auditory cortex surrounding Heschl's gyrus showed large sensory (unattended activations with two mirror-symmetric tonotopic fields similar to those observed in non-human primates. Sensory responses in medial regions had symmetrical distributions with respect to the left and right hemispheres, were enlarged for tones of increased intensity, and were enhanced when sparse image acquisition reduced scanner acoustic noise. Spatial distribution analysis suggested that changes in tone intensity shifted activation within isofrequency bands. Activations to monaural tones were enhanced over the hemisphere contralateral to stimulation, where they produced activations similar to those produced by binaural sounds. Lateral regions of auditory cortex showed small sensory responses that were larger in the right than left hemisphere, lacked tonotopic organization, and were uninfluenced by acoustic parameters. Sensory responses in both medial and lateral auditory cortex decreased in magnitude throughout stimulus blocks. Attention-related modulations (ARMs were larger in lateral than medial regions of auditory cortex and appeared to arise primarily in belt and parabelt auditory fields. ARMs lacked tonotopic organization, were unaffected by acoustic parameters, and had distributions that were distinct from those of sensory responses. Unlike the gradual adaptation seen for sensory responses

  5. Effects of acetylcholine on neuronal properties in entorhinal cortex

    Directory of Open Access Journals (Sweden)

    James G Heys

    2012-07-01

    Full Text Available The entorhinal cortex receives prominent cholinergic innervation from the medial septum and the vertical limb of the diagonal band of Broca (MSDB. To understand how cholinergic neurotransmission can modulate behavior, research has been directed towards identification of the specific cellular mechanisms in entorhinal cortex that can be modulated through cholinergic activity. This review focuses on intrinsic cellular properties of neurons in entorhinal cortex that may underlie functions such as working memory, spatial processing and episodic memory. In particular, the study of stellate cells in medial entorhinal has resulted in discovery of correlations between physiological properties of these neurons and properties of the unique spatial representation that is demonstrated through unit recordings of neurons in medial entorhinal cortex from awake-behaving animals. A separate line of investigation has demonstrated persistent firing behavior among neurons in entorhinal cortex that is enhanced by cholinergic activity and could underlie working memory. There is also evidence that acetylcholine plays a role in modulation of synaptic transmission that could also enhance mnemonic function in entorhinal cortex. Finally, the local circuits of entorhinal cortex demonstrate a variety of interneuron physiology, which is also subject to cholinergic modulation. Together these effects alter the dynamics of entorhinal cortex to underlie the functional role of acetylcholine in memory.

  6. Assessing the Effect of Early Visual Cortex Transcranial Magnetic Stimulation on Working Memory Consolidation.

    Science.gov (United States)

    van Lamsweerde, Amanda E; Johnson, Jeffrey S

    2017-07-01

    Maintaining visual working memory (VWM) representations recruits a network of brain regions, including the frontal, posterior parietal, and occipital cortices; however, it is unclear to what extent the occipital cortex is engaged in VWM after sensory encoding is completed. Noninvasive brain stimulation data show that stimulation of this region can affect working memory (WM) during the early consolidation time period, but it remains unclear whether it does so by influencing the number of items that are stored or their precision. In this study, we investigated whether single-pulse transcranial magnetic stimulation (spTMS) to the occipital cortex during VWM consolidation affects the quantity or quality of VWM representations. In three experiments, we disrupted VWM consolidation with either a visual mask or spTMS to retinotopic early visual cortex. We found robust masking effects on the quantity of VWM representations up to 200 msec poststimulus offset and smaller, more variable effects on WM quality. Similarly, spTMS decreased the quantity of VWM representations, but only when it was applied immediately following stimulus offset. Like visual masks, spTMS also produced small and variable effects on WM precision. The disruptive effects of both masks and TMS were greatly reduced or entirely absent within 200 msec of stimulus offset. However, there was a reduction in swap rate across all time intervals, which may indicate a sustained role of the early visual cortex in maintaining spatial information.

  7. Neuropsychology of prefrontal cortex

    OpenAIRE

    2008-01-01

    The history of clinical frontal lobe study is long and rich which provides valuable insights into neuropsychologic determinants of functions of prefrontal cortex (PFC). PFC is often classified as multimodal association cortex as extremely processed information from various sensory modalities is integrated here in a precise fashion to form the physiologic constructs of memory, perception, and diverse cognitive processes. Human neuropsychologic studies also support the notion of different funct...

  8. [Prefrontal cortex in memory and attention processes].

    Science.gov (United States)

    Allegri, R F; Harris, P

    The role of the prefrontal cortex still remains poorly understood. Only after 1970, the functions of the frontal lobes have been conceptualized from different points of view (behaviorism, cognitivism). Recently,different parallel circuits connecting discrete cortical and subcortical regions of the frontal lobes have been described. Three of these circuits are the most relevant to understanding of behavior: the dorsolateral prefrontal circuit, that mediates executive behavior; the orbitofrontal prefrontal circuit, mediating social behavior, and the medial frontal circuit, involved in motivation. Damage to the frontal cortex impairs planning, problem solving, reasoning, concept formation, temporal ordering of stimuli, estimation, attention, memory search, maintaining information in working memory, associative learning,certain forms of skilled motor activities, image generation and manipulation of the spatial properties of a stimulus, metacognitive thinking, and social cognition. Several theories have been proposed to explain the functions of the prefrontal cortex. Currently,the most influential cognitive models are: the Norman and Shallice supervisory attentional system, involved in non-routine selection; the Baddeley working memory model with the central executive as a supervisory controlling system, in which impairment leads to a 'dysexecutive syndrome'; and the Grafman's model of managerial knowledge units, stored as macrostructured information in the frontal cortex. The prefrontal cortex is essential for attentional control, manipulation of stored knowledge and modulation of complex actions, cognition, emotion and behavior.

  9. Voltage-sensitive dye imaging reveals shifting spatiotemporal spread of whisker-induced activity in rat barrel cortex.

    Science.gov (United States)

    Lustig, Brian R; Friedman, Robert M; Winberry, Jeremy E; Ebner, Ford F; Roe, Anna W

    2013-05-01

    In rats, navigating through an environment requires continuous information about objects near the head. Sensory information such as object location and surface texture are encoded by spike firing patterns of single neurons within rat barrel cortex. Although there are many studies using single-unit electrophysiology, much less is known regarding the spatiotemporal pattern of activity of populations of neurons in barrel cortex in response to whisker stimulation. To examine cortical response at the population level, we used voltage-sensitive dye (VSD) imaging to examine ensemble spatiotemporal dynamics of barrel cortex in response to stimulation of single or two adjacent whiskers in urethane-anesthetized rats. Single whisker stimulation produced a poststimulus fluorescence response peak within 12-16 ms in the barrel corresponding to the stimulated whisker (principal whisker). This fluorescence subsequently propagated throughout the barrel field, spreading anisotropically preferentially along a barrel row. After paired whisker stimulation, the VSD signal showed sublinear summation (less than the sum of 2 single whisker stimulations), consistent with previous electrophysiological and imaging studies. Surprisingly, we observed a spatial shift in the center of activation occurring over a 10- to 20-ms period with shift magnitudes of 1-2 barrels. This shift occurred predominantly in the posteromedial direction within the barrel field. Our data thus reveal previously unreported spatiotemporal patterns of barrel cortex activation. We suggest that this nontopographical shift is consistent with known functional and anatomic asymmetries in barrel cortex and that it may provide an important insight for understanding barrel field activation during whisking behavior.

  10. Lesions to the Orbitofrontal Cortex Produce the Novelty-Seeking Behavior Deficits in Rats%大鼠眶额叶皮质受损破坏新异性探索行为

    Institute of Scientific and Technical Information of China (English)

    王秀松; 付玉; 马漫修; 张俊俊; 马原野

    2009-01-01

    利用旷场测试和Y-迷宫测试两种行为模型检测了双侧眶额叶(orbitofrontal cortex,OFC)电损伤或假损伤雄性SD大鼠的新异性探索行为,探讨YOFC在大鼠探索新异环境中的作用.旷场测试的结果发现,OFC损伤大鼠的行走距离和直立次数较假损组有明显降低;同时,在Y-迷宫测试中与假损伤组大鼠相比,OFC损伤大鼠在新异臂的访问时间和穿梭次数明显降低.提示眶额叶皮质在大鼠新异性探索行为中起着重要作用.

  11. Antenatal betamethasone produces protracted changes in anxiety-like behaviors and in the expression of microtubule-associated protein 2, brain-derived neurotrophic factor and the tyrosine kinase B receptor in the rat cerebellar cortex.

    Science.gov (United States)

    Pascual, Rodrigo; Valencia, Martina; Bustamante, Carlos

    2015-06-01

    Using classic Golgi staining methods, we previously showed that the administration of synthetic glucocorticoid betamethasone in equivalent doses to those given in cases of human premature birth generates long-term alterations in Purkinje cell dendritic development in the cerebellar cortex. In the present study, we evaluated whether betamethasone alters the immunohistochemical expression of proteins that participate in cerebellar Purkinje cell dendritic development and maintenance, including microtubule-associated protein 2 (MAP2), brain-derived neurotrophic factor (BDNF) and the tyrosine kinase B receptor (TrkB), which are located predominantly in the cerebellar molecular layer where Purkinje cell dendritogenesis occurs. Consistent with our previous Golgi stain studies, we observed that animals prenatally exposed to a single course of betamethasone showed long-term alterations in the expression of MAP2, BDNF and TrkB. Additionally, these protracted molecular changes were accompanied by anxiety-like behaviors in the elevated plus maze and marble burying tests.

  12. Risk factors and spatial distribution of extended spectrum β-lactamase-producing- Escherichia coli at retail poultry meat markets in Malaysia: a cross-sectional study

    National Research Council Canada - National Science Library

    Aliyu, A B; Saleha, A A; Jalila, A; Zunita, Z

    2016-01-01

    .... Hence, the objective of this study was to determine the prevalence, spatial distribution and potential risk factors associated with the dissemination of ESBL-EC in poultry meat retail at wet-markets...

  13. Primary Auditory Cortex Regulates Threat Memory Specificity

    Science.gov (United States)

    Wigestrand, Mattis B.; Schiff, Hillary C.; Fyhn, Marianne; LeDoux, Joseph E.; Sears, Robert M.

    2017-01-01

    Distinguishing threatening from nonthreatening stimuli is essential for survival and stimulus generalization is a hallmark of anxiety disorders. While auditory threat learning produces long-lasting plasticity in primary auditory cortex (Au1), it is not clear whether such Au1 plasticity regulates memory specificity or generalization. We used…

  14. Primary Auditory Cortex Regulates Threat Memory Specificity

    Science.gov (United States)

    Wigestrand, Mattis B.; Schiff, Hillary C.; Fyhn, Marianne; LeDoux, Joseph E.; Sears, Robert M.

    2017-01-01

    Distinguishing threatening from nonthreatening stimuli is essential for survival and stimulus generalization is a hallmark of anxiety disorders. While auditory threat learning produces long-lasting plasticity in primary auditory cortex (Au1), it is not clear whether such Au1 plasticity regulates memory specificity or generalization. We used…

  15. Spatial imagery relies on a sensory independent, though sensory sensitive, functional organization within the parietal cortex: a fMRI study of angle discrimination in sighted and congenitally blind individuals.

    Science.gov (United States)

    Bonino, Daniela; Ricciardi, Emiliano; Bernardi, Giulio; Sani, Lorenzo; Gentili, Claudio; Vecchi, Tomaso; Pietrini, Pietro

    2015-02-01

    Although vision offers distinctive information to space representation, individuals who lack vision since birth often show perceptual and representational skills comparable to those found in sighted individuals. However, congenitally blind individuals may result in impaired spatial analysis, when engaging in 'visual' spatial features (e.g., perspective or angle representation) or complex spatial mental abilities. In the present study, we measured behavioral and brain responses using functional magnetic resonance imaging in sighted and congenitally blind individuals during spatial imagery based on a modified version of the mental clock task (e.g., angle discrimination) and a simple recognition control condition, as conveyed across distinct sensory modalities: visual (sighted individuals only), tactile and auditory. Blind individuals were significantly less accurate during the auditory task, but comparable-to-sighted during the tactile task. As expected, both groups showed common neural activations in intraparietal and superior parietal regions across visual and non-visual spatial perception and imagery conditions, indicating the more abstract, sensory independent functional organization of these cortical areas, a property that we named supramodality. At the same time, however, comparisons in brain responses and functional connectivity patterns across experimental conditions demonstrated also a functional lateralization, in a way that correlated with the distinct behavioral performance in blind and sighted individuals. Specifically, blind individuals relied more on right parietal regions, mainly in the tactile and less in the auditory spatial processing. In sighted, spatial representation across modalities relied more on left parietal regions. In conclusions, intraparietal and superior parietal regions subserve supramodal spatial representations in sighted and congenitally blind individuals. Differences in their recruitment across non-visual spatial processing in

  16. The spatial-temporal interaction in the LTP induction between layer IV to layer II/III and layer II/III to layer II/III connections in rats' visual cortex during the development.

    Science.gov (United States)

    Li, Da-Ke; Zhang, Chao; Gu, Yu; Zhang, She-Hong; Shi, Jian; Chen, Xian-Hua

    2017-03-20

    During the early developmental period, long-term potentiation (LTP) can be induced in both vertical and horizontal connections in the rat visual cortex. However, the temporal difference in LTP change between the two pathways during animal development remains unclear. In this study, LTP in vertical (from layer IV to layer II/III) and horizontal (from layer II/III to layer II/III) synaptic connections were recorded in brain slices from the same rats, and the developmental changes of LTP in both directions were compared within the animals' eye-opening period. The results showed that the LTP amplitudes declined to unobservable levels on P16 in the horizontal connections and on P20 in the vertical synaptic connections. Meanwhile, V-LTP (LTP induced in the vertical direction) was always stronger than H-LTP (LTP induced in the horizontal direction) under the same conditions of pairing stimulus (PS). Next, H-LTP and V-LTP were induced from the same neuron in layer II/III to determine the spatiotemporal interactions between layer II/III horizontal inputs and ascending synaptic inputs during the maturation of rat visual cortex. The data show that the weak PS, which failed to induce H-LTP alone, was able to induce H-LTP effectively while V-LTP was performed on P10. Our results suggest that V-LTP can strengthen H-LTP induction in the visual cortex during the early developmental period. In contrast, the regulatory effect of H-LTP on V-LTP was much weaker.

  17. Spontaneous pattern formation and pinning in the visual cortex

    Science.gov (United States)

    Baker, Tanya I.

    Bifurcation theory and perturbation theory can be combined with a knowledge of the underlying circuitry of the visual cortex to produce an elegant story explaining the phenomenon of visual hallucinations. A key insight is the application of an important set of ideas concerning spontaneous pattern formation introduced by Turing in 1952. The basic mechanism is a diffusion driven linear instability favoring a particular wavelength that determines the size of the ensuing stripe or spot periodicity of the emerging spatial pattern. Competition between short range excitation and longer range inhibition in the connectivity profile of cortical neurons provides the difference in diffusion length scales necessary for the Turing mechanism to occur and has been proven by Ermentrout and Cowan to be sufficient to explain the generation of a subset of reported geometric hallucinations. Incorporating further details of the cortical circuitry, namely that neurons are also weakly connected to other neurons sharing a particular stimulus orientation or spatial frequency preference at even longer ranges and the resulting shift-twist symmetry of the neuronal connectivity, improves the story. We expand this approach in order to be able to include the tuned responses of cortical neurons to additional visual stimulus features such as motion, color and disparity. We apply a study of nonlinear dynamics similar to the analysis of wave propagation in a crystalline lattice to demonstrate how a spatial pattern formed through the Turing instability can be pinned to the geometric layout of various feature preferences. The perturbation analysis is analogous to solving the Schrodinger equation in a weak periodic potential. Competition between the local isotropic connections which produce patterns of activity via the Turing mechanism and the weaker patchy lateral connections that depend on a neuron's particular set of feature preferences create long wavelength affects analogous to commensurate

  18. Motion-defined surface segregation in human visual cortex.

    Science.gov (United States)

    Vigano, Gabriel J; Maloney, Ryan T; Clifford, Colin W G

    2014-11-01

    Surface segregation provides an efficient way to parse the visual scene for perceptual analysis. Here, we investigated the segregation of a bivectorial motion display into transparent surfaces through a psychophysical task and fMRI. We found that perceptual transparency correlated with neural activity in the early areas of the visual cortex, suggesting these areas may be involved in the segregation of motion-defined surfaces. Two oppositely rotating, uniquely colored random dot kinematograms (RDKs) were presented either sequentially or in a spatially interleaved manner, displayed at varying alternation frequencies. Participants reported the color and rotation direction pairing of the RDKs in the psychophysical task. The spatially interleaved display generated the percept of motion transparency across the range of frequencies tested, yielding ceiling task performance. At high alternation frequencies, performance on the sequential display also approached ceiling, indicative of perceived transparency. However, transparency broke down in lower alternation frequency sequential displays, producing performance close to chance. A corresponding pattern mirroring the psychophysical data was also evident in univariate and multivariate analyses of the fMRI BOLD activity in visual cortical areas V1, V2, V3, V3AB, hV4, and V5/MT+. Using gray RDKs, we found significant presentation by frequency interactions in most areas; differences in BOLD signal between presentation types were significant only at the lower alternation frequency. Multivariate pattern classification was similarly unable to discriminate between presentation types at the higher frequency. This study provides evidence that early visual cortex may code for motion-defined surface segregation, which in turn may enable perceptual transparency.

  19. Working Memory in the Prefrontal Cortex

    Directory of Open Access Journals (Sweden)

    Shintaro Funahashi

    2017-04-01

    Full Text Available The prefrontal cortex participates in a variety of higher cognitive functions. The concept of working memory is now widely used to understand prefrontal functions. Neurophysiological studies have revealed that stimulus-selective delay-period activity is a neural correlate of the mechanism for temporarily maintaining information in working memory processes. The central executive, which is the master component of Baddeley’s working memory model and is thought to be a function of the prefrontal cortex, controls the performance of other components by allocating a limited capacity of memory resource to each component based on its demand. Recent neurophysiological studies have attempted to reveal how prefrontal neurons achieve the functions of the central executive. For example, the neural mechanisms of memory control have been examined using the interference effect in a dual-task paradigm. It has been shown that this interference effect is caused by the competitive and overloaded recruitment of overlapping neural populations in the prefrontal cortex by two concurrent tasks and that the information-processing capacity of a single neuron is limited to a fixed level, can be flexibly allocated or reallocated between two concurrent tasks based on their needs, and enhances behavioral performance when its allocation to one task is increased. Further, a metamemory task requiring spatial information has been used to understand the neural mechanism for monitoring its own operations, and it has been shown that monitoring the quality of spatial information represented by prefrontal activity is an important factor in the subject's choice and that the strength of spatially selective delay-period activity reflects confidence in decision-making. Although further studies are needed to elucidate how the prefrontal cortex controls memory resource and supervises other systems, some important mechanisms related to the central executive have been identified.

  20. Processing of sound location in human cortex.

    Science.gov (United States)

    Lewald, Jörg; Riederer, Klaus A J; Lentz, Tobias; Meister, Ingo G

    2008-03-01

    This functional magnetic resonance imaging study was focused on the neural substrates underlying human auditory space perception. In order to present natural-like sound locations to the subjects, acoustic stimuli convolved with individual head-related transfer functions were used. Activation foci, as revealed by analyses of contrasts and interactions between sound locations, formed a complex network, including anterior and posterior regions of temporal lobe, posterior parietal cortex, dorsolateral prefrontal cortex and inferior frontal cortex. The distinct topography of this network was the result of different patterns of activation and deactivation, depending on sound location, in the respective voxels. These patterns suggested different levels of complexity in processing of auditory spatial information, starting with simple left/right discrimination in the regions surrounding the primary auditory cortex, while the integration of information on hemispace and eccentricity of sound may take place at later stages. Activations were identified as being located in regions assigned to both the dorsal and ventral auditory cortical streams, that are assumed to be preferably concerned with analysis of spatial and non-spatial sound features, respectively. The finding of activations also in the ventral stream could, on the one hand, reflect the well-known functional duality of auditory spectral analysis, that is, the concurrent extraction of information based on location (due to the spectrotemporal distortions caused by head and pinnae) and spectral characteristics of a sound source. On the other hand, this result may suggest the existence of shared neural networks, performing analyses of auditory 'higher-order' cues for both localization and identification of sound sources.

  1. Pinwheel-dipole configuration in cat early visual cortex.

    Science.gov (United States)

    Ribot, Jérôme; Romagnoni, Alberto; Milleret, Chantal; Bennequin, Daniel; Touboul, Jonathan

    2016-03-01

    In the early visual cortex, information is processed within functional maps whose layouts are thought to underlie visual perception. However, the precise organization of these functional maps as well as their interrelationships remain unsettled. Here, we show that spatial frequency representation in cat early visual cortex exhibits singularities around which the map organizes like an electric dipole potential. These singularities are precisely co-located with singularities of the orientation map: the pinwheel centers. To show this, we used high resolution intrinsic optical imaging in cat areas 17 and 18. First, we show that a majority of pinwheel centers exhibit in their neighborhood both semi-global maximum and minimum in the spatial frequency map (i.e. extreme values of the spatial frequency in a hypercolumn). This contradicts pioneering studies suggesting that pinwheel centers are placed at the locus of a single spatial frequency extremum. Based on an analogy with electromagnetism, we proposed a mathematical model for a dipolar structure, accurately fitting optical imaging data. We conclude that a majority of orientation pinwheel centers form spatial frequency dipoles in cat early visual cortex. Given the functional specificities of neurons at singularities in the visual cortex, it is argued that the dipolar organization of spatial frequency around pinwheel centers could be fundamental for visual processing.

  2. A Climatology of Derecho-Producing Mesoscale Convective Systems in the Central and Eastern United States, 1986-95. Part I: Temporal and Spatial Distribution.

    Science.gov (United States)

    Bentley, Mace L.; Mote, Thomas L.

    1998-11-01

    In 1888, Iowa weather researcher Gustavus Hinrichs gave widespread convectively induced windstorms the name "derecho". Refinements to this definition have evolved after numerous investigations of these systems; however, to date, a derecho climatology has not been conducted.This investigation examines spatial and temporal aspects of derechos and their associated mesoscale convective systems that occurred from 1986 to 1995. The spatial distribution of derechos revealed four activity corridors during the summer, five during the spring, and two during the cool season. Evidence suggests that the primary warm season derecho corridor is located in the southern Great Plains. During the cool season, derecho activity was found to occur in the southeast states and along the Atlantic seaboard. Temporally, derechos are primarily late evening or overnight events during the warm season and are more evenly distributed throughout the day during the cool season.

  3. Spatially resolved Thomson scattering measurements of the transition from the collective to the non-collective regime in a laser-produced plasma

    Science.gov (United States)

    Schaeffer, D. B.; Constantin, C. G.; Bondarenko, A. S.; Everson, E. T.; Niemann, C.

    2016-11-01

    We present optical Thomson scattering results that image for the first time in a single measurement the spatial transition from collective to non-collective scattering. Data were taken in the Phoenix laser laboratory at the University of California, Los Angeles. The Raptor laser was used to ablate a carbon plasma, which was diagnosed with the frequency-doubled Phoenix laser serving as a Thomson scattering probe. Scattered light was collected from the laser plasma up to 10 cm from the target surface and up to 10 us after ablation, and imaged with high spatial and spectral resolutions. The results show a strong Thomson collective feature close to the target surface that smoothly transitions to a non-collective feature over several mm.

  4. Distance modulation of neural activity in the visual cortex.

    Science.gov (United States)

    Dobbins, A C; Jeo, R M; Fiser, J; Allman, J M

    1998-07-24

    Humans use distance information to scale the size of objects. Earlier studies demonstrated changes in neural response as a function of gaze direction and gaze distance in the dorsal visual cortical pathway to parietal cortex. These findings have been interpreted as evidence of the parietal pathway's role in spatial representation. Here, distance-dependent changes in neural response were also found to be common in neurons in the ventral pathway leading to inferotemporal cortex of monkeys. This result implies that the information necessary for object and spatial scaling is common to all visual cortical areas.

  5. [Neuroanatomy of Frontal Association Cortex].

    Science.gov (United States)

    Takada, Masahiko

    2016-11-01

    The frontal association cortex is composed of the prefrontal cortex and the motor-related areas except the primary motor cortex (i.e., the so-called higher motor areas), and is well-developed in primates, including humans. The prefrontal cortex receives and integrates large bits of diverse information from the parietal, temporal, and occipital association cortical areas (termed the posterior association cortex), and paralimbic association cortical areas. This information is then transmitted to the primary motor cortex via multiple motor-related areas. Given these facts, it is likely that the prefrontal cortex exerts executive functions for behavioral control. The functional input pathways from the posterior and paralimbic association cortical areas to the prefrontal cortex are classified primarily into six groups. Cognitive signals derived from the prefrontal cortex are conveyed to the rostral motor-related areas to transform them into motor signals, which finally enter the primary motor cortex via the caudal motor-related areas. Furthermore, it has been shown that, similar to the primary motor cortex, areas of the frontal association cortex form individual networks (known as "loop circuits") with the basal ganglia and cerebellum via the thalamus, and hence are extensively involved in the expression and control of behavioral actions.

  6. Rapid Eye Movement Sleep deprivation produces long-term detrimental effects in spatial memory and modifies the cellular composition of the subgranular zone

    Directory of Open Access Journals (Sweden)

    Sofia eSoto-Rodriguez

    2016-05-01

    Full Text Available Sleep deprivation (SD affects spatial memory and proliferation in the dentate gyrus. It is unknown whether these deleterious effects persist in the long run. The aim of this study was to evaluate the proliferation, differentiation and maturation of neural progenitors as well as spatial memory 21 days after suffering sleep deprivation. Sixty-day old male Balb/C mice were exposed to 72-h REM-SD. Spatial memory, cell fate, apoptosis and expression levels of insulin-like growth factor 1 receptor (IGF-1R were evaluated in the hippocampus at 0, 14 and 21 days after SD or control conditions. After 21-d recovery period, memory performance was assessed with the Barnes maze, we found a significant memory impairment in SD mice vs. control (94.0 ± 10.2s vs. 25.2 ± 4.5s; p < 0.001. The number of BrdU+ cells was significantly decreased in the SD groups at day 14 (controls = 1.6 ± 0.1 vs. SD mice = 1.2 ± 0.1 cells/field; p=0.001 and at day 21 (controls = 0.2 ± 0.03 vs. SD mice = 0.1 ± 0.02 cells/field; p < 0.001. A statistically significant decrease was observed in neuronal differentiation (1.4 ± 0.1 cells/field vs. 0.9 ± 0.1 cells/field, p = 0.003. Apoptosis was significantly increased at day 14 after SD (0.53 ± 0.06 TUNEL+ cells/field compared to controls (0.19 ± 0.03 TUNEL+ cells/field p<0.001 and at 21-d after SD (SD mice 0.53±0.15 TUNEL+ cells/field; p = 0.035. At day 0, IGF-1R expression showed a statistically significant reduction in SD animals (64.6 ± 12.2 units when compared to the control group (102.0 ± 9.8 units; p = 0.043. However, no statistically significant differences were found at day 14 and 21 after SD. In conclusion, a single exposition to SD for 72-h can induce deleterious effects that persist for at least three weeks. These changes are characterized by spatial memory impairment, reduction in the number of hippocampal BrdU+ cells and persistent apoptosis rate. In contrast, changes IGF-1R expression appears to be a transient

  7. Functional topography of a distributed neural system for spatial and nonspatial information maintenance in working memory.

    Science.gov (United States)

    Sala, Joseph B; Rämä, Pia; Courtney, Susan M

    2003-01-01

    We investigated the degree to which the distributed and overlapping patterns of activity for working memory (WM) maintenance of objects and spatial locations are functionally dissociable. Previous studies of the neural system responsible for maintenance of different types of information in WM have reported seemingly contradictory results concerning the degree to which spatial and nonspatial information maintenance leads to distinct patterns of activation in prefrontal cortex. These inconsistent results may be partly attributable to the fact that different types of objects were used for the "object WM task" across studies. In the current study, we directly compared the patterns of response during WM tasks for face identity, house identity, and spatial location using functional magnetic resonance imaging (fMRI). Furthermore, independence of the neural resources available for spatial and object WM was tested behaviorally using a dual-task paradigm. Together, these results suggest that the mechanisms for the maintenance of house identity information are distributed and overlapping with those that maintain spatial location information, while the mechanisms for maintenance of face identity information are relatively more independent. There is, however, a consistent functional topography that results in superior prefrontal cortex producing the greatest response during spatial WM tasks, and middle and inferior prefrontal cortices producing their greatest responses during object WM tasks, independent of the object type. These results argue for a dorsal-ventral functional organization for spatial and nonspatial information. However, objects may contain both spatial and nonspatial information and, thus, have a distributed but not equipotent representation across both dorsal and ventral prefrontal cortex.

  8. The discovery of motor cortex and its background.

    Science.gov (United States)

    Gross, Charles G

    2007-01-01

    In 1870 Gustav Fritsch and Edvard Hitzig showed that electrical stimulation of the cerebral cortex of a dog produced movements. This was a crucial event in the development of modern neuroscience because it was the first good experimental evidence for a) cerebral cortex involvement in motor function, b) the electrical excitability of the cortex, c) topographic representation in the brain, and d) localization of function in different regions of the cerebral cortex. This paper discusses their experiment and some developments in the previous two centuries that led to it including the ideas of Thomas Willis and Emanuel Swedenborg, the widespread interest in electricity and the localizations of function of Franz Joseph Gall, John Hughlings Jackson, and Paul Broca. We also consider the subsequent study of the motor cortex by David Ferrier and others.

  9. Gaining the upper hand: comparison of alphabetic and keyboard positions as spatial features of letters producing distinct S-R compatibility effects.

    Science.gov (United States)

    Kozlik, Julia; Neumann, Roland

    2013-09-01

    The present study explored which stimulus feature, alphabetic or keyboard position, primarily influences letter processing in different task settings. In Experiment 1 (alphabetic position judgment) a response side effect (faster responses when the location of letters within the alphabet or on the keyboard maps onto the response hand) could be observed for alphabetic position as task-relevant stimulus feature. In Experiments 2 and 3 participants responded to a non-spatial stimulus feature (uppercase-lowercase classification) so that both attributes can be characterized as task-irrelevant. The pattern indicated that a keyboard position-hand correspondence effect emerged independent of the time window (after stimulus onset) in which the response was given. However, an alphabetic position-hand correspondence effect only emerged when participants were forced to delay their responses by 450ms. The overall pattern indicated that although both features were processed and translated into a spatial code reflecting their position within the alphabet vs. on the keyboard, the relevance of these features to the task as well as the time that elapsed since stimulus onset determined which attribute of the letters was effective in yielding a stimulus-response compatibility effect.

  10. Rapid Eye Movement Sleep Deprivation Produces Long-Term Detrimental Effects in Spatial Memory and Modifies the Cellular Composition of the Subgranular Zone

    Science.gov (United States)

    Soto-Rodriguez, Sofia; Lopez-Armas, Gabriela; Luquin, Sonia; Ramos-Zuñiga, Rodrigo; Jauregui-Huerta, Fernando; Gonzalez-Perez, Oscar; Gonzalez-Castañeda, Rocio E.

    2016-01-01

    Sleep deprivation (SD) affects spatial memory and proliferation in the dentate gyrus. It is unknown whether these deleterious effects persist in the long run. The aim of this study was to evaluate the proliferation, differentiation and maturation of neural progenitors as well as spatial memory 21 days after suffering SD. Sixty-day old male Balb/C mice were exposed to 72-h REM-SD. Spatial memory, cell fate, apoptosis and expression levels of insulin-like growth factor 1 receptor (IGF-1R) were evaluated in the hippocampus at 0, 14, and 21 days after SD or control conditions. After 21-days recovery period, memory performance was assessed with the Barnes maze, we found a significant memory impairment in SD mice vs. control (94.0 ± 10.2 s vs. 25.2 ± 4.5 s; p < 0.001). The number of BrdU+ cells was significantly decreased in the SD groups at day 14 (controls = 1.6 ± 0.1 vs. SD mice = 1.2 ± 0.1 cells/field; p = 0.001) and at day 21 (controls = 0.2 ± 0.03 vs. SD mice = 0.1 ± 0.02 cells/field; p < 0.001). A statistically significant decrease was observed in neuronal differentiation (1.4 ± 0.1 cells/field vs. 0.9 ± 0.1 cells/field, p = 0.003). Apoptosis was significantly increased at day 14 after SD (0.53 ± 0.06 TUNEL+ cells/field) compared to controls (0.19 ± 0.03 TUNEL+ cells/field p < 0.001) and at 21-days after SD (SD mice 0.53 ± 0.15 TUNEL+ cells/field; p = 0.035). At day 0, IGF-1R expression showed a statistically significant reduction in SD animals (64.6 ± 12.2 units) when compared to the control group (102.0 ± 9.8 units; p = 0.043). However, no statistically significant differences were found at days 14 and 21 after SD. In conclusion, a single exposition to SD for 72-h can induce deleterious effects that persist for at least 3 weeks. These changes are characterized by spatial memory impairment, reduction in the number of hippocampal BrdU+ cells and persistent apoptosis rate. In contrast, changes IGF-1R expression appears to be a transient event

  11. Monkey cortex through fMRI glasses.

    Science.gov (United States)

    Vanduffel, Wim; Zhu, Qi; Orban, Guy A

    2014-08-06

    In 1998 several groups reported the feasibility of fMRI experiments in monkeys, with the goal to bridge the gap between invasive nonhuman primate studies and human functional imaging. These studies yielded critical insights in the neuronal underpinnings of the BOLD signal. Furthermore, the technology has been successful in guiding electrophysiological recordings and identifying focal perturbation targets. Finally, invaluable information was obtained concerning human brain evolution. We here provide a comprehensive overview of awake monkey fMRI studies mainly confined to the visual system. We review the latest insights about the topographic organization of monkey visual cortex and discuss the spatial relationships between retinotopy and category- and feature-selective clusters. We briefly discuss the functional layout of parietal and frontal cortex and continue with a summary of some fascinating functional and effective connectivity studies. Finally, we review recent comparative fMRI experiments and speculate about the future of nonhuman primate imaging.

  12. Regulating prefrontal cortex activation

    DEFF Research Database (Denmark)

    Aznar, Susana; Klein, Anders Bue

    2013-01-01

    of emotion-based actions, such as addiction and other impulse-related behaviors. In this review, we give an overview of the 5-HT2A receptor distribution (neuronal, intracellular, and anatomical) along with its functional and physiological effect on PFC activation, and how that relates to more recent findings......The prefrontal cortex (PFC) is involved in mediating important higher-order cognitive processes such as decision making, prompting thereby our actions. At the same time, PFC activation is strongly influenced by emotional reactions through its functional interaction with the amygdala...... is highly expressed in the prefrontal cortex areas, playing an important role in modulating cortical activity and neural oscillations (brain waves). This makes it an interesting potential pharmacological target for the treatment of neuropsychiatric modes characterized by lack of inhibitory control...

  13. Visual map shifts based on whisker-guided cues in the young mouse visual cortex.

    Science.gov (United States)

    Yoshitake, Kohei; Tsukano, Hiroaki; Tohmi, Manavu; Komagata, Seiji; Hishida, Ryuichi; Yagi, Takeshi; Shibuki, Katsuei

    2013-12-12

    Mice navigate nearby space using their vision and whiskers, and young mice learn to integrate these heterogeneous inputs in perceptual space. We found that cortical responses were depressed in the primary visual cortex of young mice after wearing a monocular prism. This depression was uniformly observed in the primary visual cortex and was eliminated by whisker trimming or lesions in the posterior parietal cortex. Compensatory visual map shifts of responses elicited via the eye that had worn the prism were also observed. As a result, cortical responses elicited via each eye were clearly separated when a visual stimulus was placed in front of the mice. A comparison of response areas before and after prism wearing indicated that the map shifts were produced by depression with spatial eccentricity. Visual map shifts based on whisker-guided cues may serve as a model for investigating the cellular and molecular mechanisms underlying higher sensory integration in the mammalian brain. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

  14. Spontaneous activity in the piriform cortex extends the dynamic range of cortical odor coding.

    Science.gov (United States)

    Tantirigama, Malinda L S; Huang, Helena H-Y; Bekkers, John M

    2017-02-28

    Neurons in the neocortex exhibit spontaneous spiking activity in the absence of external stimuli, but the origin and functions of this activity remain uncertain. Here, we show that spontaneous spiking is also prominent in a sensory paleocortex, the primary olfactory (piriform) cortex of mice. In the absence of applied odors, piriform neurons exhibit spontaneous firing at mean rates that vary systematically among neuronal classes. This activity requires the participation of NMDA receptors and is entirely driven by bottom-up spontaneous input from the olfactory bulb. Odor stimulation produces two types of spatially dispersed, odor-distinctive patterns of responses in piriform cortex layer 2 principal cells: Approximately 15% of cells are excited by odor, and another approximately 15% have their spontaneous activity suppressed. Our results show that, by allowing odor-evoked suppression as well as excitation, the responsiveness of piriform neurons is at least twofold less sparse than currently believed. Hence, by enabling bidirectional changes in spiking around an elevated baseline, spontaneous activity in the piriform cortex extends the dynamic range of odor representation and enriches the coding space for the representation of complex olfactory stimuli.

  15. Nonuniform isotope patterns produced by collision-induced dissociation of homogeneously labeled ubiquitin: implications for spatially resolved hydrogen/deuterium exchange ESI-MS studies.

    Science.gov (United States)

    Ferguson, Peter L; Konermann, Lars

    2008-06-01

    There is an ongoing debate whether collision-induced dissociation (CID) of electrosprayed proteins after solution-phase hydrogen/deuterium exchange (HDX) is a viable approach for determining spatially resolved deuteration patterns. This work explores the use of two methods, source-CID and hexapole tandem mass spectrometry (MS/MS) on a quadrupole time-of-flight (Q-TOF) mass spectrometer, for measuring the fragment deuteration levels of regioselectively labeled ubiquitin. Both methods reveal that b-ions exhibit HDX levels significantly below that of the intact protein, whereas several y'' fragments are labeled to a much greater extent. These results are consistent with earlier source-CID data (Akashi, S.; Naito, Y.; Takio, K. Anal. Chem. 1999, 71, 4974-4980). However, the measured b-ion deuteration levels are in disagreement with the known solution-phase behavior of ubiquitin. Partial agreement is observed for y''-ions. Control experiments on homogeneously labeled ubiquitin (having the same average deuteration level at every exchangeable site) result in highly nonuniform fragment HDX levels. In particular, b-ions exhibit deuteration levels significantly below that of intact ubiquitin, thereby mimicking the behavior seen for the regioselectively labeled protein. This effect is likely caused by isotope fractionation during collisional activation, facilitated by the high mobility of charge carriers (scrambling) in the gas phase. The observation that the b-ion labeling behavior is largely independent of the spatial isotope distribution within solution-phase ubiquitin invalidates these ions as reporters of the protein deuteration pattern. This work questions the common practice of interpreting any nonuniformities in fragment deuteration as being indicative of regioselective solution-phase labeling. Artifactual deuterium enrichment or depletion during collisional activation may have contributed to the current lack of consensus as to whether HDX/CID represents a potentially

  16. Visual field map clusters in human frontoparietal cortex.

    Science.gov (United States)

    Mackey, Wayne E; Winawer, Jonathan; Curtis, Clayton E

    2017-06-19

    The visual neurosciences have made enormous progress in recent decades, in part because of the ability to drive visual areas by their sensory inputs, allowing researchers to define visual areas reliably across individuals and across species. Similar strategies for parcellating higher-order cortex have proven elusive. Here, using a novel experimental task and nonlinear population receptive field modeling, we map and characterize the topographic organization of several regions in human frontoparietal cortex. We discover representations of both polar angle and eccentricity that are organized into clusters, similar to visual cortex, where multiple gradients of polar angle of the contralateral visual field share a confluent fovea. This is striking because neural activity in frontoparietal cortex is believed to reflect higher-order cognitive functions rather than external sensory processing. Perhaps the spatial topography in frontoparietal cortex parallels the retinotopic organization of sensory cortex to enable an efficient interface between perception and higher-order cognitive processes. Critically, these visual maps constitute well-defined anatomical units that future studies of frontoparietal cortex can reliably target.

  17. Callosal agenesis and absence of primary visual cortex induced by prenatal X rays impair navigation's strategy and learning in tasks involving visuo-spatial working but not reference memory in mice.

    Science.gov (United States)

    Vitral, Renan Wesley Farinazzo; Vitral, Cristiani Moreira; Dutra, Marcelo Luiz

    2006-03-13

    This study was designed for the identification of possible and distinct abilities for behavioral recovery after prenatal cerebral damage. We adopted an interesting tool for promotion of cell's death. Due to the fact that neuroblastic cells and early postmitotic neurons on the beginning of differentiation are particularly sensible for the promotion of apoptosis, we used a low whole-body dose of X radiation on pregnant female mice on E16 (sixteenth gestational day) to promote damage on specific cerebral areas of the progeny, given that the pattern of cerebral neurogenesis is not homogeneous. The morphological results were previously described by our team. Here we noticed that the recovery of behavioral functions after prenatal damage seems to be related to specific factors of local cortical circuitry organization. The deficits found on visual navigation and working memory contrast with the recovery of primary visual functions and also with reference memory, where the mice have a delay on acquisition of learning but get it. As a conclusion we reasoning that changes on laminar organization on frontal cortex as well as the inter hemispheric cortical integration through the corpus callosum could promote relatively fixed cognitive dysfunctions, as those observed on performances that require strategies for navigation (decision making) and working memory, with consequences also observed on the subsequent learning.

  18. Recurrent circuitry dynamically shapes the activation of piriform cortex.

    Science.gov (United States)

    Franks, Kevin M; Russo, Marco J; Sosulski, Dara L; Mulligan, Abigail A; Siegelbaum, Steven A; Axel, Richard

    2011-10-06

    In the piriform cortex, individual odorants activate a unique ensemble of neurons that are distributed without discernable spatial order. Piriform neurons receive convergent excitatory inputs from random collections of olfactory bulb glomeruli. Pyramidal cells also make extensive recurrent connections with other excitatory and inhibitory neurons. We introduced channelrhodopsin into the piriform cortex to characterize these intrinsic circuits and to examine their contribution to activity driven by afferent bulbar inputs. We demonstrated that individual pyramidal cells are sparsely interconnected by thousands of excitatory synaptic connections that extend, largely undiminished, across the piriform cortex, forming a large excitatory network that can dominate the bulbar input. Pyramidal cells also activate inhibitory interneurons that mediate strong, local feedback inhibition that scales with excitation. This recurrent network can enhance or suppress bulbar input, depending on whether the input arrives before or after the cortex is activated. This circuitry may shape the ensembles of piriform cells that encode odorant identity.

  19. Dysgranular Retrosplenial Cortex Lesions in Rats Disrupt Cross-Modal Object Recognition

    Science.gov (United States)

    Hindley, Emma L.; Nelson, Andrew J. D.; Aggleton, John P.; Vann, Seralynne D.

    2014-01-01

    The retrosplenial cortex supports navigation, with one role thought to be the integration of different spatial cue types. This hypothesis was extended by examining the integration of nonspatial cues. Rats with lesions in either the dysgranular subregion of retrosplenial cortex (area 30) or lesions in both the granular and dysgranular subregions…

  20. The Harmonic Organization of Auditory Cortex

    Directory of Open Access Journals (Sweden)

    Xiaoqin eWang

    2013-12-01

    Full Text Available A fundamental structure of sounds encountered in the natural environment is the harmonicity. Harmonicity is an essential component of music found in all cultures. It is also a unique feature of vocal communication sounds such as human speech and animal vocalizations. Harmonics in sounds are produced by a variety of acoustic generators and reflectors in the natural environment, including vocal apparatuses of humans and animal species as well as music instruments of many types. We live in an acoustic world full of harmonicity. Given the widespread existence of the harmonicity in many aspects of the hearing environment, it is natural to expect that it be reflected in the evolution and development of the auditory systems of both humans and animals, in particular the auditory cortex. Recent neuroimaging and neurophysiology experiments have identified regions of non-primary auditory cortex in humans and non-human primates that have selective responses to harmonic pitches. Accumulating evidence has also shown that neurons in many regions of the auditory cortex exhibit characteristic responses to harmonically related frequencies beyond the range of pitch. Together, these findings suggest that a fundamental organizational principle of auditory cortex is based on the harmonicity. Such an organization likely plays an important role in music processing by the brain. It may also form the basis of the preference for particular classes of music and voice sounds.

  1. The neural correlates of spatial language in English and American Sign Language: a PET study with hearing bilinguals.

    Science.gov (United States)

    Emmorey, Karen; Grabowski, Thomas; McCullough, Stephen; Ponto, Laura L B; Hichwa, Richard D; Damasio, Hanna

    2005-02-01

    Rather than specifying spatial relations with a closed-class set of prepositions, American Sign Language (ASL) encodes spatial relations using space itself via classifier constructions. In these constructions, handshape morphemes specify object type, and the position of the hands in signing space schematically represents the spatial relation between objects. A [15O]water PET study was conducted to investigate the neural regions engaged during the production of English prepositions and ASL locative classifier constructions in hearing subjects with deaf parents (ASL-English bilinguals). Ten subjects viewed line drawings depicting a spatial relation between two objects and were asked to produce either an ASL locative classifier construction or an English preposition that described the spatial relation. The comparison task was to name the figure object (colored red) in either ASL or in English. Describing spatial relations in either ASL or English engaged parietal cortex bilaterally. However, an interaction analysis revealed that right superior parietal cortex was engaged to a greater extent for ASL than for English. We propose that right parietal cortex is involved in the visual-motoric transformation required for ASL. The production of both English prepositions and ASL nouns engaged Broca's area to a greater extent than ASL classifier constructions. We suggest that Broca's area is not engaged because these constructions do not involve retrieval of the name of an object or the name of a spatial relation. Finally, under the same task conditions, only left parietal activation was observed for monolingual English speakers producing spatial prepositions (H. Damasio et al., 2001, NeuroImage, 13). We conclude that the right hemisphere activation observed for ASL-English bilinguals was due to their life-long experience with spatial language in ASL.

  2. Preparatory attention in visual cortex.

    Science.gov (United States)

    Battistoni, Elisa; Stein, Timo; Peelen, Marius V

    2017-05-01

    Top-down attention is the mechanism that allows us to selectively process goal-relevant aspects of a scene while ignoring irrelevant aspects. A large body of research has characterized the effects of attention on neural activity evoked by a visual stimulus. However, attention also includes a preparatory phase before stimulus onset in which the attended dimension is internally represented. Here, we review neurophysiological, functional magnetic resonance imaging, magnetoencephalography, electroencephalography, and transcranial magnetic stimulation (TMS) studies investigating the neural basis of preparatory attention, both when attention is directed to a location in space and when it is directed to nonspatial stimulus attributes (content-based attention) ranging from low-level features to object categories. Results show that both spatial and content-based attention lead to increased baseline activity in neural populations that selectively code for the attended attribute. TMS studies provide evidence that this preparatory activity is causally related to subsequent attentional selection and behavioral performance. Attention thus acts by preactivating selective neurons in the visual cortex before stimulus onset. This appears to be a general mechanism that can operate on multiple levels of representation. We discuss the functional relevance of this mechanism, its limitations, and its relation to working memory, imagery, and expectation. We conclude by outlining open questions and future directions. © 2017 New York Academy of Sciences.

  3. 西安市生产者服务业空间布局特征与集聚模式研究%Spatial Features and Agglomeration of Producer Services in Xi'an City, China

    Institute of Scientific and Technical Information of China (English)

    薛东前; 石宁; 公晓晓

    2011-01-01

    以西安市为例,根据相关资料,采用定性与定量、静态与动态分析相结合的方法,借助ArcGIS软件,通过地理集中指数的测算,对西安市生产者服务业发展水平及其空间布局特征与集聚模式进行研究。主要结论:①生产者服务业具有一定专业化水平,集聚特征明显,产值和从业人数占第三产业的比重呈上升的趋势,但仍处于较低水平;②生产者服务业在城市内部空间集聚度偏低,但逐渐趋于集中,且分行业集聚程度参差不齐;③生产者服务业整体呈现多核心的集聚模式,分行业表现出不同的集聚模式类型;④空间结构形成机制主要是市场导向、区位因子、政府导向。对促进产业结构升级转换,确定合理的产业发展方向和城市产业规划、布局,加快西安市经济发展及提升城市竞争力都具有借鉴意义。%In the modern world, fast-growing producer service industry is gradually replacing manufacturing industry as a core force and innovation sources of economic growth in the metropolitan area and main force of urban spatial structure remodeling in western countries. In the context of economic restructuring and globalization, China's cities are facing with development chance of producer service, and the status of producer service in national economy will be enhanced. Xi'an, as the regional centre of Northwest China and the important financial and eco- nomic city in the western China, is the core city of Guanzhong-Tianshui economic region and important equip, ment manufacturing industry base. It has a predominant regional advantage. At present, urbanization of Xi'an turns into an accelerated stage, and the city enters into a quickly gathering term. According to the judgement index system of the regional economic growth stages, Xi'an is at the key transitional stage from the take-off stage of industrialization to maturity stage of industrialization

  4. Listening to Mozart enhances spatial-temporal reasoning: towards a neurophysiological basis.

    Science.gov (United States)

    Rauscher, F H; Shaw, G L; Ky, K N

    1995-02-06

    Motivated by predictions of a structured neuronal model of the cortex, we performed a behavioral experiment which showed that listening to a Mozart piano sonata produced significant short-term enhancement of spatial-temporal reasoning in college students. Here we present results from an experiment which replicates these findings, and shows that (i) 'repetitive' music does not enhance reasoning; (ii) a taped short story does not enhance reasoning; and (iii) short-term memory is not enhanced. We propose experiments designed to explore the neurophysiological bases of this causal enhancement of spatial-temporal reasoning by music, and begin to search for quantitative measures of further higher cognitive effects of music.

  5. The anterior cingulate cortex

    Directory of Open Access Journals (Sweden)

    Pavlović D.M.

    2009-01-01

    Full Text Available The anterior cingulate cortex (ACC has a role in attention, analysis of sensory information, error recognition, problem solving, detection of novelty, behavior, emotions, social relations, cognitive control, and regulation of visceral functions. This area is active whenever the individual feels some emotions, solves a problem, or analyzes the pros and cons of an action (if it is a right decision. Analogous areas are also found in higher mammals, especially whales, and they contain spindle neurons that enable complex social interactions. Disturbance of ACC activity is found in dementias, schizophrenia, depression, the obsessive-compulsive syndrome, and other neuropsychiatric diseases.

  6. Memoz - Spatial Weblogging

    Science.gov (United States)

    Hoem, Jon

    The article argues that spatial webpublishing has influence on weblogging, and calls for a revision of the current weblog definition. The weblog genre should be able to incorporate spatial representation, not only the sequential ordering of articles. The article show examples of different spatial forms, including material produced in Memoz (MEMory OrganiZer).

  7. Sensing with the Motor Cortex

    OpenAIRE

    Hatsopoulos, Nicholas G.; Suminski, Aaron J.

    2011-01-01

    The primary motor cortex is a critical node in the network of brain regions responsible for voluntary motor behavior. It has been less appreciated, however, that the motor cortex exhibits sensory responses in a variety of modalities including vision and somatosensation. We review current work that emphasizes the heterogeneity in sensori-motor responses in the motor cortex and focus on its implications for cortical control of movement as well as for brain-machine interface development.

  8. The Biology of Linguistic Expression Impacts Neural Correlates for Spatial Language

    Science.gov (United States)

    Emmorey, Karen; McCullough, Stephen; Mehta, Sonya; Ponto, Laura L. B.; Grabowski, Thomas J.

    2013-01-01

    Biological differences between signed and spoken languages may be most evident in the expression of spatial information. PET was used to investigate the neural substrates supporting the production of spatial language in American Sign Language as expressed by classifier constructions, in which handshape indicates object type and the location/motion of the hand iconically depicts the location/motion of a referent object. Deaf native signers performed a picture description task in which they overtly named objects or produced classifier constructions that varied in location, motion, or object type. In contrast to the expression of location and motion, the production of both lexical signs and object type classifier morphemes engaged left inferior frontal cortex and left inferior temporal cortex, supporting the hypothesis that unlike the location and motion components of a classifier construction, classifier handshapes are categorical morphemes that are retrieved via left hemisphere language regions. In addition, lexical signs engaged the anterior temporal lobes to a greater extent than classifier constructions, which we suggest reflects increased semantic processing required to name individual objects compared with simply indicating the type of object. Both location and motion classifier constructions engaged bilateral superior parietal cortex, with some evidence that the expression of static locations differentially engaged the left intraparietal sulcus. We argue that bilateral parietal activation reflects the biological underpinnings of sign language. To express spatial information, signers must transform visual–spatial representations into a body-centered reference frame and reach toward target locations within signing space. PMID:23249348

  9. Navigating actions through the rodent parietal cortex

    Directory of Open Access Journals (Sweden)

    Jonathan R. Whitlock

    2014-05-01

    Full Text Available The posterior parietal cortex (PPC participates in a manifold of cognitive functions, including visual attention, working memory, spatial processing and movement planning. Given the vast interconnectivity of PPC with sensory and motor areas, it is not surprising that neuronal recordings show that PPC often encodes mixtures of spatial information as well as the movements required to reach a goal. Recent work sought to discern the relative strength of spatial versus motor signaling in PPC by recording single unit activity in PPC of freely behaving rats during selective changes in either the spatial layout of the local environment or in the pattern of locomotor behaviors executed during navigational tasks. The results revealed unequivocally a predominant sensitivity of PPC neurons to locomotor action structure, with subsets of cells even encoding upcoming movements more than 1 second in advance. In light of these and other recent findings in the field, I propose that one of the key contributions of PPC to navigation is the synthesis of goal-directed behavioral sequences, and that the rodent PPC may serve as an apt system to investigate cellular mechanisms for spatial motor planning as traditionally studied in humans and monkeys.

  10. The effects of TMS over dorsolateral prefrontal cortex on trans-saccadic memory of multiple objects.

    Science.gov (United States)

    Tanaka, L L; Dessing, J C; Malik, P; Prime, S L; Crawford, J D

    2014-10-01

    Humans typically make several rapid eye movements (saccades) per second. It is thought that visual working memory can retain and spatially integrate three to four objects or features across each saccade but little is known about this neural mechanism. Previously we showed that transcranial magnetic stimulation (TMS) to the posterior parietal cortex and frontal eye fields degrade trans-saccadic memory of multiple object features (Prime, Vesia, & Crawford, 2008, Journal of Neuroscience, 28(27), 6938-6949; Prime, Vesia, & Crawford, 2010, Cerebral Cortex, 20(4), 759-772.). Here, we used a similar protocol to investigate whether dorsolateral prefrontal cortex (DLPFC), an area involved in spatial working memory, is also involved in trans-saccadic memory. Subjects were required to report changes in stimulus orientation with (saccade task) or without (fixation task) an eye movement in the intervening memory interval. We applied single-pulse TMS to left and right DLPFC during the memory delay, timed at three intervals to arrive approximately 100 ms before, 100 ms after, or at saccade onset. In the fixation task, left DLPFC TMS produced inconsistent results, whereas right DLPFC TMS disrupted performance at all three intervals (significantly for presaccadic TMS). In contrast, in the saccade task, TMS consistently facilitated performance (significantly for left DLPFC/perisaccadic TMS and right DLPFC/postsaccadic TMS) suggesting a dis-inhibition of trans-saccadic processing. These results are consistent with a neural circuit of trans-saccadic memory that overlaps and interacts with, but is partially separate from the circuit for visual working memory during sustained fixation.

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

    Directory of Open Access Journals (Sweden)

    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.

  12. Word Recognition in Auditory Cortex

    Science.gov (United States)

    DeWitt, Iain D. J.

    2013-01-01

    Although spoken word recognition is more fundamental to human communication than text recognition, knowledge of word-processing in auditory cortex is comparatively impoverished. This dissertation synthesizes current models of auditory cortex, models of cortical pattern recognition, models of single-word reading, results in phonetics and results in…

  13. Housing condition-related changes involved in reversal learning and its c-Fos associated activity in the prefrontal cortex.

    Science.gov (United States)

    Sampedro-Piquero, P; Zancada-Menendez, C; Begega, A

    2015-10-29

    Our study examined how different housing conditions modulated the acquisition of a spatial reference memory task and also, a reversal task in the 4-radial arm water maze (4-RAWM). The animals were randomly assigned to standard or enriched cages, and, as a type of complementary stimulation along with the environmental enrichment (EE), a group of rats also ran 15 min/day in a Rotarod. Elevated-zero maze results allowed us to discard that our exercise training increased anxiety-related behaviors. 4-RAWM results revealed that the non-enriched group had a worse performance during the acquisition and also, during the first trial of each session with respect to the enriched groups. Regarding the reversal task, this group made more perseverative errors in the previous platform position. Interestingly, we hardly found differences between the two enriched groups (with and without exercise). We also analyzed how the reversal learning, depending on the previous housing condition, modulated the expression of c-Fos-positive nuclei in different subdivisions of the medial prefrontal cortex (cingulate (Cg), prelimbic (PL) and infralimbic (IL) cortices) and in the orbitofrontal (OF) cortex. The enriched groups had higher c-Fos expression in the Cg and OF cortices and lower in the IL cortex respect to the non-enriched animals. In the PL cortex, we did not find significant differences between the groups that performed the reversal task. Therefore, our short EE protocol improved the performance in a spatial memory and a reversal task, whereas the exercise training, combined with the EE, did not produce a greater benefit. This better performance seemed to be related with the specific pattern of c-Fos expression in brain regions involved in cognitive flexibility.

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

    DEFF Research Database (Denmark)

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

    2011-01-01

    The adult visual cortex maintains a substantial potential for plasticity in response to a change in visual input. For instance, transcranial magnetic stimulation (TMS) studies have shown that binocular deprivation (BD) increases the cortical excitability for inducing phosphenes with TMS. Here, we...... employed TMS to trace plastic changes in adult visual cortex before, during, and after 48 h of monocular deprivation (MD) of the right dominant eye. In healthy adult volunteers, MD-induced changes in visual cortex excitability were probed with paired-pulse TMS applied to the left and right occipital cortex....... Stimulus–response curves were constructed by recording the intensity of the reported phosphenes evoked in the contralateral visual field at range of TMS intensities. Phosphene measurements revealed that MD produced a rapid and robust decrease in cortical excitability relative to a control condition without...

  15. Peripheral sounds rapidly activate visual cortex: evidence from electrocorticography.

    Science.gov (United States)

    Brang, David; Towle, Vernon L; Suzuki, Satoru; Hillyard, Steven A; Di Tusa, Senneca; Dai, Zhongtian; Tao, James; Wu, Shasha; Grabowecky, Marcia

    2015-11-01

    Neurophysiological studies with animals suggest that sounds modulate activity in primary visual cortex in the presence of concurrent visual stimulation. Noninvasive neuroimaging studies in humans have similarly shown that sounds modulate activity in visual areas even in the absence of visual stimuli or visual task demands. However, the spatial and temporal limitations of these noninvasive methods prevent the determination of how rapidly sounds activate early visual cortex and what information about the sounds is relayed there. Using spatially and temporally precise measures of local synaptic activity acquired from depth electrodes in humans, we demonstrate that peripherally presented sounds evoke activity in the anterior portion of the contralateral, but not ipsilateral, calcarine sulcus within 28 ms of sound onset. These results suggest that auditory stimuli rapidly evoke spatially specific activity in visual cortex even in the absence of concurrent visual stimulation or visual task demands. This rapid auditory-evoked activation of primary visual cortex is likely to be mediated by subcortical pathways or direct cortical projections from auditory to visual areas.

  16. Population coding of visual space: comparison of spatial representations in the dorsal and ventral pathways

    Directory of Open Access Journals (Sweden)

    Anne B Sereno

    2011-02-01

    Full Text Available Although the representation of space is as fundamental to visual processing as the representation of shape, it has received relatively little attention from neurophysiological investigations. In this study we characterize representations of space within visual cortex, and examine how they differ in a first direct comparison between dorsal and ventral subdivisions of the visual pathways. Neural activities were recorded in anterior inferotemporal cortex (AIT and lateral intraparietal cortex (LIP of awake behaving monkeys, structures associated with the ventral and dorsal visual pathways respectively, as a stimulus was presented at different locations within the visual field. In spatially selective cells, we find greater modulation of cell responses in LIP with changes in stimulus position. Further, using a novel population-based statistical approach (namely, multidimensional scaling, we recover the spatial map implicit within activities of neural populations, allowing us to quantitatively compare the geometry of neural space with physical space. We show that a population of spatially selective LIP neurons, despite having large receptive fields, is able to almost perfectly reconstruct stimulus locations within a low-dimensional representation. In contrast, a population of AIT neurons, despite each cell being spatially selective, provide less accurate low-dimensional reconstructions of stimulus locations. They produce instead only a topologically (categorically correct rendition of space, which nevertheless might be critical for object and scene recognition. Furthermore, we found that the spatial representation recovered from population activity shows greater translation invariance in LIP than in AIT. We suggest that LIP spatial representations may be dimensionally isomorphic with 3D physical space, while in AIT spatial representations may reflect a more categorical representation of space (e.g., next to or above.

  17. The orbitofrontal cortex and beyond: from affect to decision-making.

    Science.gov (United States)

    Rolls, Edmund T; Grabenhorst, Fabian

    2008-11-01

    The orbitofrontal cortex represents the reward or affective value of primary reinforcers including taste, touch, texture, and face expression. It learns to associate other stimuli with these to produce representations of the expected reward value for visual, auditory, and abstract stimuli including monetary reward value. The orbitofrontal cortex thus plays a key role in emotion, by representing the goals for action. The learning process is stimulus-reinforcer association learning. Negative reward prediction error neurons are related to this affective learning. Activations in the orbitofrontal cortex correlate with the subjective emotional experience of affective stimuli, and damage to the orbitofrontal cortex impairs emotion-related learning, emotional behaviour, and subjective affective state. With an origin from beyond the orbitofrontal cortex, top-down attention to affect modulates orbitofrontal cortex representations, and attention to intensity modulates representations in earlier cortical areas of the physical properties of stimuli. Top-down word-level cognitive inputs can bias affective representations in the orbitofrontal cortex, providing a mechanism for cognition to influence emotion. Whereas the orbitofrontal cortex provides a representation of reward or affective value on a continuous scale, areas beyond the orbitofrontal cortex such as the medial prefrontal cortex area 10 are involved in binary decision-making when a choice must be made. For this decision-making, the orbitofrontal cortex provides a representation of each specific reward in a common currency.

  18. Entorhinal cortex and consolidated memory.

    Science.gov (United States)

    Takehara-Nishiuchi, Kaori

    2014-07-01

    The entorhinal cortex is thought to support rapid encoding of new associations by serving as an interface between the hippocampus and neocortical regions. Although the entorhinal-hippocampal interaction is undoubtedly essential for initial memory acquisition, the entorhinal cortex contributes to memory retrieval even after the hippocampus is no longer necessary. This suggests that during memory consolidation additional synaptic reinforcement may take place within the cortical network, which may change the connectivity of entorhinal cortex with cortical regions other than the hippocampus. Here, I outline behavioral and physiological findings which collectively suggest that memory consolidation involves the gradual strengthening of connection between the entorhinal cortex and the medial prefrontal/anterior cingulate cortex (mPFC/ACC), a region that may permanently store the learned association. This newly formed connection allows for close interaction between the entorhinal cortex and the mPFC/ACC, through which the mPFC/ACC gains access to neocortical regions that store the content of memory. Thus, the entorhinal cortex may serve as a gatekeeper of cortical memory network by selectively interacting either with the hippocampus or mPFC/ACC depending on the age of memory. This model provides a new framework for a modification of cortical memory network during systems consolidation, thereby adding a fresh dimension to future studies on its biological mechanism.

  19. Cerebral cortex modulation of pain

    Institute of Scientific and Technical Information of China (English)

    Yu-feng XIE; Fu-quan HUO; Jing-shi TANG

    2009-01-01

    Pain is a complex experience encompassing sensory-discriminative, affective-motivational and cognitiv e-emotional com-ponents mediated by different mechanisms. Contrary to the traditional view that the cerebral cortex is not involved in pain perception, an extensive cortical network associated with pain processing has been revealed using multiple methods over the past decades. This network consistently includes, at least, the anterior cingulate cortex, the agranular insular cortex, the primary (SⅠ) and secondary somatosensory (SⅡ) cortices, the ventrolateral orbital cortex and the motor cortex. These corti-cal structures constitute the medial and lateral pain systems, the nucleus submedius-ventrolateral orbital cortex-periaque-ductal gray system and motor cortex system, respectively. Multiple neurotransmitters, including opioid, glutamate, GABA and dopamine, are involved in the modulation of pain by these cortical structures. In addition, glial cells may also be in-volved in cortical modulation of pain and serve as one target for pain management research. This review discusses recent studies of pain modulation by these cerebral cortical structures in animals and human.

  20. Registar korisnika i proizvođača prostornih podataka u Federaciji Bosne i Hercegovine : Registry users and producers of spatial data in the Federation of Bosnia and Herzegovina

    Directory of Open Access Journals (Sweden)

    Slobodanka Ključanin

    2016-12-01

    , Strategy IPPFBIH. The strategy describes the way towards the establishment and implementation of IPPFBIH. One of the first projects to be done is the establishment of the Register of Entities and the Register of spatial data resources. This article talks about how they were formed registries in Croatia, and the Register of users and producers of spatial data in the Federation. Their establishment and comparison, did require a lot of time and effort.

  1. Decoding information about dynamically occluded objects in visual cortex.

    Science.gov (United States)

    Erlikhman, Gennady; Caplovitz, Gideon P

    2017-02-01

    During dynamic occlusion, an object passes behind an occluding surface and then later reappears. Even when completely occluded from view, such objects are experienced as continuing to exist or persist behind the occluder even though they are no longer visible. The contents and neural basis of this persistent representation remain poorly understood. Questions remain as to whether there is information maintained about the object itself (i.e. its shape or identity) or non-object-specific information such as its position or velocity as it is tracked behind an occluder, as well as which areas of visual cortex represent such information. Recent studies have found that early visual cortex is activated by "invisible" objects during visual imagery and by unstimulated regions along the path of apparent motion, suggesting that some properties of dynamically occluded objects may also be neurally represented in early visual cortex. We applied functional magnetic resonance imaging in human subjects to examine representations within visual cortex during dynamic occlusion. For gradually occluded, but not for instantly disappearing objects, there was an increase in activity in early visual cortex (V1, V2, and V3). This activity was spatially-specific, corresponding to the occluded location in the visual field. However, the activity did not encode enough information about object identity to discriminate between different kinds of occluded objects (circles vs. stars) using MVPA. In contrast, object identity could be decoded in spatially-specific subregions of higher-order, topographically organized areas such as ventral, lateral, and temporal occipital areas (VO, LO, and TO) as well as the functionally defined LOC and hMT+. These results suggest that early visual cortex may only represent the dynamically occluded object's position or motion path, while later visual areas represent object-specific information.

  2. False memory for context activates the parahippocampal cortex.

    Science.gov (United States)

    Karanian, Jessica M; Slotnick, Scott D

    2014-01-01

    Previous studies have reported greater activity in the parahippocampal cortex during true memory than false memory, which has been interpreted as reflecting greater sensory processing during true memory. However, in these studies, sensory detail and contextual information were confounded. In the present fMRI study, we employed a novel paradigm to dissociate these factors. During encoding, abstract shapes were presented in one of two contexts (i.e., moving or stationary). During retrieval, participants classified shapes as previously "moving" or "stationary." Critically, contextual processing was relatively greater during false memory ("moving" responses to stationary items), while sensory processing was relatively greater during true memory ("moving" responses to moving items). Within the medial temporal lobe, false memory versus true memory produced greater activity in the parahippocampal cortex, whereas true memory versus false memory produced greater activity in the hippocampus. The present results indicate that the parahippocampal cortex mediates contextual processing rather than sensory processing.

  3. Statistical model of natural stimuli predicts edge-like pooling of spatial frequency channels in V2

    Directory of Open Access Journals (Sweden)

    Gutmann Michael

    2005-02-01

    Full Text Available Abstract Background It has been shown that the classical receptive fields of simple and complex cells in the primary visual cortex emerge from the statistical properties of natural images by forcing the cell responses to be maximally sparse or independent. We investigate how to learn features beyond the primary visual cortex from the statistical properties of modelled complex-cell outputs. In previous work, we showed that a new model, non-negative sparse coding, led to the emergence of features which code for contours of a given spatial frequency band. Results We applied ordinary independent component analysis to modelled outputs of complex cells that span different frequency bands. The analysis led to the emergence of features which pool spatially coherent across-frequency activity in the modelled primary visual cortex. Thus, the statistically optimal way of processing complex-cell outputs abandons separate frequency channels, while preserving and even enhancing orientation tuning and spatial localization. As a technical aside, we found that the non-negativity constraint is not necessary: ordinary independent component analysis produces essentially the same results as our previous work. Conclusion We propose that the pooling that emerges allows the features to code for realistic low-level image features related to step edges. Further, the results prove the viability of statistical modelling of natural images as a framework that produces quantitative predictions of visual processing.

  4. Decoding sound and imagery content in early visual cortex.

    Science.gov (United States)

    Vetter, Petra; Smith, Fraser W; Muckli, Lars

    2014-06-02

    Human early visual cortex was traditionally thought to process simple visual features such as orientation, contrast, and spatial frequency via feedforward input from the lateral geniculate nucleus (e.g., [1]). However, the role of nonretinal influence on early visual cortex is so far insufficiently investigated despite much evidence that feedback connections greatly outnumber feedforward connections [2-5]. Here, we explored in five fMRI experiments how information originating from audition and imagery affects the brain activity patterns in early visual cortex in the absence of any feedforward visual stimulation. We show that category-specific information from both complex natural sounds and imagery can be read out from early visual cortex activity in blindfolded participants. The coding of nonretinal information in the activity patterns of early visual cortex is common across actual auditory perception and imagery and may be mediated by higher-level multisensory areas. Furthermore, this coding is robust to mild manipulations of attention and working memory but affected by orthogonal, cognitively demanding visuospatial processing. Crucially, the information fed down to early visual cortex is category specific and generalizes to sound exemplars of the same category, providing evidence for abstract information feedback rather than precise pictorial feedback. Our results suggest that early visual cortex receives nonretinal input from other brain areas when it is generated by auditory perception and/or imagery, and this input carries common abstract information. Our findings are compatible with feedback of predictive information to the earliest visual input level (e.g., [6]), in line with predictive coding models [7-10].

  5. Transient human auditory cortex activation during volitional attention shifting.

    Science.gov (United States)

    Uhlig, Christian Harm; Gutschalk, Alexander

    2017-01-01

    While strong activation of auditory cortex is generally found for exogenous orienting of attention, endogenous, intra-modal shifting of auditory attention has not yet been demonstrated to evoke transient activation of the auditory cortex. Here, we used fMRI to test if endogenous shifting of attention is also associated with transient activation of the auditory cortex. In contrast to previous studies, attention shifts were completely self-initiated and not cued by transient auditory or visual stimuli. Stimuli were two dichotic, continuous streams of tones, whose perceptual grouping was not ambiguous. Participants were instructed to continuously focus on one of the streams and switch between the two after a while, indicating the time and direction of each attentional shift by pressing one of two response buttons. The BOLD response around the time of the button presses revealed robust activation of the auditory cortex, along with activation of a distributed task network. To test if the transient auditory cortex activation was specifically related to auditory orienting, a self-paced motor task was added, where participants were instructed to ignore the auditory stimulation while they pressed the response buttons in alternation and at a similar pace. Results showed that attentional orienting produced stronger activity in auditory cortex, but auditory cortex activation was also observed for button presses without focused attention to the auditory stimulus. The response related to attention shifting was stronger contralateral to the side where attention was shifted to. Contralateral-dominant activation was also observed in dorsal parietal cortex areas, confirming previous observations for auditory attention shifting in studies that used auditory cues.

  6. Development of the cerebellar cortex in the mouse

    Institute of Scientific and Technical Information of China (English)

    Xiangshu Cheng; Jin Du; Dongming Yu; Qiying Jiang; Yanqiu Hu; Lei Wang; Mingshan Li; Jinbo Deng

    2011-01-01

    The cerebellum is a highly conserved structure in the central nervous system of vertebrates, and is involved in the coordination of voluntary motor behavior. Supporting this function, the cerebellar cortex presents a layered structure which requires precise spatial and temporal coordination of proliferation, migration, differentiation, and apoptosis events. The formation of the layered structure in the developing cerebellum remains unclear. The present study investigated the development of the cerebellar cortex. The results demonstrate that the primordium of the cerebellum comprises the ependymal, mantle, and marginal layers at embryonic day 12 (E12). Subsequently, the laminated cerebellar cortex undergoes cell proliferation, differentiation, and migration, and at about postnatal day 0 (P0), the cerebellar cortex presents an external granular layer, a molecular layer, a Purkinje layer, and an internal granular layer. The external granular layer is thickest at P6/7 and disappears at P20. From P0 to P30, the internal granular cells and the Purkinje cells gradually differentiate and develop until maturity. Apoptotic neurons are evident in the layered structure in the developing cerebellar cortex. The external granular layer disappears gradually because of cell migration and apoptosis. The cells of the other layers primarily undergo differentiation, development, and apoptosis.

  7. Distributed Processing and Cortical Specialization for Speech and Environmental Sounds in Human Temporal Cortex

    Science.gov (United States)

    Leech, Robert; Saygin, Ayse Pinar

    2011-01-01

    Using functional MRI, we investigated whether auditory processing of both speech and meaningful non-linguistic environmental sounds in superior and middle temporal cortex relies on a complex and spatially distributed neural system. We found that evidence for spatially distributed processing of speech and environmental sounds in a substantial…

  8. Retrosplenial Cortex Is Required for the Retrieval of Remote Memory for Auditory Cues

    Science.gov (United States)

    Todd, Travis P.; Mehlman, Max L.; Keene, Christopher S.; DeAngeli, Nicole E.; Bucci, David J.

    2016-01-01

    The retrosplenial cortex (RSC) has a well-established role in contextual and spatial learning and memory, consistent with its known connectivity with visuo-spatial association areas. In contrast, RSC appears to have little involvement with delay fear conditioning to an auditory cue. However, all previous studies have examined the contribution of…

  9. Multivoxel fMRI analysis of color tuning in human primary visual cortex

    NARCIS (Netherlands)

    Parkes, Laura M.; Marsman, Jan-Bernard C.; Oxley, David C.; Goulermas, John Y.; Wuerger, Sophie M.

    2009-01-01

    We use multivoxel pattern analysis (MVPA) to study the spatial clustering of color-selective neurons in the human brain. Our main objective was to investigate whether MVPA reveals the spatial arrangements of color-selective neurons in human primary visual cortex (V1). We measured the distributed fMR

  10. Spatial planning

    OpenAIRE

    Dimitrov, Nikola; Koteski, Cane

    2016-01-01

    The professional book ,, Space planning "processed chapters on: space, concept and definition of space, space as a system, spatial economics, economic essence of space, space planning, social determinants of spatial planning, spatial planning as a process, factors development and elements in spatial planning, methodology, components and content of spatial planning stages and types of preparation of spatial planning, spatial planning and industrialization, industrialization, urbanization and s...

  11. Spatial planning

    OpenAIRE

    Dimitrov, Nikola; Koteski, Cane

    2016-01-01

    The professional book ,, Space planning "processed chapters on: space, concept and definition of space, space as a system, spatial economics, economic essence of space, space planning, social determinants of spatial planning, spatial planning as a process, factors development and elements in spatial planning, methodology, components and content of spatial planning stages and types of preparation of spatial planning, spatial planning and industrialization, industrialization, urbanization and s...

  12. MEG reveals a fast pathway from somatosensory cortex to occipital areas via posterior parietal cortex in a blind subject.

    Science.gov (United States)

    Ioannides, Andreas A; Liu, Lichan; Poghosyan, Vahe; Saridis, George A; Gjedde, Albert; Ptito, Maurice; Kupers, Ron

    2013-01-01

    Cross-modal activity in visual cortex of blind subjects has been reported during performance of variety of non-visual tasks. A key unanswered question is through which pathways non-visual inputs are funneled to the visual cortex. Here we used tomographic analysis of single trial magnetoencephalography (MEG) data recorded from one congenitally blind and two sighted subjects after stimulation of the left and right median nerves at three intensities: below sensory threshold, above sensory threshold and above motor threshold; the last sufficient to produce thumb twitching. We identified reproducible brain responses in the primary somatosensory (S1) and motor (M1) cortices at around 20 ms post-stimulus, which were very similar in sighted and blind subjects. Time-frequency analysis revealed strong 45-70 Hz activity at latencies of 20-50 ms in S1 and M1, and posterior parietal cortex Brodmann areas (BA) 7 and 40, which compared to lower frequencies, were substantially more pronounced in the blind than the sighted subjects. Critically, at frequencies from α-band up to 100 Hz we found clear, strong, and widespread responses in the visual cortex of the blind subject, which increased with the intensity of the somatosensory stimuli. Time-delayed mutual information (MI) revealed that in blind subject the stimulus information is funneled from the early somatosensory to visual cortex through posterior parietal BA 7 and 40, projecting first to visual areas V5 and V3, and eventually V1. The flow of information through this pathway occurred in stages characterized by convergence of activations into specific cortical regions. In sighted subjects, no linked activity was found that led from the somatosensory to the visual cortex through any of the studied brain regions. These results provide the first evidence from MEG that in blind subjects, tactile information is routed from primary somatosensory to occipital cortex via the posterior parietal cortex.

  13. MEG reveals a fast pathway from somatosensory cortex to occipital areas via posterior parietal cortex in a blind subject

    Directory of Open Access Journals (Sweden)

    Andreas A Ioannides

    2013-08-01

    Full Text Available Cross-modal activity in visual cortex of blind subjects has been reported during performance of variety of non-visual tasks. A key unanswered question is through which pathways non-visual inputs are funneled to the visual cortex. Here we used tomographic analysis of single trial magnetoencephalography (MEG data recorded from one congenitally blind and two sighted subjects after stimulation of the left and right median nerves at three intensities: below sensory threshold, above sensory threshold and above motor threshold; the last sufficient to produce thumb twitching. We identified reproducible brain responses in the primary somatosensory (S1 and motor (M1 cortices at around 20 ms post-stimulus, which were very similar in sighted and blind subjects. Time-frequency analysis revealed strong 45 to 70 Hz activity at latencies of 20 to 50 ms in S1 and M1, and posterior parietal cortex Brodmann areas (BA 7 and 40, which compared to lower frequencies, were substantially more pronounced in the blind than the sighted subjects. Critically, at frequencies from α-band up to 100 Hz we found clear, strong and widespread responses in the visual cortex of the blind subject, which increased with the intensity of the somatosensory stimuli. Time-delayed mutual information (MI revealed that in blind subject the stimulus information is funneled from the early somatosensory to visual cortex through posterior parietal BA 7 and 40, projecting first to visual areas V5 and V3, and eventually V1. The flow of information through this pathway occured in stages characterized by convergence of activations into specific cortical regions. In sighted subjects, no linked activity was found that led from the somatosensory to the visual cortex through any of the studied brain regions. These results provide the first evidence from MEG that in blind subjects, tactile information is routed from primary somatosensory to occipital cortex via the posterior parietal cortex.

  14. TMS of the occipital cortex induces tactile sensations in the fingers of blind Braille readers

    DEFF Research Database (Denmark)

    Ptito, M; Fumal, A; de Noordhout, A Martens

    2008-01-01

    Various non-visual inputs produce cross-modal responses in the visual cortex of early blind subjects. In order to determine the qualitative experience associated with these occipital activations, we systematically stimulated the entire occipital cortex using single pulse transcranial magnetic...... cortical pathway between the somatosensory cortex and the visual cortex in early blind subjects. These results also add new evidence that the activity of the occipital lobe in the blind takes its qualitative expression from the character of its new input source, therefore supporting the cortical deference...... stimulation (TMS) in early blind subjects and in blindfolded seeing controls. Whereas blindfolded seeing controls reported only phosphenes following occipital cortex stimulation, some of the blind subjects reported tactile sensations in the fingers that were somatotopically organized onto the visual cortex...

  15. The rat retrosplenial cortex as a link for frontal functions: A lesion analysis.

    Science.gov (United States)

    Powell, Anna L; Nelson, Andrew J D; Hindley, Emma; Davies, Moira; Aggleton, John P; Vann, Seralynne D

    2017-09-29

    Cohorts of rats with excitotoxic retrosplenial cortex lesions were tested on four behavioural tasks sensitive to dysfunctions in prelimbic cortex, anterior cingulate cortex, or both. In this way the study tested whether retrosplenial cortex has nonspatial functions that reflect its anatomical interactions with these frontal cortical areas. In Experiment 1, retrosplenial cortex lesions had no apparent effect on a set-shifting digging task that taxed intradimensional and extradimensional attention, as well as reversal learning. Likewise, retrosplenial cortex lesions did not impair a strategy shift task in an automated chamber, which involved switching from visual-based to response-based discriminations and, again, included a reversal (Experiment 2). Indeed, there was evidence that the retrosplenial lesions aided the initial switch to response-based selection. No lesion deficit was found on an automated cost-benefit task that pitted size of reward against effort to achieve that reward (Experiment 3). Finally, while retrosplenial cortex lesions affected matching-to-place task in a T-maze, the profile of deficits differed from that associated with prelimbic cortex damage (Experiment 4). When the task was switched to a nonmatching design, retrosplenial cortex lesions had no apparent effect on performance. The results from the four experiments show that many frontal tasks do not require the retrosplenial cortex, highlighting the specificity of their functional interactions. The results show how retrosplenial cortex lesions spare those learning tasks in which there is no mismatch between the internal and external representations used to guide behavioural choice. In addition, these experiments further highlight the importance of the retrosplenial cortex in solving tasks with a spatial component. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  16. Functional double dissociation within the entorhinal cortex for visual scene-dependent choice behavior

    Science.gov (United States)

    Yoo, Seung-Woo; Lee, Inah

    2017-01-01

    How visual scene memory is processed differentially by the upstream structures of the hippocampus is largely unknown. We sought to dissociate functionally the lateral and medial subdivisions of the entorhinal cortex (LEC and MEC, respectively) in visual scene-dependent tasks by temporarily inactivating the LEC and MEC in the same rat. When the rat made spatial choices in a T-maze using visual scenes displayed on LCD screens, the inactivation of the MEC but not the LEC produced severe deficits in performance. However, when the task required the animal to push a jar or to dig in the sand in the jar using the same scene stimuli, the LEC but not the MEC became important. Our findings suggest that the entorhinal cortex is critical for scene-dependent mnemonic behavior, and the response modality may interact with a sensory modality to determine the involvement of the LEC and MEC in scene-based memory tasks. DOI: http://dx.doi.org/10.7554/eLife.21543.001 PMID:28169828

  17. Functional Neuroanatomy of Spatial Working Memory in Children.

    Science.gov (United States)

    Nelson, Charles A.; Monk, Christopher S.; Lin, Joseph; Carver, Leslie J.; Thomas, Kathleen M.; Truwit, Charles L.

    2000-01-01

    Used functional magnetic resonance imaging (fMRI) to examine spatial working memory in 8- to 11-year-olds tested under 3 conditions. Found that subtracting activation of the motor condition from the memory condition revealed activity in dorsal aspects of the prefrontal cortex and in the posterior parietal and anterior cingulate cortex. Analysis of…

  18. Preparatory Effects of Distractor Suppression: Evidence from Visual Cortex

    OpenAIRE

    Jaap Munneke; Heslenfeld, Dirk J; W Martin Usrey; Jan Theeuwes; Mangun, George R.

    2011-01-01

    Spatial selective attention is the mechanism that facilitates the selection of relevant information over irrelevant information in the visual field. The current study investigated whether foreknowledge of the presence or absence of distractors surrounding an impending target stimulus results in preparatory changes in visual cortex. We cued the location of the target and the presence or absence of distractors surrounding the target while changes in blood oxygen level dependent (BOLD) signals w...

  19. Functions of the orbitofrontal and pregenual cingulate cortex in taste, olfaction, appetite and emotion.

    Science.gov (United States)

    Rolls, E T

    2008-06-01

    Complementary neurophysiological recordings in macaques and functional neuroimaging in humans show that the primary taste cortex in the rostral insula and adjoining frontal operculum provides separate and combined representations of the taste, temperature, and texture (including viscosity and fat texture) of food in the mouth independently of hunger and thus of reward value and pleasantness. One synapse on, in the orbitofrontal cortex, these sensory inputs are for some neurons combined by learning with olfactory and visual inputs. Different neurons respond to different combinations, providing a rich representation of the sensory properties of food. The representation of taste and other food-related stimuli in the orbitofrontal cortex of macaques is found from its lateral border throughout area 13 to within 7 mm of the midline, and in humans the representation of food-related and other pleasant stimuli is found particularly in the medial orbitofrontal cortex. In the orbitofrontal cortex, feeding to satiety with one food decreases the responses of these neurons to that food, but not to other foods, showing that sensory-specific satiety is computed in the primate (including human) orbitofrontal cortex. Consistently, activation of parts of the human orbitofrontal cortex correlates with subjective ratings of the pleasantness of the taste and smell of food. Cognitive factors, such as a word label presented with an odour, influence the pleasantness of the odour, and the activation produced by the odour in the orbitofrontal cortex. Food intake is thus controlled by building a multimodal representation of the sensory properties of food in the orbitofrontal cortex, and gating this representation by satiety signals to produce a representation of the pleasantness or reward value of food which drives food intake. A neuronal representation of taste is also found in the pregenual cingulate cortex, which receives inputs from the orbitofrontal cortex, and in humans many pleasant

  20. Anterior Cingulate Cortex and Cognitive Control: Neuropsychological and Electrophysiological Findings in Two Patients with Lesions to Dorsomedial Prefrontal Cortex

    Science.gov (United States)

    Lovstad, M.; Funderud, I.; Meling, T.; Kramer, U. M.; Voytek, B.; Due-Tonnessen, P.; Endestad, T.; Lindgren, M.; Knight, R. T.; Solbakk, A. K.

    2012-01-01

    Whereas neuroimaging studies of healthy subjects have demonstrated an association between the anterior cingulate cortex (ACC) and cognitive control functions, including response monitoring and error detection, lesion studies are sparse and have produced mixed results. Due to largely normal behavioral test results in two patients with medial…

  1. Orbitofrontal cortex encodes memories within value-based schemas and represents contexts that guide memory retrieval.

    Science.gov (United States)

    Farovik, Anja; Place, Ryan J; McKenzie, Sam; Porter, Blake; Munro, Catherine E; Eichenbaum, Howard

    2015-05-27

    There are a substantial number of studies showing that the orbitofrontal cortex links events to reward values, whereas the hippocampus links events to the context in which they occur. Here we asked how the orbitofrontal cortex contributes to memory where context determines the reward values associated with events. After rats learned object-reward associations that differed depending on the spatial context in which the objects were presented, neuronal ensembles in orbitofrontal cortex represented distinct value-based schemas, each composed of a systematic organization of the representations of objects in the contexts and positions where they were associated with reward or nonreward. Orbitofrontal ensembles also represent the different spatial contexts that define the mappings of stimuli to actions that lead to reward or nonreward. These findings, combined with observations on complementary memory representation within the hippocampus, suggest mechanisms through which prefrontal cortex and the hippocampus interact in support of context-guided memory.

  2. Microstimulation of frontal cortex can reorder a remembered spatial sequence.

    Directory of Open Access Journals (Sweden)

    Mark H Histed

    2006-05-01

    Full Text Available Complex goal-directed behaviors extend over time and thus depend on the ability to serially order memories and assemble compound, temporally coordinated movements. Theories of sequential processing range from simple associative chaining to hierarchical models in which order is encoded explicitly and separately from sequence components. To examine how short-term memory and planning for sequences might be coded, we used microstimulation to perturb neural activity in the supplementary eye field (SEF while animals held a sequence of two cued locations in memory over a short delay. We found that stimulation affected the order in which animals saccaded to the locations, but not the memory for which locations were cued. These results imply that memory for sequential order can be dissociated from that of its components. Furthermore, stimulation of the SEF appeared to bias sequence endpoints to converge toward a location in contralateral space, suggesting that this area encodes sequences in terms of their endpoints rather than their individual components.

  3. Hidden prenatal malnutrition in the rat: role of β₁-adrenoceptors on synaptic plasticity in the frontal cortex.

    Science.gov (United States)

    Flores, Osvaldo; Pérez, Hernán; Valladares, Luis; Morgan, Carlos; Gatica, Arnaldo; Burgos, Héctor; Olivares, Ricardo; Hernández, Alejandro

    2011-10-01

    Moderate reduction in the protein content of the mother's diet (hidden malnutrition) does not alter body and brain weights of rat pups at birth, but leads to dysfunction of neocortical noradrenaline systems together with impaired long-term potentiation and visuo-spatial memory performance. As β₁-adrenoceptors and downstream protein kinase signaling are critically involved in synaptic long-term potentiation and memory formation, we evaluated the β₁-adrenoceptor density and the expression of cyclic-AMP dependent protein kinase, calcium/calmodulin-dependent protein kinase and protein kinase Fyn, in the frontal cortex of prenatally malnourished adult rats. In addition, we also studied if β₁-adrenoceptor activation with the selective β₁ agonist dobutamine could improve deficits of prefrontal cortex long-term potentiation presenting these animals. Prenatally malnourished rats exhibited half of β₁-adrenoceptor binding, together with a 51% and 65% reduction of cyclic AMP-dependent protein kinase α and calcium/calmodulin-dependent protein kinase α expression, respectively, as compared with eutrophic animals. Administration of the selective β₁ agonist dobutamine prior to tetanization completely rescued the ability of the prefrontal cortex to develop and maintain long-term potentiation in the malnourished rats. Results suggest that under-expression of neocortical β₁-adrenoceptors and protein kinase signaling in hidden malnourished rats functionally affects the synaptic networks subserving prefrontal cortex long-term potentiation. β₁-adrenoceptor activation was sufficient to fully recover neocortical plasticity in the PKA- and calcium/calmodulin-dependent protein kinase II-deficient undernourished rats, possibly by producing extra amounts of cAMP and/or by recruiting alternative signaling cascades. © 2011 The Authors. Journal of Neurochemistry © 2011 International Society for Neurochemistry.

  4. Neurophysiologic correlates of fMRI in human motor cortex.

    Science.gov (United States)

    Hermes, Dora; Miller, Kai J; Vansteensel, Mariska J; Aarnoutse, Erik J; Leijten, Frans S S; Ramsey, Nick F

    2012-07-01

    The neurophysiological underpinnings of functional magnetic resonance imaging (fMRI) are not well understood. To understand the relationship between the fMRI blood oxygen level dependent (BOLD) signal and neurophysiology across large areas of cortex, we compared task related BOLD change during simple finger movement to brain surface electric potentials measured on a similar spatial scale using electrocorticography (ECoG). We found that spectral power increases in high frequencies (65-95 Hz), which have been related to local neuronal activity, colocalized with spatially focal BOLD peaks on primary sensorimotor areas. Independent of high frequencies, decreases in low frequency rhythms (neurophysiological mechanisms, one being spatially focal neuronal processing and the other spatially distributed low frequency rhythms. Copyright © 2011 Wiley-Liss, Inc.

  5. Orbitofrontal cortex and its contribution to decision-making.

    Science.gov (United States)

    Wallis, Jonathan D

    2007-01-01

    Damage to orbitofrontal cortex (OFC) produces an unusual pattern of deficits. Patients have intact cognitive abilities but are impaired in making everyday decisions. Here we review anatomical, neuropsychological, and neurophysiological evidence to determine the neuronal mechanisms that might underlie these impairments. We suggest that OFC plays a key role in processing reward: It integrates multiple sources of information regarding the reward outcome to derive a value signal. In effect, OFC calculates how rewarding a reward is. This value signal can then be held in working memory where it can be used by lateral prefrontal cortex to plan and organize behavior toward obtaining the outcome, and by medial prefrontal cortex to evaluate the overall action in terms of its success and the effort that was required. Thus, acting together, these prefrontal areas can ensure that our behavior is most efficiently directed towards satisfying our needs.

  6. Auditory and visual connectivity gradients in frontoparietal cortex.

    Science.gov (United States)

    Braga, Rodrigo M; Hellyer, Peter J; Wise, Richard J S; Leech, Robert

    2017-01-01

    A frontoparietal network of brain regions is often implicated in both auditory and visual information processing. Although it is possible that the same set of multimodal regions subserves both modalities, there is increasing evidence that there is a differentiation of sensory function within frontoparietal cortex. Magnetic resonance imaging (MRI) in humans was used to investigate whether different frontoparietal regions showed intrinsic biases in connectivity with visual or auditory modalities. Structural connectivity was assessed with diffusion tractography and functional connectivity was tested using functional MRI. A dorsal-ventral gradient of function was observed, where connectivity with visual cortex dominates dorsal frontal and parietal connections, while connectivity with auditory cortex dominates ventral frontal and parietal regions. A gradient was also observed along the posterior-anterior axis, although in opposite directions in prefrontal and parietal cortices. The results suggest that the location of neural activity within frontoparietal cortex may be influenced by these intrinsic biases toward visual and auditory processing. Thus, the location of activity in frontoparietal cortex may be influenced as much by stimulus modality as the cognitive demands of a task. It was concluded that stimulus modality was spatially encoded throughout frontal and parietal cortices, and was speculated that such an arrangement allows for top-down modulation of modality-specific information to occur within higher-order cortex. This could provide a potentially faster and more efficient pathway by which top-down selection between sensory modalities could occur, by constraining modulations to within frontal and parietal regions, rather than long-range connections to sensory cortices. Hum Brain Mapp 38:255-270, 2017. © 2016 Wiley Periodicals, Inc.

  7. Parietal rTMS distorts the mental number line: simulating 'spatial' neglect in healthy subjects.

    Science.gov (United States)

    Göbel, Silke M; Calabria, Marco; Farnè, Alessandro; Rossetti, Yves

    2006-01-01

    Patients with left-sided visuospatial neglect, typically after damage to the right parietal lobe, show a systematic bias towards larger numbers when asked to bisect a numerical interval. This has been taken as further evidence for a spatial representation of numbers, perhaps akin to a mental number line with smaller numbers represented to the left and larger numbers to the right. Previously, contralateral neglect-like symptoms in physical line bisection have been induced in healthy subjects with repetitive transcranial magnetic stimulation (rTMS) over right posterior parietal lobe. Here we used rTMS over parietal and occipital sites in healthy subjects to investigate spatial representations in a number bisection task. Subjects were asked to name the midpoint of numerical intervals without calculating. On control trials subjects' behaviour was similar to performance reported in physical line bisection experiments. Subjects underestimated the midpoint of the numerical interval. Repetitive transcranial magnetic stimulation produced representational neglect-like symptoms in number bisection when applied over right posterior parietal cortex (right PPC). Repetitive TMS over right PPC shifted the perceived midpoint of the numerical interval significantly to the right while occipital TMS had no effect on bisection performance. Our study therefore provides further evidence that subjects use spatial representations, perhaps akin to a mental number line, in basic numerical processing tasks. Furthermore, we showed that the right posterior parietal cortex is crucially involved in spatial representation of numbers.

  8. Comparing Spatial Predictions

    KAUST Repository

    Hering, Amanda S.

    2011-11-01

    Under a general loss function, we develop a hypothesis test to determine whether a significant difference in the spatial predictions produced by two competing models exists on average across the entire spatial domain of interest. The null hypothesis is that of no difference, and a spatial loss differential is created based on the observed data, the two sets of predictions, and the loss function chosen by the researcher. The test assumes only isotropy and short-range spatial dependence of the loss differential but does allow it to be non-Gaussian, non-zero-mean, and spatially correlated. Constant and nonconstant spatial trends in the loss differential are treated in two separate cases. Monte Carlo simulations illustrate the size and power properties of this test, and an example based on daily average wind speeds in Oklahoma is used for illustration. Supplemental results are available online. © 2011 American Statistical Association and the American Society for Qualitys.

  9. SPATIAL STABILITY

    OpenAIRE

    Pascal Mossay

    2004-01-01

    We consider a continuous spatial economy consisting of pure exchange local economies. Agents are allowed to change their location over time as a response to spatial utility differentials. These spatial adjustments toward higher utility neighborhoods lead the spatial economy to converge to a spatially uniform allocation of resources, provided that the matrix of price effects is quasi-negative definite. Furthermore our model provides a real time interpretation of the tâtonnement story. Also, sp...

  10. Frequency specific modulation of human somatosensory cortex

    Directory of Open Access Journals (Sweden)

    Matteo eFeurra

    2011-02-01

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

  11. Stimulus Dependence of Gamma Oscillations in Human Visual Cortex.

    Science.gov (United States)

    Hermes, D; Miller, K J; Wandell, B A; Winawer, J

    2015-09-01

    A striking feature of some field potential recordings in visual cortex is a rhythmic oscillation within the gamma band (30-80 Hz). These oscillations have been proposed to underlie computations in perception, attention, and information transmission. Recent studies of cortical field potentials, including human electrocorticography (ECoG), have emphasized another signal within the gamma band, a nonoscillatory, broadband signal, spanning 80-200 Hz. It remains unclear under what conditions gamma oscillations are elicited in visual cortex, whether they are necessary and ubiquitous in visual encoding, and what relationship they have to nonoscillatory, broadband field potentials. We demonstrate that ECoG responses in human visual cortex (V1/V2/V3) can include robust narrowband gamma oscillations, and that these oscillations are reliably elicited by some spatial contrast patterns (luminance gratings) but not by others (noise patterns and many natural images). The gamma oscillations can be conspicuous and robust, but because they are absent for many stimuli, which observers can see and recognize, the oscillations are not necessary for seeing. In contrast, all visual stimuli induced broadband spectral changes in ECoG responses. Asynchronous neural signals in visual cortex, reflected in the broadband ECoG response, can support transmission of information for perception and recognition in the absence of pronounced gamma oscillations.

  12. Parietal cortex mediates perceptual Gestalt grouping independent of stimulus size.

    Science.gov (United States)

    Grassi, Pablo R; Zaretskaya, Natalia; Bartels, Andreas

    2016-06-01

    The integration of local moving elements into a unified gestalt percept has previously been linked to the posterior parietal cortex. There are two possible interpretations for the lack of involvement of other occipital regions. The first is that parietal cortex is indeed uniquely functionally specialized to perform grouping. Another possibility is that other visual regions can perform grouping as well, but that the large spatial separation of the local elements used previously exceeded their neurons' receptive field (RF) sizes, preventing their involvement. In this study we distinguished between these two alternatives. We measured whole-brain activity using fMRI in response to a bistable motion illusion that induced mutually exclusive percepts of either an illusory global Gestalt or of local elements. The stimulus was presented in two sizes, a large version known to activate IPS only, and a version sufficiently small to fit into the RFs of mid-level dorsal regions such as V5/MT. We found that none of the separately localized motion regions apart from parietal cortex showed a preference for global Gestalt perception, even for the smaller version of the stimulus. This outcome suggests that grouping-by-motion is mediated by a specialized size-invariant mechanism with parietal cortex as its anatomical substrate. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Monkey brain cortex imaging by photoacoustic tomography

    OpenAIRE

    Yang, Xinmai; Wang, Lihong V.

    2008-01-01

    Photoacoustic tomography (PAT) is applied to image the brain cortex of a monkey through the intact scalp and skull ex vivo. The reconstructed PAT image shows the major blood vessels on the monkey brain cortex. For comparison, the brain cortex is imaged without the scalp, and then imaged again without the scalp and skull. Ultrasound attenuation through the skull is also measured at various incidence angles. This study demonstrates that PAT of the brain cortex is capable of surviving the ultras...

  14. Lateral-Medial Dissociation in Orbitofrontal Cortex-Hypothalamus Connectivity.

    Science.gov (United States)

    Hirose, Satoshi; Osada, Takahiro; Ogawa, Akitoshi; Tanaka, Masaki; Wada, Hiroyuki; Yoshizawa, Yasunori; Imai, Yoshio; Machida, Toru; Akahane, Masaaki; Shirouzu, Ichiro; Konishi, Seiki

    2016-01-01

    The orbitofrontal cortex (OFC) is involved in cognitive functions, and is also closely related to autonomic functions. The OFC is densely connected with the hypothalamus, a heterogeneous structure controlling autonomic functions that can be divided into two major parts: the lateral and the medial. Resting-state functional connectivity has allowed us to parcellate the cerebral cortex into putative functional areas based on the changes in the spatial pattern of connectivity in the cerebral cortex when a seed point is moved from one voxel to another. In the present high spatial-resolution fMRI study, we investigate the connectivity-based organization of the OFC with reference to the hypothalamus. The OFC was parcellated using resting-state functional connectivity in an individual subject approach, and then the functional connectivity was examined between the parcellated areas in the OFC and the lateral/medial hypothalamus. We found a functional double dissociation in the OFC: the lateral OFC (the lateral orbital gyrus) was more likely connected with the lateral hypothalamus, whereas the medial OFC (the medial orbital and rectal gyri) was more likely connected with the medial hypothalamus. These results demonstrate the fundamental heterogeneity of the OFC, and suggest a potential neural basis of the OFC-hypothalamic functional interaction.

  15. Preparatory effects of distractor suppression: evidence from visual cortex.

    Directory of Open Access Journals (Sweden)

    Jaap Munneke

    Full Text Available Spatial selective attention is the mechanism that facilitates the selection of relevant information over irrelevant information in the visual field. The current study investigated whether foreknowledge of the presence or absence of distractors surrounding an impending target stimulus results in preparatory changes in visual cortex. We cued the location of the target and the presence or absence of distractors surrounding the target while changes in blood oxygen level dependent (BOLD signals were measured. In line with prior work, we found that top-down spatial attention resulted in an increased contralateral BOLD response, evoked by the cue throughout early visual cortex (areas V1, V2 and V3. In addition, cues indicating distractor presence evoked a substantial increase in the magnitude of the BOLD signal in visual area V3, but not in V2 or V1. This study shows that prior knowledge concerning the presence of a distractor results in enhanced attentional modulation of visual cortex, in visual areas where neuronal receptive fields are large enough to encompass both targets and distractors. We interpret these findings as evidence that top-down attentional control processes include active preparatory suppression mechanisms for irrelevant, distracting information in the visual scene.

  16. Preparatory effects of distractor suppression: evidence from visual cortex.

    Science.gov (United States)

    Munneke, Jaap; Heslenfeld, Dirk J; Usrey, W Martin; Theeuwes, Jan; Mangun, George R

    2011-01-01

    Spatial selective attention is the mechanism that facilitates the selection of relevant information over irrelevant information in the visual field. The current study investigated whether foreknowledge of the presence or absence of distractors surrounding an impending target stimulus results in preparatory changes in visual cortex. We cued the location of the target and the presence or absence of distractors surrounding the target while changes in blood oxygen level dependent (BOLD) signals were measured. In line with prior work, we found that top-down spatial attention resulted in an increased contralateral BOLD response, evoked by the cue throughout early visual cortex (areas V1, V2 and V3). In addition, cues indicating distractor presence evoked a substantial increase in the magnitude of the BOLD signal in visual area V3, but not in V2 or V1. This study shows that prior knowledge concerning the presence of a distractor results in enhanced attentional modulation of visual cortex, in visual areas where neuronal receptive fields are large enough to encompass both targets and distractors. We interpret these findings as evidence that top-down attentional control processes include active preparatory suppression mechanisms for irrelevant, distracting information in the visual scene.

  17. The Functions of the Orbitofrontal Cortex

    Science.gov (United States)

    Rolls, Edmund T.

    2004-01-01

    The orbitofrontal cortex contains the secondary taste cortex, in which the reward value of taste is represented. It also contains the secondary and tertiary olfactory cortical areas, in which information about the identity and also about the reward value of odours is represented. The orbitofrontal cortex also receives information about the sight…

  18. Evolutionary specializations of human association cortex

    NARCIS (Netherlands)

    Mars, R.B.; Passingham, R.E.; Neubert, F.X.; Verhagen, L.; Sallet, J.

    2017-01-01

    Is the human brain a big ape brain? We argue that the human association cortex is larger than would be expected for an equivalent ape brain, suggesting human association cortex is a unique adaptation. The internal organization of the human association cortex shows modifications of the ape plan in

  19. Dissecting the actin cortex density and membrane-cortex distance in living cells by super-resolution microscopy

    Science.gov (United States)

    Clausen, M. P.; Colin-York, H.; Schneider, F.; Eggeling, C.; Fritzsche, M.

    2017-02-01

    Nanoscale spacing between the plasma membrane and the underlying cortical actin cytoskeleton profoundly modulates cellular morphology, mechanics, and function. Measuring this distance has been a key challenge in cell biology. Current methods for dissecting the nanoscale spacing either limit themselves to complex survey design using fixed samples or rely on diffraction-limited fluorescence imaging whose spatial resolution is insufficient to quantify distances on the nanoscale. Using dual-color super-resolution STED (stimulated-emission-depletion) microscopy, we here overcome this challenge and accurately measure the density distribution of the cortical actin cytoskeleton and the distance between the actin cortex and the membrane in live Jurkat T-cells. We found an asymmetric cortical actin density distribution with a mean width of 230 (+105/-125) nm. The spatial distances measured between the maximum density peaks of the cortex and the membrane were bi-modally distributed with mean values of 50  ±  15 nm and 120  ±  40 nm, respectively. Taken together with the finite width of the cortex, our results suggest that in some regions the cortical actin is closer than 10 nm to the membrane and a maximum of 20 nm in others.

  20. Producing Presences

    OpenAIRE

    Mandagará, Pedro

    2008-01-01

    Resenha de MENDES, Victor K.; ROCHA, João Cezar de Castro (Eds.). Producing Presences: branching out from Gumbrecht’s work. Dartmouth, Massachusetts: University of Massachusetts Dartmouth, 2007. (Adamastor book series, 2)

  1. The spatiotopic 'visual' cortex of the blind

    Science.gov (United States)

    Likova, Lora

    2012-03-01

    Visual cortex activity in the blind has been shown in sensory tasks. Can it be activated in memory tasks? If so, are inherent features of its organization meaningfully employed? Our recent results in short-term blindfolded subjects imply that human primary visual cortex (V1) may operate as a modality-independent 'sketchpad' for working memory (Likova, 2010a). Interestingly, the spread of the V1 activation approximately corresponded to the spatial extent of the images in terms of their angle of projection to the subject. We now raise the questions of whether under long-term visual deprivation V1 is also employed in non-visual memory task, in particular in congenitally blind individuals, who have never had visual stimulation to guide the development of the visual area organization, and whether such spatial organization is still valid for the same paradigm that was used in blindfolded individuals. The outcome has implications for an emerging reconceptualization of the principles of brain architecture and its reorganization under sensory deprivation. Methods: We used a novel fMRI drawing paradigm in congenitally and late-onset blind, compared with sighted and blindfolded subjects in three conditions of 20s duration, separated by 20s rest-intervals, (i) Tactile Exploration: raised-line images explored and memorized; (ii) Tactile Memory Drawing: drawing the explored image from memory; (iii) Scribble: mindless drawing movements with no memory component. Results and Conclusions: V1 was strongly activated for Tactile Memory Drawing and Tactile Exploration in these totally blind subjects. Remarkably, after training, even in the memory task, the mapping of V1 activation largely corresponded to the angular projection of the tactile stimuli relative to the ego-center (i.e., the effective visual angle at the head); beyond this projective boundary, peripheral V1 signals were dramatically reduced or even suppressed. The matching extent of the activation in the congenitally blind

  2. Spatial Databases

    Science.gov (United States)

    2007-09-19

    for a city . Spatial attributes are used to define the spatial location and extent of spatial objects [35]. The spatial attributes of a spatial object...regarding both geometry and thematic differentiation. It can be used to model 2.5D data (e.g., digital terrain model), as well as 3D data ( walkable ...within a city , if the coverage area of a wireless antenna is considered to be the visible area, then the union of coverage areas of all the antennas in

  3. Infrared thermal imaging of rat somatosensory cortex with whisker stimulation.

    Science.gov (United States)

    Suzuki, Takashi; Ooi, Yasuhiro; Seki, Junji

    2012-04-01

    The present study aims to validate the applicability of infrared (IR) thermal imaging for the study of brain function through experiments on the rat barrel cortex. Regional changes in neural activity within the brain produce alterations in local thermal equilibrium via increases in metabolic activity and blood flow. We studied the relationship between temperature change and neural activity in anesthetized rats using IR imaging to visualize stimulus-induced changes in the somatosensory cortex of the brain. Sensory stimulation of the vibrissae (whiskers) was given for 10 s using an oscillating whisker vibrator (5-mm deflection at 10, 5, and 1 Hz). The brain temperature in the observational region continued to increase significantly with whisker stimulation. The mean peak recorded temperature changes were 0.048 ± 0.028, 0.054 ± 0.036, and 0.097 ± 0.015°C at 10, 5, and 1 Hz, respectively. We also observed that the temperature increase occurred in a focal spot, radiating to encompass a larger region within the contralateral barrel cortex region during single-whisker stimulation. Whisker stimulation also produced ipsilateral cortex temperature increases, which were localized in the same region as the pial arterioles. Temperature increase in the barrel cortex was also observed in rats treated with a calcium channel blocker (nimodipine), which acts to suppress the hemodynamic response to neural activity. Thus the location and area of temperature increase were found to change in accordance with the region of neural activation. These results indicate that IR thermal imaging is viable as a functional quantitative neuroimaging technique.

  4. Plasticity of neuronal response properties in adult cat striate cortex.

    Science.gov (United States)

    McLean, J; Palmer, L A

    1998-01-01

    We have utilized an associative conditioning paradigm to induce changes in the receptive field (RF) properties of neurons in the adult cat striate cortex. During conditioning, the presentation of particular visual stimuli were repeatedly paired with the iontophoretic application of either GABA or glutamate to control postsynaptic firing rates. Similar paradigms have been used in kitten visual cortex to alter RF properties (Fregnac et al., 1988, 1992; Greuel et al., 1988; Shulz & Fregnac, 1992). Roughly half of the cells that were subjected to conditioning with stimuli differing in orientation were found to have orientation tuning curves that were significantly altered. In general, the modification in orientation tuning was not accompanied by a shift in preferred orientation, but rather, responsiveness to stimuli at or near the positively reinforced orientation was increased relative to controls, and responsiveness to stimuli at or near the negatively reinforced orientation was decreased relative to controls. A similar proportion of cells that were subjected to conditioning with stimuli differing in spatial phase were found to have spatial-phase tuning curves that were significantly modified. Conditioning stimuli typically differed by 90 deg in spatial phase, but modifications in spatial-phase angle were generally 30-40 deg. An interesting phenomenon we encountered was that during conditioning, cells often developed a modulated response to counterphased grating stimuli presented at the null spatial phase. We present an example of a simple cell for which the shift in preferred spatial phase measured with counterphased grating stimuli was comparable to the shift in spatial phase computed from a one-dimensional Gabor fit of the space-time RF profile. One of ten cells tested had a significant change in direction selectivity following associative conditioning. The specific and predictable modifications of RF properties induced by our associative conditioning procedure

  5. Developmental and functional biology of the primate fetal adrenal cortex.

    Science.gov (United States)

    Mesiano, S; Jaffe, R B

    1997-06-01

    The unique characteristics of the primate (particularly human) fetal adrenal were first realized in the early 1900s when its morphology was examined in detail and compared with that of other species. The unusual architecture of the human fetal adrenal cortex, with its unique and disproportionately enlarged fetal zone, its compact definitive zone, and its dramatic remodeling soon after birth captured the interest of developmental anatomists. Many detailed anatomical studies describing the morphology of the developing human fetal adrenal were reported between 1920 and 1960, and these morphological descriptions have not changed significantly. More recently, it has become clear that fetal adrenal cortical growth involves cellular hypertrophy, hyperplasia, apoptosis, and migration and is best described by the migration theory, i.e. cells proliferate in the periphery, migrate centripetally, differentiate during their migration to form the functional cortical zones, and then likely undergo apoptosis in the center of the cortex. Consistent with this model, cells of intermediate phenotype, arranged in columnar cords typical of migration, have been identified between the definitive and fetal zones. This cortical area has been referred to as the transitional zone and, based on the expression of steroidogenic enzymes, we consider it to be a functionally distinct cortical zone. Elegant experiments during the 1950s and 1960s demonstrated the central role of the primate fetal adrenal cortex in establishing the estrogenic milieu of pregnancy. Those findings were among the first indications of the function and physiological role of the human fetal adrenal cortex and led Diczfalusy and co-workers to propose the concept of the feto-placental unit, in which DHEA-S produced by the fetal adrenal cortex is used by the placenta for estrogen synthesis. Tissue and cell culture techniques, together with improved steroid assays, revealed that the fetal zone is the primary source of DHEA

  6. Expectation Suppression in Early Visual Cortex Depends on Task Set.

    Science.gov (United States)

    St John-Saaltink, Elexa; Utzerath, Christian; Kok, Peter; Lau, Hakwan C; de Lange, Floris P

    2015-01-01

    Stimulus expectation can modulate neural responses in early sensory cortical regions, with expected stimuli often leading to a reduced neural response. However, it is unclear whether this expectation suppression is an automatic phenomenon or is instead dependent on the type of task a subject is engaged in. To investigate this, human subjects were presented with visual grating stimuli in the periphery that were either predictable or non-predictable while they performed three tasks that differently engaged cognitive resources. In two of the tasks, the predictable stimulus was task-irrelevant and spatial attention was engaged at fixation, with a high load on either perceptual or working memory resources. In the third task, the predictable stimulus was task-relevant, and therefore spatially attended. We observed that expectation suppression is dependent on the cognitive resources engaged by a subjects' current task. When the grating was task-irrelevant, expectation suppression for predictable items was visible in retinotopically specific areas of early visual cortex (V1-V3) during the perceptual task, but it was abolished when working memory was loaded. When the grating was task-relevant and spatially attended, there was no significant effect of expectation in early visual cortex. These results suggest that expectation suppression is not an automatic phenomenon, but dependent on attentional state and type of available cognitive resources.

  7. Pivotal role of anterior cingulate cortex in working memory after traumatic brain injury in youth

    Directory of Open Access Journals (Sweden)

    Fabienne eCazalis

    2011-01-01

    Full Text Available In this fMRI study, the functions of the Anterior Cingulate Cortex were studied in a group of adolescents who had sustained a moderate to severe Traumatic Brain Injury. A spatial working memory task with varying working memory loads, representing experimental conditions of increasing difficulty, was administered.In a cross-sectional comparison between the patients and a matched control group, patients performed worse than Controls, showing longer reaction times and lower response accuracy on the spatial working memory task. Brain imaging findings suggest a possible double-dissociation: activity of the Anterior Cingulate Cortex in the Traumatic Brain Injury group, but not in the Control group, was associated with task difficulty; conversely, activity of the left Sensorimotor Cortex in the Control group, but not in the TBI group, was correlated with task difficulty.In addition to the main cross-sectional study, a longitudinal study of a group of adolescent patients with moderate to severe Traumatic Brain Injury was done using fMRI and the same spatial working memory task. The patient group was studied at two time points: one time point during the post-acute phase and one time point 12 months later, during the chronic phase. Results indicated that patients' behavioral performance improved over time, suggesting cognitive recovery. Brain imaging findings suggest that, over this 12 month period, patients recruited less of the Anterior Cingulate Cortex and more of the left Sensorimotor Cortex in response to increasing task difficulty.The role of Anterior Cingulate Cortex in executive functions following a moderate to severe brain injury in adolescence is discussed within the context of conflicting models of the Anterior Cingulate Cortex functions in the existing literature.

  8. Computational Image Analysis Reveals Intrinsic Multigenerational Differences between Anterior and Posterior Cerebral Cortex Neural Progenitor Cells

    Directory of Open Access Journals (Sweden)

    Mark R. Winter

    2015-10-01

    Full Text Available Time-lapse microscopy can capture patterns of development through multiple divisions for an entire clone of proliferating cells. Images are taken every few minutes over many days, generating data too vast to process completely by hand. Computational analysis of this data can benefit from occasional human guidance. Here we combine improved automated algorithms with minimized human validation to produce fully corrected segmentation, tracking, and lineaging results with dramatic reduction in effort. A web-based viewer provides access to data and results. The improved approach allows efficient analysis of large numbers of clones. Using this method, we studied populations of progenitor cells derived from the anterior and posterior embryonic mouse cerebral cortex, each growing in a standardized culture environment. Progenitors from the anterior cortex were smaller, less motile, and produced smaller clones compared to those from the posterior cortex, demonstrating cell-intrinsic differences that may contribute to the areal organization of the cerebral cortex.

  9. A map of visual space in the primate entorhinal cortex.

    Science.gov (United States)

    Killian, Nathaniel J; Jutras, Michael J; Buffalo, Elizabeth A

    2012-11-29

    Place-modulated activity among neurons in the hippocampal formation presents a means to organize contextual information in the service of memory formation and recall. One particular spatial representation, that of grid cells, has been observed in the entorhinal cortex (EC) of rats and bats, but has yet to be described in single units in primates. Here we examined spatial representations in the EC of head-fixed monkeys performing a free-viewing visual memory task. Individual neurons were identified in the primate EC that emitted action potentials when the monkey fixated multiple discrete locations in the visual field in each of many sequentially presented complex images. These firing fields possessed spatial periodicity similar to a triangular tiling with a corresponding well-defined hexagonal structure in the spatial autocorrelation. Further, these neurons showed theta-band oscillatory activity and changing spatial scale as a function of distance from the rhinal sulcus, which is consistent with previous findings in rodents. These spatial representations may provide a framework to anchor the encoding of stimulus content in a complex visual scene. Together, our results provide a direct demonstration of grid cells in the primate and suggest that EC neurons encode space during visual exploration, even without locomotion.

  10. Disruption of Transient Serotonin Accumulation by Non-Serotonin-Producing Neurons Impairs Cortical Map Development

    Directory of Open Access Journals (Sweden)

    Xiaoning Chen

    2015-01-01

    Full Text Available Polymorphisms that alter serotonin transporter SERT expression and functionality increase the risks for autism and psychiatric traits. Here, we investigate how SERT controls serotonin signaling in developing CNS in mice. SERT is transiently expressed in specific sets of glutamatergic neurons and uptakes extrasynaptic serotonin during perinatal CNS development. We show that SERT expression in glutamatergic thalamocortical axons (TCAs dictates sensory map architecture. Knockout of SERT in TCAs causes lasting alterations in TCA patterning, spatial organizations of cortical neurons, and dendritic arborization in sensory cortex. Pharmacological reduction of serotonin synthesis during the first postnatal week rescues sensory maps in SERTGluΔ mice. Furthermore, knockdown of SERT expression in serotonin-producing neurons does not impair barrel maps. We propose that spatiotemporal SERT expression in non-serotonin-producing neurons represents a determinant in early life genetic programming of cortical circuits. Perturbing this SERT function could be involved in the origin of sensory and cognitive deficits associated with neurodevelopmental disorders.

  11. Modular organization of directionally tuned cells in the motor cortex: Is there a short-range order?

    Science.gov (United States)

    Amirikian, Bagrat; Georgopoulos, Apostolos P.

    2003-10-01

    We investigated the presence of short-range order (<600 μm) in the directional properties of neurons in the motor cortex of the monkey. For that purpose, we developed a quantitative method for the detection of functional cortical modules and used it to examine such potential modules formed by directionally tuned cells. In the functional domain, we labeled each cell by its preferred direction (PD) vector in 3D movement space; in the spatial domain, we used the position of the tip of the recording microelectrode as the cell's coordinate. The images produced by this method represented two orthogonal dimensions in the cortex; one was parallel ("horizontal") and the other perpendicular ("vertical") to the cortical layers. The distribution of directionally tuned cells in these dimensions was nonuniform and highly structured. Specifically, cells with similar PDs tended to segregate into vertically oriented minicolumns 50-100 μm wide and at least 500 μm high. Such minicolumns aggregated across the horizontal dimension in a secondary structure of higher order. In this structure, minicolumns with similar PDs were 200 μm apart and were interleaved with minicolumns representing nearly orthogonal PDs; in addition, nonoverlapping columns representing nearly opposite PDs were 350 μm apart.

  12. Spatial cognition

    Science.gov (United States)

    Kaiser, Mary Kister; Remington, Roger

    1988-01-01

    Spatial cognition is the ability to reason about geometric relationships in the real (or a metaphorical) world based on one or more internal representations of those relationships. The study of spatial cognition is concerned with the representation of spatial knowledge, and our ability to manipulate these representations to solve spatial problems. Spatial cognition is utilized most critically when direct perceptual cues are absent or impoverished. Examples are provided of how human spatial cognitive abilities impact on three areas of space station operator performance: orientation, path planning, and data base management. A videotape provides demonstrations of relevant phenomena (e.g., the importance of orientation for recognition of complex, configural forms). The presentation is represented by abstract and overhead visuals only.

  13. Optogenetic dissection of medial prefrontal cortex circuitry

    Directory of Open Access Journals (Sweden)

    Danai eRiga

    2014-12-01

    Full Text Available The medial prefrontal cortex (mPFC is critically involved in numerous cognitive functions, including attention, inhibitory control, habit formation, working memory and long-term memory. Moreover, through its dense interconnectivity with subcortical regions (e.g. thalamus, striatum, amygdala and hippocampus, the mPFC is thought to exert top-down executive control over the processing of aversive and appetitive stimuli. Because the mPFC has been implicated in the processing of a wide range of cognitive and emotional stimuli, it is thought to function as a central hub in the brain circuitry mediating symptoms of psychiatric disorders. New optogenetics technology enables anatomical and functional dissection of mPFC circuitry with unprecedented spatial and temporal resolution. This provides important novel insights in the contribution of specific neuronal subpopulations and their connectivity to mPFC function in health and disease states. In this review, we present the current knowledge obtained with optogenetic methods concerning mPFC function and dysfunction and integrate this with findings from traditional intervention approaches used to investigate the mPFC circuitry in animal models of cognitive processing and psychiatric disorders.

  14. Optogenetic dissection of medial prefrontal cortex circuitry.

    Science.gov (United States)

    Riga, Danai; Matos, Mariana R; Glas, Annet; Smit, August B; Spijker, Sabine; Van den Oever, Michel C

    2014-01-01

    The medial prefrontal cortex (mPFC) is critically involved in numerous cognitive functions, including attention, inhibitory control, habit formation, working memory and long-term memory. Moreover, through its dense interconnectivity with subcortical regions (e.g., thalamus, striatum, amygdala and hippocampus), the mPFC is thought to exert top-down executive control over the processing of aversive and appetitive stimuli. Because the mPFC has been implicated in the processing of a wide range of cognitive and emotional stimuli, it is thought to function as a central hub in the brain circuitry mediating symptoms of psychiatric disorders. New optogenetics technology enables anatomical and functional dissection of mPFC circuitry with unprecedented spatial and temporal resolution. This provides important novel insights in the contribution of specific neuronal subpopulations and their connectivity to mPFC function in health and disease states. In this review, we present the current knowledge obtained with optogenetic methods concerning mPFC function and dysfunction and integrate this with findings from traditional intervention approaches used to investigate the mPFC circuitry in animal models of cognitive processing and psychiatric disorders.

  15. Representation of lateralization and tonotopy in primary versus secondary human auditory cortex

    NARCIS (Netherlands)

    Langers, Dave R. M.; Backes, Walter H.; van Dijk, Pim

    2007-01-01

    Functional MRI was performed to investigate differences in the basic functional organization of the primary and secondary auditory cortex regarding preferred stimulus lateratization and frequency. A modified sparse acquisition scheme was used to spatially map the characteristics of the auditory cort

  16. LFP spectral peaks in V1 cortex: network resonance and cortico-cortical feedback.

    Science.gov (United States)

    Kang, Kukjin; Shelley, Michael; Henrie, James Andrew; Shapley, Robert

    2010-12-01

    This paper is about how cortical recurrent interactions in primary visual cortex (V1) together with feedback from extrastriate cortex can account for spectral peaks in the V1 local field potential (LFP). Recent studies showed that visual stimulation enhances the γ-band (25-90 Hz) of the LFP power spectrum in macaque V1. The height and location of the γ-band peak in the LFP spectrum were correlated with visual stimulus size. Extensive spatial summation, possibly mediated by feedback connections from extrastriate cortex and long-range horizontal connections in V1, must play a crucial role in the size dependence of the LFP. To analyze stimulus-effects on the LFP of V1 cortex, we propose a network model for the visual cortex that includes two populations of V1 neurons, excitatory and inhibitory, and also includes feedback to V1 from extrastriate cortex. The neural network model for V1 was a resonant system. The model's resonance frequency (ResF) was in the γ-band and varied up or down in frequency depending on cortical feedback. The model's ResF shifted downward with stimulus size, as in the real cortex, because increased size recruited more activity in extrastriate cortex and V1 thereby causing stronger feedback. The model needed to have strong local recurrent inhibition within V1 to obtain ResFs that agree with cortical data. Network resonance as a consequence of recurrent excitation and inhibition appears to be a likely explanation for γ-band peaks in the LFP power spectrum of the primary visual cortex.

  17. [Short-term memory processes during delayed visual differentiation after bilateral removal of the 7th field of the parietal cortex in Rhesus macaca].

    Science.gov (United States)

    Dudkin, K N; Chueva, I V; Makarov, F N; Orlov, I V

    1998-01-01

    Extirpation of the parietal cortex area 7 aggravated delayed visual discrimination of all visual attributes including shape, colour and spatial relationship in adult rhesus monkeys. Oxymetacil improved the shape and colour discrimination alone.

  18. Triterpenoid saponins from Cortex Albiziae

    OpenAIRE

    Zou, Kun; Zhao, Yuying

    2004-01-01

    Cortex Albiziae, the dried stem bark of a leguminous plant, Albizia julibrissin Durazz, was specified in Chinese Pharmacopoeia (1995 edit.) as a traditional Chinese medicine to be used.to relieve melancholia and uneasiness of body and mind, to invigorate the circulation of blood and subside a swelling. In a course of our quality assessment of traditional Chinese medicines, the n-BuOH soluble part of 95% EtOH extracts from the stem barks of Albizia julibrissin was subjected to a series of sol...

  19. The relationship between brain cortical activity and brain oxygenation in the prefrontal cortex during hypergravity exposure.

    Science.gov (United States)

    Smith, Craig; Goswami, Nandu; Robinson, Ryan; von der Wiesche, Melanie; Schneider, Stefan

    2013-04-01

    Artificial gravity has been proposed as a method to counteract the physiological deconditioning of long-duration spaceflight; however, the effects of hypergravity on the central nervous system has had little study. The study aims to investigate whether there is a relationship between prefrontal cortex brain activity and prefrontal cortex oxygenation during exposure to hypergravity. Twelve healthy participants were selected to undergo hypergravity exposure aboard a short-arm human centrifuge. Participants were exposed to hypergravity in the +Gz axis, starting from 0.6 +Gz for women, and 0.8 +Gz for men, and gradually increasing by 0.1 +Gz until the participant showed signs of syncope. Brain cortical activity was measured using electroencephalography (EEG) and localized to the prefrontal cortex using standard low-resolution brain electromagnetic tomography (LORETA). Prefrontal cortex oxygenation was measured using near-infrared spectroscopy (NIRS). A significant increase in prefrontal cortex activity (P Prefrontal cortex oxygenation was significantly decreased during hypergravity exposure, with a decrease in oxyhemoglobin levels (P prefrontal cortex activity and oxy-/deoxyhemoglobin. It is concluded that the increase in prefrontal cortex activity observed during hypergravity was most likely not the result of increased +Gz values resulting in a decreased oxygenation produced through hypergravity exposure. No significant relationship between prefrontal cortex activity and oxygenation measured by NIRS concludes that brain activity during exposure to hypergravity may be difficult to measure using NIRS. Instead, the increase in prefrontal cortex activity might be attributable to psychological stress, which could pose a problem for the use of a short-arm human centrifuge as a countermeasure.

  20. Feeling better: Separate pathways for targeted enhancement of spatial and temporal touch

    Science.gov (United States)

    Yau, Jeffrey M.; Celnik, Pablo; Hsiao, Steven S.; Desmond, John E.

    2013-01-01

    We perceive spatial form and temporal frequency by touch. Although distinct somatosensory neurons represent spatial and temporal information, these neural populations are intermixed throughout the somatosensory system. Here, we show that spatial and temporal touch can be dissociated and separately enhanced via cortical pathways that are normally associated with vision and audition. In Experiments 1 and 2, we found that anodal transcranial direct current stimulation (tDCS) applied over visual cortex, but not auditory cortex, enhances tactile perception of spatial orientation. In Experiments 3 and 4, we found that anodal tDCS over auditory cortex, but not visual cortex, enhances tactile perception of temporal frequency. This double-dissociation reveals separate cortical pathways that selectively support spatial and temporal channels. These results bolster the emerging view that sensory areas process multiple modalities and suggest that supramodal domains may be more fundamental to cortical organizational. PMID:24390826

  1. Effect of swimming training on spatial learning-memory function of rats and its relationship with cAMP and cGMP in hippocampus and prefrontal cortex%游泳训练对大鼠空间学习记忆能力与海马、前额叶皮质环磷酸腺苷、环磷酸鸟苷水平的影响

    Institute of Scientific and Technical Information of China (English)

    谢敏; 徐波; 王泽军

    2009-01-01

    目的:探讨8周游泳训练对大鼠空间学习记忆能力的影响与环磷酸腺苷(cAMP)、环磷酸鸟苷(cGMP)信号传导途径的关系.方法:以大鼠为实验对象,采用Morris水迷官法,研究8周游泳训练对大鼠空间学习记忆能力的作用;采用放射免疫法测定研究8周游泳训练对大鼠海马、前额叶皮质中cGMP、cAMP含量的影响.结果:①Morris水迷宫的测试表明,8周游泳训练后,大鼠的空间记忆能力有一定提高.②与安静组相比,8周游泳训练使大鼠海马cAMP水平非常显著性增加(P<0.01),cAMP/cGMP比值显著性增高(P<0.05),同时,前额叶皮质cAMP与cAMP/cGMP比值显著性增高(P<0.05).结论:8周的游泳训练在提高大鼠空间学习记忆能力的同时伴有海马、前额叶皮质cAMP含量与cAMP/cGMP比值的变化,从而部分揭示了运动促进学习记忆能力提高的可能机制.%Objective: To analyze the influence of long-term swimming training on spatial learning-memory in rats and its relationship with cyclic adenosine monophosphate(cAMP) and cyclic guanosine monophosphate(cGMP) signal transduction pathway. Method: After 3 times adaptable swimming exercises (30min each time), 40 male SD rats were divided into 2 groups: control group (CR, n=20) and exercises, group (TR, n=20). CR group didn't swim, and TR group swam without burden (6 times/week, 60 min each time). After 8 weeks training, 10 rats were selected from both groups respectively for examing of Morris water maze test. Radioimmunoassay was used to measure the levels of cAMP and cGMP in hippocampus and prefrontal cortex of rats. Result: ①Compared with CR group, in TR group learning-memory improved in a certain extent: ②Compared with CR group, in TR group, the level of cAMP in hippocampus enhanced very obviously (P<0.01), the cAMP/cGMP ratio enhanced obviously (P<0.05); in prefrontal cortex the levels of cAMP and cAMP/cGMP ratio enhanced obviously (P<0.05). Conclusion: Swimming

  2. Reorganization of human motor cortex after hand replantation.

    Science.gov (United States)

    Röricht, S; Machetanz, J; Irlbacher, K; Niehaus, L; Biemer, E; Meyer, B U

    2001-08-01

    In 10 patients, reorganizational changes of the motor cortex contralateral to a replanted hand (MCreplant) were studied one to 14 years after complete traumatic amputation and consecutive successful replantation of the hand. The organizational state of MCreplant was assessed for the deafferentated and peripherally deefferentated hand-associated motor cortex and the adjacent motor representation of the proximal arm. For this, response maps were established for the first dorsal interosseus and biceps brachii muscle using focal transcranial magnetic stimulation (TMS) on a skull surface grid. Characteristics of the maps were center of gravity (COG), number of effective stimulation sites, amplitude sum, and amplitudes and response threshold at the optimal stimulation point. The COG is defined by the spatial distribution of response amplitudes on the map and lies over the cortex region with the most excitable corticospinal neurones supplying the recorded muscle. The COG of the biceps map in MCreplant was shifted laterally by 9.8 +/- 3.6 mm (range 5.0-15.7 mm). The extension of the biceps map in MCreplant was increased and the responses were enlarged and had lowered thresholds. For the muscles of the replanted hand, the pattern of reorganization was different: Response amplitudes were enlarged but thresholds, COG, and area of the cortical response map were normal. The different reorganizational phenomena observed for the motor cortical areas supplying the replanted hand and the biceps brachii of the same arm may be influenced by a different extent of deafferentation and by their different role in hand motor control.

  3. Tetanus neurotoxin-induced epilepsy in mouse visual cortex.

    Science.gov (United States)

    Mainardi, Marco; Pietrasanta, Marta; Vannini, Eleonora; Rossetto, Ornella; Caleo, Matteo

    2012-07-01

    Tetanus neurotoxin (TeNT) is a metalloprotease that cleaves the synaptic protein VAMP/synaptobrevin, leading to focal epilepsy. Although this model is widely used in rats, the time course and spatial specificity of TeNT proteolytic action have not been precisely defined. Here we have studied the biochemical, electrographic, and anatomic characteristics of TeNT-induced epilepsy in mouse visual cortex (V1). We found that VAMP cleavage peaked at 10 days, was reduced at 21 days, and completely extinguished 45 days following TeNT delivery. VAMP proteolysis was restricted to the injected V1 and ipsilateral thalamus, whereas it was undetectable in other cortical areas. Electrographic epileptiform activity was evident both during and after the time window of TeNT effects, indicating development of chronic epilepsy. Anatomic analyses found no evidence for long-term tissue damage, such as neuronal loss or microglia activation. These data show that TeNT reliably induces nonlesional epilepsy in mouse cortex. Due to the excellent physiologic knowledge of the visual cortex and the availability of mouse transgenic strains, this model will be useful for examining the network and cellular alterations underlying hyperexcitability within an epileptic focus.

  4. The cutaneous rabbit illusion affects human primary sensory cortex somatotopically.

    Directory of Open Access Journals (Sweden)

    Felix Blankenburg

    2006-03-01

    Full Text Available We used functional magnetic resonance imaging (fMRI to study neural correlates of a robust somatosensory illusion that can dissociate tactile perception from physical stimulation. Repeated rapid stimulation at the wrist, then near the elbow, can create the illusion of touches at intervening locations along the arm, as if a rabbit hopped along it. We examined brain activity in humans using fMRI, with improved spatial resolution, during this version of the classic cutaneous rabbit illusion. As compared with control stimulation at the same skin sites (but in a different order that did not induce the illusion, illusory sequences activated contralateral primary somatosensory cortex, at a somatotopic location corresponding to the filled-in illusory perception on the forearm. Moreover, the amplitude of this somatosensory activation was comparable to that for veridical stimulation including the intervening position on the arm. The illusion additionally activated areas of premotor and prefrontal cortex. These results provide direct evidence that illusory somatosensory percepts can affect primary somatosensory cortex in a manner that corresponds somatotopically to the illusory percept.

  5. Monkey brain cortex imaging by photoacoustic tomography.

    Science.gov (United States)

    Yang, Xinmai; Wang, Lihong V

    2008-01-01

    Photoacoustic tomography (PAT) is applied to image the brain cortex of a monkey through the intact scalp and skull ex vivo. The reconstructed PAT image shows the major blood vessels on the monkey brain cortex. For comparison, the brain cortex is imaged without the scalp, and then imaged again without the scalp and skull. Ultrasound attenuation through the skull is also measured at various incidence angles. This study demonstrates that PAT of the brain cortex is capable of surviving the ultrasound signal attenuation and distortion caused by a relatively thick skull.

  6. Spatializing Time

    DEFF Research Database (Denmark)

    Thomsen, Bodil Marie Stavning

    2011-01-01

    The article analyses some of artist Søren Lose's photographic installations in which time, history and narration is reflected in the creation of allegoric, spatial relations.......The article analyses some of artist Søren Lose's photographic installations in which time, history and narration is reflected in the creation of allegoric, spatial relations....

  7. Spatializing Time

    DEFF Research Database (Denmark)

    2011-01-01

    The article analyses some of artist Søren Lose's photographic installations in which time, history and narration is reflected in the creation of allegoric, spatial relations.......The article analyses some of artist Søren Lose's photographic installations in which time, history and narration is reflected in the creation of allegoric, spatial relations....

  8. Prefrontal cortex glutamate and extraversion.

    Science.gov (United States)

    Grimm, Simone; Schubert, Florian; Jaedke, Maren; Gallinat, Jürgen; Bajbouj, Malek

    2012-10-01

    Extraversion is considered one of the core traits of personality. Low extraversion has been associated with increased vulnerability to affective and anxiety disorders. Brain imaging studies have linked extraversion, approach behaviour and the production of positive emotional states to the dorsolateral prefrontal cortex (DLPFC) and glutamatergic neurotransmission. However, the relationship between extraversion and glutamate in the DLPFC has not been investigated so far. In order to address this issue, absolute glutamate concentrations in the DLPFC and the visual cortex as a control region were measured by 3-Tesla proton magnetic resonance spectroscopy (1H-MRS) in 29 subjects with high and low extraversion. We found increased glutamate levels in the DLPFC of introverts as compared with extraverts. The increased glutamate concentration was specific for the DLPFC and negatively associated with state anxiety. Although preliminary, results indicate altered top-down control of DLPFC due to reduced glutamate concentration as a function of extraversion. Glutamate measurement with 1H-MRS may facilitate the understanding of biological underpinnings of personality traits and psychiatric diseases associated with dysfunctions in approach behaviour and the production of positive emotional states.

  9. Parietal transcranial direct current stimulation modulates primary motor cortex excitability.

    Science.gov (United States)

    Rivera-Urbina, Guadalupe Nathzidy; Batsikadze, Giorgi; Molero-Chamizo, Andrés; Paulus, Walter; Kuo, Min-Fang; Nitsche, Michael A

    2015-03-01

    The posterior parietal cortex is part of the cortical network involved in motor learning and is structurally and functionally connected with the primary motor cortex (M1). Neuroplastic alterations of neuronal connectivity might be an important basis for learning processes. These have however not been explored for parieto-motor connections in humans by transcranial direct current stimulation (tDCS). Exploring tDCS effects on parieto-motor cortical connectivity might be functionally relevant, because tDCS has been shown to improve motor learning. We aimed to explore plastic alterations of parieto-motor cortical connections by tDCS in healthy humans. We measured neuroplastic changes of corticospinal excitability via motor evoked potentials (MEP) elicited by single-pulse transcranial magnetic stimulation (TMS) before and after tDCS over the left posterior parietal cortex (P3), and 3 cm posterior or lateral to P3, to explore the spatial specificity of the effects. Furthermore, short-interval intracortical inhibition/intracortical facilitation (SICI/ICF) over M1, and parieto-motor cortical connectivity were obtained before and after P3 tDCS. The results show polarity-dependent M1 excitability alterations primarily after P3 tDCS. Single-pulse TMS-elicited MEPs, M1 SICI/ICF at 5 and 7 ms and 10 and 15 ms interstimulus intervals (ISIs), and parieto-motor connectivity at 10 and 15 ms ISIs were all enhanced by anodal stimulation. Single pulse-TMS-elicited MEPs, and parieto-motor connectivity at 10 and 15 ms ISIs were reduced by cathodal tDCS. The respective corticospinal excitability alterations lasted for at least 120 min after stimulation. These results show an effect of remote stimulation of parietal areas on M1 excitability. The spatial specificity of the effects and the impact on parietal cortex-motor cortex connections suggest a relevant connectivity-driven effect.

  10. Scene-Selectivity and Retinotopy in Medial Parietal Cortex

    Science.gov (United States)

    Silson, Edward H.; Steel, Adam D.; Baker, Chris I.

    2016-01-01

    Functional imaging studies in human reliably identify a trio of scene-selective regions, one on each of the lateral [occipital place area (OPA)], ventral [parahippocampal place area (PPA)], and medial [retrosplenial complex (RSC)] cortical surfaces. Recently, we demonstrated differential retinotopic biases for the contralateral lower and upper visual fields within OPA and PPA, respectively. Here, using functional magnetic resonance imaging, we combine detailed mapping of both population receptive fields (pRF) and category-selectivity, with independently acquired resting-state functional connectivity analyses, to examine scene and retinotopic processing within medial parietal cortex. We identified a medial scene-selective region, which was contained largely within the posterior and ventral bank of the parieto-occipital sulcus (POS). While this region is typically referred to as RSC, the spatial extent of our scene-selective region typically did not extend into retrosplenial cortex, and thus we adopt the term medial place area (MPA) to refer to this visually defined scene-selective region. Intriguingly MPA co-localized with a region identified solely on the basis of retinotopic sensitivity using pRF analyses. We found that MPA demonstrates a significant contralateral visual field bias, coupled with large pRF sizes. Unlike OPA and PPA, MPA did not show a consistent bias to a single visual quadrant. MPA also co-localized with a region identified by strong differential functional connectivity with PPA and the human face-selective fusiform face area (FFA), commensurate with its functional selectivity. Functional connectivity with OPA was much weaker than with PPA, and similar to that with face-selective occipital face area (OFA), suggesting a closer link with ventral than lateral cortex. Consistent with prior research, we also observed differential functional connectivity in medial parietal cortex for anterior over posterior PPA, as well as a region on the lateral

  11. Cellular properties of principal neurons in the rat entorhinal cortex. II. The medial entorhinal cortex.

    Science.gov (United States)

    Canto, Cathrin B; Witter, Menno P

    2012-06-01

    Principal neurons in different medial entorhinal cortex (MEC) layers show variations in spatial modulation that stabilize between 15 and 30 days postnatally. These in vivo variations are likely due to differences in intrinsic membrane properties and integrative capacities of neurons. The latter depends on inputs and thus potentially on the morphology of principal neurons. In this comprehensive study, we systematically compared the morphological and physiological characteristics of principal neurons in all MEC layers of newborn rats before and after weaning. We recorded simultaneously from up to four post-hoc morphologically identified MEC principal neurons in vitro. Neurons in L(ayer) I-LIII have dendritic and axonal arbors mainly in superficial layers, and LVI neurons mainly in deep layers. The dendritic and axonal trees of part of LV neurons diverge throughout all layers. Physiological properties of principal neurons differ between layers. In LII, most neurons have a prominent sag potential, resonance and membrane oscillations. Neurons in LIII and LVI fire relatively regular, and lack sag potentials and membrane oscillations. LV neurons show the most prominent spike-frequency adaptation and highest input resistance. The data indicate that adult-like principal neuron types can be differentiated early on during postnatal development. The results of the accompanying paper, in which principal neurons in the lateral entorhinal cortex (LEC) were described (Canto and Witter,2011), revealed that significant differences between LEC and MEC exist mainly in LII neurons. We therefore systematically analyzed changes in LII biophysical properties along the mediolateral axis of MEC and LEC. There is a gradient in properties typical for MEC LII neurons. These properties are most pronounced in medially located neurons and become less apparent in more laterally positioned ones. This gradient continues into LEC, such that in LEC medially positioned neurons share some properties

  12. Nonsensory target-dependent organization of piriform cortex.

    Science.gov (United States)

    Chen, Chien-Fu F; Zou, Dong-Jing; Altomare, Clara G; Xu, Lu; Greer, Charles A; Firestein, Stuart J

    2014-11-25

    The piriform cortex (PCX) is the largest component of the olfactory cortex and is hypothesized to be the locus of odor object formation. The distributed odorant representation found in PCX contrasts sharply with the topographical representation seen in other primary sensory cortices, making it difficult to test this view. Recent work in PCX has focused on functional characteristics of these distributed afferent and association fiber systems. However, information regarding the efferent projections of PCX and how those may be involved in odor representation and object recognition has been largely ignored. To investigate this aspect of PCX, we have used the efferent pathway from mouse PCX to the orbitofrontal cortex (OFC). Using double fluorescent retrograde tracing, we identified the output neurons (OPNs) of the PCX that project to two subdivisions of the OFC, the agranular insula and the lateral orbitofrontal cortex (AI-OPNs and LO-OPNs, respectively). We found that both AI-OPNs and LO-OPNs showed a distinct spatial topography within the PCX and fewer than 10% projected to both the AI and the LO as judged by double-labeling. These data revealed that the efferent component of the PCX may be topographically organized. Further, these data suggest a model for functional organization of the PCX in which the OPNs are grouped into parallel output circuits that provide olfactory information to different higher centers. The distributed afferent input from the olfactory bulb and the local PCX association circuits would then ensure a complete olfactory representation, pattern recognition capability, and neuroplasticity in each efferent circuit.

  13. Forward and backward inference in spatial cognition.

    Directory of Open Access Journals (Sweden)

    Will D Penny

    Full Text Available This paper shows that the various computations underlying spatial cognition can be implemented using statistical inference in a single probabilistic model. Inference is implemented using a common set of 'lower-level' computations involving forward and backward inference over time. For example, to estimate where you are in a known environment, forward inference is used to optimally combine location estimates from path integration with those from sensory input. To decide which way to turn to reach a goal, forward inference is used to compute the likelihood of reaching that goal under each option. To work out which environment you are in, forward inference is used to compute the likelihood of sensory observations under the different hypotheses. For reaching sensory goals that require a chaining together of decisions, forward inference can be used to compute a state trajectory that will lead to that goal, and backward inference to refine the route and estimate control signals that produce the required trajectory. We propose that these computations are reflected in recent findings of pattern replay in the mammalian brain. Specifically, that theta sequences reflect decision making, theta flickering reflects model selection, and remote replay reflects route and motor planning. We also propose a mapping of the above computational processes onto lateral and medial entorhinal cortex and hippocampus.

  14. Estimation of reactogenicity of preparations produced on the basis of photoinactivated live vaccines against brucellosis and tularaemia on the organismic level.2. Using the method of speckle-microscopy with high spatial resolution

    Science.gov (United States)

    Ulianova, O. V.; Uianov, S. S.; Li, Pengcheng; Luo, Qingming

    2011-04-01

    The method of speckle microscopy was adapted to estimate the reactogenicity of the prototypes of vaccine preparations against extremely dangerous infections. The theory is proposed to describe the mechanism of formation of the output signal from the super-high spatial resolution speckle microscope. The experimental studies show that bacterial suspensions, irradiated in different regimes of inactivation, do not exert negative influence on the blood microcirculations in laboratory animals.

  15. Conservation of spatial memory function in the pallial forebrain of reptiles and ray-finned fishes.

    Science.gov (United States)

    Rodríguez, Fernando; López, J Carlos; Vargas, J Pedro; Gómez, Yolanda; Broglio, Cristina; Salas, Cosme

    2002-04-01

    The hippocampus of mammals and birds is critical for spatial memory. Neuroanatomical evidence indicates that the medial cortex (MC) of reptiles and the lateral pallium (LP) of ray-finned fishes could be homologous to the hippocampus of mammals and birds. In this work, we studied the effects of lesions to the MC of turtles and to the LP of goldfish in spatial memory. Lesioned animals were trained in place, and cue maze tasks and crucial probe and transfer tests were performed. In experiment 1, MC-lesioned turtles in the place task failed to locate the goal during trials in which new start positions were used, whereas sham animals navigated directly to the goal independently of start location. In contrast, no deficit was observed in cue learning. In experiment 2, LP lesion produced a dramatic impairment in goldfish trained in the place task, whereas medial and dorsal pallium lesions did not decrease accuracy. In addition, none of these pallial lesions produced deficits in cue learning. These results indicate that lesions to the MC of turtles and to the LP of goldfish, like hippocampal lesions in mammals and birds, selectively impair map-like memory representations of the environmental space. Thus, the forebrain structures of reptiles and teleost fish neuroanatomically equivalent to the mammalian and avian hippocampus also share a central role in spatial cognition. Present results suggest that the presence of a hippocampus-dependent spatial memory system is a primitive feature of the vertebrate forebrain that has been conserved through evolution.

  16. Functional Organization of Human Sensorimotor Cortex for Speech Articulation

    Science.gov (United States)

    Bouchard, Kristofer E.; Mesgarani, Nima; Johnson, Keith; Chang, Edward F.

    2013-01-01

    Speaking is one of the most complex actions we perform, yet nearly all of us learn to do it effortlessly. Production of fluent speech requires the precise, coordinated movement of multiple articulators (e.g., lips, jaw, tongue, larynx) over rapid time scales. Here, we used high-resolution, multi-electrode cortical recordings during the production of consonant-vowel syllables to determine the organization of speech sensorimotor cortex in humans. We found speech articulator representations that were somatotopically arranged on ventral pre- and post-central gyri and partially overlapping at individual electrodes. These representations were temporally coordinated as sequences during syllable production. Spatial patterns of cortical activity revealed an emergent, population-level representation, which was organized by phonetic features. Over tens of milliseconds, the spatial patterns transitioned between distinct representations for different consonants and vowels. These results reveal the dynamic organization of speech sensorimotor cortex during the generation of multi-articulator movements underlying our ability to speak. PMID:23426266

  17. Mapping Prefrontal Cortex Functions in Human Infancy

    Science.gov (United States)

    Grossmann, Tobias

    2013-01-01

    It has long been thought that the prefrontal cortex, as the seat of most higher brain functions, is functionally silent during most of infancy. This review highlights recent work concerned with the precise mapping (localization) of brain activation in human infants, providing evidence that prefrontal cortex exhibits functional activation much…

  18. Medial Entorhinal Cortex Lesions Only Partially Disrupt Hippocampal Place Cells and Hippocampus-Dependent Place Memory

    Directory of Open Access Journals (Sweden)

    Jena B. Hales

    2014-11-01

    Full Text Available The entorhinal cortex provides the primary cortical projections to the hippocampus, a brain structure critical for memory. However, it remains unclear how the precise firing patterns of medial entorhinal cortex (MEC cells influence hippocampal physiology and hippocampus-dependent behavior. We found that complete bilateral lesions of the MEC resulted in a lower proportion of active hippocampal cells. The remaining active cells had place fields, but with decreased spatial precision and decreased long-term spatial stability. In addition, MEC rats were as impaired in the water maze as hippocampus rats, while rats with combined MEC and hippocampal lesions had an even greater deficit. However, MEC rats were not impaired on other hippocampus-dependent tasks, including those in which an object location or context was remembered. Thus, the MEC is not necessary for all types of spatial coding or for all types of hippocampus-dependent memory, but it is necessary for the normal acquisition of place memory.

  19. Addiction and the adrenal cortex

    Science.gov (United States)

    Vinson, Gavin P; Brennan, Caroline H

    2013-01-01

    Substantial evidence shows that the hypophyseal–pituitary–adrenal (HPA) axis and corticosteroids are involved in the process of addiction to a variety of agents, and the adrenal cortex has a key role. In general, plasma concentrations of cortisol (or corticosterone in rats or mice) increase on drug withdrawal in a manner that suggests correlation with the behavioural and symptomatic sequelae both in man and in experimental animals. Corticosteroid levels fall back to normal values in resumption of drug intake. The possible interactions between brain corticotrophin releasing hormone (CRH) and proopiomelanocortin (POMC) products and the systemic HPA, and additionally with the local CRH–POMC system in the adrenal gland itself, are complex. Nevertheless, the evidence increasingly suggests that all may be interlinked and that CRH in the brain and brain POMC products interact with the blood-borne HPA directly or indirectly. Corticosteroids themselves are known to affect mood profoundly and may themselves be addictive. Additionally, there is a heightened susceptibility for addicted subjects to relapse in conditions that are associated with change in HPA activity, such as in stress, or at different times of the day. Recent studies give compelling evidence that a significant part of the array of addictive symptoms is directly attributable to the secretory activity of the adrenal cortex and the actions of corticosteroids. Additionally, sex differences in addiction may also be attributable to adrenocortical function: in humans, males may be protected through higher secretion of DHEA (and DHEAS), and in rats, females may be more susceptible because of higher corticosterone secretion. PMID:23825159

  20. Emerging roles of neural stem cells in cerebral cortex development and evolution.

    Science.gov (United States)

    Borrell, Víctor; Reillo, Isabel

    2012-07-01

    Expansion and folding of the cerebral cortex are landmark features of mammalian brain evolution, which are recapitulated during embryonic development. Neural stem cells and their derived germinal cells are coordinated during cerebral cortex development to produce the appropriate amounts and types of neurons. This process is further complicated in gyrencephalic species, where newborn neurons must disperse in the tangential axis to expand the cerebral cortex in surface area. Here, we review advances that have been made over the last decade in understanding the nature and diversity of telencephalic neural stem cells and their roles in cortical development, and we discuss recent progress on how newly identified types of cortical progenitor cell populations may have evolved to drive the expansion and folding of the mammalian cerebral cortex.

  1. Small scale module of the rat granular retrosplenial cortex: an example of minicolumn-like structure of the cerebral cortex

    Directory of Open Access Journals (Sweden)

    Noritaka eIchinohe

    2012-01-01

    Full Text Available Structures associated with the small scale module called minicolumn can be observed frequently in the cerebral cortex. However, the description of functional characteristics remains obscure. A significant confounding factor is the marked variability both in the definition of a minicolumn and in the diagnostic markers for identifying a minicolumn (see for review, Jones, 2000, DeFelipe et al., 2003; Rockland and Ichinohe, 2004. Within a minicolumn, cell columns are easily visualized by conventional Nissl staining. Dendritic bundles were first discovered with Golgi methods, but are more easily seen with MAP2-immunohistochemisty. Myelinated axon bundles can be seen by Tau-immunohistochemistry or myelin staining. Axon bundles of double bouquet cell can be seen by calbindin-immunohistochemistry. The spatial interrelationship among these morphological elements is more complex than expected and is neither clear nor unanimously agreed upon. In this review, I would like to focus first on the minicolumnar structure found in layers 1 and 2 of the rat granular retrosplenial cortex (GRS. This modular structure was first discovered as a combination of prominent apical dendritic bundles from layer 2 pyramidal neurons and spatially-matched thalamocortical patchy inputs (Wyss et al., 2000. Further examination showed more intricate components of this modular structure, which will be reviewed in this paper. Second, the postnatal development of this structure and potential molecular players for its formation will be reviewed. Thirdly, I will discuss how this modular organization is transformed in mutant rodents with a disorganized layer structure in the cerebral cortex (i.e., reeler mouse and Shaking Rat Kawasaki. Lastly, the potential significance of this type of module will be discussed.

  2. Impaired spatial working memory after anterior thalamic lesions: recovery with cerebrolysin and enrichment.

    Science.gov (United States)

    Loukavenko, Elena A; Wolff, Mathieu; Poirier, Guillaume L; Dalrymple-Alford, John C

    2016-05-01

    Lesions to the anterior thalamic nuclei (ATN) in rats produce robust spatial memory deficits that reflect their influence as part of an extended hippocampal system. Recovery of spatial working memory after ATN lesions was examined using a 30-day administration of the neurotrophin cerebrolysin and/or an enriched housing environment. As expected, ATN lesions in standard-housed rats given saline produced severely impaired reinforced spatial alternation when compared to standard-housed rats with sham lesions. Both cerebrolysin and enrichment substantially improved this working memory deficit, including accuracy on trials that required attention to distal cues for successful performance. The combination of cerebrolysin and enrichment was more effective than either treatment alone when the delay between successive runs in a trial was increased to 40 s. Compared to the intact rats, ATN lesions in standard-housed groups produced substantial reduction in c-Fos expression in the retrosplenial cortex, which remained low after cerebrolysin and enrichment treatments. Evidence that multiple treatment strategies restore some memory functions in the current lesion model reinforces the prospect for treatments in human diencephalic amnesia.

  3. Spatial Variability Analysis of Soil Arsenic in Major Fruit Producing Area of Cangzhou City Hebei Province%河北沧州果品主产区土壤砷空间变异性研究

    Institute of Scientific and Technical Information of China (English)

    刘福顺; 刘会玲; 张毅功

    2011-01-01

    Spatial variability of arsenic in the surface layer soil(0-20 cm) from major fruit production area in Xianxian,Botou and Cangxian is studied by using GIS technique and geostatistical analysis.The results show that the average content of soil arsenic is 12.46 mg kg-1 and the pollution risk of soil arsenic is low.The semivariogram of soil arsenic is well fitted by an exponential model.It is found that spatial heterogeneity of soil arsenic is moderate,because the spatial variability is primarily controlled by structural factors of parent material,relief and soil types.Anisotropic analysis indicates that the special distribution of soil arsenic is affected by geological background,stream and suspending particulate.The spatial variability of soil arsenic in the study area can be reflected clearly by the map of the Kriging interpolation.According to the results of the investigation,irrigation with sewage,atmospheric dust arising from burning of coal and use of pesticide and fertilizer are the main human factors of the arsenic distribution.%采用GIS技术和地统计学相结合的方法对河北沧州果品主产区献县、泊头、沧县3个县表层土壤(0~20 cm)砷的空间分异特征进行了分析。结果表明:3个县表层土壤砷的平均值为12.46 mg kg^-1,砷污染存在的风险较低。土壤砷最优理论模型为指数模型,空间结构上具有中等程度空间相关性,说明其空间变异主要是由母质、地形、土壤类型等结构性因素引起的。各向异性分析表明地质背景、河流和飘尘可能影响着土壤砷的分布。Kriging插图结果直观的反映出研究区内土壤砷的空间变异特征。调查结果显示含砷污水的农田灌溉,含砷煤燃烧产生的大气降尘,含砷农药、化肥的使用等是影响土壤砷分布的人为因素。

  4. Functional correlates of distractor suppression during spatial working memory encoding.

    Science.gov (United States)

    Toepper, M; Gebhardt, H; Beblo, T; Thomas, C; Driessen, M; Bischoff, M; Blecker, C R; Vaitl, D; Sammer, G

    2010-02-17

    Executive working memory operations are related to prefrontal regions in the healthy brain. Moreover, neuroimaging data provide evidence for a functional dissociation of ventrolateral and dorsolateral prefrontal cortex. Most authors either suggest a modality-specific or a function-specific prefrontal cortex organization. In the present study we particularly aimed at the identification of different prefrontal cerebral areas that are involved in executive inhibitory processes during spatial working memory encoding. In an fMRI study (functional magnetic resonance imaging) we examined the neural correlates of spatial working memory processing by varying the amount of executive demands of the task. Twenty healthy volunteers performed the Corsi Block-Tapping test (CBT) during fMRI. The CBT requires the storage and reproduction of spatial target sequences. In a second condition, we presented an adapted version of the Block-Suppression-Test (BST). The BST is based on the original CBT but additionally requires the active suppression of visual distraction within the target sequences. In comparison to the CBT performance, particularly the left dorsolateral prefrontal cortex (BA 9) showed more activity during the BST condition. Our results show that the left dorsolateral prefrontal cortex plays a crucial role for executive controlled inhibition of spatial distraction. Furthermore, our findings are in line with the processing model of a functional dorsolateral-ventrolateral prefrontal cortex organization.

  5. Homuncular organization of human motor cortex as indicated by neuromagnetic recordings.

    Science.gov (United States)

    Cheyne, D; Kristeva, R; Deecke, L

    1991-01-14

    Sources of neural activity identified using non-invasive measurements of cerebral magnetic fields (magnetoencephalography) were found to confirm the somatotopic organization of primary motor cortex for movements of different parts of the body in normal human subjects. Somatotopic maps produced with this technique showed slight differences to the 'classic' homunculus obtained from studies using direct cortical stimulation. These findings indicate that neuromagnetic recordings are capable of localizing cortical activity associated with voluntarily produced movements without the use of external stimulation and provide a new method for studying the functional organization of human motor cortex and its role in voluntary movement.

  6. The insular taste cortex contributes to odor quality coding

    Directory of Open Access Journals (Sweden)

    Maria G Veldhuizen

    2010-07-01

    Full Text Available Despite distinct peripheral and central pathways, stimulation of both the olfactory and the gustatory systems may give rise to the sensation of sweetness. Whether there is a common central mechanism producing sweet quality sensations or two discrete mechanisms associated independently with gustatory and olfactory stimuli is currently unknown. Here we used fMRI to determine whether odor sweetness is represented in the piriform olfactory cortex, which is thought to code odor quality, or in the insular taste cortex, which is thought to code taste quality. Fifteen participants sampled two concentrations of a pure sweet taste (sucrose, two sweet food odors (chocolate and strawberry, and two sweet floral odors (lilac and rose. Replicating prior work we found that olfactory stimulation activated the piriform, orbitofrontal and insular cortices. Of these regions, only the insula also responded to sweet taste. More importantly, the magnitude of the response to the food odors, but not to the non-food odors, in this region of insula was positively correlated with odor sweetness rating. These findings demonstrate that insular taste cortex contributes to odor quality coding by representing the taste-like aspects of food odors. Since the effect was specific to the food odors, and only food odors are experienced with taste, we suggest this common central mechanism develops as a function of experiencing flavors.

  7. Spatial Culture

    DEFF Research Database (Denmark)

    2012-01-01

    – 2006. The essays published here allow us to subdivide the field of spatial culture into five major domains, summarized in the titles of chapters in the book: ”Perception and Strategies: Architecture”, ”Politics and Poetics: Urban Spaces”, ”Movements and Cityscape: Textuality”, ”Crisis and Construction......Spatial Culture – A Humanities Perspective Abstract of introductory essay by Henrik Reeh Secured by alliances between socio-political development and cultural practices, a new field of humanistic studies in spatial culture has developed since the 1990s. To focus on links between urban culture...... and modern society is, however, an intellectual practice which has a much longer history. Already in the 1980s, the debate on the modern and the postmodern cited Paris and Los Angeles as spatio-cultural illustrations of these major philosophical concepts. Earlier, in the history of critical studies, the work...

  8. Dr. Otto Soltmann (1876) on development of the motor cortex and recovery after its removal in infancy.

    Science.gov (United States)

    Finger, S; Beyer, T; Koehler, P J

    2000-09-15

    In 1870, Fritsch and Hitzig demonstrated that dogs have a motor cortex. In a chapter published 6 years later, Otto Soltmann studied the functional development of the motor cortex, which he believed functioned in willed movement. He was the first to show that the dog's motor cortex becomes electrically excitable at about 10 days of age, with the contralateral forepaw area appearing first. He also studied the effects of ablating the cortical motor regions unilaterally and bilaterally, and encountered a remarkable degree of sparing of function in his animals operated on as newborns, but not in older-operated dogs. Soltmann turned to the theory of functional take-over (vicariation) to account for the absence of deficits in his young animals. He was especially intrigued by the fact that electrical stimulation of a healthy motor cortex could produce bilateral matched movements, but only in dogs that sustained opposite motor cortex lesions very early in life.

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

    Directory of Open Access Journals (Sweden)

    David F Nichols

    2010-07-01

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

  10. A Major Human White Matter Pathway Between Dorsal and Ventral Visual Cortex.

    Science.gov (United States)

    Takemura, Hiromasa; Rokem, Ariel; Winawer, Jonathan; Yeatman, Jason D; Wandell, Brian A; Pestilli, Franco

    2016-05-01

    Human visual cortex comprises many visual field maps organized into clusters. A standard organization separates visual maps into 2 distinct clusters within ventral and dorsal cortex. We combined fMRI, diffusion MRI, and fiber tractography to identify a major white matter pathway, the vertical occipital fasciculus (VOF), connecting maps within the dorsal and ventral visual cortex. We use a model-based method to assess the statistical evidence supporting several aspects of the VOF wiring pattern. There is strong evidence supporting the hypothesis that dorsal and ventral visual maps communicate through the VOF. The cortical projection zones of the VOF suggest that human ventral (hV4/VO-1) and dorsal (V3A/B) maps exchange substantial information. The VOF appears to be crucial for transmitting signals between regions that encode object properties including form, identity, and color and regions that map spatial information.

  11. Chapter 9--face sensorimotor cortex neuroplasticity associated with intraoral alterations.

    Science.gov (United States)

    Avivi-Arber, Limor; Lee, Jye-Chang; Sessle, Barry J

    2011-01-01

    Loss of teeth or dental attrition is a common clinical occurrence associated with altered somatosensation and impaired oral motor behavior (e.g., mastication, deglutition, phonation). Oral rehabilitation aims at restoring these sensorimotor functions to improve patients' quality of life. Recent studies have implicated neuroplastic changes within the primary motor cortex (M1) in the control of limb motor behaviors following manipulations of sensory inputs to or motor outputs from the central nervous system as well as in learning and adaptation processes. However, limited data are available of the neuroplastic capabilities of face-M1 in relation to orofacial motor functions. The overall objective of our series of studies was to use intracortical microstimulation (ICMS) and recordings of evoked muscle electromyographic activity to test if neuroplastic changes occur in the ICMS-defined motor representations of the tongue-protrusive (genioglossus, GG) and jaw-opening (anterior digastric, AD) muscles within the rat face-M1 and adjacent face primary somatosensory cortex (face-S1) following several different types of intraoral manipulations. We found that a change in diet consistency was not associated with statistically significant changes in AD and GG motor representations. However, incisor extraction resulted, one week later, in a significantly increased AD representation within the contralateral face-M1 and face-S1, and incisor trimming produced time-dependent changes in the AD motor representation. These novel findings underscore the neuroplastic capabilities of the face sensorimotor cortex and point to its possible role in adaptation to an altered peripheral state or altered sensorimotor behavior. Further insights into the neuroplastic capabilities of the face sensorimotor cortex promise to improve therapeutic strategies aimed at the restoration of oral functions, particularly in patients suffering from orofacial sensorimotor deficits or pain.

  12. Entorhinal cortex stimulation modulates amygdala and piriform cortex responses to olfactory bulb inputs in the rat.

    Science.gov (United States)

    Mouly, A-M; Di Scala, G

    2006-01-01

    The rodent olfactory bulb sends direct projections to the piriform cortex and to two structures intimately implicated in memory processes, the entorhinal cortex and the amygdala. The piriform cortex has monosynaptic projections with the amygdala and the piriform cortex and is therefore in a position to modulate olfactory input either directly in the piriform cortex, or via the amygdala. In order to investigate this hypothesis, field potential signals induced in anesthetized rats by electrical stimulation of the olfactory bulb or the entorhinal cortex were recorded simultaneously in the piriform cortex (anterior part and posterior part) and the amygdala (basolateral nucleus and cortical nucleus). Single-site paired-pulse stimulation was used to assess the time courses of short-term inhibition and facilitation in each recording site in response to electrical stimulation of the olfactory bulb and entorhinal cortex. Paired-pulse stimulation of the olfactory bulb induced homosynaptic inhibition for short interpulse interpulse intervals (20-30 ms) in all the recording sites, with a significantly lower degree of inhibition in the anterior piriform cortex than in the other structures. At longer intervals (40-80 ms), paired-pulse facilitation was observed in all the structures. Paired-pulse stimulation of the entorhinal cortex mainly resulted in inhibition for the shortest interval duration (20 ms) in anterior piriform cortex, posterior piriform cortex and amygdala basolateral but not cortical nucleus. Double-site paired-pulse stimulation was then applied to determine if stimulation of the entorhinal cortex can modulate responses to olfactory bulb stimulation. For short interpulse intervals (20 ms) heterosynaptic inhibition was observed in anterior piriform cortex, posterior piriform cortex and amygdala basolateral but not cortical nucleus. The level of inhibition was greater in the basolateral nucleus than in the other structures. Taken together these data suggest that the

  13. Particle detector spatial resolution

    Science.gov (United States)

    Perez-Mendez, V.

    1992-12-15

    Method and apparatus for producing separated columns of scintillation layer material, for use in detection of X-rays and high energy charged particles with improved spatial resolution is disclosed. A pattern of ridges or projections is formed on one surface of a substrate layer or in a thin polyimide layer, and the scintillation layer is grown at controlled temperature and growth rate on the ridge-containing material. The scintillation material preferentially forms cylinders or columns, separated by gaps conforming to the pattern of ridges, and these columns direct most of the light produced in the scintillation layer along individual columns for subsequent detection in a photodiode layer. The gaps may be filled with a light-absorbing material to further enhance the spatial resolution of the particle detector. 12 figs.

  14. Spatial Interpolation.

    NARCIS (Netherlands)

    Stein, A.

    1991-01-01

    The theory and practical application of techniques of statistical interpolation are studied in this thesis, and new developments in multivariate spatial interpolation and the design of sampling plans are discussed. Several applications to studies in soil science are presented.Sampling s

  15. TMS of the occipital cortex induces tactile sensations in the fingers of blind Braille readers.

    Science.gov (United States)

    Ptito, M; Fumal, A; de Noordhout, A Martens; Schoenen, J; Gjedde, A; Kupers, R

    2008-01-01

    Various non-visual inputs produce cross-modal responses in the visual cortex of early blind subjects. In order to determine the qualitative experience associated with these occipital activations, we systematically stimulated the entire occipital cortex using single pulse transcranial magnetic stimulation (TMS) in early blind subjects and in blindfolded seeing controls. Whereas blindfolded seeing controls reported only phosphenes following occipital cortex stimulation, some of the blind subjects reported tactile sensations in the fingers that were somatotopically organized onto the visual cortex. The number of cortical sites inducing tactile sensations appeared to be related to the number of hours of Braille reading per day, Braille reading speed and dexterity. These data, taken in conjunction with previous anatomical, behavioural and functional imaging results, suggest the presence of a polysynaptic cortical pathway between the somatosensory cortex and the visual cortex in early blind subjects. These results also add new evidence that the activity of the occipital lobe in the blind takes its qualitative expression from the character of its new input source, therefore supporting the cortical deference hypothesis.

  16. Expansion of the piriform cortex contributes to corticothalamic pathfinding defects in Gli3 conditional mutants.

    Science.gov (United States)

    Amaniti, Eleni-Maria; Fu, Chaoying; Lewis, Sean; Saisana, Marina; Magnani, Dario; Mason, John O; Theil, Thomas

    2015-02-01

    The corticothalamic and thalamocortical tracts play essential roles in the communication between the cortex and thalamus. During development, axons forming these tracts have to follow a complex path to reach their target areas. While much attention has been paid to the mechanisms regulating their passage through the ventral telencephalon, very little is known about how the developing cortex contributes to corticothalamic/thalamocortical tract formation. Gli3 encodes a zinc finger transcription factor widely expressed in telencephalic progenitors which has important roles in corticothalamic and thalamocortical pathfinding. Here, we conditionally inactivated Gli3 in dorsal telencephalic progenitors to determine its role in corticothalamic tract formation. In Emx1Cre;Gli3(fl/fl) mutants, only a few corticothalamic axons enter the striatum in a restricted dorsal domain. This restricted entry correlates with a medial expansion of the piriform cortex. Transplantation experiments showed that the expanded piriform cortex repels corticofugal axons. Moreover, expression of Sema5B, a chemorepellent for corticofugal axons produced by the piriform cortex, is similarly expanded. Finally, time course analysis revealed an expansion of the ventral pallial progenitor domain which gives rise to the piriform cortex. Hence, control of lateral cortical development by Gli3 at the progenitor level is crucial for corticothalamic pathfinding.

  17. Spatial Standard Observer

    Science.gov (United States)

    Watson, Andrew B. (Inventor)

    2012-01-01

    The present invention relates to devices and methods for the measurement and/or for the specification of the perceptual intensity of a visual image, or the perceptual distance between a pair of images. Grayscale test and reference images are processed to produce test and reference luminance images. A luminance filter function is convolved with the reference luminance image to produce a local mean luminance reference image. Test and reference contrast images are produced from the local mean luminance reference image and the test and reference luminance images respectively, followed by application of a contrast sensitivity filter. The resulting images are combined according to mathematical prescriptions to produce a Just Noticeable Difference, JND value, indicative of a Spatial Standard Observer, SSO. Some embodiments include masking functions, window functions, special treatment for images lying on or near borders and pre-processing of test images.

  18. Tonotopic organization of human auditory association cortex.

    Science.gov (United States)

    Cansino, S; Williamson, S J; Karron, D

    1994-11-07

    Neuromagnetic studies of responses in human auditory association cortex for tone burst stimuli provide evidence for a tonotopic organization. The magnetic source image for the 100 ms component evoked by the onset of a tone is qualitatively similar to that of primary cortex, with responses lying deeper beneath the scalp for progressively higher tone frequencies. However, the tonotopic sequence of association cortex in three subjects is found largely within the superior temporal sulcus, although in the right hemisphere of one subject some sources may be closer to the inferior temporal sulcus. The locus of responses for individual subjects suggests a progression across the cortical surface that is approximately proportional to the logarithm of the tone frequency, as observed previously for primary cortex, with the span of 10 mm for each decade in frequency being comparable for the two areas.

  19. Where does TMS Stimulate the Motor Cortex?

    DEFF Research Database (Denmark)

    Bungert, Andreas; Antunes, André; Espenhahn, Svenja;

    2016-01-01

    Much of our knowledge on the physiological mechanisms of transcranial magnetic stimulation (TMS) stems from studies which targeted the human motor cortex. However, it is still unclear which part of the motor cortex is predominantly affected by TMS. Considering that the motor cortex consists...... of functionally and histologically distinct subareas, this also renders the hypotheses on the physiological TMS effects uncertain. We use the finite element method (FEM) and magnetic resonance image-based individual head models to get realistic estimates of the electric field induced by TMS. The field changes...... in different subparts of the motor cortex are compared with electrophysiological threshold changes of 2 hand muscles when systematically varying the coil orientation in measurements. We demonstrate that TMS stimulates the region around the gyral crown and that the maximal electric field strength in this region...

  20. Contextual Learning Induces Dendritic Spine Clustering in Retrosplenial Cortex

    Directory of Open Access Journals (Sweden)

    Adam C Frank

    2014-03-01

    Full Text Available Molecular and electrophysiological studies find convergent evidence suggesting that plasticity within a dendritic tree is not randomly dispersed, but rather clustered into functional groups. Further, results from in silico neuronal modeling show that clustered plasticity is able to increase storage capacity 45 times compared to dispersed plasticity. Recent in vivo work utilizing chronic 2-photon microscopy tested the clustering hypothesis and showed that repetitive motor learning is able to induce clustered addition of new dendritic spines on apical dendrites of L5 neurons in primary motor cortex; moreover, clustered spines were found to be more stable than non-clustered spines, suggesting a physiological role for spine clustering. To further test this hypothesis we used in vivo 2-photon imaging in Thy1-YFP-H mice to chronically examine dendritic spine dynamics in retrosplenial cortex (RSC during spatial learning. RSC is a key component of an extended spatial learning and memory circuit that includes hippocampus and entorhinal cortex. Importantly, RSC is known from both lesion and immediate early gene studies to be critically involved in spatial learning and more specifically in contextual fear conditioning. We utilized a modified contextual fear conditioning protocol wherein animals received a mild foot shock each day for five days; this protocol induces gradual increases in context freezing over several days before the animals reach a behavioral plateau. We coupled behavioral training with four separate in vivo imaging sessions, two before training begins, one early in training, and a final session after training is complete. This allowed us to image spine dynamics before training as well as early in learning and after animals had reached behavioral asymptote. We find that this contextual learning protocol induces a statistically significant increase in the formation of clusters of new dendritic spines in trained animals when compared to home

  1. Development of binocular vision in the kitten's striate cortex.

    Science.gov (United States)

    Freeman, R D; Ohzawa, I

    1992-12-01

    Studies of the development and plasticity of the visual pathway are well documented, but a basic question remains open: what is the physiological status of the system prior to extensive visual experience? Somewhat conflicting answers have been put forward, and in a major area, binocular vision, reports have ranged from severe immaturity to well-developed maturity. This is an important question to resolve since binocular cells in the visual cortex are thought to be the neural substrate for stereoscopic depth perception. We have addressed this question by recording from single cells in the striate cortex of kittens at postnatal ages 2, 3, and 4 weeks and from adults for comparison. Gratings with sinusoidal luminance distribution are presented to left, right, or both eyes. For each cell, we determine optimal values for orientation and spatial frequency. Relative phase (retinal disparity) is then varied in a dichoptic sequence so that binocular interaction may be studied. Results are as follows. In the normal adult, we have shown in previous work that most binocular interaction in the visual cortex can be accounted for on the basis of linear summation. Results from 3 and 4 week postnatal kittens are closely similar to those from adults. All types of binocular interaction found in adults are present in kittens. This includes phase-specific and non-phase-specific suppression or facilitation. Furthermore, monocular and binocular tuning characteristics are comparable in kittens and adults. The clear changes that occur with age are optimal spatial frequencies and peak responses. In addition, at 2 weeks, there is a substantially higher proportion of monocular cells compared to other ages and correspondingly, lower relative numbers of cells that exhibit phase-specific or suppressive binocular interactions. From increases in optimal spatial frequency and interpupillary distance with age, we calculated predicted changes in binocular disparity thresholds (stereo acuity) with age

  2. Food related processes in the insular cortex

    Directory of Open Access Journals (Sweden)

    Sabine eFrank

    2013-08-01

    Full Text Available The insular cortex is a multimodal brain region with regional cytoarchitectonic differences indicating various functional specializations. As a multisensory neural node, the insular cortex integrates perception, emotion, interoceptive awareness, cognition, and gustation. Regarding the latter, predominantly the anterior part of the insular cortex is regarded as the primary taste cortex.In this review, we will specifically focus on the involvement of the insula in food processing and on multimodal integration of food-related items. Influencing factors of insular activation elicited by various foods range from calorie-content to the internal physiologic state, body mass index or eating behavior. Sensory perception of food-related stimuli including seeing, smelling, and tasting elicits increased activation in the anterior and mid-dorsal part of the insular cortex. Apart from the pure sensory gustatory processing, there is also a strong association with the rewarding/hedonic aspects of food items, which is reflected in higher insular activity and stronger connections to other reward-related areas. Interestingly, the processing of food items has been found to elicit different insular activation in lean compared to obese subjects and in patients suffering from an eating disorder (anorexia nervosa, bulimia nervosa. The knowledge of functional differences in the insular cortex opens up the opportunity for possible noninvasive treatment approaches for obesity and eating disorders. To target brain functions directly, real-time functional magnetic resonance imaging neurofeedback offers a state-of-the-art tool to learn to control the anterior insular cortex activity voluntarily. First evidence indicates that obese adults have an enhanced ability to regulate the anterior insular cortex.

  3. Motor Cortex Stimulation in Parkinson's Disease

    OpenAIRE

    Marisa De Rose; Giusy Guzzi; Domenico Bosco; Mary Romano; Serena Marianna Lavano; Massimiliano Plastino; Giorgio Volpentesta; Rosa Marotta; Angelo Lavano

    2012-01-01

    Motor Cortex Stimulation (MCS) is less efficacious than Deep Brain Stimulation (DBS) in Parkinson's disease. However, it might be proposed to patients excluded from DBS or unresponsive to DBS. Ten patients with advanced PD underwent unilateral MCS contralaterally to the worst clinical side. A plate electrode was positioned over the motor cortex in the epidural space through single burr hole after identification of the area with neuronavigation and neurophysiological tests. Clinical assessment...

  4. The left occipitotemporal cortex does not show preferential activity for words.

    Science.gov (United States)

    Vogel, Alecia C; Petersen, Steven E; Schlaggar, Bradley L

    2012-12-01

    Regions in left occipitotemporal (OT) cortex, including the putative visual word form area, are among the most commonly activated in imaging studies of single-word reading. It remains unclear whether this part of the brain is more precisely characterized as specialized for words and/or letters or contains more general-use visual regions having properties useful for processing word stimuli, among others. In Analysis 1, we found no evidence of greater activity in left OT regions for words or letter strings relative to other high-spatial frequency high-contrast stimuli, including line drawings and Amharic strings (which constitute the Ethiopian writing system). In Analysis 2, we further investigated processing characteristics of OT cortex potentially useful in reading. Analysis 2 showed that a specific part of OT cortex 1) is responsive to visual feature complexity, measured by the number of strokes forming groups of letters or Amharic strings and 2) processes learned combinations of characters, such as those in words and pseudowords, as groups but does not do so in consonant and Amharic strings. Together, these results indicate that while regions of left OT cortex are not specialized for words, at least part of OT cortex has properties particularly useful for processing words and letters.

  5. Novel experience induces persistent sleep-dependent plasticity in the cortex but not in the hippocampus

    Directory of Open Access Journals (Sweden)

    Sidarta Ribeiro

    2007-10-01

    Full Text Available Episodic and spatial memories engage the hippocampus during acquisition but migrate to the cerebral cortex over time. We have recently proposed that the interplay between slow-wave (SWS and rapid eye movement (REM sleep propagates recent synaptic changes from the hippocampus to the cortex. To test this theory, we jointly assessed extracellular neuronal activity, local field potentials (LFP, and expression levels of plasticity-related immediate-early genes (IEG arc and zif-268 in rats exposed to novel spatio-tactile experience. Post-experience firing rate increases were strongest in SWS and lasted much longer in the cortex (hours than in the hippocampus (minutes. During REM sleep, firing rates showed strong temporal dependence across brain areas: cortical activation during experience predicted hippocampal activity in the first post-experience hour, while hippocampal activation during experience predicted cortical activity in the third post-experience hour. Four hours after experience, IEG expression was specifically upregulated during REM sleep in the cortex, but not in the hippocampus. Arc gene expression in the cortex was proportional to LFP amplitude in the spindle-range (10-14 Hz but not to firing rates, as expected from signals more related to dendritic input than to somatic output. The results indicate that hippocampo-cortical activation during waking is followed by multiple waves of cortical plasticity as full sleep cycles recur. The absence of equivalent changes in the hippocampus may explain its mnemonic disengagement over time.

  6. [Investigation on chemical constituents of processed products of Eucommiae Cortex].

    Science.gov (United States)

    Tao, Yi; Sheng, Chen; Li, Wei-dong; Cai, Bao-chang; Lu, Tu-lin

    2014-11-01

    According to the 2010 Chinese pharmacopeia, salt processed and charcoal processed Eucommiae Cortex were pre- pared. HPLC-DAD analysis of the content of the bark and leaf of Eucommiae Cortex showed that the bark of Eucommiae Cortex mainly contained lignans such as pinoresinol glucose and iridoid including genipin, geniposide, geniposidic acid, while the leaf of Eucommiae Cortex consisted of flavonoids such as quercetin and phenolic compound such as chlorogenic acid. The content of pinoresinol diglucoside in the bark of Eucommiae Cortex was about 18 times more than that in the leaf of Eucommiae Cortex. The content of pinoresinol diglucoside in salted and charcoal processed Eucommiae Cortex decreased approximately by 30% and 85%, respectively. The content of genipin, geniposide and geniposidic acid in the bark of Eucommiae Cortex was about 3 times, 23 times, 28 times more than that in the leaf of Eucommiae Cortex. The content of genipin, geniposide and geniposidic acid in salted Eucommiae Cortex were reduced by 25%, 40% and 40%, respectively. The content of genipin, geniposide and geniposidic acid in charcoal processed Eucommiae Cortex were reduced by 98%, 70%, 70%, respectively. The content of caffeic acid in bark of Eucommiae Cortex was about 3 times more than that in the leaf of Eucommiae Cortex. The content of caffeic acid was decreased by about 50% in the salted Eucommiae Cortex. While the content of caffeic acid in charcoal processed Eucommiae Cortex was decreased approximately 75%; the content of chlorogenic acid in bark of Eucommiae Cortex was about 1/6 of that in the leaf of Eucommiae Cortex. The content of chlorogenic acid in salted and charcoal processed Eucommiae Cortex decreased by 40% and 75%, respectively; the content of quercetin in bark of Eucommiae Cortex was only 1/40 of that in the leaf of Eucommiae Cortex. The content of quercetin in salted and charcoal processed Eucommiae Cortex were reduced by 60% and 50%, respectively.

  7. Cortical fMRI activation produced by attentive tracking of moving targets.

    Science.gov (United States)

    Culham, J C; Brandt, S A; Cavanagh, P; Kanwisher, N G; Dale, A M; Tootell, R B

    1998-11-01

    Attention can be used to keep track of moving items, particularly when there are multiple targets of interest that cannot all be followed with eye movements. Functional magnetic resonance imaging (fMRI) was used to investigate cortical regions involved in attentive tracking. Cortical flattening techniques facilitated within-subject comparisons of activation produced by attentive tracking, visual motion, discrete attention shifts, and eye movements. In the main task, subjects viewed a display of nine green "bouncing balls" and used attention to mentally track a subset of them while fixating. At the start of each attentive-tracking condition, several target balls (e.g., 3/9) turned red for 2 s and then reverted to green. Subjects then used attention to keep track of the previously indicated targets, which were otherwise indistinguishable from the nontargets. Attentive-tracking conditions alternated with passive viewing of the same display when no targets had been indicated. Subjects were pretested with an eye-movement monitor to ensure they could perform the task accurately while fixating. For seven subjects, functional activation was superimposed on each individual's cortically unfolded surface. Comparisons between attentive tracking and passive viewing revealed bilateral activation in parietal cortex (intraparietal sulcus, postcentral sulcus, superior parietal lobule, and precuneus), frontal cortex (frontal eye fields and precentral sulcus), and the MT complex (including motion-selective areas MT and MST). Attentional enhancement was absent in early visual areas and weak in the MT complex. However, in parietal and frontal areas, the signal change produced by the moving stimuli was more than doubled when items were tracked attentively. Comparisons between attentive tracking and attention shifting revealed essentially identical activation patterns that differed only in the magnitude of activation. This suggests that parietal cortex is involved not only in discrete

  8. Disruption of the direct perforant path input to the CA1 subregion of the dorsal hippocampus interferes with spatial working memory and novelty detection.

    Science.gov (United States)

    Vago, David R; Kesner, Raymond P

    2008-06-03

    Subregional analyses of the hippocampus suggest CA1-dependent memory processes rely heavily upon interactions between the CA1 subregion and entorhinal cortex. There is evidence that the direct perforant path (pp) projection to CA1 is selectively modulated by dopamine while having little to no effect on the Schaffer collateral (SC) projection to CA1. The current study takes advantage of this pharmacological dissociation to demonstrate that local infusion of the non-selective dopamine agonist, apomorphine (10, 15 microg), into the CA1 subregion of awake animals produces impairments in working memory at intermediate (5 min), but not short-term (10 s) delays within a delayed non-match-to-place task on a radial arm maze. Sustained impairments were also found in a novel context with similar object-space relationships. Infusion of apomorphine into CA1 is also shown here to produce deficits in spatial, but not non-spatial novelty detection within an object exploration paradigm. In contrast, apomorphine produces no behavioral deficits when infused into the CA3 subregion or overlying cortex. These behavioral studies are supported by previous electrophysiological data that demonstrate local infusion of the same doses of apomorphine significantly modifies evoked responses in the distal dendrites of CA1 following angular bundle stimulation, but produces no significant effects in the proximal dendritic layer following stimulation of the SC. These results support a modulatory role for dopamine in EC-CA1, but not CA3-CA1 circuitry, and suggest the possibility of a fundamental role for EC-CA1 synaptic transmission in terms of detection of spatial novelty, and intermediate-term, but not short-term spatial working memory or object-novelty detection.

  9. The adrenal cortex and life.

    Science.gov (United States)

    Vinson, Gavin P

    2009-03-05

    The template for our understanding of the physiological role of the adrenal cortex was set by Hans Selye, who demonstrated its key involvement in the response to stress, of whatever origin, and who also introduced the terms glucocorticoid and mineralocorticoid. Despite this, from the late 1940s on there was certainly general awareness of the multiple actions of glucocorticoids, including effects on the thymus and immune system, cardiovascular system, water balance, and the CNS. For these reasons, and perhaps because in the early studies of the actions of individual steroids there was less clear-cut difference between them, there was some initial resistance to the use of these terms. Today they are universal and unchallenged. It can be argued that, with respect to the glucocorticoids, this term colours our perception of their physiological importance, and may be misleading. By taking evidence from disease states, emphasis is placed on extreme conditions that do not necessarily reveal normal physiology. In particular, evidence for the role of glucocorticoid regulation of gluconeogenesis and blood glucose in the normal subject or animal is inconclusive. Similarly, while highly plausible theories explaining glucocorticoid actions on inflammation or the immune system as part of normal physiology have been presented, direct evidence to support them is hard to find. Under extreme conditions of chronic stress, the cumulative actions of glucocorticoids on insulin resistance or immunocompromise may indeed seem to be actually damaging. Two well-documented and long recognized situations create huge variation in glucocorticoid secretion. These are the circadian rhythm, and the acute response to mild stress, such as handling, in the rat. Neither of these can be adequately explained by the need for glucocorticoid action, as we currently understand it, particularly on carbohydrate metabolism or on the immune system. Perhaps we should re-examine other targets at the physiological

  10. Gene expression in cortex and hippocampus during acute pneumococcal meningitis

    Directory of Open Access Journals (Sweden)

    Wittwer Matthias

    2006-06-01

    Full Text Available Abstract Background Pneumococcal meningitis is associated with high mortality (~30% and morbidity. Up to 50% of survivors are affected by neurological sequelae due to a wide spectrum of brain injury mainly affecting the cortex and hippocampus. Despite this significant disease burden, the genetic program that regulates the host response leading to brain damage as a consequence of bacterial meningitis is largely unknown. We used an infant rat model of pneumococcal meningitis to assess gene expression profiles in cortex and hippocampus at 22 and 44 hours after infection and in controls at 22 h after mock-infection with saline. To analyze the biological significance of the data generated by Affymetrix DNA microarrays, a bioinformatics pipeline was used combining (i a literature-profiling algorithm to cluster genes based on the vocabulary of abstracts indexed in MEDLINE (NCBI and (ii the self-organizing map (SOM, a clustering technique based on covariance in gene expression kinetics. Results Among 598 genes differentially regulated (change factor ≥ 1.5; p ≤ 0.05, 77% were automatically assigned to one of 11 functional groups with 94% accuracy. SOM disclosed six patterns of expression kinetics. Genes associated with growth control/neuroplasticity, signal transduction, cell death/survival, cytoskeleton, and immunity were generally upregulated. In contrast, genes related to neurotransmission and lipid metabolism were transiently downregulated on the whole. The majority of the genes associated with ionic homeostasis, neurotransmission, signal transduction and lipid metabolism were differentially regulated specifically in the hippocampus. Of the cell death/survival genes found to be continuously upregulated only in hippocampus, the majority are pro-apoptotic, while those continuously upregulated only in cortex are anti-apoptotic. Conclusion Temporal and spatial analysis of gene expression in experimental pneumococcal meningitis identified potential

  11. Spatial audio quality perception (part 1)

    DEFF Research Database (Denmark)

    Conetta, R.; Brookes, T.; Rumsey, F.

    2015-01-01

    Spatial audio processes (SAPs) commonly encountered in consumer audio reproduction systems are known to produce a range of impairments to spatial quality. By way of two listening tests, this paper investigated the degree of degradation of the spatial quality of six 5-channel audio recordings resu...

  12. Spatial audio quality perception (part 1)

    DEFF Research Database (Denmark)

    Conetta, R.; Brookes, T.; Rumsey, F.;

    2015-01-01

    Spatial audio processes (SAPs) commonly encountered in consumer audio reproduction systems are known to produce a range of impairments to spatial quality. By way of two listening tests, this paper investigated the degree of degradation of the spatial quality of six 5-channel audio recordings resu...

  13. Prenatal cocaine exposure decreases parvalbumin-immunoreactive neurons and GABA-to-projection neuron ratio in the medial prefrontal cortex.

    Science.gov (United States)

    McCarthy, Deirdre M; Bhide, Pradeep G

    2012-01-01

    Cocaine abuse during pregnancy produces harmful effects not only on the mother but also on the unborn child. The neurotransmitters dopamine and serotonin are known as the principal targets of the action of cocaine in the fetal and postnatal brain. However, recent evidence suggests that cocaine can impair cerebral cortical GABA neuron development and function. We sought to analyze the effects of prenatal cocaine exposure on the number and distribution of GABA and projection neurons (inhibitory interneurons and excitatory output neurons, respectively) in the mouse cerebral cortex. We found that the prenatal cocaine exposure decreased GABA neuron numbers and GABA-to-projection neuron ratio in the medial prefrontal cortex of 60-day-old mice. The neighboring prefrontal cortex did not show significant changes in either of these measures. However, there was a significant increase in projection neuron numbers in the prefrontal cortex but not in the medial prefrontal cortex. Thus, the effects of cocaine on GABA and projection neurons appear to be cortical region specific. The population of parvalbumin-immunoreactive GABA neurons was decreased in the medial prefrontal cortex following the prenatal cocaine exposure. The cocaine exposure also delayed the developmental decline in the volume of the medial prefrontal cortex. Thus, prenatal cocaine exposure produced persisting and region-specific effects on cortical cytoarchitecture and impaired the physiological balance between excitatory and inhibitory neurotransmission. These structural changes may underlie the electrophysiological and behavioral effects of prenatal cocaine exposure observed in animal models and human subjects.

  14. TMS investigations into the task-dependent functional interplay between human posterior parietal and motor cortex.

    Science.gov (United States)

    Koch, Giacomo; Rothwell, John C

    2009-09-14

    Transcranial magnetic stimulation (TMS) can be used in two different ways to investigate the contribution of cortical areas involved in grasp/reach movements in humans. It can produce "virtual lesions" that interfere with activity in particular cortical areas at specific times during a task, or it can be used in a twin coil design to test the excitability of cortical projections to M1 at different times during a task. The former method has described how cortical structures such as the ventral premotor cortex (PMv), dorsal premotor cortex (PMd) and the anterior intraparietal sulcus (aIPS) are important for specific aspects of reaching, grasping and lifting objects. In the latter method, a conditioning stimulus (CS) is first used to activate putative pathways to the motor cortex from, for example, posterior parietal cortex (PPC) or PMd, while a second, test stimulus (TS), delivered over the primary motor cortex a few ms later probes any changes in excitability that are produced by the input. Thus changes in the effectiveness of the conditioning pulse give an indication of how the excitability of the connection changes over time and during a specific task. Here we review studies describing the time course of operation of parallel intracortical circuits and cortico-cortical connections between the PMd, PMv, PPC and M1, thus demonstrating that functional interplay between these areas and the primary motor cortices is not fixed, but can change in a highly task-, condition- and time-dependent manner.

  15. Spatial distribution

    DEFF Research Database (Denmark)

    Borregaard, Michael Krabbe; Hendrichsen, Ditte Katrine; Nachman, Gøsta Støger

    2008-01-01

    Living organisms are distributed over the entire surface of the planet. The distribution of the individuals of each species is not random; on the contrary, they are strongly dependent on the biology and ecology of the species, and vary over different spatial scale. The structure of whole...... populations reflects the location and fragmentation pattern of the habitat types preferred by the species, and the complex dynamics of migration, colonization, and population growth taking place over the landscape. Within these, individuals are distributed among each other in regular or clumped patterns......, depending on the nature of intraspecific interactions between them: while the individuals of some species repel each other and partition the available area, others form groups of varying size, determined by the fitness of each group member. The spatial distribution pattern of individuals again strongly...

  16. 轻型脑外伤对大鼠空间学习记忆的影响及机制研究%Mild Traumatic Brain Injury Produces Spatial Learning and Memory Deficits in Rats

    Institute of Scientific and Technical Information of China (English)

    许宏武; 谢泽宇; 林岚; 庄泽锐; 林欣鹏; 周文

    2012-01-01

    目的:探讨轻型脑外伤对大鼠空间学习记忆功能的影响及可能的机制.方法:成年SD大鼠120只,雌雄各半,随机分为雌性对照组、雌性实验组、雄性对照组及雄性实验组,各30只;实验组建立侧位液压冲击轻型颅脑外伤模型;术后8d,水迷宫测试大鼠学习记忆能力;水迷宫测试结束后,放射免疫法检测血清皮质醇(COR)水平;免疫组化法检测海马脑源性神经营养因子(BDNF)及酪氨酸激酶受体(TrkB)的表达.结果:水迷宫定位航行实验第4天,同性别大鼠实验组逃逸潜伏期较对照组显著延长(P<0.01);空间探索实验中,同性别大鼠实验组寻找平台潜伏期长于对照组(P<0.05),穿越平台次数少于对照组(P<0.05);同性别大鼠实验组血清COR水平显著高于对照组(P<0.01),海马BDNF及TrkB平均灰度值均低于对照组(P<0.05).结论:轻型脑外伤导致大鼠认知功能缺损,可能与海马BDNF及TtkB表达减少,BDNF-TrkB通路受损有关.%Objective: To investigate the effect of mild brain trauma on the spatial learning and memory of rats and its underlying mechanism. Methods; One-hundred and twenty SD rats (bisexual each half) were randomly divided into four groups; female control group, female experimental group, male control group and male experimental group (n=30, respectively). All rats in the experimental groups were developed a lateral fluid percussion model of mild brain trauma. Morris water maze (MWM) test was used to assess the spatial learning and memory of rats at day 8 after operation. Serum COR levels were determined by using a standard radioimmunoassay kit and the expressions of brain-derived neurotrophic factor (BDNF) and tyrosine protein kinase B (TrkB) in hippocampus were measured by immunoreactivity quantitative analysis after MWM test. Results; At the 4th day of navigation task, the escape latency of rats in the experimental groups were significantly longer than those in the

  17. Center-surround antagonism in spatial vision: retinal or cortical locus?

    Science.gov (United States)

    Westheimer, Gerald

    2004-01-01

    Mach and Hering had early advanced a model of spatial visual processing featuring an antagonistic interaction between adjoining areas in the visual field. Spatial opponency was one of the first findings when single-unit studies of the retina were begun. Not long afterwards psychophysical experiments revealed a center-surround organization closely matching that found in the mammalian retina. It hinged on the demonstration of reduction of sensitivity in a small patch of the visual field when its surround was changed from dark to bright. Because such patterns inevitably produce borders, well-known phenomena of border interaction could be seen as providing alternative explanations, whose substrate would most likely be in the visual cortex. These competing viewpoints are discussed especially as they pertain to the recent demonstration of spatial differences in the center/surround organization between the normal and affected eyes of amblyopes. To the extent that most findings favor a retinal site for the psychophysically measured antagonism, and that evidence is accumulating for a direct effect on the mammalian retina of stimulus manipulation during visual development, the difference in spatial parameters of center/surround antagonism in amblyopia suggests that the dysfunction in amblyopia begins already in the retina.

  18. Quantification of the adrenal cortex hormones with radioimmunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Badillo A, V.; Carrera D, A. A.; Ibarra M, C. M., E-mail: vbadillocren@hotmail.co [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2010-10-15

    The pathologies of the adrenal cortex -adrenal insufficiency and Cushing syndrome- have their origin on the deficit or hypersecretion of some of the hormones that are secreted by the adrenal cortex, which is divided in three zones anatomically defined: the external zone, also called the zona glomerulosa, which is the main production site of aldosterone and mineralocorticoids; the internal zone, or zona reticularis, that produces androgens; and the external zone, or zone 1 orticotrop, which is responsible for producing glucocorticoids. In this work, a quantitative analysis of those hormones and their pathologic trigger was made; the quantification was made in the laboratory by means of highly sensitive and specific techniques, in this case, the radioimmunoassay, in which a radioisotope I-125 is used. This technique is based on the biochemical bond-type reaction, because it requires of a substance called the linker, which bonds to another called ligand. This reaction is also known as antigen-antibody (Ag-Ab), where the results of the reaction will depend on the quantity of antigen in the sample and on its affinity for the antibody. In this work, a 56 patients (of which 13 were men and 43 women) study was made. The cortisol, the ACTH, the androsterone and the DHEA values were very elevated in the majority of the cases corresponding to women, predominating cortisol; while in men, a notorious elevation of the 17 {alpha}-OH-PRG and of the DHEA-SO{sub 4} was observed. Based on that, we can conclude that 51 of them did not have mayor complications, because they just went to the laboratory once, while the remaining 5 had a medical monitoring, and they visited the laboratory more than one occasion, tell about a difficulty on their improvement. According to the results, an approximate relation of 8:2 women:men, respectively, becomes clear to the hormonal pathologies of the adrenal cortex. (Author)

  19. Cytoarchitecture and probability maps of the human medial orbitofrontal cortex.

    Science.gov (United States)

    Henssen, Anton; Zilles, Karl; Palomero-Gallagher, Nicola; Schleicher, Axel; Mohlberg, Hartmut; Gerboga, Fatma; Eickhoff, Simon B; Bludau, Sebastian; Amunts, Katrin

    2016-02-01

    Previous architectonical studies of human orbitofrontal cortex (OFC) provided divergent maps regarding number, location, and extent of areas. To solve this controversy, an observer-independent cytoarchitectonical mapping of medial OFC (mOFC) was performed. Borders of cortical areas were detected in histological sections of ten human post-mortem brains using a quantitative, statistically testable method, and their stereotaxic localization and intersubject variability were determined. Three areas were identified: granular Fo1 mainly on the rostral Gyrus rectus and medial of the olfactory sulcus; granular to dysgranular Fo2, mainly on the posterior part of the ventromedial Gyrus rectus and the medial and lateral banks of the olfactory sulcus; granular Fo3 between the olfactory and medial or intermediate orbital sulci. Fo3 was bordered medially by Fo1 and Fo2 and laterally by the lateral OFC (lOFC). A cluster analysis of the cytoarchitectonical features of Fo1-Fo3, subgenual cingulate areas, BA12, lateral and medial areas of the frontopolar cortex, lOFC and areas of Broca's region demonstrated the cytoarchitectonical similarity between the mOFC areas in contrast to all other frontal areas. Probabilistic maps of mOFC areas show a considerable intersubject variability in extent and position in stereotaxic space, and provide spatial templates for anatomical localization of in vivo neuroimaging data via the JuBrain atlas and the Anatomy Toolbox.

  20. [Investigation of the Cerebral Cortex Using Magnetoencephalography(MEG)].

    Science.gov (United States)

    Kakigi, Ryusuke

    2015-04-01

    Cortical neurons are excited by signals from the thalamus that are conducted via thalamocortical fibers. As the cortex receives these signals, electric currents are conducted through the apical dendrites of pyramidal cells in the cerebral cortex. These electric currents generate magnetic fields. These electric and magnetic currents can be recorded by electroencephalography (EEG) and magnetoencephalography (MEG), respectively. The spatial resolution of MEG is higher than that of EEG because magnetic fields, unlike electric fields, are not affected by current conductivity. MEG also has several advantages over functional magnetic resonance imaging (fMRI). It (1) is completely non-invasive; (2) measures neuronal activity rather than blood flow or metabolic changes; (3) has a higher temporal resolution than fMRI on the order of milliseconds; (4) enables the measurement of stimulus-evoked and event-related responses; (5) enables the analysis of frequency (i.e., brain rhythm) response, which means that physiological changes can be analyzed spatiotemporally; and (6) enables the detailed analysis of results from an individual subject, which eliminates the need to average results over several subjects. This latter advantage of MEG therefore enables the analysis of inter-individual differences.

  1. Prefrontal cortex and hippocampus in behavioural flexibility and posttraumatic functional recovery

    DEFF Research Database (Denmark)

    Rytter, Hana Malá; Andersen, Lykke Grønbech; Christensen, Rie Friis

    2015-01-01

    Within one experiment and one T-maze, we examined the consequences of (i) bilateral lesions of the anteromedial prefrontal cortex (PFC), (ii) bilateral transections of the fimbria-fornix (FF), or (iii) combined lesions of both PFC and FF (COMB) on rats' ability to perform reversal or set-shifting......Within one experiment and one T-maze, we examined the consequences of (i) bilateral lesions of the anteromedial prefrontal cortex (PFC), (ii) bilateral transections of the fimbria-fornix (FF), or (iii) combined lesions of both PFC and FF (COMB) on rats' ability to perform reversal or set......-shifting. Postoperatively, the animals were trained to perform a spatial discrimination go-right task. This was followed by (1) a spatial reversal go-left task (reversal learning), or (2) a visual pattern discrimination task (set-shift). Neither single (PFC or FF) lesion nor combined (COMB) lesions affected the animals...

  2. Images of Illusory Motion in Primary Visual Cortex

    DEFF Research Database (Denmark)

    Larsen, Axel; Madsen, Kristoffer; Ellegaard Lund, Torben

    2006-01-01

    Illusory motion can be generated by successively flashing a stationary visual stimulus in two spatial locations separated by several degrees of visual angle. In appropriate conditions, the apparent motion is indistinguishable from real motion: The observer experiences a luminous object traversing...... a continuous path from one stimulus location to the other through intervening positions where no physical stimuli exist. The phenomenon has been extensively investigated for nearly a century but little is known about its neurophysiological foundation. Here we present images of activations in the primary visual...... cortex in response to real and apparent motion. The images show that during apparent motion, a path connecting the cortical representations of the stimulus locations is filled in by activation. The activation along the path of apparent motion is similar to the activation found when a stimulus...

  3. Functional rather than effector-specific organization of human posterior parietal cortex

    OpenAIRE

    Heed, T.; Beurze, S.M.; Toni, I; Roder, B.; Medendorp, Pieter

    2011-01-01

    Neurophysiological and neuroimaging studies have shown that the posterior parietal cortex (PPC) distinguishes between the planning of eye and hand movements. This distinction has usually been interpreted as evidence for a modular, effector-specific organization of this cerebral region. However, the eyes differ markedly from other body parts both in terms of their functional purpose and with regard to the spatial transformations required to plan goal-directed movements. PPC may therefore provi...

  4. Perirhinal cortex and temporal lobe epilepsy

    Directory of Open Access Journals (Sweden)

    Giuseppe eBiagini

    2013-08-01

    Full Text Available The perirhinal cortex – which is interconnected with several limbic structures and is intimately involved in learning and memory - plays major roles in pathological processes such as the kindling phenomenon of epileptogenesis and the spread of limbic seizures. Both features may be relevant to the pathophysiology of mesial temporal lobe epilepsy that represents the most refractory adult form of epilepsy with up to 30% of patients not achieving adequate seizure control. Compared to other limbic structures such as the hippocampus or the entorhinal cortex, the perirhinal area remains understudied and, in particular, detailed information on its dysfunctional characteristics remains scarce; this lack of information may be due to the fact that the perirhinal cortex is not grossly damaged in mesial temporal lobe epilepsy and in models mimicking this epileptic disorder. However, we have recently identified in pilocarpine-treated epileptic rats the presence of selective losses of interneuron subtypes along with increased synaptic excitability. In this review we: (i highlight the fundamental electrophysiological properties of perirhinal cortex neurons; (ii briefly stress the mechanisms underlying epileptiform synchronization in perirhinal cortex networks following epileptogenic pharmacological manipulations; and (iii focus on the changes in neuronal excitability and cytoarchitecture of the perirhinal cortex occurring in the pilocarpine model of mesial temporal lobe epilepsy. Overall, these data indicate that perirhinal cortex networks are hyperexcitable in an animal model of temporal lobe epilepsy, and that this condition is associated with a selective cellular damage that is characterized by an age-dependent sensitivity of interneurons to precipitating injuries, such as status epilepticus.

  5. Cortical depth dependence of the BOLD initial dip and poststimulus undershoot in human visual cortex at 7 Tesla

    NARCIS (Netherlands)

    Siero, JCW; Hendrikse, J; Hoogduin, Hans; Petridou, N; Luijten, Peter; Donahue, Manus J.

    2015-01-01

    PurposeOwing to variability in vascular dynamics across cerebral cortex, blood-oxygenation-level-dependent (BOLD) spatial and temporal characteristics should vary as a function of cortical-depth. Here, the positive response, initial dip (ID), and post-stimulus undershoot (PSU) of the BOLD response i

  6. Dose-dependent effect of donepezil administration on long-term enhancement of visually evoked potentials and cholinergic receptor overexpression in rat visual cortex.

    Science.gov (United States)

    Chamoun, Mira; Groleau, Marianne; Bhat, Menakshi; Vaucher, Elvire

    2016-09-01

    Stimulation of the cholinergic system tightly coupled with periods of visual stimulation boosts the processing of specific visual stimuli via muscarinic and nicotinic receptors in terms of intensity, priority and long-term effect. However, it is not known whether more diffuse pharmacological stimulation with donepezil, a cholinesterase inhibitor, is an efficient tool for enhancing visual processing and perception. The goal of the present study was to potentiate cholinergic transmission with donepezil treatment (0.5 and 1mg/kg) during a 2-week visual training to examine the effect on visually evoked potentials and to profile the expression of cholinergic receptor subtypes. The visual training was performed daily, 10min a day, for 2weeks. One week after the last training session, visual evoked potentials were recorded, or the mRNA expression level of muscarinic (M1-5) and nicotinic (α/β) receptors subunits was determined by quantitative RT-PCR. The visual stimulation coupled with any of the two doses of donepezil produced significant amplitude enhancement of cortical evoked potentials compared to pre-training values. The enhancement induced by the 1mg/kg dose of donepezil was spread to neighboring spatial frequencies, suggesting a better sensitivity near the visual detection threshold. The M3, M4, M5 and α7 receptors mRNA were upregulated in the visual cortex for the higher dose of donepezil but not the lower one, and the receptors expression was stable in the somatosensory (non-visual control) cortex. Therefore, higher levels of acetylcholine within the cortex sustain the increased intensity of the cortical response and trigger the upregulation of cholinergic receptors.

  7. The Spatial Politics of Spatial Representation

    DEFF Research Database (Denmark)

    Olesen, Kristian; Richardson, Tim

    2011-01-01

    This paper explores the interplay between the spatial politics of new governance landscapes and innovations in the use of spatial representations in planning. The central premise is that planning experiments with new relational approaches become enmeshed in spatial politics. The case of strategic...... spatial planning in Denmark reveals how fuzzy spatial representations and relational spatial concepts are being used to depoliticise strategic spatial planning processes and to camouflage spatial politics. The paper concludes that, while relational geography might play an important role in building...... consensus, it plays an equal important role in supporting current neoliberal transformations of strategic spatial planning....

  8. Long timescale fMRI neuronal adaptation effects in human amblyopic cortex.

    Directory of Open Access Journals (Sweden)

    Xingfeng Li

    Full Text Available An investigation of long timescale (5 minutes fMRI neuronal adaptation effects, based on retinotopic mapping and spatial frequency stimuli, is presented in this paper. A hierarchical linear model was developed to quantify the adaptation effects in the visual cortex. The analysis of data involved studying the retinotopic mapping and spatial frequency adaptation effects in the amblyopic cortex. Our results suggest that, firstly, there are many cortical regions, including V1, where neuronal adaptation effects are reduced in the cortex in response to amblyopic eye stimulation. Secondly, our results show the regional contribution is different, and it seems to start from V1 and spread to the extracortex regions. Thirdly, our results show that there is greater adaptation to broadband retinotopic mapping as opposed to narrowband spatial frequency stimulation of the amblyopic eye, and we find significant correlation between fMRI response and the magnitude of the adaptation effect, suggesting that the reduced adaptation may be a consequence of the reduced response to different stimuli reported for amblyopic eyes.

  9. Alpha stimulation of the human parietal cortex attunes tactile perception to external space.

    Science.gov (United States)

    Ruzzoli, Manuela; Soto-Faraco, Salvador

    2014-02-03

    An intriguing question in neuroscience concerns how somatosensory events on the skin are represented in the human brain. Since Head and Holmes' [1] neuropsychological dissociation between localizing touch on the skin and localizing body parts in external space, touch is considered to operate in a variety of spatial reference frames [2]. At least two representations of space are in competition during orienting to touch: a somatotopic one, reflecting the organization of the somatosensory cortex (S1) [3], and a more abstract, external reference frame that factors postural changes in relation to body parts and/or external space [4, 5]. Previous transcranial magnetic stimulation (TMS) studies suggest that the posterior parietal cortex (PPC) plays a key role in supporting representations as well as orienting attention in an external reference frame [4, 6]. Here, we capitalized on the TMS entrainment approach [7, 8], targeting the intraparietal sulcus (IPS). We found that frequency-specific (10 Hz) tuning of the PPC induced spatially specific enhancement of tactile detection that was expressed in an external reference frame. This finding establishes a tight causal link between a concrete form of brain activity (10 Hz oscillation) and a specific type of spatial representation, revealing a fundamental property of how the parietal cortex encodes information.

  10. Deep prepiriform cortex kindling and amygdala interactions.

    Science.gov (United States)

    Zhao, D Y; Moshé, S L

    1987-03-01

    The deep prepiriform cortex (DPC) has been recently suggested to be a crucial epileptogenic site in the rat brain. We investigated the susceptibility of the DPC to the development of electrical kindling as compared to that of the superficial prepiriform cortex (SPC) and amygdala as well as the transfer interactions between the two prepiriform sites and amygdala. Adult rats with electrodes implanted in the right prepiriform cortex (DPC or SPC) and left amygdala were divided into a DPC-amygdala and SPC-amygdala group while a third group consisted of rats with electrodes implanted in the ipsilateral DPC and amygdala. Within each group the rats were initially kindled from one site selected randomly and then rekindled from the other site. Both DPC and SPC were as sensitive to the development of kindling as the amygdala. The behavioral seizures elicited with DPC or SPC primary kindling were identical to those induced by amygdala kindling. Initial DPC kindling facilitated the development of kindling from either ipsilateral or contralateral amygdala with the ipsilateral transfer being significantly more potent than the contralateral. SPC kindling also facilitated the development of contralateral amygdala kindling but was less effective than DPC kindling. On the other hand, amygdala kindling did not facilitate contralateral SPC or DPC kindling although it transferred to the ipsilateral DPC. These results indicate that the prepiriform cortex can be readily kindled but not faster than the amygdala and that there are unequal kindling transfer interactions between prepiriform cortex and amygdala.

  11. Motor cortex neuroplasticity following brachial plexus transfer

    Directory of Open Access Journals (Sweden)

    Stefan eDimou

    2013-08-01

    Full Text Available In the past decade, research has demonstrated that cortical plasticity, once thought only to exist in the early stages of life, does indeed continue on into adulthood. Brain plasticity is now acknowledged as a core principle of brain function and describes the ability of the central nervous system to adapt and modify its structural organization and function as an adaptive response to functional demand. In this clinical case study we describe how we used neuroimaging techniques to observe the functional topographical expansion of a patch of cortex along the sensorimotor cortex of a 27 year-old woman following brachial plexus transfer surgery to re-innervate her left arm. We found bilateral activations present in the thalamus, caudate, insula as well as across the sensorimotor cortex during an elbow flex motor task. In contrast we found less activity in the sensorimotor cortex for a finger tap motor task in addition to activations lateralised to the left inferior frontal gyrus and thalamus and bilaterally for the insula. From a pain perspective the patient who had experienced extensive phantom limb pain before surgery found these sensations were markedly reduced following transfer of the right brachial plexus to the intact left arm. Within the context of this clinical case the results suggest that functional improvements in limb mobility are associated with increased activation in the sensorimotor cortex as well as reduced phantom limb pain.

  12. Input-dependent wave attenuation in a critically-balanced model of cortex.

    Directory of Open Access Journals (Sweden)

    Xiao-Hu Yan

    Full Text Available A number of studies have suggested that many properties of brain activity can be understood in terms of critical systems. However it is still not known how the long-range susceptibilities characteristic of criticality arise in the living brain from its local connectivity structures. Here we prove that a dynamically critically-poised model of cortex acquires an infinitely-long ranged susceptibility in the absence of input. When an input is presented, the susceptibility attenuates exponentially as a function of distance, with an increasing spatial attenuation constant (i.e., decreasing range the larger the input. This is in direct agreement with recent results that show that waves of local field potential activity evoked by single spikes in primary visual cortex of cat and macaque attenuate with a characteristic length that also increases with decreasing contrast of the visual stimulus. A susceptibility that changes spatial range with input strength can be thought to implement an input-dependent spatial integration: when the input is large, no additional evidence is needed in addition to the local input; when the input is weak, evidence needs to be integrated over a larger spatial domain to achieve a decision. Such input-strength-dependent strategies have been demonstrated in visual processing. Our results suggest that input-strength dependent spatial integration may be a natural feature of a critically-balanced cortical network.

  13. Mismatch Receptive Fields in Mouse Visual Cortex.

    Science.gov (United States)

    Zmarz, Pawel; Keller, Georg B

    2016-11-23

    In primary visual cortex, a subset of neurons responds when a particular stimulus is encountered in a certain location in visual space. This activity can be modeled using a visual receptive field. In addition to visually driven activity, there are neurons in visual cortex that integrate visual and motor-related input to signal a mismatch between actual and predicted visual flow. Here we show that these mismatch neurons have receptive fields and signal a local mismatch between actual and predicted visual flow in restricted regions of visual space. These mismatch receptive fields are aligned to the retinotopic map of visual cortex and are similar in size to visual receptive fields. Thus, neurons with mismatch receptive fields signal local deviations of actual visual flow from visual flow predicted based on self-motion and could therefore underlie the detection of objects moving relative to the visual flow caused by self-motion. VIDEO ABSTRACT.

  14. Detecting Cortex Fragments During Bacterial Spore Germination.

    Science.gov (United States)

    Francis, Michael B; Sorg, Joseph A

    2016-06-25

    The process of endospore germination in Clostridium difficile, and other Clostridia, increasingly is being found to differ from the model spore-forming bacterium, Bacillus subtilis. Germination is triggered by small molecule germinants and occurs without the need for macromolecular synthesis. Though differences exist between the mechanisms of spore germination in species of Bacillus and Clostridium, a common requirement is the hydrolysis of the peptidoglycan-like cortex which allows the spore core to swell and rehydrate. After rehydration, metabolism can begin and this, eventually, leads to outgrowth of a vegetative cell. The detection of hydrolyzed cortex fragments during spore germination can be difficult and the modifications to the previously described assays can be confusing or difficult to reproduce. Thus, based on our recent report using this assay, we detail a step-by-step protocol for the colorimetric detection of cortex fragments during bacterial spore germination.

  15. The Age of Human Cerebral Cortex Neurons

    Energy Technology Data Exchange (ETDEWEB)

    Bhardwaj, R D; Curtis, M A; Spalding, K L; Buchholz, B A; Fink, D; Bjork-Eriksson, T; Nordborg, C; Gage, F H; Druid, H; Eriksson, P S; Frisen, J

    2006-04-06

    The traditional static view of the adult mammalian brain has been challenged by the realization of continuous generation of neurons from stem cells. Based mainly on studies in experimental animals, adult neurogenesis may contribute to recovery after brain insults and decreased neurogenesis has been implicated in the pathogenesis of neurological and psychiatric diseases in man. The extent of neurogenesis in the adult human brain has, however, been difficult to establish. We have taken advantage of the integration of {sup 14}C, generated by nuclear bomb tests during the Cold War, in DNA to establish the age of neurons in the major areas of the human cerebral cortex. Together with the analysis of the cortex from patients who received BrdU, which integrates in the DNA of dividing cells, our results demonstrate that whereas non-neuronal cells turn over, neurons in the human cerebral cortex are not generated postnatally at detectable levels, but are as old as the individual.

  16. Goal-directed attention alters the tuning of object-based representations in extrastriate cortex

    Directory of Open Access Journals (Sweden)

    Anthony J.-W. Chen

    2012-06-01

    Full Text Available Humans survive in environments that contain a vast quantity and variety of visual information. All items of perceived visual information must be represented within a limited number of brain networks. The human brain requires mechanisms for selecting only a relevant fraction of perceived information for more in-depth processing, where neural representations of that information may be actively maintained and utilized for goal-directed behavior. Object-based attention is crucial for goal-directed behavior and yet remains poorly understood. Thus, in the study we investigate how neural representations of visual object information are guided by selective attention. The magnitude of activation in human extrastriate cortex has been shown to be modulated by attention; however object-based attention is not likely to be fully explained by a localized gain mechanism. Thus, we measured information coded in spatially distributed patterns of brain activity with fMRI while human participants performed a task requiring selective processing of a relevant visual object category that differed across conditions. Using pattern classification and spatial correlation techniques, we found that the direction of selective attention is implemented as a shift in the tuning of object-based information representations within extrastriate cortex. In contrast, we found that representations within lateral prefrontal cortex coded for the attention condition rather than the concrete representations of object category. In sum, our findings are consistent with a model of object-based selective attention in which representations coded within extrastriate cortex are tuned to favor the representation of goal-relevant information, guided by more abstract representations within lateral prefrontal cortex.

  17. A dendritic mechanism for decoding traveling waves: principles and applications to motor cortex.

    Directory of Open Access Journals (Sweden)

    Stewart Heitmann

    2013-10-01

    Full Text Available Traveling waves of neuronal oscillations have been observed in many cortical regions, including the motor and sensory cortex. Such waves are often modulated in a task-dependent fashion although their precise functional role remains a matter of debate. Here we conjecture that the cortex can utilize the direction and wavelength of traveling waves to encode information. We present a novel neural mechanism by which such information may be decoded by the spatial arrangement of receptors within the dendritic receptor field. In particular, we show how the density distributions of excitatory and inhibitory receptors can combine to act as a spatial filter of wave patterns. The proposed dendritic mechanism ensures that the neuron selectively responds to specific wave patterns, thus constituting a neural basis of pattern decoding. We validate this proposal in the descending motor system, where we model the large receptor fields of the pyramidal tract neurons - the principle outputs of the motor cortex - decoding motor commands encoded in the direction of traveling wave patterns in motor cortex. We use an existing model of field oscillations in motor cortex to investigate how the topology of the pyramidal cell receptor field acts to tune the cells responses to specific oscillatory wave patterns, even when those patterns are highly degraded. The model replicates key findings of the descending motor system during simple motor tasks, including variable interspike intervals and weak corticospinal coherence. By additionally showing how the nature of the wave patterns can be controlled by modulating the topology of local intra-cortical connections, we hence propose a novel integrated neuronal model of encoding and decoding motor commands.

  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. Neural representations of faces and body parts in macaque and human cortex: a comparative FMRI study.

    Science.gov (United States)

    Pinsk, Mark A; Arcaro, Michael; Weiner, Kevin S; Kalkus, Jan F; Inati, Souheil J; Gross, Charles G; Kastner, Sabine

    2009-05-01

    Single-cell studies in the macaque have reported selective neural responses evoked by visual presentations of faces and bodies. Consistent with these findings, functional magnetic resonance imaging studies in humans and monkeys indicate that regions in temporal cortex respond preferentially to faces and bodies. However, it is not clear how these areas correspond across the two species. Here, we directly compared category-selective areas in macaques and humans using virtually identical techniques. In the macaque, several face- and body part-selective areas were found located along the superior temporal sulcus (STS) and middle temporal gyrus (MTG). In the human, similar to previous studies, face-selective areas were found in ventral occipital and temporal cortex and an additional face-selective area was found in the anterior temporal cortex. Face-selective areas were also found in lateral temporal cortex, including the previously reported posterior STS area. Body part-selective areas were identified in the human fusiform gyrus and lateral occipitotemporal cortex. In a first experiment, both monkey and human subjects were presented with pictures of faces, body parts, foods, scenes, and man-made objects, to examine the response profiles of each category-selective area to the five stimulus types. In a second experiment, face processing was examined by presenting upright and inverted faces. By comparing the responses and spatial relationships of the areas, we propose potential correspondences across species. Adjacent and overlapping areas in the macaque anterior STS/MTG responded strongly to both faces and body parts, similar to areas in the human fusiform gyrus and posterior STS. Furthermore, face-selective areas on the ventral bank of the STS/MTG discriminated both upright and inverted faces from objects, similar to areas in the human ventral temporal cortex. Overall, our findings demonstrate commonalities and differences in the wide-scale brain organization between

  20. Inactivation of the anterior cingulate reveals enhanced reliance on cortical networks for remote spatial memory retrieval after sequential memory processing.

    Directory of Open Access Journals (Sweden)

    Brianne C Wartman

    Full Text Available One system consolidation model suggests that as time passes, ensembles of cortical neurons form strong connections to represent remote memories. In this model, the anterior cingulate cortex (ACC serves as a cortical region that represents remote memories. However, there is debate as to whether remote spatial memories go through this systems consolidation process and come to rely on the ACC. The present experiment examined whether increasing the processing demand on the hippocampus, by sequential training on two spatial tasks, would more fully engage the ACC during retrieval of a remote spatial memory. In this scenario, inactivation of the ACC at a remote time point was hypothesized to produce a severe memory deficit if rats had been trained on two, sequential spatial tasks. Rats were trained on a water maze (WM task only or a WM task followed by a radial arm maze task. A WM probe test was given recently or remotely to all rats. Prior to the probe test, rats received an injection of saline or muscimol into the ACC. A subtle deficit in probe performance was found at the remote time point in the group trained on only one spatial task and treated with muscimol. In the group trained on two spatial tasks and treated with muscimol, a subtle deficit in probe performance was noted at the recent time point and a substantial deficit in probe performance was observed at the remote time point. c-Fos labeling in the hippocampus revealed more labeling in the CA1 region in all remotely tested groups than recently tested groups. Findings suggest that spatial remote memories come to rely more fully on the ACC when hippocampal processing requirements are increased. Results also suggest continued involvement of the hippocampus in spatial memory retrieval along with a progressive strengthening of cortical connections as time progresses.

  1. Inactivation of the anterior cingulate reveals enhanced reliance on cortical networks for remote spatial memory retrieval after sequential memory processing.

    Science.gov (United States)

    Wartman, Brianne C; Gabel, Jennifer; Holahan, Matthew R

    2014-01-01

    One system consolidation model suggests that as time passes, ensembles of cortical neurons form strong connections to represent remote memories. In this model, the anterior cingulate cortex (ACC) serves as a cortical region that represents remote memories. However, there is debate as to whether remote spatial memories go through this systems consolidation process and come to rely on the ACC. The present experiment examined whether increasing the processing demand on the hippocampus, by sequential training on two spatial tasks, would more fully engage the ACC during retrieval of a remote spatial memory. In this scenario, inactivation of the ACC at a remote time point was hypothesized to produce a severe memory deficit if rats had been trained on two, sequential spatial tasks. Rats were trained on a water maze (WM) task only or a WM task followed by a radial arm maze task. A WM probe test was given recently or remotely to all rats. Prior to the probe test, rats received an injection of saline or muscimol into the ACC. A subtle deficit in probe performance was found at the remote time point in the group trained on only one spatial task and treated with muscimol. In the group trained on two spatial tasks and treated with muscimol, a subtle deficit in probe performance was noted at the recent time point and a substantial deficit in probe performance was observed at the remote time point. c-Fos labeling in the hippocampus revealed more labeling in the CA1 region in all remotely tested groups than recently tested groups. Findings suggest that spatial remote memories come to rely more fully on the ACC when hippocampal processing requirements are increased. Results also suggest continued involvement of the hippocampus in spatial memory retrieval along with a progressive strengthening of cortical connections as time progresses.

  2. The Anterior Cingulate Cortex and Pain Processing

    Directory of Open Access Journals (Sweden)

    Perry Neil Fuchs

    2014-05-01

    Full Text Available The neural network that contributes to the suffering which accompanies persistent pain states involves a number of brain regions. Of primary interest is the contribution of the cingulate cortex in processing the affective component of pain. The purpose of this review is to summarize recent data obtained using novel behavioral paradigms in animals based on measuring escape and/or avoidance of a noxious stimulus. These paradigms have successfully been used to study the nature of the neuroanatomical and neurochemical contributions of the anterior cingulate cortex to higher order pain processing in rodents.

  3. Coding of movements in the motor cortex.

    Science.gov (United States)

    Georgopoulos, Apostolos P; Carpenter, Adam F

    2015-08-01

    The issue of coding of movement in the motor cortex has recently acquired special significance due to its fundamental importance in neuroprosthetic applications. The challenge of controlling a prosthetic arm by processed motor cortical activity has opened a new era of research in applied medicine but has also provided an 'acid test' for hypotheses regarding coding of movement in the motor cortex. The successful decoding of movement information from the activity of motor cortical cells using their directional tuning and population coding has propelled successful neuroprosthetic applications and, at the same time, asserted the utility of those early discoveries, dating back to the early 1980s.

  4. Postictal inhibition of the somatosensory cortex

    DEFF Research Database (Denmark)

    Beniczky, Sándor; Jovanovic, Marina; Atkins, Mary Doreen

    2011-01-01

    Transient suppression of the motor cortex and of the speech areas cause well-described postictal phenomena following seizures involving the respective cortical areas. Pain is a rare symptom in epileptic seizures. We present a patient with painful tonic seizures in the left leg. The amplitude...... of the cortical component of the somatosensory evoked potential following stimulation of the left tibial nerve was reduced immediately after the seizure. Our findings suggest that the excitability of the sensory cortex is transiently reduced following a seizure involving the somatosensory area....

  5. Functional Zonation of the Adult Mammalian Adrenal Cortex

    Science.gov (United States)

    Vinson, Gavin P.

    2016-01-01

    The standard model of adrenocortical zonation holds that the three main zones, glomerulosa, fasciculata, and reticularis each have a distinct function, producing mineralocorticoids (in fact just aldosterone), glucocorticoids, and androgens respectively. Moreover, each zone has its specific mechanism of regulation, though ACTH has actions throughout. Finally, the cells of the cortex originate from a stem cell population in the outer cortex or capsule, and migrate centripetally, changing their phenotype as they progress through the zones. Recent progress in understanding the development of the gland and the distribution of steroidogenic enzymes, trophic hormone receptors, and other factors suggests that this model needs refinement. Firstly, proliferation can take place throughout the gland, and although the stem cells are certainly located in the periphery, zonal replenishment can take place within zones. Perhaps more importantly, neither the distribution of enzymes nor receptors suggest that the individual zones are necessarily autonomous in their production of steroid. This is particularly true of the glomerulosa, which does not seem to have the full suite of enzymes required for aldosterone biosynthesis. Nor, in the rat anyway, does it express MC2R to account for the response of aldosterone to ACTH. It is known that in development, recruitment of stem cells is stimulated by signals from within the glomerulosa. Furthermore, throughout the cortex local regulatory factors, including cytokines, catecholamines and the tissue renin-angiotensin system, modify and refine the effects of the systemic trophic factors. In these and other ways it more and more appears that the functions of the gland should be viewed as an integrated whole, greater than the sum of its component parts. PMID:27378832

  6. Olfactory consciousness and gamma oscillation couplings across the olfactory bulb, olfactory cortex, and orbitofrontal cortex.

    Science.gov (United States)

    Mori, Kensaku; Manabe, Hiroyuki; Narikiyo, Kimiya; Onisawa, Naomi

    2013-01-01

    The orbitofrontal cortex receives multi-modality sensory inputs, including olfactory input, and is thought to be involved in conscious perception of the olfactory image of objects. Generation of olfactory consciousness may require neuronal circuit mechanisms for the "binding" of distributed neuronal activities, with each constituent neuron representing a specific component of an olfactory percept. The shortest neuronal pathway for odor signals to reach the orbitofrontal cortex is olfactory sensory neuron-olfactory bulb-olfactory cortex-orbitofrontal cortex, but other pathways exist, including transthalamic pathways. Here, we review studies on the structural organization and functional properties of the shortest pathway, and propose a model of neuronal circuit mechanisms underlying the temporal bindings of distributed neuronal activities in the olfactory cortex. We describe a hypothesis that suggests functional roles of gamma oscillations in the bindings. This hypothesis proposes that two types of projection neurons in the olfactory bulb, tufted cells and mitral cells, play distinct functional roles in bindings at neuronal circuits in the olfactory cortex: tufted cells provide specificity-projecting circuits which send odor information with early-onset fast gamma synchronization, while mitral cells give rise to dispersedly-projecting feed-forward binding circuits which transmit the response synchronization timing with later-onset slow gamma synchronization. This hypothesis also suggests a sequence of bindings in the olfactory cortex: a small-scale binding by the early-phase fast gamma synchrony of tufted cell inputs followed by a larger-scale binding due to the later-onset slow gamma synchrony of mitral cell inputs. We discuss that behavioral state, including wakefulness and sleep, regulates gamma oscillation couplings across the olfactory bulb, olfactory cortex, and orbitofrontal cortex.

  7. Olfactory consciousness and gamma oscillation couplings across the olfactory bulb, olfactory cortex and orbitofrontal cortex

    Directory of Open Access Journals (Sweden)

    Kensaku eMori

    2013-10-01

    Full Text Available The orbitofrontal cortex receives multi-modality sensory inputs, including olfactory input, and is thought to be involved in conscious perception of the olfactory image of objects. Generation of olfactory consciousness requires neuronal circuit mechanisms for the ‘binding’ of distributed neuronal activities, with each constituent neuron representing a specific component of an olfactory percept. The shortest neuronal pathway for odor signals to reach the orbitofrontal cortex is olfactory sensory neuron – olfactory bulb – olfactory cortex – orbitofrontal cortex, but other pathways exist, including transthalamic pathways. Here, we review studies on the structural organization and functional properties of the shortest pathway, and propose a model of neuronal circuit mechanisms underlying the temporal bindings of distributed neuronal activities in the olfactory cortex. We describe a hypothesis that suggests functional roles of gamma oscillations in the bindings. This hypothesis proposes that two types of projection neurons in the olfactory bulb, tufted cells and mitral cells, play distinct functional roles in bindings at neuronal circuits in the olfactory cortex: tufted cells provide specificity-projecting circuits which send odor information with early-onset fast gamma synchronization, while mitral cells give rise to dispersedly-projecting feed-forward binding circuits which transmit the response synchronization timing with later-onset slow gamma synchronization. This hypothesis also suggests a sequence of bindings in the olfactory cortex: a small-scale binding by the early-phase fast gamma synchrony of tufted cell inputs followed by a larger-scale binding due to the later-onset slow gamma synchrony of mitral cell inputs. We discuss that behavioral state, including wakefulness and sleep, regulates gamma oscillation couplings across the olfactory bulb, olfactory cortex, and orbitofrontal cortex.

  8. Functional organization of motor cortex of adult macaque monkeys is altered by sensory loss in infancy.

    Science.gov (United States)

    Qi, Hui-Xin; Jain, Neeraj; Collins, Christine E; Lyon, David C; Kaas, Jon H

    2010-02-16

    When somatosensory cortex (S1) is deprived of some of its inputs after section of ascending afferents in the dorsal columns of the spinal cord, it reorganizes to overrepresent the surviving inputs. As somatosensory cortex provides guiding sensory information to motor cortex, such sensory loss and representational reorganization could affect the development of the motor map in primary motor cortex (M1), especially if the sensory loss occurs early in development. To address this possibility, the dorsal columns of the spinal cord were sectioned between cervical levels (C3-5) 3-12 days after birth in five macaque monkeys. After 3-5 years of maturation (young adults), we determined how movements were represented in M1 contralateral to the lesion by using microelectrodes to electrically stimulate sites in M1 to evoke movements. Although the details of the motor maps in these five monkeys varied, the forelimb motor maps were abnormal. The representations of digit movements were reduced and abnormally arranged. Current levels for evoking movements from the forelimb region of M1 were in the normal range, but the lowest mean stimulation thresholds were for wrist or elbow instead of digit movements. Incomplete lesions and bilateral lesions produced fewer abnormalities. The results suggest that the development of normal motor cortex maps in M1 depends on sensory feedback from somatosensory maps.

  9. Insular cortex and neuropsychiatric disorders: a review of recent literature.

    Science.gov (United States)

    Nagai, M; Kishi, K; Kato, S

    2007-09-01

    The insular cortex is located in the centre of the cerebral hemisphere, having connections with the primary and secondary somatosensory areas, anterior cingulate cortex, amygdaloid body, prefrontal cortex, superior temporal gyrus, temporal pole, orbitofrontal cortex, frontal and parietal opercula, primary and association auditory cortices, visual association cortex, olfactory bulb, hippocampus, entorhinal cortex, and motor cortex. Accordingly, dense connections exist among insular cortex neurons. The insular cortex is involved in the processing of visceral sensory, visceral motor, vestibular, attention, pain, emotion, verbal, motor information, inputs related to music and eating, in addition to gustatory, olfactory, visual, auditory, and tactile data. In this article, the literature on the relationship between the insular cortex and neuropsychiatric disorders was summarized following a computer search of the Pub-Med database. Recent neuroimaging data, including voxel based morphometry, PET and fMRI, revealed that the insular cortex was involved in various neuropsychiatric diseases such as mood disorders, panic disorders, PTSD, obsessive-compulsive disorders, eating disorders, and schizophrenia. Investigations of functions and connections of the insular cortex suggest that sensory information including gustatory, olfactory, visual, auditory, and tactile inputs converge on the insular cortex, and that these multimodal sensory information may be integrated there.

  10. Nerve Growth Factor is Primarily Produced by GABAergic Neurons of the Rat Neocortex

    Directory of Open Access Journals (Sweden)

    Jeremy eBiane

    2014-08-01

    Full Text Available Within the cortex, nerve growth factor (NGF mediates the innervation of cholinergic neurons during development, maintains cholinergic corticopetal projections during adulthood and modulates cholinergic function through phenotypic control of the cholinergic gene locus. Recent studies suggest NGF may also play an important role in cortical plasticity in adulthood. Previously, NGF-producing cells have been shown to colocalize with GABAergic cell markers within the hippocampus, striatum, and basal forebrain. Classification of cells producing NGF in the cortex is lacking, however, and cholinergic corticopetal projections have been shown to innervate both pyramidal and GABAergic neurons in the cortex. In order to clarify potential trophic interactions between cortical neurons and cholinergic projections, we used double-fluorescent immunohistochemistry to classify NGF-expressing cells in several cortical regions, including the prefrontal cortex, primary motor cortex, parietal cortex and temporal cortex. Our results show that NGF colocalizes extensively with GABAergic cell markers in all cortical regions examined, with >91% of NGF-labeled cells coexpressing GAD65/67. Conversely, NGF-labeled cells exhibit very little co-localization with the excitatory cell marker CaMKIIα (less than 5% of cells expressing NGF. NGF expression was present in 56% of GAD-labeled cells, suggesting that production is confined to a specific subset of GABAergic neurons. These findings demonstrate that GABAergic cells are the primary source of NGF production in the cortex, and likely support the maintenance and function of basal forebrain cholinergic projections in adulthood.

  11. Higher-order conditioning and the retrosplenial cortex.

    Science.gov (United States)

    Todd, Travis P; Huszár, Roman; DeAngeli, Nicole E; Bucci, David J

    2016-09-01

    The retrosplenial cortex (RSC) is known to contribute to contextual and spatial learning and memory. This is consistent with its well-established connectivity; the RSC is located at the interface of visuo-spatial association areas and the parahippocampal-hippocampal memory system. However, the RSC also contributes to learning and memory for discrete cues. For example, both permanent lesions and temporary inactivation of the RSC have been shown to impair sensory preconditioning, a form of higher-order conditioning. The purpose of the present experiment was to examine the role of the RSC in a closely related higher-order conditioning paradigm: second-order conditioning. Sham and RSC lesioned rats received first-order conditioning in which one visual stimulus (V1) was paired with footshock and one visual stimulus (V2) was not. Following first-order conditioning, one auditory stimulus (A1) was then paired with V1 and a second auditory stimulus (A2) was paired with V2. Although lesions of the RSC impaired the first-order discrimination, they had no impact on the acquisition of second-order conditioning. Thus, the RSC does not appear necessary for acquisition/expression of second-order fear conditioning. The role of the RSC in higher-order conditioning, as well as a possible dissociation from the hippocampus, is discussed.

  12. Categorically distinct types of receptive fields in early visual cortex.

    Science.gov (United States)

    Talebi, Vargha; Baker, Curtis L

    2016-05-01

    In the visual cortex, distinct types of neurons have been identified based on cellular morphology, response to injected current, or expression of specific markers, but neurophysiological studies have revealed visual receptive field (RF) properties that appear to be on a continuum, with only two generally recognized classes: simple and complex. Most previous studies have characterized visual responses of neurons using stereotyped stimuli such as bars, gratings, or white noise and simple system identification approaches (e.g., reverse correlation). Here we estimate visual RF models of cortical neurons using visually rich natural image stimuli and regularized regression system identification methods and characterize their spatial tuning, temporal dynamics, spatiotemporal behavior, and spiking properties. We quantitatively demonstrate the existence of three functionally distinct categories of simple cells, distinguished by their degree of orientation selectivity (isotropic or oriented) and the nature of their output nonlinearity (expansive or compressive). In addition, these three types have differing average values of several other properties. Cells with nonoriented RFs tend to have smaller RFs, shorter response durations, no direction selectivity, and high reliability. Orientation-selective neurons with an expansive output nonlinearity have Gabor-like RFs, lower spontaneous activity and responsivity, and spiking responses with higher sparseness. Oriented RFs with a compressive nonlinearity are spatially nondescript and tend to show longer response latency. Our findings indicate multiple physiologically defined types of RFs beyond the simple/complex dichotomy, suggesting that cortical neurons may have more specialized functional roles rather than lying on a multidimensional continuum.

  13. Coding of relative size in monkey inferotemporal cortex.

    Science.gov (United States)

    Vighneshvel, T; Arun, Sripati P

    2015-04-01

    We seldom mistake a closer object as being larger, even though its retinal image is bigger. One underlying mechanism could be to calculate the size of the retinal image relative to that of another nearby object. Here we set out to investigate whether single neurons in the monkey inferotemporal cortex (IT) are sensitive to the relative size of parts in a display. Each neuron was tested on shapes containing two parts that could be conjoined or spatially separated. Each shape was presented in four versions created by combining the two parts at each of two possible sizes. In this design, neurons sensitive to the absolute size of parts would show the greatest response modulation when both parts are scaled up, whereas neurons encoding relative size would show similar responses. Our main findings are that 1) IT neurons responded similarly to all four versions of a shape, but tuning tended to be more consistent between versions with proportionately scaled parts; 2) in a subpopulation of cells, we observed interactions that resulted in similar responses to proportionately scaled parts; 3) these interactions developed together with sensitivity to absolute size for objects with conjoined parts but developed slightly later for objects with spatially separate parts. Taken together, our results demonstrate for the first time that there is a subpopulation of neurons in IT that encodes the relative size of parts in a display, forming a potential neural substrate for size constancy.

  14. Parietal cortex mediates conscious perception of illusory gestalt.

    Science.gov (United States)

    Zaretskaya, Natalia; Anstis, Stuart; Bartels, Andreas

    2013-01-09

    Grouping local elements into a holistic percept, also known as spatial binding, is crucial for meaningful perception. Previous studies have shown that neurons in early visual areas V1 and V2 can signal complex grouping-related information, such as illusory contours or object-border ownerships. However, relatively little is known about higher-level processes contributing to these signals and mediating global Gestalt perception. We used a novel bistable motion illusion that induced alternating and mutually exclusive vivid conscious experiences of either dynamic illusory contours forming a global Gestalt or moving ungrouped local elements while the visual stimulation remained the same. fMRI in healthy human volunteers revealed that activity fluctuations in two sites of the parietal cortex, the superior parietal lobe and the anterior intraparietal sulcus (aIPS), correlated specifically with the perception of the grouped illusory Gestalt as opposed to perception of ungrouped local elements. We then disturbed activity at these two sites in the same participants using transcranial magnetic stimulation (TMS). TMS over aIPS led to a selective shortening of the duration of the global Gestalt percept, with no effect on that of local elements. The results suggest that aIPS activity is directly involved in the process of spatial binding during effortless viewing in the healthy brain. Conscious perception of global Gestalt is therefore associated with aIPS function, similar to attention and perceptual selection.

  15. New perspectives on the auditory cortex: learning and memory.

    Science.gov (United States)

    Weinberger, Norman M

    2015-01-01

    Primary ("early") sensory cortices have been viewed as stimulus analyzers devoid of function in learning, memory, and cognition. However, studies combining sensory neurophysiology and learning protocols have revealed that associative learning systematically modifies the encoding of stimulus dimensions in the primary auditory cortex (A1) to accentuate behaviorally important sounds. This "representational plasticity" (RP) is manifest at different levels. The sensitivity and selectivity of signal tones increase near threshold, tuning above threshold shifts toward the frequency of acoustic signals, and their area of representation can increase within the tonotopic map of A1. The magnitude of area gain encodes the level of behavioral stimulus importance and serves as a substrate of memory strength. RP has the same characteristics as behavioral memory: it is associative, specific, develops rapidly, consolidates, and can last indefinitely. Pairing tone with stimulation of the cholinergic nucleus basalis induces RP and implants specific behavioral memory, while directly increasing the representational area of a tone in A1 produces matching behavioral memory. Thus, RP satisfies key criteria for serving as a substrate of auditory memory. The findings suggest a basis for posttraumatic stress disorder in abnormally augmented cortical representations and emphasize the need for a new model of the cerebral cortex.

  16. Microglia in the Cerebral Cortex in Autism

    Science.gov (United States)

    Tetreault, Nicole A.; Hakeem, Atiya Y.; Jiang, Sue; Williams, Brian A.; Allman, Elizabeth; Wold, Barbara J.; Allman, John M.

    2012-01-01

    We immunocytochemically identified microglia in fronto-insular (FI) and visual cortex (VC) in autopsy brains of well-phenotyped subjects with autism and matched controls, and stereologically quantified the microglial densities. Densities were determined blind to phenotype using an optical fractionator probe. In FI, individuals with autism had…

  17. Structure of Orbitofrontal Cortex Predicts Social Influence

    DEFF Research Database (Denmark)

    Campbell-Meiklejohn, Daniel; Kanai, Ryota; Bahrami, Bahador

    2012-01-01

    to guide choices and behaviour. These values can often be updated by the expressed preferences of other people as much as by independent experience. In this correspondence, we report a linear relationship between grey matter volume (GM) in a region of lateral orbitofrontal cortex (lOFCGM) and the tendency...

  18. The Piriform Cortex and Human Focal Epilepsy

    Directory of Open Access Journals (Sweden)

    David eVaughan

    2014-12-01

    Full Text Available It is surprising that the piriform cortex, when compared to the hippocampus, has been given relatively little significance in human epilepsy. Like the hippocampus, it has a phylogenetically preserved three-layered cortex that is vulnerable to excitotoxic injury, has broad connections to both limbic and cortical areas, and is highly epileptogenic - being critical to the kindling process. The well-known phenomenon of early olfactory auras in temporal lobe epilepsy highlights its clinical relevance in humans. Perhaps because it is anatomically indistinct and difficult to approach surgically, as it clasps the middle cerebral artery, it has, until now, been understandably neglected. In this review we emphasize how its unique anatomical and functional properties, as primary olfactory cortex, predispose it to involvement in focal epilepsy. From recent convergent findings in human neuroimaging, clinical epileptology and experimental animal models, we make the case that the piriform cortex is likely to play a facilitating and amplifying role in human focal epileptogenesis, and may influence progression to epileptic intractability.

  19. The piriform cortex and human focal epilepsy.

    Science.gov (United States)

    Vaughan, David N; Jackson, Graeme D

    2014-01-01

    It is surprising that the piriform cortex, when compared to the hippocampus, has been given relatively little significance in human epilepsy. Like the hippocampus, it has a phylogenetically preserved three-layered cortex that is vulnerable to excitotoxic injury, has broad connections to both limbic and cortical areas, and is highly epileptogenic - being critical to the kindling process. The well-known phenomenon of early olfactory auras in temporal lobe epilepsy highlights its clinical relevance in human beings. Perhaps because it is anatomically indistinct and difficult to approach surgically, as it clasps the middle cerebral artery, it has, until now, been understandably neglected. In this review, we emphasize how its unique anatomical and functional properties, as primary olfactory cortex, predispose it to involvement in focal epilepsy. From recent convergent findings in human neuroimaging, clinical epileptology, and experimental animal models, we make the case that the piriform cortex is likely to play a facilitating and amplifying role in human focal epileptogenesis, and may influence progression to epileptic intractability.

  20. Contour extracting networks in early extrastriate cortex

    NARCIS (Netherlands)

    Dumoulin, Serge O.; Hess, Robert F.; May, Keith A.; Harvey, Ben M.; Rokers, Bas; Barendregt, Martijn

    2014-01-01

    Neurons in the visual cortex process a local region of visual space, but in order to adequately analyze natural images, neurons need to interact. The notion of an ''association field'' proposes that neurons interact to extract extended contours. Here, we identify the site and properties of contour

  1. Mapping tonotopy in human auditory cortex

    NARCIS (Netherlands)

    van Dijk, Pim; Langers, Dave R M; Moore, BCJ; Patterson, RD; Winter, IM; Carlyon, RP; Gockel, HE

    2013-01-01

    Tonotopy is arguably the most prominent organizational principle in the auditory pathway. Nevertheless, the layout of tonotopic maps in humans is still debated. We present neuroimaging data that robustly identify multiple tonotopic maps in the bilateral auditory cortex. In contrast with some earlier

  2. Hierarchical error representation in medial prefrontal cortex.

    Science.gov (United States)

    Zarr, Noah; Brown, Joshua W

    2016-01-01

    The medial prefrontal cortex (mPFC) is reliably activated by both performance and prediction errors. Error signals have typically been treated as a scalar, and it is unknown to what extent multiple error signals may co-exist within mPFC. Previous studies have shown that lateral frontal cortex (LFC) is arranged in a hierarchy of abstraction, such that more abstract concepts and rules are represented in more anterior cortical regions. Given the close interaction between lateral and medial prefrontal cortex, we explored the hypothesis that mPFC would be organized along a similar rostro-caudal gradient of abstraction, such that more abstract prediction errors are represented further anterior and more concrete errors further posterior. We show that multiple prediction error signals can be found in mPFC, and furthermore, these are arranged in a rostro-caudal gradient of abstraction which parallels that found in LFC. We used a task that requires a three-level hierarchy of rules to be followed, in which the rules changed without warning at each level of the hierarchy. Task feedback indicated which level of the rule hierarchy changed and led to corresponding prediction error signals in mPFC. Moreover, each identified region of mPFC was preferentially functionally connected to correspondingly anterior regions of LFC. These results suggest the presence of a parallel structure between lateral and medial prefrontal cortex, with the medial regions monitoring and evaluating performance based on rules maintained in the corresponding lateral regions.

  3. Contour extracting networks in early extrastriate cortex

    NARCIS (Netherlands)

    Dumoulin, Serge O.; Hess, Robert F.; May, Keith A.; Harvey, Ben M.; Rokers, Bas; Barendregt, Martijn

    2014-01-01

    Neurons in the visual cortex process a local region of visual space, but in order to adequately analyze natural images, neurons need to interact. The notion of an ''association field'' proposes that neurons interact to extract extended contours. Here, we identify the site and properties of contour i

  4. Layer-specific diffusion weighted imaging in human primary visual cortex in vitro.

    Science.gov (United States)

    Kleinnijenhuis, Michiel; Zerbi, Valerio; Küsters, Benno; Slump, Cornelis H; Barth, Markus; van Cappellen van Walsum, Anne-Marie

    2013-10-01

    One of the most prominent characteristics of the human neocortex is its laminated structure. The first person to observe this was Francesco Gennari in the second half the 18th century: in the middle of the depth of primary visual cortex, myelinated fibres are so abundant that he could observe them with bare eyes as a white line. Because of its saliency, the stria of Gennari has a rich history in cyto- and myeloarchitectural research as well as in magnetic resonance (MR) microscopy. In the present paper we show for the first time the layered structure of the human neocortex with ex vivo diffusion weighted imaging (DWI). To achieve the necessary spatial and angular resolution, primary visual cortex samples were scanned on an 11.7 T small-animal MR system to characterize the diffusion properties of the cortical laminae and the stria of Gennari in particular. The results demonstrated that fractional anisotropy varied over cortical depth, showing reduced anisotropy in the stria of Gennari, the inner band of Baillarger and the deepest layer of the cortex. Orientation density functions showed multiple components in the stria of Gennari and deeper layers of the cortex. Potential applications of layer-specific diffusion imaging include characterization of clinical abnormalities, cortical mapping and (intra)cortical tractography. We conclude that future high-resolution in vivo cortical DWI investigations should take into account the layer-specificity of the diffusion properties.

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

    Science.gov (United States)

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

    1997-01-01

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

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

    Science.gov (United States)

    Reithler, Joel; Goebel, Rainer; Ris, Peterjan; Jeurissen, Danique; Reddy, Leila; Claus, Steven; Baayen, Johannes C.; Roelfsema, Pieter R.

    2016-01-01

    Here we report the first quantitative analysis of spiking activity in human early visual cortex. We recorded multi-unit activity from two electrodes in area V2/V3 of a human patient implanted with depth electrodes as part of her treatment for epilepsy. We observed well-localized multi-unit receptive fields with tunings for contrast, orientation, spatial frequency, and size, similar to those reported in the macaque. We also observed pronounced gamma oscillations in the local-field potential that could be used to estimate the underlying spiking response properties. Spiking responses were modulated by visual context and attention. We observed orientation-tuned surround suppression: responses were suppressed by image regions with a uniform orientation and enhanced by orientation contrast. Additionally, responses were enhanced on regions that perceptually segregated from the background, indicating that neurons in the human visual cortex are sensitive to figure-ground structure. Spiking responses were also modulated by object-based attention. When the patient mentally traced a curve through the neurons’ receptive fields, the accompanying shift of attention enhanced neuronal activity. These results demonstrate that the tuning properties of cells in the human early visual cortex are similar to those in the macaque and that responses can be modulated by both contextual factors and behavioral relevance. Our results, therefore, imply that the macaque visual system is an excellent model for the human visual cortex. PMID:27015604

  7. Temporal pattern of acoustic imaging noise asymmetrically modulates activation in the auditory cortex.

    Science.gov (United States)

    Ranaweera, Ruwan D; Kwon, Minseok; Hu, Shuowen; Tamer, Gregory G; Luh, Wen-Ming; Talavage, Thomas M

    2016-01-01

    This study investigated the hemisphere-specific effects of the temporal pattern of imaging related acoustic noise on auditory cortex activation. Hemodynamic responses (HDRs) to five temporal patterns of imaging noise corresponding to noise generated by unique combinations of imaging volume and effective repetition time (TR), were obtained using a stroboscopic event-related paradigm with extra-long (≥27.5 s) TR to minimize inter-acquisition effects. In addition to confirmation that fMRI responses in auditory cortex do not behave in a linear manner, temporal patterns of imaging noise were found to modulate both the shape and spatial extent of hemodynamic responses, with classically non-auditory areas exhibiting responses to longer duration noise conditions. Hemispheric analysis revealed the right primary auditory cortex to be more sensitive than the left to the presence of imaging related acoustic noise. Right primary auditory cortex responses were significantly larger during all the conditions. This asymmetry of response to imaging related acoustic noise could lead to different baseline activation levels during acquisition schemes using short TR, inducing an observed asymmetry in the responses to an intended acoustic stimulus through limitations of dynamic range, rather than due to differences in neuronal processing of the stimulus. These results emphasize the importance of accounting for the temporal pattern of the acoustic noise when comparing findings across different fMRI studies, especially those involving acoustic stimulation.

  8. Long-term potentiation in the neonatal rat barrel cortex in vivo.

    Science.gov (United States)

    An, Shuming; Yang, Jenq-Wei; Sun, Haiyan; Kilb, Werner; Luhmann, Heiko J

    2012-07-11

    Long-term potentiation (LTP) is important for the activity-dependent formation of early cortical circuits. In the neonatal rodent barrel cortex, LTP has been studied only in vitro. We combined voltage-sensitive dye imaging with extracellular multielectrode recordings to study whisker stimulation-induced LTP in the whisker-to-barrel cortex pathway of the neonatal rat barrel cortex in vivo. Single whisker stimulation at 2 Hz for 10 min induced an age-dependent expression of LTP in postnatal day (P) 0 to P14 rats, with the strongest expression of LTP at P3-P5. The magnitude of LTP was largest in the activated barrel-related column, smaller in the surrounding septal region, and no LTP could be observed in the neighboring barrel. Current source density analyses revealed an LTP-associated increase of synaptic current sinks in layer IV/lower layer II/III at P3-P5 and in the cortical plate/upper layer V at P0-P1. Our study demonstrates for the first time an age-dependent and spatially confined LTP in the barrel cortex of the newborn rat in vivo.

  9. Cortex Matures Faster in Youths With Highest IQ

    Science.gov (United States)

    ... Current Issue Past Issues Research News From NIH Cortex Matures Faster in Youths With Highest IQ Past ... scans showed that their brains' outer mantle, or cortex, thickens more rapidly during childhood, reaching its peak ...

  10. Sharp spatially constrained inversion

    DEFF Research Database (Denmark)

    Vignoli, Giulio G.; Fiandaca, Gianluca G.; Christiansen, Anders Vest C A.V.C.;

    2013-01-01

    We present sharp reconstruction of multi-layer models using a spatially constrained inversion with minimum gradient support regularization. In particular, its application to airborne electromagnetic data is discussed. Airborne surveys produce extremely large datasets, traditionally inverted...... by using smoothly varying 1D models. Smoothness is a result of the regularization constraints applied to address the inversion ill-posedness. The standard Occam-type regularized multi-layer inversion produces results where boundaries between layers are smeared. The sharp regularization overcomes......, the results are compatible with the data and, at the same time, favor sharp transitions. The focusing strategy can also be used to constrain the 1D solutions laterally, guaranteeing that lateral sharp transitions are retrieved without losing resolution. By means of real and synthetic datasets, sharp...

  11. [Raman spectra of monkey cerebral cortex tissue].

    Science.gov (United States)

    Zhu, Ji-chun; Guo, Jian-yu; Cai, Wei-ying; Wang, Zu-geng; Sun, Zhen-rong

    2010-01-01

    Monkey cerebral cortex, an important part in the brain to control action and thought activities, is mainly composed of grey matter and nerve cell. In the present paper, the in situ Raman spectra of the cerebral cortex of the birth, teenage and aged monkeys were achieved for the first time. The results show that the Raman spectra for the different age monkey cerebral cortex exhibit most obvious changes in the regions of 1000-1400 and 2800-3000 cm(-1). With monkey growing up, the relative intensities of the Raman bands at 1313 and 2885 cm(-1) mainly assigned to CH2 chain vibrational mode of lipid become stronger and stronger whereas the relative intensities of the Raman bands at 1338 and 2932 cm(-1) mainly assigned to CH3 chain vibrational mode of protein become weaker and weaker. In addition, the two new Raman bands at 1296 and 2850 cm(-1) are only observed in the aged monkey cerebral cortex, therefore, the two bands can be considered as a character or "marker" to differentiate the caducity degree with monkey growth In order to further explore the changes, the relative intensity ratios of the Raman band at 1313 cm(-1) to that at 1338 cm(-1) and the Raman band at 2885 cm(-1) to that at 2 932 cm(-1), I1313/I1338 and I2885/I2932, which are the lipid-to-protein ratios, are introduced to denote the degree of the lipid content. The results show that the relative intensity ratios increase significantly with monkey growth, namely, the lipid content in the cerebral cortex increases greatly with monkey growth. So, the authors can deduce that the overmuch lipid is an important cause to induce the caducity. Therefore, the results will be a powerful assistance and valuable parameter to study the order of life growth and diagnose diseases.

  12. Olfactory consciousness and gamma oscillation couplings across the olfactory bulb, olfactory cortex, and orbitofrontal cortex

    OpenAIRE

    Kensaku eMori; Hiroyuki eManabe; Kimiya eNarikiyo; Naomi eOnisawa

    2013-01-01

    The orbitofrontal cortex receives multi-modality sensory inputs, including olfactory input, and is thought to be involved in conscious perception of the olfactory image of objects. Generation of olfactory consciousness requires neuronal circuit mechanisms for the ‘binding’ of distributed neuronal activities, with each constituent neuron representing a specific component of an olfactory percept. The shortest neuronal pathway for odor signals to reach the orbitofrontal cortex is olfactory senso...

  13. Premotor cortex modulates somatosensory cortex during voluntary movements without proprioceptive feedback

    DEFF Research Database (Denmark)

    Christensen, Mark Schram; Lundbye-Jensen, Jesper; Geertsen, Svend Sparre;

    2007-01-01

    Movement perception relies on sensory feedback, but the involvement of efference copies remains unclear. We investigated movements without proprioceptive feedback using ischemic nerve block during fMRI in healthy humans, and found preserved activation of the primary somatosensory cortex. This act......Movement perception relies on sensory feedback, but the involvement of efference copies remains unclear. We investigated movements without proprioceptive feedback using ischemic nerve block during fMRI in healthy humans, and found preserved activation of the primary somatosensory cortex...

  14. Projection from the perirhinal cortex to the frontal motor cortex in the rat.

    Science.gov (United States)

    Kyuhou, Shin ichi; Gemba, Hisae

    2002-03-01

    Stimulation of the anterior perirhinal cortex (PERa) induced marked surface-negative and depth-positive field potentials in the rat frontal motor cortex (MC) including the rostral and caudal forelimb areas. Injection of biotinylated dextran into the PERa densely labeled axon terminals in the superficial layers of the MC, where vigorous unit responses were evoked after PERa stimulation, indicated that the perirhinal-frontal projection preferentially activates the superficial layer neurons of the MC.

  15. Orbitofrontal cortex, decision-making and drug addiction

    OpenAIRE

    Schoenbaum, Geoffrey; Roesch, Matthew R.; Stalnaker, Thomas A

    2006-01-01

    The orbitofrontal cortex, as a part of prefrontal cortex, is implicated in executive function. However, within this broad region, the orbitofrontal cortex is distinguished by its unique pattern of connections with crucial subcortical associative learning nodes, such as basolateral amygdala and nucleus accumbens. By virtue of these connections, the orbitofrontal cortex is uniquely positioned to use associative information to project into the future, and to use the value of perceived or expecte...

  16. Cellular resolution optical access to brain regions in fissures: imaging medial prefrontal cortex and grid cells in entorhinal cortex.

    Science.gov (United States)

    Low, Ryan J; Gu, Yi; Tank, David W

    2014-12-30

    In vivo two-photon microscopy provides the foundation for an array of powerful techniques for optically measuring and perturbing neural circuits. However, challenging tissue properties and geometry have prevented high-resolution optical access to regions situated within deep fissures. These regions include the medial prefrontal and medial entorhinal cortex (mPFC and MEC), which are of broad scientific and clinical interest. Here, we present a method for in vivo, subcellular resolution optical access to the mPFC and MEC using microprisms inserted into the fissures. We chronically imaged the mPFC and MEC in mice running on a spherical treadmill, using two-photon laser-scanning microscopy and genetically encoded calcium indicators to measure network activity. In the MEC, we imaged grid cells, a widely studied cell type essential to memory and spatial information processing. These cells exhibited spatially modulated activity during navigation in a virtual reality environment. This method should be extendable to other brain regions situated within deep fissures, and opens up these regions for study at cellular resolution in behaving animals using a rapidly expanding palette of optical tools for perturbing and measuring network structure and function.

  17. Spatial neglect, Balint-Homes' and Gerstmann's syndrome, and other spatial disorders.

    Science.gov (United States)

    Vallar, Giuseppe

    2007-07-01

    Brain-damaged patients with lesion or dysfunction involving the parietal cortex may show a variety of neuropsychological impairments involving spatial cognition. The more frequent and disabling deficit is the syndrome of unilateral spatial neglect that, in a nutshell, consists in a bias of spatial representation and attention ipsilateral to of extrapersonal, personal (ie, the body) space, or both, toward the side of the hemispheric lesion. The deficit is more frequent and severe after damage to the right hemisphere, involving particularly the posterior-inferior parietal cortex at the temporo-parietal junction. Damage to these posterior parietal regions may also impair visuospatial short-term memory, which may be associated with and worsen spatial neglect. The neural network supporting spatial representation, attention and short-term memory is, however, more extensive, including the right premotor cortex. Also disorders of drawing and building objects (traditionally termed constructional apraxia) are a frequent indicator of posterior parietal damage in the left and in the right hemispheres. Other less frequent deficits, which, however, have a relevant localizing value, include optic ataxia (namely, the defective reaching of visual objects, in the absence of elementary visuo-motor impairments), which is typically brought about by damage to the superior parietal lobule. Optic ataxia, together with deficits of visual attention, of estimating distances and depth, and with apraxia of gaze, constitutes the severely disabling Balint-Holmes' syndrome, which is typically associated with bilateral posterior parietal and occipital damage. Finally, lesions of the posterior parietal lobule (angular gyrus) in the left hemisphere may bring about a tetrad of symptoms (left-right disorientation, acalculia, finger agnosia, and agraphia) termed Gerstmann's syndrome, that also exists in a developmental form.

  18. Planning Movements in Visual and Physical Space in Monkey Posterior Parietal Cortex.

    Science.gov (United States)

    Kuang, Shenbing; Morel, Pierre; Gail, Alexander

    2016-02-01

    Neurons in the posterior parietal cortex respond selectively for spatial parameters of planned goal-directed movements. Yet, it is still unclear which aspects of the movement the neurons encode: the spatial parameters of the upcoming physical movement (physical goal), or the upcoming visual limb movement (visual goal). To test this, we recorded neuronal activity from the parietal reach region while monkeys planned reaches under either normal or prism-reversed viewing conditions. We found predominant encoding of physical goals while fewer neurons were selective for visual goals during planning. In contrast, local field potentials recorded in the same brain region exhibited predominant visual goal encoding, similar to previous imaging data from humans. The visual goal encoding in individual neurons was neither related to immediate visual input nor to visual memory, but to the future visual movement. Our finding suggests that action planning in parietal cortex is not exclusively a precursor of impending physical movements, as reflected by the predominant physical goal encoding, but also contains spatial kinematic parameters of upcoming visual movement, as reflected by co-existing visual goal encoding in neuronal spiking. The co-existence of visual and physical goals adds a complementary perspective to the current understanding of parietal spatial computations in primates.

  19. Excitotoxic lesions of the infralimbic, but not prelimbic cortex facilitate reversal of appetitive discriminative context conditioning: the role of the infralimbic cortex in context generalisation.

    Directory of Open Access Journals (Sweden)

    Rachel eAshwell

    2014-02-01

    Full Text Available The prelimbic and infralimbic regions of the rat medial prefrontal cortex (mPFC are important components of the limbic cortico-striatal circuit, receiving converging projections from the hippocampus (HPC and amygdala. Mounting evidence points to these regions having opposing roles in the regulation of the expression of contextual fear and context-induced cocaine-seeking. To investigate this functional differentiation in motivated behaviour further, this study employed a novel radial maze task previously shown to be dependent on the integrity of the hippocampus and its functional connection to the nucleus accumbens shell, to investigate the effects of selective excitotoxic lesions of the PL and IL upon the spatial contextual control over reward learning. To this end, rats were trained to develop discriminative responding towards a reward-associated discrete cue presented in three out of six spatial locations (3 arms out of 6 radial maze arms, and to avoid the same discrete cue presented in the other 3 spatial locations. Once acquired, the reward contingencies of the spatial locations were reversed, such that responding to the cue presented in a previously rewarded location is no longer rewarded. Furthermore, the acquisition of spatial learning was probed separately using conditioned place preference and the monitoring of arm selection at the beginning of each training session. Lesions of the PL transiently attenuated the acquisition of the initial cue approach training and spatial learning, while leaving reversal learning intact. In contrast, IL lesions led to a significantly superior performance of spatial context-dependent discriminative cue approach and reversal learning, in the absence of a significant preference for the new reward-associated spatial locations. These results indicate that the PL and IL have functionally dissociative, and potentially opposite roles in the regulation of spatial contextual control over appetitive learning.

  20. Multitarget Multiscale Simulation for Pharmacological Treatment of Dystonia in Motor Cortex

    Science.gov (United States)

    Neymotin, Samuel A.; Dura-Bernal, Salvador; Lakatos, Peter; Sanger, Terence D.; Lytton, William W.

    2016-01-01

    A large number of physiomic pathologies can produce hyperexcitability in cortex. Depending on severity, cortical hyperexcitability may manifest clinically as a hyperkinetic movement disorder or as epilpesy. We focus here on dystonia, a movement disorder that produces involuntary muscle contractions and involves pathology in multiple brain areas including basal ganglia, thalamus, cerebellum, and sensory and motor cortices. Most research in dystonia has focused on basal ganglia, while much pharmacological treatment is provided directly at muscles to prevent contraction. Motor cortex is another potential target for therapy that exhibits pathological dynamics in dystonia, including heightened activity and altered beta oscillations. We developed a multiscale model of primary motor cortex, ranging from molecular, up to cellular, and network levels, containing 1715 compartmental model neurons with multiple ion channels and intracellular molecular dynamics. We wired the model based on electrophysiological data obtained from mouse motor cortex circuit mapping experiments. We used the model to reproduce patterns of heightened activity seen in dystonia by applying independent random variations in parameters to identify pathological parameter sets. These models demonstrated degeneracy, meaning that there were many ways of obtaining the pathological syndrome. There was no single parameter alteration which would consistently distinguish pathological from physiological dynamics. At higher dimensions in parameter space, we were able to use support vector machines to distinguish the two patterns in different regions of space and thereby trace multitarget routes from dystonic to physiological dynamics. These results suggest the use of in silico models for discovery of multitarget drug cocktails. PMID:27378922

  1. Multitarget Multiscale Simulation for Pharmacological Treatment of Dystonia in Motor Cortex.

    Science.gov (United States)

    Neymotin, Samuel A; Dura-Bernal, Salvador; Lakatos, Peter; Sanger, Terence D; Lytton, William W

    2016-01-01

    A large number of physiomic pathologies can produce hyperexcitability in cortex. Depending on severity, cortical hyperexcitability may manifest clinically as a hyperkinetic movement disorder or as epilpesy. We focus here on dystonia, a movement disorder that produces involuntary muscle contractions and involves pathology in multiple brain areas including basal ganglia, thalamus, cerebellum, and sensory and motor cortices. Most research in dystonia has focused on basal ganglia, while much pharmacological treatment is provided directly at muscles to prevent contraction. Motor cortex is another potential target for therapy that exhibits pathological dynamics in dystonia, including heightened activity and altered beta oscillations. We developed a multiscale model of primary motor cortex, ranging from molecular, up to cellular, and network levels, containing 1715 compartmental model neurons with multiple ion channels and intracellular molecular dynamics. We wired the model based on electrophysiological data obtained from mouse motor cortex circuit mapping experiments. We used the model to reproduce patterns of heightened activity seen in dystonia by applying independent random variations in parameters to identify pathological parameter sets. These models demonstrated degeneracy, meaning that there were many ways of obtaining the pathological syndrome. There was no single parameter alteration which would consistently distinguish pathological from physiological dynamics. At higher dimensions in parameter space, we were able to use support vector machines to distinguish the two patterns in different regions of space and thereby trace multitarget routes from dystonic to physiological dynamics. These results suggest the use of in silico models for discovery of multitarget drug cocktails.

  2. Cholecystokinin from the entorhinal cortex enables neural plasticity in the auditory cortex.

    Science.gov (United States)

    Li, Xiao; Yu, Kai; Zhang, Zicong; Sun, Wenjian; Yang, Zhou; Feng, Jingyu; Chen, Xi; Liu, Chun-Hua; Wang, Haitao; Guo, Yi Ping; He, Jufang

    2014-03-01

    Patients with damage to the medial temporal lobe show deficits in forming new declarative memories but can still recall older memories, suggesting that the medial temporal lobe is necessary for encoding memories in the neocortex. Here, we found that cortical projection neurons in the perirhinal and entorhinal cortices were mostly immunopositive for cholecystokinin (CCK). Local infusion of CCK in the auditory cortex of anesthetized rats induced plastic changes that enabled cortical neurons to potentiate their responses or to start responding to an auditory stimulus that was paired with a tone that robustly triggered action potentials. CCK infusion also enabled auditory neurons to start responding to a light stimulus that was paired with a noise burst. In vivo intracellular recordings in the auditory cortex showed that synaptic strength was potentiated after two pairings of presynaptic and postsynaptic activity in the presence of CCK. Infusion of a CCKB antagonist in the auditory cortex prevented the formation of a visuo-auditory association in awake rats. Finally, activation of the entorhinal cortex potentiated neuronal responses in the auditory cortex, which was suppressed by infusion of a CCKB antagonist. Together, these findings suggest that the medial temporal lobe influences neocortical plasticity via CCK-positive cortical projection neurons in the entorhinal cortex.

  3. [Dependence of learning characteristics on visual object properties in Rhesus macaca by bilateral removal of the 7th field of the parietal cortex].

    Science.gov (United States)

    Dudkin, K N; Chueva, I V; Makarov, F N; Orlov, I V

    1998-03-01

    Removal of the rhesus monkey parietal cortex 7th field exerted no effect on learning processes involving visual discrimination of images united in their colour and geometrical form, but the learning of differentiating the spatial information did suffer. The data obtained suggests that, in the process of learning visual differentiation, spatial differentiating signs are formed, the process involving neuronal structures of the 7th field of the inferior cortex. Removal of the 7th field disrupts mechanisms of the body scheme assession and egocentric orientation resulting from visual-vestibular interrelationships.

  4. Topology of ON and OFF inputs in visual cortex enables an invariant columnar architecture.

    Science.gov (United States)

    Lee, Kuo-Sheng; Huang, Xiaoying; Fitzpatrick, David

    2016-05-05

    Circuits in the visual cortex integrate the information derived from separate ON (light-responsive) and OFF (dark-responsive) pathways to construct orderly columnar representations of stimulus orientation and visual space. How this transformation is achieved to meet the specific topographic constraints of each representation remains unclear. Here we report several novel features of ON-OFF convergence visualized by mapping the receptive fields of layer 2/3 neurons in the tree shrew (Tupaia belangeri) visual cortex using two-photon imaging of GCaMP6 calcium signals. We show that the spatially separate ON and OFF subfields of simple cells in layer 2/3 exhibit topologically distinct relationships with the maps of visual space and orientation preference. The centres of OFF subfields for neurons in a given region of cortex are confined to a compact region of visual space and display a smooth visuotopic progression. By contrast, the centres of the ON subfields are distributed over a wider region of visual space, display substantial visuotopic scatter, and have an orientation-specific displacement consistent with orientation preference map structure. As a result, cortical columns exhibit an invariant aggregate receptive field structure: an OFF-dominated central region flanked by ON-dominated subfields. This distinct arrangement of ON and OFF inputs enables continuity in the mapping of both orientation and visual space and the generation of a columnar map of absolute spatial phase.

  5. Context Memory Decline in Middle Aged Adults is Related to Changes in Prefrontal Cortex Function.

    Science.gov (United States)

    Kwon, Diana; Maillet, David; Pasvanis, Stamatoula; Ankudowich, Elizabeth; Grady, Cheryl L; Rajah, M Natasha

    2016-06-01

    The ability to encode and retrieve spatial and temporal contextual details of episodic memories (context memory) begins to decline at midlife. In the current study, event-related fMRI was used to investigate the neural correlates of context memory decline in healthy middle aged adults (MA) compared with young adults (YA). Participants were scanned while performing easy and hard versions of spatial and temporal context memory tasks. Scans were obtained at encoding and retrieval. Significant reductions in context memory retrieval accuracy were observed in MA, compared with YA. The fMRI results revealed that overall, both groups exhibited similar patterns of brain activity in parahippocampal cortex, ventral occipito-temporal regions and prefrontal cortex (PFC) during encoding. In contrast, at retrieval, there were group differences in ventral occipito-temporal and PFC activity, due to these regions being more activated in MA, compared with YA. Furthermore, only in YA, increased encoding activity in ventrolateral PFC, and increased retrieval activity in occipital cortex, predicted increased retrieval accuracy. In MA, increased retrieval activity in anterior PFC predicted increased retrieval accuracy. These results suggest that there are changes in PFC contributions to context memory at midlife.

  6. Spatial working memory in asymptomatic HIV-infected subjects.

    Science.gov (United States)

    Grassi, B; Garghentini, G; Campana, A; Grassi, E; Bertelli, S; Cinque, P; Epifani, M; Lazzarin, A; Scarone, S

    1999-01-01

    Many clinical and research findings converge to indicate that frontal lobe, basal ganglia, and related neuronal connections are primarily involved in human immunodeficiency virus (HIV) infection; frontal lobe, mainly the prefrontal cortex, has a specialized role in working memory processes. This study focused on neuropsychological evaluation of the spatial component of working memory in a sample of 34 asymptomatic HIV-infected subjects as compared with 34 age- and sex-matched seronegative control subjects. A computer-administered test assessing spatial working memory was used for the neuropsychological evaluation. The findings did not show any spatial working memory impairment during the asymptomatic phase of HIV infection.

  7. Sensitive Dependence of Mental Function on Prefrontal Cortex

    OpenAIRE

    Alen J Salerian

    2015-01-01

    This study offers evidence to suggest that both normalcy and psychiatric illness are sensitively dependent upon prefrontal cortex function. In general, the emergence of psychiatric symptoms coincide with diminished influence of prefrontal cortex function. The mediating influence of prefrontal cortex may be independent of molecular and regional brain dysfunctions contributory to psychiatric illness.

  8. The prefrontal cortex and variants of sequential behaviour: indications of functional differentiation between subdivisions of the rat's prefrontal cortex

    DEFF Research Database (Denmark)

    Mogensen, Jesper; Holm, Søren

    1994-01-01

    Neurobiologi, præfrontal cortex, sekventiel adfærd, rotte, adfærdsprogrammering, informationsbearbejdning......Neurobiologi, præfrontal cortex, sekventiel adfærd, rotte, adfærdsprogrammering, informationsbearbejdning...

  9. Brain functional network changes following Prelimbic area inactivation in a spatial memory extinction task.

    Science.gov (United States)

    Méndez-Couz, Marta; Conejo, Nélida M; Vallejo, Guillermo; Arias, Jorge L

    2015-01-01

    Several studies suggest a prefrontal cortex involvement during the acquisition and consolidation of spatial memory, suggesting an active modulating role at late stages of acquisition processes. Recently, we have reported that the prelimbic and infralimbic areas of the prefrontal cortex, among other structures, are also specifically involved in the late phases of spatial memory extinction. This study aimed to evaluate whether the inactivation of the prelimbic area of the prefrontal cortex impaired spatial memory extinction. For this purpose, male Wistar rats were implanted bilaterally with cannulae into the prelimbic region of the prefrontal cortex. Animals were trained during 5 consecutive days in a hidden platform task and tested for reference spatial memory immediately after the last training session. One day after completing the training task, bilateral infusion of the GABAA receptor agonist Muscimol was performed before the extinction protocol was carried out. Additionally, cytochrome c oxidase histochemistry was applied to map the metabolic brain activity related to the spatial memory extinction under prelimbic cortex inactivation. Results show that animals acquired the reference memory task in the water maze, and the extinction task was successfully completed without significant impairment. However, analysis of the functional brain networks involved by cytochrome oxidase activity interregional correlations showed changes in brain networks between the group treated with Muscimol as compared to the saline-treated group, supporting the involvement of the mammillary bodies at a the late stage in the memory extinction process.

  10. Thermodynamic Model of Spatial Memory

    Science.gov (United States)

    Kaufman, Miron; Allen, P.

    1998-03-01

    We develop and test a thermodynamic model of spatial memory. Our model is an application of statistical thermodynamics to cognitive science. It is related to applications of the statistical mechanics framework in parallel distributed processes research. Our macroscopic model allows us to evaluate an entropy associated with spatial memory tasks. We find that older adults exhibit higher levels of entropy than younger adults. Thurstone's Law of Categorical Judgment, according to which the discriminal processes along the psychological continuum produced by presentations of a single stimulus are normally distributed, is explained by using a Hooke spring model of spatial memory. We have also analyzed a nonlinear modification of the ideal spring model of spatial memory. This work is supported by NIH/NIA grant AG09282-06.

  11. Does the Entorhinal Cortex use the Fourier Transform?

    Directory of Open Access Journals (Sweden)

    Jeff eOrchard

    2013-12-01

    Full Text Available Some neurons in the entorhinal cortex (EC fire bursts when the animal occupies locations organized in a hexagonal grid pattern in their spatial environment. Place cells have also been observed, firing bursts only when the animal occupies a particular region of the environment. Both of these types of cells exhibit theta-cycle modulation, firing bursts in the 4-12Hz range. Grid cells fire bursts of action potentials that precess with respect to the theta cycle, a phenomenon dubbed "theta precession". Various models have been proposed to explain these phenomena, and how they relate to navigation. Among the most promising are the oscillator interference models. The bank-of-oscillators model proposed by Welday et al. (2011 exhibits all these features. However, their simulations are based on theoretical oscillators, and not implemented entirely with spiking neurons. We extend their work in a number of ways. First, we place the oscillators in a frequency domain and reformulate the model in terms of Fourier theory. Second, this perspective suggests a division of labour for implementing spatial maps: position, versus map layout. The animal's position is encoded in the phases of the oscillators, while the spatial map shape is encoded implicitly in the weights of the connections between the oscillators and the read-out nodes. Third, it reveals that the oscillator phases all need to conform to a linear relationship across the frequency domain. Fourth, we implement a partial model of the EC using spiking leaky integrate-and-fire (LIF neurons. Fifth, we devise new coupling mechanisms, enlightened by the global phase constraint, and show they are capable of keeping spiking neural oscillators in consistent formation. Our model demonstrates place cells, grid cells, and phase precession. The Fourier model also gives direction for future investigations, such as integrating sensory feedback to combat drift, or explaining why grid cells exist at all.

  12. Spatial Differences and Trend of Emergy Input and Output Indices of Planting Eco-economic System in Major Grain Producing Area: A Case of Hebei Province%粮食主产区种植业生态经济系统投入产出能值空间差异与态势研究——以河北省为例

    Institute of Scientific and Technical Information of China (English)

    王千; 金晓斌; 周寅康

    2012-01-01

    为了揭示粮食主产区种植业生态经济系统能值投入与产出的空间格局特征,促进传统农业向生态型农业转变,论文以国家粮食主产区河北省为研究区域,基于能值理论与空间分析技术,估算了河北省138个县种植业主要投入产出能值指标,从地理学视角上,重点探讨各项能值指标的空间格局差异与分布趋势。研究结果显示:①河北省种植业生态经济系统投入与产出各项能值指标具有明显的空间地域特征,其区域空间分布地理特征差异显著;②能值投入率(EIR)高值区主要分布在石家庄—唐山—秦皇岛地区,平均值15.81,区域差异相对较大;③能值产出率(EYR)高值区主要分布在邢台—邯郸的东南部地区;④县级层次上有机能能值(FR)、能值投入功率(EmPower)、能值产出功率(IEmPower)等种植业投入产出指标在省域范围内呈现出"U"型、倒"U"型、一阶型等空间分布趋势。在科学分析区域植业生态经济系统投入产出能值空间差异特点的基础上,提出了规模化经营、种植业结构科学调整等提高能值利用效率的建议与措施。%In order to reveal the spatial pattern of characteristics of major grain producing areas planting eco-economic system input and output emergy, and promote the changes from traditional agriculture to ecological agriculture, this paper has taken the state grain-producing area--Hebei Province as a study area. Based on emergy theory and spatial analysis techniques, it estimated the main input-output emergy indices of plantation industry of the 138 counties in Hebei Province. From the perspective of geography, this paper focused on the differences of spatial pattern of every emergy indicator and distribution trend. The results show: 1 ) The input and output emergy indi- ces of planting eco-economic system showed significant geographical features. 2) The high value of emergy

  13. Projections from Orbitofrontal Cortex to Anterior Piriform Cortex in the Rat Suggest a Role in Olfactory Information Processing

    OpenAIRE

    ILLIG, KURT R.

    2005-01-01

    The orbitofrontal cortex (OFC) has been characterized as a higher-order, multimodal sensory cortex. Evidence from electrophysiological and behavioral studies in the rat has suggested that OFC plays a role in modulating olfactory guided behavior, and a significant projection to OFC arises from piriform cortex, the traditional primary olfactory cortex. To discern how OFC interacts with primary olfactory structures, the anterograde tracer Phaseolus vulgaris leucoagglutinin was injected into orbi...

  14. Absolute Depth Sensitivity in Cat Primary Visual Cortex under Natural Viewing Conditions.

    Science.gov (United States)

    Pigarev, Ivan N; Levichkina, Ekaterina V

    2016-01-01

    Mechanisms of 3D perception, investigated in many laboratories, have defined depth either relative to the fixation plane or to other objects in the visual scene. It is obvious that for efficient perception of the 3D world, additional mechanisms of depth constancy could operate in the visual system to provide information about absolute distance. Neurons with properties reflecting some features of depth constancy have been described in the parietal and extrastriate occipital cortical areas. It has also been shown that, for some neurons in the visual area V1, responses to stimuli of constant angular size differ at close and remote distances. The present study was designed to investigate whether, in natural free gaze viewing conditions, neurons tuned to absolute depths can be found in the primary visual cortex (area V1). Single-unit extracellular activity was recorded from the visual cortex of waking cats sitting on a trolley in front of a large screen. The trolley was slowly approaching the visual scene, which consisted of stationary sinusoidal gratings of optimal orientation rear-projected over the whole surface of the screen. Each neuron was tested with two gratings, with spatial frequency of one grating being twice as high as that of the other. Assuming that a cell is tuned to a spatial frequency, its maximum response to the grating with a spatial frequency twice as high should be shifted to a distance half way closer to the screen in order to attain the same size of retinal projection. For hypothetical neurons selective to absolute depth, location of the maximum response should remain at the same distance irrespective of the type of stimulus. It was found that about 20% of neurons in our experimental paradigm demonstrated sensitivity to particular distances independently of the spatial frequencies of the gratings. We interpret these findings as an indication of the use of absolute depth information in the primary visual cortex.

  15. Disrupted MEK/ERK signaling in the medial orbital cortex and dorsal endopiriform nuclei of the prefrontal cortex in a chronic restraint stress mouse model of depression.

    Science.gov (United States)

    Leem, Yea-Hyun; Yoon, Sang-Sun; Kim, Yu-Han; Jo, Sangmee Ahn

    2014-09-19

    Depression is one of the most prevalent mental illnesses, and causes a constant feeling of sadness and lose of interest, which often leads to suicide. Evidence suggests that depression is associated with aberrant MEK/ERK signaling. However, studies on MEK/ERK signaling in depression have only been done in a few brain regions, such as the hippocampus and mesolimbic reward pathways. Recent studies also implicate the involvement of the prefrontal cortex in depression. Thus, we examined the changes in MEK/ERK signaling in subregions of the prefrontal cortex of C57BL/6 mice by immunohistochemistry using phospho-MEK1/2 (Ser 217/221) and ERK1/2 (Thr202/Tyr204) antibodies. Mice were subjected to 21 consecutive days of restraint stress (for 2h daily), and depression-like behavior was evaluated using a sociability test and tail suspension test. The antidepressant, imipramine (20mg/kg) was injected intraperitoneally 30min before restraint stress exposure. Chronic/repeated restraint stress produced depressive-like behavior, such as increased social avoidance in the social interaction test, and enhanced immobility time in the tail suspension test. This depressive behavior was ameliorated by imipramine. The behavioral changes well corresponded to a decrease in MEK/ERK immunoreactivity in the medial orbital (MO) cortex and dorsal endopiriform nuclei (DEn), which was averted by imipramine, but not in cingulate, prelimbic, infralimbic, and motor cortex. These results suggest that MEK/ERK signaling is disrupted in the DEn and MO subregions of the prefrontal cortex in the depressive phenotype, and that blocking a decrease in activated MEK/ERK is inherent to the antidepressant imipramine response.

  16. Stimulus-entrained oscillatory activity propagates as waves from area 18 to 17 in cat visual cortex.

    Directory of Open Access Journals (Sweden)

    Lian Zheng

    Full Text Available Previous studies in cat visual cortex reported that area 18 can actively drive neurons in area 17 through cortico-cortical projections. However, the dynamics of such cortico-cortical interaction remains unclear. Here we used multielectrode arrays to examine the spatiotemporal pattern of neuronal activity in cat visual cortex across the 17/18 border. We found that full-field contrast reversal gratings evoked oscillatory wave activity propagating from area 18 to 17. The wave direction was independent of the grating orientation, and could not be accounted for by the spatial distribution of receptive field latencies, suggesting that the waves are largely mediated by intrinsic connections in the cortex. Different from the evoked waves, spontaneous waves propagated along both directions across the 17/18 border. Together, our results suggest that visual stimulation may enhance the flow of information from area 18 to 17.

  17. 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.

  18. High-intensity erotic visual stimuli de-activate the primary visual cortex in women.

    Science.gov (United States)

    Huynh, Hieu K; Beers, Caroline; Willemsen, Antoon; Lont, Erna; Laan, Ellen; Dierckx, Rudi; Jansen, Monique; Sand, Michael; Weijmar Schultz, Willibrord; Holstege, Gert

    2012-06-01

    The primary visual cortex, Brodmann's area (BA 17), plays a vital role in basic survival mechanisms in humans. In most neuro-imaging studies in which the volunteers have to watch pictures or movies, the primary visual cortex is similarly activated independent of the content of the pictures or movies. However, in case the volunteers perform demanding non-visual tasks, the primary visual cortex becomes de-activated, although the amount of incoming visual sensory information is the same. Do low- and high-intensity erotic movies, compared to neutral movies, produce similar de-activation of the primary visual cortex? Brain activation/de-activation was studied by Positron Emission Tomography scanning of the brains of 12 healthy heterosexual premenopausal women, aged 18-47, who watched neutral, low- and high-intensity erotic film segments. We measured differences in regional cerebral blood flow (rCBF) in the primary visual cortex during watching neutral, low-intensity erotic, and high-intensity erotic film segments. Watching high-intensity erotic, but not low-intensity erotic movies, compared to neutral movies resulted in strong de-activation of the primary (BA 17) and adjoining parts of the secondary visual cortex. The strong de-activation during watching high-intensity erotic film might represent compensation for the increased blood supply in the brain regions involved in sexual arousal, also because high-intensity erotic movies do not require precise scanning of the visual field, because the impact is clear to the observer. © 2012 International Society for Sexual Medicine.

  19. Modeling and optoelectronic realization of an artificial cortex

    Science.gov (United States)

    Pashaie, Ramin

    Cortex, the outermost layer of the cerebrum, is recognized as the most developed part of the brain. It is believed that the higher-level functionality of the brain, the operations such as perception, cognition, and learning of both static and dynamic sensory information, originates from the dynamics of the massively interconnected gray cells of cortex. Because of the compact three-dimensional architecture of this biological computational paradigm, realization of bio-inspired machines that imitate such functionalities, including all the cellular details, is prohibitively difficult even if we consider the available nano-fabrication technologies. Based on this logical deduction, instead of considering each single neuron, an intriguing conjecture is to build aggregate level models that mimic the behavior of a population of neurons with collective emergent properties. In our approach, which is presented in this dissertation, cortex is assumed to be a composition of a sequence of discernable interconnected cortical patches. Each concerned patch is a network of asymmetrically coupled complex processing elements whose dynamics contain not only fixed-point and periodic attractors but also bifurcation and chaos. Dynamics of the complex processing elements, in this dissertation, is mathematically modeled by a slight modification of the time evolution of netlets adapted from computational neuroscience. Regarding this modification, the dynamics of a netlet is approximated by that of a quadratic return map. Studying the previous experimental observations demonstrates that a smart way of coupling such processing units is to couple them through their bifurcation parameters. Putting all pieces of this puzzle together, we model each cortical patch by a network of parametrically coupled quadratic return maps. Our simulations prove the ability of this network to emulate many salient features of cortical information processing, such as clustering, classification, generation of sparse

  20. Distinct Neural Substrates for Maintaining Locations and Spatial Relations in Working Memory

    Directory of Open Access Journals (Sweden)

    Kara J Blacker

    2016-11-01

    Full Text Available Previous work has demonstrated a distinction between maintenance of two types of spatial information in working memory (WM: spatial locations and spatial relations. While a body of work has investigated the neural mechanisms of sensory-based information like spatial locations, little is known about how spatial relations are maintained in WM. In two experiments, we used fMRI to investigate the involvement of early visual cortex in the maintenance of spatial relations in WM. In both experiments, we found less quadrant-specific BOLD activity in visual cortex when a single spatial relation, compared to a single spatial location, was held in WM. Also across both experiments, we found a consistent set of brain regions that were differentially activated during maintenance of locations versus relations. Maintaining a location, compared to a relation, was associated with greater activity in typical spatial WM regions like posterior parietal cortex and prefrontal regions. Whereas maintaining a relation, compared to a location, was associated with greater activity in the parahippocampal gyrus and precuneus/retrosplenial cortex. Further, in Experiment 2 we manipulated WM load and included trials where participants had to maintain three spatial locations or relations. Under this high load condition, the regions sensitive to locations versus relations were somewhat different than under low load. We also identified regions that were sensitive to load specifically for location or relation maintenance, as well as overlapping regions sensitive to load more generally. These results suggest that the neural substrates underlying WM maintenance of spatial locations and relations are distinct from one another and that the neural representations of these distinct types of spatial information change with load.

  1. Distinct Neural Substrates for Maintaining Locations and Spatial Relations in Working Memory

    Science.gov (United States)

    Blacker, Kara J.; Courtney, Susan M.

    2016-01-01

    Previous work has demonstrated a distinction between maintenance of two types of spatial information in working memory (WM): spatial locations and spatial relations. While a body of work has investigated the neural mechanisms of sensory-based information like spatial locations, little is known about how spatial relations are maintained in WM. In two experiments, we used fMRI to investigate the involvement of early visual cortex in the maintenance of spatial relations in WM. In both experiments, we found less quadrant-specific BOLD activity in visual cortex when a single spatial relation, compared to a single spatial location, was held in WM. Also across both experiments, we found a consistent set of brain regions that were differentially activated during maintenance of locations vs. relations. Maintaining a location, compared to a relation, was associated with greater activity in typical spatial WM regions like posterior parietal cortex and prefrontal regions. Whereas maintaining a relation, compared to a location, was associated with greater activity in the parahippocampal gyrus and precuneus/retrosplenial cortex. Further, in Experiment 2 we manipulated WM load and included trials where participants had to maintain three spatial locations or relations. Under this high load condition, the regions sensitive to locations vs. relations were somewhat different than under low load. We also identified regions that were sensitive to load specifically for location or relation maintenance, as well as overlapping regions sensitive to load more generally. These results suggest that the neural substrates underlying WM maintenance of spatial locations and relations are distinct from one another and that the neural representations of these distinct types of spatial information change with load. PMID:27932963

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

    Science.gov (United States)

    Maloney, Ryan T

    2015-01-01

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

  3. Functional organization of human intraparietal and frontal cortex for attending, looking, and pointing

    Science.gov (United States)

    Astafiev, Serguei V.; Shulman, Gordon L.; Stanley, Christine M.; Snyder, Abraham Z.; Van Essen, David C.; Corbetta, Maurizio

    2003-01-01

    We studied the functional organization of human posterior parietal and frontal cortex using functional magnetic resonance imaging (fMRI) to map preparatory signals for attending, looking, and pointing to a peripheral visual location. The human frontal eye field and two separate regions in the intraparietal sulcus were similarly recruited in all conditions, suggesting an attentional role that generalizes across response effectors. However, the preparation of a pointing movement selectively activated a different group of regions, suggesting a stronger role in motor planning. These regions were lateralized to the left hemisphere, activated by preparation of movements of either hand, and included the inferior and superior parietal lobule, precuneus, and posterior superior temporal sulcus, plus the dorsal premotor and anterior cingulate cortex anteriorly. Surface-based registration of macaque cortical areas onto the map of fMRI responses suggests a relatively good spatial correspondence between human and macaque parietal areas. In contrast, large interspecies differences were noted in the topography of frontal areas.

  4. Time-compressed preplay of anticipated events in human primary visual cortex.

    Science.gov (United States)

    Ekman, Matthias; Kok, Peter; de Lange, Floris P

    2017-05-23

    Perception is guided by the anticipation of future events. It has been hypothesized that this process may be implemented by pattern completion in early visual cortex, in which a stimulus sequence is recreated after only a subset of the visual input is provided. Here we test this hypothesis using ultra-fast functional magnetic resonance imaging to measure BOLD activity at precisely defined receptive field locations in visual cortex (V1) of human volunteers. We find that after familiarizing subjects with a spatial sequence, flashing only the starting point of the sequence triggers an activity wave in V1 that resembles the full stimulus sequence. This preplay activity is temporally compressed compared to the actual stimulus sequence and remains present even when attention is diverted from the stimulus sequence. Preplay might therefore constitute an automatic prediction mechanism for temporal sequences in V1.

  5. Children’s spatial thinking: Does talk about the spatial world matter?

    Science.gov (United States)

    Pruden, Shannon M.; Levine, Susan C.; Huttenlocher, Janellen

    2012-01-01

    In this paper we examine the relations between parent spatial language input, children’s own production of spatial language, and children’s later spatial abilities. Using a longitudinal study design, we coded the use of spatial language (i.e., words describing the spatial features and properties of objects; e.g., big, tall, circle, curvy, edge) from child age 14 to 46 months in a diverse sample of 52 parent-child dyads interacting in their home settings. These same children were given three non-verbal spatial tasks, items from a Spatial Transformation task (Levine et al., 1999), the Block Design subtest from the WPPSI-III (Wechsler, 2002), and items on the Spatial Analogies subtest from Primary Test of Cognitive Skills (Huttenlocher & Levine, 1990) at 54 months of age. We find that parents vary widely in the amount of spatial language they use with their children during everyday interactions. This variability in spatial language input, in turn, predicts the amount of spatial language children produce, controlling for overall parent language input. Furthermore, children who produce more spatial language are more likely to perform better on spatial problem solving tasks at a later age. PMID:22010900

  6. Social distance evaluation in human parietal cortex.

    Science.gov (United States)

    Yamakawa, Yoshinori; Kanai, Ryota; Matsumura, Michikazu; Naito, Eiichi

    2009-01-01

    Across cultures, social relationships are often thought of, described, and acted out in terms of physical space (e.g. "close friends" "high lord"). Does this cognitive mapping of social concepts arise from shared brain resources for processing social and physical relationships? Using fMRI, we found that the tasks of evaluating social compatibility and of evaluating physical distances engage a common brain substrate in the parietal cortex. The present study shows the possibility of an analytic brain mechanism to process and represent complex networks of social relationships. Given parietal cortex's known role in constructing egocentric maps of physical space, our present findings may help to explain the linguistic, psychological and behavioural links between social and physical space.

  7. Determining physical properties of the cell cortex

    CERN Document Server

    Saha, A; Behrndt, M; Heisenberg, C -P; Jülicher, F; Grill, S W

    2015-01-01

    Actin and myosin assemble into a thin layer of a highly dynamic network underneath the membrane of eukaryotic cells. This network generates the forces that drive cell and tissue-scale morphogenetic processes. The effective material properties of this active network determine large-scale deformations and other morphogenetic events. For example,the characteristic time of stress relaxation (the Maxwell time)in the actomyosin sets the time scale of large-scale deformation of the cortex. Similarly, the characteristic length of stress propagation (the hydrodynamic length) sets the length scale of slow deformations, and a large hydrodynamic length is a prerequisite for long-ranged cortical flows. Here we introduce a method to determine physical parameters of the actomyosin cortical layer (in vivo). For this we investigate the relaxation dynamics of the cortex in response to laser ablation in the one-cell-stage {\\it C. elegans} embryo and in the gastrulating zebrafish embryo. These responses can be interpreted using ...

  8. Apraxia, pantomime and the parietal cortex

    Directory of Open Access Journals (Sweden)

    E. Niessen

    2014-01-01

    In contrast to previous suggestions, current analyses show that both lesion and functional studies support the notion of a left-hemispheric fronto-(temporal-parietal network underlying pantomiming object use. Furthermore, our review demonstrates that the left parietal cortex plays a key role in pantomime-related processes. More specifically, stringently controlled fMRI-studies suggest that in addition to storing motor schemas, left parietal cortex is also involved in activating these motor schemas in the context of pantomiming object use. In addition to inherent differences between structural and functional imaging studies and consistent with the dedifferentiation hypothesis, the age difference between young healthy subjects (typically included in functional imaging studies and elderly neurological patients (typically included in structural lesion studies may well contribute to the finding of a more distributed representation of pantomiming within the motor-dominant left hemisphere in the elderly.

  9. Effects of aging on motor cortex excitability.

    Science.gov (United States)

    Oliviero, A; Profice, P; Tonali, P A; Pilato, F; Saturno, E; Dileone, M; Ranieri, F; Di Lazzaro, V

    2006-05-01

    To determine whether aging is associated with changes in excitability of the cerebral cortex, we evaluated the excitability of the motor cortex with transcranial magnetic stimulation (TMS). We compared TMS related measures obtained in a group of young people with those of a group of old people. Motor evoked potential (MEP) amplitude was significantly smaller in older than in younger controls (1.3+/-0.8 mV versus 2.7+/-1.1 mV; p<0.0071). Mean cortical silent period (CSP) duration was shorter in older than in younger controls (87+/-29 ms versus 147+/-39 ms; p<0.0071). SP duration/MEP amplitude ratios were similar in both groups. Our results are consistent with an impaired efficiency of some intracortical circuits in old age.

  10. Lesions of either anterior orbitofrontal cortex or ventrolateral prefrontal cortex in marmoset monkeys heighten innate fear and attenuate active coping behaviors to predator threat

    Science.gov (United States)

    Shiba, Yoshiro; Kim, Charissa; Santangelo, Andrea M.; Roberts, Angela C.

    2015-01-01

    The ventral prefrontal cortex is an integral part of the neural circuitry that is dysregulated in mood and anxiety disorders. However, the contribution of its distinct sub-regions to the regulation of negative emotion are poorly understood. Recently we implicated both the ventrolateral prefrontal cortex (vlPFC) and anterior orbitofrontal cortex (antOFC) in the regulation of conditioned fear and anxiety responses to a social stimulus, i.e., human intruder, in the marmoset monkey. In the present study we extend our investigations to determine the role of these two regions in regulating innate responses and coping strategies to a predator stimulus, i.e., a model snake. Both the vlPFC and antOFC lesioned groups exhibited enhanced anxiety-related responses to the snake in comparison to controls. Both groups also showed a reduction in active coping behavior. These results indicate that the vlPFC and antOFC contribute independently to the regulation of both innate fear and, as previously reported, conditioned fear, and highlight the importance of these regions in producing stimulus-appropriate coping responses. The finding that dysregulation in two distinct prefrontal regions produces the apparently similar behavioral phenotype of heightened negative emotion provides insight into the varied etiology that may underlie this symptom across a wide variety of neuropsychiatric conditions with implications for personalized treatment strategies. PMID:25653599

  11. Cytoarchitecture of the human cerebral cortex: MR microscopy of excised specimens at 9.4 Tesla.

    Science.gov (United States)

    Fatterpekar, Girish M; Naidich, Thomas P; Delman, Bradley N; Aguinaldo, Juan G; Gultekin, S Humayun; Sherwood, Chet C; Hof, Patrick R; Drayer, Burton P; Fayad, Zahi A

    2002-09-01

    The laminar patterns displayed by MR microscopy (MRM) form one basis for the classification of the cytoarchitectonic areas (Brodmann areas). It is plausible that in the future MRM may depict Brodmann areas directly, and not only by inference from gross anatomic location. Our purpose was to depict the laminar cytoarchitecture of excised, formalin-fixed specimens of human cerebral cortex by use of 9.4-T MR and to correlate MR images with histologic stains of the same sections. Formalin-fixed samples of human sensory isocortex (calcarine, Heschl's, and somatosensory cortices), motor isocortex (hand motor area of M1), polar isocortex (frontal pole), allocortex (hippocampal formation), and transitional periallocortex (retrosplenial cortex) were studied by MRM at 9.4 T with intermediate-weighted pulse sequences for a total overnight acquisition time of 14 hours 17 minutes for each specimen. The same samples were then histologically analyzed to confirm the MR identification of the cortical layers. Curves representing the change in MR signal intensity across the cortex were generated to display the signal intensity profiles for each type of cortex. High-field-strength MR imaging at a spatial resolution of 78 x 78 x 500 micro m resolves the horizontal lamination of isocortex, allocortex, and periallocortex and displays specific intracortical structures such as the external band of Baillarger. The signal intensity profiles demonstrate the greatest hypointensity at the sites of maximum myelin concentration and maximum cell density and show gradations of signal intensity inversely proportional to varying cell density. MRM at 9.4 T depicts important aspects of the cytoarchitecture of normal formalin-fixed human cortex.

  12. Unexpected novelty and familiarity orienting responses in lateral parietal cortex during recognition judgment.

    Science.gov (United States)

    Jaeger, Antonio; Konkel, Alex; Dobbins, Ian G

    2013-05-01

    The role of lateral parietal cortex during recognition memory is heavily debated. We examined parietal activation during an Explicit Memory Cueing recognition paradigm that biases participants towards expecting novel or familiar stimuli on a trial-by-trial basis using anticipatory cues ("Likely Old", "Likely New"), compared to trials with neutral cues ("????"). Three qualitatively distinct patterns were observed in the left lateral parietal cortex. An unexpected novelty response occurred in left anterior intraparietal cortex (IPS)/post-central gyrus (PoCG) in which greater activation was observed for new vs. old materials following the "Likely Old" cue, but not following the "Likely New" cue. In contrast, anterior angular gyrus demonstrated an unexpected familiarity response with greater activation for old vs. new materials following the "Likely New" cue, but not the "Likely Old" cue. Thus these two regions demonstrated increased responses that were selective for either new or old materials respectively, but only when they were unexpected. In contrast, a mid IPS area demonstrated greater response for whichever class of memoranda was unanticipated given the cue condition (an unexpected memory response). Analogous response patterns in regions outside of parietal cortex, and the results of a resting state connectivity analysis, suggested these three response patterns were associated with visuo-spatial orienting following unexpected novelty, source monitoring operations following unexpected familiarity, and general executive control processes following violated expectations. These findings support a Memory Orienting Model of the left lateral parietal cortex in which the region is linked to the investigation of unexpected novelty or familiarity in the environment.

  13. Precision mapping of the vibrissa representation within murine primary somatosensory cortex.

    Science.gov (United States)

    Knutsen, Per M; Mateo, Celine; Kleinfeld, David

    2016-10-05

    The ability to form an accurate map of sensory input to the brain is an essential aspect of interpreting functional brain signals. Here, we consider the somatotopic map of vibrissa-based touch in the primary somatosensory (vS1) cortex of mice. The vibrissae are represented by a Manhattan-like grid of columnar structures that are separated by inter-digitating septa. The development, dynamics and plasticity of this organization is widely used as a model system. Yet, the exact anatomical position of this organization within the vS1 cortex varies between individual mice. Targeting of a particular column in vivo therefore requires prior mapping of the activated cortical region, for instance by imaging the evoked intrinsic optical signal (eIOS) during vibrissa stimulation. Here, we describe a procedure for constructing a complete somatotopic map of the vibrissa representation in the vS1 cortex using eIOS. This enables precise targeting of individual cortical columns. We found, using C57BL/6 mice, that although the precise location of the columnar field varies between animals, the relative spatial arrangement of the columns is highly preserved. This finding enables us to construct a canonical somatotopic map of the vibrissae in the vS1 cortex. In particular, the position of any column, in absolute anatomical coordinates, can be established with near certainty when the functional representations in the vS1 cortex for as few as two vibrissae have been mapped with eIOS.This article is part of the themed issue 'Interpreting BOLD: a dialogue between cognitive and cellular neuroscience'. © 2016 The Author(s).

  14. Architecture of the Entorhinal Cortex A Review of Entorhinal Anatomy in Rodents with Some Comparative Notes

    Directory of Open Access Journals (Sweden)

    Menno P. Witter

    2017-06-01

    Full Text Available The entorhinal cortex (EC is the major input and output structure of the hippocampal formation, forming the nodal point in cortico-hippocampal circuits. Different division schemes including two or many more subdivisions have been proposed, but here we will argue that subdividing EC into two components, the lateral EC (LEC and medial EC (MEC might suffice to describe the functional architecture of EC. This subdivision then leads to an anatomical interpretation of the different phenotypes of LEC and MEC. First, we will briefly summarize the cytoarchitectonic differences and differences in hippocampal projection patterns on which the subdivision between LEC and MEC traditionally is based and provide a short comparative perspective. Second, we focus on main differences in cortical connectivity, leading to the conclusion that the apparent differences may well correlate with the functional differences. Cortical connectivity of MEC is features interactions with areas such as the presubiculum, parasubiculum, retrosplenial cortex (RSC and postrhinal cortex, all areas that are considered to belong to the “spatial processing domain” of the cortex. In contrast, LEC is strongly connected with olfactory areas, insular, medial- and orbitofrontal areas and perirhinal cortex. These areas are likely more involved in processing of object information, attention and motivation. Third, we will compare the intrinsic networks involving principal- and inter-neurons in LEC and MEC. Together, these observations suggest that the different phenotypes of both EC subdivisions likely depend on the combination of intrinsic organization and specific sets of inputs. We further suggest a reappraisal of the notion of EC as a layered input-output structure for the hippocampal formation.

  15. Orbitofrontal Cortex, Associative Learning, and Expectancies

    Science.gov (United States)

    Schoenbaum, Geoffrey; Roesch, Matthew

    2009-01-01

    Orbitofrontal cortex is characterized by its unique pattern of connections with subcortical areas, such as basolateral amygdala. Here we distinguish between the critical role of these areas in associative learning and the pivotal contribution of OFC to the manipulation of this information to control behavior. This contribution reflects the ability of OFC to signal the desirability of expected outcomes, which requires the integration of associative information with information concerning internal states and goals in representational memory. PMID:16129393

  16. Cone inputs to murine striate cortex

    Directory of Open Access Journals (Sweden)

    Gouras Peter

    2008-11-01

    Full Text Available Abstract Background We have recorded responses from single neurons in murine visual cortex to determine the effectiveness of the input from the two murine cone photoreceptor mechanisms and whether there is any unique selectivity for cone inputs at this higher region of the visual system that would support the possibility of colour vision in mice. Each eye was stimulated by diffuse light, either 370 (strong stimulus for the ultra-violet (UV cone opsin or 505 nm (exclusively stimulating the middle wavelength sensitive (M cone opsin, obtained from light emitting diodes (LEDs in the presence of a strong adapting light that suppressed the responses of rods. Results Single cells responded to these diffuse stimuli in all areas of striate cortex. Two types of responsive cells were encountered. One type (135/323 – 42% had little to no spontaneous activity and responded at either the on and/or the off phase of the light stimulus with a few impulses often of relatively large amplitude. A second type (166/323 – 51% had spontaneous activity and responded tonically to light stimuli with impulses often of small amplitude. Most of the cells responded similarly to both spectral stimuli. A few (18/323 – 6% responded strongly or exclusively to one or the other spectral stimulus and rarely in a spectrally opponent manner. Conclusion Most cells in murine striate cortex receive excitatory inputs from both UV- and M-cones. A small fraction shows either strong selectivity for one or the other cone mechanism and occasionally cone opponent responses. Cells that could underlie chromatic contrast detection are present but extremely rare in murine striate cortex.

  17. The role of prefrontal cortex in psychopathy

    OpenAIRE

    Koenigs, Michael

    2012-01-01

    Psychopathy is a personality disorder characterized by remorseless and impulsive antisocial behavior. Given the significant societal costs of the recidivistic criminal activity associated with the disorder, there is a pressing need for more effective treatment strategies, and hence, a better understanding of the psychobiological mechanisms underlying the disorder. The prefrontal cortex (PFC) is likely to play an important role in psychopathy. In particular, the ventromedial and anterior cingu...

  18. Impact of blindness onset on the functional organization and the connectivity of the occipital cortex.

    Science.gov (United States)

    Collignon, Olivier; Dormal, Giulia; Albouy, Geneviève; Vandewalle, Gilles; Voss, Patrice; Phillips, Christophe; Lepore, Franco

    2013-09-01

    Contrasting the impact of congenital versus late-onset acquired blindness provides a unique model to probe how experience at different developmental periods shapes the functional organization of the occipital cortex. We used functional magnetic resonance imaging to characterize brain activations of congenitally blind, late-onset blind and two groups of sighted control individuals while they processed either the pitch or the spatial attributes of sounds. Whereas both blind groups recruited occipital regions for sound processing, activity in bilateral cuneus was only apparent in the congenitally blind, highlighting the existence of region-specific critical periods for crossmodal plasticity. Most importantly, the preferential activation of the right dorsal stream (middle occipital gyrus and cuneus) for the spatial processing of sounds was only observed in the congenitally blind. This demonstrates that vision has to be lost during an early sensitive period in order to transfer its functional specialization for space processing toward a non-visual modality. We then used a combination of dynamic causal modelling with Bayesian model selection to demonstrate that auditory-driven activity in primary visual cortex is better explained by direct connections with primary auditory cortex in the congenitally blind whereas it relies more on feedback inputs from parietal regions in the late-onset blind group. Taken together, these results demonstrate the crucial role of the developmental period of visual deprivation in (re)shaping the functional architecture and the connectivity of the occipital cortex. Such findings are clinically important now that a growing number of medical interventions may restore vision after a period of visual deprivation.

  19. Neuropeptide S overcomes short term memory deficit induced by sleep restriction by increasing prefrontal cortex activity.

    Science.gov (United States)

    Thomasson, Julien; Canini, Frédéric; Poly-Thomasson, Betty; Trousselard, Marion; Granon, Sylvie; Chauveau, Frédéric

    2017-09-20

    Sleep restriction (SR) impairs short term memory (STM) that might be related to different processes. Neuropeptide S (NPS), an endogenous neuropeptide that improves short term memory, activates arousal and decreases anxiety is likely to counteract the SR-induced impairment of STM. The objective of the present study was to find common cerebral pathways in sleep restriction and NPS action in order to ultimately antagonize SR effect on memory. The STM was assessed using a spontaneous spatial alternation task in a T-maze. C57-Bl/6J male mice were distributed in 4 groups according to treatment (0.1nmol of NPS or vehicle intracerebroventricular injection) and to 20h-SR. Immediately after behavioural testing, regional c-fos immunohistochemistry was performed and used as a neural activation marker for spatial short term memory (prefrontal cortex, dorsal hippocampus) and emotional reactivity (basolateral amygdala and ventral hippocampus). Anxiety-like behaviour was assessed using elevated-plus maze task. Results showed that SR impaired short term memory performance and decreased neuronal activation in cingular cortex.NPS injection overcame SR-induced STM deficits and increased neuronal activation in infralimbic cortex. SR spared anxiety-like behavior in the elevated-plus maze. Neural activation in basolateral nucleus of amygdala and ventral hippocampus were not changed after SR.In conclusion, the present study shows that NPS overcomes SR-induced STM deficits by increasing prefrontal cortex activation independently of anxiety-like behaviour. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  20. Handbook of Spatial Statistics

    CERN Document Server

    Gelfand, Alan E

    2010-01-01

    Offers an introduction detailing the evolution of the field of spatial statistics. This title focuses on the three main branches of spatial statistics: continuous spatial variation (point referenced data); discrete spatial variation, including lattice and areal unit data; and, spatial point patterns.

  1. Specialized elements of orbitofrontal cortex in primates.

    Science.gov (United States)

    Barbas, Helen

    2007-12-01

    The orbitofrontal cortex is associated with encoding the significance of stimuli within an emotional context, and its connections can be understood in this light. This large cortical region is architectonically heterogeneous, but its connections and functions can be summarized by a broad grouping of areas by cortical type into posterior and anterior sectors. The posterior (limbic) orbitofrontal region is composed of agranular and dysgranular-type cortices and has unique connections with primary olfactory areas and rich connections with high-order sensory association cortices. Posterior orbitofrontal areas are further distinguished by dense and distinct patterns of connections with the amygdala and memory-related anterior temporal lobe structures that may convey signals about emotional import and their memory. The special sets of connections suggest that the posterior orbitofrontal cortex is the primary region for the perception of emotions. In contrast to orbitofrontal areas, posterior medial prefrontal areas in the anterior cingulate are not multi-modal, but have strong connections with auditory association cortices, brain stem vocalization, and autonomic structures, in pathways that may mediate emotional communication and autonomic activation in emotional arousal. Posterior orbitofrontal areas communicate with anterior orbitofrontal areas and, through feedback projections, with lateral prefrontal and other cortices, suggesting a sequence of information processing for emotions. Pathology in orbitofrontal cortex may remove feedback input to sensory cortices, dissociating emotional context from sensory content and impairing the ability to interpret events.

  2. Emotion, decision making and the orbitofrontal cortex.

    Science.gov (United States)

    Bechara, A; Damasio, H; Damasio, A R

    2000-03-01

    The somatic marker hypothesis provides a systems-level neuroanatomical and cognitive framework for decision making and the influence on it by emotion. The key idea of this hypothesis is that decision making is a process that is influenced by marker signals that arise in bioregulatory processes, including those that express themselves in emotions and feelings. This influence can occur at multiple levels of operation, some of which occur consciously and some of which occur non-consciously. Here we review studies that confirm various predictions from the hypothesis. The orbitofrontal cortex represents one critical structure in a neural system subserving decision making. Decision making is not mediated by the orbitofrontal cortex alone, but arises from large-scale systems that include other cortical and subcortical components. Such structures include the amygdala, the somatosensory/insular cortices and the peripheral nervous system. Here we focus only on the role of the orbitofrontal cortex in decision making and emotional processing, and the relationship between emotion, decision making and other cognitive functions of the frontal lobe, namely working memory.

  3. Binocular form deprivation influences the visual cortex

    Institute of Scientific and Technical Information of China (English)

    Mingming Liu; Chuanhuang Weng; Hanping Xie; Wei Qin

    2012-01-01

    1a-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors are considered to play a crucial role in synaptic plasticity in the developing visual cortex. In this study, we established a rat model of binocular form deprivation by suturing the rat binocular eyelids before eye-opening at postnatal day 14. During development, the decay time of excitatory postsynaptic currents mediated by 1a-amino-3- hydroxy-5-methyl-4-isoxazolepropionic acid receptors of normal rats became longer after eyeopening; however, the decay time did not change significantly in binocular form deprivation rats. The peak value in the normal group became gradually larger with age, but there was no significant change in the binocular form deprivation group. These findings indicate that binocular form deprivation influences the properties of excitatory postsynaptic currents mediated by β-amino-3- hydroxy-5-methyl-4-isoxazolepropionic acid receptors in the rat visual cortex around the end of the critical period, indicating that form stimulation is associated with the experience-dependent modification of neuronal synapses in the visual cortex.

  4. Rhythmic spontaneous activity in the piriform cortex.

    Science.gov (United States)

    Sanchez-Vives, Maria V; Descalzo, V F; Reig, R; Figueroa, N A; Compte, A; Gallego, R

    2008-05-01

    Slow spontaneous rhythmic activity is generated and propagates in neocortical slices when bathed in an artificial cerebrospinal fluid with ionic concentrations similar to the ones in vivo. This activity is extraordinarily similar to the activation of the cortex in physiological conditions (e.g., slow-wave sleep), thus representing a unique in vitro model to understand how cortical networks maintain and control ongoing activity. Here we have characterized the activity generated in the olfactory or piriform cortex and endopiriform nucleus (piriform network). Because these structures are prone to generate epileptic discharges, it seems critical to understand how they generate and regulate their physiological rhythmic activity. The piriform network gave rise to rhythmic spontaneous activity consisting of a succession of up and down states at an average frequency of 1.8 Hz, qualitatively similar to the corresponding neocortical activity. This activity originated in the deep layers of the piriform network, which displayed higher excitability and denser connectivity. A remarkable difference with neocortical activity was the speed of horizontal propagation (114 mm/s), one order of magnitude faster in the piriform network. Properties of the piriform cortex subserving fast horizontal propagation may underlie the higher vulnerability of this area to epileptic seizures.

  5. Human prefrontal cortex: evolution, development, and pathology.

    Science.gov (United States)

    Teffer, Kate; Semendeferi, Katerina

    2012-01-01

    The prefrontal cortex is critical to many cognitive abilities that are considered particularly human, and forms a large part of a neural system crucial for normal socio-emotional and executive functioning in humans and other primates. In this chapter, we survey the literature regarding prefrontal development and pathology in humans as well as comparative studies of the region in humans and closely related primate species. The prefrontal cortex matures later in development than more caudal regions, and some of its neuronal subpopulations exhibit more complex dendritic arborizations. Comparative work suggests that the human prefrontal cortex differs from that of closely related primate species less in relative size than it does in organization. Specific reorganizational events in neural circuitry may have taken place either as a consequence of adjusting to increases in size or as adaptive responses to specific selection pressures. Living in complex environments has been recognized as a considerable factor in the evolution of primate cognition. Normal frontal lobe development and function are also compromised in several neurological and psychiatric disorders. A phylogenetically recent reorganization of frontal cortical circuitry may have been critical to the emergence of human-specific executive and social-emotional functions, and developmental pathology in these same systems underlies many psychiatric and neurological disorders, including autism and schizophrenia.

  6. An integrator circuit in cerebellar cortex.

    Science.gov (United States)

    Maex, Reinoud; Steuber, Volker

    2013-09-01

    The brain builds dynamic models of the body and the outside world to predict the consequences of actions and stimuli. A well-known example is the oculomotor integrator, which anticipates the position-dependent elasticity forces acting on the eye ball by mathematically integrating over time oculomotor velocity commands. Many models of neural integration have been proposed, based on feedback excitation, lateral inhibition or intrinsic neuronal nonlinearities. We report here that a computational model of the cerebellar cortex, a structure thought to implement dynamic models, reveals a hitherto unrecognized integrator circuit. In this model, comprising Purkinje cells, molecular layer interneurons and parallel fibres, Purkinje cells were able to generate responses lasting more than 10 s, to which both neuronal and network mechanisms contributed. Activation of the somatic fast sodium current by subthreshold voltage fluctuations was able to maintain pulse-evoked graded persistent activity, whereas lateral inhibition among Purkinje cells via recurrent axon collaterals further prolonged the responses to step and sine wave stimulation. The responses of Purkinje cells decayed with a time-constant whose value depended on their baseline spike rate, with integration vanishing at low ( 30 per s). The model predicts that the apparently fast circuit of the cerebellar cortex may control the timing of slow processes without having to rely on sensory feedback. Thus, the cerebellar cortex may contain an adaptive temporal integrator, with the sensitivity of integration to the baseline spike rate offering a potential mechanism of plasticity of the response time-constant.

  7. Hierarchical Bayesian inference in the visual cortex

    Science.gov (United States)

    Lee, Tai Sing; Mumford, David

    2003-07-01

    Traditional views of visual processing suggest that early visual neurons in areas V1 and V2 are static spatiotemporal filters that extract local features from a visual scene. The extracted information is then channeled through a feedforward chain of modules in successively higher visual areas for further analysis. Recent electrophysiological recordings from early visual neurons in awake behaving monkeys reveal that there are many levels of complexity in the information processing of the early visual cortex, as seen in the long-latency responses of its neurons. These new findings suggest that activity in the early visual cortex is tightly coupled and highly interactive with the rest of the visual system. They lead us to propose a new theoretical setting based on the mathematical framework of hierarchical Bayesian inference for reasoning about the visual system. In this framework, the recurrent feedforward/feedback loops in the cortex serve to integrate top-down contextual priors and bottom-up observations so as to implement concurrent probabilistic inference along the visual hierarchy. We suggest that the algorithms of particle filtering and Bayesian-belief propagation might model these interactive cortical computations. We review some recent neurophysiological evidences that support the plausibility of these ideas. 2003 Optical Society of America

  8. Does intrinsic motivation enhance motor cortex excitability?

    Science.gov (United States)

    Radel, Rémi; Pjevac, Dusan; Davranche, Karen; d'Arripe-Longueville, Fabienne; Colson, Serge S; Lapole, Thomas; Gruet, Mathieu

    2016-11-01

    Intrinsic motivation (IM) is often viewed as a spontaneous tendency for action. Recent behavioral and neuroimaging evidence indicate that IM, in comparison to extrinsic motivation (EM), solicits the motor system. Accordingly, we tested whether IM leads to greater excitability of the motor cortex than EM. To test this hypothesis, we used two different tasks to induce the motivational orientation using either words representing each motivational orientation or pictures previously linked to each motivational orientation through associative learning. Single-pulse transcranial magnetic stimulation over the motor cortex was applied when viewing the stimuli. Electromyographic activity was recorded on the contracted first dorsal interosseous muscle. Two indexes of corticospinal excitability (the amplitude of motor-evoked potential and the length of cortical silent period) were obtained through unbiased automatic detection and analyzed using a mixed model that provided both statistical power and a high level of control over all important individual, task, and stimuli characteristics. Across the two tasks and the two indices of corticospinal excitability, the exposure to IM-related stimuli did not lead to a greater corticospinal excitability than EM-related stimuli or than stimuli with no motivational valence (ps > .20). While these results tend to dismiss the advantage of IM at activating the motor cortex, we suggest alternative hypotheses to explain this lack of effect, which deserves further research. © 2016 Society for Psychophysiological Research.

  9. The Spatial Know-How of Graffiti

    Directory of Open Access Journals (Sweden)

    Jannes van Loon

    2015-06-01

    Full Text Available My research interest lies in understand the spatial behaviour of graffiti writers (van Loon, 2014. Although graffiti writers have unique perspectives on urban landscapes that determine where and what type of graffiti they produce, they also have collective or shared senses of place – i.e., a spatial know-how that structures their production (Castree, 2003.

  10. The Spatial Know-How of Graffiti

    Directory of Open Access Journals (Sweden)

    Jannes van Loon

    2016-03-01

    Full Text Available My research interest lies in understand the spatial behaviour of graffiti writers (van Loon, 2014. Although graffiti writers have unique perspectives on urban landscapes that determine where and what type of graffiti they produce, they also have collective or shared senses of place – i.e., a spatial know-how that structures their production (Castree, 2003.

  11. Early exposure to urethane anesthesia: Effects on neuronal activity in the piriform cortex of the developing brain.

    Science.gov (United States)

    Kajiwara, Riichi; Takashima, Ichiro

    2015-07-23

    Exposure to urethane anesthesia reportedly produces selective neuronal cell loss in the piriform cortex of young brains; however, resulting functional deficits have not been investigated. The present study found abnormalities in piriform cortex activity of isolated brains in vitro that were harvested from guinea pigs exposed to urethane anesthesia at 14 days of age. Current source density (CSD) analysis and voltage-sensitive dye (VSD) imaging experiments were conducted 48h after urethane injection. We applied paired-pulse stimulation to the lateral olfactory tract (LOT) and assessed short-interval intra-cortical inhibition in the piriform cortex. CSD analysis revealed that a current sink in layer Ib remained active in response to successive stimuli, with an inter-stimulus interval of 30-60 ms, which was typically strongly inhibited. VSD imaging demonstrated stronger and extended neural activity in the urethane-treated piriform cortex, even in response to a second stimulus delivered in short succession. We identified gamma-aminobutyric acid (GABA) ergic neurons in the piriform cortex of sham and urethane-treated animals and found a decrease in GABA-immunoreactive cell density in the urethane group. These results suggest that urethane exposure induces loss of GABAergic interneurons and a subsequent reduction in paired-pulse inhibition in the immature piriform cortex.

  12. Cortex-M0处理器初探%Cortex-M0 Processor:An Initial Survey

    Institute of Scientific and Technical Information of China (English)

    范云龙; 方安平; 李宁

    2010-01-01

    介绍Cortex-M0处理器的特点;详细分析Cortex-M0处理器的编程模型、存储模型、异常处理和功耗管理,并将Cortex-M0与Cortex-M3和基于8/16位架构的处理器作了对比分析;最后简要介绍Cortex-M0处理器的相关开发工具.

  13. Cortical responses to Mozart's sonata enhance spatial-reasoning ability.

    Science.gov (United States)

    Suda, Miyuki; Morimoto, Kanehisa; Obata, Akiko; Koizumi, Hideaki; Maki, Atsushi

    2008-11-01

    In this study, we examined the effects of Mozart's music on spatial-reasoning ability by near-infrared spectroscopy (NIRS). The subjects comprised five males and five females (aged 25-35 years). They were administered the seven original core subtests of the Japanese version of the Tanaka B-type intelligence test, which includes a spatial-reasoning subtest. We used three different music conditions: Mozart's sonata (K. 448), Beethoven and a silent control condition. Moreover, we used optical topography to assess the effects of music on brain function with a spatial-reasoning subtest. We found that exposure to Mozart's sonata enhanced cognitive performance in intelligence tests when compared with results obtained upon exposure to Beethoven or silence. In addition to the expected temporal cortex activation, we report dramatic results revealing differences in activation in the dorsolateral prefrontal cortex and the occipital cortex, both of which are expected to be important for spatial-temporal reasoning. We suggest the possibility of a direct priming effect being responsible for preferential activation, and open the door to understanding the potential effects of Mozart's music.

  14. Associative Encoding in Anterior Piriform Cortex versus Orbitofrontal Cortex during Odor Discrimination and Reversal Learning

    Science.gov (United States)

    Roesch, Matthew R.; Stalnaker, Thomas A.; Schoenbaum, Geoffrey

    2008-01-01

    Recent proposals have conceptualized piriform cortex as an association cortex, capable of integrating incoming olfactory information with descending input from higher order associative regions such as orbitofrontal cortex (OFC). If true, encoding in piriform cortex should reflect associative features prominent in these areas during associative learning involving olfactory cues. To test this hypothesis, we recorded from neurons in OFC and anatomically related parts of the anterior piriform cortex (APC) in rats, learning and reversing novel odor discriminations. Findings in OFC were similar to what we have reported previously, with nearly all the cue-selective neurons exhibiting substantial plasticity during learning and reversal. Also, many of the cue-selective neurons were originally responsive in anticipation of the outcomes early in learning, thereby providing a single-unit representation of the cue-outcome associations. Some of these features were also evident in firing activity in APC, including some plasticity across learning and reversal. However, APC neurons failed to reverse cue selectivity when the associated outcome was changed, and the cue-selective population did not include neurons that were active prior to outcome delivery. Thus, although representations in APC are substantially more associative than expected in a purely sensory region, they do appear to be somewhat more constrained by the sensory features of the odor cues than representations in downstream areas of OFC. PMID:16699083

  15. Hemispheric asymmetry in cerebrovascular reactivity of the human primary motor cortex: an in vivo study at 7 T.

    Science.gov (United States)

    Driver, Ian D; Andoh, Jamila; Blockley, Nicholas P; Francis, Susan T; Gowland, Penny A; Paus, Tomáš

    2015-05-01

    Current functional MRI (fMRI) approaches assess underlying neuronal activity through monitoring the related local variations in cerebral blood oxygenation, blood volume and blood flow. This vascular response is likely to vary across brain regions and across individuals, depending on the composition of the local vascular bed and on the vascular capacity to dilate. The most widely used technique uses the blood oxygen level dependent (BOLD) fMRI signal, which arises from a complex combination of all of these factors. The model of handedness provides a case where one brain region (dominant motor cortex) is known to have a stronger BOLD response over another (non-dominant motor cortex) during hand motor task performance. We predict that this is accompanied by a higher vascular reactivity in the dominant motor cortex, when compared with the non-dominant motor cortex. Precise measurement of end-tidal CO2 and a novel sinusoidal CO2 respiratory challenge were combined with the high sensitivity and finer spatial resolution available for fMRI at 7 T to measure BOLD cerebrovascular reactivity (CVR) in eight healthy male participants. BOLD CVR was compared between the left (dominant) and right (non-dominant) primary motor cortices of right-handed adults. Hemispheric asymmetry in vascular reactivity was predicted and observed in the primary motor cortex (left CVR = 0.60 ± 0.15%/mm Hg; right CVR = 0.47 ± 0.08%/mm Hg; left CVR > right CVR, P = 0.04), the first reported evidence of such a vascular difference. These findings demonstrate a cerebral vascular asymmetry between the left and right primary motor cortex. The origin of this asymmetry largely arises from the contribution of large draining veins. This work has implications for future motor laterality studies that use BOLD, and it is also suggestive of a vascular plasticity in the human primary motor cortex.

  16. Early and late activity in somatosensory cortex reflects changes in bodily self-consciousness: an evoked potential study.

    Science.gov (United States)

    Aspell, J E; Palluel, E; Blanke, O

    2012-08-02

    How can we investigate the brain mechanisms underlying self-consciousness? Recent behavioural studies on multisensory bodily perception have shown that multisensory conflicts can alter bodily self-consciousness such as in the "full body illusion" (FBI) in which changes in self-identification with a virtual body and tactile perception are induced. Here we investigated whether experimental changes in self-identification during the FBI are accompanied by activity changes in somatosensory cortex by recording somatosensory-evoked potentials (SEPs). To modulate self-identification, participants were filmed by a video camera from behind while their backs were stroked, either synchronously (illusion condition) or asynchronously (control condition) with respect to the stroking seen on their virtual body. Tibial nerve SEPs were recorded during the FBI and analysed using evoked potential (EP) mapping. Tactile mislocalisation was measured using the crossmodal congruency task. SEP mapping revealed five sequential periods of brain activation during the FBI, of which two differed between the illusion condition and the control condition. Activation at 30-50 ms (corresponding to the P40 component) in primary somatosensory cortex was stronger in the illusion condition. A later activation at ∼110-200 ms, likely originating in higher-tier somatosensory regions in parietal cortex, was stronger and lasted longer in the control condition. These data show that changes in bodily self-consciousness modulate activity in primary and higher-tier somatosensory cortex at two distinct processing steps. We argue that early modulations of primary somatosensory cortex may be a consequence of (1) multisensory integration of synchronous vs. asynchronous visuo-tactile stimuli and/or (2) differences in spatial attention (to near or far space) between the conditions. The later activation in higher-tier parietal cortex (and potentially other regions in temporo-parietal and frontal cortex) likely

  17. Spatial Management Areas

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Spatial management files combine all related and relevant spatial management files into an integrated fisheries management file. Overlaps of the redundant spatial...

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

    Directory of Open Access Journals (Sweden)

    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.

  19. Learning Touch Preferences with a Tactile Robot Using Dopamine Modulated STDP in a Model of Insular Cortex

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    Ting-Shuo eChou

    2015-07-01

    Full Text Available Neurorobots enable researchers to study how behaviors are produced by neural mechanisms in an uncertain, noisy, real-world environment. To investigate how the somatosensory system processes noisy, real-world touch inputs, we introduce a neurorobot called CARL-SJR, which has a full-body tactile sensory area. The design of CARL-SJR is such that it encourages people to communicate with it through gentle touch. CARL-SJR provides feedback to users by displaying bright colors on its surface. In the present study, we show that CARL-SJR is capable of learning associations between conditioned stimuli (CS; a color pattern on its surface and unconditioned stimuli (US; a preferred touch pattern by applying a spiking neural network (SNN with neurobiologically inspired plasticity. Specifically, we modeled the primary somatosensory cortex, prefrontal cortex, striatum, and the insular cortex, which is important for hedonic touch, to process noisy data generated directly from CARL-SJR’s tactile sensory area. To facilitate learning, we applied dopamine-modulated Spike Timing Dependent Plasticity (STDP to our simulated prefrontal cortex, striatum and insular cortex. To cope with noisy, varying inputs, the SNN was tuned to produce traveling waves of activity that carried spatiotemporal information. Despite the noisy tactile sensors, spike trains, and variations in subject hand swipes, the learning was quite robust. Further, the plasticity (i.e., STDP in primary somatosensory cortex and insular cortex in the incremental pathway of dopaminergic reward system allowed us to control CARL-SJR’s preference for touch direction without heavily pre-processed inputs. The emerged behaviors we found in this model match animal’s behaviors wherein they prefer touch in particular areas and directions. Thus, the results in this paper could serve as an explanation on the underlying neural mechanisms for developing tactile preferences and hedonic touch.

  20. Detecting physiological systems with laser speckle perfusion imaging of the renal cortex.

    Science.gov (United States)

    Scully, Christopher G; Mitrou, Nicholas; Braam, Branko; Cupples, William A; Chon, Ki H

    2013-06-01

    Laser speckle perfusion imaging (LSPI) has become an increasingly popular technique for monitoring vascular perfusion over a tissue surface. However, few studies have utilized the full range of spatial and temporal information generated by LSPI to monitor spatial properties of physiologically relevant dynamics. In this study, we extend the use of LSPI to analyze renal perfusion dynamics over a spatial surface of ~5 × 7 mm of renal cortex. We identify frequencies related to five physiological systems that induce temporal changes in renal vascular perfusion (cardiac flow pulse, respiratory-induced oscillations, baroreflex components, the myogenic response, and tubuloglomerular feedback) across the imaged surface and compare the results with those obtained from renal blood flow measurements. We find that dynamics supplied from global sources (cardiac, respiration, and baroreflex) present with the same frequency at all locations across the imaged surface, but the local renal autoregulation dynamics can be heterogeneous in their distribution across the surface. Moreover, transfer function analysis with forced blood pressure as the input yields the same information with laser speckle imaging or renal blood flow as the output during control, intrarenal infusion of N(ω)-nitro-L-arginine methyl ester to enhance renal autoregulation, and intrarenal infusion of the rho-kinase inhibitor Y-27632 to inhibit vasomotion. We conclude that LSPI measurements can be used to analyze local as well as global renal perfusion dynamics and to study the properties of physiological systems across the renal cortex.

  1. Face, eye, and body selective responses in fusiform gyrus and adjacent cortex: an intracranial EEG study.

    Directory of Open Access Journals (Sweden)

    Andrew D Engell

    2014-08-01

    Full Text Available Functional MRI (fMRI studies have investigated the degree to which processing of whole faces, face-parts, and bodies are differentially localized within the fusiform gyrus and adjacent ventral occipitotemporal cortex. While some studies have emphasized the spatial differentiation of processing into discrete areas, others have emphasized the overlap of processing and the importance of distributed patterns of activity. Intracranial EEG (iEEG recorded from subdural electrodes provides excellent temporal and spatial resolution of local neural activity, and thus provides an alternative method to fMRI for studying differences and commonalities in face and body processing. In this study we recorded iEEG from 12 patients while they viewed images of novel faces, isolated eyes, headless bodies, and flowers. ERP analysis identified 69 occipitotemporal sites at which there was a face-, eye-, or body-selective response when contrasted to flowers. However, when comparing faces, eyes, and bodies to each other at these sites, we identified only 3 face-specific, 13 eye-specific, and 1 body-specific electrodes. Thus, at the majority of sites, faces, eyes, and bodies evoked similar responses. However, we identified ten locations at which the amplitude of the responses spatially varied across adjacent electrodes, indicating that the configuration of current sources and sinks were different for faces, eyes, and bodies. Our results also demonstrate that eye-sensitive regions are more abundant and more purely selective than face- or body-sensitive regions, particularly in lateral occipitotemporal cortex.

  2. Face, eye, and body selective responses in fusiform gyrus and adjacent cortex: an intracranial EEG study.

    Science.gov (United States)

    Engell, Andrew D; McCarthy, Gregory

    2014-01-01

    Functional MRI (fMRI) studies have investigated the degree to which processing of whole faces, face-parts, and bodies are differentially localized within the fusiform gyrus and adjacent ventral occipitotemporal cortex. While some studies have emphasized the spatial differentiation of processing into discrete areas, others have emphasized the overlap of processing and the importance of distributed patterns of activity. Intracranial EEG (iEEG) recorded from subdural electrodes provides excellent temporal and spatial resolution of local neural activity, and thus provides an alternative method to fMRI for studying differences and commonalities in face and body processing. In this study we recorded iEEG from 12 patients while they viewed images of novel faces, isolated eyes, headless bodies, and flowers. Event-related potential analysis identified 69 occipitotemporal sites at which there was a face-, eye-, or body-selective response when contrasted to flowers. However, when comparing faces, eyes, and bodies to each other at these sites, we identified only 3 face-specific, 13 eye-specific, and 1 body-specific electrodes. Thus, at the majority of sites, faces, eyes, and bodies evoked similar responses. However, we identified ten locations at which the amplitude of the responses spatially varied across adjacent electrodes, indicating that the configuration of current sources and sinks were different for faces, eyes, and bodies. Our results also demonstrate that eye-sensitive regions are more abundant and more purely selective than face- or body-sensitive regions, particularly in lateral occipitotemporal cortex.

  3. The Anterior Prefrontal Cortex and the Hippocampus Are Negatively Correlated during False Memories

    Directory of Open Access Journals (Sweden)

    Brittany M. Jeye

    2017-01-01

    Full Text Available False memories commonly activate the anterior/dorsolateral prefrontal cortex (A/DLPFC and the hippocampus. These regions are assumed to work in concert during false memories, which would predict a positive correlation between the magnitudes of activity in these regions across participants. However, the A/DLPFC may also inhibit the hippocampus, which would predict a negative correlation between the magnitudes of activity in these regions. In the present functional magnetic resonance imaging (fMRI study, during encoding, participants viewed abstract shapes in the left or right visual field. During retrieval, participants classified each old shape as previously in the “left” or “right” visual field followed by an “unsure”–“sure”–“very sure” confidence rating. The contrast of left-hits and left-misses produced two activations in the hippocampus and three activations in the left A/DLPFC. For each participant, activity associated with false memories (right–“left”–“very sure” responses from the two hippocampal regions was plotted as a function of activity in each A/DLPFC region. Across participants, for one region in the left anterior prefrontal cortex, there was a negative correlation between the magnitudes of activity in this region and the hippocampus. This suggests that the anterior prefrontal cortex might inhibit the hippocampus during false memories and that participants engage either the anterior prefrontal cortex or the hippocampus during false memories.

  4. Late emergence of the vibrissa direction selectivity map in the rat barrel cortex.

    Science.gov (United States)

    Kremer, Yves; Léger, Jean-François; Goodman, Dan; Brette, Romain; Bourdieu, Laurent

    2011-07-20

    In the neocortex, neuronal selectivities for multiple sensorimotor modalities are often distributed in topographical maps thought to emerge during a restricted period in early postnatal development. Rodent barrel cortex contains a somatotopic map for vibrissa identity, but the existence of maps representing other tactile features has not been clearly demonstrated. We addressed the issue of the existence in the rat cortex of an intrabarrel map for vibrissa movement direction using in vivo two-photon imaging. We discovered that the emergence of a direction map in rat barrel cortex occurs long after all known critical periods in the somatosensory system. This map is remarkably specific, taking a pinwheel-like form centered near the barrel center and aligned to the barrel cortex somatotopy. We suggest that this map may arise from intracortical mechanisms and demonstrate by simulation that the combination of spike-timing-dependent plasticity at synapses between layer 4 and layer 2/3 and realistic pad stimulation is sufficient to produce such a map. Its late emergence long after other classical maps suggests that experience-dependent map formation and refinement continue throughout adult life.

  5. Molecular networks linked by Moesin drive remodeling of the cell cortex during mitosis

    Science.gov (United States)

    Roubinet, Chantal; Decelle, Barbara; Chicanne, Gaëtan; Dorn, Jonas F.; Payrastre, Bernard; Payre, François; Carreno, Sébastien

    2011-01-01

    The cortical mechanisms that drive the series of mitotic cell shape transformations remain elusive. In this paper, we identify two novel networks that collectively control the dynamic reorganization of the mitotic cortex. We demonstrate that Moesin, an actin/membrane linker, integrates these two networks to synergize the cortical forces that drive mitotic cell shape transformations. We find that the Pp1-87B phosphatase restricts high Moesin activity to early mitosis and down-regulates Moesin at the polar cortex, after anaphase onset. Overactivation of Moesin at the polar cortex impairs cell elongation and thus cytokinesis, whereas a transient recruitment of Moesin is required to retract polar blebs that allow cortical relaxation and dissipation of intracellular pressure. This fine balance of Moesin activity is further adjusted by Skittles and Pten, two enzymes that locally produce phosphoinositol 4,5-bisphosphate and thereby, regulate Moesin cortical association. These complementary pathways provide a spatiotemporal framework to explain how the cell cortex is remodeled throughout cell division. PMID:21969469

  6. 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.

  7. Diagnostic value of renal cortex-to-medulla contrast on magnetic resonance images

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    Terrier, F.; Hricak, H.; Justich, E.; Dooms, G.C.; Grodd, W.

    1986-05-01

    The diagnostic value of magnetic resonance contrast between the renal cortex and renal medulla as an indicator of renal disease was retrospectively studied in 38 patients (ten patients with a variety of diseases affecting the renal parenchyma, nine with renal obstruction, four with diffusely infiltrating renal-cell carcinoma, one with renal hematoma, nine with normally functioning renal allograft, and five with renal allograft failure). Twelve normal volunteers served as controls. On spin-echo (SE) images (TR 0.5 sec, TE 28 msec), the cortex-to-medulla contrast was present in the kidneys of all the normal volunteers (19% contrast +-2% S.D.) and in all the normally functioning allografts (17% contrast +-2% S.D.). Decrease or absence of cortex-to-medulla contrast (SE image with TR 0.5 sec and TE 28 msec) was found to be a sensitive but nonspecific sign of renal disease. It occurred in renal diseases of various causes and was produced by different pathophysiologic mechanisms such as edema, scarring, and tissue replacement by neoplasm or hematoma. Of the calculated T1 and T2 relaxation times and spin density of the cortex and the medulla, the T1 changes most consistently reflected renal disease.

  8. 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.

  9. Neural structures underlying set-shifting: roles of medial prefrontal cortex and anterior cingulate cortex.

    Science.gov (United States)

    Bissonette, Gregory B; Powell, Elizabeth M; Roesch, Matthew R

    2013-08-01

    Impaired attentional set-shifting and inflexible decision-making are problems frequently observed during normal aging and in several psychiatric disorders. To understand the neuropathophysiology of underlying inflexible behavior, animal models of attentional set-shifting have been developed to mimic tasks such as the Wisconsin Card Sorting Task (WCST), which tap into a number of cognitive functions including stimulus-response encoding, working memory, attention, error detection, and conflict resolution. Here, we review many of these tasks in several different species and speculate on how prefrontal cortex and anterior cingulate cortex might contribute to normal performance during set-shifting. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. The development of spatial frequency discrimination.

    Science.gov (United States)

    Patel, Ashna; Maurer, Daphne; Lewis, Terri L

    2010-12-31

    We compared thresholds for discriminating spatial frequency for children aged 5, 7, and 9 years, and adults at two baseline spatial frequencies (1 and 3 cpd). In Experiment 1, the minimum change from baseline necessary to detect a change in spatial frequency from either baseline decreased with age from 34% in 5-year-olds to 11% in 7-year-olds, 8% in 9-year-olds, and 6% in adults. The data were best fit by an exponential function reflecting the rapid improvement in thresholds between 5 and 7 years of age and more gradual improvement thereafter (r(2) = 0.50, p spatial frequencies side by side for an unlimited time. The pattern of development for sensitivity to spatial frequency (this study) resembles those for the development of sensitivity to orientation (T. L. Lewis, S. E. Chong, & D. Maurer, 2009) and contrast (D. Ellemberg, T. L. Lewis, C. H. Lui, & D. Maurer, 1999). The similar patterns are consistent with theories of common underlying mechanisms in primary visual cortex (A. Vincent & D. Regan, 1995; W. Zhu, M. Shelley, & R. Shapley, 2008) and suggest that those mechanisms continue to develop throughout childhood.

  11. The Contribution of Primary Motor Cortex Is Essential for Probabilistic Implicit Sequence Learning: Evidence from Theta Burst Magnetic Stimulation

    Science.gov (United States)

    Wilkinson, Leonora; Teo, James T.; Obeso, Ignacio; Rothwell, John C.; Jahanshahi, Marjan

    2010-01-01

    Theta burst transcranial magnetic stimulation (TBS) is considered to produce plastic changes in human motor cortex. Here, we examined the inhibitory and excitatory effects of TBS on implicit sequence learning using a probabilistic serial reaction time paradigm. We investigated the involvement of several cortical regions associated with implicit…

  12. Layer-specific entrainment of gamma-band neural activity by the alpha rhythm in monkey visual cortex

    NARCIS (Netherlands)

    Spaak, E.; Bonnefond, M.; Maier, A.; Leopold, D.A.; Jensen, O.

    2012-01-01

    Although the mammalian neocortex has a clear laminar organization, layer-specific neuronal computations remain to be uncovered. Several studies suggest that gamma band activity in primary visual cortex (V1) is produced in granular and superficial layers and is associated with the processing of visua

  13. Enhanced representation of spectral contrasts in the primary auditory cortex

    Directory of Open Access Journals (Sweden)

    Nicolas eCatz

    2013-06-01

    Full Text Available The role of early auditory processing may be to extract some elementary features from an acoustic mixture in order to organize the auditory scene. To accomplish this task, the central auditory system may rely on the fact that sensory objects are often composed of spectral edges, i.e. regions where the stimulus energy changes abruptly over frequency. The processing of acoustic stimuli may benefit from a mechanism enhancing the internal representation of spectral edges. While the visual system is thought to rely heavily on this mechanism (enhancing spatial edges, it is still unclear whether a related process plays a significant role in audition. We investigated the cortical representation of spectral edges, using acoustic stimuli composed of multi-tone pips whose time-averaged spectral envelope contained suppressed or enhanced regions. Importantly, the stimuli were designed such that neural responses properties could be assessed as a function of stimulus frequency during stimulus presentation. Our results suggest that the representation of acoustic spectral edges is enhanced in the auditory cortex, and that this enhancement is sensitive to the characteristics of the spectral contrast profile, such as depth, sharpness and width. Spectral edges are maximally enhanced for sharp contrast and large depth. Cortical activity was also suppressed at frequencies within the suppressed region. To note, the suppression of firing was larger at frequencies nearby the lower edge of the suppressed region than at the upper edge. Overall, the present study gives critical insights into the processing of spectral contrasts in the auditory system.

  14. Live imaging of mitosis in the developing mouse embryonic cortex.

    Science.gov (United States)

    Pilaz, Louis-Jan; Silver, Debra L

    2014-06-04

    Although of short duration, mitosis is a complex and dynamic multi-step process fundamental for development of organs including the brain. In the developing cerebral cortex, abnormal mitosis of neural progenitors can cause defects in brain size and function. Hence, there is a critical need for tools to understand the mechanisms of neural progenitor mitosis. Cortical development in rodents is an outstanding model for studying this process. Neural progenitor mitosis is commonly examined in fixed brain sections. This protocol will describe in detail an approach for live imaging of mitosis in ex vivo embryonic brain slices. We will describe the critical steps for this procedure, which include: brain extraction, brain embedding, vibratome sectioning of brain slices, staining and culturing of slices, and time-lapse imaging. We will then demonstrate and describe in detail how to perform post-acquisition analysis of mitosis. We include representative results from this assay using the vital dye Syto11, transgenic mice (histone H2B-EGFP and centrin-EGFP), and in utero electroporation (mCherry-α-tubulin). We will discuss how this procedure can be best optimized and how it can be modified for study of genetic regulation of mitosis. Live imaging of mitosis in brain slices is a flexible approach to assess the impact of age, anatomy, and genetic perturbation in a controlled environment, and to generate a large amount of data with high temporal and spatial resolution. Hence this protocol will complement existing tools for analysis of neural progenitor mitosis.

  15. Transcranial focused ultrasound stimulation of human primary visual cortex

    Science.gov (United States)

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

    2016-09-01

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

  16. The posterior parietal cortex remaps touch into external space.

    Science.gov (United States)

    Azañón, Elena; Longo, Matthew R; Soto-Faraco, Salvador; Haggard, Patrick

    2010-07-27

    Localizing tactile events in external space is required for essential functions such as orienting, haptic exploration, and goal-directed action in peripersonal space. In order to map somatosensory input into a spatiotopic representation, information about skin location must be integrated with proprioceptive information about body posture. We investigated the neural bases of this tactile remapping mechanism in humans by disrupting neural activity in the putative human homolog of the monkey ventral intraparietal area (hVIP), within the right posterior parietal cortex (rPPC), which is thought to house external spatial representations. Participants judged the elevation of touches on their (unseen) forearm relative to touches on their face. Arm posture was passively changed along the vertical axis, so that elevation judgments required the use of an external reference frame. Single-pulse transcranial magnetic stimulation (TMS) over the rPPC significantly impaired performance compared to a control site (vertex). Crucially, proprioceptive judgments of arm elevation or tactile localization on the skin remained unaffected by rPPC TMS. This selective disruption of tactile remapping suggests a distinct computational process dissociable from pure proprioceptive and somatosensory localization. Furthermore, this finding highlights the causal role of human PPC, putatively VIP, in remapping touch into external space.

  17. Information processing occurs via critical avalanches in a model of the primary visual cortex

    Science.gov (United States)

    Bortolotto, G. S.; Girardi-Schappo, M.; Gonsalves, J. J.; Pinto, L. T.; Tragtenberg, M. H. R.

    2016-01-01

    We study a new biologically motivated model for the Macaque monkey primary visual cortex which presents power-law avalanches after a visual stimulus. The signal propagates through all the layers of the model via avalanches that depend on network structure and synaptic parameter. We identify four different avalanche profiles as a function of the excitatory postsynaptic potential. The avalanches follow a size-duration scaling relation and present critical exponents that match experiments. The structure of the network gives rise to a regime of two characteristic spatial scales, one of which vanishes in the thermodynamic limit.

  18. Orbitofrontal cortex function and structure in depression.

    Science.gov (United States)

    Drevets, Wayne C

    2007-12-01

    The orbitofrontal cortex (OFC) has been implicated in the pathophysiology of major depression by evidence obtained using neuroimaging, neuropathologic, and lesion analysis techniques. The abnormalities revealed by these techniques show a regional specificity, and suggest that some OFC regions which appear cytoarchitectonically distinct also are functionally distinct with respect to mood regulation. For example, the severity of depression correlates inversely with physiological activity in parts of the posterior lateral and medial OFC, consistent with evidence that dysfunction of the OFC associated with cerebrovascular lesions increases the vulnerability for developing the major depressive syndrome. The posterior lateral and medial OFC function may also be impaired in individuals who develop primary mood disorders, as these patients show grey-matter volumetric reductions, histopathologic abnormalities, and altered hemodynamic responses to emotionally valenced stimuli, probabilistic reversal learning, and reward processing. In contrast, physiological activity in the anteromedial OFC situated in the ventromedial frontal polar cortex increases during the depressed versus the remitted phases of major depressive disorder to an extent that is positively correlated with the severity of depression. Effective antidepressant treatment is associated with a reduction in activity in this region. Taken together these data are compatible with evidence from studies in experimental animals indicating that some orbitofrontal and medial prefrontal cortex regions function to inhibit, while others function to enhance, emotional expression. Alterations in the functional balance between these regions and the circuits they form with anatomically related areas of the temporal lobe, striatum, thalamus, and brain stem thus may underlie the pathophysiology of mood disorders, such as major depression.

  19. Inhibition by somatostatin interneurons in olfactory cortex

    Directory of Open Access Journals (Sweden)

    Adam M Large

    2016-08-01

    Full Text Available Inhibitory circuitry plays an integral cortical network activity. The development of transgenic mouse lines targeting unique interneuron classes has significantly advanced our understanding of the functional roles of specific inhibitory circuits in neocortical sensory processing. In contrast, considerably less is known about the circuitry and function of interneuron classes in piriform cortex, a paleocortex responsible for olfactory processing. In this study, we sought to utilize transgenic technology to investigate inhibition mediated by somatostatin (SST interneurons onto pyramidal cells, parvalbumin (PV interneurons and other interneuron classes. As a first step, we characterized the anatomical distributions and intrinsic properties of SST and PV interneurons in four transgenic lines (SST-cre, GIN, PV-cre and G42 that are commonly interbred to investigate inhibitory connectivity. Surprisingly, the distributions SST and PV cell subtypes targeted in the GIN and G42 lines were sparse in piriform cortex compared to neocortex. Moreover, two-thirds of interneurons recorded in the SST-cre line had electrophysiological properties similar to fast spiking (FS interneurons rather than regular (RS or low threshold spiking (LTS phenotypes. Nonetheless, like neocortex, we find that SST-cells broadly inhibit a number of unidentified interneuron classes including putatively identified PV cells and surprisingly, other SST cells. We also confirm that SST-cells inhibit pyramidal cell dendrites and thus, influence dendritic integration of afferent and recurrent inputs to the piriform cortex. Altogether, our findings suggest that somatostatin interneurons play an important role in regulating both excitation and the global inhibitory network during olfactory processing.

  20. Apraxia, pantomime and the parietal cortex.

    Science.gov (United States)

    Niessen, E; Fink, G R; Weiss, P H

    2014-01-01

    Apraxia, a disorder of higher motor cognition, is a frequent and outcome-relevant sequel of left hemispheric stroke. Deficient pantomiming of object use constitutes a key symptom of apraxia and is assessed when testing for apraxia. To date the neural basis of pantomime remains controversial. We here review the literature and perform a meta-analysis of the relevant structural and functional imaging (fMRI/PET) studies. Based on a systematic literature search, 10 structural and 12 functional imaging studies were selected. Structural lesion studies associated pantomiming deficits with left frontal, parietal and temporal lesions. In contrast, functional imaging studies associate pantomimes with left parietal activations, with or without concurrent frontal or temporal activations. Functional imaging studies that selectively activated parietal cortex adopted the most stringent controls. In contrast to previous suggestions, current analyses show that both lesion and functional studies support the notion of a left-hemispheric fronto-(temporal)-parietal network underlying pantomiming object use. Furthermore, our review demonstrates that the left parietal cortex plays a key role in pantomime-related processes. More specifically, stringently controlled fMRI-studies suggest that in addition to storing motor schemas, left parietal cortex is also involved in activating these motor schemas in the context of pantomiming object use. In addition to inherent differences between structural and functional imaging studies and consistent with the dedifferentiation hypothesis, the age difference between young healthy subjects (typically included in functional imaging studies) and elderly neurological patients (typically included in structural lesion studies) may well contribute to the finding of a more distributed representation of pantomiming within the motor-dominant left hemisphere in the elderly.

  1. Determining Physical Properties of the Cell Cortex

    Science.gov (United States)

    Saha, Arnab; Nishikawa, Masatoshi; Behrndt, Martin; Heisenberg, Carl-Philipp; Jülicher, Frank; Grill, Stephan W.

    2016-03-01

    Actin and myosin assemble into a thin layer of a highly dynamic network underneath the membrane of eukaryotic cells. This network generates the forces that drive cell and tissue-scale morphogenetic processes. The effective material properties of this active network determine large-scale deformations and other morphogenetic events. For example,the characteristic time of stress relaxation (the Maxwell time)in the actomyosin sets the time scale of large-scale deformation of the cortex. Similarly, the characteristic length of stress propagation (the hydrodynamic length) sets the length scale of slow deformations, and a large hydrodynamic length is a prerequisite for long-ranged cortical flows. Here we introduce a method to determine physical parameters of the actomyosin cortical layer (in vivo). For this we investigate the relaxation dynamics of the cortex in response to laser ablation in the one-cell-stage {\\it C. elegans} embryo and in the gastrulating zebrafish embryo. These responses can be interpreted using a coarse grained physical description of the cortex in terms of a two dimensional thin film of an active viscoelastic gel. To determine the Maxwell time, the hydrodynamic length and the ratio of active stress and per-area friction, we evaluated the response to laser ablation in two different ways: by quantifying flow and density fields as a function of space and time, and by determining the time evolution of the shape of the ablated region. Importantly, both methods provide best fit physical parameters that are in close agreement with each other and that are similar to previous estimates in the two systems. We provide an accurate and robust means for measuring physical parameters of the actomyosin cortical layer.It can be useful for investigations of actomyosin mechanics at the cellular-scale, but also for providing insights in the active mechanics processes that govern tissue-scale morphogenesis.

  2. Behavioural and neural interaction between spatial inhibition of return and the Simon effect

    Directory of Open Access Journals (Sweden)

    Pengfei eWang

    2013-09-01

    Full Text Available It has been well documented that the anatomically independent attention networks in the human brain interact functionally to achieve goal-directed behaviours. By combining spatial inhibition of return (IOR which implicates the orienting network with some executive function tasks (e.g., the Stroop and the flanker effects which implicate the executive network, researchers consistently found that the interference effects are significantly reduced at cued compared to uncued locations, indicating the functional interaction between the two attention networks. However, a unique, but consistent, effect is observed when spatial IOR is combined with the Simon effect: the Simon effect is significantly higher at the cued than uncued locations. To investigate the neural substrates underlying this phenomenon, we orthogonally combined the spatial IOR with the Simon effect in the present event-related fMRI study. Our behavioural data replicated previous results by showing larger Simon effect at the cued location. At the neural level, we found shared spatial representation system between spatial IOR and the Simon effect in bilateral posterior parietal cortex; spatial IOR specifically activated bilateral superior parietal cortex while the Simon effect specifically activated bilateral middle frontal cortex. Moreover, left precentral gyrus was involved in the neural interaction between spatial IOR and the Simon effect by showing significantly higher neural activity in the ‘Cued_Congruent’ condition. Taken together, our results suggest that due to the shared spatial representation system in the posterior parietal cortex, responses were significantly facilitated when spatial IOR and the Simon effect relied on the same spatial representations, i.e., in the ‘Cued_Congruent’ condition. Correspondingly, the sensorimotor system was significantly involved in the ‘Cued_Congruent’ condition to fasten the responses, which indirectly resulted in the enhanced Simon

  3. 东北粮食主产区农业生态系统健康格局与因子诊断——以吉林省为例%Spatial-temporal pattern and factor diagnoses of agroecosystem health in major grain producing areas of Northeast China: A case study in Jilin Province

    Institute of Scientific and Technical Information of China (English)

    赵宏波; 郑辉; 苗长虹; 邵田田; 冯渊博

    2016-01-01

    It is of great significance to study agroecosystem health in major grain producing areas based on the theory and method of ecosystem health.This paper selected Jilin Province as the study area,and an evaluation index system of agroecosystem health was built based on the SSI-VOR conceptual framework model.Using the optimal combined weights method,comprehensive evaluation assessment,GIS spatial analysis and grey slope similarity incidence models,the spatial-temporal pattern of agroecosystem health and influence factors were analyzed from 2000 to 2011 in Jilin Province.The results indicated that,temporally,the composite index of agroecosystem health showed a rising trend in Jilin Province from 1995 to 2011,and the agroecosystem health level changed from not healthy to relatively healthy;spatially,the spatial discrepancy of agroecosystem health level tended to become larger,which remained unchanged in central area,while was gradually improved in southeast and west.The main contributors which improved the agroecosystem health level were economic driving force,environmental management and social development,while the main ‘dragging’ factors were ecological pressure,organization structure and input capacity.Finally,relevant measures were put forward to improve the agroecosystem health condition.%运用生态系统健康的理论与方法研究粮食主产区农业生态系统健康问题具有重要的意义,以东北粮食主产区的典型区域吉林省为研究对象,基于构建的胁迫-状态-免疫(S-S-I)与活力-结构组织-恢复力(V-O-R)农业生态系统健康评价指标体系,运用最优组合赋权法、综合评价模型、GIS空间分析技术和灰色斜率相似关联度诊断模型对2000-2011年吉林省农业生态系统健康的时空格局以及影响因子进行分析.结果表明:时间特征上,2000-2011年吉林省农业生态健康等级从“不健康级”状态向“较健康级”状态转变,农业生态系统健康水平

  4. Texture coarseness responsive neurons and their mapping in layer 2–3 of the rat barrel cortex in vivo

    Science.gov (United States)

    Garion, Liora; Dubin, Uri; Rubin, Yoav; Khateb, Mohamed; Schiller, Yitzhak; Azouz, Rony; Schiller, Jackie

    2014-01-01

    Texture discrimination is a fundamental function of somatosensory systems, yet the manner by which texture is coded and spatially represented in the barrel cortex are largely unknown. Using in vivo two-photon calcium imaging in the rat barrel cortex during artificial whisking against different surface coarseness or controlled passive whisker vibrations simulating different coarseness, we show that layer 2–3 neurons within barrel boundaries differentially respond to specific texture coarsenesses, while only a minority of neurons responded monotonically with increased or decreased surface coarseness. Neurons with similar preferred texture coarseness were spatially clustered. Multi-contact single unit recordings showed a vertical columnar organization of texture coarseness preference in layer 2–3. These findings indicate that layer 2–3 neurons perform high hierarchical processing of tactile information, with surface coarseness embodied by distinct neuronal subpopulations that are spatially mapped onto the barrel cortex. DOI: http://dx.doi.org/10.7554/eLife.03405.001 PMID:25233151

  5. Aberrant functional connectivity differentiates retrosplenial cortex from posterior cingulate cortex in prodromal Alzheimer's disease.

    Science.gov (United States)

    Dillen, Kim N H; Jacobs, Heidi I L; Kukolja, Juraj; von Reutern, Boris; Richter, Nils; Onur, Özgür A; Dronse, Julian; Langen, Karl-Josef; Fink, Gereon R

    2016-08-01

    The posterior cingulate cortex (PCC) is a key hub of the default mode network, a resting-state network involved in episodic memory, showing functional connectivity (FC) changes in Alzheimer's disease (AD). However, PCC is a cytoarchitectonically heterogeneous region. Specifically, the retrosplenial cortex (RSC), often subsumed under the PCC, is an area functionally and microanatomically distinct from PCC. To investigate FC patterns of RSC and PCC separately, we used resting-state functional magnetic resonance imaging in healthy aging participants, patients with subjective cognitive impairment, and prodromal AD. Compared to the other 2 groups, we found higher FC from RSC to frontal cortex in subjective cognitive impairment but higher FC to occipital cortex in prodromal AD. Conversely, FC from PCC to the lingual gyrus was higher in prodromal AD. Furthermore, data indicate that RSC and PCC are characterized by differential FC patterns represented by hub-specific interactions with memory and attentions scores in prodromal AD compared to cognitively normal individuals, possibly reflecting compensatory mechanisms for RSC and neurodegenerative processes for PCC. Data thus confirm and extend previous studies suggesting that the RSC is functionally distinct from PCC.

  6. Spatial econometrics using microdata

    CERN Document Server

    Dubé, Jean

    2014-01-01

    This book provides an introduction to spatial analyses concerning disaggregated (or micro) spatial data.Particular emphasis is put on spatial data compilation and the structuring of the connections between the observations. Descriptive analysis methods of spatial data are presented in order to identify and measure the spatial, global and local dependency.The authors then focus on autoregressive spatial models, to control the problem of spatial dependency between the residues of a basic linear statistical model, thereby contravening one of the basic hypotheses of the ordinary least squares appr

  7. The encoding of auditory objects in auditory cortex: insights from magnetoencephalography.

    Science.gov (United States)

    Simon, Jonathan Z

    2015-02-01

    Auditory objects, like their visual counterparts, are perceptually defined constructs, but nevertheless must arise from underlying neural circuitry. Using magnetoencephalography (MEG) recordings of the neural responses of human subjects listening to complex auditory scenes, we review studies that demonstrate that auditory objects are indeed neurally represented in auditory cortex. The studies use neural responses obtained from different experiments in which subjects selectively listen to one of two competing auditory streams embedded in a variety of auditory scenes. The auditory streams overlap spatially and often spectrally. In particular, the studies demonstrate that selective attentional gain does not act globally on the entire auditory scene, but rather acts differentially on the separate auditory streams. This stream-based attentional gain is then used as a tool to individually analyze the different neural representations of the competing auditory streams. The neural representation of the attended stream, located in posterior auditory cortex, dominates the neural responses. Critically, when the intensities of the attended and background streams are separately varied over a wide intensity range, the neural representation of the attended speech adapts only to the intensity of that speaker, irrespective of the intensity of the background speaker. This demonstrates object-level intensity gain control in addition to the above object-level selective attentional gain. Overall, these results indicate that concurrently streaming auditory objects, even if spectrally overlapping and not resolvable at the auditory periphery, are individually neurally encoded in auditory cortex, as separate objects. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Analogues of simple and complex cells in rhesus monkey auditory cortex.

    Science.gov (United States)

    Tian, Biao; Kuśmierek, Paweł; Rauschecker, Josef P

    2013-05-01

    Receptive fields (RFs) of neurons in primary visual cortex have traditionally been subdivided into two major classes: "simple" and "complex" cells. Simple cells were originally defined by the existence of segregated subregions within their RF that respond to either the on- or offset of a light bar and by spatial summation within each of these regions, whereas complex cells had ON and OFF regions that were coextensive in space [Hubel DH, et al. (1962) J Physiol 160:106-154]. Although other definitions based on the linearity of response modulation have been proposed later [Movshon JA, et al. (1978) J Physiol 283:53-77; Skottun BC, et al. (1991) Vision Res 31(7-8):1079-1086], the segregation of ON and OFF subregions has remained an important criterion for the distinction between simple and complex cells. Here we report that response profiles of neurons in primary auditory cortex of monkeys show a similar distinction: one group of cells has segregated ON and OFF subregions in frequency space; and another group shows ON and OFF responses within largely overlapping response profiles. This observation is intriguing for two reasons: (i) spectrotemporal dissociation in the auditory domain provides a basic neural mechanism for the segregation of sounds, a fundamental prerequisite for auditory figure-ground discrimination; and (ii) the existence of similar types of RF organization in visual and auditory cortex would support the existence of a common canonical processing algorithm within cortical columns.

  9. Top-Down-Mediated Facilitation in the Visual Cortex Is Gated by Subcortical Neuromodulation.

    Science.gov (United States)

    Pafundo, Diego E; Nicholas, Mark A; Zhang, Ruilin; Kuhlman, Sandra J

    2016-03-09

    Response properties in primary sensory cortices are highly dependent on behavioral state. For example, the nucleus basalis of the forebrain plays a critical role in enhancing response properties of excitatory neurons in primary visual cortex (V1) during active exploration and learning. Given the strong reciprocal connections between hierarchically arranged cortical regions, how are increases in sensory response gain constrained to prevent runaway excitation? To explore this, we used in vivo two-photon guided cell-attached recording in conjunction with spatially restricted optogenetic photo-inhibition of higher-order visual cortex in mice. We found that the principle feedback projection to V1 originating from the lateral medial area (LM) facilitated visual responses in layer 2/3 excitatory neurons by ∼20%. This facilitation was reduced by half during basal forebrain activation due to differential response properties between LM and V1. Our results demonstrate that basal-forebrain-mediated increases in response gain are localized to V1 and are not propagated to LM and establish that subcortical modulation of visual cortex is regionally distinct.

  10. Simultaneous high-definition transcranial direct current stimulation of the motor cortex and motor imagery.

    Science.gov (United States)

    Baxter, Bryan S; Edelman, Bradley; Zhang, Xiaotong; Roy, Abhrajeet; He, Bin

    2014-01-01

    Transcranial direct current stimulation (tDCS) has been used to affect the excitability of neurons within the cerebral cortex. Improvements in motor learning have been found in multiple studies when tDCS was applied to the motor cortex during or before task learning is performed. The application of tDCS to motor imagery, a cognitive task showing activation in similar areas to motor execution, has resulted in differing effects based on the amplitude and duration of stimulation. We utilize high definition tDCS, a more spatially localized version of tDCS, to investigate the effect of anodal stimulation on human motor imagery performance. In parallel, we model this stimulation using a finite element model to calculate stimulation area and electrical field amplitude within the brain in the motor cortex and non-stimulated frontal and parietal regions. Overall, we found a delayed increase in resting baseline power 30 minutes post stimulation in both the right and left sensorimotor cortices which resulted in an increase in event-related desynchronization.

  11. Representation of dynamic interaural phase difference in auditory cortex of awake rhesus macaques.

    Science.gov (United States)

    Scott, Brian H; Malone, Brian J; Semple, Malcolm N

    2009-04-01

    Neurons in auditory cortex of awake primates are selective for the spatial location of a sound source, yet the neural representation of the binaural cues that underlie this tuning remains undefined. We examined this representation in 283 single neurons across the low-frequency auditory core in alert macaques, trained to discriminate binaural cues for sound azimuth. In response to binaural beat stimuli, which mimic acoustic motion by modulating the relative phase of a tone at the two ears, these neurons robustly modulate their discharge rate in response to this directional cue. In accordance with prior studies, the preferred interaural phase difference (IPD) of these neurons typically corresponds to azimuthal locations contralateral to the recorded hemisphere. Whereas binaural beats evoke only transient discharges in anesthetized cortex, neurons in awake cortex respond throughout the IPD cycle. In this regard, responses are consistent with observations at earlier stations of the auditory pathway. Discharge rate is a band-pass function of the frequency of IPD modulation in most neurons (73%), but both discharge rate and temporal synchrony are independent of the direction of phase modulation. When subjected to a receiver operator characteristic analysis, the responses of individual neurons are insufficient to account for the perceptual acuity of these macaques in an IPD discrimination task, suggesting the need for neural pooling at the cortical level.

  12. Spatial Relation Resolution and Spatial Relation Abstraction

    Institute of Scientific and Technical Information of China (English)

    AI Tinghua; LIU Yaolin

    2003-01-01

    This paper attempts toregard spatial relation transformationas an important process in map gener-alization. The spatial relation generali-zation can be divided into the compo-nents of abstraction: topology, dis-tance and orientation. The concept‘ spatial relation resolution' is intro-duced to describe the constraints ofrelative spatial relation. On the basisof nine intersection models, the cardi-nal direction models and the iso-dis-tance-relation models, this paper givesthree sorts of relation resolution repre-sentations for topological, distance andorientation relation, respectively. Twomapping implementations in map gen-eralization is discussed.

  13. Neurons and circuits for odor processing in the piriform cortex.

    Science.gov (United States)

    Bekkers, John M; Suzuki, Norimitsu

    2013-07-01

    Increased understanding of the early stages of olfaction has lead to a renewed interest in the higher brain regions responsible for forming unified 'odor images' from the chemical components detected by the nose. The piriform cortex, which is one of the first cortical destinations of olfactory information in mammals, is a primitive paleocortex that is critical for the synthetic perception of odors. Here we review recent work that examines the cellular neurophysiology of the piriform cortex. Exciting new findings have revealed how the neurons and circuits of the piriform cortex process odor information, demonstrating that, despite its superficial simplicity, the piriform cortex is a remarkably subtle and intricate neural circuit.

  14. Iso-orientation domains in cat visual cortex are arranged in pinwheel-like patterns

    Science.gov (United States)

    Bonhoeffer, Tobias; Grinvald, Amiram

    1991-10-01

    THE mammalian cortex is organized in a columnar fashion: neurons lying below each other from the pia to the white matter usually share many functional properties. Across the cortical surface, cells with similar response properties are also clustered together, forming elongated bands or patches. Some response properties, such as orientation preference in the visual cortex, change gradually across the cortical surface forming 'orientation maps'. To determine the precise layout of iso-orientation domains, knowledge of responses not only to one but to many stimulus orientations is essential. Therefore, the exact depiction of orientation maps has been hampered by technical difficulties and remained controversial for almost thirty years. Here we use in vivo optical imaging based on intrinsic signals to gather information on the responses of a piece of cortex to gratings in many different orientations. This complete set of responses then provides detailed information on the structure of the orientation map in a large patch of cortex from area 18 of the cat. We find that cortical regions that respond best to one orientation form highly ordered patches rather than elongated bands. These iso-orientation patches are organized around 'orientation centres', producing pinwheel-like patterns in which the orientation preference of cells is changing continuously across the cortex. We have also analysed our data for fast changes in orientation preference and find that these 'fractures' are limited to the orientation centres. The pinwheels and orientation centres are such a prominent organizational feature that it should be important to understand their development as well as their function in the processing of visual information.

  15. Cerebral cortex hyperthyroidism of newborn mct8-deficient mice transiently suppressed by lat2 inactivation.

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    Bárbara Núñez

    Full Text Available Thyroid hormone entry into cells is facilitated by transmembrane transporters. Mutations of the specific thyroid hormone transporter, MCT8 (Monocarboxylate Transporter 8, SLC16A2 cause an X-linked syndrome of profound neurological impairment and altered thyroid function known as the Allan-Herndon-Dudley syndrome. MCT8 deficiency presumably results in failure of thyroid hormone to reach the neural target cells in adequate amounts to sustain normal brain development. However during the perinatal period the absence of Mct8 in mice induces a state of cerebral cortex hyperthyroidism, indicating increased brain access and/or retention of thyroid hormone. The contribution of other transporters to thyroid hormone metabolism and action, especially in the context of MCT8 deficiency is not clear. We have analyzed the role of the heterodimeric aminoacid transporter Lat2 (Slc7a8, in the presence or absence of Mct8, on thyroid hormone concentrations and on expression of thyroid hormone-dependent cerebral cortex genes. To this end we generated Lat2-/-, and Mct8-/yLat2-/- mice, to compare with wild type and Mct8-/y mice during postnatal development. As described previously the single Mct8 KO neonates had a transient increase of 3,5,3'-triiodothyronine concentration and expression of thyroid hormone target genes in the cerebral cortex. Strikingly the absence of Lat2 in the double Mct8Lat2 KO prevented the effect of Mct8 inactivation in newborns. The Lat2 effect was not observed from postnatal day 5 onwards. On postnatal day 21 the Mct8 KO displayed the typical pattern of thyroid hormone concentrations in plasma, decreased cortex 3,5,3'-triiodothyronine concentration and Hr expression, and concomitant Lat2 inactivation produced little to no modifications. As Lat2 is expressed in neurons and in the choroid plexus, the results support a role for Lat2 in the supply of thyroid hormone to the cerebral cortex during early postnatal development.

  16. Effect of prenatal exposure to ethanol on the development of cerebral cortex: I. Neuronal generation

    Energy Technology Data Exchange (ETDEWEB)

    Miller, M.W.

    1988-06-01

    Prenatal exposure to ethanol causes profound disruptions in the development of the cerebral cortex. Therefore, the effect of in utero ethanol exposure on the generation of neurons was determined. Pregnant rats were fed a liquid diet in which ethanol constituted 37.5% of the total caloric content (Et) or pair-fed an isocaloric control diet (Ct) from gestational day (GD) 6 to the day of birth. The time of origin of cortical neurons was determined in the mature pups of females injected with (3H)thymidine on one day during the period from GD 10 to the day of birth. The brains were processed by standard autoradiographic techniques. Ethanol exposure produced multiple defects in neuronal ontogeny. The period of generation was 1-2 days later for Et-treated rats than for rats exposed prenatally to either control diet. Moreover, the generation period was 1-2 days longer in Et-treated rats. The numbers of neurons generated on a specific day was altered; from GD 12-19 significantly fewer neurons were generated in Et-treated rats than in Ct-treated rats, whereas after GD 19 more neurons were born. The distribution of neurons generated on a specific day was disrupted; most notable was the distribution of late-generated neurons in deep cortex of Et-treated rats rather than in superficial cortex as they are in controls. Cortical neurons in Et-treated rats tended to be smaller than in Ct-treated rats, particularly early generated neurons in deep cortex. The late-generated neurons in Et-treated rats were of similar size to those in Ct-treated rats despite their abnormal position in deep cortex. Neurons in Ct-treated rats tended to be rounder than those in Et-treated rats which were more polarized in the radial orientation.

  17. The role of hearing ability and speech distortion in the facilitation of articulatory motor cortex.

    Science.gov (United States)

    Nuttall, Helen E; Kennedy-Higgins, Daniel; Devlin, Joseph T; Adank, Patti

    2017-01-08

    Excitability of articulatory motor cortex is facilitated when listening to speech in challenging conditions. Beyond this, however, we have little knowledge of what listener-specific and speech-specific factors engage articulatory facilitation during speech perception. For example, it is unknown whether speech motor activity is independent or dependent on the form of distortion in the speech signal. It is also unknown if speech motor facilitation is moderated by hearing ability. We investigated these questions in two experiments. We applied transcranial magnetic stimulation (TMS) to the lip area of primary motor cortex (M1) in young, normally hearing participants to test if lip M1 is sensitive to the quality (Experiment 1) or quantity (Experiment 2) of distortion in the speech signal, and if lip M1 facilitation relates to the hearing ability of the listener. Experiment 1 found that lip motor evoked potentials (MEPs) were larger during perception of motor-distorted speech that had been produced using a tongue depressor, and during perception of speech presented in background noise, relative to natural speech in quiet. Experiment 2 did not find evidence of motor system facilitation when speech was presented in noise at signal-to-noise ratios where speech intelligibility was at 50% or 75%, which were significantly less severe noise levels than used in Experiment 1. However, there was a significant interaction between noise condition and hearing ability, which indicated that when speech stimuli were correctly classified at 50%, speech motor facilitation was observed in individuals with better hearing, whereas individuals with relatively worse but still normal hearing showed more activation during perception of clear speech. These findings indicate that the motor system may be sensitive to the quantity, but not quality, of degradation in the speech signal. Data support the notion that motor cortex complements auditory cortex during speech perception, and point to a role

  18. Integrated spatial sampling modeling of geospatial data

    Institute of Scientific and Technical Information of China (English)

    LI Lianfa; WANG Jinfeng

    2004-01-01

    Spatial sampling is a necessary and important method for extracting geospatial data and its methodology directly affects the geo-analysis results. Counter to the deficiency of separate models of spatial sampling, this article analyzes three crucial elements of spatial sampling (frame, correlation and decision diagram) and induces its general integrated model. The program of Spatial Sampling Integration (SSI) has been developed with Component Object Model (COM) to realize the general integrated model. In two practical applications, i.e. design of the monitoring network of natural disasters and sampling survey of the areas of non-cultivated land, SSI has produced accurate results at less cost, better realizing the cost-effective goal of sampling toward the geo-objects with spatial correlation. The two cases exemplify expanded application and convenient implementation of the general integrated model with inset components in an integrated environment, which can also be extended to other modeling of spatial analysis.

  19. Fundamentals of spatial data quality

    CERN Document Server

    Devillers, Rodolphe

    2010-01-01

    This book explains the concept of spatial data quality, a key theory for minimizing the risks of data misuse in a specific decision-making context. Drawing together chapters written by authors who are specialists in their particular field, it provides both the data producer and the data user perspectives on how to evaluate the quality of vector or raster data which are both produced and used. It also covers the key concepts in this field, such as: how to describe the quality of vector or raster data; how to enhance this quality; how to evaluate and document it, using methods such as metadata;

  20. Finger somatotopy in human motor cortex.

    Science.gov (United States)

    Beisteiner, R; Windischberger, C; Lanzenberger, R; Edward, V; Cunnington, R; Erdler, M; Gartus, A; Streibl, B; Moser, E; Deecke, L

    2001-06-01

    Although qualitative reports about somatotopic representation of fingers in the human motor cortex exist, up to now no study could provide clear statistical evidence. The goal of the present study was to reinvestigate finger motor somatotopy by means of a thorough investigation of standardized movements of the index and little finger of the right hand. Using high resolution fMRI at 3 Tesla, blood oxygenation level-dependent (BOLD) responses in a group of 26 subjects were repeatedly measured to achieve reliable statistical results. The center of mass of all activated voxels within the primary motor cortex was calculated for each finger and each run. Results of all runs were averaged to yield an individual index and little finger representation for each subject. The mean center of mass localizations for all subjects were then submitted to a paired t test. Results show a highly significant though small scale somatotopy of fingerspecific activation patterns in the order indicated by Penfields motor homunculus. In addition, considerable overlap of finger specific BOLD responses was found. Comparing various methods of analysis, the mean center of mass distance for the two fingers was 2--3 mm with overlapping voxels included and 4--5 mm with overlapping voxels excluded. Our data may be best understood in the context of the work of Schieber (1999) who recently described overlapping somatotopic gradients in lesion studies with humans. Copyright 2001 Academic Press.

  1. Cognitive Control Signals in Posterior Cingulate Cortex

    Directory of Open Access Journals (Sweden)

    Benjamin eHayden

    2010-12-01

    Full Text Available Efficiently shifting between tasks is a central function of cognitive control. The role of the default network—a constellation of areas with high baseline activity that declines during task performance—in cognitive control remains poorly understood. We hypothesized that task switching demands cognitive control to shift the balance of processing towards the external world, and therefore predicted that switching between the two tasks would require suppression of activity of neurons within the CGp. To test this idea, we recorded the activity of single neurons in posterior cingulate cortex (CGp, a central node in the default network, in monkeys performing two interleaved tasks. As predicted, we found that basal levels of neuronal activity were reduced following a switch from one task to another and gradually returned to pre-switch baseline on subsequent trials. We failed to observe these effects in lateral intraparietal cortex (LIP, part of the dorsal fronto-parietal cortical attention network directly connected to CGp. These findings indicate that suppression of neuronal activity in CGp facilitates cognitive control, and suggest that activity in the default network reflects processes that directly compete with control processes elsewhere in the brain..

  2. Motor cortex stimulation in Parkinson's disease.

    Science.gov (United States)

    De Rose, Marisa; Guzzi, Giusy; Bosco, Domenico; Romano, Mary; Lavano, Serena Marianna; Plastino, Massimiliano; Volpentesta, Giorgio; Marotta, Rosa; Lavano, Angelo

    2012-01-01

    Motor Cortex Stimulation (MCS) is less efficacious than Deep Brain Stimulation (DBS) in Parkinson's disease. However, it might be proposed to patients excluded from DBS or unresponsive to DBS. Ten patients with advanced PD underwent unilateral MCS contralaterally to the worst clinical side. A plate electrode was positioned over the motor cortex in the epidural space through single burr hole after identification of the area with neuronavigation and neurophysiological tests. Clinical assessment was performed by total UPDRS, UPDRS III total, UPDRS III-items 27-31, UPDRS IV, and UPDRS II before implantation in off-medication and on-medication states and after surgery at 1, 3, 6, 12, 18, 24, and 36 months in on-medication/on-stimulation and off-medication/on-stimulation states. We assessed changes of quality of life, throughout the Parkinson's disease quality of life scale (PDQoL-39), and the dose of anti-Parkinson's disease medications, throughout the Ldopa equivalent daily dose (LEDD). During off-medication state, we observed moderate and transitory reduction of total UPDRS and UPDRS total scores and significant and long-lasting improvement in UPDRS III items 27-31 score for axial symptoms. There was marked reduction of UPDRS IV score and LEDD. PDQL-39 improvement was also significant. No important complications and adverse events occurred.

  3. Motor Cortex Stimulation in Parkinson's Disease

    Directory of Open Access Journals (Sweden)

    Marisa De Rose

    2012-01-01

    Full Text Available Motor Cortex Stimulation (MCS is less efficacious than Deep Brain Stimulation (DBS in Parkinson's disease. However, it might be proposed to patients excluded from DBS or unresponsive to DBS. Ten patients with advanced PD underwent unilateral MCS contralaterally to the worst clinical side. A plate electrode was positioned over the motor cortex in the epidural space through single burr hole after identification of the area with neuronavigation and neurophysiological tests. Clinical assessment was performed by total UPDRS, UPDRS III total, UPDRS III-items 27–31, UPDRS IV, and UPDRS II before implantation in off-medication and on-medication states and after surgery at 1, 3, 6, 12, 18, 24, and 36 months in on-medication/on-stimulation and off-medication/on-stimulation states. We assessed changes of quality of life, throughout the Parkinson's disease quality of life scale (PDQoL-39, and the dose of anti-Parkinson's disease medications, throughout the Ldopa equivalent daily dose (LEDD. During off-medication state, we observed moderate and transitory reduction of total UPDRS and UPDRS total scores and significant and long-lasting improvement in UPDRS III items 27–31 score for axial symptoms. There was marked reduction of UPDRS IV score and LEDD. PDQL-39 improvement was also significant. No important complications and adverse events occurred.

  4. Real-world scene representations in high-level visual cortex: it's the spaces more than the places.

    Science.gov (United States)

    Kravitz, Dwight J; Peng, Cynthia S; Baker, Chris I

    2011-05-18

    Real-world scenes are incredibly complex and heterogeneous, yet we are able to identify and categorize them effortlessly. In humans, the ventral temporal parahippocampal place area (PPA) has been implicated in scene processing, but scene information is contained in many visual areas, leaving their specific contributions unclear. Although early theories of PPA emphasized its role in spatial processing, more recent reports of its function have emphasized semantic or contextual processing. Here, using functional imaging, we reconstructed the organization of scene representations across human ventral visual cortex by analyzing the distributed response to 96 diverse real-world scenes. We found that, although individual scenes could be decoded in both PPA and early visual cortex (EVC), the structure of representations in these regions was vastly different. In both regions, spatial rather than semantic factors defined the structure of representations. However, in PPA, representations were defined primarily by the spatial factor of expanse (open, closed) and in EVC primarily by distance (near, far). Furthermore, independent behavioral ratings of expanse and distance correlated strongly with representations in PPA and peripheral EVC, respectively. In neither region was content (manmade, natural) a major contributor to the overall organization. Furthermore, the response of PPA could not be used to decode the high-level semantic category of scenes even when spatial factors were held constant, nor could category be decoded across different distances. These findings demonstrate, contrary to recent reports, that the response PPA primarily reflects spatial, not categorical or contextual, aspects of real-world scenes.

  5. Anterior hippocampus and goal-directed spatial decision making.

    Science.gov (United States)

    Viard, Armelle; Doeller, Christian F; Hartley, Tom; Bird, Chris M; Burgess, Neil

    2011-03-23

    Planning spatial paths through our environment is an important part of everyday life and is supported by a neural system including the hippocampus and prefrontal cortex. Here we investigated the precise functional roles of the components of this system in humans by using fMRI as participants performed a simple goal-directed route-planning task. Participants had to choose the shorter of two routes to a goal in a visual scene that might contain a barrier blocking the most direct route, requiring a detour, or might be obscured by a curtain, requiring memory for the scene. The participant's start position was varied to parametrically manipulate their proximity to the goal and the difference in length of the two routes. Activity in medial prefrontal cortex, precuneus, and left posterior parietal cortex was associated with detour planning, regardless of difficulty, whereas activity in parahippocampal gyrus was associated with remembering the spatial layout of the visual scene. Activity in bilateral anterior hippocampal formation showed a strong increase the closer the start position was to the goal, together with medial prefrontal, medial and posterior parietal cortices. Our results are consistent with computational models in which goal proximity is used to guide subsequent navigation and with the association of anterior hippocampal areas with nonspatial functions such as arousal and reward expectancy. They illustrate how spatial and nonspatial functions combine within the anterior hippocampus, and how these functions interact with parahippocampal, parietal, and prefrontal areas in decision making and mnemonic function.

  6. Mouse embryos and chimera cloned from neural cells in the postnatal cerebral cortex.

    Science.gov (United States)

    Makino, Hatsune; Yamazaki, Yukiko; Hirabayashi, Takahiro; Kaneko, Ryosuke; Hamada, Shun; Kawamura, Yoshimi; Osada, Tomoharu; Yanagimachi, Ryuzo; Yagi, Takeshi

    2005-01-01

    Cloning of mice has been achieved by transferring nuclei of various types of somatic cell nuclei into enucleated oocytes. However, all attempts to produce live cloned offspring using the nuclei of neurons from adult cerebral cortex have failed. Previously we obtained cloned mice using the nuclei of neural cells collected from fetal cerebral cortex. Here, we attempted to generate cloned mice using differentiated neurons from the cerebral cortex of postnatal (day 0-4) mice. Although we were unable to obtain live cloned pups, many fetuses reached day 10.5 days of development. These fetuses showed various abnormalities such as spherical omission of the neuroepithelium, collapsed lumen of neural tube, and aberrant expressions of marker proteins of neurons. We produced chimeric mice in which some hair cells and kidney cells were originated from differentiated neurons. In chimeric fetuses, LacZ-positive donor cells were in all three germ cell layers. However, chimeras with large contribution of donor-derived cells were not obtained. These results indicate that nuclei of differentiated neurons have lost their developmental totipotency. In other words, the conventional nuclear transfer technique does not allow nuclei of differentiated neurons to undergo complete genomic reprogramming required for normal embryonic development.

  7. Functional connectivity of visual cortex in the blind follows retinotopic organization principles.

    Science.gov (United States)

    Striem-Amit, Ella; Ovadia-Caro, Smadar; Caramazza, Alfonso; Margulies, Daniel S; Villringer, Arno; Amedi, Amir

    2015-06-01

    Is visual input during critical periods of development crucial for the emergence of the fundamental topographical mapping of the visual cortex? And would this structure be retained throughout life-long blindness or would it fade as a result of plastic, use-based reorganization? We used functional connectivity magnetic resonance imaging based on intrinsic blood oxygen level-dependent fluctuations to investigate whether significant traces of topographical mapping of the visual scene in the form of retinotopic organization, could be found in congenitally blind adults. A group of 11 fully and congenitally blind subjects and 18 sighted controls were studied. The blind demonstrated an intact functional connectivity network structural organization of the three main retinotopic mapping axes: eccentricity (centre-periphery), laterality (left-right), and elevation (upper-lower) throughout the retinotopic cortex extending to high-level ventral and dorsal streams, including characteristic eccentricity biases in face- and house-selective areas. Functional connectivity-based topographic organization in the visual cortex was indistinguishable from the normally sighted retinotopic functional connectivity structure as indicated by clustering analysis, and was found even in participants who did not have a typical retinal development in utero (microphthalmics). While the internal structural organization of the visual cortex was strikingly similar, the blind exhibited profound differences in functional connectivity to other (non-visual) brain regions as compared to the sighted, which were specific to portions of V1. Central V1 was more connected to language areas but peripheral V1 to spatial attention and control networks. These findings suggest that current accounts of critical periods and experience-dependent development should be revisited even for primary sensory areas, in that the connectivity basis for visual cortex large-scale topographical organization can develop without any

  8. Effects of the Bee Venom Herbal Acupuncture on the Neurotransmitters of the Rat Brain Cortex

    Directory of Open Access Journals (Sweden)

    Hyoung-Seok Yun

    2001-02-01

    Full Text Available In order to study the effects of bee venom Herbal Acupuncture on neurotransmitters in the rat brain cortex, herbal acupuncture with bee venom group and normal saline group was performed at LI4 bilaterally of the rat. the average optical density of neurotransmitters from the cerebral cortex was analysed 30 minutes after the herbal aqupuncture, by the immunohistochemistry. The results were as follows: 1. The density of NADPH-diaphorase in bee venom group was increased significantly at the motor cortex, visual cortex, auditory cortex, cingulate cortex, retrosplenial cortex and perirhinal cortex compared to the normal saline group. 2. The average optical density of vasoactive intestinal peptide in bee venom group had significant changes at the insular cortex, retrosplenial cortex and perirhinal cortex, compared to the normal saline group. 3. The average optical density of neuropeptide-Y in bee venom group increased significantly at the visual cortex and cingulate cortex, compared to the normal saline group.

  9. A neuropsychological test of belief and doubt: Damage to ventromedial prefrontal cortex increases credulity for misleading advertising

    Directory of Open Access Journals (Sweden)

    Erik eAsp

    2012-07-01

    Full Text Available We have proposed the False Tagging Theory as a neurobiological model of belief and doubt processes. The theory posits that the prefrontal cortex is critical for normative doubt toward properly comprehended ideas or cognitions. Such doubt is important for advantageous decisions, for example in the financial and consumer purchasing realms. Here, using a neuropsychological approach, we put the False Tagging Theory to an empirical test, hypothesizing that focal damage to the ventromedial prefrontal cortex would cause a doubt deficit that would result in higher credulity and purchase intention for consumer products featured in misleading advertisements. We presented 8 consumer ads to 18 patients with focal brain damage to the ventromedial prefrontal cortex, 21 patients with focal brain damage outside the prefrontal cortex, and 10 demographically similar healthy comparison participants. Patients with ventromedial prefrontal cortex damage were (1 more credulous to misleading ads; and (2 showed the highest intention to purchase the products in the misleading advertisements, relative to patients with brain damage outside the prefrontal cortex and healthy comparison participants. The pattern of findings was obtained even for ads in which the misleading bent was corrected by a disclaimer. The evidence is consistent with our proposal that damage to the ventromedial prefrontal cortex disrupts a false tagging mechanism which normally produces doubt and skepticism for cognitive representations. We suggest that the disruption increases credulity for misleading information, even when the misleading information is corrected for by a disclaimer. This mechanism could help explain poor financial decision-making when persons with ventromedial prefrontal dysfunction (e.g., caused by neurological injury or aging are exposed to persuasive information.

  10. Spatiotemporal Profiles of Proprioception Processed by the Masseter Muscle Spindles in Rat Cerebral Cortex: An Optical Imaging Study

    Science.gov (United States)

    Fujita, Satoshi; Kaneko, Mari; Nakamura, Hiroko; Kobayashi, Masayuki

    2017-01-01

    Muscle spindles in the jaw-closing muscles, which are innervated by trigeminal mesencephalic neurons (MesV neurons), control the strength of occlusion and the position of the mandible. The mechanisms underlying cortical processing of proprioceptive information are critical to understanding how sensory information from the masticatory muscles regulates orofacial motor function. However, these mechanisms are mostly unknown. The present study aimed to identify the regions that process proprioception of the jaw-closing muscles using in vivo optical imaging with a voltage-sensitive dye in rats under urethane anesthesia. First, jaw opening that was produced by mechanically pulling down the mandible evoked an optical response, which reflects neural excitation, in two cortical regions: the most rostroventral part of the primary somatosensory cortex (S1) and the border between the ventral part of the secondary somatosensory cortex (S2) and the insular oral region (IOR). The kinetics of the optical signal, including the latency, amplitude, rise time, decay time and half duration, in the S1 region for the response with the largest amplitude were comparable to those in the region with the largest response in S2/IOR. Second, we visualized the regions responding to electrical stimulation of the masseter nerve, which activates both motor efferent fibers and somatosensory afferent fibers, including those that transmit nociceptive and proprioceptive information. Masseter nerve stimulation initially excited the rostral part of the S2/IOR region, and an adjacent region responded to jaw opening. The caudal part of the region showing the maximum response overlapped with the region responding to jaw opening, whereas the rostral part overlapped with the region responding to electrical stimulation of the maxillary and mandibular molar pulps. These findings suggest that proprioception of the masseter is processed in S1 and S2/IOR. Other sensory information, such as nociception, is

  11. Frequency tuning in the rat whisker barrel cortex revealed through RBC flux maps.

    Science.gov (United States)

    Kannurpatti, Sridhar S; Biswal, Bharat B

    2011-10-12

    The rodent whisker barrel cortex is ideal for studies related to sensory processing and neural plasticity in the brain. However, its small spatial dimensions challenge optical and other imaging technologies mapping cortical hemodynamics as functional resolution (the ability to spatially and selectively discriminate signals from microvascular compartments) limit measurement accuracy. To precisely map hemodynamic activity within the rat posteriomedial barrel subfield (PMBSF), we used functional Laser Doppler Imaging (fLDI) at high spatial resolution with optimized detection and analysis. In this configuration, we demonstrate prominent whisker deflection-induced fLDI hemodynamic responses from microvascular regions indicating the technique's specificity to smaller vessel compartments. Clusters of fLDI activation were confined within the PMBSF region during deflection of either single or all whiskers. Stereotaxic co-ordinate mapping was performed over all animals leading to an average maximum activity cluster at +5.3, -3.5 from the Bregma. The maximum activity cluster during all whisker stimulation combined with the principal activation cluster during deflection of the C1 whisker were used as a reference to characterize the fLDI maps within the PMBSF. fLDI activation area increased with the frequency of whisker deflection. In a quantitative analysis, we reveal the increase in the spatial extent of fLDI activation with stimulation frequency as spatially non-uniform with a bias towards the caudal region for low and rostral region for higher stimulation frequencies. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Brookhaven Linac Isotope Producer

    Data.gov (United States)

    Federal Laboratory Consortium — The Brookhaven Linac Isoptope Producer (BLIP)—positioned at the forefront of research into radioisotopes used in cancer treatment and diagnosis—produces commercially...

  13. 太湖夏季蓝藻水华期间产毒蓝藻基因型组成和种群丰度研究%Spatial Variations in Composition and Abundance of Microcystin-producing Cyanobacteria in Tai Lake in Summer

    Institute of Scientific and Technical Information of China (English)

    李大命; 孔繁翔; 叶琳琳; 于洋; 张民; 史小丽

    2011-01-01

    采用基于mcyA基因的PCR-DGGE和定量PCR分子技术,研究了太湖夏季蓝藻水华期间不同湖区水柱和表层底泥中产毒蓝藻基因型组成和种群丰度,同时利用高效液相色谱(HPLC)法测定了水体中微囊藻毒素(Microcystin,MC)3种异构体(MCLR、MC-YR、MC-RR)的浓度,为太湖蓝藻水华治理及其生态风险评估提供基础资料.结果表明,太湖产毒蓝藻有12种主要的基因型,不同湖区水体和底泥中基因型组成及其丰度存在差异,水体中基因型多样性高于底泥,所有样品中占优势的基因型是一致的,富营养化水平对产毒蓝藻群落结构有一定的影响.同时发现,水体中不同湖区产毒藻细胞种群丰度差异显著,富营养化水平高的湖区种群丰度也较高,底泥中产毒藻细胞种群丰度波动较小.水体中微囊藻毒素3种异构体中MC-LR浓度最高,其所占比例在湖区间有一定的差异,总微囊藻毒素浓度范围为0.54~1.08μg·L-1,部分湖区微囊藻毒素浓度超过WHO推荐的安全浓度阈值(<1.0μg·L-1),必须引起足够重视.%The community structures and abundances of microcystin-producing cyanobacteria in water column and surface sediment in Tai Lake were investigated using denaturing gradient gel electrophoresis (DGGE) and quantitative real time PCR(qPCR) techniques based on mcyA gene. Meanwhile, we measured the concentrations of three microcystin variants( microcystin-LR, microcystin-YR and microcystinRR) in water body by high performance liquid chromatography( HPLC ). DGGE profiles showed that there were 12 main mcyA genotypes in the toxic cyanobacteria of Tai Lake. The composition of microcystin-producing genotypes and the abundance of each genotype differ spatially in water column and surface sediment. Although mcyA genotype community was more diverse in water body than in sediment, the dominant mcyA genotype in all samples was the same. In addition, microcystin-producing community was affected by

  14. Pharmacokinetics of Maleic Acid as a Food Adulterant Determined by Microdialysis in Rat Blood and Kidney Cortex

    Directory of Open Access Journals (Sweden)

    Mei-Ling Hou

    2016-03-01

    Full Text Available Maleic acid has been shown to be used as a food adulterant in the production of modified starch by the Taiwan Food and Drug Administration. Due to the potential toxicity of maleic acid to the kidneys, this study aimed to develop an analytical method to investigate the pharmacokinetics of maleic acid in rat blood and kidney cortex. Multiple microdialysis probes were simultaneously inserted into the jugular vein and the kidney cortex for sampling after maleic acid administration (10 or 30 mg/kg, i.v., respectively. The pharmacokinetic results demonstrated that maleic acid produced a linear pharmacokinetic phenomenon within the doses of 10 and 30 mg/kg. The area under concentration versus time curve (AUC of the maleic acid in kidney cortex was 5-fold higher than that in the blood after maleic acid administration (10 and 30 mg/kg, i.v., respectively, indicating that greater accumulation of maleic acid occurred in the rat kidney.

  15. P1-27: Localizing Regions Activated by Surface Gloss in Macaque Visual Cortex by fMRI

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    Gouki Okazawa

    2012-10-01

    Full Text Available Surface properties of objects such as gloss provide important information about the states or materials of objects in our visual experiences. Previous studies have shown that there are cortical regions responding to shapes, colors, faces etc. in the macaque visual cortex. However, we still lack the information about where the surface properties are processed in the macaque visual cortex. In this study, we examined whether there are regions activated by surface gloss, an important surface property, in the macaque visual cortex by using functional magnetic resonance imaging (fMRI. We trained two monkeys to fixate on a small spot on the screen in MRI scanner, while the images of glossy and matte objects were presented. As a control condition for low-level image features, such as spatial frequency or luminance contrast, we generated scrambled images by locally randomizing the luminance phases of images using wavelet filters. By contrasting the responses to glossy images to those to matte and scrambled images, we found the activation in wide regions along the ventral visual pathway including V1, V2, V3, V4, and the posterior part of the inferior temporal (IT cortex. In one monkey, we also found the activations in the central part of IT cortex. In another control experiment, we manipulated the image contrasts and found that the responses in these regions cannot be explained simply by the image contrasts. These results suggest that surface gloss is processed along the ventral pathway and, in the IT cortex there are distinct regions processing surface gloss.

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

    Science.gov (United States)

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

    2011-08-01

    Modulations of sensory processing in early visual areas are thought to play an important role in conscious perception. To date, most empirical studies focused on effects occurring before or during visual presentation. By contrast, several emerging theories postulate that sensory processing and conscious visual perception may also crucially depend on late top-down influences, potentially arising after a visual display. To provide a direct test of this, we performed an fMRI study using a postcued report procedure. The ability to report a target at a specific spatial location in a visual display can be enhanced behaviorally by symbolic auditory postcues presented shortly after that display. Here we sh