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Sample records for category-selective extrastriate cortex

  1. Developmental continuity and change in responses to social and nonsocial categories in human extrastriate visual cortex

    OpenAIRE

    Pelphrey, Kevin A.; Juliana Lopez; James P. Morris

    2009-01-01

    It is well known that adult human extrastriate visual cortex contains areas that respond in a selective fashion to specific categories of visual stimuli. Three regions have been identified with particular regularity: the fusiform face area (FFA), which responds to faces more than to other objects; the parahippocampal place area (PPA), which responds selectively to images of houses, places, and visual scenes; and the extrastriate body area (EBA), which responds specifically to images of bodies...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1991-03-01

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

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

    Science.gov (United States)

    Haxby, J V; Grady, C L; Horwitz, B; Ungerleider, L G; Mishkin, M; Carson, R E; Herscovitch, P; Schapiro, M B; Rapoport, S I

    1991-01-01

    The existence and neuroanatomical locations of separate extrastriate visual pathways for object recognition and spatial localization were investigated in healthy young men. Regional cerebral blood flow was measured by positron emission tomography and bolus injections of H2(15)O, while subjects performed face matching, dot-location matching, or sensorimotor control tasks. Both visual matching tasks activated lateral occipital cortex. Face discrimination alone activated a region of occipitotemporal cortex that was anterior and inferior to the occipital area activated by both tasks. The spatial location task alone activated a region of lateral superior parietal cortex. Perisylvian and anterior temporal cortices were not activated by either task. These results demonstrate the existence of three functionally dissociable regions of human visual extrastriate cortex. The ventral and dorsal locations of the regions specialized for object recognition and spatial localization, respectively, suggest some homology between human and nonhuman primate extrastriate cortex, with displacement in human brain, possibly related to the evolution of phylogenetically newer cortical areas. Images PMID:2000370

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

    International Nuclear Information System (INIS)

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

  5. Distinct mechanisms of form-from-motion perception in human extrastriate cortex

    OpenAIRE

    Blanke, O; Brooks, A.; Mercier, M.; Spinelli, L.; Adriani, M.; Lavanchy, L.; Safran, A B; Landis, T

    2007-01-01

    The exquisite sensitivity of the human visual system to form-from-motion (FfM) cues is well documented. However, identifying the neural correlates of this sensitivity has proven difficult, particularly determining the respective contributions of different motion areas in extrastriate visual cortex. Here we measured visual FfM perception and more elementary visual motion (VM) perception in a group of 32 patients suffering from acute posterior brain damage, and performed MRI-based lesion analys...

  6. The Role of the Human Extrastriate Visual Cortex in Mirror Symmetry Discrimination: A TMS-Adaptation Study

    Science.gov (United States)

    Cattaneo, Zaira; Mattavelli, Giulia; Papagno, Costanza; Herbert, Andrew; Silvanto, Juha

    2011-01-01

    The human visual system is able to efficiently extract symmetry information from the visual environment. Prior neuroimaging evidence has revealed symmetry-preferring neuronal representations in the dorsolateral extrastriate visual cortex; the objective of the present study was to investigate the necessity of these representations in symmetry…

  7. Left dominance for language perception starts in the extrastriate cortex: An ERP and sLORETA study.

    Science.gov (United States)

    Selpien, Helene; Siebert, Carsten; Genc, Erhan; Beste, Christian; Faustmann, Pedro M; Güntürkün, Onur; Ocklenburg, Sebastian

    2015-09-15

    While it is well known that the left hemisphere is more efficient than the right in most tasks involving perception of speech stimuli, the neurophysiological pathways leading to these lateralised performance differences are as yet rather unclear. In particular, the question whether language lateralisation depends on semantic processing or is already evident in early perceptual stimulus processing has not been answered unequivocally. In the present study, we therefore recorded event-related potentials (ERPs) during tachistoscopic presentation of horizontally or vertically presented verbal stimuli in the left (LVF) and the right visual field (RVF). Participants were asked to indicate, whether the presented stimulus was a word or a non-word. On the behavioural level, participants showed stronger hemispheric asymmetries for horizontal, than for vertical stimulus presentation. In addition, ERP asymmetries were also modulated by stimulus presentation format, as the electrode by visual field interactions for P1 and N1 were stronger after vertical, than after horizontal stimulus presentation. Moreover, sLORETA revealed that ERP left-right asymmetries were mainly driven by the extrastriate cortex and reading-associated areas in the parietal cortex. Taken together, the present study shows electrophysiological support for the assumption that language lateralisation during speech perception arises from a left dominance for the processing of early perceptual stimulus aspects. PMID:26048428

  8. Shedding light on emotional perception: Interaction of brightness and semantic content in extrastriate visual cortex.

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    Schettino, Antonio; Keil, Andreas; Porcu, Emanuele; Müller, Matthias M

    2016-06-01

    The rapid extraction of affective cues from the visual environment is crucial for flexible behavior. Previous studies have reported emotion-dependent amplitude modulations of two event-related potential (ERP) components - the N1 and EPN - reflecting sensory gain control mechanisms in extrastriate visual areas. However, it is unclear whether both components are selective electrophysiological markers of attentional orienting toward emotional material or are also influenced by physical features of the visual stimuli. To address this question, electrical brain activity was recorded from seventeen male participants while viewing original and bright versions of neutral and erotic pictures. Bright neutral scenes were rated as more pleasant compared to their original counterpart, whereas erotic scenes were judged more positively when presented in their original version. Classical and mass univariate ERP analysis showed larger N1 amplitude for original relative to bright erotic pictures, with no differences for original and bright neutral scenes. Conversely, the EPN was only modulated by picture content and not by brightness, substantiating the idea that this component is a unique electrophysiological marker of attention allocation toward emotional material. Complementary topographic analysis revealed the early selective expression of a centro-parietal positivity following the presentation of original erotic scenes only, reflecting the recruitment of neural networks associated with sustained attention and facilitated memory encoding for motivationally relevant material. Overall, these results indicate that neural networks subtending the extraction of emotional information are differentially recruited depending on low-level perceptual features, which ultimately influence affective evaluations. PMID:26994832

  9. Contributions of early parallel pathways to extrastriate visual cortex in macaque monkey

    OpenAIRE

    Nassi, Jonathan J.

    2007-01-01

    Parallel Processing is a commonly used strategy in sensory systems of the mammalian brain. In the primate visual system, information is relayed from the retina to primary visual cortex (V1) along three parallel pathways: magnocellular (M), parvocellular (P), and koniocellular (K). These three pathways remain anatomically and physiologically distinct as they pass through M, P, and K layers of the lateral geniculate nucleus (LGN) of the thalamus and into V1, with the M pathway terminating prima...

  10. Extrastriate cortical areas activated during visual discrimination in man

    DEFF Research Database (Denmark)

    Roland, PE

    1981-01-01

    The regional cerebral blood flow (rCBF) was measured in 254 different regions of the human extrastriate cerebral cortex during rest and during visual shape discrimination. Visual shape discrimination increased the rCBF markedly in the frontal eye fields, the upper part of the prefrontal cortex, t...... lateral occipital cortex and the superior parietal cortex. Moderate increases of rCBF appeared in the inferotemporal cortex, the parietotemporo-occipital region and scattered in the lateral part of the prefrontal cortex....

  11. Dissociable effects of natural image structure and color on LFP and spiking activity in the lateral prefrontal cortex and extrastriate visual area V4

    OpenAIRE

    Liebe, Stefanie; Logothetis, Nikos K.; Rainer, Gregor

    2011-01-01

    Visual perception is mediated by unique contributions of the numerous brain regions that constitute the visual system. We performed simultaneous recordings of local field potentials (LFPs) and single unit activity (SUA) in areas V4 and lateral prefrontal cortex to characterize their contribution to visual processing. Here, we trained monkeys to identify natural images at different degradation levels in a visual recognition task. We parametrically varied color and structural information of nat...

  12. Dissociable effects of natural image structure and color on LFP and spiking activity in the lateral prefrontal cortex and extrastriate visual area V4.

    Science.gov (United States)

    Liebe, Stefanie; Logothetis, Nikos K; Rainer, Gregor

    2011-07-13

    Visual perception is mediated by unique contributions of the numerous brain regions that constitute the visual system. We performed simultaneous recordings of local field potentials (LFPs) and single unit activity (SUA) in areas V4 and lateral prefrontal cortex to characterize their contribution to visual processing. Here, we trained monkeys to identify natural images at different degradation levels in a visual recognition task. We parametrically varied color and structural information of natural images while the animals were performing the task. We show that the visual-evoked potential (VEP) of the LFP in V4 is highly sensitive to color, whereas the VEP in prefrontal cortex predominantly depends on image structure. When examining the relationship between VEP and SUA, we found that stimulus sensitivity for SUA was well predicted by the VEP in PF cortex but not in V4. Our results first reveal a functional specialization in both areas at the level of the LFP and further suggest that the degree to which mesoscopic signals, such as the VEP, are representative of the underlying SUA neural processing may be brain region specific within the context of visual recognition. PMID:21752998

  13. Activation of extrastriate and frontal cortical areas by visual words and word-like stimuli

    International Nuclear Information System (INIS)

    Visual presentation of words activates extrastriate regions of the occipital lobes of the brain. When analyzed by positron emission tomography (PET), certain areas in the left, medial extrastriate visual cortex were activated by visually presented pseudowords that obey English spelling rules, as well as by actual words. These areas were not activated by nonsense strings of letters or letter-like forms. Thus visual word form computations are based on learned distinctions between words and nonwords. In addition, during passive presentation of words, but not pseudowords, activation occurred in a left frontal area that is related to semantic processing. These findings support distinctions made in cognitive psychology and computational modeling between high-level visual and semantic computations on single words and describe the anatomy that may underlie these distinctions

  14. Relationship of Visual Cortex Function and Visual Acuity in Anisometropic Amblyopic Children

    Directory of Open Access Journals (Sweden)

    Chuanming Li, Lin Cheng, Qiongwu Yu, Bing Xie, Jian Wang

    2012-01-01

    Full Text Available Purpose: To detect the functional deficit of the visual cortex in anisometropic amblyopia children using functional magnetic resonance imaging (fMRI technique, and investigate the relationship between visual acuity and visual cortex function.Methods: Blood oxygenation level-dependent fMRI (BOLD-fMRI was performed in ten monocular anisometropic amblyopia children and ten normal controls. fMRI images were acquired in two runs with visual stimulation delivered separately through the sound and amblyopic eyes. Measurements were performed in cortical activation of striate and extrastriate areas at the occipital lobe. The relationship between cortex function and visual acuity was analyzed by Pearson partial analysis.Results: The activation areas of both the striate and extrastriate cortices in the amblyopic eyes were significantly lower than that of the sound fellow eyes. No relationship was found between the striate and extrastriate cortex activation. No relationship was found between the visual cortical activation of striate, extrastriate areas and visual acuity of anisometropic amblyopes.Conclusions: BOLD-fMRI revealed the independent striate and extrastriate cortical deficits in anisometropic amblyopes. In addition, the visual acuity lesion and the striate and extrastriate cortical deficits were not parallel, and results of fMRI examination have much potential value in the evaluation of amblyopia.

  15. Evidence for multiple extra-striate mechanisms behind perception of visual motion gradients.

    Science.gov (United States)

    Meso, Andrew Isaac; Hess, Robert F

    2012-07-01

    Perceiving motion patterns in visual scenes in which speed or motion direction varies over space while average luminance remains constant presents a processing task that requires at least two separate stages of neural spatio-temporal filtering. We have previously probed the transfer of information between these stages of filtering identifying a largely scale invariant process in which narrowband initial motion sensitive filters are coupled with a broad range of spatial frequencies of secondary filters, with an optimal coupling - in terms of optimal observer visual sensitivity - at a frequency ratio of around twelve. In the current work, we used the same stimulus to investigate the possible presence of multiple secondary filtering mechanisms and their associated bandwidths. Using a forced choice psychophysical task with both a detection and an identification component, we presented experimental blocks containing stimuli with one of two different modulator frequencies in each trial to measure the frequency difference at which the detection performance matched the identification of the frequency. We found that at a frequency differences of about 2.2 octaves, performance of both tasks was similar, and the processing could therefore be inferred to occur in independent frequency channels. The same observation was confirmed for stimuli presented at a longer viewing distance. We conclude that for the motion gradient stimuli, there are secondary filtering mechanisms with a moderately broad bandwidth of over 2 octaves that underlie our sensitivity for detecting motion gradients of different modulation frequency. These are likely to be implemented at least in part within the dorsal stream of extra-striate cortex. PMID:22659589

  16. Left extrastriate body area is sensitive to the meaning of symbolic gesture: evidence from fMRI repetition suppression.

    Science.gov (United States)

    Kubiak, Agnieszka; Króliczak, Gregory

    2016-01-01

    Functional magnetic resonance imaging (fMRI) adaptation (a.k.a. repetition suppression) paradigm was used to test if semantic information contained in object-related (transitive) pantomimes and communicative (intransitive) gestures is represented differently in the occipito-temporal cortex. Participants watched 2.75 s back-to-back videos where the meaning of gesture was either repeated or changed. The just observed (typically second) gesture was then imitated. To maintain participants' attention, some trials contained a single video. fMRI adaptation -signal decreases- for watching both movement categories were observed particularly in the lateral occipital cortex, including the extrastriate body area (EBA). Yet, intransitive (vs. transitive) gesture specific repetition suppression was found mainly in the left rostral EBA and caudal middle temporal gyrus- the rEBA/cMTG complex. Repetition enhancement (signal increase) was revealed in the precuneus. While the whole brain and region-of-interest analyses indicate that the precuneus is involved only in visuospatial action processing for later imitation, the common EBA repetition suppression discloses sensitivity to the meaning of symbolic gesture, namely the "semantic what" of actions. Moreover, the rEBA/cMTG suppression reveals greater selectivity for conventionalized communicative gesture. Thus, fMRI adaptation shows higher-order functions of EBA, its role in the semantic network, and indicates that its functional repertoire is wider than previously thought. PMID:27528007

  17. The Effect of Learning on the Function of Monkey Extrastriate Visual Cortex

    Directory of Open Access Journals (Sweden)

    Rainer Gregor

    2004-01-01

    Full Text Available One of the most remarkable capabilities of the adult brain is its ability to learn and continuously adapt to an ever-changing environment. While many studies have documented how learning improves the perception and identification of visual stimuli, relatively little is known about how it modifies the underlying neural mechanisms. We trained monkeys to identify natural images that were degraded by interpolation with visual noise. We found that learning led to an improvement in monkeys' ability to identify these indeterminate visual stimuli. We link this behavioral improvement to a learning-dependent increase in the amount of information communicated by V4 neurons. This increase was mediated by a specific enhancement in neural activity. Our results reveal a mechanism by which learning increases the amount of information that V4 neurons are able to extract from the visual environment. This suggests that V4 plays a key role in resolving indeterminate visual inputs by coordinated interaction between bottom-up and top-down processing streams.

  18. The effect of learning on the function of monkey extrastriate visual cortex.

    Directory of Open Access Journals (Sweden)

    Gregor Rainer

    2004-02-01

    Full Text Available One of the most remarkable capabilities of the adult brain is its ability to learn and continuously adapt to an ever-changing environment. While many studies have documented how learning improves the perception and identification of visual stimuli, relatively little is known about how it modifies the underlying neural mechanisms. We trained monkeys to identify natural images that were degraded by interpolation with visual noise. We found that learning led to an improvement in monkeys' ability to identify these indeterminate visual stimuli. We link this behavioral improvement to a learning-dependent increase in the amount of information communicated by V4 neurons. This increase was mediated by a specific enhancement in neural activity. Our results reveal a mechanism by which learning increases the amount of information that V4 neurons are able to extract from the visual environment. This suggests that V4 plays a key role in resolving indeterminate visual inputs by coordinated interaction between bottom-up and top-down processing streams.

  19. Do Object-Category Selective Regions in the Ventral Visual Stream Represent Perceived Distance Information?

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    Amit, Elinor; Mehoudar, Eyal; Trope, Yaacov; Yovel, Galit

    2012-01-01

    It is well established that scenes and objects elicit a highly selective response in specific brain regions in the ventral visual cortex. An inherent difference between these categories that has not been explored yet is their perceived distance from the observer (i.e. scenes are distal whereas objects are proximal). The current study aimed to test…

  20. A Computational Model of Extrastriate Visual Area MT on Motion Perception

    OpenAIRE

    Jiawei Xu; Shigang Yue

    2013-01-01

    Human vision system are sensitive to motion perception under complex scenes. Building motion attention models similar to human visual attention system should be very beneficial to computer vision and machine intelligence; meanwhile, it has been a challenging task due to the complexity of human brain and limited understanding of the mechanisms underlying the human vision system. This paper models the motion perception mechanisms in human extrastriate visual middle temporal area (MT) computatio...

  1. Ventral extra-striate cortical areas are required for optimal orientation averaging

    OpenAIRE

    Allen, Harriet A.; Humphreys, Glyn W.; Bridge, Holly

    2007-01-01

    We examined the ability of a previously well-studied patient with visual agnosia to compute the average orientation of elements in visual displays. In a structural MRI study, we show that the lesion is likely to involve a variety of ventral extra-striate areas, including V2, V3 and V4; however, the lesion does not extend dorsally. Subsequently we show that some ability to compute average orientation is spared, though there are limitations on the ability to scale the averaging process as a fun...

  2. The Extrastriate Body Area Computes Desired Goal States during Action Planning.

    Science.gov (United States)

    Zimmermann, Marius; Verhagen, Lennart; de Lange, Floris P; Toni, Ivan

    2016-01-01

    How do object perception and action interact at a neural level? Here we test the hypothesis that perceptual features, processed by the ventral visuoperceptual stream, are used as priors by the dorsal visuomotor stream to specify goal-directed grasping actions. We present three main findings, which were obtained by combining time-resolved transcranial magnetic stimulation and kinematic tracking of grasp-and-rotate object manipulations, in a group of healthy human participants (N = 22). First, the extrastriate body area (EBA), in the ventral stream, provides an initial structure to motor plans, based on current and desired states of a grasped object and of the grasping hand. Second, the contributions of EBA are earlier in time than those of a caudal intraparietal region known to specify the action plan. Third, the contributions of EBA are particularly important when desired and current object configurations differ, and multiple courses of actions are possible. These findings specify the temporal and functional characteristics for a mechanism that integrates perceptual processing with motor planning. PMID:27066535

  3. Color-tuned neurons are spatially clustered according to color preference within alert macaque posterior inferior temporal cortex

    OpenAIRE

    Conway, Bevil R.; Tsao, Doris Y

    2009-01-01

    Large islands of extrastriate cortex that are enriched for color-tuned neurons have recently been described in alert macaque using a combination of functional magnetic resonance imaging (fMRI) and single-unit recording. These millimeter-sized islands, dubbed “globs,” are scattered throughout the posterior inferior temporal cortex (PIT), a swath of brain anterior to area V3, including areas V4, PITd, and posterior TEO. We investigated the micro-organization of neurons within the globs. We used...

  4. Synchronization of oscillatory neuronal responses between striate and extrastriate visual cortical areas of the cat.

    OpenAIRE

    Engel, A K; Kreiter, A K; König, P; Singer, W.

    1991-01-01

    Recent studies have shown that neurons in area 17 of cat visual cortex display oscillatory responses which can synchronize across spatially separate orientation columns. Here, we demonstrate that unit responses recorded from the posteromedial lateral suprasylvian area, a visual association area specialized for the analysis of motion, also exhibit an oscillatory temporal structure. Cross-correlation analysis of unit responses reveals that cells in area 17 and the posteromedial lateral suprasyl...

  5. Perceptual expertise and top-down expectation of musical notation engages the primary visual cortex

    OpenAIRE

    Wong, Yetta Kwailing; Peng, Cynthia; Fratus, Kristyn N.; Woodman, Geoffrey F.; Gauthier, Isabel

    2014-01-01

    Most theories of visual processing propose that object recognition is achieved in higher visual cortex. However, we show that category selectivity for musical notation can be observed in the first event-related potential component called the C1 (measured 40-60ms after stimulus onset) with music-reading expertise. Moreover, the C1 note selectivity was observed only when the stimulus category was blocked but not when the stimulus category was randomized. Under blocking, the C1 activity for note...

  6. Evaluating the correspondence between face-, scene-, and object-selectivity and retinotopic organization within lateral occipitotemporal cortex

    Science.gov (United States)

    Silson, Edward H.; Groen, Iris I. A.; Kravitz, Dwight J.; Baker, Chris I.

    2016-01-01

    The organization of human lateral occipitotemporal cortex (lOTC) has been characterized largely according to two distinct principles: retinotopy and category-selectivity. Whereas category-selective regions were originally thought to exist beyond retinotopic maps, recent evidence highlights overlap. Here, we combined detailed mapping of retinotopy, using population receptive fields (pRF), and category-selectivity to examine and contrast the retinotopic profiles of scene- (occipital place area, OPA), face- (occipital face area, OFA) and object- (lateral occipital cortex, LO) selective regions of lOTC. We observe striking differences in the relationship each region has to underlying retinotopy. Whereas OPA overlapped multiple retinotopic maps (including V3A, V3B, LO1, and LO2), and LO overlapped two maps (LO1 and LO2), OFA overlapped almost none. There appears no simple consistent relationship between category-selectivity and retinotopic maps, meaning category-selective regions are not constrained spatially to retinotopic map borders consistently. The multiple maps that overlap OPA suggests it is likely not appropriate to conceptualize it as a single scene-selective region, whereas the inconsistency in any systematic map overlapping OFA suggests it may constitute a more uniform area. Beyond their relationship to retinotopy, all three regions evidenced strongly retinotopic voxels, with pRFs exhibiting a significant bias towards the contralateral lower visual field, despite differences in pRF size, contributing to an emerging literature suggesting this bias is present across much of lOTC. Taken together, these results suggest that whereas category-selective regions are not constrained to consistently contain ordered retinotopic maps, they nonetheless likely inherit retinotopic characteristics of the maps from which they draw information. PMID:27105060

  7. What does neural plasticity tell us about role of primary visual cortex (V1 in visual awareness?

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    JuhaSilvanto

    2011-01-01

    Full Text Available The complete loss of visual awareness resulting from a lesion to the primary visual cortex (V1 suggests that this region is indispensable for conscious visual perception. There are however a number cases of conscious perception in the absence of V1 which appear to challenge this conclusion. These include reports of patients with bilateral V1 lesions sustained at an early age whose conscious vision has spontaneously recovered, as well as stroke patients who have recovered some conscious vision with the help of rehabilitation programs. In addition, the phenomenon of hemianopic completion and percepts induced by brain stimulation suggest that V1 may not be necessary for conscious perception in all circumstances. Furthermore, that the visual abilities in the cat are associated with the recovery of normal extrastriate tuning properties rather than emulation of V1 functions suggests that there is nothing unique about the functional properties of this region in visual awareness. Rather, the dramatic effect of a V1 lesion on visual awareness may be due to its role in providing the majority of extrastriate visual input, the loss of which abolishes normal neural responsiveness throughout the visual cortex.

  8. A hierarchy of timescales explains distinct effects of local inhibition of primary visual cortex and frontal eye fields.

    Science.gov (United States)

    Cocchi, Luca; Sale, Martin V; L Gollo, Leonardo; Bell, Peter T; Nguyen, Vinh T; Zalesky, Andrew; Breakspear, Michael; Mattingley, Jason B

    2016-01-01

    Within the primate visual system, areas at lower levels of the cortical hierarchy process basic visual features, whereas those at higher levels, such as the frontal eye fields (FEF), are thought to modulate sensory processes via feedback connections. Despite these functional exchanges during perception, there is little shared activity between early and late visual regions at rest. How interactions emerge between regions encompassing distinct levels of the visual hierarchy remains unknown. Here we combined neuroimaging, non-invasive cortical stimulation and computational modelling to characterize changes in functional interactions across widespread neural networks before and after local inhibition of primary visual cortex or FEF. We found that stimulation of early visual cortex selectively increased feedforward interactions with FEF and extrastriate visual areas, whereas identical stimulation of the FEF decreased feedback interactions with early visual areas. Computational modelling suggests that these opposing effects reflect a fast-slow timescale hierarchy from sensory to association areas. PMID:27596931

  9. A single glance at natural face images generate larger and qualitatively different category-selective spatio-temporal signatures than other ecologically-relevant categories in the human brain.

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    Jacques, Corentin; Retter, Talia L; Rossion, Bruno

    2016-08-15

    Although humans discriminate natural images of faces from other categories at a single glance, clarifying the neural specificity and spatio-temporal dynamics of this process without low-level visual confounds remains a challenge. We recorded high-density scalp electroencephalogram while presenting natural images of various objects at a fast periodic rate (5.88images/s). In different stimulation sequences, numerous variable exemplars of three categories associated with cortical specialization in neuroimaging - faces, body parts, or houses - appeared every five images (5.88Hz/5=1.18Hz). In these fast periodic visual stimulation (FPVS) sequences, common low- and high-level visual processes between these categories and other objects are captured at the 5.88Hz frequency, while high-level category-selective responses are objectively quantified at the 1.18Hz frequency and harmonics. Category-selective responses differed quantitatively and qualitatively between faces, body parts and houses. First, they were much larger (2-4 times) for faces over the whole scalp. Second, specific and reliable scalp topographical maps of category-selective responses pointed to distinct principle neural sources for faces (ventral occipito-temporal), body parts (lateral occipito-temporal) and houses (dorso-medial occipital). Category-selective EEG responses were found at multiple time-windows from 110 to 600ms post-stimulus onset. Faces elicited the most complex spatio-temporal profile with up to four selective responses, although body parts and houses also elicited selective responses more complex than previously described. These observations indicate that a single glance at natural face images inserted in a rapid stream of natural objects generates a quantitatively and qualitatively unique category-selective spatio-temporal signature in occipito-temporal cortical areas of the human brain. PMID:27138205

  10. A Model of Representational Spaces in Human Cortex.

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

    2016-06-01

    Current models of the functional architecture of human cortex emphasize areas that capture coarse-scale features of cortical topography but provide no account for population responses that encode information in fine-scale patterns of activity. Here, we present a linear model of shared representational spaces in human cortex that captures fine-scale distinctions among population responses with response-tuning basis functions that are common across brains and models cortical patterns of neural responses with individual-specific topographic basis functions. We derive a common model space for the whole cortex using a new algorithm, searchlight hyperalignment, and complex, dynamic stimuli that provide a broad sampling of visual, auditory, and social percepts. The model aligns representations across brains in occipital, temporal, parietal, and prefrontal cortices, as shown by between-subject multivariate pattern classification and intersubject correlation of representational geometry, indicating that structural principles for shared neural representations apply across widely divergent domains of information. The model provides a rigorous account for individual variability of well-known coarse-scale topographies, such as retinotopy and category selectivity, and goes further to account for fine-scale patterns that are multiplexed with coarse-scale topographies and carry finer distinctions. PMID:26980615

  11. Perceptual expertise and top-down expectation of musical notation engages the primary visual cortex

    Science.gov (United States)

    Wong, Yetta Kwailing; Peng, Cynthia; Fratus, Kristyn N.; Woodman, Geoffrey F.; Gauthier, Isabel

    2014-01-01

    Most theories of visual processing propose that object recognition is achieved in higher visual cortex. However, we show that category selectivity for musical notation can be observed in the first event-related potential component called the C1 (measured 40-60ms after stimulus onset) with music-reading expertise. Moreover, the C1 note selectivity was observed only when the stimulus category was blocked but not when the stimulus category was randomized. Under blocking, the C1 activity for notes predicted individual music reading ability, and behavioral judgments of musical stimuli reflected music-reading skill. Our results challenge current theories of object recognition, indicating that the primary visual cortex can be selective for musical notation within the initial feedforward sweep of activity with perceptual expertise and with a testing context that is consistent with the expertise training, such as blocking the stimulus category for music reading. PMID:24666163

  12. A two-stage cascade model of BOLD responses in human visual cortex.

    Directory of Open Access Journals (Sweden)

    Kendrick N Kay

    Full Text Available Visual neuroscientists have discovered fundamental properties of neural representation through careful analysis of responses to controlled stimuli. Typically, different properties are studied and modeled separately. To integrate our knowledge, it is necessary to build general models that begin with an input image and predict responses to a wide range of stimuli. In this study, we develop a model that accepts an arbitrary band-pass grayscale image as input and predicts blood oxygenation level dependent (BOLD responses in early visual cortex as output. The model has a cascade architecture, consisting of two stages of linear and nonlinear operations. The first stage involves well-established computations-local oriented filters and divisive normalization-whereas the second stage involves novel computations-compressive spatial summation (a form of normalization and a variance-like nonlinearity that generates selectivity for second-order contrast. The parameters of the model, which are estimated from BOLD data, vary systematically across visual field maps: compared to primary visual cortex, extrastriate maps generally have larger receptive field size, stronger levels of normalization, and increased selectivity for second-order contrast. Our results provide insight into how stimuli are encoded and transformed in successive stages of visual processing.

  13. Cortical Connections of the Caudal Portion of Posterior Parietal Cortex in Prosimian Galagos.

    Science.gov (United States)

    Stepniewska, Iwona; Cerkevich, Christina M; Kaas, Jon H

    2016-06-01

    Posterior parietal cortex (PPC) of prosimian galagos includes a rostral portion (PPCr) where electrical stimulation evokes different classes of complex movements from different subregions, and a caudal portion (PPCc) where such stimulation fails to evoke movements in anesthetized preparations ( Stepniewska, Fang et al. 2009). We placed tracer injections into PPCc to reveal patterns of its cortical connections. There were widespread connections within PPCc as well as connections with PPCr and extrastriate visual areas, including V2 and V3. Weaker connections were with dorsal premotor cortex, and the frontal eye field. The connections of different parts of PPCc with visual areas were roughly retinotopic such that injections to dorsal PPCc labeled more neurons in the dorsal portions of visual areas, representing lower visual quadrant, and injections to ventral PPCc labeled more neurons in ventral portions of these visual areas, representing the upper visual quadrant. We conclude that much of the PPCc contains a crude representation of the contralateral visual hemifield, with inputs largely, but not exclusively, from higher-order visual areas that are considered part of the dorsal visuomotor processing stream. As in galagos, the caudal half of PPC was likely visual in early primates, with the rostral PPC half mediating sensorimotor functions. PMID:26088972

  14. Regulating prefrontal cortex activation

    DEFF Research Database (Denmark)

    Aznar, Susana; Klein, Anders Bue

    2013-01-01

    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 and the stria...

  15. A large-scale neurocomputational model of task-oriented behavior selection and working memory in prefrontal cortex.

    Science.gov (United States)

    Chadderdon, George L; Sporns, Olaf

    2006-02-01

    The prefrontal cortex (PFC) is crucially involved in the executive component of working memory, representation of task state, and behavior selection. This article presents a large-scale computational model of the PFC and associated brain regions designed to investigate the mechanisms by which working memory and task state interact to select adaptive behaviors from a behavioral repertoire. The model consists of multiple brain regions containing neuronal populations with realistic physiological and anatomical properties, including extrastriate visual cortical regions, the inferotemporal cortex, the PFC, the striatum, and midbrain dopamine (DA) neurons. The onset of a delayed match-to-sample or delayed nonmatch-to-sample task triggers tonic DA release in the PFC causing a switch into a persistent, stimulus-insensitive dynamic state that promotes the maintenance of stimulus representations within prefrontal networks. Other modeled prefrontal and striatal units select cognitive acceptance or rejection behaviors according to which task is active and whether prefrontal working memory representations match the current stimulus. Working memory task performance and memory fields of prefrontal delay units are degraded by extreme elevation or depletion of tonic DA levels. Analyses of cellular and synaptic activity suggest that hyponormal DA levels result in increased prefrontal activation, whereas hypernormal DA levels lead to decreased activation. Our simulation results suggest a range of predictions for behavioral, single-cell, and neuroimaging response data under the proposed task set and under manipulations of DA concentration. PMID:16494684

  16. Cognition without Cortex.

    Science.gov (United States)

    Güntürkün, Onur; Bugnyar, Thomas

    2016-04-01

    Assumptions on the neural basis of cognition usually focus on cortical mechanisms. Birds have no cortex, but recent studies in parrots and corvids show that their cognitive skills are on par with primates. These cognitive findings are accompanied by neurobiological discoveries that reveal avian and mammalian forebrains are homologous, and show similarities in connectivity and function down to the cellular level. But because birds have a large pallium, but no cortex, a specific cortical architecture cannot be a requirement for advanced cognitive skills. During the long parallel evolution of mammals and birds, several neural mechanisms for cognition and complex behaviors may have converged despite an overall forebrain organization that is otherwise vastly different. PMID:26944218

  17. 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.

  18. Reduced resting state functional connectivity of the somatosensory cortex predicts psychopathological symptoms in women with bulimia nervosa

    Directory of Open Access Journals (Sweden)

    Luca eLavagnino

    2014-08-01

    Full Text Available BackgroundAlterations in the resting state functional connectivity (rs-FC of several brain networks have been demonstrated in eating disorders. However, very few studies are currently available on brain network dysfunctions in bulimia nervosa (BN. The somatosensory network is central in processing body-related stimuli and it may be altered in BN. The present study therefore aimed to investigate rs-FC in the somatosensory network in bulimic women. MethodsSixteen medication-free women with BN (age=23±5 years and 18 matched controls (age=23±3 years underwent a functional magnetic resonance resting state scan and assessment of eating disorder symptoms. Within-network and seed-based functional connectivity analyses were conducted to assess rs-FC within the somatosensory network and to other areas of the brain. ResultsBN patients showed a decreased resting state functional connectivity both within the somatosensory network (t=9.0, df=1, P=0.005 and with posterior cingulate cortex (PCC and two visual areas (the right middle occipital gyrus and the right cuneus(P=0.05 corrected for multiple comparison. The region in the right middle occipital gyrus is implicated in body processing and is known as extrastriate body area, or EBA. The rs-FC of the left paracentral lobule with the EBA correlated with psychopathology measures like bulimia (r=-0.4; P=0.02 and interoceptive awareness (r=-0.4; P=0.01. Analyses were conducted using age, BMI (body mass index and depressive symptoms as covariates. ConclusionsOur findings show a specific alteration of the rs-FC of the somatosensory cortex in BN patients, which correlates with eating disorder symptoms. The connectivity between the somatosensory cortex and the EBA might be related to dysfunctions in body image processing. The results should be considered preliminary due to the small sample size.

  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. Atypical [corrected] participation of visual cortex during word processing in autism: an fMRI study of semantic decision.

    Science.gov (United States)

    Gaffrey, Michael S; Kleinhans, Natalia M; Haist, Frank; Akshoomoff, Natacha; Campbell, Ashley; Courchesne, Eric; Müller, Ralph-Axel

    2007-04-01

    Language delay and impairment are salient features of autism. More specifically, there is evidence of atypical semantic organization in autism, but the functional brain correlates are not well understood. The current study used functional MRI to examine activation associated with semantic category decision. Ten high-functioning men with autism spectrum disorder and 10 healthy control subjects matched for gender, handedness, age, and nonverbal IQ were studied. Participants indicated via button press response whether visually presented words belonged to a target category (tools, colors, feelings). The control condition required target letter detection in unpronounceable letter strings. Significant activation for semantic decision in the left inferior frontal gyrus (Brodmann areas 44 and 45) was found in the control group. Corresponding activation in the autism group was more limited, with smaller clusters in left inferior frontal areas 45 and 47. Autistic participants, however, showed significantly greater activation compared to controls in extrastriate visual cortex bilaterally (areas 18 and 19), which correlated with greater number of errors on the semantic task. Our findings suggest an important role of perceptual components (possibly visual imagery) during semantic decision, consistent with previous evidence of atypical lexicosemantic performance in autism. In the context of similar findings from younger typically developing children, our results suggest an immature pattern associated with inefficient processing, presumably due to atypical experiential embedding of word acquisition in autism. PMID:17336346

  1. MRI volumetry of prefrontal cortex

    Science.gov (United States)

    Sheline, Yvette I.; Black, Kevin J.; Lin, Daniel Y.; Pimmel, Joseph; Wang, Po; Haller, John W.; Csernansky, John G.; Gado, Mokhtar; Walkup, Ronald K.; Brunsden, Barry S.; Vannier, Michael W.

    1995-05-01

    Prefrontal cortex volumetry by brain magnetic resonance (MR) is required to estimate changes postulated to occur in certain psychiatric and neurologic disorders. A semiautomated method with quantitative characterization of its performance is sought to reliably distinguish small prefrontal cortex volume changes within individuals and between groups. Stereological methods were tested by a blinded comparison of measurements applied to 3D MR scans obtained using an MPRAGE protocol. Fixed grid stereologic methods were used to estimate prefrontal cortex volumes on a graphic workstation, after the images are scaled from 16 to 8 bits using a histogram method. In addition images were resliced into coronal sections perpendicular to the bicommissural plane. Prefrontal cortex volumes were defined as all sections of the frontal lobe anterior to the anterior commissure. Ventricular volumes were excluded. Stereological measurement yielded high repeatability and precision, and was time efficient for the raters. The coefficient of error was depression and schizophrenia can be efficiently assessed using this method.

  2. 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.

  3. Effect of temporal predictability on exogenous attentional modulation of feedforward processing in the striate cortex.

    Science.gov (United States)

    Dassanayake, Tharaka L; Michie, Patricia T; Fulham, Ross

    2016-07-01

    Non-informative peripheral visual cues facilitate extrastriate processing of targets [as indexed by enhanced amplitude of contralateral P1 event-related potential (ERP) component] presented at the cued location as opposed to those presented at uncued locations, at short cue-target stimulus onset asynchrony (SOA). Recently, two lines of research are emerging to suggest that the locus of attentional modulation is flexible and depends on 1) perceptual load and 2) temporal predictability of visual stimuli. We aimed to examine the effect of temporal predictability on attentional modulation of feed-forward activation of the striate cortex (as indexed by the C1 ERP component) by high-perceptual-load (HPL) stimuli. We conducted two ERP experiments where exogenously-cued HPL targets were presented under two temporal predictability conditions. In Experiment 1 [high-temporal-predictability (HTP) condition], 17 healthy subjects (age 18-26years) performed a line-orientation discrimination task on HPL targets presented in the periphery of the left upper or diagonally opposite right lower visual field, validly or invalidly cued by peripheral cues. SOA was fixed at 160ms. In Experiment 2 [low-temporal-predictability (LTP) condition], (n=10, age 19-36years) we retained HPL stimuli but randomly intermixed short-SOA trials with long-SOA (1000ms) trials in the task-blocks. In Experiment 1 and the short-SOA condition of the Experiment 2, validly-cued targets elicited significantly faster reaction times and larger contralateral P1, consistent with previous literature. A significant attentional enhancement of C1 amplitude was also observed in the HTP, but not LTP condition. The findings suggest that exogenous visual attention can facilitate the earliest stage of cortical processing under HTP conditions. PMID:27114044

  4. The distribution of category and location information across object-selective regions in human visual cortex.

    Science.gov (United States)

    Schwarzlose, Rebecca F; Swisher, Jascha D; Dang, Sabin; Kanwisher, Nancy

    2008-03-18

    Since Ungerleider and Mishkin [Underleider LG, Mishkin M (1982) Two cortical visual systems. Analysis of Visual Behavior, eds Ingle MA, Goodale MI, Masfield RJW (MIT Press, Cambridge, MA), pp 549-586] proposed separate visual pathways for processing object shape and location, steady progress has been made in characterizing the organization of the two kinds of information in extrastriate visual cortex in humans. However, to date, there has been no broad-based survey of category and location information across all major functionally defined object-selective regions. In this study, we used an fMRI region-of-interest (ROI) approach to identify eight regions characterized by their strong selectivity for particular object categories (faces, scenes, bodies, and objects). Participants viewed four types of stimuli (faces, scenes, bodies, and cars) appearing in each of three different spatial locations (above, below, or at fixation). Analyses based on the mean response and voxelwise patterns of response in each ROI reveal location information in almost all of the known object-selective regions. Furthermore, category and location information can be read out independently of one another such that most regions contain both position-invariant category information and category-invariant position information. Finally, we find substantially more location information in ROIs on the lateral than those on the ventral surface of the brain, even though these regions have equal amounts of category information. Although the presence of both location and category information in most object-selective regions argues against a strict physical separation of processing streams for object shape and location, the ability to extract position-invariant category information and category-invariant position information from the same neural population indicates that form and location information nonetheless remain functionally independent. PMID:18326624

  5. Canonical computations of cerebral cortex.

    Science.gov (United States)

    Miller, Kenneth D

    2016-04-01

    The idea that there is a fundamental cortical circuit that performs canonical computations remains compelling though far from proven. Here we review evidence for two canonical operations within sensory cortical areas: a feedforward computation of selectivity; and a recurrent computation of gain in which, given sufficiently strong external input, perhaps from multiple sources, intracortical input largely, but not completely, cancels this external input. This operation leads to many characteristic cortical nonlinearities in integrating multiple stimuli. The cortical computation must combine such local processing with hierarchical processing across areas. We point to important changes in moving from sensory cortex to motor and frontal cortex and the possibility of substantial differences between cortex in rodents vs. species with columnar organization of selectivity. PMID:26868041

  6. Food related processes in the insular cortex

    OpenAIRE

    Frank, Sabine; Kullmann, Stephanie; Veit, Ralf

    2013-01-01

    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 multim...

  7. Food related processes in the insular cortex

    OpenAIRE

    Sabine eFrank; Stephanie eKullmann; Ralf eVeit

    2013-01-01

    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 multimo...

  8. Addiction and the adrenal cortex

    OpenAIRE

    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 resumptio...

  9. Lateral occipitotemporal cortex (LOTC) activity is greatest while viewing dance compared to visualization and movement: learning and expertise effects.

    Science.gov (United States)

    Di Nota, Paula M; Levkov, Gabriella; Bar, Rachel; DeSouza, Joseph F X

    2016-07-01

    The lateral occipitotemporal cortex (LOTC) is comprised of subregions selectively activated by images of human bodies (extrastriate body area, EBA), objects (lateral occipital complex, LO), and motion (MT+). However, their role in motor imagery and movement processing is unclear, as are the influences of learning and expertise on its recruitment. The purpose of our study was to examine putative changes in LOTC activation during action processing following motor learning of novel choreography in professional ballet dancers. Subjects were scanned with functional magnetic resonance imaging up to four times over 34 weeks and performed four tasks: viewing and visualizing a newly learned ballet dance, visualizing a dance that was not being learned, and movement of the foot. EBA, LO, and MT+ were activated most while viewing dance compared to visualization and movement. Significant increases in activation were observed over time in left LO only during visualization of the unlearned dance, and all subregions were activated bilaterally during the viewing task after 34 weeks of performance, suggesting learning-induced plasticity. Finally, we provide novel evidence for modulation of EBA with dance experience during the motor task, with significant activation elicited in a comparison group of novice dancers only. These results provide a composite of LOTC activation during action processing of newly learned ballet choreography and movement of the foot. The role of these areas is confirmed as primarily subserving observation of complex sequences of whole-body movement, with new evidence for modification by experience and over the course of real world ballet learning. PMID:26960739

  10. Body selectivity in occipitotemporal cortex: Causal evidence.

    Science.gov (United States)

    Downing, Paul E; Peelen, Marius V

    2016-03-01

    Perception of others' bodies provides information that is useful for a number of important social-cognitive processes. Evidence from neuroimaging methods has identified focal cortical regions that are highly selective for perceiving bodies and body parts, including the extrastriate body area (EBA) and fusiform body area (FBA). Our understanding of the functional properties of these regions, and their causal contributions to behavior, has benefitted from the study of neuropsychological patients and particularly from investigations using transcranial magnetic stimulation (TMS). We review this evidence, focusing on TMS studies that are revealing of how (and when) activity in EBA contributes to detecting people in natural scenes; to resolving their body shape, movements, actions, individual parts, and identities; and to guiding goal-directed behavior. These findings are considered in reference to a framework for body perception in which the patterns of neural activity in EBA and FBA jointly serve to make explicit the elements of the visual scene that correspond to the body and its parts. These representations are modulated by other sources of information such as prior knowledge, and are shared with wider brain networks involved in many aspects of social cognition. PMID:26044771

  11. 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…

  12. The Piriform Cortex and Human Focal Epilepsy

    OpenAIRE

    Vaughan, David N.; Graeme D. Jackson

    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 releva...

  13. 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.

  14. In the Rat Cerebellar Cortex

    Directory of Open Access Journals (Sweden)

    Gokhan Ordek

    2014-10-01

    Full Text Available The changes of excitability in affected neural networks can be used as a marker to study the temporal course of traumatic brain injury (TBI. The cerebellum is an ideal platform to study brain injury mechanisms at the network level using the electrophysiological methods. Within its crystalline morphology, the cerebellar cortex contains highly organized topographical subunits that are defined by two main inputs, the climbing and mossy fibers. Here we demonstrate the use of cerebellar evoked potentials (EPs mediated through these afferent systems for monitoring the injury progression in a rat model of fluid percussion injury (FPI. A mechanical tap on the dorsal hand was used as a stimulus, and EPs were recorded from the paramedian lobule (PML of the posterior cerebellum via multi-electrode arrays (MEA. Post-injury evoked response amplitudes (EPAs were analyzed on a daily basis for one week and compared with pre-injury values. We found a trend of consistently decreasing EPAs in all nine animals, losing as much as 72±4% of baseline amplitudes measured before the injury. Notably, our results highlighted two particular time windows; the first 24 hours of injury in the acute period and day-3 to day-7 in the delayed period where the largest drops (~50% and 24% were observed in the EPAs. In addition, cross-correlations of spontaneous signals between electrode pairs declined (from 0.47±0.1 to 0.35±0.04, p<0.001 along with the EPAs throughout the week of injury. In support of the electrophysiological findings, immunohistochemical analysis at day-7 post-injury showed detectable Purkinje cell loss at low FPI pressures and more with the largest pressures used. Our results suggest that sensory evoked potentials recorded from the cerebellar surface can be a useful technique to monitor the course of cerebellar injury and identify the phases of injury progression even at mild levels.

  15. Auditory Connections and Functions of Prefrontal Cortex

    Directory of Open Access Journals (Sweden)

    BethanyPlakke

    2014-07-01

    Full Text Available The functional auditory system extends from the ears to the frontal lobes with successively more complex functions occurring as one ascends the hierarchy of the nervous system. Several areas of the frontal lobe receive afferents from both early and late auditory processing regions within the temporal lobe. Afferents from the early part of the cortical auditory system, the auditory belt cortex, which are presumed to carry information regarding auditory features of sounds, project to only a few prefrontal regions and are most dense in the ventrolateral prefrontal cortex (VLPFC. In contrast, projections from the parabelt and the rostral superior temporal gyrus (STG most likely convey more complex information and target a larger, widespread region of the prefrontal cortex. Neuronal responses reflect these anatomical projections as some prefrontal neurons exhibit responses to features in acoustic stimuli, while other neurons display task-related responses. For example, recording studies in non-human primates indicate that VLPFC is responsive to complex sounds including vocalizations and that VLPFC neurons in area 12/47 respond to sounds with similar acoustic morphology. In contrast, neuronal responses during auditory working memory involve a wider region of the prefrontal cortex. In humans, the frontal lobe is involved in auditory detection, discrimination, and working memory. Past research suggests that dorsal and ventral subregions of the prefrontal cortex process different types of information with dorsal cortex processing spatial/visual information and ventral cortex processing non-spatial/auditory information. While this is apparent in the non-human primate and in some neuroimaging studies, most research in humans indicates that specific task conditions, stimuli or previous experience may bias the recruitment of specific prefrontal regions, suggesting a more flexible role for the frontal lobe during auditory cognition.

  16. Motor cortex neuroplasticity following brachial plexus transfer

    Directory of Open Access Journals (Sweden)

    Michael Biggs

    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.

  17. Cortex commands the performance of skilled movement.

    Science.gov (United States)

    Guo, Jian-Zhong; Graves, Austin R; Guo, Wendy W; Zheng, Jihong; Lee, Allen; Rodríguez-González, Juan; Li, Nuo; Macklin, John J; Phillips, James W; Mensh, Brett D; Branson, Kristin; Hantman, Adam W

    2015-01-01

    Mammalian cerebral cortex is accepted as being critical for voluntary motor control, but what functions depend on cortex is still unclear. Here we used rapid, reversible optogenetic inhibition to test the role of cortex during a head-fixed task in which mice reach, grab, and eat a food pellet. Sudden cortical inhibition blocked initiation or froze execution of this skilled prehension behavior, but left untrained forelimb movements unaffected. Unexpectedly, kinematically normal prehension occurred immediately after cortical inhibition, even during rest periods lacking cue and pellet. This 'rebound' prehension was only evoked in trained and food-deprived animals, suggesting that a motivation-gated motor engram sufficient to evoke prehension is activated at inhibition's end. These results demonstrate the necessity and sufficiency of cortical activity for enacting a learned skill. PMID:26633811

  18. 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.

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

    Directory of Open Access Journals (Sweden)

    KensakuMori

    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.

  20. 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 t...

  1. Functional genomics of early cortex patterning

    OpenAIRE

    Chambers, David; Fishell, Gord

    2006-01-01

    Several lines of evidence have illuminated the fundamental developmental principles involved in establishing and implementing pattern formation in the mammalian neocortex. A recent study has sought to unravel the underlying genetic control of cortex patterning by elucidating the transcriptional profile of discrete neocortical regions.

  2. The insular cortex: a comparative perspective.

    Science.gov (United States)

    Butti, Camilla; Hof, Patrick R

    2010-06-01

    The human insular cortex is involved in a variety of viscerosensory, visceromotor, and interoceptive functions, and plays a role in complex processes such as emotions, music, and language. Across mammals, the insula has considerable morphologic variability. We review the structure and connectivity of the insula in laboratory animals (mouse, domestic cat, macaque monkey), and we present original data on the morphology and cytoarchitecture of insular cortex in less common species including a large carnivore (the Atlantic walrus, Odobenus rosmarus), two artiodactyls (the pigmy hippopotamus, Hexaprotodon liberiensis, and the Western bongo, Tragelaphus eurycerus), two cetaceans (the beluga whale, Delphinapterus leucas, and the minke whale, Balaenoptera acutorostrata), and a sirenian (the Florida manatee, Trichechus manatus latirostris). The insula shows substantial variability in shape, extent, and gyral and sulcal patterns, as well as differences in laminar organization, cellular specialization, and structural association with the claustrum. Our observations reveal that the insular cortex is extremely variable among mammals. These differences could be related to the role exerted by specific and selective pressures on cortical structure during evolution. We conclude that it is not possible to identify a general model of organization for the mammalian insular cortex. PMID:20512368

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

    DEFF Research Database (Denmark)

    Ioannides, Andreas A; Liu, Lichan; Poghosyan, Vahe;

    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 magnetoencephalog...... evidence from MEG that in blind subjects, tactile information is routed from primary somatosensory to occipital cortex via the posterior parietal cortex....

  4. 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 ...

  5. Uptake of trimethoprim by renal cortex.

    Science.gov (United States)

    Cacini, W; Myre, S A

    1985-10-01

    The purpose of this study was to examine the mechanisms involved in the uptake of the urinary antibacterial drug trimethoprim by incubated slices of rat renal cortex. Concentration-dependent studies of the uptake process demonstrated that a saturable component was involved. The results of inhibitor studies as well as the time-course pattern support the conclusion that at least two processes are involved in the uptake of trimethoprim. These include active transport via the organic cation system, accounting for about 40% of the total uptake, and a second component that continues to operate under conditions of inhibited cellular metabolism. Chromatographic examination of post-incubation bathing medium and slice extracts failed to demonstrate renal cortex metabolism of trimethoprim. PMID:4052093

  6. Encoding frequency contrast in primate auditory cortex

    OpenAIRE

    Malone, Brian J.; Scott, Brian H.; Semple, Malcolm N.

    2014-01-01

    Changes in amplitude and frequency jointly determine much of the communicative significance of complex acoustic signals, including human speech. We have previously described responses of neurons in the core auditory cortex of awake rhesus macaques to sinusoidal amplitude modulation (SAM) signals. Here we report a complementary study of sinusoidal frequency modulation (SFM) in the same neurons. Responses to SFM were analogous to SAM responses in that changes in multiple parameters defining SFM...

  7. Inhibition in the Human Auditory Cortex

    OpenAIRE

    Koji Inui; Kei Nakagawa; Makoto Nishihara; Eishi Motomura; Ryusuke Kakigi

    2016-01-01

    Despite their indispensable roles in sensory processing, little is known about inhibitory interneurons in humans. Inhibitory postsynaptic potentials cannot be recorded non-invasively, at least in a pure form, in humans. We herein sought to clarify whether prepulse inhibition (PPI) in the auditory cortex reflected inhibition via interneurons using magnetoencephalography. An abrupt increase in sound pressure by 10 dB in a continuous sound was used to evoke the test response, and PPI was observe...

  8. Dopamine gates sensory representations in cortex

    OpenAIRE

    Eshel, Neir; Tian, Ju

    2014-01-01

    The prefrontal cortex (PFC) maintains information about relevant sensory stimuli, in a process thought to rely on dopamine release. In a recent paper, Jacob et al. (J Neurosci 33: 13724–13734, 2013) demonstrated one way in which dopamine might facilitate this process. The authors recorded from PFC neurons in monkeys during local application of dopamine. They found that dopamine increases the gain of sensory-evoked responses in putative pyramidal neurons in PFC, potentially by inhibiting local...

  9. Odorant Category Profile Selectivity of Olfactory Cortex

    OpenAIRE

    Yoshida, Ikue; Mori, Kensaku

    2007-01-01

    The olfactory cortex receives converging axonal inputs from many mitral and tufted cells in the olfactory bulb. Recent studies indicate that single cortical neurons integrate signals from diverse odorants. However, there remains a basic question, namely, the signals from which kinds of odorants are integrated by the individual cortical neurons? The present study examined the possibility that some cortical neurons integrate signals from distinct component odorants of natural foods because indi...

  10. Color contrast processing in human striate cortex

    OpenAIRE

    Kentridge, R. W.; Heywood, C. A.; Weiskrantz, L.

    2007-01-01

    Color constancy refers to the unchanging nature of the perceived color of an object despite considerable variation in the wavelength composition of the light illuminating it. The color contrasts between objects and their backgrounds play a crucial role in color constancy. We tested a patient whose right striate cortex had been removed and demonstrated that he made no use of color contrast in judging color appearance but instead made judgments based simply on wavelength comparison. This was sh...

  11. 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.

  12. Activity of the motor cortex during scratching.

    Science.gov (United States)

    Sirota, Mikhail G; Pavlova, Galina A; Beloozerova, Irina N

    2006-02-01

    In awake cats sitting with the head restrained, scratching was evoked using stimulation of the ear. Cats scratched the shoulder area, consistently failing to reach the ear. Kinematics of the hind limb movements and the activity of ankle muscles, however, were similar to those reported earlier in unrestrained cats. The activity of single neurons in the hind limb representation of the motor cortex, including pyramidal tract neurons (PTNs), was examined. During the protraction stage of the scratch response, the activity in 35% of the neurons increased and in 50% decreased compared with rest. During the rhythmic stage, the motor cortex population activity was approximately two times higher compared with rest, because the activity of 53% of neurons increased and that of 33% decreased in this stage. The activity of 61% of neurons was modulated in the scratching rhythm. The average depth of frequency modulation was 12.1 +/- 5.3%, similar to that reported earlier for locomotion. The phases of activity of different neurons were approximately evenly distributed over the scratch cycle. There was no simple correlation between resting receptive field properties and the activity of neurons during the scratch response. We conclude that the motor cortex participates in both the protraction and the rhythmic stages of the scratch response. PMID:16236789

  13. Connectivity changes underlying neurofeedback training of visual cortex activity.

    Directory of Open Access Journals (Sweden)

    Frank Scharnowski

    Full Text Available Neurofeedback based on real-time functional magnetic resonance imaging (fMRI is a new approach that allows training of voluntary control over regionally specific brain activity. However, the neural basis of successful neurofeedback learning remains poorly understood. Here, we assessed changes in effective brain connectivity associated with neurofeedback training of visual cortex activity. Using dynamic causal modeling (DCM, we found that training participants to increase visual cortex activity was associated with increased effective connectivity between the visual cortex and the superior parietal lobe. Specifically, participants who learned to control activity in their visual cortex showed increased top-down control of the superior parietal lobe over the visual cortex, and at the same time reduced bottom-up processing. These results are consistent with efficient employment of top-down visual attention and imagery, which were the cognitive strategies used by participants to increase their visual cortex activity.

  14. Magnetic Resonance and adrenal cortex pathology

    International Nuclear Information System (INIS)

    M.R.I. allows a good delineation of adrenals, due to the high contrast with fat and to the use of frontal planes. On post operative adrenal lesions samples the lipid percentages, high in normal and hyperplasic glands, was still high in most benign adenomas, and very low (under 5 %) in adrenal carcinomas. MRI, with Dixon sequence, allows to evaluate this lipid percentage in adrenal lesions. Post-operative controls show a good agreement between in vivo and in vitro measurements. This simple technique should allow to discriminate between malignant and benign adrenal cortex lesions

  15. What does spatial alternation tell us about retrosplenial cortex function?

    OpenAIRE

    Andrew John Dudley Nelson

    2015-01-01

    The retrosplenial cortex supports navigation, but there are good reasons to suppose that the retrosplenial cortex has a very different role in spatial memory from that of the hippocampus and anterior thalamic nuclei. For example, retrosplenial lesions appear to have little or no effect on standard tests of spatial alternation. To examine these differences, the current study sought to determine whether the retrosplenial cortex is important for just one spatial cue type (e.g. allocentric, direc...

  16. What does spatial alternation tell us about retrosplenial cortex function?

    OpenAIRE

    Nelson, Andrew J.D.; Powell, Anna L.; Holmes, Joshua D.; Vann, Seralynne D.; Aggleton, John. P.

    2015-01-01

    The retrosplenial cortex supports navigation, but there are good reasons to suppose that the retrosplenial cortex has a very different role in spatial memory from that of the hippocampus and anterior thalamic nuclei. For example, retrosplenial lesions appear to have little or no effect on standard tests of spatial alternation. To examine these differences, the current study sought to determine whether the retrosplenial cortex is important for just one spatial cue type (e.g., allocentric, dire...

  17. Complementary sensory and associative microcircuitry in primary olfactory cortex

    OpenAIRE

    Wiegand, H.F.; Beed, P.; Bendels, M.H.; Leibold, C.; Schmitz, D; Johenning, F.W.

    2011-01-01

    The three-layered primary olfactory (piriform) cortex is the largest component of the olfactory cortex. Sensory and intracortical inputs converge on principal cells in the anterior piriform cortex (aPC). We characterize organization principles of the sensory and intracortical microcircuitry of layer II and III principal cells in acute slices of rat aPC using laser-scanning photostimulation and fast two-photon population Ca(2+) imaging. Layer II and III principal cells are set up on a superfic...

  18. Measurements of evoked electroencephalograph by transcranial magnetic stimulation applied to motor cortex and posterior parietal cortex

    Science.gov (United States)

    Iwahashi, Masakuni; Koyama, Yohei; Hyodo, Akira; Hayami, Takehito; Ueno, Shoogo; Iramina, Keiji

    2009-04-01

    To investigate the functional connectivity, the evoked potentials by stimulating at the motor cortex, the posterior parietal cortex, and the cerebellum by transcranial magnetic stimulation (TMS) were measured. It is difficult to measure the evoked electroencephalograph (EEG) by the magnetic stimulation because of the large artifact induced by the magnetic pulse. We used an EEG measurement system with sample-and-hold circuit and an independent component analysis to eliminate the electromagnetic interaction emitted from TMS. It was possible to measure EEG signals from all electrodes over the head within 10 ms after applying the TMS. When the motor area was stimulated by TMS, the spread of evoked electrical activity to the contralateral hemisphere was observed at 20 ms after stimulation. However, when the posterior parietal cortex was stimulated, the evoked electrical activity to the contralateral hemisphere was not observed. When the cerebellum was stimulated, the cortical activity propagated from the stimulated point to the frontal area and the contralateral hemisphere at around 20 ms after stimulation. These results suggest that the motor area has a strong interhemispheric connection and the posterior parietal cortex has no interhemispheric connection.

  19. 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. PMID:27318139

  20. 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...

  1. 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.

  2. Conceptual size representation in ventral visual cortex.

    Science.gov (United States)

    Gabay, Shai; Kalanthroff, Eyal; Henik, Avishai; Gronau, Nurit

    2016-01-29

    Recent findings suggest that visual objects may be mapped along the ventral occipitotemporal cortex according to their real-world size (Konkle and Oliva, 2012). It has been argued that such mapping does not reflect an abstract, conceptual size representation, but rather the visual or functional properties associated with small versus big real-world objects. To determine whether a more abstract conceptual size representation may affect visual cortical activation we used meaningless geometrical shapes, devoid of semantic or functional associations, which were associated with specific size representations by virtue of extensive training. Following training, participants underwent functional magnetic resonance imaging (fMRI) scanning while performing a conceptual size comparison task on the geometrical shapes. In addition, a size comparison task was conducted for numeral digits denoting small and big numbers. A region-of-interest analysis revealed larger blood oxygenation level dependent (BOLD) responses for conceptually 'big' than for conceptually 'small' shapes, as well as for big versus small numbers, within medial (parahippocampal place area, PPA) and lateral (occipital place area, OPA) place-selective regions. Processing of the 'big' visual shapes further elicited enhanced activation in early visual cortex, possibly reflecting top-down projections from PPA. By using arbitrary shapes and numbers we minimized visual, categorical, or functional influences on fMRI measurement, providing evidence for a possible neural mechanism underlying the representation of abstract conceptual size within the ventral visual stream. PMID:26731198

  3. 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.

  4. Combination of blood oxygen level–dependent functional magnetic resonance imaging and visual evoked potential recordings for abnormal visual cortex in two types of amblyopia

    Science.gov (United States)

    Wang, Xinmei; Cui, Dongmei; Zheng, Ling; Yang, Xiao; Yang, Hui

    2012-01-01

    Purpose To elucidate the different neuromechanisms of subjects with strabismic and anisometropic amblyopia compared with normal vision subjects using blood oxygen level–dependent functional magnetic resonance imaging (BOLD-fMRI) and pattern-reversal visual evoked potential (PR-VEP). Methods Fifty-three subjects, age range seven to 12 years, diagnosed with strabismic amblyopia (17 cases), anisometropic amblyopia (20 cases), and normal vision (16 cases), were examined using the BOLD-fMRI and PR-VEP of UTAS-E3000 techniques. Cortical activation by binocular viewing of reversal checkerboard patterns was examined in terms of the calcarine region of interest (ROI)-based and spatial frequency–dependent analysis. The correlation of cortical activation in fMRI and the P100 amplitude in VEP were analyzed using the SPSS 12.0 software package. Results In the BOLD-fMRI procedure, reduced areas and decreased activation levels were found in Brodmann area (BA) 17 and other extrastriate areas in subjects with amblyopia compared with the normal vision group. In general, the reduced areas mainly resided in the striate visual cortex in subjects with anisometropic amblyopia. In subjects with strabismic amblyopia, a more significant cortical impairment was found in bilateral BA 18 and BA 19 than that in subjects with anisometropic amblyopia. The activation by high-spatial-frequency stimuli was reduced in bilateral BA 18 and 19 as well as BA 17 in subjects with anisometropic amblyopia, whereas the activation was mainly reduced in BA 18 and BA 19 in subjects with strabismic amblyopia. These findings were further confirmed by the ROI-based analysis of BA 17. During spatial frequency–dependent VEP detection, subjects with anisometropic amblyopia had reduced sensitivity for high spatial frequency compared to subjects with strabismic amblyopia. The cortical activation in fMRI with the calcarine ROI-based analysis of BA 17 was significantly correlated with the P100 amplitude in VEP

  5. Anodic or cathodic motor cortex stimulation for pain?

    NARCIS (Netherlands)

    Holsheimer, J.; Manola, L.

    2006-01-01

    Objective. In motor cortex stimulation (MCS) for central and trigeminal pain Resume leads are placed epidurally over the motor and sensory cortex. Several bipolar combinations are used to identify the cortical target corresponding to the painful body segment. The cathode giving the largest motor r

  6. Ventromedial prefrontal cortex mediates visual attention during facial emotion recognition

    OpenAIRE

    Wolf, Richard C.; Philippi, Carissa L.; Motzkin, Julian C.; Baskaya, Mustafa K.; Koenigs, Michael

    2014-01-01

    The ventromedial prefrontal cortex plays a crucial role in regulating emotion and social behavior, yet the precise mechanisms underlying this function remain unclear. Using eye-tracking in patients with brain lesions, Wolf et al. show that ventromedial prefrontal cortex is critical for directing visual attention during facial emotion recognition.

  7. Olfactocentric Paralimbic Cortex Morphology in Adolescents with Bipolar Disorder

    Science.gov (United States)

    Wang, Fei; Kalmar, Jessica H.; Womer, Fay Y.; Edmiston, Erin E.; Chepenik, Lara G.; Chen, Rachel; Spencer, Linda; Blumberg, Hilary P.

    2011-01-01

    The olfactocentric paralimbic cortex plays a critical role in the regulation of emotional and neurovegetative functions that are disrupted in core features of bipolar disorder. Adolescence is thought to be a critical period in both the maturation of the olfactocentric paralimbic cortex and in the emergence of bipolar disorder pathology. Together,…

  8. An approach to visual cortex operation: optical neuron model

    OpenAIRE

    Martín Pereda, José Antonio; González Marcos, Ana

    1994-01-01

    Several works have been published in the last years concerning the modelling and implementation of the visual cortex operation. Most of them present simple neurons with just two different responses, namely inhibitory and excitatory. Some of the different types of visual cortex cells are simulated in these configurations.

  9. Metaphorically Feeling: Comprehending Textural Metaphors Activates Somatosensory Cortex

    Science.gov (United States)

    Lacey, Simon; Stilla, Randall; Sathian, K.

    2012-01-01

    Conceptual metaphor theory suggests that knowledge is structured around metaphorical mappings derived from physical experience. Segregated processing of object properties in sensory cortex allows testing of the hypothesis that metaphor processing recruits activity in domain-specific sensory cortex. Using functional magnetic resonance imaging…

  10. The dorsolateral prefrontal cortex, schizophrenia and PET

    International Nuclear Information System (INIS)

    Central neurophysiology can be measured with PET. These measurements are providing insights into the regional abnormalities associated with schizophrenia. Cohorts of schizophrenic subjects have been studied cross-sectionally in attempts to identify common regional deficits. More recently the advent of fast dynamic measurements of regional cerebral blood flow have allowed rapid serial measurements in the same subject in different brain states (activation studies). These complementary approaches are based upon, and are interpreted with reference to, a number of methodological considerations and underlying hypotheses. The key hypotheses underpining cross-sectional and activation studies are discussed within the framework of the lesion model and functional anatomy models of brain function. This brief review of some assumptions, ideas and methodological constraints is illustrated with empirical data implicating the dorsolateral prefrontal cortex in schizophrenic symptoms. (author)

  11. Patterning the cerebral cortex: traveling with morphogens.

    Science.gov (United States)

    Borello, Ugo; Pierani, Alessandra

    2010-08-01

    The neocortex represents the brain structure that has been subjected to a major expansion in its relative size during the course of mammalian evolution. An exquisite coordination of appropriate growth of competent territories along multiple axes and their spatial patterning is required for regionalization of the cortical primordium and the formation of functional areas. The achievement of such a highly complex architecture relies on a precise orchestration of the proliferation of progenitors, onset of neurogenesis, spatio-temporal generation of distinct cell types and control of their migration. We will review recent work on alternative molecular mechanisms that, via the migration of signaling cells/structures, participate in coordinating growth and spatial patterning in the developing cerebral cortex. By integrating temporal and spatial parameters as well as absolute levels of signaling this novel strategy might represent a general mechanism for long-range patterning in large structures, in addition to the passive diffusion of morphogens. PMID:20542680

  12. Spindle Bursts in Neonatal Rat Cerebral Cortex.

    Science.gov (United States)

    Yang, Jenq-Wei; Reyes-Puerta, Vicente; Kilb, Werner; Luhmann, Heiko J

    2016-01-01

    Spontaneous and sensory evoked spindle bursts represent a functional hallmark of the developing cerebral cortex in vitro and in vivo. They have been observed in various neocortical areas of numerous species, including newborn rodents and preterm human infants. Spindle bursts are generated in complex neocortical-subcortical circuits involving in many cases the participation of motor brain regions. Together with early gamma oscillations, spindle bursts synchronize the activity of a local neuronal network organized in a cortical column. Disturbances in spindle burst activity during corticogenesis may contribute to disorders in cortical architecture and in the activity-dependent control of programmed cell death. In this review we discuss (i) the functional properties of spindle bursts, (ii) the mechanisms underlying their generation, (iii) the synchronous patterns and cortical networks associated with spindle bursts, and (iv) the physiological and pathophysiological role of spindle bursts during early cortical development. PMID:27034844

  13. Early GABAergic circuitry in the cerebral cortex.

    Science.gov (United States)

    Luhmann, Heiko J; Kirischuk, Sergei; Sinning, Anne; Kilb, Werner

    2014-06-01

    In the cerebral cortex GABAergic signaling plays an important role in regulating early developmental processes, for example, neurogenesis, migration and differentiation. Transient cell populations, namely Cajal-Retzius in the marginal zone and thalamic input receiving subplate neurons, are integrated as active elements in transitory GABAergic circuits. Although immature pyramidal neurons receive GABAergic synaptic inputs already at fetal stages, they are integrated into functional GABAergic circuits only several days later. In consequence, GABAergic synaptic transmission has only a minor influence on spontaneous network activity during early corticogenesis. Concurrent with the gradual developmental shift of GABA action from excitatory to inhibitory and the maturation of cortical synaptic connections, GABA becomes more important in synchronizing neuronal network activity. PMID:24434608

  14. 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

    2016-03-29

    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 τM) in the actomyosin sets the timescale of large-scale deformation of the cortex. Similarly, the characteristic length of stress propagation (the hydrodynamic length λ) 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 directly from laser ablation experiments. For this we investigate the cortical response to laser ablation in the one-cell-stage Caenorhabditis 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 τM, the hydrodynamic length λ, the ratio of active stress ζΔμ, and per-area friction γ, 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. Our method provides 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 into the active mechanics processes that govern tissue-scale morphogenesis. PMID

  15. Preferential Encoding of Visual Categories in Parietal Cortex Compared to Prefrontal Cortex

    OpenAIRE

    Swaminathan, Sruthi K.; Freedman, David J

    2012-01-01

    The ability to recognize the behavioral significance, or category membership, of sensory stimuli is critical for interpreting the meaning of events in our environment. Prior neurophysiological studies of visual categorization found categorical representations of stimuli in prefrontal cortex (PFC), an area closely associated with cognitive and executive functions. Recent studies have also identified neuronal category signals in parietal areas typically associated with visual-spatial processing...

  16. Forelimb training drives transient map reorganization in ipsilateral motor cortex.

    Science.gov (United States)

    Pruitt, David T; Schmid, Ariel N; Danaphongse, Tanya T; Flanagan, Kate E; Morrison, Robert A; Kilgard, Michael P; Rennaker, Robert L; Hays, Seth A

    2016-10-15

    Skilled motor training results in reorganization of contralateral motor cortex movement representations. The ipsilateral motor cortex is believed to play a role in skilled motor control, but little is known about how training influences reorganization of ipsilateral motor representations of the trained limb. To determine whether training results in reorganization of ipsilateral motor cortex maps, rats were trained to perform the isometric pull task, an automated motor task that requires skilled forelimb use. After either 3 or 6 months of training, intracortical microstimulation (ICMS) mapping was performed to document motor representations of the trained forelimb in the hemisphere ipsilateral to that limb. Motor training for 3 months resulted in a robust expansion of right forelimb representation in the right motor cortex, demonstrating that skilled motor training drives map plasticity ipsilateral to the trained limb. After 6 months of training, the right forelimb representation in the right motor cortex was significantly smaller than the representation observed in rats trained for 3 months and similar to untrained controls, consistent with a normalization of motor cortex maps. Forelimb map area was not correlated with performance on the trained task, suggesting that task performance is maintained despite normalization of cortical maps. This study provides new insights into how the ipsilateral cortex changes in response to skilled learning and may inform rehabilitative strategies to enhance cortical plasticity to support recovery after brain injury. PMID:27392641

  17. Local production of astrocytes in the cerebral cortex.

    Science.gov (United States)

    Ge, W-P; Jia, J-M

    2016-05-26

    Astrocytes are the largest glial population in the mammalian brain. Astrocytes in the cerebral cortex are reportedly generated from four sources, namely radial glia, progenitors in the subventricular zone (SVZ progenitors), locally proliferating glia, and NG2 glia; it remains an open question, however, as to what extent these four cell types contribute to the substantial increase in astrocytes that occurs postnatally in the cerebral cortex. Here we summarize all possible sources of astrocytes and discuss their roles in this postnatal increase. In particular, we focus on astrocytes derived from local proliferation within the cortex. PMID:26343293

  18. Parietal cortex and representation of the mental Self

    DEFF Research Database (Denmark)

    Lou, Hans C; Luber, Bruce; Crupain, Michael;

    2004-01-01

    Oneself, Best Friend, and the Danish Queen, activation increased in the left lateral temporal cortex and decreased in the right inferior parietal region with decreasing self-reference. Functionally, the former region was preferentially connected to medial prefrontal cortex, the latter to medial parietal....... The medial parietal region may, then, be conceived of as a nodal structure in self-representation, functionally connected to both the right parietal and the medial prefrontal cortices. To determine whether medial parietal cortex in this network is essential for episodic memory retrieval with self...

  19. The prefrontal cortex shows context-specific changes in effective connectivity to motor or visual cortex during the selection of action or colour

    DEFF Research Database (Denmark)

    Rowe, James B.; Stephan, Klaas E.; Friston, Karl;

    2005-01-01

    used functional magnetic imaging (fMRI) to study the free selection of actions and colours. Control conditions used externally specified actions and colours. The prefrontal cortex was activated during free selection, regardless of modality, in contrast to modality-specific activations outside...... prefrontal cortex. Structural equation modelling (SEM) of fMRI data was used to test the hypothesis that although the same regions of prefrontal cortex may be active in tasks within different domains, there is task-dependent effective connectivity between prefrontal cortex and non-prefrontal cortex. The SEM...... included high-order interactions between modality, selection and regional activity. There was greater coupling between prefrontal cortex and motor cortex during free selection and action tasks, and between prefrontal cortex and visual cortex during free selection of colours. The results suggest that the...

  20. Concentric scheme of monkey auditory cortex

    Science.gov (United States)

    Kosaki, Hiroko; Saunders, Richard C.; Mishkin, Mortimer

    2003-04-01

    The cytoarchitecture of the rhesus monkey's auditory cortex was examined using immunocytochemical staining with parvalbumin, calbindin-D28K, and SMI32, as well as staining for cytochrome oxidase (CO). The results suggest that Kaas and Hackett's scheme of the auditory cortices can be extended to include five concentric rings surrounding an inner core. The inner core, containing areas A1 and R, is the most densely stained with parvalbumin and CO and can be separated on the basis of laminar patterns of SMI32 staining into lateral and medial subdivisions. From the inner core to the fifth (outermost) ring, parvalbumin staining gradually decreases and calbindin staining gradually increases. The first ring corresponds to Kaas and Hackett's auditory belt, and the second, to their parabelt. SMI32 staining revealed a clear border between these two. Rings 2 through 5 extend laterally into the dorsal bank of the superior temporal sulcus. The results also suggest that the rostral tip of the outermost ring adjoins the rostroventral part of the insula (area Pro) and the temporal pole, while the caudal tip adjoins the ventral part of area 7a.

  1. Lateralization of auditory-cortex functions.

    Science.gov (United States)

    Tervaniemi, Mari; Hugdahl, Kenneth

    2003-12-01

    In the present review, we summarize the most recent findings and current views about the structural and functional basis of human brain lateralization in the auditory modality. Main emphasis is given to hemodynamic and electromagnetic data of healthy adult participants with regard to music- vs. speech-sound encoding. Moreover, a selective set of behavioral dichotic-listening (DL) results and clinical findings (e.g., schizophrenia, dyslexia) are included. It is shown that human brain has a strong predisposition to process speech sounds in the left and music sounds in the right auditory cortex in the temporal lobe. Up to great extent, an auditory area located at the posterior end of the temporal lobe (called planum temporale [PT]) underlies this functional asymmetry. However, the predisposition is not bound to informational sound content but to rapid temporal information more common in speech than in music sounds. Finally, we obtain evidence for the vulnerability of the functional specialization of sound processing. These altered forms of lateralization may be caused by top-down and bottom-up effects inter- and intraindividually In other words, relatively small changes in acoustic sound features or in their familiarity may modify the degree in which the left vs. right auditory areas contribute to sound encoding. PMID:14629926

  2. Does the orbitofrontal cortex signal value?

    Science.gov (United States)

    Schoenbaum, Geoffrey; Takahashi, Yuji; Liu, Tzu-Lan; McDannald, Michael A

    2011-12-01

    The orbitofrontal cortex (OFC) has long been implicated in associative learning. Early work by Mishkin and Rolls showed that the OFC was critical for rapid changes in learned behavior, a role that was reflected in the encoding of associative information by orbitofrontal neurons. Over the years, new data-particularly neurophysiological data-have increasingly emphasized the OFC in signaling actual value. These signals have been reported to vary according to internal preferences and judgments and to even be completely independent of the sensory qualities of predictive cues, the actual rewards, and the responses required to obtain them. At the same time, increasingly sophisticated behavioral studies have shown that the OFC is often unnecessary for simple value-based behavior and instead seems critical when information about specific outcomes must be used to guide behavior and learning. Here, we review these data and suggest a theory that potentially reconciles these two ideas, value versus specific outcomes, and bodies of work on the OFC. PMID:22145878

  3. Inhibition in the Human Auditory Cortex.

    Directory of Open Access Journals (Sweden)

    Koji Inui

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

  4. 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...

  5. Effects of entorhinal cortex lesions on memory in different tasks

    Directory of Open Access Journals (Sweden)

    G.P. Gutierrez-Figueroa

    1997-06-01

    Full Text Available Lesions of the entorhinal cortex produce retrograde memory impairment in both animals and humans. Here we report the effects of bilateral entorhinal cortex lesions caused by the stereotaxic infusion of N-methyl-D-aspartate (NMDA in rats at two different moments, before or after the training session, on memory of different tasks: two-way shuttle avoidance, inhibitory avoidance and habituation to an open field. Pre- or post-training entorhinal cortex lesions caused an impairment of performance in the shuttle avoidance task, which agrees with the previously described role of this area in the processing of memories acquired in successive sessions. In the inhibitory avoidance task, only the post-training lesions had an effect (amnesia. No effect was observed on the open field task. The findings suggest that the role of the entorhinal cortex in memory processing is task-dependent, perhaps related to the complexity of each task

  6. Altered functional connectivity of prefrontal cortex in chronic heroin abusers

    Institute of Scientific and Technical Information of China (English)

    Yinbao Qi; Xianming Fu; Ruobing Qian; Chaoshi Niu; Xiangpin Wei

    2011-01-01

    In this study, we investigated alterations in the resting-state functional connectivity of the pre-frontal cortex in chronic heroin abusers using functional magnetic resonance imaging. We found that, compared with normal controls, in heroin abusers the left prefrontal cortex showed decreased functional connectivity with the left hippocampus, right anterior cingulate, left middle frontal gyrus, right middle frontal gyrus and right precuneus. However, the right prefrontal cortex showed decreased functional connectivity with the left orbital frontal cortex and the left middle frontal gyrus in chronic heroin abusers. These alterations of resting-state functional connectivity in the prefrontal cortices of heroin abusers suggest that their frontal executive neural network may be impaired, and that this may contribute to their continued heroin abuse and relapse after withdrawal.

  7. Human primary visual cortex topography imaged via positron tomography

    International Nuclear Information System (INIS)

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

  8. Reorganization of the Human Somatosensory Cortex in Hand Dystonia

    Directory of Open Access Journals (Sweden)

    Maria Jose Catalan

    2012-05-01

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

  9. Cortex Matures Faster in Youths With Highest IQ

    Science.gov (United States)

    ... NIH Cortex Matures Faster in Youths With Highest IQ Past Issues / Summer 2006 Table of Contents For ... on. Photo: Getty image (StockDisc) Youths with superior IQ are distinguished by how fast the thinking part ...

  10. Changing microcircuits in the subplate of the developing cortex

    OpenAIRE

    Viswanathan, Sarada; Bandyopadhyay, Sharba; Kao, Joseph P.Y.; Kanold, Patrick O.

    2012-01-01

    Subplate neurons (SPNs) are a population of neurons in the mammalian cerebral cortex that exist predominantly in the prenatal and early postnatal period. Loss of SPNs prevents the functional maturation of the cerebral cortex. SPNs receive subcortical input from the thalamus and relay this information to the developing cortical plate and thereby can influence cortical activity in a feed-forward manner. Little is known about potential feedback projections from the cortical plate to SPNs. Thus, ...

  11. Laminar circuit organization and response modulation in mouse visual cortex

    OpenAIRE

    Victor Quintanar-Zilinskas; Xiangmin Xu

    2012-01-01

    The mouse has become an increasingly important animal model for visual system studies, but few studies have investigated local functional circuit organization of mouse visual cortex. Here we used our newly developed mapping technique combining laser scanning photostimulation (LSPS) with fast voltage-sensitive dye (VSD) imaging to examine the spatial organization and temporal dynamics of laminar circuit responses in living slice preparations of mouse primary visual cortex (V1). During experi...

  12. Auditory Cortex Basal Activity Modulates Cochlear Responses in Chinchillas

    OpenAIRE

    León, Alex; Elgueda, Diego; Silva, María A.; Hamamé, Carlos M.; Delano, Paul H.

    2012-01-01

    Background The auditory efferent system has unique neuroanatomical pathways that connect the cerebral cortex with sensory receptor cells. Pyramidal neurons located in layers V and VI of the primary auditory cortex constitute descending projections to the thalamus, inferior colliculus, and even directly to the superior olivary complex and to the cochlear nucleus. Efferent pathways are connected to the cochlear receptor by the olivocochlear system, which innervates outer hair cells and auditory...

  13. Mapping the structural core of human cerebral cortex.

    OpenAIRE

    Hagmann, Patric; Cammoun, Leila; Gigandet, Xavier; Meuli, Reto; Honey, Christopher J.; Sporns, Olaf; Wedeen, Van Jay

    2008-01-01

    Author Summary In the human brain, neural activation patterns are shaped by the underlying structural connections that form a dense network of fiber pathways linking all regions of the cerebral cortex. Using diffusion imaging techniques, which allow the noninvasive mapping of fiber pathways, we constructed connection maps covering the entire cortical surface. Computational analyses of the resulting complex brain network reveal regions of cortex that are highly connected and highly central, fo...

  14. Connectivity Changes Underlying Neurofeedback Training of Visual Cortex Activity

    OpenAIRE

    Frank Scharnowski; Maria Joao Rosa; Narly Golestani; Chloe Hutton; Oliver Josephs; Nikolaus Weiskopf; Geraint Rees

    2014-01-01

    Neurofeedback based on real-time functional magnetic resonance imaging (fMRI) is a new approach that allows training of voluntary control over regionally specific brain activity. However, the neural basis of successful neurofeedback learning remains poorly understood. Here, we assessed changes in effective brain connectivity associated with neurofeedback training of visual cortex activity. Using dynamic causal modeling (DCM), we found that training participants to increase visual cortex activ...

  15. Molecular mechanisms of experience-dependent plasticity in visual cortex

    OpenAIRE

    Tropea, Daniela; Van Wart, Audra; Sur, Mriganka

    2008-01-01

    A remarkable amount of our current knowledge of mechanisms underlying experience-dependent plasticity during cortical development comes from study of the mammalian visual cortex. Recent advances in high-resolution cellular imaging, combined with genetic manipulations in mice, novel fluorescent recombinant probes, and large-scale screens of gene expression, have revealed multiple molecular mechanisms that underlie structural and functional plasticity in visual cortex. We situate these mechanis...

  16. Occurrence of new neurons in the piriform cortex

    Directory of Open Access Journals (Sweden)

    Ti-Fei eYuan

    2015-01-01

    Full Text Available Adult neurogenesis has been well studied in hippocampus and subventricular zone; while this is much less appreciated in other brain regions, including amygdala, hypothalamus and piriform cortex. The present review aims at summarizing recent advances on the occurrence of new neurons in the piriform cortex, their potential origin and migration route from the subventricular zone. We further discuss the relevant implications in olfactory dysfunction accompanying the neuro-degenerative diseases.

  17. Medial cortex activity, self-reflection and depression

    OpenAIRE

    Johnson, Marcia K.; Nolen-Hoeksema, Susan; Mitchell, Karen J.; Levin, Yael

    2009-01-01

    Using functional magnetic resonance imaging, we investigated neural activity associated with self-reflection in depressed [current major depressive episode (MDE)] and healthy control participants, focusing on medial cortex areas previously shown to be associated with self-reflection. Both the MDE and healthy control groups showed greater activity in anterior medial cortex (medial frontal gyrus, anterior cingulate gyrus) when cued to think about hopes and aspirations compared with duties and o...

  18. Specialized cortical subnetworks differentially connect frontal cortex to parahippocampal areas.

    Science.gov (United States)

    Hirai, Yasuharu; Morishima, Mieko; Karube, Fuyuki; Kawaguchi, Yasuo

    2012-02-01

    How information is manipulated and segregated within local circuits in the frontal cortex remains mysterious, in part because of inadequate knowledge regarding the connectivity of diverse pyramidal cell subtypes. The frontal cortex participates in the formation and retrieval of declarative memories through projections to the perirhinal cortex, and in procedural learning through projections to the striatum/pontine nuclei. In rat frontal cortex, we identified two pyramidal cell subtypes selectively projecting to distinct subregions of perirhinal cortex (PRC). PRC-projecting cells in upper layer 2/3 (L2/3) of the frontal cortex projected to perirhinal area 35, while neurons in L5 innervated perirhinal area 36. L2/3 PRC-projecting cells partially overlapped with those projecting to the basolateral amygdala. L5 PRC-projecting cells partially overlapped with crossed corticostriatal cells, but were distinct from neighboring corticothalamic (CTh)/corticopontine cells. L5 PRC-projecting and CTh cells were different in their electrophysiological properties and dendritic/axonal morphologies. Within the frontal cortex, L2/3 PRC-projecting cells innervated L5 PRC-projecting and CTh cells with similar probabilities, but received feedback excitation only from PRC-projecting cells. These data suggest that specific neuron subtypes in different cortical layers are reciprocally excited via interlaminar loops. Thus, two interacting output channels send information from the frontal cortex to different hierarchical stages of the parahippocampal network, areas 35 and 36, with additional collaterals selectively targeting the amygdala or basal ganglia, respectively. Combined with the hierarchical connectivity of PRC-projecting and CTh cells, these observations demonstrate an exquisite diversification of frontal projection neurons selectively connected according to their participation in distinct memory subsystems. PMID:22302828

  19. Effects of healthy aging on human primary visual cortex

    OpenAIRE

    2012-01-01

    Aging often results in reduced visual acuity from changes in both the eye and neural circuits [1-4]. In normally aging subjects, primary visual cortex has been shown to have reduced responses to visual stimulation [5]. It is not known, however, to what extent aging affects visual field representations and population receptive sizes in human primary visual cortex. Here we use functional MRI (fMRI) and population receptive field (pRF) modeling [6] to measure angular and eccentric retinotopic re...

  20. A disinhibitory microcircuit initiates critical period plasticity in visual cortex

    OpenAIRE

    Kuhlman, Sandra J.; Olivas, Nicholas D.; Tring, Elaine; Ikrar, Taruna; Xu, Xiangmin; Trachtenberg, Joshua T.

    2013-01-01

    Early sensory experience instructs the maturation of neural circuitry in cortex 1,2 . This has been extensively studied in the primary visual cortex where loss of vision to one eye permanently degrades cortical responsiveness to that eye 3,4 , a phenomenon known as ocular dominance plasticity (ODP). Cortical inhibition mediates this process 4-6 , but the precise role of specific classes of inhibitory neurons in ODP is controversial. Here we report that evoked firing rates of binocular excitat...

  1. Audiovisual Association Learning in the Absence of Primary Visual Cortex

    OpenAIRE

    Seirafi, Mehrdad; De Weerd, Peter; Pegna, Alan J.; de Gelder, Beatrice

    2016-01-01

    Learning audiovisual associations is mediated by the primary cortical areas; however, recent animal studies suggest that such learning can take place even in the absence of the primary visual cortex. Other studies have demonstrated the involvement of extra-geniculate pathways and especially the superior colliculus (SC) in audiovisual association learning. Here, we investigated such learning in a rare human patient with complete loss of the bilateral striate cortex. We carried out an implicit ...

  2. Functional reorganization of sensorimotor cortex in early Parkinson disease.

    OpenAIRE

    Kojovic, M.; Bologna, M; Kassavetis, P.; Murase, N.; Palomar, F. J.; Berardelli, A; Rothwell, J C; Edwards, M. J.; Bhatia, K P

    2012-01-01

    OBJECTIVE: Compensatory reorganization of the nigrostriatal system is thought to delay the onset of symptoms in early Parkinson disease (PD). Here we sought evidence that compensation may be a part of a more widespread functional reorganization in sensorimotor networks, including primary motor cortex. METHODS: Several neurophysiologic measures known to be abnormal in the motor cortex (M1) of patients with advanced PD were tested on the more and less affected side of 16 newly diagnosed and dru...

  3. High membrane protein oxidation in the human cerebral cortex

    OpenAIRE

    Matthias Granold; Bernd Moosmann; Irina Staib-Lasarzik; Thomas Arendt; Adriana del Rey; Kristin Engelhard; Christian Behl; Parvana Hajieva

    2014-01-01

    Oxidative stress is thought to be one of the main mediators of neuronal damage in human neurodegenerative disease. Still, the dissection of causal relationships has turned out to be remarkably difficult. Here, we have analyzed global protein oxidation in terms of carbonylation of membrane proteins and cytoplasmic proteins in three different mammalian species: aged human cortex and cerebellum from patients with or without Alzheimer's disease, mouse cortex and cerebellum from young and old anim...

  4. Specialized Pathways from the Primate Amygdala to Posterior Orbitofrontal Cortex

    OpenAIRE

    Timbie, Clare; Barbas, Helen

    2014-01-01

    The primate amygdala sends dense projections to posterior orbitofrontal cortex (pOFC) in pathways that are critical for processing emotional content, but the synaptic mechanisms are not understood. We addressed this issue by investigating pathways in rhesus monkeys (Macaca mulatta) from the amygdala to pOFC at the level of the system and synapse. Terminations from the amygdala were denser and larger in pOFC compared with the anterior cingulate cortex, which is also strongly connected with the...

  5. The multisensory function of the human primary visual cortex.

    Science.gov (United States)

    Murray, Micah M; Thelen, Antonia; Thut, Gregor; Romei, Vincenzo; Martuzzi, Roberto; Matusz, Pawel J

    2016-03-01

    It has been nearly 10 years since Ghazanfar and Schroeder (2006) proposed that the neocortex is essentially multisensory in nature. However, it is only recently that sufficient and hard evidence that supports this proposal has accrued. We review evidence that activity within the human primary visual cortex plays an active role in multisensory processes and directly impacts behavioural outcome. This evidence emerges from a full pallet of human brain imaging and brain mapping methods with which multisensory processes are quantitatively assessed by taking advantage of particular strengths of each technique as well as advances in signal analyses. Several general conclusions about multisensory processes in primary visual cortex of humans are supported relatively solidly. First, haemodynamic methods (fMRI/PET) show that there is both convergence and integration occurring within primary visual cortex. Second, primary visual cortex is involved in multisensory processes during early post-stimulus stages (as revealed by EEG/ERP/ERFs as well as TMS). Third, multisensory effects in primary visual cortex directly impact behaviour and perception, as revealed by correlational (EEG/ERPs/ERFs) as well as more causal measures (TMS/tACS). While the provocative claim of Ghazanfar and Schroeder (2006) that the whole of neocortex is multisensory in function has yet to be demonstrated, this can now be considered established in the case of the human primary visual cortex. PMID:26275965

  6. Spatial processing in the auditory cortex of the macaque monkey

    Science.gov (United States)

    Recanzone, Gregg H.

    2000-10-01

    The patterns of cortico-cortical and cortico-thalamic connections of auditory cortical areas in the rhesus monkey have led to the hypothesis that acoustic information is processed in series and in parallel in the primate auditory cortex. Recent physiological experiments in the behaving monkey indicate that the response properties of neurons in different cortical areas are both functionally distinct from each other, which is indicative of parallel processing, and functionally similar to each other, which is indicative of serial processing. Thus, auditory cortical processing may be similar to the serial and parallel "what" and "where" processing by the primate visual cortex. If "where" information is serially processed in the primate auditory cortex, neurons in cortical areas along this pathway should have progressively better spatial tuning properties. This prediction is supported by recent experiments that have shown that neurons in the caudomedial field have better spatial tuning properties than neurons in the primary auditory cortex. Neurons in the caudomedial field are also better than primary auditory cortex neurons at predicting the sound localization ability across different stimulus frequencies and bandwidths in both azimuth and elevation. These data support the hypothesis that the primate auditory cortex processes acoustic information in a serial and parallel manner and suggest that this may be a general cortical mechanism for sensory perception.

  7. Medial cortex activity, self-reflection and depression.

    Science.gov (United States)

    Johnson, Marcia K; Nolen-Hoeksema, Susan; Mitchell, Karen J; Levin, Yael

    2009-12-01

    Using functional magnetic resonance imaging, we investigated neural activity associated with self-reflection in depressed [current major depressive episode (MDE)] and healthy control participants, focusing on medial cortex areas previously shown to be associated with self-reflection. Both the MDE and healthy control groups showed greater activity in anterior medial cortex (medial frontal gyrus, anterior cingulate gyrus) when cued to think about hopes and aspirations compared with duties and obligations, and greater activity in posterior medial cortex (precuneus, posterior cingulate) when cued to think about duties and obligations (Experiment 1). However, the MDE group showed less activity than controls in the same area of medial frontal cortex when self-referential cues were more ambiguous with respect to valence (Experiment 2), and less deactivation in a non-self-referential condition in both experiments. Furthermore, individual differences in rumination were positively correlated with activity in both anterior and posterior medial cortex during non-self-referential conditions. These results provide converging evidence for a dissociation of anterior and posterior medial cortex depending on the focus of self-relevant thought. They also provide neural evidence consistent with behavioral findings that depression is associated with disruption of positively valenced thoughts in response to ambiguous cues, and difficulty disengaging from self-reflection when it is appropriate to do so. PMID:19620180

  8. What does spatial alternation tell us about retrosplenial cortex function?

    Directory of Open Access Journals (Sweden)

    Andrew John Dudley Nelson

    2015-05-01

    Full Text Available The retrosplenial cortex supports navigation, but there are good reasons to suppose that the retrosplenial cortex has a very different role in spatial memory from that of the hippocampus and anterior thalamic nuclei. For example, retrosplenial lesions appear to have little or no effect on standard tests of spatial alternation. To examine these differences, the current study sought to determine whether the retrosplenial cortex is important for just one spatial cue type (e.g. allocentric, directional or intra-maze cues or whether the retrosplenial cortex helps the animal switch between competing spatial strategies or competing cue types. Using T-maze alternation, retrosplenial lesion rats were challenged with situations in which the available spatial information between the sample and test phases was changed, so taxing the interaction between different cue types. Clear lesion deficits emerged when intra- and extra-maze cues were placed in conflict (by rotating the maze between the sample and choice phases, or when the animals were tested in the dark in a double-maze. Finally, temporary inactivation of the retrosplenial cortex by muscimol infusions resulted in a striking deficit on standard T-maze alternation, indicating that, over time, other sites may be able to compensate for the loss of the retrosplenial cortex. This pattern of results is consistent with the impoverished use of both allocentric and directional information, exacerbated by an impaired ability to switch between different cue types.

  9. Tinnitus intensity dependent gamma oscillations of the contralateral auditory cortex.

    Directory of Open Access Journals (Sweden)

    Elsa van der Loo

    Full Text Available BACKGROUND: Non-pulsatile tinnitus is considered a subjective auditory phantom phenomenon present in 10 to 15% of the population. Tinnitus as a phantom phenomenon is related to hyperactivity and reorganization of the auditory cortex. Magnetoencephalography studies demonstrate a correlation between gamma band activity in the contralateral auditory cortex and the presence of tinnitus. The present study aims to investigate the relation between objective gamma-band activity in the contralateral auditory cortex and subjective tinnitus loudness scores. METHODS AND FINDINGS: In unilateral tinnitus patients (N = 15; 10 right, 5 left source analysis of resting state electroencephalographic gamma band oscillations shows a strong positive correlation with Visual Analogue Scale loudness scores in the contralateral auditory cortex (max r = 0.73, p<0.05. CONCLUSION: Auditory phantom percepts thus show similar sound level dependent activation of the contralateral auditory cortex as observed in normal audition. In view of recent consciousness models and tinnitus network models these results suggest tinnitus loudness is coded by gamma band activity in the contralateral auditory cortex but might not, by itself, be responsible for tinnitus perception.

  10. High membrane protein oxidation in the human cerebral cortex

    Directory of Open Access Journals (Sweden)

    Matthias Granold

    2015-04-01

    Full Text Available Oxidative stress is thought to be one of the main mediators of neuronal damage in human neurodegenerative disease. Still, the dissection of causal relationships has turned out to be remarkably difficult. Here, we have analyzed global protein oxidation in terms of carbonylation of membrane proteins and cytoplasmic proteins in three different mammalian species: aged human cortex and cerebellum from patients with or without Alzheimer's disease, mouse cortex and cerebellum from young and old animals, and adult rat hippocampus and cortex subjected or not subjected to cerebral ischemia. Most tissues showed relatively similar levels of protein oxidation. However, human cortex was affected by severe membrane protein oxidation, while exhibiting lower than average cytoplasmic protein oxidation. In contrast, ex vivo autooxidation of murine cortical tissue primarily induced aqueous protein oxidation, while in vivo biological aging or cerebral ischemia had no major effect on brain protein oxidation. The unusually high levels of membrane protein oxidation in the human cortex were also not predicted by lipid peroxidation, as the levels of isoprostane immunoreactivity in human samples were considerably lower than in rodent tissues. Our results indicate that the aged human cortex is under steady pressure from specific and potentially detrimental membrane protein oxidation. The pronounced difference between humans, mice and rats regarding the primary site of cortical oxidation might have contributed to the unresolved difficulties in translating into therapies the wealth of data describing successful antioxidant neuroprotection in rodents.

  11. Evidence of residual disease in cryopreserved ovarian cortex from female patients with leukemia

    DEFF Research Database (Denmark)

    Rosendahl, Mikkel; Andersen, Morten Tolstrup; Ralfkiær, Elisabeth; Kjeldsen, Lars; Andersen, Mette Klarskov; Andersen, Claus Yding

    2010-01-01

    To systematically search for leukemic cells in cryopreserved ovarian cortex from Danish female patients with leukemia, who had ovarian cortex cryopreserved for fertility preservation before potentially sterilizing treatment.......To systematically search for leukemic cells in cryopreserved ovarian cortex from Danish female patients with leukemia, who had ovarian cortex cryopreserved for fertility preservation before potentially sterilizing treatment....

  12. Preferential encoding of visual categories in parietal cortex compared with prefrontal cortex.

    Science.gov (United States)

    Swaminathan, Sruthi K; Freedman, David J

    2012-02-01

    The ability to recognize the behavioral relevance, or category membership, of sensory stimuli is critical for interpreting the meaning of events in our environment. Neurophysiological studies of visual categorization have found categorical representations of stimuli in prefrontal cortex (PFC), an area that is closely associated with cognitive and executive functions. Recent studies have also identified neuronal category signals in parietal areas that are typically associated with visual-spatial processing. It has been proposed that category-related signals in parietal cortex and other visual areas may result from 'top-down' feedback from PFC. We directly compared neuronal activity in the lateral intraparietal (LIP) area and PFC in monkeys performing a visual motion categorization task. We found that LIP showed stronger, more reliable and shorter latency category signals than PFC. These findings suggest that LIP is strongly involved in visual categorization and argue against the idea that parietal category signals arise as a result of feedback from PFC during this task. PMID:22246435

  13. Epileptiform synchronization in the cingulate cortex

    Science.gov (United States)

    Panuccio, Gabriella; Curia, Giulia; Colosimo, Alfredo; Cruccu, Giorgio; Avoli, Massimo

    2016-01-01

    Summary Purpose The anterior cingulate cortex (ACC)— which plays a role in pain, emotions and behavior— can generate epileptic seizures. To date, little is known on the neuronal mechanisms leading to epileptiform synchronization in this structure. Therefore, we investigated the role of excitatory and inhibitory synaptic transmission in epileptiform activity in this cortical area. In addition, since the ACC presents with a high density of opioid receptors, we studied the effect of opioid agonism on epileptiform synchronization in this brain region. Methods We used field and intracellular recordings in conjunction with pharmacological manipulations to characterize the epileptiform activity generated by the rat ACC in a brain slice preparation. Results Bath-application of the convulsant 4- aminopyridine (4AP, 50 μM) induced both brief and prolonged periods of epileptiform synchronization resembling interictal- and ictal-like discharges, respectively. Interictal events could occur more frequently before the onset of ictal activity that was contributed by N-methyl-D-aspartate (NMDA) receptors. Mu-opioid receptor activation abolished 4AP-induced ictal events and markedly reduced the occurrence of the pharmacologically isolated GABAergic synchronous potentials. Ictal discharges were replaced by interictal events during GABAergic antagonism; this GABA-independent activity was influenced by subsequent mu-opioid agonist application. Conclusions Our results indicate that both glutamatergic and GABAergic signaling contribute to epileptiform synchronization leading to the generation of electrographic ictal events in the ACC. In addition, mu-opioid receptors appear to modulate both excitatory and inhibitory mechanisms, thus influencing epileptiform synchronization in the ACC. PMID:19178556

  14. The Basal Forebrain and Motor Cortex Provide Convergent yet Distinct Movement-Related Inputs to the Auditory Cortex.

    Science.gov (United States)

    Nelson, Anders; Mooney, Richard

    2016-05-01

    Cholinergic inputs to the auditory cortex from the basal forebrain (BF) are important to auditory processing and plasticity, but little is known about the organization of these synapses onto different auditory cortical neuron types, how they influence auditory responsiveness, and their activity patterns during various behaviors. Using intersectional tracing, optogenetic circuit mapping, and in vivo calcium imaging, we found that cholinergic axons arising from the caudal BF target major excitatory and inhibitory auditory cortical cell types, rapidly modulate auditory cortical tuning, and display fast movement-related activity. Furthermore, the BF and the motor cortex-another source of movement-related activity-provide convergent input onto some of the same auditory cortical neurons. Cholinergic and motor cortical afferents to the auditory cortex display distinct activity patterns and presynaptic partners, indicating that the auditory cortex integrates bottom-up cholinergic signals related to ongoing movements and arousal with top-down information concerning impending movements and motor planning. PMID:27112494

  15. The effects of prefrontal cortex inactivation on object responses of single neurons in the inferotemporal cortex during visual search

    OpenAIRE

    Monosov, Ilya E.; David L Sheinberg; Thompson, Kirk G.

    2011-01-01

    Inferotemporal cortex (IT) is believed to be directly involved in object processing and necessary for accurate and efficient object recognition. The frontal eye field (FEF) is an area in the primate prefrontal cortex that is involved in visual spatial selection and is thought to guide spatial attention and eye movements. We show that object selective responses of IT neurons and behavioral performance are affected by changes in frontal eye field activity. This was found in monkeys performing a...

  16. Cortico-cortical connections of the motor cortex in the brushtailed possum (Trichosurus vulpecula).

    OpenAIRE

    Joschko, M A; Sanderson, K J

    1987-01-01

    Cortico-cortical connections of motor cortex in the marsupial brushtailed possum were traced by making injections of horseradish peroxidase (HRP) into two parts of motor cortex: the rostral agranular part which does not overlap somatosensory cortex, and the caudal part which does. Following injections in motor cortex, labelled neurons were observed on the same side of the brain within somatosensory areas 1 and 2 and in parietal cortex just caudal to S1, with most neurons in cortical Layers 2-...

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

    OpenAIRE

    Potgieser, Adriaan Remco Ewoud

    2015-01-01

    The premotor cortex is a brain structure that is involved in the preparation of movements. It has an important role in the final integration of task-related information and to funnel this to the primary motor cortex, which subsequently causes the execution of a movement. Premotor areas can also influence motor output through their direct interactions with both the spinal cord. Within the premotor cortex, the ventral premotor cortex (PMv), dorsal premotor cortex (PMd) and supplementary motor a...

  18. Cultivating the cortex in German neuroanatomy.

    Science.gov (United States)

    Hagner, M

    2001-12-01

    The cerebral localization of mental functions is one of the centerpieces of modern brain research. Though the localization paradigm in its cultural and social interwovenness has been characterized as successful in the last third of the nineteenth century by a variety of historians of the neurosciences, there is also general agreement that localization came under threat around 1900. Besides the so-called holistic protest against the localization of mental functions, the neuroanatomical approach itself was challenged by experimental psychology, psychiatric nosology, and psychoanalysis. This story underestimates the fact that anatomically-based localization remained powerful in response to these multiple challenges. This meant a neuroanatomical revision of tools, concepts, and practices. But this meant also a shift in the cultivation of the cortex from a more philosophical agenda to rather concrete political claims. More specifically, the idea of the cortext as the noblest part of man was supplemented by suggestions concerning its "Höherzüchtung." I will analyze this re-orientation and radicalization in two steps. First, I briefly discuss the anatomical and philosophical account of Theodor Meynert and then turn to Paul Flechsig who in the late nineteenth century inscribed the ability to create culture and civilization into the cortext. Second, I focus on the neuroanatomists Oskar and Cécile Vogt, who began their careers around 1900 and expanded the cultivation of the cortext. Even before World War I, they proclaimed a "cerebral hygiene." Consequently, the Vogts linked their innovative neuroanatomical researches with the rising field of genetics, racial hygiene, and eugenics. In the early Weimar Republic, the Vogts openly supported socialist ideas and were engaged in establishing an Institute for Brain Research in Soviet Moscow, where Lenin's brain was analyzed. By the end of the Weimar Republic, the rhetoric of the Vogts was bluntly authoritarian. Based on a few

  19. Changes in Cerebral Cortex of Children Treated for Medulloblastoma

    International Nuclear Information System (INIS)

    Purpose: Children with medulloblastoma undergo surgery, radiotherapy, and chemotherapy. After treatment, these children have numerous structural abnormalities. Using high-resolution magnetic resonance imaging, we measured the thickness of the cerebral cortex in a group of medulloblastoma patients and a group of normally developing children. Methods and Materials: We obtained magnetic resonance imaging scans and measured the cortical thickness in 9 children after treatment of medulloblastoma. The measurements from these children were compared with the measurements from age- and gender-matched normally developing children previously scanned. For additional comparison, the pattern of thickness change was compared with the cortical thickness maps from a larger group of 65 normally developing children. Results: In the left hemisphere, relatively thinner cortex was found in the perirolandic region and the parieto-occipital lobe. In the right hemisphere, relatively thinner cortex was found in the parietal lobe, posterior superior temporal gyrus, and lateral temporal lobe. These regions of cortical thinning overlapped with the regions of cortex that undergo normal age-related thinning. Conclusion: The spatial distribution of cortical thinning suggested that the areas of cortex that are undergoing development are more sensitive to the effects of treatment of medulloblastoma. Such quantitative methods may improve our understanding of the biologic effects that treatment has on the cerebral development and their neuropsychological implications

  20. 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.

  1. The orbitofrontal cortex: novelty, deviation from expectation, and memory.

    Science.gov (United States)

    Petrides, Michael

    2007-12-01

    The orbitofrontal cortex is strongly connected with limbic areas of the medial temporal lobe that are critically involved in the establishment of declarative memories (entorhinal and perirhinal cortex and the hippocampal region) as well as the amygdala and the hypothalamus that are involved in emotional and motivational states. The present article reviews evidence regarding the role of the orbitofrontal cortex in the processing of novel information, breaches of expectation, and memory. Functional neuroimaging evidence is provided that there is a difference between the anterior and posterior orbitofrontal cortex in such processing. Exposure to novel information gives rise to a selective increase of activity in the granular anterior part of the orbitofrontal cortex (area 11) and this activity increases when subjects attempt to encode this information in memory. If the stimuli violate expectations (e.g., inspection of graffiti-like stimuli in the context of other regular stimuli) or are unpleasant (i.e., exposure to the sounds of car crashes), there is increased response in the posteromedial agranular/dysgranular area 13 of the orbitofrontal region. The anatomic data provide a framework within which to understand these functional neuroimaging findings. PMID:17872393

  2. Responses of primate frontal cortex neurons during natural vocal communication.

    Science.gov (United States)

    Miller, Cory T; Thomas, A Wren; Nummela, Samuel U; de la Mothe, Lisa A

    2015-08-01

    The role of primate frontal cortex in vocal communication and its significance in language evolution have a controversial history. While evidence indicates that vocalization processing occurs in ventrolateral prefrontal cortex neurons, vocal-motor activity has been conjectured to be primarily subcortical and suggestive of a distinctly different neural architecture from humans. Direct evidence of neural activity during natural vocal communication is limited, as previous studies were performed in chair-restrained animals. Here we recorded the activity of single neurons across multiple regions of prefrontal and premotor cortex while freely moving marmosets engaged in a natural vocal behavior known as antiphonal calling. Our aim was to test whether neurons in marmoset frontal cortex exhibited responses during vocal-signal processing and/or vocal-motor production in the context of active, natural communication. We observed motor-related changes in single neuron activity during vocal production, but relatively weak sensory responses for vocalization processing during this natural behavior. Vocal-motor responses occurred both prior to and during call production and were typically coupled to the timing of each vocalization pulse. Despite the relatively weak sensory responses a population classifier was able to distinguish between neural activity that occurred during presentations of vocalization stimuli that elicited an antiphonal response and those that did not. These findings are suggestive of the role that nonhuman primate frontal cortex neurons play in natural communication and provide an important foundation for more explicit tests of the functional contributions of these neocortical areas during vocal behaviors. PMID:26084912

  3. Posterior parietal cortex dynamically ranks topographic signals via cholinergic influence

    Directory of Open Access Journals (Sweden)

    John Broussard

    2012-06-01

    Full Text Available The hypothesis to be discussed in this review is that posterior parietal cortex is directly involved in selecting relevant stimuli and filtering irrelevant distractors. The posterior parietal cortex receives input from several sensory modalities and integrates them in part to direct the allocation of resources to optimize gains. In conjunction with prefrontal cortex, nucleus accumbens, and basal forebrain cholinergic nuclei, it comprises a network mediating sustained attentional performance. Numerous anatomical, neurophysiological, and lesion studies have substantiated the notion that the basic functions of the posterior parietal cortex are conserved from rodents to humans. One such function is the detection and selection of relevant stimuli necessary for making optimal choices or responses. The issues to be addressed here are how behaviorally relevant targets recruit oscillatory potentials and spiking activity of posterior parietal neurons compared to similar yet irrelevant stimuli. Further, the influence of cortical cholinergic input to posterior parietal cortex in learning and decision-making is also discussed. I propose that these neurophysiological correlates of attention are transmitted to frontal cortical areas contributing to the top down selection of stimuli in a timely manner.

  4. Can lesions to the motor cortex induce amyotrophic lateral sclerosis?

    Science.gov (United States)

    Rosenbohm, Angela; Kassubek, Jan; Weydt, Patrick; Marroquin, Nicolai; Volk, Alexander E; Kubisch, Christian; Huppertz, Hans-Jürgen; Weber, Markus; Andersen, Peter M; Weishaupt, Jochen H; Ludolph, Albert C

    2014-02-01

    A recent staging effort for amyotrophic lateral sclerosis (ALS) has demonstrated that the TDP-43 neuropathology may initiate focally in the motor cortex in the majority of patients. We searched our data bank for patients with lesions of the motor cortex which preceded disease onset. We performed a search of our patient- and MRI-data bank and screened 1,835 patients with amyotrophic lateral sclerosis for frontal lobe/motor cortex lesions. We found 18 patients with definite ALS who had documented and defined lesions of the motor cortex, which preceded the initial ALS symptoms by 8-42 years. In the vast majority (15/18) of the patients, the onset of ALS was closely related to the focal lesion since it started in a body region reflecting the damaged cortical area. The findings suggest that initial lesions to the motor cortex may be a contributing initiating factor in some patients with ALS or determine the site of onset in individuals pre-disposed to ALS. PMID:24253481

  5. Characterization of auditory synaptic inputs to gerbil perirhinal cortex

    Directory of Open Access Journals (Sweden)

    Vibhakar C Kotak

    2015-08-01

    Full Text Available The representation of acoustic cues involves regions downstream from the auditory cortex (ACx. One such area, the perirhinal cortex (PRh, processes sensory signals containing mnemonic information. Therefore, our goal was to assess whether PRh receives auditory inputs from the auditory thalamus (MG and ACx in an auditory thalamocortical brain slice preparation and characterize these afferent-driven synaptic properties. When the MG or ACx was electrically stimulated, synaptic responses were recorded from the PRh neurons. Blockade of GABA-A receptors dramatically increased the amplitude of evoked excitatory potentials. Stimulation of the MG or ACx also evoked calcium transients in most PRh neurons. Separately, when fluoro ruby was injected in ACx in vivo, anterogradely labeled axons and terminals were observed in the PRh. Collectively, these data show that the PRh integrates auditory information from the MG and ACx and that auditory driven inhibition dominates the postsynaptic responses in a non-sensory cortical region downstream from the auditory cortex.

  6. Individuals' and groups' intentions in the medial prefrontal cortex.

    Science.gov (United States)

    Chaminade, Thierry; Kawato, Mitsuo; Frith, Chris

    2011-11-16

    Functional MRI signal was recorded while participants perceived stimuli presented using moving dots. In two conditions of interest, the motion of dots depicted intentions: dots representing the joints of an agent performing an action, and dots representing individual agents behaving contingently. The finding of a common cluster in the posterior part of the medial frontal cortex involved in intentional action representation validates the hypothesis that perception of these two conditions requires a similar internal representation. A cluster responding to the behaving group only is found in the anterior medial frontal cortex. These results support a division of the medial frontal cortex according to social stimuli attributes, with anterior areas responding to higher-order group behaviours integrating the action of multiple individual agents. PMID:21897305

  7. Associative Hebbian Synaptic Plasticity in Primate Visual Cortex

    Science.gov (United States)

    Huang, Shiyong; Rozas, Carlos; Treviño, Mario; Contreras, Jessica; Yang, Sunggu; Song, Lihua; Yoshioka, Takashi; Lee, Hey-Kyoung

    2014-01-01

    In primates, the functional connectivity of adult primary visual cortex is susceptible to be modified by sensory training during perceptual learning. It is widely held that this type of neural plasticity might involve mechanisms like long-term potentiation (LTP) and long-term depression (LTD). NMDAR-dependent forms of LTP and LTD are particularly attractive because in rodents they can be induced in a Hebbian manner by near coincidental presynaptic and postsynaptic firing, in a paradigm termed spike timing-dependent plasticity (STDP). These fundamental properties of LTP and LTD, Hebbian induction and NMDAR dependence, have not been examined in primate cortex. Here we demonstrate these properties in the primary visual cortex of the rhesus macaque (Macaca mulatta), and also show that, like in rodents, STDP is gated by neuromodulators. These findings indicate that the cellular principles governing cortical plasticity are conserved across mammalian species, further validating the use of rodents as a model system. PMID:24872561

  8. Adaptation to sensory input tunes visual cortex to criticality

    Science.gov (United States)

    Shew, Woodrow L.; Clawson, Wesley P.; Pobst, Jeff; Karimipanah, Yahya; Wright, Nathaniel C.; Wessel, Ralf

    2015-08-01

    A long-standing hypothesis at the interface of physics and neuroscience is that neural networks self-organize to the critical point of a phase transition, thereby optimizing aspects of sensory information processing. This idea is partially supported by strong evidence for critical dynamics observed in the cerebral cortex, but the impact of sensory input on these dynamics is largely unknown. Thus, the foundations of this hypothesis--the self-organization process and how it manifests during strong sensory input--remain unstudied experimentally. Here we show in visual cortex and in a computational model that strong sensory input initially elicits cortical network dynamics that are not critical, but adaptive changes in the network rapidly tune the system to criticality. This conclusion is based on observations of multifaceted scaling laws predicted to occur at criticality. Our findings establish sensory adaptation as a self-organizing mechanism that maintains criticality in visual cortex during sensory information processing.

  9. Altered intrinsic connectivity of the auditory cortex in congenital amusia.

    Science.gov (United States)

    Leveque, Yohana; Fauvel, Baptiste; Groussard, Mathilde; Caclin, Anne; Albouy, Philippe; Platel, Hervé; Tillmann, Barbara

    2016-07-01

    Congenital amusia, a neurodevelopmental disorder of music perception and production, has been associated with abnormal anatomical and functional connectivity in a right frontotemporal pathway. To investigate whether spontaneous connectivity in brain networks involving the auditory cortex is altered in the amusic brain, we ran a seed-based connectivity analysis, contrasting at-rest functional MRI data of amusic and matched control participants. Our results reveal reduced frontotemporal connectivity in amusia during resting state, as well as an overconnectivity between the auditory cortex and the default mode network (DMN). The findings suggest that the auditory cortex is intrinsically more engaged toward internal processes and less available to external stimuli in amusics compared with controls. Beyond amusia, our findings provide new evidence for the link between cognitive deficits in pathology and abnormalities in the connectivity between sensory areas and the DMN at rest. PMID:27009161

  10. Visual cortex controls retinal output in the rat.

    Science.gov (United States)

    Molotchnikoff, S; Tremblay, F

    1986-07-01

    The first objective of the present investigation was to shed more light on corticofugal influences on the retina by providing an analysis of the type and proportion of retinal ganglion cells that are affected by cooling the visual cortex in rats. The second question was to determine if the pretectum participates in functional cortico-retinal relationships. In urethane-anesthetized and paralyzed hooded rats, axonal activity of retinal ganglion cells was recorded with glass micropipettes at optic chiasm level. Units were classified as ON, OFF, suppressed-by-light and concentric. The visual cortex was inactivated by cooling its surface with a 4 mm2 steel probe using the Peltier effect. The pretectum was blocked with microinjections of 50 to 100 nanoliters of cobalt ions, lidocaine hydrochloride or KCl. The inactivations and recoveries at both sites were monitored by simultaneously recording evoked field potentials. Interrupting corticofugal impulses caused modifications of the evoked discharge pattern in all types of cells. The concentric type was the group least affected by cortical cooling. A common trend emerged suggesting that cooling of the visual cortex led to an enhancement of the initial evoked excitation. This was often followed by an enhanced post-excitatory inhibition. The Pearson coefficient allowed us to measure the degree of similarity between two histograms. When all data were pooled, a weak correlation between control and test histograms (r = 0.29, N = 56) was found, while the control and recovery patterns averaged a correlation of more than twice that size (r = 0.68). In a second series of experiments, the pretectum and visual cortex (VC) were simultaneously inactivated. It is shown that both sites summed their influence and acted synergistically upon the pattern of ganglion cell responses. The results strongly suggest that the visual cortex exerts a major control over the response pattern of thirty percent of retinal ganglion cells, and that the

  11. Long-term motor cortex stimulation for phantom limb pain.

    Science.gov (United States)

    Pereira, Erlick A C; Moore, Tom; Moir, Liz; Aziz, Tipu Z

    2015-04-01

    We present the long-term course of motor cortex stimulation to relieve a case of severe burning phantom arm pain after brachial plexus injury and amputation. During 16-year follow-up the device continued to provide efficacious analgesia. However, several adjustments of stimulation parameters were required, as were multiple pulse generator changes, antibiotics for infection and one electrode revision due to lead migration. Steady increases in stimulation parameters over time were required. One of the longest follow-ups of motor cortex stimulation is described; the case illustrates challenges and pitfalls in neuromodulation for chronic pain, demonstrating strategies for maintaining analgesia and overcoming tolerance. PMID:25340991

  12. Assembly language programming ARM Cortex-M3

    CERN Document Server

    Mahout, Vincent

    2013-01-01

    ARM designs the cores of microcontrollers which equip most "embedded systems" based on 32-bit processors. Cortex M3 is one of these designs, recently developed by ARM with microcontroller applications in mind. To conceive a particularly optimized piece of software (as is often the case in the world of embedded systems) it is often necessary to know how to program in an assembly language.This book explains the basics of programming in an assembly language, while being based on the architecture of Cortex M3 in detail and developing many examples.It is written for people who have never pr

  13. Three-dimensional microtomographic imaging of human brain cortex

    CERN Document Server

    Mizutania, Ryuta; Uesugi, Kentaro; Ohyama, Masami; Takekoshi, Susumu; Osamura, R Yoshiyuki; Suzuki, Yoshio

    2016-01-01

    This paper describes an x-ray microtomographic technique for imaging the three-dimensional structure of the human cerebral cortex. Neurons in the brain constitute a neural circuit as a three-dimensional network. The brain tissue is composed of light elements that give little contrast in a hard x-ray transmission image. The contrast was enhanced by staining neural cells with metal compounds. The obtained structure revealed the microarchitecture of the gray and white matter regions of the frontal cortex, which is responsible for the higher brain functions.

  14. Activation of cannabinoid system in anterior cingulate cortex and orbitofrontal cortex modulates cost-benefit decision making

    OpenAIRE

    Khani, Abbas; Kermani, Mojtaba; Hesam, 6Soghra; Haghparast, Abbas; Enrike G Argandoña; Rainer, Gregor

    2015-01-01

    Despite the evidence for altered decision making in cannabis abusers, the role of the cannabinoid system in decision-making circuits has not been studied. Here, we examined the effects of cannabinoid modulation during cost-benefit decision making in the anterior cingulate cortex (ACC) and orbitofrontal cortex (OFC), key brain areas involved in decision making. We trained different groups of rats in a delay-based and an effort-based form of cost-benefit T-maze decision-making task. During test...

  15. A Mediating Role of the Premotor Cortex in Phoneme Segmentation

    Science.gov (United States)

    Sato, Marc; Tremblay, Pascale; Gracco, Vincent L.

    2009-01-01

    Consistent with a functional role of the motor system in speech perception, disturbing the activity of the left ventral premotor cortex by means of repetitive transcranial magnetic stimulation (rTMS) has been shown to impair auditory identification of syllables that were masked with white noise. However, whether this region is crucial for speech…

  16. Impulsivity, the orbifrontal cortex and borderline personality disorder

    OpenAIRE

    Berlin, Heather.; Iverson, Susan.; Edmund Rolls, Susan Iverson

    2003-01-01

    Damage to the orbitofrontal cortex (OFC) has been associated with disinhibited or socially inappropriate behaviour and emotional irregularities in both humans and monkeys. Prominent characteristics of several personality disorder syndromes, in particular Borderline Personality Disorder (BPD), are impulsivity and affective instability. This investigation aimed to determine if certain aspects of the Borderline Personality syndrome, in particular impulsivity, are associated with ...

  17. 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. PMID:24855114

  18. Development of Rostral Prefrontal Cortex and Cognitive and Behavioural Disorders

    Science.gov (United States)

    Dumontheil, Iroise; Burgess, Paul W.; Blakemore, Sarah-Jayne

    2008-01-01

    Information on the development and functions of rostral prefrontal cortex (PFC), or Brodmann area 10, has been gathered from different fields, from anatomical development to functional neuroimaging in adults, and put forward in relation to three particular cognitive and behavioural disorders. Rostral PFC is larger and has a lower cell density in…

  19. Adrenal cortex glucocorticoid function at irradiated animals on mumio leading

    International Nuclear Information System (INIS)

    In this chapter author made conclusion that the leading of mumio preparation provide normalizing influence on hypophysis-cortex adrenal system not only at short-term irradiation but and at long-term irradiation that is propitious condition for normalisation exchange processes in the cells

  20. Wrinkling of a spherical lipid interface induced by actomyosin cortex

    Science.gov (United States)

    Ito, Hiroaki; Nishigami, Yukinori; Sonobe, Seiji; Ichikawa, Masatoshi

    2015-12-01

    Actomyosin actively generates contractile forces that provide the plasma membrane with the deformation stresses essential to carry out biological processes. Although the contractile property of purified actomyosin has been extensively studied, to understand the physical contribution of the actomyosin contractile force on a deformable membrane is still a challenging problem and of great interest in the field of biophysics. Here, we reconstitute a model system with a cell-sized deformable interface that exhibits anomalous curvature-dependent wrinkling caused by the actomyosin cortex underneath the spherical closed interface. Through a shape analysis of the wrinkling deformation, we find that the dominant contributor to the wrinkled shape changes from bending elasticity to stretching elasticity of the reconstituted cortex upon increasing the droplet curvature radius of the order of the cell size, i.e., tens of micrometers. The observed curvature dependence is explained by the theoretical description of the cortex elasticity and contractility. Our present results provide a fundamental insight into the deformation of a curved membrane induced by the actomyosin cortex.

  1. Functional sex differences in human primary auditory cortex

    NARCIS (Netherlands)

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

    2007-01-01

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

  2. Daily rhythm of synapse turnover in mouse somatosensory cortex.

    Science.gov (United States)

    Jasinska, Malgorzata; Grzegorczyk, Anna; Jasek, Ewa; Litwin, Jan A; Kossut, Malgorzata; Barbacka-Surowiak, Grazyna; Pyza, Elzbieta

    2014-01-01

    The whisker representations in the somatosensory barrel cortex of mice are modulated by sensory inputs associated with animal motor behavior which shows circadian rhythmicity. In a C57/BL mouse strain kept under a light/dark (LD 12:12) regime, we observed daily structural changes in the barrel cortex, correlated with the locomotor activity level. Stereological analysis of serial electron microscopic sections of the barrel cortex of mice sacrificed during their active or rest period, revealed an increase in the total numerical density of synapses and in the density of excitatory synapses located on dendritic spines during the rest, as well as an increase in the density of inhibitory synapses located on double-synapse spines during the active period. This is the first report demonstrating a daily rhythm in remodeling of the mammalian somatosensory cortex, manifested by changes in the density of synapses and dendritic spines. Moreover, we have found that the excitatory and inhibitory synapses are differently regulated during the day/night cycle. PMID:24718049

  3. Anterior Cingulate Cortex in Schema Assimilation and Expression

    Science.gov (United States)

    Wang, Szu-Han; Tse, Dorothy; Morris, Richard G. M.

    2012-01-01

    In humans and in animals, mental schemas can store information within an associative framework that enables rapid and efficient assimilation of new information. Using a hippocampal-dependent paired-associate task, we now report that the anterior cingulate cortex is part of a neocortical network of schema storage with NMDA receptor-mediated…

  4. Spindle neurons of the human anterior cingulate cortex

    Science.gov (United States)

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

    1995-01-01

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

  5. Androgen receptor immunoreactivity in rat occipital cortex after callosotomy

    Directory of Open Access Journals (Sweden)

    G Lepore

    2009-08-01

    Full Text Available Gonadal steroidogenesis can be influenced by direct neural links between the central nervous system and the gonads. It is known that androgen receptor (AR is expressed in many areas of the rat brain involved in neuroendocrine control of reproduction, such as the cerebral cortex. It has been recently shown that the occipital cortex exerts an inhibitory effect on testicular stereoidogenesis by a pituitary-independent neural mechanism. Moreover, the complete transection of the corpus callosum leads to an increase in testosterone (T secretion of hemigonadectomized rats. The present study was undertaken to analyze the possible corticocortical influences regulating male reproductive activities. Adult male Wistar rats were divided into 4 groups: 1 intact animals as control; 2 rats undergoing sham callosotomy; 3 posterior callosotomy; 4 gonadectomy and posterior callosotomy. Western blot analysis showed no remarkable variations in cortical AR expression in any of the groups except in group I where a significant decrease in AR levels was found. Similarly, both immunocytochemical study and cell count estimation showed a lower AR immunoreactivity in occipital cortex of callosotomized rats than in other groups. In addition, there was no difference in serum T and LH concentration between sham-callosotomized and callosotomized rats. In conclusion, our results show that posterior callosotomy led to a reduction in AR in the right occipital cortex suggesting a putative inhibiting effect of the contralateral cortical area.

  6. The Role of the Insular Cortex in Retaliation

    Science.gov (United States)

    Lobbestael, Jill; Arntz, Arnoud; Brugman, Suzanne; Sack, Alexander Thomas

    2016-01-01

    The insular cortex has consistently been associated with various aspects of emotion regulation and social interaction, including anger processing and overt aggression. Aggression research distinguishes proactive or instrumental aggression from retaliation, i.e. aggression in response to provocation. Here, we investigated the specific role of the insular cortex during retaliation, employing a controlled behavioral aggression paradigm implementing different levels of provocation. Fifteen healthy male volunteers underwent whole brain functional magnetic resonance imaging (fMRI) to identify brain regions involved in interaction with either a provoking or a non-provoking opponent. FMRI group analyses were complemented by examining the parametric modulations of brain activity related to the individual level of displayed aggression. These analyses identified a hemispheric lateralization as well as an anatomical segregation of insular cortex with specifically the left posterior part being involved in retaliation. The left-lateralization of insular activity during retaliation is in accordance with evidence from electro-physiological studies, suggesting left-lateralized fronto-cortical dominance during anger processing and aggressive acts. The posterior localization of insular activity, on the other hand, suggests a spatial segregation within insular cortex with particularly the posterior part being involved in the processing of emotions that trigger intense bodily sensations and immediate action tendencies. PMID:27096431

  7. Functional sex differences in human primary auditory cortex

    International Nuclear Information System (INIS)

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

  8. Immunoprofiling of rice root cortex reveals two cortical subdomains

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    Sophia eHenry

    2016-01-01

    Full Text Available The formation and differentiation of aerenchyma, i.e., air-containing cavities that are critical for flooding tolerance, take place exclusively in the cortex. The understanding of development and differentiation of the cortex is thus an important issue; however, studies on this tissue are limited, partly because of the lack of available molecular tools. We screened a commercially available library of cell wall antibodies to identify markers of cortical tissue in rice roots. Out of the 174 antibodies screened, eight were cortex-specific. Our analysis revealed that two types of cortical tissues are present in rice root seedlings. We named these cell layers 'inner' and 'outer' based on their location relative to the stele. We then used the antibodies to clarify cell identity in lateral roots. Without these markers, previous studies could not distinguish between the cortex and sclerenchyma in small lateral roots. By immunostaining lateral root sections, we showed that the internal ground tissue in small lateral roots has outer cortical identity.

  9. Orientation-tuned surround suppression in mouse visual cortex

    NARCIS (Netherlands)

    Self, Matthew W; Lorteije, Jeannette A M; Vangeneugden, Joris; van Beest, Enny H; Grigore, Mihaela E; Levelt, Christiaan N; Heimel, J.A.; Roelfsema, Pieter R

    2014-01-01

    The firing rates of neurons in primary visual cortex (V1) are suppressed by large stimuli, an effect known as surround suppression. In cats and monkeys, the strength of suppression is sensitive to orientation; responses to regions containing uniform orientations are more suppressed than those contai

  10. Extinction Circuits for Fear and Addiction Overlap in Prefrontal Cortex

    Science.gov (United States)

    Peters, Jamie; Kalivas, Peter W.; Quirk, Gregory J.

    2009-01-01

    Extinction is a form of inhibitory learning that suppresses a previously conditioned response. Both fear and drug seeking are conditioned responses that can lead to maladaptive behavior when expressed inappropriately, manifesting as anxiety disorders and addiction, respectively. Recent evidence indicates that the medial prefrontal cortex (mPFC) is…

  11. Perceptual Learning and Dynamic Changes in Primary Visual Cortex

    OpenAIRE

    Carmel, David; Carrasco, Marisa

    2008-01-01

    Perceptual learning is the improved performance that follows practice in a perceptual task. In this issue of Neuron, Yotsumoto et al. use fMRI to show that stimuli presented at the location used in training initially evoke greater activation in primary visual cortex than stimuli presented elsewhere, but this difference disappears once learning asymptotes.

  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. PMID:26975554

  13. Towards a circuit mechanism for movement tuning in motor cortex

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    Thomas C Harrison

    2013-01-01

    Full Text Available The firing rates of neurons in primate motor cortex have been related to multiple parameters of voluntary movement. This finding has been corroborated by stimulation-based studies that have mapped complex movements in rodent and primate motor cortex. However, it has been difficult to link the movement tuning of a neuron with its role within the cortical microcircuit. In sensory cortex, neuronal tuning is largely established by afferents delivering information from tuned receptors in the periphery. Motor cortex, which lacks the granular input layer, may be better understood by analyzing its efferent projections. As a primary source of cortical output, layer 5 neurons represent an ideal starting point for this line of experimentation. It is in these deep output layers that movements can most effectively be evoked by intracortical microstimulation and recordings can obtain the most useful signals for the control of motor prostheses. Studies focused on layer 5 output neurons have revealed that projection identity is a fundamental property related to the laminar position, receptive field and ion channel complement of these cells. Given the variety of brain areas targeted by layer 5 output neurons, knowledge of a neuron’s downstream connectivity may provide insight into its movement tuning. Future experiments that relate motor behavior to the activity of neurons with a known projection identity will yield a more detailed understanding of the function of cortical microcircuits.

  14. Role of Frontal Cortex in Attentional Capture by Singleton Distractors

    Science.gov (United States)

    de Fockert, Jan W.; Theeuwes, Jan

    2012-01-01

    The role of frontal cortex in selective attention to visual distractors was examined in an attentional capture task in which participants searched for a unique shape in the presence or absence of an additional colour singleton distractor. The presence of the additional singleton was associated with slower behavioural responses to the shape target,…

  15. Motor cortex guides selection of predictable movement targets

    Science.gov (United States)

    Woodgate, Philip J.W.; Strauss, Soeren; Sami, Saber A.; Heinke, Dietmar

    2016-01-01

    The present paper asks whether the motor cortex contributes to prediction-based guidance of target selection. This question was inspired by recent evidence that suggests (i) recurrent connections from the motor system into the attentional system may extract movement-relevant perceptual information and (ii) that the motor cortex cannot only generate predictions of the sensory consequences of movements but may also operate as predictor of perceptual events in general. To test this idea we employed a choice reaching task requiring participants to rapidly reach and touch a predictable or unpredictable colour target. Motor cortex activity was modulated via transcranial direct current stimulation (tDCS). In Experiment 1 target colour repetitions were predictable. Under such conditions anodal tDCS facilitated selection versus sham and cathodal tDCS. This improvement was apparent for trajectory curvature but not movement initiation. Conversely, where no predictability of colour was embedded reach performance was unaffected by tDCS. Finally, the results of a key-press experiment suggested that motor cortex involvement is restricted to tasks where the predictable target colour is movement-relevant. The outcomes are interpreted as evidence that the motor system contributes to the top-down guidance of selective attention to movement targets. PMID:25835319

  16. Functional sex differences in human primary auditory cortex

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-12-15

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

  17. Neural Dynamics and Information Representation in Microcircuits of Motor Cortex

    Directory of Open Access Journals (Sweden)

    Yasuhiro eTsubo

    2013-05-01

    Full Text Available The brain has to analyze and respond to external events that can change rapidly from time to time, suggesting that information processing by the brain may be essentially dynamic rather than static. The dynamical features of neural computation are of significant importance in motor cortex that governs the process of movement generation and learning. In this paper, we discuss these features based primarily on our recent findings on neural dynamics and information coding in the microcircuit of rat motor cortex. In fact, cortical neurons show a variety of dynamical behavior from rhythmic activity in various frequency bands to highly irregular spike firing. Of particular interest are the similarity and dissimilarity of the neuronal response properties in different layers of motor cortex. By conducting electrophysiological recordings in slice preparation, we report the phase response curves of neurons in different cortical layers to demonstrate their layer-dependent synchronization properties. We then study how motor cortex recruits task-related neurons in different layers for voluntary arm movements by simultaneous juxtacellular and multiunit recordings from behaving rats. The results suggest an interesting difference in the spectrum of functional activity between the superficial and deep layers. Furthermore, the task-related activities recorded from various layers exhibited power law distributions of inter-spike intervals (ISIs, in contrast to a general belief that ISIs obey Poisson or Gamma distributions in cortical neurons. We present a theoretical argument that this power law of in vivo neurons may represent the maximization of the entropy of firing rate with limited energy consumption of spike generation. Though further studies are required to fully clarify the functional implications of this coding principle, it may shed new light on information representations by neurons and circuits in motor cortex.

  18. 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. PMID:22282486

  19. Music perception and cognition following bilateral lesions of auditory cortex.

    Science.gov (United States)

    Tramo, M J; Bharucha, J J; Musiek, F E

    1990-01-01

    We present experimental and anatomical data from a case study of impaired auditory perception following bilateral hemispheric strokes. To consider the cortical representation of sensory, perceptual, and cognitive functions mediating tonal information processing in music, pure tone sensation thresholds, spectral intonation judgments, and the associative priming of spectral intonation judgments by harmonic context were examined, and lesion localization was analyzed quantitatively using straight-line two-dimensional maps of the cortical surface reconstructed from magnetic resonance images. Despite normal pure tone sensation thresholds at 250-8000 Hz, the perception of tonal spectra was severely impaired, such that harmonic structures (major triads) were almost uniformly judged to sound dissonant; yet, the associative priming of spectral intonation judgments by harmonic context was preserved, indicating that cognitive representations of tonal hierarchies in music remained intact and accessible. Brainprints demonstrated complete bilateral lesions of the transverse gyri of Heschl and partial lesions of the right and left superior temporal gyri involving 98 and 20% of their surface areas, respectively. In the right hemisphere, there was partial sparing of the planum temporale, temporoparietal junction, and inferior parietal cortex. In the left hemisphere, all of the superior temporal region anterior to the transverse gyrus and parts of the planum temporale, temporoparietal junction, inferior parietal cortex, and insula were spared. These observations suggest that (1) sensory, perceptual, and cognitive functions mediating tonal information processing in music are neurologically dissociable; (2) complete bilateral lesions of primary auditory cortex combined with partial bilateral lesions of auditory association cortex chronically impair tonal consonance perception; (3) cognitive functions that hierarchically structure pitch information and generate harmonic expectancies

  20. Selecting category specific visual information: Top-down and bottom-up control of object based attention.

    Science.gov (United States)

    Corradi-Dell'Acqua, Corrado; Fink, Gereon R; Weidner, Ralph

    2015-09-01

    The ability to select, within the complexity of sensory input, the information most relevant for our purposes is influenced by both internal settings (i.e., top-down control) and salient features of external stimuli (i.e., bottom-up control). We here investigated using fMRI the neural underpinning of the interaction of top-down and bottom-up processes, as well as their effects on extrastriate areas processing visual stimuli in a category-selective fashion. We presented photos of bodies or buildings embedded into frequency-matched visual noise to the subjects. Stimulus saliency changed gradually due to an altered degree to which photos stood-out in relation to the surrounding noise (hence generating stronger bottom-up control signals). Top-down settings were manipulated via instruction: participants were asked to attend one stimulus category (i.e., "is there a body?" or "is there a building?"). Highly salient stimuli that were inconsistent with participants' attentional top-down template activated the inferior frontal junction and dorsal parietal regions bilaterally. Stimuli consistent with participants' current attentional set additionally activated insular cortex and the parietal operculum. Furthermore, the extrastriate body area (EBA) exhibited increased neural activity when attention was directed to bodies. However, the latter effect was found only when stimuli were presented at intermediate saliency levels, thus suggesting a top-down modulation of this region only in the presence of weak bottom-up signals. Taken together, our results highlight the role of the inferior frontal junction and posterior parietal regions in integrating bottom-up and top-down attentional control signals. PMID:25735196

  1. Trans-saccadic interactions in human parietal and occipital cortex during the retention and comparison of object orientation.

    Science.gov (United States)

    Dunkley, Benjamin T; Baltaretu, Bianca; Crawford, J Douglas

    2016-09-01

    The cortical sites for the trans-saccadic storage and integration of visual object features are unknown. Here, we used a variant of fMRI-Adaptation where subjects fixated to the left or right of a briefly presented visual grating, maintained fixation or saccaded to the opposite side, then judged whether a re-presented grating had the same or different orientation. fMRI analysis revealed trans-saccadic interactions (different > same orientation) in a visual field-insensitive cluster within right supramarginal gyrus. This cluster was located at the anterolateral pole of the parietal eye field (identified in a localizer task). We also observed gaze centered, field-specific interactions (same > different orientation) in an extrastriate cluster overlapping with putative 'V4'. Based on these data and our literature review, we conclude that these supramarginal and extrastriate areas are involved in the retention, spatial updating, and evaluation of object orientation information across saccades. PMID:27424061

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

    Science.gov (United States)

    Chen, Joyce L; Schlaug, Gottfried

    2016-01-01

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

  3. Golgi Analysis of Neuron Morphology in the Presumptive Somatosensory Cortex and Visual Cortex of the Florida Manatee (Trichechus manatus latirostris).

    Science.gov (United States)

    Reyes, Laura D; Harland, Tessa; Reep, Roger L; Sherwood, Chet C; Jacobs, Bob

    2016-01-01

    The current study investigates neuron morphology in presumptive primary somatosensory (S1) and primary visual (V1) cortices of the Florida manatee (Trichechus manatus latirostris) as revealed by Golgi impregnation. Sirenians, including manatees, have an aquatic lifestyle, a large body size, and a relatively large lissencephalic brain. The present study examines neuron morphology in 3 cortical areas: in S1, dorsolateral cortex area 1 (DL1) and cluster cortex area 2 (CL2) and in V1, dorsolateral cortex area 4 (DL4). Neurons exhibited a variety of morphological types, with pyramidal neurons being the most common. The large variety of neuron types present in the manatee cortex was comparable to that seen in other eutherian mammals, except for rodents and primates, where pyramid-shaped neurons predominate. A comparison between pyramidal neurons in S1 and V1 indicated relatively greater dendritic branching in S1. Across all 3 areas, the dendritic arborization pattern of pyramidal neurons was also similar to that observed previously in the afrotherian rock hyrax, cetartiodactyls, opossums, and echidnas but did not resemble the widely bifurcated dendrites seen in the large-brained African elephant. Despite adaptations for an aquatic environment, manatees did not share specific neuron types such as tritufted and star-like neurons that have been found in cetaceans. Manatees exhibit an evolutionarily primitive pattern of cortical neuron morphology shared with most other mammals and do not appear to have neuronal specializations for an aquatic niche. PMID:27166161

  4. Subclinical delusional thinking predicts lateral temporal cortex responses during social reflection

    OpenAIRE

    Brent, Benjamin K.; Coombs, Garth; Keshavan, Matcheri S.; Seidman, Larry J.; Moran, Joseph M.; Holt, Daphne J.

    2012-01-01

    Neuroimaging studies have demonstrated associations between delusions in psychotic disorders and abnormalities of brain areas involved in social cognition, including medial prefrontal cortex (MPFC), posterior cingulate cortex, and lateral temporal cortex (LTC). General population studies have linked subclinical delusional thinking to impaired social cognition, raising the question of whether a specific pattern of brain activity during social perception is associated with delusional beliefs. H...

  5. Increased stress vulnerability after a prefrontal cortex lesion in female rats

    NARCIS (Netherlands)

    Gerrits, M; Westenbroek, C; Fokkema, DS; Jongsma, ME; Den Boer, JA; Ter Horst, GJ

    2003-01-01

    Neuroimaging studies in patients suffering from affective disorders have shown decreased volume and reduced regional cerebral blood flow in multiple areas of the prefrontal cortex, including the medial prefrontal cortex and the orbitofrontal cortex. This aberrant brain activity is among other things

  6. Peripheral nerve injury induces glial activation in primary motor cortex

    Directory of Open Access Journals (Sweden)

    Julieta Troncoso

    2015-02-01

    Full Text Available Preliminary evidence suggests that peripheral facial nerve injuries are associated with sensorimotor cortex reorganization. We have characterized facial nerve lesion-induced structural changes in primary motor cortex layer 5 pyramidal neurons and their relationship with glial cell density using a rodent facial paralysis model. First, we used adult transgenic mice expressing green fluorescent protein in microglia and yellow fluorescent protein in pyramidal neurons which were subjected to either unilateral lesion of the facial nerve or sham surgery. Two-photon excitation microscopy was then used for evaluating both layer 5 pyramidal neurons and microglia in vibrissal primary motor cortex (vM1. It was found that facial nerve lesion induced long-lasting changes in dendritic morphology of vM1 layer 5 pyramidal neurons and in their surrounding microglia. Pyramidal cells’ dendritic arborization underwent overall shrinkage and transient spine pruning. Moreover, microglial cell density surrounding vM1 layer 5 pyramidal neurons was significantly increased with morphological bias towards the activated phenotype. Additionally, we induced facial nerve lesion in Wistar rats to evaluate the degree and extension of facial nerve lesion-induced reorganization processes in central nervous system using neuronal and glial markers. Immunoreactivity to NeuN (neuronal nuclei antigen, GAP-43 (growth-associated protein 43, GFAP (glial fibrillary acidic protein, and Iba 1 (Ionized calcium binding adaptor molecule 1 were evaluated 1, 3, 7, 14, 28 and 35 days after either unilateral facial nerve lesion or sham surgery. Patches of decreased NeuN immunoreactivity were found bilaterally in vM1 as well as in primary somatosensory cortex (CxS1. Significantly increased GAP-43 immunoreactivity was found bilaterally after the lesion in hippocampus, striatum, and sensorimotor cortex. One day after lesion GFAP immunoreactivity increased bilaterally in hippocampus, subcortical white

  7. Sensory experience modifies feature map relationships in visual cortex.

    Science.gov (United States)

    Cloherty, Shaun L; Hughes, Nicholas J; Hietanen, Markus A; Bhagavatula, Partha S; Goodhill, Geoffrey J; Ibbotson, Michael R

    2016-01-01

    The extent to which brain structure is influenced by sensory input during development is a critical but controversial question. A paradigmatic system for studying this is the mammalian visual cortex. Maps of orientation preference (OP) and ocular dominance (OD) in the primary visual cortex of ferrets, cats and monkeys can be individually changed by altered visual input. However, the spatial relationship between OP and OD maps has appeared immutable. Using a computational model we predicted that biasing the visual input to orthogonal orientation in the two eyes should cause a shift of OP pinwheels towards the border of OD columns. We then confirmed this prediction by rearing cats wearing orthogonally oriented cylindrical lenses over each eye. Thus, the spatial relationship between OP and OD maps can be modified by visual experience, revealing a previously unknown degree of brain plasticity in response to sensory input. PMID:27310531

  8. Sensory experience modifies feature map relationships in visual cortex

    Science.gov (United States)

    Cloherty, Shaun L; Hughes, Nicholas J; Hietanen, Markus A; Bhagavatula, Partha S

    2016-01-01

    The extent to which brain structure is influenced by sensory input during development is a critical but controversial question. A paradigmatic system for studying this is the mammalian visual cortex. Maps of orientation preference (OP) and ocular dominance (OD) in the primary visual cortex of ferrets, cats and monkeys can be individually changed by altered visual input. However, the spatial relationship between OP and OD maps has appeared immutable. Using a computational model we predicted that biasing the visual input to orthogonal orientation in the two eyes should cause a shift of OP pinwheels towards the border of OD columns. We then confirmed this prediction by rearing cats wearing orthogonally oriented cylindrical lenses over each eye. Thus, the spatial relationship between OP and OD maps can be modified by visual experience, revealing a previously unknown degree of brain plasticity in response to sensory input. DOI: http://dx.doi.org/10.7554/eLife.13911.001 PMID:27310531

  9. Retrosplenial cortex maps the conjunction of internal and external spaces.

    Science.gov (United States)

    Alexander, Andrew S; Nitz, Douglas A

    2015-08-01

    Intelligent behavior demands not only multiple forms of spatial representation, but also coordination among the brain regions mediating those representations. Retrosplenial cortex is densely interconnected with the majority of cortical and subcortical brain structures that register an animal's position in multiple internal and external spatial frames of reference. This unique anatomy suggests that it functions to integrate distinct forms of spatial information and provides an interface for transformations between them. Evidence for this was found in rats traversing two different routes placed at different environmental locations. Retrosplenial ensembles robustly encoded conjunctions of progress through the current route, position in the larger environment and the left versus right turning behavior of the animal. Thus, the retrosplenial cortex has the requisite dynamics to serve as an intermediary between brain regions generating different forms of spatial mapping, a result that is consistent with navigational and episodic memory impairments following damage to this region in humans. PMID:26147532

  10. Causal evidence for frontal cortex organization for perceptual decision making.

    Science.gov (United States)

    Rahnev, Dobromir; Nee, Derek Evan; Riddle, Justin; Larson, Alina Sue; D'Esposito, Mark

    2016-05-24

    Although recent research has shown that the frontal cortex has a critical role in perceptual decision making, an overarching theory of frontal functional organization for perception has yet to emerge. Perceptual decision making is temporally organized such that it requires the processes of selection, criterion setting, and evaluation. We hypothesized that exploring this temporal structure would reveal a large-scale frontal organization for perception. A causal intervention with transcranial magnetic stimulation revealed clear specialization along the rostrocaudal axis such that the control of successive stages of perceptual decision making was selectively affected by perturbation of successively rostral areas. Simulations with a dynamic model of decision making suggested distinct computational contributions of each region. Finally, the emergent frontal gradient was further corroborated by functional MRI. These causal results provide an organizational principle for the role of frontal cortex in the control of perceptual decision making and suggest specific mechanistic contributions for its different subregions. PMID:27162349

  11. Not so "silent":The human prefrontal cortex

    Directory of Open Access Journals (Sweden)

    Prakash Narain Tandon

    2013-01-01

    Full Text Available Little was known about the human prefrontal cortex till recently. It was thus labeled as the "silent area," "uncommitted cortex." It not only constitutes the largest component of the human brain but is the latest evolutionary addition to the mammalian brain. It endows the human beings with qualities that differentiate humans from all other animals. During the last couple of decades the advent of modern electrophysiological and imaging (functional magnetic resonance imaging, proton emission tomography, SPECT techniques have provided a wealth of insight into its role in memory, thought, emotions, moral judgment, social behavior, evaluating rewards, and assessing its fairness or otherwise and above all self-awareness. This brief review summarize the recent significant observations on its functions and connectivity which would interest the cognitive scientists and clinicians alike.

  12. What must a global theory of cortex explain?

    Science.gov (United States)

    Valiant, Leslie G

    2014-04-01

    At present there is no generally accepted theory of how cognitive phenomena arise from computations in cortex. Further, there is no consensus on how the search for one should be refocussed so as to make it more fruitful. In this short piece we observe that research in computer science over the last several decades has shown that significant computational phenomena need to circumvent significant inherent quantitative impediments, such as of computational complexity. We argue that computational neuroscience has to be informed by the same quantitative concerns for it to succeed. It is conceivable that the brain is the one computation that does not need to circumvent any such obstacles, but if that were the case then quantitatively plausible theories of cortex would now surely abound and be driving experimental investigations. PMID:24709595

  13. The hippocampus as a stable memory allocator for cortex.

    Science.gov (United States)

    Valiant, Leslie G

    2012-11-01

    It is suggested here that mammalian hippocampus serves as an allocator of neurons in cortex for memorizing new items. A construction of a shallow feedforward network with biologically plausible parameters is given that possesses the characteristics needed for such an allocator. In particular, the construction is stabilizing in that for inputs within a range of activity levels spanning more than an order of magnitude, the output will have activity levels differing as little as 1%. It is also noise tolerant in that pairs of input patterns that differ little will generate output patterns that differ little. Further, pairs of inputs that differ by much will be mapped to outputs that also differ sufficiently that they can be treated by cortex as distinct. PMID:22920849

  14. Subplate in the developing cortex of mouse and human

    DEFF Research Database (Denmark)

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

    2010-01-01

    Abstract The subplate is a largely transient zone containing precocious neurons involved in several key steps of cortical development. The majority of subplate neurons form a compact layer in mouse, but are dispersed throughout a much larger zone in the human. In rodent, subplate neurons are among...... the earliest born neocortical cells, whereas in primate, neurons are added to the subplate throughout cortical neurogenesis. Magnetic resonance imaging and histochemical studies show that the human subplate grows in size until the end of the second trimester. Previous microarray experiments in mice...... have shown several genes that are specifically expressed in the subplate layer of the rodent dorsal cortex. Here we examined the human subplate for some of these markers. In the human dorsal cortex, connective tissue growth factor-positive neurons can be seen in the ventricular zone at 15...

  15. Cerebellar networks with the cerebral cortex and basal ganglia.

    Science.gov (United States)

    Bostan, Andreea C; Dum, Richard P; Strick, Peter L

    2013-05-01

    The dominant view of cerebellar function has been that it is exclusively concerned with motor control and coordination. Recent findings from neuroanatomical, behavioral, and imaging studies have profoundly changed this view. Neuroanatomical studies using virus transneuronal tracers have demonstrated that cerebellar output reaches vast areas of the neocortex, including regions of prefrontal and posterior parietal cortex. Furthermore, it has recently become clear that the cerebellum is reciprocally connected with the basal ganglia, which suggests that the two subcortical structures are part of a densely interconnected network. Taken together, these findings elucidate the neuroanatomical substrate for cerebellar involvement in non-motor functions mediated by the prefrontal and posterior parietal cortex, as well as in processes traditionally associated with the basal ganglia. PMID:23579055

  16. Neural Anatomy of Primary Visual Cortex Limits Visual Working Memory.

    Science.gov (United States)

    Bergmann, Johanna; Genç, Erhan; Kohler, Axel; Singer, Wolf; Pearson, Joel

    2016-01-01

    Despite the immense processing power of the human brain, working memory storage is severely limited, and the neuroanatomical basis of these limitations has remained elusive. Here, we show that the stable storage limits of visual working memory for over 9 s are bound by the precise gray matter volume of primary visual cortex (V1), defined by fMRI retinotopic mapping. Individuals with a bigger V1 tended to have greater visual working memory storage. This relationship was present independently for both surface size and thickness of V1 but absent in V2, V3 and for non-visual working memory measures. Additional whole-brain analyses confirmed the specificity of the relationship to V1. Our findings indicate that the size of primary visual cortex plays a critical role in limiting what we can hold in mind, acting like a gatekeeper in constraining the richness of working mental function. PMID:25100854

  17. Higher Order Spike Synchrony in Prefrontal Cortex during visual memory

    Directory of Open Access Journals (Sweden)

    Gordon ePipa

    2011-06-01

    Full Text Available Precise temporal synchrony of spike firing has been postulated as an important neuronal mechanism for signal integration and the induction of plasticity in neocortex. As prefrontal cortex plays an important role in organizing memory and executive functions, the convergence of multiple visual pathways onto PFC predicts that neurons should preferentially synchronize their spiking when stimulus information is processed. Furthermore, synchronous spike firing should intensify if memory processes require the induction of neuronal plasticity, even if this is only for short-term. Here we show with multiple simultaneously recorded units in ventral prefrontal cortex that neurons participate in 3 ms precise synchronous discharges distributed across multiple sites separated by at least 500 µm. The frequency of synchronous firing is modulated by behavioral performance and is specific for the memorized visual stimuli. In particular, during the memory period in which activity is not stimulus driven, larger groups of up to 7 sites exhibit performance dependent modulation of their spike synchronization.

  18. Insular cortex activity and the evocation of laughter.

    Science.gov (United States)

    Wattendorf, Elise; Westermann, Birgit; Lotze, Martin; Fiedler, Klaus; Celio, Marco R

    2016-06-01

    The insular cortex is fundamentally involved in the processing of interoceptive information. It has been postulated that the integrative monitoring of the bodily responses to environmental stimuli is crucial for the recognition and experience of emotions. Because emotional arousal is known to be closely coupled to functions of the anterior insula, we suspected laughter to be associated primarily with neuronal activity in this region. An anatomically constrained re-analysis of our imaging data pertaining to ticklish laughter, to inhibited ticklish laughter, and to voluntary laughter revealed regional differences in the levels of neuronal activity in the posterior and mid-/anterior portions of the insula. Ticklish laughter was associated specifically with right ventral anterior insular activity, which was not detected under the other two conditions. Hence, apparently, only laughter that is evoked as an emotional response bears the signature of autonomic arousal in the insular cortex. J. Comp. Neurol. 524:1608-1615, 2016. © 2015 Wiley Periodicals, Inc. PMID:26287648

  19. Short-term plasticity of the human auditory cortex.

    Science.gov (United States)

    Pantev, C; Wollbrink, A; Roberts, L E; Engelien, A; Lütkenhöner, B

    1999-09-18

    Magnetoencephalographic measurements (MEG) were used to examine the effect on the human auditory cortex of removing specific frequencies from the acoustic environment. Subjects listened for 3 h on three consecutive days to music "notched" by removal of a narrow frequency band centered on 1 kHz. Immediately after listening to the notched music, the neural representation for a 1-kHz test stimulus centered on the notch was found to be significantly diminished compared to the neural representation for a 0.5-kHz control stimulus centered one octave below the region of notching. The diminished neural representation for 1 kHz reversed to baseline between the successive listening sessions. These results suggest that rapid changes can occur in the tuning of neurons in the adult human auditory cortex following manipulation of the acoustic environment. A dynamic form of neural plasticity may underlie the phenomenon observed here. PMID:10526109

  20. 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. PMID:18824074

  1. Functional magnetic resonance imaging evaluation of visual cortex activation in patients with anterior visual pathway lesions

    Institute of Scientific and Technical Information of China (English)

    Xiufeng Song; Guohua Wang; Tong Zhang; Lei Feng; Peng An; Yueli Zhu

    2012-01-01

    The aim of this study was to examine the secondary visual cortex functional disorder in patients with glaucoma and large pituitary adenoma by functional magnetic resonance imaging, and to determine the correlation between visual field defect and primary visual cortex activation. Results showed that single eye stimulation resulted in bilateral visual cortex activation in patients with glaucoma or large pituitary adenoma. Compared with the normal control group, the extent and intensity of visual cortex activation was decreased after left and right eye stimulation, and functional magnetic resonance imaging revealed a correlation between visual field defects and visual cortex activation in patients with glaucoma and large pituitary adenoma. These functional magnetic resonance imaging data suggest that anterior optic pathway lesions can cause secondary functional disorder of the visual cortex, and that visual defects are correlated with visual cortex activation.

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

    Directory of Open Access Journals (Sweden)

    Annie Wai Yiu Chan

    2013-07-01

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

  3. Chronic Unpredictable Stress Promotes Neuronal Apoptosis in the Cerebral Cortex

    OpenAIRE

    Bachis, Alessia; Cruz, Maria Idalia; Nosheny, Rachael L.; Mocchetti, Italo

    2008-01-01

    Stress-mediated loss of synaptogenesis in the hippocampus appears to play a role in depressive and mood disorders. However, little is known about the effect of stress/depression on the plasticity and survival of cortical neurons. In this report, we have examined whether chronic stress increases the vulnerability of neurons in the rat cortex. We have used a chronic unpredictable mild stress (CMS) as a rat model of depression. CMS (5 weeks treatment) produced anedonia and increased corticostero...

  4. Motor cortex electric stimulation for the treatment of neuropathic pain

    OpenAIRE

    Walter J. Fagundes-Pereyra; Manoel Jacobsen Teixeira; Nicolas Reyns; Gustavo Touzet; Sérgio Dantas; Emmanuelle Laureau; Serge Blond

    2010-01-01

    OBJECTIVE: Motor cortex stimulation (MCS) is considered to be an effective treatment for chronic neuropathic pain. The aim of the present study was to assess the efficacy of MCS for treating neuropathic pain. METHOD: 27 patients with chronic neuropathic pain were operated. Electrodes were implanted with the use of an stereotactic frame. Electrophysiological evaluations (motor stimulation and somatosensory evoked potentials) were performed, with guidance by means of three-dimensional reconstru...

  5. Prefrontal Cortex Motivated Cognitive Architecture for Multiple Robots

    OpenAIRE

    Mishra, Amit Kumar; Kumar, Abhishek; Deb, Dipankar

    2014-01-01

    In this paper, we introduce a cerebral cortex inspired architecture for robots in which we have mapped hierarchical cortical representation of human brain to logic flow and decision making process. Our work focuses on the two major features of human cognitive process, viz. the perception action cycle and its hierarchical organization, and the decision making process. To prove the effectiveness of our proposed method, we incorporated this architecture in our robot which we named as Cognitive I...

  6. Stereoscopic Vision in the Absence of the Lateral Occipital Cortex

    OpenAIRE

    Read, JC; Phillipson, GP; Serrano-Pedraza, I; Milner, AD; Parker, AJ

    2010-01-01

    Both dorsal and ventral cortical visual streams contain neurons sensitive to binocular disparities, but the two streams may underlie different aspects of stereoscopic vision. Here we investigate stereopsis in the neurological patient D.F., whose ventral stream, specifically lateral occipital cortex, has been damaged bilaterally, causing profound visual form agnosia. Despite her severe damage to cortical visual areas, we report that DF's stereo vision is strikingly unimpaired. She is better th...

  7. Dynamical organization of the cytoskeletal cortex probed by micropipette aspiration

    OpenAIRE

    Brugués, Jan; Maugis, Benoit; Casademunt, Jaume; Nassoy, Pierre; Amblard, François; Sens, Pierre

    2010-01-01

    Bleb-based cell motility proceeds by the successive inflation and retraction of large spherical membrane protrusions (“blebs”) coupled with substrate adhesion. In addition to their role in motility, cellular blebs constitute a remarkable illustration of the dynamical interactions between the cytoskeletal cortex and the plasma membrane. Here we study the bleb-based motions of Entamoeba histolytica in the constrained geometry of a micropipette. We construct a generic theoretical model that comb...

  8. A Neural Circuit for Spatial Summation in Visual Cortex

    OpenAIRE

    Adesnik, Hillel; Bruns, William; Taniguchi, Hiroki; Huang, Z. Josh; Scanziani, Massimo

    2012-01-01

    The response of cortical neurons to a sensory stimulus is modulated by the context. In the visual cortex, for example, stimulation of a pyramidal cell's receptive field surround can attenuate the cell’s response to a stimulus in its receptive field’s center, a phenomenon called surround suppression. Whether cortical circuits contribute to surround suppression or whether the phenomenon is entirely relayed from earlier stages of visual processing is controversial. Here we discover that, in cont...

  9. Downregulation of the posterior medial frontal cortex prevents social conformity

    OpenAIRE

    Klucharev, V.; Munneke, M.; Smidts, A.; Fernandez, G.S.E.

    2011-01-01

    We often change our behavior to conform to real or imagined group pressure. Social influence on our behavior has been extensively studied in social psychology, but its neural mechanisms have remained largely unknown. Here we demonstrate that the transient downregulation of the posterior medial frontal cortex by theta-burst transcranial magnetic stimulation reduces conformity, as indicated by reduced conformal adjustments in line with group opinion. Both the extent and probability of conformal...

  10. Intracortical inhibition of the motor cortex is normal in chorea

    OpenAIRE

    HANAJIMA, R; Ugawa, Y; Y. Terao; Furubayashi, T.; Machii, K; Shiio, Y.; H. Enomoto; Uesugi, H.; Mochizuki, H.; Kanazawa, I

    1999-01-01

    Intracortical inhibition of the motor cortex was investigated using a paired pulse magnetic stimulation method in 14 patients with chorea caused by various aetiologies (six patients with Huntington's disease, one with chorea acanthocytosis, a patient with systemic lupus erythematosus with a vascular lesion in the caudate, three with senile chorea and three with chorea of unknown aetiology). The time course and amount of inhibition was the same in the patients as in normal su...

  11. Intersection of reward and memory in monkey rhinal cortex

    OpenAIRE

    Clark, Andrew M.; Bouret, Sebastien; Young, Adrienne M.; Barry J Richmond

    2012-01-01

    In humans and other animals the vigor with which a reward is pursued depends on its desirability, that is, on the reward’s predicted value. Predicted value is generally context dependent, varying according to the value of rewards obtained in the recent and distant past. Signals related to reward prediction and valuation are believed to be encoded in a circuit centered around midbrain dopamine neurons and their targets in the prefrontal cortex and basal ganglia. Notably absent from this hypoth...

  12. Learning warps object representations in the ventral temporal cortex

    OpenAIRE

    Clarke, Alex; Pell, Philip J.; Ranganath, Charan; Tyler, Lorraine K.

    2016-01-01

    The human ventral temporal cortex (VTC) plays a critical role in object recognition. Although it is well established that visual experience shapes VTC object representations, the impact of semantic and contextual learning is unclear. In this study, we tracked changes in representations of novel visual objects that emerged after learning meaningful information about each object. Over multiple training sessions, participants learned to associate semantic features (e.g. ?made of wood?, ?floats?)...

  13. Retinotopically defined primary visual cortex in Williams syndrome

    OpenAIRE

    Olsen, Rosanna K.; Kippenhan, J. Shane; Japee, Shruti; Kohn, Philip; Mervis, Carolyn B.; Saad, Ziad S.; Morris, Colleen A.; Meyer-Lindenberg, Andreas; Berman, Karen Faith

    2009-01-01

    Williams syndrome, caused by a hemizygous microdeletion on chromosome 7q11.23, is characterized by severe impairment in visuospatial construction. To examine potential contributions of early visual processing to this cognitive problem, we functionally mapped the size and neuroanatomical variability of primary visual cortex (V1) in high-functioning adults with Williams syndrome and age- and IQ-matched control participants from the general population by using fMRI-based retinotopic mapping and ...

  14. Exercise increases mitochondrial glutamate oxidation in the mouse cerebral cortex.

    Science.gov (United States)

    Herbst, Eric A F; Holloway, Graham P

    2016-07-01

    The present study investigated the impact of acute exercise on stimulating mitochondrial respiratory function in mouse cerebral cortex. Where pyruvate-stimulated respiration was not affected by acute exercise, glutamate respiration was enhanced following the exercise bout. Additional assessment revealed that this affect was dependent on the presence of malate and did not occur when substituting glutamine for glutamate. As such, our results suggest that glutamate oxidation is enhanced with acute exercise through activation of the malate-aspartate shuttle. PMID:27184881

  15. Orosensory and Homeostatic Functions of the Insular Taste Cortex

    OpenAIRE

    de Araujo, Ivan E; Geha, Paul; Small, Dana M.

    2012-01-01

    The gustatory aspect of the insular cortex is part of the brain circuit that controls ingestive behaviors based on chemosensory inputs. However, the sensory properties of foods are not restricted to taste and should also include salient features such as odor, texture, temperature, and appearance. Therefore, it is reasonable to hypothesize that specialized circuits within the central taste pathways must be involved in representing several other oral sensory modalities in addition to taste. In ...

  16. Insular cortex activity and the evocation of laughter

    OpenAIRE

    Wattendorf, Elise; Westermann, Birgit; Lotze, Martin; Fiedler, Klaus; Celio, Marco R.

    2015-01-01

    The insular cortex is fundamentally involved in the processing of interoceptive information. It has been postulated that the integrative monitoring of the bodily responses to environmental stimuli is crucial for the recognition and experience of emotions. Because emotional arousal is known to be closely coupled to functions of the anterior insula, we suspected laughter to be associated primarily with neuronal activity in this region. An anatomically constrained re-analysis of our imaging data...

  17. The Insular Taste Cortex Contributes to Odor Quality Coding

    OpenAIRE

    Veldhuizen, Maria G; Nachtigal, Danielle; Teulings, Lynsey; Gitelman, Darren R.; Small, Dana M.

    2010-01-01

    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 ...

  18. Auditory, Somatosensory, and Multisensory Insular Cortex in the Rat

    OpenAIRE

    Rodgers, Krista M.; Benison, Alexander M.; Klein, Andrea; Barth, Daniel S.

    2008-01-01

    Compared with other areas of the forebrain, the function of insular cortex is poorly understood. This study examined the unisensory and multisensory function of the rat insula using high-resolution, whole-hemisphere, epipial evoked potential mapping. We found the posterior insula to contain distinct auditory and somatotopically organized somatosensory fields with an interposed and overlapping region capable of integrating these sensory modalities. Unisensory and multisensory responses were un...

  19. The insular taste cortex contributes to odor quality coding

    OpenAIRE

    Gitelman, Darren R.; Small, Dana M.

    2010-01-01

    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 ...

  20. Coding of Vocalizations by Single Neurons in Ventrolateral Prefrontal Cortex

    OpenAIRE

    Plakke, Bethany; Diltz, Mark D.; Romanski, Lizabeth M.

    2013-01-01

    Neuronal activity in single prefrontal neurons has been correlated with behavioral responses, rules, task variables and stimulus features. In the non-human primate, neurons recorded in ventrolateral prefrontal cortex (VLPFC) have been found to respond to species-specific vocalizations. Previous studies have found multisensory neurons which respond to simultaneously presented faces and vocalizations in this region. Behavioral data suggests that face and vocal information are inextricably linke...

  1. Morphological Heterogeneity of Layer VI Neurons in Mouse Barrel Cortex

    OpenAIRE

    Chen, Chia-Chien; Abrams, Svetlana; Pinhas, Alex; Brumberg, Joshua C.

    2009-01-01

    Understanding the basic neuronal building blocks of the neocortex is a necessary first step toward comprehending the composition of cortical circuits. Neocortical layer VI is the most morphologically diverse layer and plays a pivotal role in gating information to the cortex via its feedback connection to the thalamus and other ipsilateral and callosal corticocortical connections. The heterogeneity of function within this layer is presumably linked to its varied morphological composition. Howe...

  2. Sparse representation of sounds in the unanesthetized auditory cortex.

    Directory of Open Access Journals (Sweden)

    Tomás Hromádka

    2008-01-01

    Full Text Available How do neuronal populations in the auditory cortex represent acoustic stimuli? Although sound-evoked neural responses in the anesthetized auditory cortex are mainly transient, recent experiments in the unanesthetized preparation have emphasized subpopulations with other response properties. To quantify the relative contributions of these different subpopulations in the awake preparation, we have estimated the representation of sounds across the neuronal population using a representative ensemble of stimuli. We used cell-attached recording with a glass electrode, a method for which single-unit isolation does not depend on neuronal activity, to quantify the fraction of neurons engaged by acoustic stimuli (tones, frequency modulated sweeps, white-noise bursts, and natural stimuli in the primary auditory cortex of awake head-fixed rats. We find that the population response is sparse, with stimuli typically eliciting high firing rates (>20 spikes/second in less than 5% of neurons at any instant. Some neurons had very low spontaneous firing rates (<0.01 spikes/second. At the other extreme, some neurons had driven rates in excess of 50 spikes/second. Interestingly, the overall population response was well described by a lognormal distribution, rather than the exponential distribution that is often reported. Our results represent, to our knowledge, the first quantitative evidence for sparse representations of sounds in the unanesthetized auditory cortex. Our results are compatible with a model in which most neurons are silent much of the time, and in which representations are composed of small dynamic subsets of highly active neurons.

  3. Orientation-tuned surround suppression in mouse visual cortex

    OpenAIRE

    Self, Matthew W.; Lorteije, Jeannette A. M.; Vangeneugden, Joris; van Beest, Enny H; Grigore, Mihaela E; Levelt, Christiaan N.; Heimel, J.A.; Roelfsema, Pieter R.

    2014-01-01

    The firing rates of neurons in primary visual cortex (V1) are suppressed by large stimuli, an effect known as surround suppression. In cats and monkeys, the strength of suppression is sensitive to orientation; responses to regions containing uniform orientations are more suppressed than those containing orientation contrast. This effect is thought to be important for scene segmentation, but the underlying neural mechanisms are poorly understood. We asked whether it is possible to study these ...

  4. "Visual" Cortex Responds to Spoken Language in Blind Children

    OpenAIRE

    Bedny, Marina; Richardson, Hilary; Saxe, Rebecca R.

    2015-01-01

    Plasticity in the visual cortex of blind individuals provides a rare window into the mechanisms of cortical specialization. In the absence of visual input, occipital (“visual”) brain regions respond to sound and spoken language. Here, we examined the time course and developmental mechanism of this plasticity in blind children. Nineteen blind and 40 sighted children and adolescents (4–17 years old) listened to stories and two auditory control conditions (unfamiliar foreign speech, and music). ...

  5. Decoding bipedal locomotion from the rat sensorimotor cortex

    Science.gov (United States)

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

    2015-10-01

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

  6. Anatomical Origins of Ocular Dominance in Mouse Primary Visual Cortex

    OpenAIRE

    Coleman, Jason E.; Law, Karen; Bear, Mark F.

    2009-01-01

    Ocular dominance (OD) plasticity is a classic paradigm for studying the effect of experience and deprivation on cortical development, and is manifested as shifts in the relative strength of binocular inputs to primary visual cortex (V1). The mouse has become an increasingly popular model for mechanistic studies of OD plasticity and, consequently, it is important that we understand how binocularity is constructed in this species. One puzzling feature of the mouse visual system is the gross dis...

  7. Flexible neural mechanisms of cognitive control within human prefrontal cortex

    OpenAIRE

    Braver, Todd S.; Paxton, Jessica L.; Locke, Hannah S.; Barch, Deanna M

    2009-01-01

    A major challenge in research on executive control is to reveal its functional decomposition into underlying neural mechanisms. A typical assumption is that this decomposition occurs solely through anatomically based dissociations. Here we tested an alternative hypothesis that different cognitive control processes may be implemented within the same brain regions, with fractionation and dissociation occurring on the basis of temporal dynamics. Regions within lateral prefrontal cortex (PFC) wer...

  8. Prefrontal Cortex, Emotion, and Approach/Withdrawal Motivation

    OpenAIRE

    Spielberg, Jeffrey M; Stewart, Jennifer L.; Levin, Rebecca L.; Miller, Gregory A.; Heller, Wendy

    2008-01-01

    This article provides a selective review of the literature and current theories regarding the role of prefrontal cortex, along with some other critical brain regions, in emotion and motivation. Seemingly contradictory findings have often appeared in this literature. Research attempting to resolve these contradictions has been the basis of new areas of growth and has led to more sophisticated understandings of emotional and motivational processes as well as neural networks associated with thes...

  9. Emergence of Complex Wave Patterns in Primate Cerebral Cortex

    OpenAIRE

    Townsend, Rory G.; Solomon, Selina S.; Chen, Spencer C.; Pietersen, Alexander N.J.; Martin, Paul R.; Solomon, Samuel G.; Gong, Pulin

    2015-01-01

    Slow brain rhythms are attributed to near-simultaneous (synchronous) changes in activity in neuron populations in the brain. Because they are slow and widespread, synchronous rhythms have not been considered crucial for information processing in the waking state. Here we adapted methods from turbulence physics to analyze δ-band (1–4 Hz) rhythms in local field potential (LFP) activity, in multielectrode recordings from cerebral cortex in anesthetized marmoset monkeys. We found that synchrony c...

  10. Adaptive filtering enhances information transmission in visual cortex

    OpenAIRE

    Sharpee, Tatyana O.; Sugihara, Hiroki; Kurgansky, Andrei V.; Rebrik, Sergei P.; Stryker, Michael P.; Miller, Kenneth D.

    2006-01-01

    Sensory neuroscience seeks to understand how the brain encodes natural environments. However, neural coding has largely been studied using simplified stimuli. In order to assess whether the brain’s coding strategy depends on the stimulus ensemble, we apply a new information-theoretic method that allows unbiased calculation of neural filters (receptive fields) from responses to natural scenes or other complex signals with strong multipoint correlations. In the cat primary visual cortex we comp...

  11. Development and Plasticity of the Primary Visual Cortex

    OpenAIRE

    Espinosa, J. Sebastian; Stryker, Michael P.

    2012-01-01

    Hubel and Wiesel began the modern study of development and plasticity of primary visual cortex (V1), discovering response properties of cortical neurons that distinguished them from their inputs and that were arranged in a functional architecture. Their findings revealed an early innate period of development and a later critical period of dramatic experience-dependent plasticity. Recent studies have used rodents to benefit from biochemistry and genetics. The roles of spontaneous neural activi...

  12. Distinct mechanisms for size tuning in primate visual cortex

    OpenAIRE

    Briggs, Farran; Usrey, W. Martin

    2011-01-01

    Most neurons in primary visual cortex (V1) are selective for stimulus size, a property with important implications for salient feature detection. Size selectivity involves dynamic interactions between neuronal circuits that establish the classical (center) and extraclassical (surround) of a neuron’s receptive field. Although much is known about the tuning properties and stimulus selectivity of the center and surround subunits, relatively little is known about how these subunits interact to ac...

  13. Is the Medial Prefrontal Cortex Necessary for Theory of Mind?

    OpenAIRE

    Otti, Alexander; Wohlschläger, Afra; Noll-Hussong, Michael

    2015-01-01

    Background: Successful social interaction relies on the ability to attribute mental states to other people. Previous functional neuroimaging studies have shown that this process, described as Theory of Mind (ToM) or mentalization, is reliably associated with activation of the medial prefrontal cortex (mPFC). However, this study presents a novel and surprising finding that provides new insight into the role of the mPFC in mentalization tasks. Methodology/Principal Findings: Twenty ...

  14. Prefrontal Cortex in Learning to Overcome Generalized Fear

    OpenAIRE

    Edward Korzus

    2015-01-01

    SUMMARY Normal brain functioning relies critically on the ability to control appropriate behavioral responses to fearful stimuli. Overgeneralized fear is the major symptom of anxiety disorders including posttraumatic stress disorder. This review describes recent data demonstrating that the medial prefrontal cortex (mPFC) plays a critical role in the refining of cues that drive the acquisition of fear response. Recent studies on molecular mechanisms that underlie the role of mPFC in fear discr...

  15. Structural and Functional Dichotomy of Human Midcingulate Cortex

    OpenAIRE

    Vogt, Brent A.; Berger, Gail R.; Derbyshire, Stuart W G

    2003-01-01

    Anterior cingulate cortex is comprised of perigenual and midcingulate regions based on cytology, imaging, and connections. Its anterior (aMCC) and posterior (pMCC) parts and transition to posterior area 23 were evaluated in 6 human cingulate gyri with Nissl-staining and immunoreactions for neuron-specific nuclear binding protein and intermediate neurofilament proteins (NFP) and their pain and emotion functions evaluated in standard coordinates. Morphological differences included a poorly diff...

  16. Behavioral Effects of Congenital Ventromedial Prefrontal Cortex Malformation

    OpenAIRE

    Boes Aaron D; Grafft Amanda; Joshi Charuta; Chuang Nathaniel A; Nopoulos Peg; Anderson Steven W

    2011-01-01

    Abstract Background A detailed behavioral profile associated with focal congenital malformation of the ventromedial prefrontal cortex (vmPFC) has not been reported previously. Here we describe a 14 year-old boy, B.W., with neurological and psychiatric sequelae stemming from focal cortical malformation of the left vmPFC. Case Presentation B.W.'s behavior has been characterized through extensive review Patience of clinical and personal records along with behavioral and neuropsychological testin...

  17. Principles underlying sensory map topography in primary visual cortex.

    Science.gov (United States)

    Kremkow, Jens; Jin, Jianzhong; Wang, Yushi; Alonso, Jose M

    2016-05-01

    The primary visual cortex contains a detailed map of the visual scene, which is represented according to multiple stimulus dimensions including spatial location, ocular dominance and stimulus orientation. The maps for spatial location and ocular dominance arise from the spatial arrangement of thalamic afferent axons in the cortex. However, the origins of the other maps remain unclear. Here we show that the cortical maps for orientation, direction and retinal disparity in the cat (Felis catus) are all strongly related to the organization of the map for spatial location of light (ON) and dark (OFF) stimuli, an organization that we show is OFF-dominated, OFF-centric and runs orthogonal to ocular dominance columns. Because this ON-OFF organization originates from the clustering of ON and OFF thalamic afferents in the visual cortex, we conclude that all main features of visual cortical topography, including orientation, direction and retinal disparity, follow a common organizing principle that arranges thalamic axons with similar retinotopy and ON-OFF polarity in neighbouring cortical regions. PMID:27120164

  18. Specialized Cortex Glial Cells Accumulate Lipid Droplets in Drosophila melanogaster.

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    Viktor Kis

    Full Text Available Lipid droplets (LDs are common organelles of the majority of eukaryotic cell types. Their biological significance has been extensively studied in mammalian liver cells and white adipose tissue. Although the central nervous system contains the highest relative amount and the largest number of different lipid species, neither the spatial nor the temporal distribution of LDs has been described. In this study, we used the brain of the fruitfly, Drosophila melanogaster, to investigate the neuroanatomy of LDs. We demonstrated that LDs are exclusively localised in glial cells but not in neurons in the larval nervous system. We showed that the brain's LD pool, rather than being constant, changes dynamically during development and reaches its highest value at the beginning of metamorphosis. LDs are particularly enriched in cortex glial cells located close to the brain surface. These specialized superficial cortex glial cells contain the highest amount of LDs among glial cell types and encapsulate neuroblasts and their daughter cells. Superficial cortex glial cells, combined with subperineurial glial cells, express the Drosophila fatty acid binding protein (Dfabp, as we have demonstrated through light- and electron microscopic immunocytochemistry. To the best of our best knowledge this is the first study that describes LD neuroanatomy in the Drosophila larval brain.

  19. Olfactory Predictive Codes and Stimulus Templates in Piriform Cortex

    Science.gov (United States)

    Zelano, Christina; Mohanty, Aprajita; Gottfried, Jay A.

    2011-01-01

    Summary Neuroscientific models of sensory perception suggest that the brain utilizes predictive codes in advance of a stimulus encounter, enabling organisms to infer forthcoming sensory events. However, it is poorly understood how such mechanisms are implemented in the olfactory system. Combining high-resolution functional magnetic resonance imaging with multivariate (pattern-based) analyses, we examined the spatiotemporal evolution of odor perception in the human brain during an olfactory search task. Ensemble activity patterns in anterior piriform cortex (APC) and orbitofrontal cortex (OFC) reflected the attended odor target both before and after stimulus onset. In contrast, pre-stimulus ensemble representations of the odor target in posterior piriform cortex (PPC) gave way to post-stimulus representations of the odor itself. Critically, the robustness of target-related patterns in PPC predicted subsequent behavioral performance. Our findings directly show that the brain generates predictive templates or “search images” in PPC, with physical correspondence to odor-specific pattern representations, to augment olfactory perception. PMID:21982378

  20. Brain polyphosphoinositide metabolism during focal ischemia in rat cortex

    International Nuclear Information System (INIS)

    Using a rat model of stroke, we examined the effects of focal cerebral ischemia on the metabolism of polyphosphoinositides by injecting 32Pi into both the left and right cortices. After equilibration of the label for 2-3 hours, ischemia induced a significant decrease (p less than 0.001) in the concentrations of labeled phosphatidyl 4,5-bisphosphates (66-78%) and phosphatidylinositol 4-phosphate (64-67%) in the right middle cerebral artery cortex of four rats. The phospholipid labeling pattern in the left middle cerebral artery cortex, which sustained only mild ischemia and no permanent tissue damage, was not different from that of two sham-operated controls. However, when 32Pi was injected 1 hour after the ischemic insult, there was a significant decrease (p less than 0.01) in the incorporation of label into the phospholipids in both cortices of four ischemic rats compared with four sham-operated controls. Furthermore, differences in the phospholipid labeling pattern were observed in the left cortex compared with the sham-operated controls. The change in labeling pattern was attributed to the partial reduction in blood flow following ligation of the common carotid arteries. We provide a sensitive procedure for probing the effects of focal cerebral ischemia on the polyphosphoinositide signaling pathway in the brain, which may play an important role in the pathogenesis of tissue injury

  1. Neural mechanisms of perceptual grouping in human visual cortex

    Institute of Scientific and Technical Information of China (English)

    MAO Lihua; HAN Shihui; GUO Chunyan; JIANG Yi

    2004-01-01

    The current work examined neural substrates of perceptual grouping in human visual cortex using event-related potential (ERP) recording. Stimulus arrays consisted of local elements that were either evenly spaced (uniform stimuli) or grouped into columns or rows by proximity or color similarity (grouping stimuli). High-density ERPs were recorded while subjects identified orientations of perceptual groups in stimulus arrays that were presented randomly in one of the four quadrants of the visual field. Both uniform and grouping stimulus arrays elicited an early ERP component (C1), which peaked at about 70 ms after stimulus onset and changed its polarity as a function of stimulated elevations. Dipole modeling based on realistic- head boundary-element models revealed generators of the C1 component in the calcarine cortex. The C1 was modulated by perceptual grouping of local elements based on proximity, and this grouping effect was stronger in the upper than in the lower visual field. The findings provide ERP evidence for the engagement of human primary visual cortex in the early stage of perceptual grouping.

  2. Ontogeny of somatostatin receptors in the rat somatosensory cortex

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, B.J.; Leroux, P.; Bodenant, C.; Vaudry, H. (Groupe de Recherche en Endocrinologie Moleculaire, CNRS URA 650, Unite Affiliee a l' INSERM, Mont-Saint-Aignan, (France))

    1991-03-08

    The distribution and density of SRIF receptors (SRIF-R) were studied during development in the rat somatosensory cortex by in vitro autoradiography with monoiodinated (Tyr0-DTrp8)S14. In 16-day-old fetuses (E16), intense labeling was evident in the intermediate zone of the cortex while low concentrations of SRIF-R were detected in the marginal and ventricular zones. The highest density of SRIF-R was measured in the intermediate zone at E18. At this stage, labeling was also intense in the internal part of the developing cortical plate; in contrast, the concentration of binding sites associated with the marginal and ventricular zones remained relatively low. Profound modifications in the distribution of SRIF-R appeared at birth. In particular, a transient reduction of receptor density occurred in the cortical plate. During the first postnatal week, the density of receptors measured in the intermediate zone decreased gradually; conversely, high levels of SRIF-R were observed in the developing cortical layers (II to VI). At postpartum day 13 (P13), a stage which just precedes completion of cell migration in the parietal cortex, the most intensely labeled regions were layers V-VI and future layers II-III. From P13 to adulthood, the concentrations of SRIF-R decreased in all cortical layers (I to VI) and the pattern of distribution of receptors at P21 was similar to that observed in the adults.

  3. Ontogeny of somatostatin receptors in the rat somatosensory cortex

    International Nuclear Information System (INIS)

    The distribution and density of SRIF receptors (SRIF-R) were studied during development in the rat somatosensory cortex by in vitro autoradiography with monoiodinated [Tyr0-DTrp8]S14. In 16-day-old fetuses (E16), intense labeling was evident in the intermediate zone of the cortex while low concentrations of SRIF-R were detected in the marginal and ventricular zones. The highest density of SRIF-R was measured in the intermediate zone at E18. At this stage, labeling was also intense in the internal part of the developing cortical plate; in contrast, the concentration of binding sites associated with the marginal and ventricular zones remained relatively low. Profound modifications in the distribution of SRIF-R appeared at birth. In particular, a transient reduction of receptor density occurred in the cortical plate. During the first postnatal week, the density of receptors measured in the intermediate zone decreased gradually; conversely, high levels of SRIF-R were observed in the developing cortical layers (II to VI). At postpartum day 13 (P13), a stage which just precedes completion of cell migration in the parietal cortex, the most intensely labeled regions were layers V-VI and future layers II-III. From P13 to adulthood, the concentrations of SRIF-R decreased in all cortical layers (I to VI) and the pattern of distribution of receptors at P21 was similar to that observed in the adults

  4. Remodeling of inhibitory synaptic connections in developing ferret visual cortex

    Directory of Open Access Journals (Sweden)

    Dalva Matthew B

    2010-02-01

    Full Text Available Abstract Background In the visual cortex, as in many other regions of the developing brain, excitatory synaptic connections undergo substantial remodeling during development. While evidence suggests that local inhibitory synapses may behave similarly, the extent and mechanisms that mediate remodeling of inhibitory connections are not well understood. Results Using scanning laser photostimulation in slices of developing ferret visual cortex, we assessed the overall patterns of developing inhibitory and excitatory synaptic connections converging onto individual neurons. Inhibitory synaptic inputs onto pyramidal neurons in cortical layers 2 and 3 were already present as early as postnatal day 20, well before eye opening, and originated from regions close to the recorded neurons. During the ensuing 2 weeks, the numbers of synaptic inputs increased, with the numbers of inhibitory (and excitatory synaptic inputs peaking near the time of eye opening. The pattern of inhibitory inputs refined rapidly prior to the refinement of excitatory inputs. By uncaging the neurotransmtter GABA in brain slices from animals of different ages, we find that this rapid refinement correlated with a loss of excitatory activity by GABA. Conclusion Inhibitory synapses, like excitatory synapses, undergo significant postnatal remodeling. The time course of the remodeling of inhibitory connections correlates with the emergence of orientation tuning in the visual cortex, implicating these rearrangements in the genesis of adult cortical response properties.

  5. The role of the midcingulate cortex in monitoring others’ decisions

    Directory of Open Access Journals (Sweden)

    Matthew A J Apps

    2013-12-01

    Full Text Available A plethora of research has implicated the cingulate cortex in the processing of social information (i.e. processing elicited by, about, and directed towards others and reward-related information that guides decision-making. However, it is often overlooked that there is variability in the cytoarchitectonic properties and anatomical connections across the cingulate cortex, which is indicative of functional variability. Here we review evidence from lesion, single-unit recording and functional imaging studies. Taken together, these support the claim that the processing of information that has the greatest influence on social behaviour can be localised to the gyral surface of the midcingulate cortex (MCCg. We propose that the MCCg is engaged when predicting and monitoring the outcomes of decisions during social interactions. In particular, the MCCg processes statistical information that tracks the extent to which the outcomes of decisions meet goals when interacting with others. We provide a novel framework for the computational mechanisms that underpin such social information processing in the MCCg. This framework provides testable hypotheses for the social deficits displayed in autism spectrum disorders and psychopathy.

  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. Engagement of right temporal cortex during processing of linguistic context.

    Science.gov (United States)

    Kircher, T T; Brammer, M; Tous Andreu, N; Williams, S C; McGuire, P K

    2001-01-01

    Language processing involves the interplay of areas in both cerebral hemispheres. Whereas the left temporal lobe is necessary for most language tasks, the right hemisphere seems to be additionally activated during processing of paragraphs and metaphors. We studied the neural correlates of word generation and selection in a sentence context, using functional magnetic resonance imaging (fMRI). Cerebral activation was measured while seven healthy, right handed volunteers read and completed sentence stems, with relatively low Cloze frequency, out loud. During a GENERATION condition, subjects were required to generate a word which completed a sentence stem appropriately. During a DECISION condition, subjects selected and articulated one of two presented terminal words. A READING condition in which subjects read an appropriate completion aloud, served as baseline. When GENERATION was compared to READING or DECISION, the left middle frontal, anterior cingulate, precuneus and right lateral temporal cortex were activated. During DECISION relative to READING, the left inferior frontal and middle/superior temporal cortex bilaterally were activated. The prominent engagement of the right lateral temporal cortex during the GENERATION conditions may reflect the processing of linguistic context, and particularly the activation of multiple meanings in the course of producing an appropriate completion. PMID:11369403

  8. On the origin of the functional architecture of the cortex.

    Directory of Open Access Journals (Sweden)

    Dario L Ringach

    Full Text Available The basic structure of receptive fields and functional maps in primary visual cortex is established without exposure to normal sensory experience and before the onset of the critical period. How the brain wires these circuits in the early stages of development remains unknown. Possible explanations include activity-dependent mechanisms driven by spontaneous activity in the retina and thalamus, and molecular guidance orchestrating thalamo-cortical connections on a fine spatial scale. Here I propose an alternative hypothesis: the blueprint for receptive fields, feature maps, and their inter-relationships may reside in the layout of the retinal ganglion cell mosaics along with a simple statistical connectivity scheme dictating the wiring between thalamus and cortex. The model is shown to account for a number of experimental findings, including the relationship between retinotopy, orientation maps, spatial frequency maps and cytochrome oxidase patches. The theory's simplicity, explanatory and predictive power makes it a serious candidate for the origin of the functional architecture of primary visual cortex.

  9. Intrahemispheric cortico-cortical connections of the human auditory cortex.

    Science.gov (United States)

    Cammoun, Leila; Thiran, Jean Philippe; Griffa, Alessandra; Meuli, Reto; Hagmann, Patric; Clarke, Stephanie

    2015-11-01

    The human auditory cortex comprises the supratemporal plane and large parts of the temporal and parietal convexities. We have investigated the relevant intrahemispheric cortico-cortical connections using in vivo DSI tractography combined with landmark-based registration, automatic cortical parcellation and whole-brain structural connection matrices in 20 right-handed male subjects. On the supratemporal plane, the pattern of connectivity was related to the architectonically defined early-stage auditory areas. It revealed a three-tier architecture characterized by a cascade of connections from the primary auditory cortex to six adjacent non-primary areas and from there to the superior temporal gyrus. Graph theory-driven analysis confirmed the cascade-like connectivity pattern and demonstrated a strong degree of segregation and hierarchy within early-stage auditory areas. Putative higher-order areas on the temporal and parietal convexities had more widely spread local connectivity and long-range connections with the prefrontal cortex; analysis of optimal community structure revealed five distinct modules in each hemisphere. The pattern of temporo-parieto-frontal connectivity was partially asymmetrical. In conclusion, the human early-stage auditory cortical connectivity, as revealed by in vivo DSI tractography, has strong similarities with that of non-human primates. The modular architecture and hemispheric asymmetry in higher-order regions is compatible with segregated processing streams and lateralization of cognitive functions. PMID:25173473

  10. Learning a New Selection Rule in Visual and Frontal Cortex.

    Science.gov (United States)

    van der Togt, Chris; Stănişor, Liviu; Pooresmaeili, Arezoo; Albantakis, Larissa; Deco, Gustavo; Roelfsema, Pieter R

    2016-08-01

    How do you make a decision if you do not know the rules of the game? Models of sensory decision-making suggest that choices are slow if evidence is weak, but they may only apply if the subject knows the task rules. Here, we asked how the learning of a new rule influences neuronal activity in the visual (area V1) and frontal cortex (area FEF) of monkeys. We devised a new icon-selection task. On each day, the monkeys saw 2 new icons (small pictures) and learned which one was relevant. We rewarded eye movements to a saccade target connected to the relevant icon with a curve. Neurons in visual and frontal cortex coded the monkey's choice, because the representation of the selected curve was enhanced. Learning delayed the neuronal selection signals and we uncovered the cause of this delay in V1, where learning to select the relevant icon caused an early suppression of surrounding image elements. These results demonstrate that the learning of a new rule causes a transition from fast and random decisions to a more considerate strategy that takes additional time and they reveal the contribution of visual and frontal cortex to the learning process. PMID:27269960

  11. Motor cortex stimulation therapy for post-stroke weakness

    International Nuclear Information System (INIS)

    Motor cortex stimulation (MCS) delivered concurrently with rehabilitation therapy may enhance motor recovery following stroke. We investigated the effects of MCS on the recovery from upper extremity paresis in patients with chronic stroke. In 12 patients who had moderate arm and finger paresis at more than 4 months after stroke, an electrode was placed through a small craniotomy on the epidural space of the motor cortex that was identified using functional MRI. MCS during occupational therapy for one hour was performed 3 times a day for at least 4 weeks. The mean scores for Fugl-Meyer assessments of the arm improved, from 37 preoperatively to 46 postoperatively. The mean grip strength improved from 3.25 to 9.0 kg. All patients appeared satisfactory in their results because they recognized an improvement of arm function. Although the mechanism of the beneficial effects of MCS on recovery after stroke has not been well known, the neuroplasticity might play a important role. In a few cases of the present series, it was observed that the hand motor cortex area detected on functional MRI had been enlarged after MCS therapy. MCS could become a novel neurosurgical treatment modality for the chronic post-stroke weakness. (author)

  12. Orbitofrontal cortex contribution to working memory. N-back ERP study

    International Nuclear Information System (INIS)

    Remarkable progress in cognitive neuroscience has revealed the involvement of the prefrontal cortex and the orbitofrontal cortex in human working memory, but the orbitofrontal cortex is still one of the least understood regions in the human brain. To elucidate the contribution of the orbitofrontal cortex to human working memory, we studied electroencephalography (EEG) P300 activity in n-back task. We elicited early P3 around 300 ms and late P3 around 360 ms of P300 components in n-back event related potentials (ERP). The amplitudes of the respective peaks changed depending on the working memory load (0-back, 1-back, 2-back, 3-back). We used source analysis to evaluate the orbitofrontal cortex in P3 components. A source model was constructed with the sources seeded from fMRI meta-analysis of n-back task and additional sources in the orbitofrontal cortex and the visual cortex estimated with P100 and late P3 components in the n-back ERP. This source model had more than 99% of GOF (goodness of fit) in n-back ERP. It gave us an insight of brain activity at the positions where sources existed. Early P3 was mainly produced by the dorsolateral prefrontal cortex, the ventrolateral prefrontal cortex, the inferior parietal lobule, the medial posterior parietal and the visual cortex. Late P3 was mainly produced by the medial premotor, the lateral premotor, the frontal pole and the orbitofrontal cortex. The contribution of the frontal pole and the orbitofrontal cortex had peaks around 390 ms which were later than late P3 component. In this study, the method to evaluate the orbitofrontal cortex activity in n-back ERP was provided. Our results elicited the involvement of the orbitofrontal cortex in late P3 component of n-back ERP. (author)

  13. Medial profrontal cortex and anterior cingulate cortex in the generation of alpha activity induced by transcendental meditation: a magnetoencephalographic study.

    Directory of Open Access Journals (Sweden)

    Yamamoto,Shin

    2006-02-01

    Full Text Available

    Previous EEG studies have shown that transcendental meditation (TM increases frontal and central alpha activity. The present study was aimed at identifying the source of this alpha activity using magnetoencephalography (MEG and electroencephalography (EEG simultaneously on eight TM practitioners before, during, and after TM. The magnetic field potentials corresponding to TM-induced alpha activities on EEG recordings were extracted, and we attempted to localize the dipole sources using the multiple signal classification (MUSIC algorithm, equivalent current dipole source analysis, and the multiple spatio-temporal dipole model. Since the dipoles were mapped to both the medial prefrontal cortex (mPFC and anterior cingulate cortex (ACC, it is suggested that the mPFC and ACC play an important role in brain activity induced by TM.

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

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    Joshua G.A Pinto

    2015-02-01

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

  15. A change in injured corticospinal tract originating from the premotor cortex to the primary motor cortex in a patient with intracerebral hemorrhage

    Institute of Scientific and Technical Information of China (English)

    Sang Seok Yeo; Sung Ho Jang

    2012-01-01

    Many studies have attempted to elucidate the motor recovery mechanism of stroke, but the majority of these studies focus on cerebral infarct and relatively little is known about the motor recovery mechanism of intracerebral hemorrhage. In this study, we report on a patient with intracerebral hemorrhage who displayed a change in injured corticospinal tract originating from the premotor cortex to the primary motor cortex on diffusion tensor imaging. An 86-year-old woman presented with complete paralysis of the right extremities following spontaneous intracerebral hemorrhage in the left frontoparietal cortex. The patient showed motor recovery, to the extent of being able to extend affected fingers against gravity and to walk independently on even ground at 5 months after onset. Diffusion tensor imaging showed that the left corticospinal tract originated from the premotor cortex at 1 month after intracerebral hemorrhage and from the left primary motor cortex and premotor cortex at 5 months after intracerebral hemorrhage. The change of injured corticospinal tract originating from the premotor cortex to the primary motor cortex suggests motor recovery of intracerebral hemorrhage.

  16. Decoding individual natural scene representations during perception and imagery

    Directory of Open Access Journals (Sweden)

    Matthew Robert Johnson

    2014-02-01

    Full Text Available We used a multi-voxel classification analysis of functional magnetic resonance imaging (fMRI data to determine to what extent item-specific information about complex natural scenes is represented in several category-selective areas of human extrastriate visual cortex during visual perception and visual mental imagery. Participants in the scanner either viewed or were instructed to visualize previously memorized natural scene exemplars, and the neuroimaging data were subsequently subjected to a multi-voxel pattern analysis (MVPA using a support vector machine (SVM classifier. We found that item-specific information was represented in multiple scene-selective areas: the occipital place area (OPA, parahippocampal place area (PPA, retrosplenial cortex (RSC, and a scene-selective portion of the precuneus/intraparietal sulcus region (PCu/IPS. Furthermore, item-specific information from perceived scenes was re-instantiated during mental imagery of the same scenes. These results support findings from previous decoding analyses for other types of visual information and/or brain areas during imagery or working memory, and extend them to the case of visual scenes (and scene-selective cortex. Taken together, such findings support models suggesting that reflective mental processes are subserved by the re-instantiation of perceptual information in high-level visual cortex. We also examined activity in the fusiform face area (FFA and found that it, too, contained significant item-specific scene information during perception, but not during mental imagery. This suggests that although decodable scene-relevant activity occurs in FFA during perception, FFA activity may not be a necessary (or even relevant component of one’s mental representation of visual scenes.

  17. Altered functional connectivity of the insular cortex across prefrontal networks in cocaine addiction.

    Science.gov (United States)

    Cisler, Josh M; Elton, Amanda; Kennedy, Ashley P; Young, Jonathan; Smitherman, Sonet; Andrew James, George; Kilts, Clinton D

    2013-07-30

    Interoception is theorized to be an important process mediating substance use disorders, and the insular cortex is recognized as a core neural region supporting interoception. The purpose of this study was to compare the integration of the insular cortex into prefrontal-related resting-state networks between individuals with cocaine dependence and healthy controls. Participants comprised 41 patients with cocaine dependence and 19 controls who underwent a resting-state 3-T functional magnetic resonance imaging scan. Individuals with cocaine dependence demonstrated altered functional connectivity of the insular cortex, predominantly the right insular cortex, with all eight prefrontal-related resting-state networks identified through Independent Component Analysis (ICA). A conjunction analysis demonstrated that the right insular cortex was the neural region with the highest number of common group differences across the networks. There was no evidence that insular cortex connectivity commonly differed between groups for non-prefrontal-related networks. Further, seed-based functional connectivity analyses extended the network analyses and indicated that cocaine dependence was associated with greater connectivity of the right insula with the dorsomedial prefrontal cortex, inferior frontal gyrus, and bilateral dorsolateral prefrontal cortex. These data support the hypothesis that cocaine dependence is related to altered functional interactions of the insular cortex with prefrontal networks. The results suggest possible neural mechanisms by which the insular cortex and interoceptive information influence cognitive control and decision-making processes presumably mediated by prefrontal networks in the cocaine dependence process. PMID:23684980

  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. Sexually Monomorphic Maps and Dimorphic Responses in Rat Genital Cortex.

    Science.gov (United States)

    Lenschow, Constanze; Copley, Sean; Gardiner, Jayne M; Talbot, Zoe N; Vitenzon, Ariel; Brecht, Michael

    2016-01-11

    Mammalian external genitals show sexual dimorphism [1, 2] and can change size and shape upon sexual arousal. Genitals feature prominently in the oldest pieces of figural art [3] and phallic depictions of penises informed psychoanalytic thought about sexuality [4, 5]. Despite this longstanding interest, the neural representations of genitals are still poorly understood [6]. In somatosensory cortex specifically, many studies did not detect any cortical representation of genitals [7-9]. Studies in humans debate whether genitals are represented displaced below the foot of the cortical body map [10-12] or whether they are represented somatotopically [13-15]. We wondered what a high-resolution mapping of genital representations might tell us about the sexual differentiation of the mammalian brain. We identified genital responses in rat somatosensory cortex in a region previously assigned as arm/leg cortex. Genital responses were more common in males than in females. Despite such response dimorphism, we observed a stunning anatomical monomorphism of cortical penis and clitoris input maps revealed by cytochrome-oxidase-staining of cortical layer 4. Genital representations were somatotopic and bilaterally symmetric, and their relative size increased markedly during puberty. Size, shape, and erect posture give the cortical penis representation a phallic appearance pointing to a role in sexually aroused states. Cortical genital neurons showed unusual multi-body-part responses and sexually dimorphic receptive fields. Specifically, genital neurons were co-activated by distant body regions, which are touched during mounting in the respective sex. Genital maps indicate a deep homology of penis and clitoris representations in line with a fundamentally bi-sexual layout [16] of the vertebrate brain. PMID:26725197

  20. Circadian rhythmicity of synapses in mouse somatosensory cortex.

    Science.gov (United States)

    Jasinska, Malgorzata; Grzegorczyk, Anna; Woznicka, Olga; Jasek, Ewa; Kossut, Malgorzata; Barbacka-Surowiak, Grazyna; Litwin, Jan A; Pyza, Elzbieta

    2015-10-01

    The circadian rhythmicity displayed by motor behavior of mice: activity at night and rest during the day; and the associated changes in the sensory input are reflected by cyclic synaptic plasticity in the whisker representations located in the somatosensory (barrel) cortex. It was not clear whether diurnal rhythmic changes in synapse density previously observed in the barrel cortex resulted from changes in the activity of the animals, from daily light/dark (LD) rhythm or are driven by an endogenous clock. These changes were investigated in the barrel cortex of C57BL/6 mouse strain kept under LD 12 : 12 h conditions and in constant darkness (DD). Stereological analysis of serial electron microscopic sections was used to assess numerical density of synapses. In mice kept under LD conditions, the total density of synapses and the density of excitatory synapses located on dendritic spines was higher during the light period (rest phase). In contrast, the density of inhibitory synapses located on dendritic spines increased during the dark period (activity phase). Under DD conditions, the upregulation of the inhibitory synapses during the activity phase was retained, but the cyclic changes in the density of excitatory synapses were not observed. The results show that the circadian plasticity concerns only synapses located on spines (and not those on dendritic shafts), and that excitatory and inhibitory synapses are differently regulated during the 24 h cycle: the excitatory synapses are influenced by light, whilst the inhibitory synapses are driven by the endogenous circadian clock. PMID:26274013

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

    Directory of Open Access Journals (Sweden)

    Danilo eBzdok

    2013-05-01

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

  2. A disinhibitory microcircuit initiates critical period plasticity in visual cortex

    Science.gov (United States)

    Kuhlman, Sandra J.; Olivas, Nicholas D.; Tring, Elaine; Ikrar, Taruna; Xu, Xiangmin; Trachtenberg, Joshua T.

    2014-01-01

    Early sensory experience instructs the maturation of neural circuitry in cortex 1,2. This has been extensively studied in the primary visual cortex where loss of vision to one eye permanently degrades cortical responsiveness to that eye 3,4, a phenomenon known as ocular dominance plasticity (ODP). Cortical inhibition mediates this process 4-6, but the precise role of specific classes of inhibitory neurons in ODP is controversial. Here we report that evoked firing rates of binocular excitatory neurons in primary visual cortex immediately drop by half when vision is restricted to one eye, but gradually return to normal over the following 24 hours, despite the fact that vision remains restricted to one eye. This restoration of binocular-like excitatory firing rates following monocular deprivation results from a rapid, though transient reduction in the firing rates of fast-spiking, parvalbumin-positive (PV) interneurons, which in turn can be attributed to a decrease in local excitatory circuit input onto PV interneurons. This reduction in PV cell evoked responses following monocular lid suture is restricted to the critical period for ODP and appears to be necessary for subsequent shifts in excitatory ODP. Pharmacologically enhancing inhibition at the time of sight deprivation blocks ODP and, conversely, pharmaco-genetic reduction of PV cell firing rates can extend the critical period for ODP. These findings define the microcircuit changes initiating competitive plasticity during critical periods of cortical development. Moreover, they show that the restoration of evoked firing rates of L2/3 pyramidal neurons by PV-specific disinhibition is a key step in the progression of ocular dominance plasticity. PMID:23975100

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

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    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

  4. Quantification of the adrenal cortex hormones with radioimmunoassay

    International Nuclear Information System (INIS)

    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 α-OH-PRG and of the DHEA-SO4 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)

  5. The neural representation of Arabic digits in visual cortex

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    Lien ePeters

    2015-09-01

    Full Text Available In this study, we investigated how Arabic digits are represented in the visual cortex, and how their representation changes throughout the ventral visual processing stream, compared to the representation of letters. We probed these questions with two fMRI experiments. In Experiment 1, we explored whether we could find brain regions that were more activated for digits than for number words in a subtraction task. One such region was detected in lateral occipital cortex. However, the activity in this region might have been confounded by string length – number words contain more characters than digits. We therefore conducted a second experiment in which string length was systematically controlled. Experiment 2 revealed that the findings of the first experiment were task dependent (as it was only observed in a task in which numerosity was relevant or stimulus dependent (as it was only observed when the number of characters of a stimulus was not controlled.We further explored the characteristics of the activation patterns for digit and letter strings across the ventral visual processing stream through multi-voxel pattern analyses. We found an alteration in representations throughout the ventral processing stream from clustering based on amount of visual information in primary visual cortex towards clustering based on symbolic stimulus category higher in the visual hierarchy. The present findings converge to the conclusion that in the ventral visual system, as far as can be detected with fMRI, the distinction between Arabic digits and letter strings is represented in terms of distributed patterns rather than separate regions.

  6. 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...... 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...... 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...

  7. GABAergic synapses: their plasticity and role in sensory cortex

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    Trevor C Griffen

    2014-03-01

    Full Text Available The mammalian neocortex is composed of a variety of cell types organized in a highly interconnected circuit. GABAergic neurons account for only about 20% of cortical neurons. However, they show widespread connectivity and a high degree of diversity in morphology, location, electrophysiological properties and gene expression. In addition, distinct populations of inhibitory neurons have different sensory response properties, capacities for plasticity and sensitivities to changes in sensory experience. In this review we summarize experimental evidence regarding the properties of GABAergic neurons in primary sensory cortex. We will discuss how distinct GABAergic neurons and different forms of GABAergic inhibitory plasticity may contribute to shaping sensory cortical circuit activity and function.

  8. Images of Illusory Motion in Primary Visual Cortex

    DEFF Research Database (Denmark)

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

    2006-01-01

    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 is...

  9. Neural Correlates of an Auditory Afterimage in Primary Auditory Cortex

    OpenAIRE

    Noreña, A. J.; Eggermont, J. J.

    2003-01-01

    The Zwicker tone (ZT) is defined as an auditory negative afterimage, perceived after the presentation of an appropriate inducer. Typically, a notched noise (NN) with a notch width of 1/2 octave induces a ZT with a pitch falling in the frequency range of the notch. The aim of the present study was to find potential neural correlates of the ZT in the primary auditory cortex of ketamine-anesthetized cats. Responses of multiunits were recorded simultaneously with two 8-electrode arrays during 1 s...

  10. Multiple subpial cortical transections for the control of intractable epilepsy in exquisite cortex.

    Science.gov (United States)

    Dogali, M; Devinsky, O; Luciano, D; Perrine, K; Beric, A

    1993-01-01

    In 5 cases suffering from intractable seizures and ictal onset in exquisite (primary somatosensory or language related) cortex, surgical therapy has been done consisting wholly or in part of multiple subpial transections. In two cases with involvement of the primary somatosensory cortex, good seizure control without detectable neurological deficit was achieved. In the other three cases with involvement of the language cortex, deficits were minimal and cleared with time. Patients became seizure-free. PMID:8109292

  11. High familial risk for mood disorder is associated with low dorsolateral prefrontal cortex serotonin transporter binding

    DEFF Research Database (Denmark)

    Frokjaer, Vibe G; Vinberg, Maj; Erritzoe, David;

    2009-01-01

    Mood disorders are elicited through a combination of genetic and environmental stress factors, and treatment with selective serotonin reuptake inhibitors ameliorates depressive symptoms. Changes in the serotonin transporter (SERT) binding may therefore occur in depressive patients and in subjects...... measured with [(11)C]DASB PET. The volumes of interest included the orbitofrontal cortex, the dorsolateral prefrontal cortex, the ventrolateral prefrontal cortex, anterior cingulate, caudate, putamen, thalamus, and midbrain. We found that individuals at high familial risk for mood disorders had a 35...

  12. Sleep-active cells in the cerebral cortex and their role in slow-wave activity

    OpenAIRE

    Gerashchenko, Dmitry; Wisor, Jonathan P.; Kilduff, Thomas S.

    2011-01-01

    We recently identified neurons in the cerebral cortex that become activated during sleep episodes with high slow-wave activity (SWA). The distinctive properties of these neurons are the ability to produce nitric oxide and their long-range projections within the cortex. In this review, we discuss how these characteristics of sleep-active cells could be relevant to SWA production in the cortex. We also discuss possible models of the role of nNOS cells in SWA production.

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

    OpenAIRE

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

    2013-01-01

    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 ...

  14. Differential visually-induced gamma-oscillations in human cerebral cortex

    OpenAIRE

    Asano, Eishi; Nishida, Masaaki; Fukuda, Miho; Rothermel, Robert; Juhasz, Csaba; Sood, Sandeep

    2008-01-01

    Using intracranial electrocorticography, we determined how cortical gamma-oscillations (50–150Hz) were induced by different visual tasks in nine children with focal epilepsy. In all children, full-field stroboscopic flash-stimuli induced gamma-augmentation in the anterior-medial occipital cortex (starting on average at 31-msec after stimulus presentation) and subsequently in the lateral-polar occipital cortex; minimal gamma-augmentation was noted in the inferior occipital-temporal cortex; occ...

  15. The Prelimbic Cortex and Subthalamic Nucleus Contribute to Cue-Guided Behavioral Switching

    OpenAIRE

    Baker, Phillip M.; Ragozzino, Michael E.

    2013-01-01

    Frontal cortex - basal ganglia circuitry supports behavioral switching when a change in outcome information is used to adapt response patterns. Less is known about whether specific frontal cortex-basal ganglia circuitry supports behavioral switching when cues signal that a change in response patterns should occur. The present experiments investigated whether the prelimbic cortex and subthalamic nucleus in male Long-Evans rats supports cue-guided switching in a conditional discrimination test....

  16. AUDITORY CORTICAL PLASTICITY: DOES IT PROVIDE EVIDENCE FOR COGNITIVE PROCESSING IN THE AUDITORY CORTEX?

    OpenAIRE

    Irvine, Dexter R. F.

    2007-01-01

    The past 20 years have seen substantial changes in our view of the nature of the processing carried out in auditory cortex. Some processing of a cognitive nature, previously attributed to higher order “association” areas, is now considered to take place in auditory cortex itself. One argument adduced in support of this view is the evidence indicating a remarkable degree of plasticity in the auditory cortex of adult animals. Such plasticity has been demonstrated in a wide range of paradigms, i...

  17. A Spiking Neural Network Based Cortex-Like Mechanism and Application to Facial Expression Recognition

    OpenAIRE

    Si-Yao Fu; Guo-Sheng Yang; Xin-Kai Kuai

    2012-01-01

    In this paper, we present a quantitative, highly structured cortex-simulated model, which can be simply described as feedforward, hierarchical simulation of ventral stream of visual cortex using biologically plausible, computationally convenient spiking neural network system. The motivation comes directly from recent pioneering works on detailed functional decomposition analysis of the feedforward pathway of the ventral stream of visual cortex and developments on artificial spiking neural net...

  18. Fine functional organization of auditory cortex revealed by Fourier optical imaging

    OpenAIRE

    Kalatsky, Valery A.; Polley, Daniel B.; Merzenich, Michael M.; Schreiner, Christoph E.; Stryker, Michael P.

    2005-01-01

    We provide an overall view of the functional tonotopic organization of the auditory cortex in the rat. We apply a recently developed technique for acquiring intrinsic signal optical maps, Fourier imaging, in the rat auditory cortex. These highly detailed maps, derived in a several-minute-long recording procedure, delineate multiple auditory cortical areas and demonstrate their shapes, sizes, and tonotopic order. Beyond the primary auditory cortex, there are at least three distinct areas with ...

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

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    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.

  20. Dopaminergic Modulation of Medial Prefrontal Cortex Deactivation in Parkinson Depression

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    Anders H. Andersen

    2015-01-01

    Full Text Available Parkinson’s disease (PD is associated with emotional abnormalities. Dopaminergic medications ameliorate Parkinsonian motor symptoms, but less is known regarding the impact of dopaminergic agents on affective processing, particularly in depressed PD (dPD patients. The aim of this study was to examine the effects of dopaminergic pharmacotherapy on brain activation to emotional stimuli in depressed versus nondepressed Parkinson disease (ndPD patients. Participants included 18 ndPD patients (11 men, 7 women and 10 dPD patients (7 men, 3 women. Patients viewed photographs of emotional faces during functional MRI. Scans were performed while the patient was taking anti-Parkinson medication and the day after medication had been temporarily discontinued. Results indicate that dopaminergic medications have opposite effects in the prefrontal cortex depending upon depression status. DPD patients show greater deactivation in the ventromedial prefrontal cortex (VMPFC on dopaminergic medications than off, while ndPD patients show greater deactivation in this region off drugs. The VMPFC is in the default-mode network (DMN. DMN activity is negatively correlated with activity in brain systems used for external visual attention. Thus dopaminergic medications may promote increased attention to external visual stimuli among dPD patients but impede normal suppression of DMN activity during external stimulation among ndPD patients.

  1. Dopaminergic Modulation of Medial Prefrontal Cortex Deactivation in Parkinson Depression.

    Science.gov (United States)

    Andersen, Anders H; Smith, Charles D; Slevin, John T; Kryscio, Richard J; Martin, Catherine A; Schmitt, Frederick A; Blonder, Lee X

    2015-01-01

    Parkinson's disease (PD) is associated with emotional abnormalities. Dopaminergic medications ameliorate Parkinsonian motor symptoms, but less is known regarding the impact of dopaminergic agents on affective processing, particularly in depressed PD (dPD) patients. The aim of this study was to examine the effects of dopaminergic pharmacotherapy on brain activation to emotional stimuli in depressed versus nondepressed Parkinson disease (ndPD) patients. Participants included 18 ndPD patients (11 men, 7 women) and 10 dPD patients (7 men, 3 women). Patients viewed photographs of emotional faces during functional MRI. Scans were performed while the patient was taking anti-Parkinson medication and the day after medication had been temporarily discontinued. Results indicate that dopaminergic medications have opposite effects in the prefrontal cortex depending upon depression status. DPD patients show greater deactivation in the ventromedial prefrontal cortex (VMPFC) on dopaminergic medications than off, while ndPD patients show greater deactivation in this region off drugs. The VMPFC is in the default-mode network (DMN). DMN activity is negatively correlated with activity in brain systems used for external visual attention. Thus dopaminergic medications may promote increased attention to external visual stimuli among dPD patients but impede normal suppression of DMN activity during external stimulation among ndPD patients. PMID:26793404

  2. Prefrontal cortex and social cognition in mouse and man

    Directory of Open Access Journals (Sweden)

    Lucy King Bicks

    2015-11-01

    Full Text Available Social cognition is a complex process that requires the integration of a wide variety of behaviors, including salience, reward-seeking, motivation, knowledge of self and others, and flexibly adjusting behavior in social groups. Not surprisingly, social cognition represents a sensitive domain commonly disrupted in the pathology of a variety of psychiatric disorders including Autism Spectrum Disorder (ASD and Schizophrenia (SCZ. Here, we discuss convergent research from animal models to human disease that implicates the prefrontal cortex (PFC as a key regulator in social cognition, suggesting that disruptions in prefrontal microcircuitry play an essential role in the pathophysiology of psychiatric disorders with shared social deficits. We take a translational perspective of social cognition, and review three key behaviors that are essential to normal social processing in rodents and humans, including social motivation, social recognition, and dominance hierarchy. A shared prefrontal circuitry may underlie these behaviors. Social cognition deficits in animal models of neurodevelopmental disorders like ASD and SCZ have been linked to an altered balance of excitation and inhibition (E/I ratio within the cortex generally, and PFC specifically. A clear picture of the mechanisms by which altered E/I ratio in the PFC might lead to disruptions of social cognition across a variety of behaviors is not well understood. Future studies should explore how disrupted developmental trajectory of prefrontal microcircuitry could lead to altered E/I balance and subsequent deficits in the social domain

  3. The ventral pallidum and orbitofrontal cortex support food pleasantness inferences.

    Science.gov (United States)

    Simmons, W Kyle; Rapuano, Kristina M; Ingeholm, John E; Avery, Jason; Kallman, Seth; Hall, Kevin D; Martin, Alex

    2014-03-01

    Food advertisements often promote choices that are driven by inferences about the hedonic pleasures of eating a particular food. Given the individual and public health consequences of obesity, it is critical to address unanswered questions about the specific neural systems underlying these hedonic inferences. For example, although regions such as the orbitofrontal cortex (OFC) are frequently observed to respond more to pleasant food images than less hedonically pleasing stimuli, one important hedonic brain region in particular has largely remained conspicuously absent among human studies of hedonic response to food images. Based on rodent research demonstrating that activity in the ventral pallidum underlies the hedonic pleasures experienced upon eating food rewards, one might expect that activity in this important 'hedonic hotspot' might also track inferred food pleasantness. To date, however, no human studies have assessed this question. We thus asked human subjects to undergo fMRI and make item-by-item ratings of how pleasant it would be to eat particular visually perceived foods. Activity in the ventral pallidum was strongly modulated with pleasantness inferences. Additionally, activity within a region of the orbitofrontal cortex that tracks the pleasantness of tastes was also modulated with inferred pleasantness. Importantly, the reliability of these findings is demonstrated by their replication when we repeated the experiment at a new site with new subjects. These two experiments demonstrate that the ventral pallidum, in addition to the OFC, plays a central role in the moment-to-moment hedonic inferences that influence food-related decision-making. PMID:23397317

  4. Characterization of Face-Selective Patches in Orbitofrontal Cortex

    Science.gov (United States)

    Troiani, Vanessa; Dougherty, Chase C.; Michael, Andrew M.; Olson, Ingrid R.

    2016-01-01

    Face processing involves a complex, multimodal brain network. While visual-perceptual face patches in posterior parts of the brain have been studied for over a decade, the existence and properties of face-selective regions in orbitofrontal cortex (OFC) is a relatively new area of research. While regions of OFC are implicated in the emotional processing of faces, this is typically interpreted as a domain-general response to affective value rather than a face- or socially-specific response. However, electrophysiology studies in monkeys have identified neurons in OFC that respond more to faces than any other stimuli. Here, we characterize the prevalence and location of OFC face-selective regions in 20 healthy college students. We did this by including another biologically motivating category (appetizing foods) in a variant of the standard face localizer. Results show that face-selective patches can be identified at the individual level. Furthermore, in both a region of interest (ROI) and a whole brain analysis, medial regions of the OFC were face-selective, while lateral regions were responsive to faces and foods, indicating a domain-general response in lateral OFC. Medial OFC (mOFC) response to faces scales in relationship to a measure of social motivation that is distinct from face processing abilities associated with fusiform cortex. PMID:27378880

  5. Triglycerides in the human kidney cortex: relationship with body size.

    Directory of Open Access Journals (Sweden)

    Ion Alexandru Bobulescu

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

  6. Cochlear injury and adaptive plasticity of the auditory cortex

    Directory of Open Access Journals (Sweden)

    ANNA R. eFETONI

    2015-02-01

    Full Text Available Growing evidence suggests that cochlear stressors as noise exposure and aging can induce homeostatic/maladaptive changes in the central auditory system from the brainstem to the cortex. Studies centered on such changes have revealed several mechanisms that operate in the context of sensory disruption after insult (noise trauma, drug- or age-related injury. The oxidative stress is central to current theories of induced sensory neural hearing loss and aging, and interventions to attenuate the hearing loss are based on antioxidant agent. The present review addresses the recent literature on the alterations in hair cells and spiral ganglion neurons due to noise-induced oxidative stress in the cochlea, as well on the impact of cochlear damage on the auditory cortex neurons. The emerging image emphasizes that noise-induced deafferentation and upward spread of cochlear damage is associated with the altered dendritic architecture of auditory pyramidal neurons. The cortical modifications may be reversed by treatment with antioxidants counteracting the cochlear redox imbalance. These findings open new therapeutic approaches to treat the functional consequences of the cortical reorganization following cochlear damage.

  7. Ventromedial prefrontal cortex, adding value to autobiographical memories.

    Science.gov (United States)

    Lin, Wen-Jing; Horner, Aidan J; Burgess, Neil

    2016-01-01

    The medial prefrontal cortex (mPFC) has been consistently implicated in autobiographical memory recall and decision making. Its function in decision making tasks is believed to relate to value representation, but its function in autobiographical memory recall is not yet clear. We hypothesised that the mPFC represents the subjective value of elements during autobiographical memory retrieval. Using functional magnetic resonance imaging during an autobiographical memory recall task, we found that the blood oxygen level dependent (BOLD) signal in ventromedial prefrontal cortex (vmPFC) was parametrically modulated by the affective values of items in participants' memories when they were recalling and evaluating these items. An unrelated modulation by the participant's familiarity with the items was also observed. During retrieval of the event, the BOLD signal in the same region was modulated by the personal significance and emotional intensity of the memory, which was correlated with the values of the items within them. These results support the idea that vmPFC processes self-relevant information, and suggest that it is involved in representing the personal emotional values of the elements comprising autobiographical memories. PMID:27338616

  8. Frontal cortex functioning in the infant broader autism phenotype.

    Science.gov (United States)

    Holmboe, Karla; Elsabbagh, Mayada; Volein, Agnes; Tucker, Leslie A; Baron-Cohen, Simon; Bolton, Patrick; Charman, Tony; Johnson, Mark H

    2010-12-01

    Atypical attention has been proposed as a marker of the broader autism phenotype. In the present study we investigated this and the related process of inhibitory control at the youngest possible age through the study of infant siblings of children with an autism spectrum disorder (Sibs-ASD). Both attention and inhibition have been related to the frontal cortex of the brain. Nine- to ten-month-old Sibs-ASD and low-risk control infants completed the Freeze-Frame task, in which infants are encouraged to inhibit looks to peripherally presented distractors whilst looking at a central animation. The attractiveness of the central stimulus is varied in order to investigate the selectivity of infants' responses. In line with previous studies, it was found that a subset of Sibs-ASD infants had difficulty disengaging attention from a central stimulus in order to orient to a peripheral stimulus. The Sibs-ASD group also showed less Selective Inhibition than controls. However, Sibs-ASD infants did demonstrate Selective Inhibitory Learning. These results provide preliminary evidence for atypical frontal cortex functioning in the infant broader autism phenotype. PMID:20609478

  9. 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. PMID:26098331

  10. Higher Order Spike Synchrony in Prefrontal Cortex during Visual Memory.

    Science.gov (United States)

    Pipa, Gordon; Munk, Matthias H J

    2011-01-01

    Precise temporal synchrony of spike firing has been postulated as an important neuronal mechanism for signal integration and the induction of plasticity in neocortex. As prefrontal cortex plays an important role in organizing memory and executive functions, the convergence of multiple visual pathways onto PFC predicts that neurons should preferentially synchronize their spiking when stimulus information is processed. Furthermore, synchronous spike firing should intensify if memory processes require the induction of neuronal plasticity, even if this is only for short-term. Here we show with multiple simultaneously recorded units in ventral prefrontal cortex that neurons participate in 3 ms precise synchronous discharges distributed across multiple sites separated by at least 500 μm. The frequency of synchronous firing is modulated by behavioral performance and is specific for the memorized visual stimuli. In particular, during the memory period in which activity is not stimulus driven, larger groups of up to seven sites exhibit performance dependent modulation of their spike synchronization. PMID:21713065

  11. Cochlear injury and adaptive plasticity of the auditory cortex.

    Science.gov (United States)

    Fetoni, Anna Rita; Troiani, Diana; Petrosini, Laura; Paludetti, Gaetano

    2015-01-01

    Growing evidence suggests that cochlear stressors as noise exposure and aging can induce homeostatic/maladaptive changes in the central auditory system from the brainstem to the cortex. Studies centered on such changes have revealed several mechanisms that operate in the context of sensory disruption after insult (noise trauma, drug-, or age-related injury). The oxidative stress is central to current theories of induced sensory-neural hearing loss and aging, and interventions to attenuate the hearing loss are based on antioxidant agent. The present review addresses the recent literature on the alterations in hair cells and spiral ganglion neurons due to noise-induced oxidative stress in the cochlea, as well on the impact of cochlear damage on the auditory cortex neurons. The emerging image emphasizes that noise-induced deafferentation and upward spread of cochlear damage is associated with the altered dendritic architecture of auditory pyramidal neurons. The cortical modifications may be reversed by treatment with antioxidants counteracting the cochlear redox imbalance. These findings open new therapeutic approaches to treat the functional consequences of the cortical reorganization following cochlear damage. PMID:25698966

  12. Cadmium and zinc relationships in kidney cortex, liver, and pancreas

    Energy Technology Data Exchange (ETDEWEB)

    Elinder, C.G.; Piscator, M.; Linnman, L.

    1977-06-01

    Zinc and cadmium have been determined in kidney cortex, liver, and pancreas from 292 subjects autopsied in Stockholm, Sweden. In the liver and pancreas zinc was found to have a normal frequency distribution, average 45.3 ..mu..g/g and 26.9 ..mu..g/g wet wt, respectively. The concentrations of zinc in these two organs were constant regardless of age at death. Zinc was shown to accumulate with age in the kidney cortex in a way similar to cadmium, and had a log-normal distribution. The calculation of the regression line between individual cadmium concentrations below 60 ..mu..g/g and zinc concentrations gave a slope constant of 0.61 (Y/sub Zn/ = 0.61 X/sub Cd/ + 24.4), which corresponds to a nearly equimolar increase of zinc. The concentrations of ''physiological zinc,'' i.e., total zinc minus the zinc related to cadmium, were normally distributed (anti x = 24.6 ..mu..g Zn/g) and did not change with age. Furthermore, data on dry weight/wet weight ratios and ash weight/dry weight ratios in relation to age are presented.

  13. Medial prefrontal cortex role in recognition memory in rodents.

    Science.gov (United States)

    Morici, Juan Facundo; Bekinschtein, Pedro; Weisstaub, Noelia V

    2015-10-01

    The study of the neurobiology of recognition memory, defined by the integration of the different components of experiences that support recollection of past experiences have been a challenge for memory researches for many years. In the last twenty years, with the development of the spontaneous novel object recognition task and all its variants this has started to change. The features of recognition memory include a particular object or person ("what"), the context in which the experience took place, which can be the arena itself or the location within a particular arena ("where") and the particular time at which the event occurred ("when"). This definition instead of the historical anthropocentric one allows the study of this type of episodic memory in animal models. Some forms of recognition memory that require integration of different features recruit the medial prefrontal cortex. Focusing on findings from spontaneous recognition memory tasks performed by rodents, this review concentrates on the description of previous works that have examined the role that the medial prefrontal cortex has on the different steps of recognition memory. We conclude that this structure, independently of the task used, is required at different memory stages when the task cannot be solved by a single item strategy. PMID:26115848

  14. A multi-modal parcellation of human cerebral cortex.

    Science.gov (United States)

    Glasser, Matthew F; Coalson, Timothy S; Robinson, Emma C; Hacker, Carl D; Harwell, John; Yacoub, Essa; Ugurbil, Kamil; Andersson, Jesper; Beckmann, Christian F; Jenkinson, Mark; Smith, Stephen M; Van Essen, David C

    2016-08-11

    Understanding the amazingly complex human cerebral cortex requires a map (or parcellation) of its major subdivisions, known as cortical areas. Making an accurate areal map has been a century-old objective in neuroscience. Using multi-modal magnetic resonance images from the Human Connectome Project (HCP) and an objective semi-automated neuroanatomical approach, we delineated 180 areas per hemisphere bounded by sharp changes in cortical architecture, function, connectivity, and/or topography in a precisely aligned group average of 210 healthy young adults. We characterized 97 new areas and 83 areas previously reported using post-mortem microscopy or other specialized study-specific approaches. To enable automated delineation and identification of these areas in new HCP subjects and in future studies, we trained a machine-learning classifier to recognize the multi-modal 'fingerprint' of each cortical area. This classifier detected the presence of 96.6% of the cortical areas in new subjects, replicated the group parcellation, and could correctly locate areas in individuals with atypical parcellations. The freely available parcellation and classifier will enable substantially improved neuroanatomical precision for studies of the structural and functional organization of human cerebral cortex and its variation across individuals and in development, aging, and disease. PMID:27437579

  15. Sharing social touch in the primary somatosensory cortex.

    Science.gov (United States)

    Bolognini, Nadia; Rossetti, Angela; Fusaro, Martina; Vallar, Giuseppe; Miniussi, Carlo

    2014-07-01

    Touch has an emotional and communicative meaning, and it plays a crucial role in social perception and empathy. The intuitive link between others' somatosensations and our sense of touch becomes ostensible in mirror-touch synesthesia, a condition in which the view of a touch on another person's body elicits conscious tactile sensations on the observer's own body [1]. This peculiar phenomenon may implicate normal social mirror mechanisms [2]. Here, we show that mirror-touch interference effects, synesthesia-like sensations, and even phantom touches can be induced in nonsynesthetes by priming the primary somatosensory cortex (SI) directly or indirectly via the posterior parietal cortex. These results were obtained by means of facilitatory paired-pulse transcranial magnetic stimulation (ppTMS) contingent upon the observation of touch. For these vicarious effects, the SI is engaged at 150 ms from the onset of the visual touch. Intriguingly, individual differences in empathic abilities, assessed with the Interpersonal Reactivity Index [3], drive the activity of the SI when nonsynesthetes witness others' tactile sensations. This evidence implies that, under normal conditions, touch observation activates the SI below the threshold for perceptual awareness [4]; through the visual-dependent tuning of SI activity by ppTMS, what is seen becomes felt, namely, mirror-touch synesthesia. On a broader perspective, the visual responsivity of the SI may allow an automatic and unconscious transference of the sensation that another person is experiencing onto oneself, and, in turn, the empathic sharing of somatosensations [2]. PMID:24954046

  16. Semantics of the Visual Environment Encoded in Parahippocampal Cortex.

    Science.gov (United States)

    Bonner, Michael F; Price, Amy Rose; Peelle, Jonathan E; Grossman, Murray

    2016-03-01

    Semantic representations capture the statistics of experience and store this information in memory. A fundamental component of this memory system is knowledge of the visual environment, including knowledge of objects and their associations. Visual semantic information underlies a range of behaviors, from perceptual categorization to cognitive processes such as language and reasoning. Here we examine the neuroanatomic system that encodes visual semantics. Across three experiments, we found converging evidence indicating that knowledge of verbally mediated visual concepts relies on information encoded in a region of the ventral-medial temporal lobe centered on parahippocampal cortex. In an fMRI study, this region was strongly engaged by the processing of concepts relying on visual knowledge but not by concepts relying on other sensory modalities. In a study of patients with the semantic variant of primary progressive aphasia (semantic dementia), atrophy that encompassed this region was associated with a specific impairment in verbally mediated visual semantic knowledge. Finally, in a structural study of healthy adults from the fMRI experiment, gray matter density in this region related to individual variability in the processing of visual concepts. The anatomic location of these findings aligns with recent work linking the ventral-medial temporal lobe with high-level visual representation, contextual associations, and reasoning through imagination. Together, this work suggests a critical role for parahippocampal cortex in linking the visual environment with knowledge systems in the human brain. PMID:26679216

  17. The Representation of Prediction Error in Auditory Cortex

    Science.gov (United States)

    Rubin, Jonathan; Ulanovsky, Nachum; Tishby, Naftali

    2016-01-01

    To survive, organisms must extract information from the past that is relevant for their future. How this process is expressed at the neural level remains unclear. We address this problem by developing a novel approach from first principles. We show here how to generate low-complexity representations of the past that produce optimal predictions of future events. We then illustrate this framework by studying the coding of ‘oddball’ sequences in auditory cortex. We find that for many neurons in primary auditory cortex, trial-by-trial fluctuations of neuronal responses correlate with the theoretical prediction error calculated from the short-term past of the stimulation sequence, under constraints on the complexity of the representation of this past sequence. In some neurons, the effect of prediction error accounted for more than 50% of response variability. Reliable predictions often depended on a representation of the sequence of the last ten or more stimuli, although the representation kept only few details of that sequence. PMID:27490251

  18. Early network activity propagates bidirectionally between hippocampus and cortex.

    Science.gov (United States)

    Barger, Zeke; Easton, Curtis R; Neuzil, Kevin E; Moody, William J

    2016-06-01

    Spontaneous activity in the developing brain helps refine neuronal connections before the arrival of sensory-driven neuronal activity. In mouse neocortex during the first postnatal week, waves of spontaneous activity originating from pacemaker regions in the septal nucleus and piriform cortex propagate through the neocortex. Using high-speed Ca(2+) imaging to resolve the spatiotemporal dynamics of wave propagation in parasagittal mouse brain slices, we show that the hippocampus can act as an additional source of neocortical waves. Some waves that originate in the hippocampus remain restricted to that structure, while others pause at the hippocampus-neocortex boundary and then propagate into the neocortex. Blocking GABAergic neurotransmission decreases the likelihood of wave propagation into neocortex, whereas blocking glutamatergic neurotransmission eliminates spontaneous and evoked hippocampal waves. A subset of hippocampal and cortical waves trigger Ca(2+) waves in astrocytic networks after a brief delay. Hippocampal waves accompanied by Ca(2+) elevation in astrocytes are more likely to propagate into the neocortex. Finally, we show that two structures in our preparation that initiate waves-the hippocampus and the piriform cortex-can be electrically stimulated to initiate propagating waves at lower thresholds than the neocortex, indicating that the intrinsic circuit properties of those regions are responsible for their pacemaker function. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 76: 661-672, 2016. PMID:26385616

  19. pH regulation of an egg cortex tyrosine kinase.

    Science.gov (United States)

    Jiang, W P; Veno, P A; Wood, R W; Peaucellier, G; Kinsey, W H

    1991-07-01

    Fertilization of the echinoderm egg is known to result in the phosphorylation, on tyrosine, of a high-molecular-weight cortical protein (HMWCP) localized in the egg cortex. Studies using various parthenogenic agents indicate that this phosphorylation event occurs in response to the alkaline shift in cytoplasmic pHi which normally occurs 1 to 2 min after fertilization. In the present study, the purified egg cell surface complex was used as in vitro system to determine whether a small alkaline shift in pH, such as occurs upon fertilization, could stimulate the activity of the egg cortex-associated tyrosine kinase toward endogenous protein substrates. The results demonstrated that the cell surface complex is highly enriched in a tyrosine kinase activity which accounts for the majority of the protein kinase activity in this preparation. The activity of this tyrosine kinase toward the HMWCP and other cortical proteins was highly dependent on pH over the range pH 6.8 to 7.3. This indicates that the fertilization-associated change in cytoplasmic pH would be sufficient to trigger increased tyrosine phosphorylation of the high-molecular-weight cortical protein in vivo. The regulation of tyrosine phosphorylation by small changes in pH represents a novel control mechanism in which a tyrosine protein kinase may act as a pH-sensitive transducer. PMID:2060713

  20. Balanced feedforward inhibition and dominant recurrent inhibition in olfactory cortex.

    Science.gov (United States)

    Large, Adam M; Vogler, Nathan W; Mielo, Samantha; Oswald, Anne-Marie M

    2016-02-23

    Throughout the brain, the recruitment of feedforward and recurrent inhibition shapes neural responses. However, disentangling the relative contributions of these often-overlapping cortical circuits is challenging. The piriform cortex provides an ideal system to address this issue because the interneurons responsible for feedforward and recurrent inhibition are anatomically segregated in layer (L) 1 and L2/3 respectively. Here we use a combination of optical and electrical activation of interneurons to profile the inhibitory input received by three classes of principal excitatory neuron in the anterior piriform cortex. In all classes, we find that L1 interneurons provide weaker inhibition than L2/3 interneurons. Nonetheless, feedforward inhibitory strength covaries with the amount of afferent excitation received by each class of principal neuron. In contrast, intracortical stimulation of L2/3 evokes strong inhibition that dominates recurrent excitation in all classes. Finally, we find that the relative contributions of feedforward and recurrent pathways differ between principal neuron classes. Specifically, L2 neurons receive more reliable afferent drive and less overall inhibition than L3 neurons. Alternatively, L3 neurons receive substantially more intracortical inhibition. These three features--balanced afferent drive, dominant recurrent inhibition, and differential recruitment by afferent vs. intracortical circuits, dependent on cell class--suggest mechanisms for olfactory processing that may extend to other sensory cortices. PMID:26858458

  1. Increased Visual Stimulation Systematically Decreases Activity in Lateral Intermediate Cortex.

    Science.gov (United States)

    Nasr, Shahin; Stemmann, Heiko; Vanduffel, Wim; Tootell, Roger B H

    2015-10-01

    Previous studies have attributed multiple diverse roles to the posterior superior temporal cortex (STC), both visually driven and cognitive, including part of the default mode network (DMN). Here, we demonstrate a unifying property across this multimodal region. Specifically, the lateral intermediate (LIM) portion of STC showed an unexpected feature: a progressively decreasing fMRI response to increases in visual stimulus size (or number). Such responses are reversed in sign, relative to well-known responses in classic occipital temporal visual cortex. In LIM, this "reversed" size function was present across multiple object categories and retinotopic eccentricities. Moreover, we found a significant interaction between the LIM size function and the distribution of subjects' attention. These findings suggest that LIM serves as a part of the DMN. Further analysis of functional connectivity, plus a meta-analysis of previous fMRI results, suggests that LIM is a heterogeneous area including different subdivisions. Surprisingly, analogous fMRI tests in macaque monkeys did not reveal a clear homolog of LIM. This interspecies discrepancy supports the idea that self-referential thinking and theory of mind are more prominent in humans, compared with monkeys. PMID:25480358

  2. Morphological and functional correlates of VIP neurons in cerebral cortex

    International Nuclear Information System (INIS)

    Vasoactive Intestinal Polypeptide (VIP) promotes the hydrolysis of 3H-glycogen newly synthesized from 3H-glucose by mouse cortical slices. This effect occurs rapidly, approximately 50% of the maximal effect being reached within one minute. The maximal effect is achieved after 5 minutes and maintained for at least 25 minutes. Furthermore the glycogenolytic effect of VIP is reversible, and pharmacologically specific. Thus several neuropeptides present in cerebral cortex such as cholecystokinin-8, somatostatin-28, somatostatin-14, met-enkephalin, leu-enkephalin, do not affect 3H-glycogen levels. VIP fragments 6-28, 16-28 and 21-28 are similarly inactive. Furthermore, among the peptides which share structural homologies with VIP, such as glucagon, secretin, PHI-27 and Gastric Inhibitory Peptide, only secretin and PHI-27 promote 3H-glycogen hydrolysis, with EC50 of 500 and 300 nM respectively, compared to an EC50 of 25 nM for VIP. Immunohistochemical observations indicate that each VIP-containing bipolar cell is identified with a unique radical cortical volume, which is generally between 15-60 micrograms in diameter and overlaps with the contiguous domains of neighbouring VIP-containing bipolar cells. Thus this set of biochemical and morphological observations support the notion that VIP neurons have the capacity to regulate the availability of energy substrates in cerebral cortex locally, within circumscribed, contiguous, radial domains

  3. Porcine brain natriuretic peptide receptor in bovine adrenal cortex

    International Nuclear Information System (INIS)

    The action of porcine brain natriuretic peptide (pBNP) on the steroidogenesis was investigated in cultured bovine adrenocortical cells. Porcine BNP induced a significant dose-dependent inhibition of both ACTH- and A II-stimulated aldosterone secretion. 10/sup /minus/8/M and 10/sup /minus/7/M pBNP also significantly inhibited ACTH-stimulated cortisol and dehydroepiandrosterone (DHEA) secretions. Binding studies of [125I]-pBNP to bovine adrenocortical membrane fractions showed that adrenal cortex had high-affinity and low-capacity pBNP binding sites, with a dissociation constant (Kd) of 1.70 x 10/sup /minus/10/M and a maximal binding capacity (Bmax) of 19.9 fmol/mg protein. Finally, the 135 Kd radioactive band was specially visualized in the affinity labeling of bovine adrenal cortex with disuccinimidyl suberate (DSS). These results suggest that pBNP may have receptor-mediated suppressive actions on bovine adrenal steroidogenesis, similar to that in atrial natriuretic peptide

  4. Porcine brain natriuretic peptide receptor in bovine adrenal cortex

    Energy Technology Data Exchange (ETDEWEB)

    Higuchi, K.; Hashiguchi, T.; Ohashi, M.; Takayanagi, R.; Haji, M.; Matsuo, H.; Nawata, H.

    1989-01-01

    The action of porcine brain natriuretic peptide (pBNP) on the steroidogenesis was investigated in cultured bovine adrenocortical cells. Porcine BNP induced a significant dose-dependent inhibition of both ACTH- and A II-stimulated aldosterone secretion. 10/sup /minus/8/M and 10/sup /minus/7/M pBNP also significantly inhibited ACTH-stimulated cortisol and dehydroepiandrosterone (DHEA) secretions. Binding studies of (/sup 125/I)-pBNP to bovine adrenocortical membrane fractions showed that adrenal cortex had high-affinity and low-capacity pBNP binding sites, with a dissociation constant (Kd) of 1.70 x 10/sup /minus/10/M and a maximal binding capacity (Bmax) of 19.9 fmol/mg protein. Finally, the 135 Kd radioactive band was specially visualized in the affinity labeling of bovine adrenal cortex with disuccinimidyl suberate (DSS). These results suggest that pBNP may have receptor-mediated suppressive actions on bovine adrenal steroidogenesis, similar to that in atrial natriuretic peptide (ANP).

  5. Spatial diversity of spontaneous activity in the cortex

    Directory of Open Access Journals (Sweden)

    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.

  6. Medial prefrontal cortex-dorsal anterior cingulate cortex connectivity during behavior selection without an objective correct answer.

    Science.gov (United States)

    Nakao, Takashi; Osumi, Takahiro; Ohira, Hideki; Kasuya, Yukinori; Shinoda, Jun; Yamada, Jitsuhiro; Northoff, Georg

    2010-10-01

    Life choices (e.g., occupational choice) often include situations with two or more possible correct answers, thereby putting us in a situation of conflict. Recent reports have described that the evaluation of conflict might be crucially mediated by neural activity in the dorsal anterior cingulate cortex (dACC), although the reduction of conflict might rather be associated with neural activity in the medial prefrontal cortex (MPFC). What remains unclear is whether these regions mutually interact, thereby raising the question of their functional connectivity during conflict situations. Using psychophysiological interaction (PPI) analyses of functional magnetic resonance imaging (fMRI) data, this study shows that the dACC co-varied significantly higher with the MPFC during an occupational choice task with two possible correct answers when compared to the control task: a word-length task with one possible correct answer. These results suggest that the MPFC has a functional relation with dACC, especially in conflict situations where there is no objective correct answer. Taken together, this lends support to the assumption that the MPFC might be crucial in biasing the decision, thereby reducing conflict. PMID:20655361

  7. 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

  8. Midcingulate cortex: Structure, connections, homologies, functions and diseases.

    Science.gov (United States)

    Vogt, Brent A

    2016-07-01

    Midcingulate cortex (MCC) has risen in prominence as human imaging identifies unique structural and functional activity therein and this is the first review of its structure, connections, functions and disease vulnerabilities. The MCC has two divisions (anterior, aMCC and posterior, pMCC) that represent functional units and the cytoarchitecture, connections and neurocytology of each is shown with immunohistochemistry and receptor binding. The MCC is not a division of anterior cingulate cortex (ACC) and the "dorsal ACC" designation is a misnomer as it incorrectly implies that MCC is a division of ACC. Interpretation of findings among species and developing models of human diseases requires detailed comparative studies which is shown here for five species with flat maps and immunohistochemistry (human, monkey, rabbit, rat, mouse). The largest neurons in human cingulate cortex are in layer Vb of area 24 d in pMCC which project to the spinal cord. This area is part of the caudal cingulate premotor area which is involved in multisensory orientation of the head and body in space and neuron responses are tuned for the force and direction of movement. In contrast, the rostral cingulate premotor area in aMCC is involved in action-reinforcement associations and selection based on the amount of reward or aversive properties of a potential movement. The aMCC is activated by nociceptive information from the midline, mediodorsal and intralaminar thalamic nuclei which evoke fear and mediates nocifensive behaviors. This subregion also has high dopaminergic afferents and high dopamine-1 receptor binding and is engaged in reward processes. Opposing pain/avoidance and reward/approach functions are selected by assessment of potential outcomes and error detection according to feedback-mediated, decision making. Parietal afferents differentially terminate in MCC and provide for multisensory control in an eye- and head-centric manner. Finally, MCC vulnerability in human disease confirms

  9. Induction of motor associative plasticity in the posterior parietal cortex-primary motor network

    DEFF Research Database (Denmark)

    Chao, Chi-Chao; Karabanov, Anke Ninija; Paine, Rainer;

    2015-01-01

    There is anatomical and functional connectivity between the primary motor cortex (M1) and posterior parietal cortex (PPC) that plays a role in sensorimotor integration. In this study, we applied corticocortical paired-associative stimuli to ipsilateral PPC and M1 (parietal ccPAS) in healthy right...

  10. Williams Syndrome Hypersociability: A Neuropsychological Study of the Amygdala and Prefrontal Cortex Hypotheses

    Science.gov (United States)

    Capitao, Liliana; Sampaio, Adriana; Fernandez, Montse; Sousa, Nuno; Pinheiro, Ana; Goncalves, Oscar F.

    2011-01-01

    Individuals with Williams syndrome display indiscriminate approach towards strangers. Neuroimaging studies conducted so far have linked this social profile to structural and/or functional abnormalities in WS amygdala and prefrontal cortex. In this study, the neuropsychological hypotheses of amygdala and prefrontal cortex involvement in WS…

  11. Functional connectivity within the visual cortex of the rat shows state changes.

    NARCIS (Netherlands)

    C. van der Togt; V.A.F. Lamme; H. Spekreijse

    1998-01-01

    The aim of this study was to investigate the dynamics of the horizontal functional connectivity within the visual cortex during spontaneous activity or during visual stimulation. Two arrays of 16 electrodes were inserted in the visual cortex of a rat. From these electrodes a depth profile was Obtain

  12. Modality-specific involvement of occipital cortex in the early blind

    NARCIS (Netherlands)

    Lubbe, van der R.H.J.; Mierlo, van C.M.; Postma, A.

    2008-01-01

    What happens in occipital cortex when neuronal activity is no longer evoked by regular visual stimulation? Studying brain activity induced by tactile and auditory stimuli in the blind may provide an answer. Several studies indicate that occipital cortex in the blind is recruited in simple tasks, lik

  13. A Semi-Persistent Adult Ocular Dominance Plasticity in Visual Cortex Is Stabilized by Activated CREB

    Science.gov (United States)

    Barco, Angel; Kandel, Eric R.; Gordon, Barbara; Lickey, Marvin E.; Suzuki, Seigo; Pham, Tony A.; Graham, Sarah J.

    2004-01-01

    The adult cerebral cortex can adapt to environmental change. Using monocular deprivation as a paradigm, we find that rapid experience-dependent plasticity exists even in the mature primary visual cortex. However, adult cortical plasticity differs from developmental plasticity in two important ways. First, the effect of adult, but not juvenile…

  14. Revisiting the Role of the Prefrontal Cortex in the Pathophysiology of Attention-Deficit/Hyperactivity Disorder

    Science.gov (United States)

    Halperin, Jeffrey M.; Schulz, Kurt P.

    2006-01-01

    Most neural models for the pathophysiology of attention-deficit/hyperactivity disorder (ADHD) have centered on the prefrontal cortex and its interconnections with the striatum and other subcortical structures. However, research only partially supports these models, and they do not correspond with the development of the prefrontal cortex and its…

  15. Predicting the location of human perirhinal cortex, Brodmann's area 35, from MRI

    DEFF Research Database (Denmark)

    Augustinack, Jean C.; Huber, Kristen E.; Stevens, Allison A.;

    2013-01-01

    The perirhinal cortex (Brodmann's area 35) is a multimodal area that is important for normal memory function. Specifically, perirhinal cortex is involved in the detection of novel objects and manifests neurofibrillary tangles in Alzheimer's disease very early in disease progression. We scanned ex...

  16. Cryopreserved ovarian cortex from patients with leukemia in complete remission contains no apparent viable malignant cells

    DEFF Research Database (Denmark)

    Greve, Tine; Clasen-Linde, Erik; Andersen, Morten T; Andersen, Mette K; Sørensen, Stine D; Rosendahl, Mikkel; Ralfkiær, Elisabeth; Yding Andersen, Claus

    2012-01-01

    Some women suffering from leukemia require bone marrow transplantation to be cured. Bone marrow transplantation is associated with a high risk of sterility and some patients are offered fertility preservation by cryopreservation of ovarian cortex. Transplantation of ovarian cortex to women cured of...

  17. Continuous theta-burst stimulation of the primary motor cortex in essential tremor

    DEFF Research Database (Denmark)

    Hellriegel, Helge; Schulz, Eva M; Siebner, Hartwig R; Deuschl, Günther; Raethjen, Jan H

    2012-01-01

    We investigated whether essential tremor (ET) can be altered by suppressing the corticospinal excitability in the primary motor cortex (M1) with transcranial magnetic stimulation.......We investigated whether essential tremor (ET) can be altered by suppressing the corticospinal excitability in the primary motor cortex (M1) with transcranial magnetic stimulation....

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

    Science.gov (United States)

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

    2015-01-01

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

  19. Separating the influence of the cortex and foam on the mechanical properties of porcupine quills.

    Science.gov (United States)

    Yang, Wen; McKittrick, Joanna

    2013-11-01

    Lightweight thin cylinders filled with a foam have applications as collapsible energy absorbers for crashworthy and flotation applications. The local buckling compressive strength and Young's modulus are dependent on material and geometrical properties. Porcupine quills have a thin cortex filled with closed-cell foam, and are entirely composed of α-keratin. The cortex carries the majority of the compressive load, but the foam is able to accommodate and release some of the deformation of the cortex during buckling. The presence of the foam increases the critical buckling strength, buckling strain and elastic strain energy absorption over that of the cortex. Good agreement is found between experimental results and modeled predictions. A strain distribution map of the foam close to the buckled cortex demonstrates that the deformation of the cells plays an important role in accommodating local buckling of the cortex. The robust connection between the foam and cortex results in superior crushing properties compared to synthetic sandwich structure where the foam normally separates from the shell. The foam/cortex construction of the quill can guide future biomimetic fabrications of light weight buckle-resistant columns. PMID:23872514

  20. Inactivation of the Infralimbic but Not the Prelimbic Cortex Impairs Consolidation and Retrieval of Fear Extinction

    Science.gov (United States)

    Laurent, Vincent; Westbrook, R. Frederick

    2009-01-01

    Rats were subjected to one or two cycles of context fear conditioning and extinction to study the roles of the prelimbic cortex (PL) and infralimbic cortex (IL) in learning and relearning to inhibit fear responses. Inactivation of the PL depressed fear responses across the first or second extinction but did not impair learning or relearning fear…

  1. High-intensity Erotic Visual Stimuli De-activate the Primary Visual Cortex in Women

    NARCIS (Netherlands)

    Huynh, Hieu K.; Beers, Caroline; Willemsen, Antoon; Lont, Erna; Laan, Ellen; Dierckx, Rudi; Jansen, Monique; Sand, Michael; Schultz, Willibrord Weijmar; Holstege, Gert

    2012-01-01

    Introduction. 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 pict

  2. Dissociation of Subtraction and Multiplication in the Right Parietal Cortex: Evidence from Intraoperative Cortical Electrostimulation

    Science.gov (United States)

    Yu, Xiaodan; Chen, Chuansheng; Pu, Song; Wu, Chenxing; Li, Yongnian; Jiang, Tao; Zhou, Xinlin

    2011-01-01

    Previous research has consistently shown that the left parietal cortex is critical for numerical processing, but the role of the right parietal lobe has been much less clear. This study used the intraoperative cortical electrical stimulation approach to investigate neural dissociation in the right parietal cortex for subtraction and…

  3. A radial glia-specific role of RhoA in double cortex formation

    DEFF Research Database (Denmark)

    Cappello, Silvia; Böhringer, Christian R J; Bergami, Matteo;

    2012-01-01

    The positioning of neurons in the cerebral cortex is of crucial importance for its function as highlighted by the severe consequences of migrational disorders in patients. Here we show that genetic deletion of the small GTPase RhoA in the developing cerebral cortex results in two migrational diso...

  4. Sexual attraction enhances glutamate transmission in mammalian anterior cingulate cortex

    Directory of Open Access Journals (Sweden)

    Wu Long-Jun

    2009-05-01

    Full Text Available Abstract Functional human brain imaging studies have indicated the essential role of cortical regions, such as the anterior cingulate cortex (ACC, in romantic love and sex. However, the neurobiological basis of how the ACC neurons are activated and engaged in sexual attraction remains unknown. Using transgenic mice in which the expression of green fluorescent protein (GFP is controlled by the promoter of the activity-dependent gene c-fos, we found that ACC pyramidal neurons are activated by sexual attraction. The presynaptic glutamate release to the activated neurons is increased and pharmacological inhibition of neuronal activities in the ACC reduced the interest of male mice to female mice. Our results present direct evidence of the critical role of the ACC in sexual attraction, and long-term increases in glutamate mediated excitatory transmission may contribute to sexual attraction between male and female mice.

  5. Watching cartoons activates the medial prefrontal cortex in children

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The medial prefrontal cortex (MPFC) of human adults is involved in attributing mental states to real human agents but not to virtual artificial characters. This study examined whether such differential MPFC activity can be observed in children who are more fascinated by cartoons than adults. We measured brain activity using functional magnetic resonance imaging (fMRI) while 10-year-old children watched movie and cartoon clips, simulating real and virtual visual worlds, respectively. We showed neuroimaging evidence that, in contrast to adults, the MPFC of children was activated when perceiving both human agents and artificial characters in coherent visual events. Our findings suggest that, around the age of 10 years, the MPFC activity in children is different from that in adults in that it can be spontaneously activated by non-human agents in a virtual visual world.

  6. MDMA (ecstasy) modulates locomotor and prefrontal cortex sensory evoked activity.

    Science.gov (United States)

    Atkins, Kristal; Burks, Tilithia; Swann, Alan C; Dafny, Nachum

    2009-12-11

    Ingestion of 3, 4-methylenedioxymethamphetamine (MDMA) leads to heightened response to sensory stimulation; thus, MDMA is referred to as "ecstasy" because it produces pleasurable enhancement of such sensation. There have been no electrophysiological studies that report the consequences of MDMA on sensory input. The present study was initiated to study the effects of acute and chronic MDMA on locomotor activity and sensory evoked field potential from freely behaving rats previously implanted with permanent electrodes in the prefrontal cortex (PFC). The main findings of this study are that: (1) acute MDMA augments locomotor behavior and attenuates the incoming sensory input, (2) chronic treatment of MDMA elicits behavioral sensitization, (3) chronic administration of MDMA results in attenuation of the baseline activity of the sensory evoked field potential, and (4) administration of rechallenge MDMA result in enhancement of the PFC sensory evoked field potential. PMID:19769950

  7. Organization of texture segregation processing in primate visual cortex.

    Science.gov (United States)

    Lamme, V A; van Dijk, B W; Spekereijse, H

    1993-01-01

    We investigated the intracortical organization of neuronal mass activity that is related to texture segregation on the basis of orientation contrast. Evoked potentials were recorded to a stimulus, signalling a contribution from texture segregation-sensitive mechanisms by means of specific response components. The specific components could only be recorded when textons had a spatial organization that leads to the percept of image segmentation. Equivalent dipole estimations of the specific response components suggested the presence of texture segregation-related activity in the primary visual cortex. These results were corroborated by current-source-density analysis of intracortical recordings in the awake monkey. A specific involvement of layers 2/3 and 5 of area 17 in the global process of image segmentation could be demonstrated. PMID:8217932

  8. Behavioral effects of congenital ventromedial prefrontal cortex malformation

    Directory of Open Access Journals (Sweden)

    Boes Aaron D

    2011-12-01

    Full Text Available Abstract Background A detailed behavioral profile associated with focal congenital malformation of the ventromedial prefrontal cortex (vmPFC has not been reported previously. Here we describe a 14 year-old boy, B.W., with neurological and psychiatric sequelae stemming from focal cortical malformation of the left vmPFC. Case Presentation B.W.'s behavior has been characterized through extensive review Patience of clinical and personal records along with behavioral and neuropsychological testing. A central feature of the behavioral profile is severe antisocial behavior. He is aggressive, manipulative, and callous; features consistent with psychopathy. Other problems include: egocentricity, impulsivity, hyperactivity, lack of empathy, lack of respect for authority, impaired moral judgment, an inability to plan ahead, and poor frustration tolerance. Conclusions The vmPFC has a profound contribution to the development of human prosocial behavior. B.W. demonstrates how a congenital lesion to this cortical region severely disrupts this process.

  9. Metabifurcation analysis of a mean field model of the cortex

    CERN Document Server

    Frascoli, Federico; Bojak, Ingo; Liley, David T J

    2010-01-01

    Mean field models (MFMs) of cortical tissue incorporate salient features of neural masses to model activity at the population level. One of the common aspects of MFM descriptions is the presence of a high dimensional parameter space capturing neurobiological attributes relevant to brain dynamics. We study the physiological parameter space of a MFM of electrocortical activity and discover robust correlations between physiological attributes of the model cortex and its dynamical features. These correlations are revealed by the study of bifurcation plots, which show that the model responses to changes in inhibition belong to two families. After investigating and characterizing these, we discuss their essential differences in terms of four important aspects: power responses with respect to the modeled action of anesthetics, reaction to exogenous stimuli, distribution of model parameters and oscillatory repertoires when inhibition is enhanced. Furthermore, while the complexity of sustained periodic orbits differs ...

  10. Anterior insular cortex regulation in autism spectrum disorders

    Directory of Open Access Journals (Sweden)

    Andrea Caria

    2015-03-01

    Full Text Available Autism spectrum disorders (ASDs comprise a heterogeneous set of neurodevelopmental disorders characterized by dramatic impairments of interpersonal behavior, communication, and empathy. Recent neuroimaging studies suggested that ASD are disorders characterized by widespread abnormalities involving distributed brain network, though clear evidence of differences in large-scale brain network interactions underlying the cognitive and behavioral symptoms of ASD are still lacking. Consistent findings of anterior insula cortex hypoactivation and dysconnectivity during tasks related to emotional and social processing indicates its dysfunctional role in ASD. In parallel, increasing evidence showed that successful control of anterior insula activity can be attained using real-time fMRI paradigms. More importantly, successful regulation of this region was associated with changes in behavior and brain connectivity in both healthy individuals and psychiatric patients. Building on these results we here propose and discuss the use of real-time fMRI neurofeedback in ASD aiming at improving emotional and social behavior.

  11. Anterior insular cortex regulation in autism spectrum disorders.

    Science.gov (United States)

    Caria, Andrea; de Falco, Simona

    2015-01-01

    Autism spectrum disorders (ASDs) comprise a heterogeneous set of neurodevelopmental disorders characterized by dramatic impairments of interpersonal behavior, communication, and empathy. Recent neuroimaging studies suggested that ASD are disorders characterized by widespread abnormalities involving distributed brain network, though clear evidence of differences in large-scale brain network interactions underlying the cognitive and behavioral symptoms of ASD are still lacking. Consistent findings of anterior insula cortex hypoactivation and dysconnectivity during tasks related to emotional and social processing indicates its dysfunctional role in ASD. In parallel, increasing evidence showed that successful control of anterior insula activity can be attained using real-time fMRI paradigms. More importantly, successful regulation of this region was associated with changes in behavior and brain connectivity in both healthy individuals and psychiatric patients. Building on these results we here propose and discuss the use of real-time fMRI neurofeedback in ASD aiming at improving emotional and social behavior. PMID:25798096

  12. Chandelier neurons within the rabbits' cerebral cortex. A Golgi study.

    Science.gov (United States)

    Müller-Paschinger, I B; Tömböl, T; Petsche, H

    1983-01-01

    This study has been carried out by light microscopy on 3 Golgi-Kopsch impregnated brains of young adult rabbits. It is shown that chandelier cells exist within the rabbits' cerebral cortex. In the rabbit, the chandelier cell is a medium ranged bipolar interneuron in layer II/III with a characteristic axon which forms a plexus with a diameter of about 350-500 micrometers in the horizontal and 200-350 micrometers in the vertical direction; the end of each ramulus forms the typical "candlestick", a little vertical string of 1-6 boutons on an axon fibre. These boutons form contacts with all parts of pyramidal cells in layer II and the upper part of layer III. Similarities and differences with respect to previous descriptions of these cells in other species are discussed. PMID:6837931

  13. Unilateral Ibotenic Acid Lesions of the Prefrontal Cortex Reduce

    Directory of Open Access Journals (Sweden)

    Kuriyama,Shigeki

    2006-12-01

    Full Text Available Rats with 6-hydroxydopamine (6-OHDA-induced lesions of the substantia nigra are used as a model of Parkinson’s disease (PD, and these “lesioned” rats exhibit a rotational behavior when further injected with apomorphine (APO. We examined whether lesions in the prefrontal cortex (PFC could modify the rotational behavior in PD model rats. Rats initially received unilateral lesions of the substantia nigra by 6-OHDA injection, and then their rotational behavior was measured. Two PFC lesions were achieved by intracerebral infusions of ibotenic acid, followed by measurement of APOinduced rotation. Rotation was reduced by approximately 30オ after PFC injury. The PFC may have functional infl uences on the basal ganglia and may be involved in the pathophysiology of the rotational behavior of PD model rats.

  14. Cholinergic receptor binding in the frontal cortex of suicide victims

    International Nuclear Information System (INIS)

    Because there is a high incidence of individuals diagnosed as having an affective disorder who subsequently commit suicide, the author thought it would be of interest to determine QNB binding in the brains of a large sample of suicide victims, and to compare the findings with a well-matched control group. Brain samples were obtained at autopsy from 22 suicide victims and 22 controls. Frontal cortex samples were diseected, frozen, and stored until assayed. Samples of tissue homogenate were incubated in duplicate with 10 concentrations of tritium-QNB. Specific binding was determined with and without atropine. The results confirmed previous studies in which no changes were noted in suicide versus control brains. While the findings neither disprove nor support the cholinergic hypothesis of depression, they do suggest that the neurochemical basis for the in vivo observations of increased responsivity of depressed individuals to muscarinic cholinergic agents might not involve changes in receptors estimated by QNB binding

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

    DEFF Research Database (Denmark)

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

    1997-01-01

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

  16. Heterogeneous neural coding of corrective movements in motor cortex

    Science.gov (United States)

    Dickey, Adam S.; Amit, Yali; Hatsopoulos, Nicholas G.

    2013-01-01

    During a reach, neural activity recorded from motor cortex is typically thought to linearly encode the observed movement. However, it has also been reported that during a double-step reaching paradigm, neural coding of the original movement is replaced by that of the corrective movement. Here, we use neural data recorded from multi-electrode arrays implanted in the motor and premotor cortices of rhesus macaques to directly compare these two hypotheses. We show that while a majority of neurons display linear encoding of movement during a double-step, a minority display a dramatic drop in firing rate that is predicted by the replacement hypothesis. Neural activity in the subpopulation showing replacement is more likely to lag the observed movement, and may therefore be involved in the monitoring of the sensory consequences of a motor command. PMID:23576955

  17. Cerebral cortex: a target and source of insulin?

    Science.gov (United States)

    Csajbók, Éva A; Tamás, Gábor

    2016-08-01

    Recent results suggest that insulin is synthesised by a subpopulation of neurons in the cerebral cortex and neural progenitor cells of the hippocampus. Supplementing the slow supply of insulin to the brain by pancreatic beta cells, the insulin locally released by neurons provides a rapid means of regulating local microcircuits, effectively modulating synaptic transmission and on-demand energy homeostasis of neural networks. Modulation of insulin production by brain neurons via glucagon-like peptide 1 (GLP-1) agonists might be useful in counteracting diabetes, obesity and neurodegenerative diseases. Replacement of lost pancreatic beta cells by autologous transplantation of insulin-producing neural progenitor cells could be a viable therapy for diabetes. PMID:27207082

  18. Face representation in the human primary somatosensory cortex.

    Science.gov (United States)

    Nguyen, Binh T; Tran, Tuan D; Hoshiyama, Minoru; Inui, Koji; Kakigi, Ryusuke

    2004-10-01

    To investigate the representation of facial skin areas in the primary somatosensory cortex (SI), we recorded magnetic fields evoked by air pressure-induced tactile stimulation applied to six points on the face, lower lip and thumb. The thumb area in the SI was located more medial and superior to the lip area, which was consistent with Penfield's homunculus. However, the representations of all skin-covered areas including forehead, cheek, nose and chin in the SI were located between the thumb and lower lip area. There was no significant difference in location among the six facial points. Our results imply that lips occupy a large area of the face representation in the SI, whereas only a small area located between the thumb and lip areas is devoted to skin-covered surfaces. This is the first study showing that the facial skin areas in the human SI are located between the thumb and lower lip areas and close together. PMID:15380330

  19. Experimental determination of bone cortex holding power of orthopedic screw

    Directory of Open Access Journals (Sweden)

    Bolliger Neto Raul

    1999-01-01

    Full Text Available Cylindrical specimens of bone measuring 15 mm in diameter were obtained from the lateral cortical layer of 10 pairs of femurs and tibias. A central hole 3.2 mm in diameter was drilled in each specimen. The hole was tapped, and a 4.5 mm cortical bone screw was inserted from the outer surface. The montage was submitted to push-out testing up to a complete strip of the bone threads. The cortical thickness and rupture load were measured, and the shear stress was calculated. The results were grouped according to the bone segment from which the specimen was obtained. The results showed that bone cortex screw holding power is dependent on the bone site. Additionally, the diaphyseal cortical bone tissue is both quantitatively and qualitatively more resistant to screw extraction than the metaphyseal tissue.

  20. Multiple Running Speed Signals in Medial Entorhinal Cortex.

    Science.gov (United States)

    Hinman, James R; Brandon, Mark P; Climer, Jason R; Chapman, G William; Hasselmo, Michael E

    2016-08-01

    Grid cells in medial entorhinal cortex (MEC) can be modeled using oscillatory interference or attractor dynamic mechanisms that perform path integration, a computation requiring information about running direction and speed. The two classes of computational models often use either an oscillatory frequency or a firing rate that increases as a function of running speed. Yet it is currently not known whether these are two manifestations of the same speed signal or dissociable signals with potentially different anatomical substrates. We examined coding of running speed in MEC and identified these two speed signals to be independent of each other within individual neurons. The medial septum (MS) is strongly linked to locomotor behavior, and removal of MS input resulted in strengthening of the firing rate speed signal, while decreasing the strength of the oscillatory speed signal. Thus, two speed signals are present in MEC that are differentially affected by disrupted MS input. PMID:27427460

  1. Cholinergic Mechanisms in the Cerebral Cortex: Beyond Synaptic Transmission.

    Science.gov (United States)

    Ovsepian, Saak V; O'Leary, Valerie B; Zaborszky, Laszlo

    2016-06-01

    Functional overviews of cholinergic mechanisms in the cerebral cortex have traditionally focused on the release of acetylcholine with modulator and transmitter effects. Recently, however, data have emerged that extend the role of acetylcholine and cholinergic innervations to a range of housekeeping and metabolic functions. These include regulation of amyloid precursor protein (APP) processing with production of amyloid β (Aβ) and other APP fragments and control of the phosphorylation of microtubule-associated protein (MAP) tau. Evidence has been also presented for receptor-ligand like interactions of cholinergic receptors with soluble Aβ peptide and MAP tau, with modulator and signaling effects. Moreover, high-affinity binding of Aβ to the neurotrophin receptor p75 (p75NTR) enriched in basalo-cortical cholinergic projections has been implicated in clearance of Aβ and nucleation of amyloid plaques. Here, we critically evaluate these unorthodox cholinergic mechanisms and discuss their role in neuronal physiology and the biology of Alzheimer's disease. PMID:26002948

  2. The Behavioral Relevance of Task Information in Human Prefrontal Cortex.

    Science.gov (United States)

    Cole, Michael W; Ito, Takuya; Braver, Todd S

    2016-06-01

    Human lateral prefrontal cortex (LPFC) is thought to play a critical role in enabling cognitive flexibility, particularly when performing novel tasks. However, it remains to be established whether LPFC representation of task-relevant information in such situations actually contributes to successful performance. We utilized pattern classification analyses of functional MRI activity to identify novelty-sensitive brain regions as participants rapidly switched between performance of 64 complex tasks, 60 of which were novel. In three of these novelty-sensitive regions-located within distinct areas of left anterior LPFC-trial-evoked activity patterns discriminated correct from error trials. Further, these regions also contained information regarding the task-relevant decision rule, but only for successfully performed trials. This suggests that left anterior LPFC may be particularly important for representing task information that contributes to the cognitive flexibility needed to perform successfully in novel task situations. PMID:25870233

  3. [Effects of primary processing on quality of cortex Magnolia officinalis].

    Science.gov (United States)

    Yu, Shengxian; Zhang, Chunxia; Chen, Chengyu; Yan, Renyi; Yang, Bin; Liao, Chaolin; You, Jinwen

    2010-07-01

    In this paper, the changes of volatile oil and non-volatile ingredients in Cortex Magnolia Officinalis before and after primary processing were determined by an HPLC and a GC-MS method. The method is based on quantitative determination of three index ingredients, beta-eudesmol, honokiol and magnolol, and on qualitative fingerprinting analysis using HPLC and GC. Big differences were observed between processed and unprocessed samples according to their chromatographic fingerprinting data calculated by statistic software. Compared with unprocessed samples, the contents of honokiol and magnolol in processed samples increased, whereas the contents of beta-eudesmol and magnoloside A in processed samples decreased. Magnoloside A was isolated from this plant for the first time. PMID:20939279

  4. Transient contribution of left posterior parietal cortex to cognitive restructuring.

    Science.gov (United States)

    Sutoh, Chihiro; Matsuzawa, Daisuke; Hirano, Yoshiyuki; Yamada, Makiko; Nagaoka, Sawako; Chakraborty, Sudesna; Ishii, Daisuke; Matsuda, Shingo; Tomizawa, Haruna; Ito, Hiroshi; Tsuji, Hiroshi; Obata, Takayuki; Shimizu, Eiji

    2015-01-01

    Cognitive restructuring is a fundamental method within cognitive behavioural therapy of changing dysfunctional beliefs into flexible beliefs and learning to react appropriately to the reality of an anxiety-causing situation. To clarify the neural mechanisms of cognitive restructuring, we designed a unique task that replicated psychotherapy during a brain scan. The brain activities of healthy male participants were analysed using functional magnetic resonance imaging. During the brain scan, participants underwent Socratic questioning aimed at cognitive restructuring regarding the necessity of handwashing after using the restroom. The behavioural result indicated that the Socratic questioning effectively decreased the participants' degree of belief (DOB) that they must wash their hands. Alterations in the DOB showed a positive correlation with activity in the left posterior parietal cortex (PPC) while the subject thought about and rated own belief. The involvement of the left PPC not only in planning and decision-making but also in conceptualization may play a pivotal role in cognitive restructuring. PMID:25775998

  5. Neurochemical metabolites in the medial prefrontal cortex in bipolar disorder A proton magnetic resonance spectroscopy study

    Institute of Scientific and Technical Information of China (English)

    Osman (O)zdel; Demet Kalayci; Gülfizar S(o)zeri-Varma; Yilmaz Kiro(g)lu; Selim Tümkaya; Tu(g)(c)e Toker-U(g)urlu

    2012-01-01

    The aim of this study was to investigate proton magnetic resonance spectroscopy metabolite values in the medial prefrontal cortex of individuals with euthymic bipolar disorder. The subjects consisted of 15 patients with euthymic bipolar disorder type I and 15 healthy controls. We performed proton magnetic resonance spectroscopy of the bilateral medial prefrontal cortex and measured levels of N-acetyl aspartate, choline and creatine. Levels of these three metabolites in the medial prefrontal cortex were found to be lower in patients with bipolar disorder compared with healthy controls. A positive correlation was found between illness duration and choline levels in the right medial prefrontal cortex. Our study suggests that during the euthymic period, there are abnormalities in cellular energy and membrane phospholipid metabolism in the medial prefrontal cortex, and that this may impair neuronal activity and integrity.

  6. Positive affect modulates activity in the visual cortex to images of high calorie foods.

    Science.gov (United States)

    Killgore, William D S; Yurgelun-Todd, Deborah A

    2007-05-01

    Activity within the visual cortex can be influenced by the emotional salience of a stimulus, but it is not clear whether such cortical activity is modulated by the affective status of the individual. This study used functional magnetic resonance imaging (fMRI) to examine the relationship between affect ratings on the Positive and Negative Affect Schedule and activity within the occipital cortex of 13 normal-weight women while viewing images of high calorie and low calorie foods. Regression analyses revealed that when participants viewed high calorie foods, Positive Affect correlated significantly with activity within the lingual gyrus and calcarine cortex, whereas Negative Affect was unrelated to visual cortex activity. In contrast, during presentations of low calorie foods, affect ratings, regardless of valence, were unrelated to occipital cortex activity. These findings suggest a mechanism whereby positive affective state may affect the early stages of sensory processing, possibly influencing subsequent perceptual experience of a stimulus. PMID:17464782

  7. Creativity related cortex activity in the remote associates task.

    Science.gov (United States)

    Razumnikova, Olga M

    2007-06-15

    The involvement of different oscillating neuronal systems during verbal creative thinking was investigated by multi-channel EEG measuring. The remote associates task (RAT) as a model of creative thinking in comparison to the resting condition and the simple associates task (SAT) was used. The EEG coherence along with spectral power density estimates were evaluated in each of the six frequency bands in 4-30 Hz range. We have found out RAT-related EEG changes mainly in the theta1, alpha1, alpha2 and beta2 bands. The RAT-induced cortical activation was differed from the SAT-induced EEG pattern by (i) widespread enhancement of power and coherence in the beta2, (ii) the theta1 power increase in the frontal cortex, and (iii) increased desynchronization of the alpha1,alpha2 mainly over posterior cortex together with the alpha1 coherence decrease in the prefrontal sites. Originality scores of the verbal associates positively correlated with an increase of coherence focused in the fronto-parietal regions of both hemispheres in the beta2 and in the left parieto-temporal loci in the alpha1. Additionally, more original responses positively correlated with amplitude of the alpha1 mostly in the left hemisphere. We propose that widespread cortical integration of multi-component internal processing has been simultaneously mediated during creative verbal thinking. The selectively distributed theta, alpha, and beta oscillations reflect intra- and inter-hemispheric communication networks with different functional relations to the RAT solving. The theta1 and alpha1 rhythms seem to specifically relate to top-down information processing such as deliberate sustained attention and working-memory-retention during defocused attention, respectively, whereas larger interregional synchrony in the beta2 band may mediate 'differential' attention to diffusely activating alternative meanings of words and remote associates from coarse semantic coding. PMID:17499642

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

    Directory of Open Access Journals (Sweden)

    Eric Bean Knudsen

    2012-09-01

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

  9. Laminar circuit organization and response modulation in mouse visual cortex

    Directory of Open Access Journals (Sweden)

    Victor Quintanar-Zilinskas

    2012-10-01

    Full Text Available The mouse has become an increasingly important animal model for visual system studies, but few studies have investigated local functional circuit organization of mouse visual cortex. Here we used our newly developed mapping technique combining laser scanning photostimulation (LSPS with fast voltage-sensitive dye (VSD imaging to examine the spatial organization and temporal dynamics of laminar circuit responses in living slice preparations of mouse primary visual cortex (V1. During experiments, LSPS using caged glutamate provided spatially restricted neuronal activation in a specific cortical layer, and evoked responses from the stimulated layer to its functionally connected regions were detected by VSD imaging. In this study, we first provided a detailed analysis of spatiotemporal activation patterns at specific V1 laminar locations and measured local circuit connectivity. Then we examined the role of cortical inhibition in the propagation of evoked cortical responses by comparing circuit activity patterns in control and in the presence of GABAa receptor antagonists. We found that GABAergic inhibition was critical in restricting layer-specific excitatory activity spread and maintaining topographical projections. In addition, we investigated how AMPA and NMDA receptors influenced cortical responses and found that blocking AMPA receptors abolished interlaminar functional projections, and the NMDA receptor activity was important in controlling visual cortical circuit excitability and modulating activity propagation. The NMDA receptor antagonist reduced neuronal population activity in time-dependent and laminar-specific manners. Finally, we used the quantitative information derived from the mapping experiments and presented computational modeling analysis of V1 circuit organization. Taken together, the present study has provided important new information about mouse V1 circuit organization and response modulation.

  10. Retinotopically defined primary visual cortex in Williams syndrome.

    Science.gov (United States)

    Olsen, Rosanna K; Kippenhan, J Shane; Japee, Shruti; Kohn, Philip; Mervis, Carolyn B; Saad, Ziad S; Morris, Colleen A; Meyer-Lindenberg, Andreas; Berman, Karen Faith

    2009-03-01

    Williams syndrome, caused by a hemizygous microdeletion on chromosome 7q11.23, is characterized by severe impairment in visuospatial construction. To examine potential contributions of early visual processing to this cognitive problem, we functionally mapped the size and neuroanatomical variability of primary visual cortex (V1) in high-functioning adults with Williams syndrome and age- and IQ-matched control participants from the general population by using fMRI-based retinotopic mapping and cortical surface models generated from high-resolution structural MRI. Visual stimulation, consisting of rotating hemicircles and expanding rings, was used to retinotopically define early visual processing areas. V1 boundaries based on computed phase and field sign maps were used to calculate the functional area of V1. Neuroanatomical variability was assessed by computing overlap maps of V1 location for each group on standardized cortical surfaces, and non-parametric permutation test methods were used for statistical inference. V1 did not differ in size between groups, although its anatomical boundaries were more variable in the group with Williams syndrome. V1 overlap maps showed that the average centres of gravity for the two groups were similarly located near the fundus of the calcarine fissure, approximately 25 mm away from the most posterior aspect of the occipital lobe. In summary, our functional definition of V1 size and location indicates that recruitment of primary visual cortex is grossly normal in Williams syndrome, consistent with the notion that neural abnormalities underlying visuospatial construction arise at later stages in the visual processing hierarchy. PMID:19255058

  11. Anisotropy of ongoing neural activity in the primate visual cortex

    Directory of Open Access Journals (Sweden)

    Maier A

    2014-09-01

    Full Text Available Alexander Maier,1 Michele A Cox,1 Kacie Dougherty,1 Brandon Moore,1 David A Leopold2 1Department of Psychology, College of Arts and Science, Vanderbilt University, Nashville, TN, USA; 2Section on Cognitive Neurophysiology and Imaging, National Institute of Mental Health, National Institute of Health, Bethesda, MD, USA Abstract: The mammalian neocortex features distinct anatomical variation in its tangential and radial extents. This review consolidates previously published findings from our group in order to compare and contrast the spatial profile of neural activity coherence across these distinct cortical dimensions. We focus on studies of ongoing local field potential (LFP data obtained simultaneously from multiple sites in the primary visual cortex in two types of experiments in which electrode contacts were spaced either along the cortical surface or at different laminar positions. These studies demonstrate that across both dimensions the coherence of ongoing LFP fluctuations diminishes as a function of interelectrode distance, although the nature and spatial scale of this falloff is very different. Along the cortical surface, the overall LFP coherence declines gradually and continuously away from a given position. In contrast, across the cortical layers, LFP coherence is discontinuous and compartmentalized as a function of depth. Specifically, regions of high LFP coherence fall into discrete superficial and deep laminar zones, with an abrupt discontinuity between the granular and infragranular layers. This spatial pattern of ongoing LFP coherence is similar when animals are at rest and when they are engaged in a behavioral task. These results point to the existence of partially segregated laminar zones of cortical processing that extend tangentially within the laminar compartments and are thus oriented orthogonal to the cortical columns. We interpret these electrophysiological observations in light of the known anatomical organization of

  12. Phase sensitivity of complex cells in primary visual cortex.

    Science.gov (United States)

    Hietanen, M A; Cloherty, S L; van Kleef, J P; Wang, C; Dreher, B; Ibbotson, M R

    2013-05-01

    Neurons in the primary visual cortex are often classified as either simple or complex based on the linearity (or otherwise) of their response to spatial luminance contrast. In practice, classification is typically based on Fourier analysis of a cell's response to an optimal drifting sine-wave grating. Simple cells are generally considered to be linear and produce responses modulated at the fundamental frequency of the stimulus grating. In contrast, complex cells exhibit significant nonlinearities that reduce the response at the fundamental frequency. Cells can therefore be easily and objectively classified based on the relative modulation of their responses - the ratio of the phase-sensitive response at the fundamental frequency of the stimulus (F₁) to the phase-invariant sustained response (F₀). Cells are classified as simple if F₁/F₀>1 and complex if F₁/F₀<1. This classification is broadly consistent with criteria based on the spatial organisation of cells' receptive fields and is accordingly presumed to reflect disparate functional roles of simple and complex cells in coding visual information. However, Fourier analysis of spiking responses is sensitive to the number of spikes available - F₁/F₀ increases as the number of spikes is reduced, even for phase-invariant complex cells. Moreover, many complex cells encountered in the laboratory exhibit some phase sensitivity, evident as modulation of their responses at the fundamental frequency. There currently exists no objective quantitative means of assessing the significance or otherwise of these modulations. Here we derive a statistical basis for objectively assessing whether the modulation of neuronal responses is reliable, thereby adding a level of statistical certainty to measures of phase sensitivity. We apply our statistical analysis to neuronal responses to moving sine-wave gratings recorded from 367 cells in cat primary visual cortex. We find that approximately 60% of complex cells exhibit

  13. Perirhinal Cortex Hyperexcitability in Pilocarpine-Treated Epileptic Rats

    Science.gov (United States)

    Benini, Ruba; Longo, Daniela; Biagini, Giuseppe; Avoli, Massimo

    2016-01-01

    The perirhinal cortex (PC), which is heavily connected with several epileptogenic regions of the limbic system such as the entorhinal cortex and amygdala, is involved in the generation and spread of seizures. However, the functional alterations occurring within an epileptic PC network are unknown. Here, we analyzed this issue by using in vitro electrophysiology and immunohistochemistry in brain tissue obtained from pilocarpine-treated epileptic rats and age-matched, nonepileptic controls (NECs). Neurons recorded intracellularly from the PC deep layers in the two experimental groups had similar intrinsic and firing properties and generated spontaneous depolarizing and hyperpolarizing postsynaptic potentials with comparable duration and amplitude. However, spontaneous and stimulus-induced epileptiform discharges were seen with field potential recordings in over one-fifth of pilocarpine-treated slices but never in NEC tissue. These network events were reduced in duration by antagonizing NMDA receptors and abolished by NMDA + non-NMDA glutamatergic receptor antagonists. Pharmacologically isolated isolated inhibitory postsynaptic potentials had reversal potentials for the early GABAA receptor-mediated component that were significantly more depolarized in pilocarpine-treated cells. Experiments with a potassium-chloride cotransporter 2 antibody identified, in pilocarpine-treated PC, a significant immunostaining decrease that could not be explained by neuronal loss. However, interneurons expressing parvalbumin and neuropeptide Y were found to be decreased throughout the PC, whereas cholecystokinin-positive cells were diminished in superficial layers. These findings demonstrate synaptic hyper-excitability that is contributed by attenuated inhibition in the PC of pilocarpine-treated epileptic rats and underscore the role of PC networks in temporal lobe epilepsy. PMID:20865722

  14. Specialized pathways from the primate amygdala to posterior orbitofrontal cortex.

    Science.gov (United States)

    Timbie, Clare; Barbas, Helen

    2014-06-11

    The primate amygdala sends dense projections to posterior orbitofrontal cortex (pOFC) in pathways that are critical for processing emotional content, but the synaptic mechanisms are not understood. We addressed this issue by investigating pathways in rhesus monkeys (Macaca mulatta) from the amygdala to pOFC at the level of the system and synapse. Terminations from the amygdala were denser and larger in pOFC compared with the anterior cingulate cortex, which is also strongly connected with the amygdala. Axons from the amygdala terminated most densely in the upper layers of pOFC through large terminals. Most of these terminals innervated spines of presumed excitatory neurons and many were frequently multisynaptic and perforated, suggesting high synaptic efficacy. These amygdalar synapses in pOFC exceeded in size and specialization even thalamocortical terminals from the prefrontal-related thalamic mediodorsal nucleus to the middle cortical layers, which are thought to be highly efficient drivers of cortical neurons. Pathway terminals in the upper layers impinge on the apical dendrites of neurons in other layers, suggesting that the robust amygdalar projections may also activate neurons in layer 5 that project back to the amygdala and beyond to autonomic structures. Among inhibitory neurons, the amygdalar pathway innervated preferentially the neurochemical classes of calbindin and calretinin neurons in the upper layers of pOFC, which are synaptically suited to suppress noise and enhance signals. These features provide a circuit mechanism for flexibly shifting focus and adjusting emotional drive in processes disrupted in psychiatric disorders, such as phobias and obsessive-compulsive disorder. PMID:24920616

  15. Biosorption of heavy metals in polluted water, using different waste fruit cortex

    Science.gov (United States)

    Kelly-Vargas, Kevin; Cerro-Lopez, Monica; Reyna-Tellez, Silvia; Bandala, Erick R.; Sanchez-Salas, Jose Luis

    The biosorption capacity of different cortex fruit wastes including banana (Musa paradisiaca), lemon (Citrus limonum) and orange (Citrus sinensis) peel were evaluated. In order to perform these experiments, grinded dried cortexes were used as package in 100 mm high, 10 mm i.d. columns. The grinded material was powdered in a mortar and passed through a screen in order to get two different particle sizes, 2 and 1 mm, for all powders. To estimate the biosorption capabilities of the tested materials, different heavy metals were passed through the columns and the elution filtrate reloaded different times to increase the retention of metals. The heavy metals used were prepared as synthetic samples at 10 mg/L of Pb(NO3)2, Cd(NO3)2, and Cu(NO3)2·6H2O using primary standards. In preliminary experiments using banana cortex, it was found that material with 1 mm of particle size showed higher retention capability (up to12%) than the material with 2 mm of particle size. Considering these results, 1 mm particle size material was used in further experiments with the other waste materials. It was found that for Pb and Cu removal, lemon and orange cortex showed better biosorption capability when compared with banana cortex (up to 15% less for Pb and 48% less for Cu). For Cd, banana cortex showed better biosorption capability 57% (67.2 mg/g of cortex) more than orange (28.8 mg/g of cortex), and 82% more than lemon (12 mg/g of cortex). Reload of the columns with the filtrate after passing through the column improved the removal capability of all the materials tested from 10% to 50% depending on the cortex and metal tested.

  16. Mimicking the mechanical properties of the cell cortex by the self-assembly of an actin cortex in vesicles

    Science.gov (United States)

    Luo, Tianzhi; Srivastava, Vasudha; Ren, Yixin; Robinson, Douglas N.

    2014-04-01

    The composite of the actin cytoskeleton and plasma membrane plays important roles in many biological events. Here, we employed the emulsion method to synthesize artificial cells with biomimetic actin cortex in vesicles and characterized their mechanical properties. We demonstrated that the emulsion method provides the flexibility to adjust the lipid composition and protein concentrations in artificial cells to achieve the desired size distribution, internal microstructure, and mechanical properties. Moreover, comparison of the cortical elasticity measured for reconstituted artificial cells to that of real cells, including those manipulated using genetic depletion and pharmacological inhibition, strongly supports that actin cytoskeletal proteins are dominant over lipid molecules in cortical mechanics. Our study indicates that the assembly of biological systems in artificial cells with purified cellular components provides a powerful way to answer biological questions.

  17. Interactions between Pain and the Motor Cortex: Insights from Research on Phantom Limb Pain and Complex Regional Pain Syndrome

    OpenAIRE

    Mercier, Catherine; Léonard, Guillaume

    2011-01-01

    Purpose: Pain is a significantly disabling problem that often interacts with other deficits during the rehabilitation process. The aim of this paper is to review evidence of interactions between pain and the motor cortex in order to attempt to answer the following questions: (1) Does acute pain interfere with motor-cortex activity? (2) Does chronic pain interfere with motor-cortex activity, and, conversely, does motor-cortex plasticity contribute to chronic pain? (3) Can the induction of moto...

  18. Parcellation of the cingulate cortex at rest and during tasks: a meta-analytic clustering and experimental study

    OpenAIRE

    Torta, Diana M.E.; Tommaso Costa; Fox, Peter T.

    2013-01-01

    Anatomical, morphological, and histological data have consistently shown that the cingulate cortex can be divided into four main regions. However, less is known about parcellations of the cingulate cortex when involved in active tasks. Here, we aimed at comparing how the pattern of clusterization of the cingulate cortex changes across different levels of task complexity. We parcellated the cingulate cortex using the results of a meta-analytic study and of three experimental studies. The exper...

  19. Morphological dissociation between visual pathways and cortex: MRI of visually-deprived patients with congenital peripheral blindness

    International Nuclear Information System (INIS)

    MRI was used to study possible morphological changes in the visual system in 12 patients suffering from congenital blindness of peripheral (ocular) origin. While their optical pathways showed degeneration, hypoplasia or atrophy in 7 out of 12 cases, the occipital cortex appeared normal in all cases. This dissociation between afferent pathways and the cortex is contrary to the assumption that visually deprived cortex may undergo degeneration. The finding is congruent with evidence that the occipital cortex is used for other, nonvisual functions. (orig.)

  20. Evidence for broad versus segregated projections from cholinergic and noradrenergic nuclei to functionally and anatomically discrete subregions of prefrontal cortex

    OpenAIRE

    Chandler, Daniel J.

    2012-01-01

    The prefrontal cortex (PFC) is implicated in a variety of cognitive and executive operations. However, this region is not a single functional unit; rather, it is composed of several functionally and anatomically distinct networks, including anterior cingulate cortex (ACC), medial prefrontal cortex (mPFC) and orbitofrontal cortex (OFC). These prefrontal subregions serve dissociable behavioral functions, and are unique in their afferent and efferent connections. Each of these subregions is inne...

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

    Directory of Open Access Journals (Sweden)

    Jacqueline C Lieblein-Boff

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

  2. Activation of cannabinoid system in anterior cingulate cortex and orbitofrontal cortex modulates cost-benefit decision making.

    Science.gov (United States)

    Khani, Abbas; Kermani, Mojtaba; Hesam, Soghra; Haghparast, Abbas; Argandoña, Enrike G; Rainer, Gregor

    2015-06-01

    Despite the evidence for altered decision making in cannabis abusers, the role of the cannabinoid system in decision-making circuits has not been studied. Here, we examined the effects of cannabinoid modulation during cost-benefit decision making in the anterior cingulate cortex (ACC) and orbitofrontal cortex (OFC), key brain areas involved in decision making. We trained different groups of rats in a delay-based and an effort-based form of cost-benefit T-maze decision-making task. During test days, the rats received local injections of either vehicle or ACEA, a cannabinoid type-1 receptor (CB1R) agonist in the ACC or OFC. We measured spontaneous locomotor activity following the same treatments and characterized CB1Rs localization on different neuronal populations within these regions using immunohistochemistry. We showed that CB1R activation in the ACC impaired decision making such that rats were less willing to invest physical effort to gain high reward. Similarly, CB1R activation in the OFC induced impulsive pattern of choice such that rats preferred small immediate rewards to large delayed rewards. Control tasks ensured that the effects were specific for differential cost-benefit tasks. Furthermore, we characterized widespread colocalizations of CB1Rs on GABAergic axonal ends but few colocalizations on glutamatergic, dopaminergic, and serotonergic neuronal ends. These results provide first direct evidence that the cannabinoid system plays a critical role in regulating cost-benefit decision making in the ACC and OFC and implicate cannabinoid modulation of synaptic ends of predominantly interneurons and to a lesser degree other neuronal populations in these two frontal regions. PMID:25529106

  3. Protein Synthesis Inhibition in the Peri-Infarct Cortex Slows Motor Recovery in Rats

    Science.gov (United States)

    Schubring-Giese, Maximilian; Leemburg, Susan; Luft, Andreas Rüdiger; Hosp, Jonas Aurel

    2016-01-01

    Neuroplasticity and reorganization of brain motor networks are thought to enable recovery of motor function after ischemic stroke. Especially in the cortex surrounding the ischemic scar (i.e., peri-infarct cortex), evidence for lasting reorganization has been found at the level of neurons and networks. This reorganization depends on expression of specific genes and subsequent protein synthesis. To test the functional relevance of the peri-infarct cortex for recovery we assessed the effect of protein synthesis inhibition within this region after experimental stroke. Long-Evans rats were trained to perform a skilled-reaching task (SRT) until they reached plateau performance. A photothrombotic stroke was induced in the forelimb representation of the primary motor cortex (M1) contralateral to the trained paw. The SRT was re-trained after stroke while the protein synthesis inhibitor anisomycin (ANI) or saline were injected into the peri-infarct cortex through implanted cannulas. ANI injections reduced protein synthesis within the peri-infarct cortex by 69% and significantly impaired recovery of reaching performance through re-training. Improvement of motor performance within a single training session remained intact, while improvement between training sessions was impaired. ANI injections did not affect infarct size. Thus, protein synthesis inhibition within the peri-infarct cortex impairs recovery of motor deficits after ischemic stroke by interfering with consolidation of motor memory between training sessions but not short-term improvements within one session. PMID:27314672

  4. Differential grey matter changes in sensorimotor cortex related to exceptional fine motor skills.

    Directory of Open Access Journals (Sweden)

    M Cornelia Stoeckel

    Full Text Available Functional changes in sensorimotor representation occur in response to use and lesion throughout life. Emerging evidence suggests that functional changes are paralleled by respective macroscopic structural changes. In the present study we used voxel-based morphometry to investigate sensorimotor cortex in subjects with congenitally malformed upper extremities. We expected increased or decreased grey matter to parallel the enlarged or reduced functional representations we reported previously. More specifically, we expected decreased grey matter values in lateral sensorimotor cortex related to compromised hand function and increased grey matter values in medial sensorimotor cortex due to compensatory foot use. We found a medial cluster of grey matter increase in subjects with frequent, hand-like compensatory foot use. This increase was predominantly seen for lateral premotor, supplementary motor, and motor areas and only marginally involved somatosensory cortex. Contrary to our expectation, subjects with a reduced number of fingers, who had shown shrinkage of the functional hand representation previously, did not show decreased grey matter values within lateral sensorimotor cortex. Our data suggest that functional plastic changes in sensorimotor cortex can be associated with increases in grey matter but may also occur in otherwise macroscopically normal appearing grey matter volumes. Furthermore, macroscopic structural changes in motor and premotor areas may be observed without respective changes in somatosensory cortex.

  5. Motor Cortex Stimulation for Pain Relief: Do Corollary Discharges Play a Role?

    Science.gov (United States)

    Brasil-Neto, Joaquim P.

    2016-01-01

    Both invasive and non-invasive motor cortex stimulation techniques have been successfully employed in the treatment of chronic pain, but the precise mechanism of action of such treatments is not fully understood. It has been hypothesized that a mismatch of normal interaction between motor intention and sensory feedback may result in central pain. Sensory feedback may come from peripheral nerves, vision and also from corollary discharges originating from the motor cortex itself. Therefore, a possible mechanism of action of motor cortex stimulation might be corollary discharge reinforcement, which could counterbalance sensory feedback deficiency. In other instances, primary deficiency in the production of corollary discharges by the motor cortex might be the culprit and stimulation of cortical motor areas might then be beneficial by enhancing production of such discharges. Here we review evidence for a possible role of motor cortex corollary discharges upon both the pathophysiology and the response to motor cortex stimulation of different types of chronic pain. We further suggest that the right dorsolateral prefrontal cortex (DLPC), thought to constantly monitor incongruity between corollary discharges, vision and proprioception, might be an interesting target for non-invasive neuromodulation in cases of chronic neuropathic pain.

  6. Temporal Cortex Morphology in Mesial Temporal Lobe Epilepsy Patients and Their Asymptomatic Siblings.

    Science.gov (United States)

    Alhusaini, Saud; Whelan, Christopher D; Doherty, Colin P; Delanty, Norman; Fitzsimons, Mary; Cavalleri, Gianpiero L

    2016-03-01

    Temporal cortex abnormalities are common in patients with mesial temporal lobe epilepsy due to hippocampal sclerosis (MTLE+HS) and believed to be relevant to the underlying mechanisms. In the present study, we set out to determine the familiarity of temporal cortex morphologic alterations in a cohort of MTLE+HS patients and their asymptomatic siblings. A surface-based morphometry (SBM) method was applied to process MRI data acquired from 140 individuals (50 patients with unilateral MTLE+HS, 50 asymptomatic siblings of patients, and 40 healthy controls). Using a region-of-interest approach, alterations in temporal cortex morphology were determined in patients and their asymptomatic siblings by comparing with the controls. Alterations in temporal cortex morphology were identified in MTLE+HS patients ipsilaterally within the anterio-medial regions, including the entorhinal cortex, parahippocampal gyrus, and temporal pole. Subtle but similar pattern of morphology changes with a medium effect size were also noted in the asymptomatic siblings. These localized alterations were related to volume loss that appeared driven by shared contractions in cerebral cortex surface area. These findings indicate that temporal cortex morphologic alterations are common to patients and their asymptomatic siblings and suggest that such localized traits are possibly heritable. PMID:25576532

  7. Surface-Based Analyses of Anatomical Properties of the Visual Cortex in Macular Degeneration.

    Directory of Open Access Journals (Sweden)

    Doety Prins

    Full Text Available Macular degeneration (MD can cause a central visual field defect. In a previous study, we found volumetric reductions along the entire visual pathways of MD patients, possibly indicating degeneration of inactive neuronal tissue. This may have important implications. In particular, new therapeutic strategies to restore retinal function rely on intact visual pathways and cortex to reestablish visual function. Here we reanalyze the data of our previous study using surface-based morphometry (SBM rather than voxel-based morphometry (VBM. This can help determine the robustness of the findings and will lead to a better understanding of the nature of neuroanatomical changes associated with MD.The metrics of interest were acquired by performing SBM analysis on T1-weighted MRI data acquired from 113 subjects: patients with juvenile MD (JMD; n = 34, patients with age-related MD (AMD; n = 24 and healthy age-matched controls (HC; n = 55.Relative to age-matched controls, JMD patients showed a thinner cortex, a smaller cortical surface area and a lower grey matter volume in V1 and V2, while AMD patients showed thinning of the cortex in V2. Neither patient group showed a significant difference in mean curvature of the visual cortex.The thinner cortex, smaller surface area and lower grey matter volume in the visual cortex of JMD patients are consistent with our previous results showing a volumetric reduction in their visual cortex. Finding comparable results using two rather different analysis techniques suggests the presence of marked cortical degeneration in the JMD patients. In the AMD patients, we found a thinner cortex in V2 but not in V1. In contrast to our previous VBM analysis, SBM revealed no volumetric reductions of the visual cortex. This suggests that the cortical changes in AMD patients are relatively subtle, as they apparently can be missed by one of the methods.

  8. Representation of Maximally Regular Textures in Human Visual Cortex.

    Science.gov (United States)

    Kohler, Peter J; Clarke, Alasdair; Yakovleva, Alexandra; Liu, Yanxi; Norcia, Anthony M

    2016-01-20

    Naturalistic textures with an intermediate degree of statistical regularity can capture key structural features of natural images (Freeman and Simoncelli, 2011). V2 and later visual areas are sensitive to these features, while primary visual cortex is not (Freeman et al., 2013). Here we expand on this work by investigating a class of textures that have maximal formal regularity, the 17 crystallographic wallpaper groups (Fedorov, 1891). We used texture stimuli from four of the groups that differ in the maximum order of rotation symmetry they contain, and measured neural responses in human participants using functional MRI and high-density EEG. We found that cortical area V3 has a parametric representation of the rotation symmetries in the textures that is not present in either V1 or V2, the first discovery of a stimulus property that differentiates processing in V3 from that of lower-level areas. Parametric responses were also seen in higher-order ventral stream areas V4, VO1, and lateral occipital complex (LOC), but not in dorsal stream areas. The parametric response pattern was replicated in the EEG data, and source localization indicated that responses in V3 and V4 lead responses in LOC, which is consistent with a feedforward mechanism. Finally, we presented our stimuli to four well developed feedforward models and found that none of them were able to account for our results. Our results highlight structural regularity as an important stimulus dimension for distinguishing the early stages of visual processing, and suggest a previously unrecognized role for V3 in the visual form-processing hierarchy. Significance statement: Hierarchical processing is a fundamental organizing principle in visual neuroscience, with each successive processing stage being sensitive to increasingly complex stimulus properties. Here, we probe the encoding hierarchy in human visual cortex using a class of visual textures--wallpaper patterns--that are maximally regular. Through a

  9. Double Cortex Syndrome (Subcortical Band Heterotopia: A Case Report

    Directory of Open Access Journals (Sweden)

    Ali Akbar MOMEN

    2015-06-01

    Full Text Available AbstractObjectiveApproximately 5–10% of preschool age children are considered developmentally disabled. Brain Magnetic Resonance Imaging (MRI plays a key role in the diagnostic evaluation in these children. Many congenital or acquired brain anomalies are revealed with MRIs. Although the majority of these abnormalities are sporadic but patients with subcortical band heterotopia or double cortex syndrome have sex-linked inheritance. We are going to present the first case in Iran from Ahvaz city, which was presented with status epilepticus associated with developmental delay and finally diagnosed as double cortex syndrome, because band heterotopia cases especially for continuous or generalized form is rare.A 4.5-year-old developmentally delayed girl was admitted for generalized tonic clonic seizure attack of 1 hr, upward gaze, locked mouth, and urinary incontinence (status epilepticus in the child neurology ward. She had a history of recurrent seizures that started as febrile seizures since she was 12 months of age and had frequent admissions for having recurrent seizure attacks. She was the only child of consanguineous parents with negative family history of any neurologic problems. She was a product of uneventful term pregnancy, vaginal delivery with a low Apgar score at birth who was admitted for six days in the neonatal ward for hypotonia and cyanosis. At 4.5 years of age, she had HC: 45cm (<3% Length: 102 cm (25–75%, and BW: 18kg (75%.She was able to sit, walk with support, speak a few words, and communicate with others. A physical exam was unremarkable. Lab data including CBC, blood biochemical, and urinalysis results were all within normal limits, but the electroencephalography (EEG revealed generalized poly spike-wave discharges. A brain MRI showed corpus callosal dysplasia, generalized band heterotopia, and polymicrogyria. She was discharged home with oral valproate and regular outpatient follow-ups.In the diagnostic evaluation of

  10. Model for Probing Membrane-Cortex Adhesion by Micropipette Aspiration and Fluctuation Spectroscopy

    Science.gov (United States)

    Alert, Ricard; Casademunt, Jaume; Brugués, Jan; Sens, Pierre

    2015-04-01

    We propose a model for membrane-cortex adhesion which couples membrane deformations, hydrodynamics and kinetics of membrane-cortex ligands. In its simplest form, the model gives explicit predictions for the critical pressure for membrane detachment and for the value of adhesion energy. We show that these quantities exhibit a significant dependence on the active acto-myosin stresses. The model provides a simple framework to access quantitative information on cortical activity by means of micropipette experiments. We also extend the model to incorporate fluctuations and show that detailed information on the stability of membrane-cortex coupling can be obtained by a combination of micropipette aspiration and fluctuation spectroscopy measurements.

  11. Translaminar Inhibitory Cells Recruited by Layer 6 Cortico-Thalamic Neurons Suppress Visual Cortex

    OpenAIRE

    Bortone, Dante S.; Olsen, Shawn R.; Scanziani, Massimo

    2014-01-01

    In layer 6 (L6), a principal output layer of the mammalian cerebral cortex, a population of excitatory neurons defined by the NTSR1-Cre mouse line inhibit cortical responses to visual stimuli. Here we show that of the two major types of excitatory neurons existing in L6, the NTSR1-Cre line selectively targets those whose axon innervate both cortex and thalamus and not those whose axons remain within the cortex. These cortico-thalamic neurons mediate widespread inhibition across all cortical l...

  12. Model for probing membrane-cortex adhesion by micropipette aspiration and fluctuation spectroscopy

    CERN Document Server

    Alert, Ricard; Brugués, Jan; Sens, Pierre

    2016-01-01

    We propose a model for membrane-cortex adhesion which couples membrane deformations, hydrodynamics and kinetics of membrane-cortex ligands. In its simplest form, the model gives explicit predictions for the critical pressure for membrane detachment and for the value of adhesion energy. We show that these quantities exhibit a significant dependence on the active acto-myosin stresses. The model provides a simple framework to access quantitative information on cortical activity by means of micropipette experiments. We also extend the model to incorporate fluctuations and show that detailed information on the stability of membrane-cortex coupling can be obtained by a combination of micropipette aspiration and fluctuation spectroscopy measurements.

  13. ROLE OF RGS14 PROTEIN IN VISUALMEMORYAND THE REGULATION OF SYNAPTIC PLASTICITY IN PERIRHINAL CORTEX

    OpenAIRE

    Masmudi-Martin, Mariam; Posadas, Sinforiano Jose; Navarro Lobato, Irene; Delgado, Gloria; Lopez-Tellez, Juan Felix; Bashir, Z.I.; Khan, ZU

    2013-01-01

    Though the concept of participation of perirhinal cortex and frontal cortex in the processing of object memory has long been appreciated, but recently our laboratory extended this to area V2 of visual cortex. We found that activation of area V2 neurons by overexpression of RGS14 protein led to an enhancement of object recognition memory. The memory enhancement was of such extent that it converted the short term memory of 45 minutes into long lasting long-term memory that could be traced even ...

  14. Auditory Association Cortex Lesions Impair Auditory Short-Term Memory in Monkeys

    Science.gov (United States)

    Colombo, Michael; D'Amato, Michael R.; Rodman, Hillary R.; Gross, Charles G.

    1990-01-01

    Monkeys that were trained to perform auditory and visual short-term memory tasks (delayed matching-to-sample) received lesions of the auditory association cortex in the superior temporal gyrus. Although visual memory was completely unaffected by the lesions, auditory memory was severely impaired. Despite this impairment, all monkeys could discriminate sounds closer in frequency than those used in the auditory memory task. This result suggests that the superior temporal cortex plays a role in auditory processing and retention similar to the role the inferior temporal cortex plays in visual processing and retention.

  15. Functional Magnetic Resonance Imaging of Motor Cortex: Hemispheric Asymmetry and Handedness

    Science.gov (United States)

    Kim, Seong-Gi; Ashe, James; Hendrich, Kristy; Ellermann, Jutta M.; Merkle, Hellmut; Ugurbil, Kamil; Georgopoulos, Apostolos P.

    1993-07-01

    A hemispheric asymmetry in the functional activation of the human motor cortex during contralateral (C) and ipsilateral (I) finger movements, especially in right-handed subjects, was documented with nuclear magnetic resonance imaging at high field strength (4 tesla). Whereas the right motor cortex was activated mostly during contralateral finger movements in both right-handed (C/I mean area of activation = 36.8) and left-handed (C/I = 29.9) subjects, the left motor cortex was activated substantially during ipsilateral movements in left-handed subjects (C/I = 5.4) and even more so in right-handed subjects (C/I = 1.3).

  16. Motor cortex electric stimulation for the treatment of neuropathic pain

    Directory of Open Access Journals (Sweden)

    Walter J. Fagundes-Pereyra

    2010-12-01

    Full Text Available OBJECTIVE: Motor cortex stimulation (MCS is considered to be an effective treatment for chronic neuropathic pain. The aim of the present study was to assess the efficacy of MCS for treating neuropathic pain. METHOD: 27 patients with chronic neuropathic pain were operated. Electrodes were implanted with the use of an stereotactic frame. Electrophysiological evaluations (motor stimulation and somatosensory evoked potentials were performed, with guidance by means of three-dimensional reconstruction of magnetic resonance images of the brain. 10 patients (37% presented central neuropathic pain (post-stroke pain and 17 others (63% presented peripheral neuropathic pain (brachial plexus avulsion, phantom limb pain or trigeminal pain. RESULTS: In 15 patients (57.7% the pain relief was 50% or more; while in ten patients (38.5%, more than 60% of the original pain was relieved. No differences were found in relation to central and peripheral neuropathic pain (p=0.90, pain location (p=0.81, presence of motor deficit (p=0.28 and pain duration (p=0.72. No major complications were observed. CONCLUSION: MCS was efficient for treating patients presenting chronic central or peripheral neuropathic pain.

  17. Stereoscopic vision in the absence of the lateral occipital cortex.

    Directory of Open Access Journals (Sweden)

    Jenny C A Read

    Full Text Available Both dorsal and ventral cortical visual streams contain neurons sensitive to binocular disparities, but the two streams may underlie different aspects of stereoscopic vision. Here we investigate stereopsis in the neurological patient D.F., whose ventral stream, specifically lateral occipital cortex, has been damaged bilaterally, causing profound visual form agnosia. Despite her severe damage to cortical visual areas, we report that DF's stereo vision is strikingly unimpaired. She is better than many control observers at using binocular disparity to judge whether an isolated object appears near or far, and to resolve ambiguous structure-from-motion. DF is, however, poor at using relative disparity between features at different locations across the visual field. This may stem from a difficulty in identifying the surface boundaries where relative disparity is available. We suggest that the ventral processing stream may play a critical role in enabling healthy observers to extract fine depth information from relative disparities within one surface or between surfaces located in different parts of the visual field.

  18. Dreamed movement elicits activation in the sensorimotor cortex.

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    Dresler, Martin; Koch, Stefan P; Wehrle, Renate; Spoormaker, Victor I; Holsboer, Florian; Steiger, Axel; Sämann, Philipp G; Obrig, Hellmuth; Czisch, Michael

    2011-11-01

    Since the discovery of the close association between rapid eye movement (REM) sleep and dreaming, much effort has been devoted to link physiological signatures of REM sleep to the contents of associated dreams [1-4]. Due to the impossibility of experimentally controlling spontaneous dream activity, however, a direct demonstration of dream contents by neuroimaging methods is lacking. By combining brain imaging with polysomnography and exploiting the state of "lucid dreaming," we show here that a predefined motor task performed during dreaming elicits neuronal activation in the sensorimotor cortex. In lucid dreams, the subject is aware of the dreaming state and capable of performing predefined actions while all standard polysomnographic criteria of REM sleep are fulfilled [5, 6]. Using eye signals as temporal markers, neural activity measured by functional magnetic resonance imaging (fMRI) and near-infrared spectroscopy (NIRS) was related to dreamed hand movements during lucid REM sleep. Though preliminary, we provide first evidence that specific contents of REM-associated dreaming can be visualized by neuroimaging. PMID:22036177

  19. Enhanced representation of spectral contrasts in the primary auditory cortex

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    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.

  20. Susceptibility to social pressure following ventromedial prefrontal cortex damage.

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    Chen, Kuan-Hua; Rusch, Michelle L; Dawson, Jeffrey D; Rizzo, Matthew; Anderson, Steven W

    2015-11-01

    Social pressure influences human behavior including risk taking, but the psychological and neural underpinnings of this process are not well understood. We used the human lesion method to probe the role of ventromedial prefrontal cortex (vmPFC) in resisting adverse social pressure in the presence of risk. Thirty-seven participants (11 with vmPFC damage, 12 with brain damage outside the vmPFC and 14 without brain damage) were tested in driving simulator scenarios requiring left-turn decisions across oncoming traffic with varying time gaps between the oncoming vehicles. Social pressure was applied by a virtual driver who honked aggressively from behind. Participants with vmPFC damage were more likely to select smaller and potentially unsafe gaps under social pressure, while gap selection by the comparison groups did not change under social pressure. Participants with vmPFC damage also showed prolonged elevated skin conductance responses (SCR) under social pressure. Comparison groups showed similar initial elevated SCR, which then declined prior to making left-turn decisions. The findings suggest that the vmPFC plays an important role in resisting explicit and immediately present social pressure with potentially negative consequences. The vmPFC appears to contribute to the regulation of emotional responses and the modulation of decision making to optimize long-term outcomes. PMID:25816815

  1. Cingulate cortex hypoperfusion predicts Alzheimer's disease in mild cognitive impairment

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    Svensson Leif

    2002-09-01

    Full Text Available Abstract Background Mild cognitive impairment (MCI was recently described as a heterogeneous group with a variety of clinical outcomes and high risk to develop Alzheimer's disease (AD. Regional cerebral blood flow (rCBF as measured by single photon emission computed tomography (SPECT was used to study the heterogeneity of MCI and to look for predictors of future development of AD. Methods rCBF was investigated in 54 MCI subjects using Tc-99m hexamethylpropyleneamine oxime (HMPAO. An automated analysis software (BRASS was applied to analyze the relative blood flow (cerebellar ratios of 24 cortical regions. After the baseline examination, the subjects were followed clinically for an average of two years. 17 subjects progressed to Alzheimer's disease (PMCI and 37 subjects remained stable (SMCI. The baseline SPECT ratio values were compared between PMCI and SMCI. Receiver operating characteristic (ROC analysis was applied for the discrimination of the two subgroups at baseline. Results The conversion rate of MCI to AD was 13.7% per year. PMCI had a significantly decreased rCBF in the left posterior cingulate cortex, as compared to SMCI. Left posterior cingulate rCBF ratios were entered into a logistic regression model for ROC curve calculation. The area under the ROC curve was 74%–76%, which indicates an acceptable discrimination between PMCI and SMCI at baseline. Conclusion A reduced relative blood flow of the posterior cingulate gyrus could be found at least two years before the patients met the clinical diagnostic criteria of AD.

  2. How Invariant Feature Selectivity Is Achieved in Cortex.

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    Sharpee, Tatyana O

    2016-01-01

    Parsing the visual scene into objects is paramount to survival. Yet, how this is accomplished by the nervous system remains largely unknown, even in the comparatively well understood visual system. It is especially unclear how detailed peripheral signal representations are transformed into the object-oriented representations that are independent of object position and are provided by the final stages of visual processing. This perspective discusses advances in computational algorithms for fitting large-scale models that make it possible to reconstruct the intermediate steps of visual processing based on neural responses to natural stimuli. In particular, it is now possible to characterize how different types of position invariance, such as local (also known as phase invariance) and more global, are interleaved with nonlinear operations to allow for coding of curved contours. Neurons in the mid-level visual area V4 exhibit selectivity to pairs of even- and odd-symmetric profiles along curved contours. Such pairing is reminiscent of the response properties of complex cells in the primary visual cortex (V1) and suggests specific ways in which V1 signals are transformed within subsequent visual cortical areas. These examples illustrate that large-scale models fitted to neural responses to natural stimuli can provide generative models of successive stages of sensory processing. PMID:27601991

  3. Multidimensional representation of odors in the human olfactory cortex.

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    Fournel, A; Ferdenzi, C; Sezille, C; Rouby, C; Bensafi, M

    2016-06-01

    What is known as an odor object is an integrated representation constructed from physical features, and perceptual attributes mainly mediated by the olfactory and trigeminal systems. The aim of the present study was to comprehend how this multidimensional representation is organized, by deciphering how similarities in the physical, olfactory and trigeminal perceptual spaces of odors are represented in the human brain. To achieve this aim, we combined psychophysics, functional MRI and multivariate representational similarity analysis. Participants were asked to smell odors diffused by an fMRI-compatible olfactometer and to rate each smell along olfactory dimensions (pleasantness, intensity, familiarity and edibility) and trigeminal dimensions (irritation, coolness, warmth and pain). An event-related design was implemented, presenting different odorants. Results revealed that (i) pairwise odorant similarities in anterior piriform cortex (PC) activity correlated with pairwise odorant similarities in chemical properties (P trigeminal perceptual properties (P trigeminal features is based on specific fine processing of similarities between odorous stimuli in a distributed manner in the olfactory system. Hum Brain Mapp 37:2161-2172, 2016. © 2016 Wiley Periodicals, Inc. PMID:26991044

  4. Acoustic trauma-induced auditory cortex enhancement and tinnitus

    Institute of Scientific and Technical Information of China (English)

    Erin Laundrie; Wei Sun

    2014-01-01

    There is growing evidence suggests that noise-induced cochlear damage may lead to hyperexcitability in the central auditory system (CAS) which may give rise to tinnitus. However, the correlation between the onset of the neurophysiological changes in the CAS and the onset of tinnitus has not been well studied. To investigate this relationship, chronic electrodes were implanted into the auditory cortex (AC) and sound evoked activities were measured from awake rats before and after noise exposure. The auditory brainstem response (ABR) was used to assess the degree of noise-induced hearing loss. Tinnitus was evaluated by measuring gap-induced prepulse inhibition (gap-PPI). Rats were exposed monaurally to a high-intensity narrowband noise centered at 12 kHz at a level of 120 dB SPL for 1 h. After the noise exposure, all the rats developed either permanent (>2 weeks) or temporary (<3 days) hearing loss in the exposed ear(s). The AC amplitudes increased significantly 4 h after the noise exposure. Most of the exposed rats also showed decreased gap-PPI. The post-exposure AC enhancement showed a positive correlation with the amount of hearing loss. The onset of tinnitus-like behavior was happened after the onset of AC enhancement.

  5. Learning Warps Object Representations in the Ventral Temporal Cortex.

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    Clarke, Alex; Pell, Philip J; Ranganath, Charan; Tyler, Lorraine K

    2016-07-01

    The human ventral temporal cortex (VTC) plays a critical role in object recognition. Although it is well established that visual experience shapes VTC object representations, the impact of semantic and contextual learning is unclear. In this study, we tracked changes in representations of novel visual objects that emerged after learning meaningful information about each object. Over multiple training sessions, participants learned to associate semantic features (e.g., "made of wood," "floats") and spatial contextual associations (e.g., "found in gardens") with novel objects. fMRI was used to examine VTC activity for objects before and after learning. Multivariate pattern similarity analyses revealed that, after learning, VTC activity patterns carried information about the learned contextual associations of the objects, such that objects with contextual associations exhibited higher pattern similarity after learning. Furthermore, these learning-induced increases in pattern information about contextual associations were correlated with reductions in pattern information about the object's visual features. In a second experiment, we validated that these contextual effects translated to real-life objects. Our findings demonstrate that visual object representations in VTC are shaped by the knowledge we have about objects and show that object representations can flexibly adapt as a consequence of learning with the changes related to the specific kind of newly acquired information. PMID:26967942

  6. Microtubules in the Cerebral Cortex: Role in Memory and Consciousness

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    Woolf, Nancy J.

    This chapter raises the question whether synaptic connections in the cerebral cortex are adequate in accounting for higher cognition, especially cognition involving multimodal processing. A recent and novel approach to brain mechanics is outlined, one that involves microtubules and microtubule-associated protein-2 (MAP2). In addition to effects on the neuronal membrane, neurotransmitters exert actions on microtubules. These neurotransmitter effects alter the MAP2 phosphorylation state and rates of microtubule polymerization and transport. It is argued that these processes are important to the physical basis of memory and consciousness. In support of this argument, MAP2 is degraded with learning in discrete cortical modules. How this relates to synaptic change related to learning is unknown. The specific proposal is advanced that learning alters microtubules in the subsynaptic zone lying beneath the synapse, and that this forms the physical basis of long-term memory storage because microtubule networks determine the synapse strength by directing contacts with actin filaments and transport of synaptic proteins. It is argued that this is more probable than memory-related physical storage in the synapse itself. Comparisons to consciousness are made and it is concluded that there is a link between microtubules, memory and consciousness.

  7. Receptive field plasticity of neurons in rat auditory cortex

    Institute of Scientific and Technical Information of China (English)

    YANG Wenwei; GAO Lixia; SUN Xinde

    2004-01-01

    Using conventional electrophysiological technique, we investigated the plasticity of the frequency receptive fields (RF) of auditory cortex (AC) neurons in rats. In the AC, when the frequency difference between conditioning stimulus frequency (CSF) and the best frequency (BF) was in the range of 1-4 kHz, the frequency RF of AC neurons shifted. The smaller the differences between CSF and BF, the higher the probability of the RF shift and the greater the degree of the RF shift. To some extent, the plasticity of RF was dependent on the duration of the session of conditioning stimulus (CS). When the frequency difference between CSF and BF was bigger, the duration of the CS session needed to induce the plasticity was longer. The recovery time course of the frequency RF showed opposite changes after CS cessation.The RF shift could be induced by the frequency that was either higher or lower than the control BF, demonstrating no clear directional preference. The frequency RF of some neurons showed bidirectional shift, and the RF of other neurons showed single directional shift. The results suggest that the frequency RF plasticity of AC neurons could be considered as an ideal model for studying plasticity mechanism. The present study also provides important evidence for further study of learning and memory in auditory system.

  8. Reorganization of neuronal circuits in growing visual cortex

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    Keil, Wolfgang; Loewel, Siegrid; Wolf, Fred; Kaschube, Matthias

    2009-03-01

    The dynamics of reorganization of large cortical circuits is rooted in plasticity of individual synapses, but rules governing the collective behavior of large networks of neurons are only poorly understood. The postnatal brain growth partly evoked by extensive formation of new synaptic connections may expose cortical areas to a 'natural perturbation' sufficiently strong to observe signatures of large scale reorganization. Quantifying large sets of imaging data from juvenile cat visual cortex, we observe a novel mode of reorganization of domains that prefer inputs from one eye or the other. Our theoretical analysis shows that this mode can be explained quantitatively by the so called Zigzag instability, a dynamical reorganization, well-known in the field of pattern formation in physics, by which 2D isotropic Turing patterns respond to an increase in their typical spatial scale with a zigzag-like bending of domains. We point out that this instability has in fact been predicted, albeit implicitly, by most models of visual cortical development that have been proposed so far. We conclude that cortical networks can undergo large scale reorganizations during normal postnatal development.

  9. Empathy for pain and touch in the human somatosensory cortex.

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    Bufalari, Ilaria; Aprile, Taryn; Avenanti, Alessio; Di Russo, Francesco; Aglioti, Salvatore Maria

    2007-11-01

    Although feeling pain and touch has long been considered inherently private, recent neuroimaging and neurophysiological studies hint at the social implications of this experience. Here we used somatosensory-evoked potentials (SEPs) to investigate whether mere observation of painful and tactile stimuli delivered to a model would modulate neural activity in the somatic system of an onlooker. Viewing video clips showing pain and tactile stimuli delivered to others, respectively, increased and decreased the amplitude of the P45 SEP component that reflects the activity of the primary somatosensory cortex (S1). These modulations correlated with the intensity but not with the unpleasantness of the pain and touch ascribed to the model or the aversion induced in the onlooker by the video clips. Thus, modulation of S1 activity contingent upon observation of others' pain and touch may reflect the mapping of sensory qualities of observed painful and tactile stimuli. Results indicate that the S1 is not only involved in the actual perception of pain and touch but also plays an important role in extracting somatic features from social interactions. PMID:17205974

  10. Pleasant human touch is represented in pregenual anterior cingulate cortex.

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    Lindgren, Lenita; Westling, Göran; Brulin, Christine; Lehtipalo, Stefan; Andersson, Micael; Nyberg, Lars

    2012-02-15

    Touch massage (TM) is a form of pleasant touch stimulation used as treatment in clinical settings and found to improve well-being and decrease anxiety, stress, and pain. Emotional responses reported during and after TM have been studied, but the underlying mechanisms are still largely unexplored. In this study, we used functional magnetic resonance (fMRI) to test the hypothesis that the combination of human touch (i.e. skin-to-skin contact) with movement is eliciting a specific response in brain areas coding for pleasant sensations. The design included four different touch conditions; human touch with or without movement and rubber glove with or without movement. Force (2.5 N) and velocity (1.5 cm/s) were held constant across conditions. The pleasantness of the four different touch stimulations was rated on a visual analog scale (VAS-scale) and human touch was rated as most pleasant, particularly in combination with movement. The fMRI results revealed that TM stimulation most strongly activated the pregenual anterior cingulate cortex (pgACC). These results are consistent with findings showing pgACC activation during various rewarding pleasant stimulations. This area is also known to be activated by both opioid analgesia and placebo. Together with these prior results, our finding furthers the understanding of the basis for positive TM treatment effects. PMID:22100768

  11. Creating Concepts from Converging Features in Human Cortex.

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    Coutanche, Marc N; Thompson-Schill, Sharon L

    2015-09-01

    To make sense of the world around us, our brain must remember the overlapping features of millions of objects. Crucially, it must also represent each object's unique feature-convergence. Some theories propose that an integration area (or "convergence zone") binds together separate features. We report an investigation of our knowledge of objects' features and identity, and the link between them. We used functional magnetic resonance imaging to record neural activity, as humans attempted to detect a cued fruit or vegetable in visual noise. Crucially, we analyzed brain activity before a fruit or vegetable was present, allowing us to interrogate top-down activity. We found that pattern-classification algorithms could be used to decode the detection target's identity in the left anterior temporal lobe (ATL), its shape in lateral occipital cortex, and its color in right V4. A novel decoding-dependency analysis revealed that identity information in left ATL was specifically predicted by the temporal convergence of shape and color codes in early visual regions. People with stronger feature-and-identity dependencies had more similar top-down and bottom-up activity patterns. These results fulfill three key requirements for a neural convergence zone: a convergence result (object identity), ingredients (color and shape), and the link between them. PMID:24692512

  12. Kick with the finger: symbolic actions shape motor cortex excitability.

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    Betti, Sonia; Castiello, Umberto; Sartori, Luisa

    2015-11-01

    A large body of research indicates that observing actions made by others is associated with corresponding motor facilitation of the observer's corticospinal system. However, it is still controversial whether this matching mechanism strictly reflects the kinematics of the observed action or its meaning. To test this issue, motor evoked potentials induced by single-pulse transcranial magnetic stimulation were recorded from hand and leg muscles while participants observed a symbolic action carried out with the index finger, but classically performed with the leg (i.e., a soccer penalty kick). A control condition in which participants observed a similar (but not symbolic) hand movement was also included. Results showed that motor facilitation occurs both in the observer's hand (first dorsal interosseous) and leg (quadriceps femoris) muscles. The present study provides evidence that both the kinematics and the symbolic value of an observed action are able to modulate motor cortex excitability. The human motor system is thus not only involved in mirroring observed actions but is also finely tuned to their symbolic value. PMID:26354677

  13. Flexible neural mechanisms of cognitive control within human prefrontal cortex.

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    Braver, Todd S; Paxton, Jessica L; Locke, Hannah S; Barch, Deanna M

    2009-05-01

    A major challenge in research on executive control is to reveal its functional decomposition into underlying neural mechanisms. A typical assumption is that this decomposition occurs solely through anatomically based dissociations. Here we tested an alternative hypothesis that different cognitive control processes may be implemented within the same brain regions, with fractionation and dissociation occurring on the basis of temporal dynamics. Regions within lateral prefrontal cortex (PFC) were examined that, in a prior study, exhibited contrasting temporal dynamics between older and younger adults during performance of the AX-CPT cognitive control task. The temporal dynamics in younger adults fit a proactive control pattern (primarily cue-based activation), whereas in older adults a reactive control pattern was found (primarily probe-based activation). In the current study, we found that following a period of task-strategy training, these older adults exhibited a proactive shift within a subset of the PFC regions, normalizing their activity dynamics toward young adult patterns. Conversely, under conditions of penalty-based monetary incentives, the younger adults exhibited a reactive shift some of the same regions, altering their temporal dynamics toward the older adult baseline pattern. These experimentally induced crossover patterns of temporal dynamics provide strong support for dual modes of cognitive control that can be flexibly shifted within PFC regions, via modulation of neural responses to changing task conditions or behavioral goals. PMID:19380750

  14. Architecture of explanatory inference in the human prefrontal cortex.

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    Barbey, Aron K; Patterson, Richard

    2011-01-01

    Causal reasoning is a ubiquitous feature of human cognition. We continuously seek to understand, at least implicitly and often explicitly, the causal scenarios in which we live, so that we may anticipate what will come next, plan a potential response and envision its outcome, decide among possible courses of action in light of their probable outcomes, make midstream adjustments in our goal-related activities as our situation changes, and so on. A considerable body of research shows that the lateral prefrontal cortex (PFC) is crucial for causal reasoning, but also that there are significant differences in the manner in which ventrolateral PFC, dorsolateral PFC, and anterolateral PFC support causal reasoning. We propose, on the basis of research on the evolution, architecture, and functional organization of the lateral PFC, a general framework for understanding its roles in the many and varied sorts of causal reasoning carried out by human beings. Specifically, the ventrolateral PFC supports the generation of basic causal explanations and inferences; dorsolateral PFC supports the evaluation of these scenarios in light of some given normative standard (e.g., of plausibility or correctness in light of real or imagined causal interventions); and anterolateral PFC supports explanation and inference at an even higher level of complexity, coordinating the processes of generation and evaluation with further cognitive processes, and especially with computations of hedonic value and emotional implications of possible behavioral scenarios - considerations that are often critical both for understanding situations causally and for deciding about our own courses of action. PMID:21845182

  15. Temporal cortex reflects effects of sentence context on phonetic processing.

    Science.gov (United States)

    Guediche, Sara; Salvata, Caden; Blumstein, Sheila E

    2013-05-01

    Listeners' perception of acoustically presented speech is constrained by many different sources of information that arise from other sensory modalities and from more abstract higher-level language context. An open question is how perceptual processes are influenced by and interact with these other sources of information. In this study, we use fMRI to examine the effect of a prior sentence fragment meaning on the categorization of two possible target words that differ in an acoustic phonetic feature of the initial consonant, VOT. Specifically, we manipulate the bias of the sentence context (biased, neutral) and the target type (ambiguous, unambiguous). Our results show that an interaction between these two factors emerged in a cluster in temporal cortex encompassing the left middle temporal gyrus and the superior temporal gyrus. The locus and pattern of these interactions support an interactive view of speech processing and suggest that both the quality of the input and the potential bias of the context together interact and modulate neural activation patterns. PMID:23281778

  16. Electrical stimulation of the dorsolateral prefrontal cortex improves memory monitoring.

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    Chua, Elizabeth F; Ahmed, Rifat

    2016-05-01

    The ability to accurately monitor one's own memory is an important feature of normal memory function. Converging evidence from neuroimaging and lesion studies have implicated the dorsolateral prefrontal cortex (DLPFC) in memory monitoring. Here we used high definition transcranial direct stimulation (HD-tDCS), a non-invasive form of brain stimulation, to test whether the DLPFC has a causal role in memory monitoring, and the nature of that role. We used a metamemory monitoring task, in which participants first attempted to recall the answer to a general knowledge question, then gave a feeling-of-knowing (FOK) judgment, followed by a forced choice recognition task. When participants received DLPFC stimulation, their feeling-of-knowing judgments were better predictors of memory performance, i.e., they had better memory monitoring accuracy, compared to stimulation of a control site, the anterior temporal lobe (ATL). Effects of DLPFC stimulation were specific to monitoring accuracy, as there was no significant increase in memory performance, and if anything, there was poorer memory performance with DLPFC stimulation. Thus we have demonstrated a causal role for the DLPFC in memory monitoring, and showed that electrically stimulating the left DLPFC led people to more accurately monitor and judge their own memory. PMID:26970142

  17. Functional integration of human neural precursor cells in mouse cortex.

    Directory of Open Access Journals (Sweden)

    Fu-Wen Zhou

    Full Text Available This study investigates the electrophysiological properties and functional integration of different phenotypes of transplanted human neural precursor cells (hNPCs in immunodeficient NSG mice. Postnatal day 2 mice received unilateral injections of 100,000 GFP+ hNPCs into the right parietal cortex. Eight weeks after transplantation, 1.21% of transplanted hNPCs survived. In these hNPCs, parvalbumin (PV-, calretinin (CR-, somatostatin (SS-positive inhibitory interneurons and excitatory pyramidal neurons were confirmed electrophysiologically and histologically. All GFP+ hNPCs were immunoreactive with anti-human specific nuclear protein. The proportions of PV-, CR-, and SS-positive cells among GFP+ cells were 35.5%, 15.7%, and 17.1%, respectively; around 15% of GFP+ cells were identified as pyramidal neurons. Those electrophysiologically and histological identified GFP+ hNPCs were shown to fire action potentials with the appropriate firing patterns for different classes of neurons and to display spontaneous excitatory and inhibitory postsynaptic currents (sEPSCs and sIPSCs. The amplitude, frequency and kinetic properties of sEPSCs and sIPSCs in different types of hNPCs were comparable to host cells of the same type. In conclusion, GFP+ hNPCs produce neurons that are competent to integrate functionally into host neocortical neuronal networks. This provides promising data on the potential for hNPCs to serve as therapeutic agents in neurological diseases with abnormal neuronal circuitry such as epilepsy.

  18. High Stimulus-Related Information in Barrel Cortex Inhibitory Interneurons.

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    Vicente Reyes-Puerta

    2015-06-01

    Full Text Available The manner in which populations of inhibitory (INH and excitatory (EXC neocortical neurons collectively encode stimulus-related information is a fundamental, yet still unresolved question. Here we address this question by simultaneously recording with large-scale multi-electrode arrays (of up to 128 channels the activity of cell ensembles (of up to 74 neurons distributed along all layers of 3-4 neighboring cortical columns in the anesthetized adult rat somatosensory barrel cortex in vivo. Using two different whisker stimulus modalities (location and frequency we show that individual INH neurons--classified as such according to their distinct extracellular spike waveforms--discriminate better between restricted sets of stimuli (≤6 stimulus classes than EXC neurons in granular and infra-granular layers. We also demonstrate that ensembles of INH cells jointly provide as much information about such stimuli as comparable ensembles containing the ~20% most informative EXC neurons, however presenting less information redundancy - a result which was consistent when applying both theoretical information measurements and linear discriminant analysis classifiers. These results suggest that a consortium of INH neurons dominates the information conveyed to the neocortical network, thereby efficiently processing incoming sensory activity. This conclusion extends our view on the role of the inhibitory system to orchestrate cortical activity.

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

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    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. PMID:26936978

  20. Optophysiological analysis of associational circuits in the olfactory cortex

    Directory of Open Access Journals (Sweden)

    Akari eHagiwara

    2012-04-01

    Full Text Available Primary olfactory cortical areas receive direct input from the olfactory bulb, but also have extensive associational connections that have been mainly studied with classical anatomical methods. Here, we shed light on the functional properties of associational connections in the anterior and posterior piriform cortex (aPC and pPC using optophysiological methods. We found that the aPC receives dense functional connections from the anterior olfactory nucleus (AON, a major hub in olfactory cortical circuits. The local recurrent connectivity within the aPC, long invoked in cortical autoassociative models, is sparse and weak. By contrast, the pPC receives negligible input from the AON, but has dense connections from the aPC as well as more local recurrent connections than the aPC. Finally, there are negligible functional connections from the pPC to aPC. Our study provides a circuit basis for a more sensory role for the aPC in odor processing and an associative role for the pPC.

  1. Positive and negative reinforcement activate human auditory cortex

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    Tina Weis

    2013-12-01

    Full Text Available Prior studies suggest that reward modulates neural activity in sensory cortices, but less is known about punishment. We used functional magnetic resonance imaging and an auditory discrimination task, where participants had to judge the duration of frequency modulated tones. In one session correct performance resulted in financial gains at the end of the trial, in a second session incorrect performance resulted in financial loss. Incorrect performance in the rewarded as well as correct performance in the punishment condition resulted in a neutral outcome. The size of gains and losses was either low or high (10 or 50 Euro cent depending on the direction of frequency modulation. We analyzed neural activity at the end of the trial, during reinforcement, and found increased neural activity in auditory cortex when gaining a financial reward as compared to gaining no reward and when avoiding financial loss as compared to receiving a financial loss. This was independent on the size of gains and losses. A similar pattern of neural activity for both gaining a reward and avoiding a loss was also seen in right middle temporal gyrus, bilateral insula and pre-supplemental motor area, here however neural activity was lower after correct responses compared to incorrect responses. To summarize, this study shows that the activation of sensory cortices, as previously shown for gaining a reward is also seen during avoiding a loss.

  2. Surface Reconstruction and Optimization of Cerebral Cortex for Application Use.

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    Shin, Dong Sun; Park, Sang Kyu

    2016-03-01

    For the purposes of virtual surgery, medical education, medical communication, and realistic surface models of anatomic structures are required. In the most involved method, surface models can be made using segmentation and three-dimensional reconstruction procedures. Such models, however, are computationally expensive, and can be difficult to use. Therefore, optimization is often performed manually, but this is a time-consuming job that requires considerable artistic talent. In this article, the authors describe a method that uses Maya and ZBrush to construct optimized surface models of anatomic structures. The authors take 235 anatomic images generated from a cadaver, and perform segmentation and surface reconstruction using Photoshop and Mimics. Reconstructed surface models of the cerebral cortex are then optimized and divided by a morphing technique in Maya and ZBrush for use in medical applications. The optimized surface models do not require significant storage space, and are easily manufactured and modified. The resulting surface models can be displayed off-line and on-line in real time, as well as on smart phones. Using commercial software with the specialized functions described in this study, it is expected that the efficiencies produced by the proposed method will enable researchers to conveniently create surface models from serially sectioned images such as computed tomographs and magnetic resonance images. The surface models created in this research will also have widespread applications in both medical education and communication. PMID:26854785

  3. Cadmium in kidney cortex, liver, and pancreas from Swedish autopsies. Estimation of biological half time in kidney cortex, considering calorie intake and smoking habits.

    Science.gov (United States)

    Elinder, C G; Lind, B; Kjellström, T; Linnman, L; Friberg, L

    1976-01-01

    Cadmium and zinc have been analyzed in tissues from 292 persons autopsied in Stockholm. In kidney cortex, liver, and pancreas the individual cadmium levels are distributed in a lognormal way. In kidney cortex there is a continuous accumulation of cadmium with age up to 50 years, followed by a decrease. Smokers show a higher cadmium accumulation. For nonsmokers, the biological half time of cadmium in kidney cortex is estimated at 30 years, with an average concentration at age 50 of 11 mug/g wet weight. When smokers are included, the average cadmium concentration at age 50 is 22 mug/g wet weight. Based on the more pronounced cadmium accumulation among smokers than nonsmokers, the respiratory absorption rate of cadmium from tobacco smoke is estimated to be approximately 50%. PMID:999342

  4. Cadmium in kidney cortex, liver, and pancreas from Swedish autopsies. Estimation of biological half time in kidney cortex, considering calorie intake and smoking habits

    Energy Technology Data Exchange (ETDEWEB)

    Elinder, C.G. (Karolinska Inst., Stockholm); Kjellstrom, T.; Friberg, L.; Lind, B.; Linnman, L.

    1976-01-01

    Cadmium and zinc have been analyzed in tissues from 292 persons autopsied in Stockholm. In kidney cortex, liver, and pancreas the individual cadmium levels are distributed in a lognormal way. In kidney cortex there is a continuous accumulation of cadmium with age up to 50 years, followed by a decrease. Smokers show a higher cadmium accumulation. For nonsmokers, the biological half time of cadmium in kidney cortex is estimated at 30 years, with an average concentration at age 50 of 11 ..mu..g/g wet weight. When smokers are included, the average cadmium concentration at age 50 is 22 ..mu..g/g wet weight. Based on the more pronounced cadmium accumulation among smokers than nonsmokers, the respiratory absorption rate of cadmium from tobacco smoke is estimated to be approximately 50 percent.

  5. Antibacterial Effect of Granati fructus Cortex Extract on Streptococcus mutans In Vitro

    Directory of Open Access Journals (Sweden)

    Cut R. Alfath

    2013-07-01

    Full Text Available 72 1024x768 The rind of pomegranate fruit (Granati fructus cortex composed of antibacterial compounds such as alkaloid, flavonoid and tannin. Objective: To evaluate the bacterial effect of Granati fructus cortex extract against Streptococcus mutans. Methods: The study was laboratory experimental. The inhibition test was performed by agar diffusion method on MHA medium. Results: It showed the bacterial property of Granati fructus cortex on various concentration. The highest extract concentration of 30% extract has the largest of inhibition zones (15.4mm. The results showed a difference in the size of inhibition zones related to different extract concentrations. Conclusion: This study confirmed the antibacterial effect of Granati fructus cortex on the growth of Streptococcus mutans.DOI: 10.14693/jdi.v20i1.126

  6. Visual Cortex Plasticity Following Peripheral Damage To The Visual System: fMRI Evidence.

    Science.gov (United States)

    Lemos, João; Pereira, Daniela; Castelo-Branco, Miguel

    2016-10-01

    Over the last two decades, functional magnetic resonance imaging (fMRI) has become a powerful research method to investigate cortical visual plasticity. Abnormal fMRI response patterns have been occasionally detected in the visually deprived cortex of patients with bilateral retinal diseases. Controversy remains whether these observations indicate structural reorganization of the visual cortex or unmasking of previously silent cortico-cortical connections. In optic nerve diseases, there is weak evidence showing that early visual cortex seems to lack reorganization, while higher-order visual areas undergo plastic changes which may contribute to optimise visual function. There is however accumulating imaging evidence demonstrating trans-synaptic degeneration of the visual cortex in patients with disease of the anterior visual pathways. This may preclude the use of restorative treatments in these patients. Here, we review and update the body of fMRI evidence on visual cortical plasticity. PMID:27542799

  7. Spontaneous high-gamma band activity reflects functional organization of auditory cortex in the awake macaque.

    Science.gov (United States)

    Fukushima, Makoto; Saunders, Richard C; Leopold, David A; Mishkin, Mortimer; Averbeck, Bruno B

    2012-06-01

    In the absence of sensory stimuli, spontaneous activity in the brain has been shown to exhibit organization at multiple spatiotemporal scales. In the macaque auditory cortex, responses to acoustic stimuli are tonotopically organized within multiple, adjacent frequency maps aligned in a caudorostral direction on the supratemporal plane (STP) of the lateral sulcus. Here, we used chronic microelectrocorticography to investigate the correspondence between sensory maps and spontaneous neural fluctuations in the auditory cortex. We first mapped tonotopic organization across 96 electrodes spanning approximately two centimeters along the primary and higher auditory cortex. In separate sessions, we then observed that spontaneous activity at the same sites exhibited spatial covariation that reflected the tonotopic map of the STP. This observation demonstrates a close relationship between functional organization and spontaneous neural activity in the sensory cortex of the awake monkey. PMID:22681693

  8. Effects of cholinergic deafferentation of the rhinal cortex on visual recognition memory in monkeys

    Science.gov (United States)

    Turchi, Janita; Saunders, Richard C.; Mishkin, Mortimer

    2005-01-01

    Excitotoxic lesion studies have confirmed that the rhinal cortex is essential for visual recognition ability in monkeys. To evaluate the mnemonic role of cholinergic inputs to this cortical region, we compared the visual recognition performance of monkeys given rhinal cortex infusions of a selective cholinergic immunotoxin, ME20.4-SAP, with the performance of monkeys given control infusions into this same tissue. The immunotoxin, which leads to selective cholinergic deafferentation of the infused cortex, yielded recognition deficits of the same magnitude as those produced by excitotoxic lesions of this region, providing the most direct demonstration to date that cholinergic activation of the rhinal cortex is essential for storing the representations of new visual stimuli and thereby enabling their later recognition. PMID:15684066

  9. Dual streams of auditory afferents target multiple domains in the primate prefrontal cortex

    Science.gov (United States)

    Romanski, L. M.; Tian, B.; Fritz, J.; Mishkin, M.; Goldman-Rakic, P. S.; Rauschecker, J. P.

    2009-01-01

    ‘What’ and ‘where’ visual streams define ventrolateral object and dorsolateral spatial processing domains in the prefrontal cortex of nonhuman primates. We looked for similar streams for auditory–prefrontal connections in rhesus macaques by combining microelectrode recording with anatomical tract-tracing. Injection of multiple tracers into physiologically mapped regions AL, ML and CL of the auditory belt cortex revealed that anterior belt cortex was reciprocally connected with the frontal pole (area 10), rostral principal sulcus (area 46) and ventral prefrontal regions (areas 12 and 45), whereas the caudal belt was mainly connected with the caudal principal sulcus (area 46) and frontal eye fields (area 8a). Thus separate auditory streams originate in caudal and rostral auditory cortex and target spatial and non-spatial domains of the frontal lobe, respectively. PMID:10570492

  10. Postoperative increase in grey matter volume in visual cortex after unilateral cataract surgery

    DEFF Research Database (Denmark)

    Lou, Astrid R.; Madsen, Kristoffer Hougaard; Julian, Hanne O.;

    2013-01-01

    more symmetrical visual acuity became after unilateral cataract surgery, the more pronounced was the grey matter increase in visual cortex. Conclusion:  The data suggest that cataract surgery triggered a use-dependent structural plasticity in V2 presumably through improved binocular integration of......Purpose:  The developing visual cortex has a strong potential to undergo plastic changes. Little is known about the potential of the ageing visual cortex to express plasticity. A pertinent question is whether therapeutic interventions can trigger plastic changes in the ageing visual cortex by...... restoring vision. Methods:  Twelve patients aged 50–85 years underwent structural high-resolution T1-weighted MRI of the whole brain 2 days and 6 weeks after unilateral cataract surgery. Voxel-based morphometry (VBM) based on T1-weighted magnetic resonance imaging (MRI) was employed to test whether cataract...

  11. Activation of visual cortex in REM sleep measured by 24-channel NIRS imaging.

    Science.gov (United States)

    Igawa, M; Atsumi, Y; Takahashi, K; Shiotsuka, S; Hirasawa, H; Yamamoto, R; Maki, A; Yamashita, Y; Koizumi, H

    2001-06-01

    To visualize dreaming brain functions we studied hemodynamic changes in the visual cortex during the transition from non-rapid eye movement (NREM) to rapid eye movement (REM) sleep, using a 24-channel Near-Infrared Spectroscopy (NIRS) imaging method. Results were compared to the activation in visual cortex by visual stimulation during wakefulness. Subjects were four healthy males between 25 and 49 years of age. Five all-night polysomnographic and NIRS recordings were made. Increases in the oxygenated hemoglobin concentration in visual cortex were observed from nine of 14 REM periods. The activated areas were broader during REM sleep than during visual stimulation. These findings suggest that activation of visual cortex in REM sleep might represent dream-related brain activity. PMID:11422835

  12. Cognitive Functions of the Posterior Parietal Cortex: Top-down and bottom-up attentional control

    Directory of Open Access Journals (Sweden)

    Sarah Shomstein

    2012-07-01

    Full Text Available Although much less is known about human parietal cortex than that of homologous monkey cortex, recent studies, employing neuroimaging and neuropsychological methods, have begun to elucidate increasingly fine-grained functional and structural distinctions.\tThis review is focused on recent neuroimaging and neuropsychological studies elucidating the cognitive roles of dorsal and ventral regions of parietal cortex in top-down and bottom-up attentional orienting, and on the interaction between the two attentional allocation mechanisms. Evidence is reviewed arguing that regions along the dorsal areas of the parietal cortex, including the superior parietal lobule (SPL are involved in top-down attentional orienting, while ventral regions including the temporo-parietal junction (TPJ are involved in bottom-up attentional orienting.

  13. Systematic Regional Variations of GABA, Glutamine, and Glutamate Concentrations Follow Receptor Fingerprints of Human Cingulate Cortex

    NARCIS (Netherlands)

    Dou, Weiqiang; Palomero-Gallagher, Nicola; van Tol, Marie-Jose; Kaufmann, Joern; Zhong, Kai; Bernstein, Hans-Gert; Heinze, Hans-Jochen; Speck, Oliver; Walter, Martin

    2013-01-01

    Magnetic resonance spectroscopy (MRS) of glutamatergic or GABAergic measures in anterior cingulate cortex (ACC) was found altered in psychiatric disorders and predictive of interindividual variations of functional responses in healthy populations. Several ACC subregions have been parcellated into re

  14. Effects of Dimethyl Sulfoxide on Neuronal Response Characteristics in Deep Layers of Rat Barrel Cortex

    Science.gov (United States)

    Soltani, Narjes; Mohammadi, Elham; Allahtavakoli, Mohammad; Shamsizadeh, Ali; Roohbakhsh, Ali; Haghparast, Abbas

    2016-01-01

    Introduction: Dimethyl sulfoxide (DMSO) is a chemical often used as a solvent for water-insoluble drugs. In this study, we evaluated the effect of intracerebroventricular (ICV) administration of DMSO on neural response characteristics (in 1200–1500 μm depth) of the rat barrel cortex. Methods: DMSO solution was prepared in 10% v/v concentration and injected into the lateral ventricle of rats. Neuronal spontaneous activity and neuronal responses to deflection of the principal whisker (PW) and adjacent whisker (AW) were recorded in barrel cortex. A condition test ratio (CTR) was used to measure inhibitory receptive fields in barrel cortex. Results: The results showed that both PW and AW evoked ON and OFF responses, neuronal spontaneous activity and inhibitory receptive fields did not change following ICV administration of DMSO. Conclusion: Results of this study suggest that acute ICV administration of 10% DMSO did not modulate the electrophysiological characteristics of neurons in the l deep ayers of rat barrel cortex.

  15. Large-Scale Functional Reorganization in Adult Monkey Cortex after Peripheral Nerve Injury

    Science.gov (United States)

    Garraghty, Preston E.; Kaas, Jon H.

    1991-08-01

    In adult monkeys, peripheral nerve injuries induce dramatic examples of neural plasticity in somatosensory cortex. It has been suggested that a cortical distance limit exists and that the amount of plasticity that is possible after injury is constrained by this limit. We have investigated this possibility by depriving a relatively large expanse of cortex by transecting and ligating both the median and the ulnar nerves to the hand. Electrophysiological recording in cortical areas 3b and 1 in three adult squirrel monkeys no less than 2 months after nerve transection has revealed that cutaneous responsiveness is regained throughout the deprived cortex and that a roughly normal topographic order is reestablished for the reorganized cortex.

  16. Virtual reality and the role of the prefrontal cortex in adults and children.

    Directory of Open Access Journals (Sweden)

    Lutz Jäncke

    2009-05-01

    Full Text Available In this review the neural underpinnings of the experience of presence are outlined. Firstly, it will be shown that presence is associated with an activation of a distributed network including the dorsal and ventral visual stream, the parietal cortex, the premotor cortex, mesial temporal areas, the brainstem and the thalamus. Second, the dorsolateral prefrontal cortex (DLPFC is identified as a key node of this network in that it modulates the activity of this network and the associated experience of presence. Third, because of their unmatured frontal cortex, children lack the strong modulatory influence of the DLPFC on this network. Fourth, it is shown that by manipulating the activation in the DLPFC using transcranial direct current stimulation (tDCS while participants are exposed to the virtual roller coaster ride presence-related measures are influenced. Finally, these findings are discussed in the context of current models explaining the experience of presence, the rubber hand illusion, and out of body experiences.

  17. 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.

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

    Science.gov (United States)

    Winter, Mark R; Liu, Mo; Monteleone, David; Melunis, Justin; Hershberg, Uri; Goderie, Susan K; Temple, Sally; Cohen, Andrew R

    2015-10-13

    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. PMID:26344906

  19. Morphology of Pyramidal Neurons in the Rat Prefrontal Cortex: Lateralized Dendritic Remodeling by Chronic Stress

    Directory of Open Access Journals (Sweden)

    Claudia Perez-Cruz

    2007-01-01

    Full Text Available The prefrontal cortex (PFC plays an important role in the stress response. We filled pyramidal neurons in PFC layer III with neurobiotin and analyzed dendrites in rats submitted to chronic restraint stress and in controls. In the right prelimbic cortex (PL of controls, apical and distal dendrites were longer than in the left PL. Stress reduced the total length of apical dendrites in right PL and abolished the hemispheric difference. In right infralimbic cortex (IL of controls, proximal apical dendrites were longer than in left IL, and stress eliminated this hemispheric difference. No hemispheric difference was detected in anterior cingulate cortex (ACx of controls, but stress reduced apical dendritic length in left ACx. These data demonstrate interhemispheric differences in the morphology of pyramidal neurons in PL and IL of control rats and selective effects of stress on the right hemisphere. In contrast, stress reduced dendritic length in the left ACx.

  20. Facilitated lexical ambiguity processing by transcranial direct current stimulation over the left inferior frontal cortex.

    Science.gov (United States)

    Ihara, Aya S; Mimura, Takanori; Soshi, Takahiro; Yorifuji, Shiro; Hirata, Masayuki; Goto, Tetsu; Yoshinime, Toshiki; Umehara, Hiroaki; Fujimaki, Norio

    2015-01-01

    Previous studies suggest that the left inferior frontal cortex is involved in the resolution of lexical ambiguities for language comprehension. In this study, we hypothesized that processing of lexical ambiguities is improved when the excitability of the left inferior frontal cortex is enhanced. To test the hypothesis, we conducted an experiment with transcranial direct current stimulation (tDCS). We investigated the effect of anodal tDCS over the left inferior frontal cortex on behavioral indexes for semantic judgment on lexically ambiguous and unambiguous words within a context. Supporting the hypothesis, the RT was shorter in the anodal tDCS session than in the sham session for ambiguous words. The results suggest that controlled semantic retrieval and contextual selection were facilitated by anodal tDCS over the left inferior frontal cortex. PMID:25208744

  1. Right and left visual cortex areas in healthy subjects with right- and left-eye dominance.

    Science.gov (United States)

    Erdoğan, A Riza; Ozdikici, Mete; Aydin, M Dumlu; Aktaş, Omer; Dane, Senol

    2002-05-01

    The aim of this work was to study the differences between the right- and left-visual cortices in relation to eyedness in healthy subjects. Ocular dominance was determined by means of the near-far alignment test. To assess visual cortical areas, the right and left sagittal scenograms of cranium by magnetic resonance imaging were used. To calculate the visual cortex areas by using scenograms, Cavalieri's method was used. In the subjects with right-eye dominance, the right visual cortex was larger than the left visual cortex, and vice versa in the subjects with left-eye dominance. The right and left cuneal areas were found to be larger in males than in females. In light of these results, it was concluded that the human eyes are predominantly controlled by the ipsilateral visual cortex. PMID:12325387

  2. Disassembled DJ-1 high molecular weight complex in cortex mitochondria from Parkinson's disease patients

    OpenAIRE

    Adler Charles; Sue Lucia; Beach Thomas; Civarella Gina; He Ping; Nural Hikmet; Zhong Zhenyu; Shill Holly; Caviness John; Xia Weiming; Shen Yong

    2009-01-01

    Abstract Correction to Nural H, He P, Beach T, Sue L, Xia W, Shen Y. Disassembled DJ-1 high molecular weight complex in cortex mitochondria from Parkinson's disease patients Molecular Neurodegeneration 2009, 4:23.

  3. Disassembled DJ-1 high molecular weight complex in cortex mitochondria from Parkinson's disease patients

    Directory of Open Access Journals (Sweden)

    Adler Charles

    2009-07-01

    Full Text Available Abstract Correction to Nural H, He P, Beach T, Sue L, Xia W, Shen Y. Disassembled DJ-1 high molecular weight complex in cortex mitochondria from Parkinson's disease patients Molecular Neurodegeneration 2009, 4:23.

  4. Evidence for functional abnormality in the right auditory cortex during musical hallucinations.

    Science.gov (United States)

    Kasai, K; Asada, T; Yumoto, M; Takeya, J; Matsuda, H

    1999-11-13

    Right auditory cortex dysfunction during musical hallucinations occurred in an 88-year-old woman, who was otherwise cognitively intact. We assessed this phenomenon with a combination of neuromagnetic and cerebral blood-flow measurements. PMID:10568580

  5. Reduced Numbers of Somatostatin Receptors in the Cerebral Cortex in Alzheimer's Disease

    Science.gov (United States)

    Flint Beal, M.; Mazurek, Michael F.; Tran, Vinh T.; Chattha, Geetinder; Bird, Edward D.; Martin, Joseph B.

    1985-07-01

    Somatostatin receptor concentrations were measured in patients with Alzheimer's disease and controls. In the frontal cortex (Brodmann areas 6, 9, and 10) and temporal cortex (Brodmann area 21), the concentrations of somatostatin in receptors in the patients were reduced to approximately 50 percent of control values. A 40 percent reduction was seen in the hippocampus, while no significant changes were found in the cingulate cortex, postcentral gyrus, temporal pole, and superior temporal gyrus. Scatchard analysis showed a reduction in receptor number rather than a change in affinity. Somatostatin-like immunoreactivity was significantly reduced in both the frontal and temporal cortex. Somatostatin-like immunoreactivity was linearly related to somatostatin-receptor binding in the cortices of Alzheimer's patients. These findings may reflect degeneration of postsynaptic neurons or cortical afferents in the patients' cerebral cortices. Alternatively, decreased somatostatinlike immunoreactivity in Alzheimer's disease might indicate increased release of somatostatin and down regulation of postsynaptic receptors.

  6. Sensory Responses during Sleep in Primate Primary and Secondary Auditory Cortex

    OpenAIRE

    Issa, Elias B.; Wang, Xiaoqin

    2008-01-01

    Most sensory stimuli do not reach conscious perception during sleep. It has been thought that the thalamus prevents the relay of sensory information to cortex during sleep, but the consequences for cortical responses to sensory signals in this physiological state remain unclear. We recorded from two auditory cortical areas downstream of the thalamus in naturally sleeping marmoset monkeys. Single neurons in primary auditory cortex either increased or decreased their responses during sleep comp...

  7. Evidence for reduced experience-dependent dendritic spine plasticity in the aging prefrontal cortex

    OpenAIRE

    Bloss, Erik B.; Janssen, William G.; Ohm, Daniel T.; Yuk, Frank J; Wadsworth, Shannon; Saardi, Karl M.; Bruce S McEwen; Morrison, John H.

    2011-01-01

    Cognitive functions that require the prefrontal cortex are highly sensitive to aging in humans, non-human primates, and rodents, although the neurobiological correlates of this vulnerability remain largely unknown. It has been proposed that dendritic spines represent the primary site of structural plasticity in the adult brain, and recent data have supported the hypothesis that aging is associated with alterations of dendritic spine morphology and plasticity in prefrontal cortex. However, no ...

  8. Model for probing membrane-cortex adhesion by micropipette aspiration and fluctuation spectroscopy

    OpenAIRE

    Alert, Ricard; Casademunt, Jaume; Brugués, Jan; Sens, Pierre

    2016-01-01

    We propose a model for membrane-cortex adhesion that couples membrane deformations, hydrodynamics, and kinetics of membrane-cortex ligands. In its simplest form, the model gives explicit predictions for the critical pressure for membrane detachment and for the value of adhesion energy. We show that these quantities exhibit a significant dependence on the active acto-myosin stresses. The model provides a simple framework to access quantitative information on cortical activity by means of micro...

  9. The human vestibular cortex revealed by coordinate-based activation likelihood estimation meta-analysis

    OpenAIRE

    Lopez, C.; O. Blanke; Mast, F. W.

    2012-01-01

    The vestibular system contributes to the control of posture and eye movements and is also involved in various cognitive functions including spatial navigation and memory. These functions are subtended by projections to a vestibular cortex, whose exact location in the human brain is still a matter of debate (Lopez and Blanke, 2011). The vestibular cortex can be defined as the network of all cortical areas receiving inputs from the vestibular system, including areas where vestibular signals inf...

  10. Impaired Error-Likelihood Prediction in Medial Prefrontal Cortex in Schizophrenia

    OpenAIRE

    Krawitz, Adam; Braver, Todd S.; Barch, Deanna M.; Brown, Joshua W.

    2010-01-01

    The cognitive impairment in individuals with schizophrenia includes deficits of working memory in dorsolateral prefrontal cortex and deficits of performance monitoring in medial prefrontal cortex (MPFC). Recent work suggests a more general role for MPFC in predicting the outcome of actions and then evaluating those predictions. Here we investigate, in individuals with schizophrenia, two specific effects associated with this role: the error likelihood effect (occurring on trials with correct p...

  11. Does Cell Lineage in the Developing Cerebral Cortex Contribute to its Columnar Organization?

    OpenAIRE

    Costa, Marcos R.; Cecilia Hedin-Pereira

    2010-01-01

    Since the pioneer work of Lorente de Nó, Ramón y Cajal, Brodmann, Mountcastle, Hubel and Wiesel and others, the cerebral cortex has been seen as a jigsaw of anatomic and functional modules involved in the processing of different sets of information. In fact, a columnar distribution of neurons displaying similar functional properties throughout the cerebral cortex has been observed by many researchers. Although it has been suggested that much of the anatomical substrate for such ...

  12. Retinoic acid influences neuronal migration from the ganglionic eminence to the cerebral cortex

    OpenAIRE

    Crandall, James E.; Goodman, Timothy; McCarthy, Deirdre M.; Duester, Gregg; Bhide, Pradeep G.; Dräger, Ursula C.; McCaffery, Peter

    2011-01-01

    The ganglionic eminence contributes cells to several forebrain structures including the cerebral cortex, for which it provides GABAergic interneurons. Migration of neuronal precursors from the retinoic-acid rich embryonic ganglionic eminence to the cerebral cortex is known to be regulated by several factors, but retinoic acid has not been previously implicated. We found retinoic acid to potently inhibit cell migration in slice preparations of embryonic mouse forebrains, which was reversed by ...

  13. Local Circuit Inhibition in the Cerebral Cortex as the source of Gain Control and Untuned Suppression

    OpenAIRE

    Shapley, Robert M.; Xing, Dajun

    2012-01-01

    Theoretical considerations have led to the concept that the cerebral cortex is operating in a balanced state in which synaptic excitation is approximately balanced by synaptic inhibition from the local cortical circuit. This paper is about the functional consequences of the balanced state in sensory cortex. One consequence is gain control: there is experimental evidence and theoretical support for the idea that local circuit inhibition acts as a local automatic gain control throughout the cor...

  14. Evolutionary appearance of von Economo’s neurons in the mammalian cerebral cortex

    OpenAIRE

    Alessandro Vercelli

    2014-01-01

    von Economo’s neurons (VENs) are large, spindle-shaped projection neurons in layer V of the frontoinsular (FI) cortex, and the anterior cingulate cortex. During human ontogenesis, the VENs can first be differentiated at late stages of gestation, and increase in number during the first eight postnatal months. VENs have been identified in humans, chimpanzee, bonobos, gorillas, orangutan and, more recently, in the macaque. Their distribution in great apes seems to correlate with human-like socia...

  15. Upper cortex anatomy corroborates phylogenetic hypothesis in species of Physconia (Ascomycota, Lecanoromycetes).

    Science.gov (United States)

    Divakar, Pradeep K; Amo De Paz, Guillermo; Del Prado, Ruth; Esslinger, Theodore L; Crespo, Ana

    2007-11-01

    A phylogenetic and taxonomic study of the Physconia distorta morphotype complex was undertaken using ITS nu-rDNA as a molecular marker to re-evaluate this group. The analysis incorporated several samples of European P. distorta and also of American and European populations, recently named as P. americana. The phylogenetic analysis revealed that P. distorta and the European population of P. americana form two monophyletic and partially sympatric species and that both are distinct from the American species P. americana. Because differences in upper cortex anatomy had been used in establishing P. americana as distinct from P. distorta, the anatomy of the upper cortex was restudied in all three of these taxa, and notable differences were revealed. Our study confirmed that the upper cortex of P. distorta is prosoplectenchymatous with thick hyphal cell walls and narrow lumina, and that American specimens of P. americana have a typical paraplectenchymatous upper cortex. The cortex anatomy of both of these looks essentially the same in both longitudinal and transverse sections. Conversely, the European specimens that have been called P. americana are different from both of these. The cells of the upper cortex are rather thin walled, and in transverse lobe sections the cortex closely resembles a paraplectenchyma. However, in longitudinal lobe sections these thin walled cells can be seen to be elongate and ramified, obviously hyphal in nature, and better meeting the criteria of a prosoplectenchyma. The results confirmed the evolutionary pattern and taxonomic assessment of the anatomy of the upper cortex in the genus Physconia and revealed a common undescribed species (P. thorstenii sp. nov.) that can be added to the North African and Southern Euro-Asiatic lichen flora. PMID:18023166

  16. Role of the Perigenual Anterior Cingulate and Orbitofrontal Cortex in Contingency Learning in the Marmoset

    OpenAIRE

    Jackson, Stacey A. W.; Pears, Andrew; Horst, Nicole K.; Robbins, Trevor W.; Roberts, Angela C.

    2016-01-01

    Two learning mechanisms contribute to decision-making: goal-directed actions and the “habit” system, by which action-outcome and stimulus-response associations are formed, respectively. Rodent lesion studies and human neuroimaging have implicated both the medial prefrontal cortex (mPFC) and the orbitofrontal cortex (OFC) in the neural basis of contingency learning, a critical component of goal-directed actions, though some published findings are conflicting. We sought to reconcile the existin...

  17. Rat whisker motor cortex is subdivided into sensory-input and motor-output areas

    OpenAIRE

    Smith, Jared B.; Alloway, Kevin D.

    2013-01-01

    Rodent whisking is an exploratory behavior that can be modified by sensory feedback. Consistent with this, many whisker-sensitive cortical regions project to agranular motor [motor cortex (MI)] cortex, but the relative topography of these afferent projections has not been established. Intracortical microstimulation (ICMS) evokes whisker movements that are used to map the functional organization of MI, but no study has compared the whisker-related inputs to MI with the ICMS sites that evoke wh...

  18. Sexual dimorphism and laterality in the evolution of the primate prefrontal cortex

    OpenAIRE

    Smaers, J. B.; Mulvaney, P.I.; Soligo, C.I.; Zilles, K.; Amunts, K.

    2012-01-01

    Social selective pressures are commonly considered as the main driving force of primate brain evolution. Primate social behaviour is, however, known to be sexually dimorphic, and no previous study has made a direct comparison between male and female brain structures across species. We quantify sex-specific evolutionary trends in the prefrontal cortex of anthropoid primates (including humans) to investigate how sexual selection has shaped brain evolution in primates. The prefrontal cortex is o...

  19. Control of Intermale Aggression by Medial Prefrontal Cortex Activation in the Mouse

    OpenAIRE

    Aki Takahashi; Kazuki Nagayasu; Naoya Nishitani; Shuji Kaneko; Tsuyoshi Koide

    2014-01-01

    Aggressive behavior is widely observed throughout the animal kingdom because of its adaptiveness for social animals. However, when aggressive behavior exceeds the species-typical level, it is no longer adaptive, so there should be a mechanism to control excessive aggression to keep it within the adaptive range. Using optogenetics, we demonstrate that activation of excitatory neurons in the medial prefrontal cortex (mPFC), but not the orbitofrontal cortex (OFC), inhibits inter-male aggression ...

  20. Cellular scaling rules for the brain of Artiodactyla include a highly folded cortex with few neurons

    Directory of Open Access Journals (Sweden)

    Rodrigo eSiqueira Kazu

    2014-11-01

    Full Text Available Quantitative analysis of the cellular composition of rodent, primate, insectivore and afrotherian brains has shown that nonneuronal scaling rules are similar across these mammalian orders that diverged about 95 million years ago, and therefore appear to be conserved in evolution, while neuronal scaling rules appear to be free to vary in a clade-specific manner. Here we analyze the cellular scaling rules that apply to the brain of artiodactyls, a group within the order Cetartiodactyla, believed to be a relatively recent radiation from the common Eutherian ancestor. We find that artiodactyls share nonneuronal scaling rules with all groups analyzed previously. Artiodactyls share with afrotherians and rodents, but not with primates, the neuronal scaling rules that apply to the cerebral cortex and cerebellum. The neuronal scaling rules that apply to the remaining brain areas are however distinct in artiodactyls. Importantly, we show that the folding index of the cerebral cortex scales with the number of neurons in the cerebral cortex in distinct fashions across artiodactyls, afrotherians, rodents, and primates, such that the artiodactyl cerebral cortex is more convoluted than primate cortices of similar numbers of neurons. Our findings suggest that the scaling rules found to be shared across modern afrotherians, glires and artiodactyls applied to the common Eutherian ancestor, such as the relationship between the mass of the cerebral cortex as a whole and its number of neurons. In turn, the distribution of neurons along the surface of the cerebral cortex, which is related to its degree of gyrification, appears to be a clade-specific characteristic. If the neuronal scaling rules for artiodactyls extend to all cetartiodactyls, we predict that the large cerebral cortex of cetaceans will still have fewer neurons than the human cerebral cortex.

  1. Parcellation in Left Lateral Parietal Cortex Is Similar in Adults and Children

    OpenAIRE

    Barnes, Kelly Anne; Nelson, Steven M.; Cohen, Alexander L.; Power, Jonathan D.; Coalson, Rebecca S.; Miezin, Francis M.; Vogel, Alecia C.; Dubis, Joseph W.; Church, Jessica A.; Petersen, Steven E.; Schlaggar, Bradley L.

    2011-01-01

    A key question in developmental neuroscience involves understanding how and when the cerebral cortex is partitioned into distinct functional areas. The present study used functional connectivity MRI mapping and graph theory to identify putative cortical areas and generate a parcellation scheme of left lateral parietal cortex (LLPC) in 7 to 10-year-old children and adults. Results indicated that a majority of putative LLPC areas could be matched across groups (mean distance between matched are...

  2. Transcranial magnetic stimulation over human secondary somatosensory cortex disrupts perception of pain intensity

    OpenAIRE

    Lockwood P.L.; Iannetti G.D.; Haggard P.

    2013-01-01

    Pain is a complex sensory experience resulting from the activity of a network of brain regions. However, the functional contribution of individual regions in this network remains poorly understood. We delivered single-pulse transcranial magnetic stimulation (TMS) to the contralateral primary somatosensory cortex (S1), secondary somatosensory cortex (S2) and vertex (control site) 120 msec after selective stimulation of nociceptive afferents using neodymium:yttrium-aluminium-perovskite (Nd:YAP)...

  3. Dissociation of Detection and Discrimination of Pure Tones following Bilateral Lesions of Auditory Cortex

    OpenAIRE

    Andrew R Dykstra; Christine K Koh; Braida, Louis D.; Tramo, Mark Jude

    2012-01-01

    It is well known that damage to the peripheral auditory system causes deficits in tone detection as well as pitch and loudness perception across a wide range of frequencies. However, the extent to which to which the auditory cortex plays a critical role in these basic aspects of spectral processing, especially with regard to speech, music, and environmental sound perception, remains unclear. Recent experiments indicate that primary auditory cortex is necessary for the normally-high perceptual...

  4. Altered Functional Connectivity of the Insular Cortex across Prefrontal Networks in Cocaine Addiction

    OpenAIRE

    Cisler, Josh M.; Elton, Amanda; Kennedy, Ashley P.; Young, Jonathan; Smitherman, Sonet; James, George Andrew; Kilts, Clinton D

    2013-01-01

    Interoception is theorized to be an important process mediating substance use disorders, and the insular cortex is recognized as a core neural region supporting interoception. The purpose of this study was to compare the integration of the insular cortex into prefrontal-related resting-state networks between individuals with cocaine dependence and healthy controls. 41 participants with cocaine dependence and 19 control participants underwent a resting-state 3T fMRI scan. Individuals with coca...

  5. Development of abstract thinking during childhood and adolescence: The role of rostrolateral prefrontal cortex

    OpenAIRE

    Iroise Dumontheil

    2014-01-01

    Rostral prefrontal cortex (RPFC) has increased in size and changed in terms of its cellular organisation during primate evolution. In parallel emerged the ability to detach oneself from the immediate environment to process abstract thoughts and solve problems and to understand other individuals’ thoughts and intentions. Rostrolateral prefrontal cortex (RLPFC) is thought to play an important role in supporting the integration of abstract, often self-generated, thoughts. Thoughts can be tempora...

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

    OpenAIRE

    Pinto, Joshua G. A.; Murphy, Kathryn M.

    2010-01-01

    Functional maturation of visual cortex is linked with dynamic changes in synaptic expression of GABAergic mechanisms. These include setting the excitation-inhibition balance required for experience-dependent plasticity, as well as, intracortical inhibition underlying development and aging of receptive field properties. Animal studies have shown developmental regulation of GABAergic mechanisms in visual cortex. In this study, we show for the first time how these mechanisms develop in the hum...

  7. Cocaine-induced reduction of brain neuropeptide Y synthesis dependent on medial prefrontal cortex.

    OpenAIRE

    Wahlestedt, C; Karoum, F; Jaskiw, G; Wyatt, R. J.; Larhammar, D; Ekman, R.; Reis, D J

    1991-01-01

    Repeated administration of cocaine elicits substantial, long-lasting, but reversible reductions in neuropeptide Y (NPY) and NPY mRNA in the rat cerebral cortex and nucleus accumbens. The NPY reduction appears to be mediated through a decrease in NPY biosynthesis, occurring transneuronally, perhaps in response to changes in synaptic dopamine associated with mesolimbic and mesocortical dopamine neurons. The medial prefrontal cortex appears necessary for maintenance of cocaine's action on this n...

  8. A semi-persistent adult ocular dominance plasticity in visual cortex is stabilized by activated CREB

    OpenAIRE

    Pham, Tony A.; Graham, Sarah J.; Suzuki, Seigo; Barco, Angel; Kandel, Eric R.; Gordon, Barbara; Lickey, Marvin E.

    2004-01-01

    The adult cerebral cortex can adapt to environmental change. Using monocular deprivation as a paradigm, we find that rapid experience-dependent plasticity exists even in the mature primary visual cortex. However, adult cortical plasticity differs from developmental plasticity in two important ways. First, the effect of adult, but not juvenile monocular deprivation is strongly suppressed by administration of barbiturate just prior to recording visual evoked potentials, suggesting that the effe...

  9. Associative fear learning enhances sparse network coding in primary sensory cortex

    OpenAIRE

    Gdalyahu, Amos; Tring, Elaine; Polack, Pierre-Olivier; Gruver, Robin; Golshani, Peyman; Fanselow, Michael S.; Silva, Alcino J.; Trachtenberg, Joshua T.

    2012-01-01

    Several models of associative learning predict that stimulus processing changes during association formation. How associative learning reconfigures neural circuits in primary sensory cortex to "learn" associative attributes of a stimulus remains unknown. Using 2-photon in-vivo calcium imaging to measure responses of networks of neurons in primary somatosensory cortex, we discovered that associative fear learning, in which whisker stimulation is paired with foot shock, enhances sparse populati...

  10. GluA1 Phosphorylation Contributes to Postsynaptic Amplification of Neuropathic Pain in the Insular Cortex

    OpenAIRE

    Qiu, Shuang; Zhang, Ming; Yan LIU; Guo, Yanyan; Zhao, Huan; Song, Qian; Zhao, Minggao; Huganir, Richard L.; Luo, Jianhong; Xu, Hui; Zhuo, Min

    2014-01-01

    Long-term potentiation of glutamatergic transmission has been observed after physiological learning or pathological injuries in different brain regions, including the spinal cord, hippocampus, amygdala, and cortices. The insular cortex is a key cortical region that plays important roles in aversive learning and neuropathic pain. However, little is known about whether excitatory transmission in the insular cortex undergoes plastic changes after peripheral nerve injury. Here, we found that peri...

  11. Roles of the Insular Cortex in the Modulation of Pain: Insights from Brain Lesions

    OpenAIRE

    Starr, Christopher J.; Sawaki, Lumy; Wittenberg, George F.; Burdette, Jonathan H.; Oshiro, Yoshitetsu; Quevedo, Alexandre S.; Coghill, Robert C.

    2009-01-01

    Subjective sensory experiences are constructed by the integration of afferent sensory information with information about the uniquely personal internal cognitive state. The insular cortex is anatomically positioned to serve as one potential interface between afferent processing mechanisms and more cognitively-oriented modulatory systems. However, the role of the insular cortex in such modulatory processes remain poorly understood. Two individuals with extensive lesions to the insula were exam...

  12. State- and trait-related alterations of motor cortex excitability in tinnitus patients

    OpenAIRE

    Schecklmann, Martin; Landgrebe, Michael; Kleinjung, Tobias; Frank, Elmar; Rupprecht, Rainer; Sand, Philipp G.; Eichhammer, Peter; Hajak, Göran; Langguth, Berthold

    2014-01-01

    Chronic tinnitus is a brain network disorder with involvement of auditory and non-auditory areas. Repetitive transcranial magnetic stimulation (rTMS) over the temporal cortex has been investigated for the treatment of tinnitus. Several small studies suggest that motor cortex excitability is altered in people with tinnitus. We retrospectively analysed data from 231 patients with chronic tinnitus and 120 healthy controls by pooling data from different studies. Variables of interest were resting...

  13. Visual cortex as a depth computer: Grossberg's LAMINART or how we see the world in depth

    OpenAIRE

    Dresp, Birgitta

    2014-01-01

    The laminar structure of cortex was first described by Ramón y Cajal (1899). It consists of six different layers, each containing a characteristic distribution of neurons and cell types connecting with other cortical and sub-cortical regions. These extensive connections form microcircuits that group into functionally distinct columns (e.g. Mountcastle, 1997). To account for the Venetian Blind Effect, Cao and Grossberg propose a model which exploits the functional organization of visual cortex...

  14. Model-based analysis of pattern motion processing in mouse primary visual cortex

    OpenAIRE

    Muir, Dylan R.; Roth, Morgane M.; Helmchen, Fritjof; Kampa, Björn M.

    2015-01-01

    Neurons in sensory areas of neocortex exhibit responses tuned to specific features of the environment. In visual cortex, information about features such as edges or textures with particular orientations must be integrated to recognize a visual scene or object. Connectivity studies in rodent cortex have revealed that neurons make specific connections within sub-networks sharing common input tuning. In principle, this sub-network architecture enables local cortical circuits to integrate sensory...

  15. Dynamic modulation of short term synaptic plasticity in the auditory cortex: the role of norepinephrine

    OpenAIRE

    Humberto, Salgado; Francisco, García-Oscos; Lu, Dinh; Marco, Atzori

    2010-01-01

    Norepinephrine (NE) is an important modulator of neuronal activity in the auditory cortex. Using patch-clamp recording and a pair pulse protocol on an auditory cortex slice preparation we recently demonstrated that NE affects cortical inhibition in a layer-specific manner, by decreasing apical but increasing basal inhibition onto layer II/III pyramidal cell dendrites. In the present study we used a similar protocol to investigate the dependence of noradrenergic modulation of inhibition on sti...

  16. Stimulation of the Prelimbic Cortex Differentially Modulates Neuroendocrine Responses to Psychogenic and Systemic Stressors

    OpenAIRE

    Jones, Kenneth R.; Myers, Brent; Herman, James P.

    2011-01-01

    The medial prefrontal cortex is important for normal regulation of stress responses, and is implicated in stress-related affective disease states (e.g. depression). In the current study, we investigated the role of the prelimbic division of the prefrontal cortex in control of responses to psychogenic and systemic stressors (restraint and hypoxia, respectively). Acute stimulation of the prelimbic cortical region with bicuculline methiodide (BMI) caused significant reduction of ACTH and cortico...

  17. Auditory Spatial Coding Flexibly Recruits Anterior, but Not Posterior, Visuotopic Parietal Cortex

    OpenAIRE

    Michalka, Samantha W.; Rosen, Maya L.; Kong, Lingqiang; Shinn-Cunningham, Barbara G.; Somers, David C.

    2015-01-01

    Audition and vision both convey spatial information about the environment, but much less is known about mechanisms of auditory spatial cognition than visual spatial cognition. Human cortex contains >20 visuospatial map representations but no reported auditory spatial maps. The intraparietal sulcus (IPS) contains several of these visuospatial maps, which support visuospatial attention and short-term memory (STM). Neuroimaging studies also demonstrate that parietal cortex is activated during au...

  18. Attentional effects of lesions to the anterior cingulate cortex: how prior reinforcement influences distractibility

    OpenAIRE

    Newman, Lori A.; McGaughy, Jill

    2011-01-01

    Morphological changes in the anterior cingulate cortex are found in subjects with schizophrenia, attention deficit hyperactivity disorder, and obsessive compulsive disorder. These changes are hypothesized to underlie the impairments these individuals show on tasks that require cognitive control. The anterior cingulate cortex has previously been shown to be active in situations involving high conflict, presentation of salient, distracting stimuli, and error processing, i.e. situations that occ...

  19. Human Development XI: The Structure of the Cerebral Cortex. Are There Really Modules in the Brain?

    OpenAIRE

    Tyge Dahl Hermansen; Søren Ventegodt; Isack Kandel

    2007-01-01

    The structure of human consciousness is thought to be closely connected to the structure of cerebral cortex. One of the most appreciated concepts in this regard is the Szanthagothei model of a modular building of neo-cortex. The modules are believed to organize brain activity pretty much like a computer. We looked at examples in the literature and argue that there is no significant evidence that supports Szanthagothei's model. We discuss the use of the limited genetic information, the cortico...

  20. Online learning and stimulus-driven responses of neurons in visual cortex

    OpenAIRE

    Tang, Huajin; Li, Haizhou; Yi, Zhang

    2010-01-01

    In understanding how visual scene is processed in visual cortex, it has been an intriguing problem for theoretical and experimental neuroscientists to examine the relationship between visual stimuli and the induced responses of visual cortex. In particular, it is less explored whether and how the collective responses of visual neurons are patterned to reflect the geometrical regularities. In this paper, through a computation model and statistical analysis, we show that the orientation prefere...

  1. Specificity of auditory-guided visual perceptual learning suggests crossmodal plasticity in early visual cortex

    OpenAIRE

    Beer, Anton L.; Watanabe, Takeo

    2009-01-01

    Sounds modulate visual perception. Blind humans show altered brain activity in early visual cortex. However, it is still unclear whether crossmodal activity in visual cortex results from unspecific top-down feedback, a lack of visual input, or genuinely reflects crossmodal interactions at early sensory levels. We examined how sounds affect visual perceptual learning in sighted adults. Visual motion discrimination was tested prior to and following eight sessions in which observers were exposed...

  2. Perceptual Learning Increases The Strength of The Earliest Signals in Visual Cortex

    OpenAIRE

    Bao, Min; Yang, Lin; Rios, Cristina; He, Bin; Engel, Stephen A.

    2010-01-01

    Training improves performance on most visual tasks. Such perceptual learning can modify how information is read out from, and represented in, later visual areas, but effects on early visual cortex are controversial. In particular, it remains unknown whether learning can reshape neural response properties in early visual areas independent from feedback arising in later cortical areas. Here, we tested whether learning can modify feed-forward signals in early visual cortex as measured by the hum...

  3. Eight open questions in the computational modeling of higher sensory cortex.

    Science.gov (United States)

    Yamins, Daniel Lk; DiCarlo, James J

    2016-04-01

    Propelled by advances in biologically inspired computer vision and artificial intelligence, the past five years have seen significant progress in using deep neural networks to model response patterns of neurons in visual cortex. In this paper, we briefly review this progress and then discuss eight key 'open questions' that we believe will drive research in computational models of sensory systems over the next five years, both in visual cortex and beyond. PMID:26921828

  4. Handedness Is Associated with Asymmetries in Gyrification of the Cerebral Cortex of Chimpanzees

    OpenAIRE

    Hopkins, William D.; Cantalupo, Claudio; Taglialatela, Jared

    2006-01-01

    Gyrification of the cerebral cortex reflects complexity in cortical folding during development of the brain. In this paper, we evaluated whether chimpanzees show asymmetries in gyrification and if variation in gyrification asymmetries were associated with handedness. Magnetic resonance images were obtained in a sample of 76 chimpanzees, and gyrification measures were obtained from 10 equally spaced slices of the cortex. Asymmetry quotients (AQs) in gyrification were compared for 4 measures of...

  5. Long-term modifications of synaptic efficacy in the human inferior and middle temporal cortex.

    OpenAIRE

    Chen, W R; Lee, S.; Kato, K.; Spencer, D D; Shepherd, G M; Williamson, A

    1996-01-01

    The primate temporal cortex has been demonstrated to play an important role in visual memory and pattern recognition. It is of particular interest to investigate whether activity-dependent modification of synaptic efficacy, a presumptive mechanism for learning and memory, is present in this cortical region. Here we address this issue by examining the induction of synaptic plasticity in surgically resected human inferior and middle temporal cortex. The results show that synaptic strength in th...

  6. A computational role for bistability and traveling waves in motor cortex

    OpenAIRE

    Heitmann, Stewart; Gong, Pulin; Breakspear, Michael

    2012-01-01

    Adaptive changes in behavior require rapid changes in brain states yet the brain must also remain stable. We investigated two neural mechanisms for evoking rapid transitions between spatiotemporal synchronization patterns of beta oscillations (13–30 Hz) in motor cortex. Cortex was modeled as a sheet of neural oscillators that were spatially coupled using a center-surround connection topology. Manipulating the inhibitory surround was found to evoke reliable transitions between synchronous osci...

  7. Generation of theta activity (RSA) in the cingulate cortex of the rat

    OpenAIRE

    Holsheimer, J.

    1982-01-01

    Unit activity recorded from the cingulate cortex during theta rhythm shows periodic trains of spikes which are phase-locked to the local theta field potential waves. These cortical theta units were also shown to be correlated with hippocampal theta units. These findings, along with the fact that theta field potentials show a phase reversal within the cingulate cortex, lead to the conclusion that this cortical area is a source of theta activity.

  8. The determination of projection neuron identity in the developing cerebral cortex

    OpenAIRE

    Leone, Dino P.; Srinivasan, Karpagam; Chen, Bin; Alcamo, Elizabeth; McConnell, Susan K.

    2008-01-01

    Here we review the mechanisms that determine projection neuron identity during cortical development. Pyramidal neurons in the mammalian cerebral cortex can be classified into two major classes: corticocortical projection neurons, which are concentrated in the upper layers of the cortex, and subcortical projection neurons, which are found in the deep layers. Early progenitor cells in the ventricular zone produce deep layer neurons that express transcription factors including Sox5, Fezf2, and C...

  9. A rate code for sound azimuth in monkey auditory cortex: implications for human neuroimaging studies

    OpenAIRE

    Werner-Reiss, Uri; Jennifer M Groh

    2008-01-01

    Is sound location represented in the auditory cortex of humans and monkeys? Human neuroimaging experiments have had only mixed success at demonstrating sound location sensitivity in primary auditory cortex. This is in apparent conflict with studies in monkeys and other animals, where single-unit recording studies have found stronger evidence for spatial sensitivity. Does this apparent discrepancy reflect a difference between humans and animals, or does it reflect differences in the sensitivit...

  10. ACETYLCHOLINE RELEASE IN THE HIPPOCAMPUS AND PRELIMBIC CORTEX DURING ACQUISITION OF A SOCIALLY TRANSMITTED FOOD PREFERENCE

    OpenAIRE

    Gold, P E; Countryman, R.A.; Dukala, D.; Chang, Q.

    2011-01-01

    Interference with cholinergic functions in hippocampus and prefrontal cortex impairs learning and memory for social transmission of food preference, suggesting that acetylcholine (ACh) release in the two brain regions may be important for acquiring the food preference. This experiment examined release of ACh in the hippocampus and prefrontal cortex of rats during training for social transmission of food preference. After demonstrator rats ate a food with novel flavor and odor, a social transm...

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

    Science.gov (United States)

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

    2016-04-01

    SEE KRINGELBACH AND RAPUANO DOI101093/BRAIN/AWW049 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE: The orbitofrontal cortex is known to carry information regarding expected reward, risk and experienced outcome. Yet, due to inherent limitations in lesion and neuroimaging methods, the neural dynamics of these computations has remained elusive in humans. Here, taking advantage of the high temporal definition of intracranial recordings, we characterize the neurophysiological signatures of the intact orbitofrontal cortex in processing information relevant for risky decisions. Local field potentials were recorded from the intact orbitofrontal cortex of patients suffering from drug-refractory partial epilepsy with implanted depth electrodes as they performed a probabilistic reward learning task that required them to associate visual cues with distinct reward probabilities. We observed three successive signals: (i) around 400 ms after cue presentation, the amplitudes of the local field potentials increased with reward probability; (ii) a risk signal emerged during the late phase of reward anticipation and during the outcome phase; and (iii) an experienced value signal appeared at the time of reward delivery. Both the medial and lateral orbitofrontal cortex encoded risk and reward probability while the lateral orbitofrontal cortex played a dominant role in coding experienced value. The present study provides the first evidence from intracranial recordings that the human orbitofrontal cortex codes reward risk both during late reward anticipation and during the outcome phase at a time scale of milliseconds. Our findings offer insights into the rapid mechanisms underlying the ability to learn structural relationships from the environment. PMID:26811252

  12. Alterations in neuronal morphology in infralimbic cortex predict resistance to fear extinction following acute stress.

    Science.gov (United States)

    Moench, Kelly M; Maroun, Mouna; Kavushansky, Alexandra; Wellman, Cara

    2016-06-01

    Dysfunction in corticolimbic circuits that mediate the extinction of learned fear responses is thought to underlie the perseveration of fear in stress-related psychopathologies, including post-traumatic stress disorder. Chronic stress produces dendritic hypertrophy in basolateral amygdala (BLA) and dendritic hypotrophy in medial prefrontal cortex, whereas acute stress leads to hypotrophy in both BLA and prelimbic cortex. Additionally, both chronic and acute stress impair extinction retrieval. Here, we examined the effects of a single elevated platform stress on extinction learning and dendritic morphology in infralimbic cortex, a region considered to be critical for extinction. Acute stress produced resistance to extinction, as well as dendritic retraction in infralimbic cortex. Spine density on apical and basilar terminal branches was unaffected by stress. However, animals that underwent conditioning and extinction had decreased spine density on apical terminal branches. Thus, whereas dendritic morphology in infralimbic cortex appears to be particularly sensitive to stress, changes in spines may more sensitively reflect learning. Further, in stressed rats that underwent conditioning and extinction, the level of extinction learning was correlated with spine densities, in that rats with poorer extinction retrieval had more immature spines and fewer thin spines than rats with better extinction retrieval, suggesting that stress may have impaired learning-related spine plasticity. These results may have implications for understanding the role of medial prefrontal cortex in learning deficits associated with stress-related pathologies. PMID:26844245

  13. Functional asymmetry of left and right avian piriform cortex in homing pigeons' navigation.

    Science.gov (United States)

    Gagliardo, Anna; Odetti, Francesca; Ioalè, Paolo; Pecchia, Tommaso; Vallortigara, Giorgio

    2005-07-01

    It has been shown that homing pigeons rely on olfactory cues to navigate over unfamiliar areas and that any kind of olfactory impairment produces a dramatic reduction of navigational performance from unfamiliar sites. The avian piriform cortex is the main projection field of olfactory bulbs and it is supposed to process olfactory information; not surprisingly bilateral lesions to this telencephalic region disrupt homing pigeon navigation. In the present study, we attempted to assess whether the left and right piriform cortex are differentially involved in the use of the olfactory navigational map. Therefore, we released from unfamiliar locations pigeons subjected, when adult, to unilateral ablation of the piriform cortex. After being released, the pigeons lesioned to the right piriform cortex orientated similarly to the intact controls. On the contrary, the left lesioned birds were significantly more scattered than controls, showing a crucial role of the left piriform cortex in processing the olfactory cues needed for determining the direction of displacement. However, both lesioned groups were significantly slower than controls in flying back to the home loft, showing that the integrity of both sides of the piriform cortex is necessary to accomplish the whole homing process. PMID:16029208

  14. Motor, cognitive, and affective areas of the cerebral cortex influence the adrenal medulla.

    Science.gov (United States)

    Dum, Richard P; Levinthal, David J; Strick, Peter L

    2016-08-30

    Modern medicine has generally viewed the concept of "psychosomatic" disease with suspicion. This view arose partly because no neural networks were known for the mind, conceptually associated with the cerebral cortex, to influence autonomic and endocrine systems that control internal organs. Here, we used transneuronal transport of rabies virus to identify the areas of the primate cerebral cortex that communicate through multisynaptic connections with a major sympathetic effector, the adrenal medulla. We demonstrate that two broad networks in the cerebral cortex have access to the adrenal medulla. The larger network includes all of the cortical motor areas in the frontal lobe and portions of somatosensory cortex. A major component of this network originates from the supplementary motor area and the cingulate motor areas on the medial wall of the hemisphere. These cortical areas are involved in all aspects of skeletomotor control from response selection to motor preparation and movement execution. The second, smaller network originates in regions of medial prefrontal cortex, including a major contribution from pregenual and subgenual regions of anterior cingulate cortex. These cortical areas are involved in higher-order aspects of cognition and affect. These results indicate that specific multisynaptic circuits exist to link movement, cognition, and affect to the function of the adrenal medulla. This circuitry may mediate the effects of internal states like chronic stress and depression on organ function and, thus, provide a concrete neural substrate for some psychosomatic illness. PMID:27528671

  15. Developmental changes in mental arithmetic: evidence for increased functional specialization in the left inferior parietal cortex.

    Science.gov (United States)

    Rivera, S M; Reiss, A L; Eckert, M A; Menon, V

    2005-11-01

    Arithmetic reasoning is arguably one of the most important cognitive skills a child must master. Here we examine neurodevelopmental changes in mental arithmetic. Subjects (ages 8-19 years) viewed arithmetic equations and were asked to judge whether the results were correct or incorrect. During two-operand addition or subtraction trials, for which accuracy was comparable across age, older subjects showed greater activation in the left parietal cortex, along the supramarginal gyrus and adjoining anterior intra-parietal sulcus as well as the left lateral occipital temporal cortex. These age-related changes were not associated with alterations in gray matter density, and provide novel evidence for increased functional maturation with age. By contrast, younger subjects showed greater activation in the prefrontal cortex, including the dorsolateral and ventrolateral prefrontal cortex and the anterior cingulate cortex, suggesting that they require comparatively more working memory and attentional resources to achieve similar levels of mental arithmetic performance. Younger subjects also showed greater activation of the hippocampus and dorsal basal ganglia, reflecting the greater demands placed on both declarative and procedural memory systems. Our findings provide evidence for a process of increased functional specialization of the left inferior parietal cortex in mental arithmetic, a process that is accompanied by decreased dependence on memory and attentional resources with development. PMID:15716474

  16. Internal transcribed spacer 2 barcode: A good tool for identifying Acanthopanacis cortex

    Directory of Open Access Journals (Sweden)

    Sha eZhao

    2015-10-01

    Full Text Available Acanthopanacis cortex has been used in clinical applications for a long time. Considering some historical and geographical factors, Acanthopanacis cortex is easily confused with other herbs in medicine markets, thereby causing potential safety issues. In this study, we used the internal transcribed spacer 2 (ITS2 barcode to identify 69 samples belonging to six species, including Acanthopanacis cortex and its adulterants. The nearest distance, single-nucleotide polymorphisms (SNPs, and neighbor-joining (NJ tree methods were used to evaluate the identification ability of the ITS2 barcode. According to the kimura-2-parameter model, the intraspecific distance of Eleutherococcus nodiflorus ITS2 sequences ranged from 0 to 0.0132. The minimum interspecific distance between E. nodiflorus and E. giraldii was 0.0221, which was larger than the maximum intraspecific distance of E. nodiflorus. Three stable SNPs in ITS2 can be used to distinguish Acanthopanacis cortex and its closely related species. The NJ tree indicated that the Acanthopanacis cortex samples clustered into one clade, which can be distinguished clearly from the adulterants of this herb. A secondary structure of ITS2 provided another dimensionality to identify species. In conclusion, the ITS2 barcode effectively identifies Acanthopanacis cortex, and DNA barcoding is a convenient tool for medicine market supervision.

  17. Effects of Physical Exercise on Working Memory and Prefrontal Cortex Function in Post-Stroke Patients.

    Science.gov (United States)

    Moriya, M; Aoki, C; Sakatani, K

    2016-01-01

    Physical exercise enhances prefrontal cortex activity and improves working memory performance in healthy older adults, but it is not clear whether this remains the case in post-stroke patients. Therefore, the aim of this study was to examine the acute effect of physical exercise on prefrontal cortex activity in post-stroke patients using near-infrared spectroscopy (NIRS). We studied 11 post-stroke patients. The patients performed Sternberg-type working memory tasks before and after moderate intensity aerobic exercise (40 % of maximal oxygen uptake) with a cycling ergometer for 15 min. We measured the NIRS response at the prefrontal cortex during the working memory task. We evaluated behavioral performance (response time and accuracy) of the working memory task. It was found that physical exercise improved behavioral performance of the working memory task compared with the control condition (p physical exercise enhanced prefrontal cortex activation, particularly in the right prefrontal cortex (p exercise enhances prefrontal cortex activity and improves working memory performance in post-stroke patients. PMID:27526144

  18. Single-cell correlates of a representational boundary in rat somatosensory cortex.

    Science.gov (United States)

    Hickmott, P W; Merzenich, M M

    1998-06-01

    In primary somatosensory cortex (S1), the transition from one representation to the next is typically abrupt when assayed physiologically. However, the extent of anatomical projections to and within the cortex do not strictly respect these physiologically defined transitions. Physiological properties, such as synaptic strengths or intracortical inhibition, have been hypothesized to account for the functionally defined precision of these representational borders. Because these representational borders can be translocated across the cortex by manipulations or behaviors that change the activity patterns of inputs to the cortex, understanding the physiological mechanisms that delimit representations is also an important starting point for understanding cortical plasticity. A novel in vivo and in vitro preparation has been developed to examine the cellular and synaptic mechanisms that underlie representational borders in the rat. In vivo, a short segment of the border between the forepaw-lower jaw representations in rat S1 was mapped using standard electrophysiological methods and was visibly marked using iontophoresis of pontamine sky blue dye. Slices were then obtained from this marked region and maintained in vitro. Intracellularly recorded responses to electrical stimulation of supragranular cortex were obtained from single neurons near the border in response to stimulation within the representational zone or across the border. Both excitatory and inhibitory responses were smaller when evoked by stimuli that activated projections that crossed borders, as compared with stimuli to projections that did not. These findings indicate that intracortical network properties are contributing to the expressions of representational discontinuities in the cortex. PMID:9592117

  19. What Does the Anatomical Organization of the Entorhinal Cortex Tell Us?

    Directory of Open Access Journals (Sweden)

    Cathrin B. Canto

    2008-01-01

    Full Text Available The entorhinal cortex is commonly perceived as a major input and output structure of the hippocampal formation, entertaining the role of the nodal point of cortico-hippocampal circuits. Superficial layers receive convergent cortical information, which is relayed to structures in the hippocampus, and hippocampal output reaches deep layers of entorhinal cortex, that project back to the cortex. The finding of the grid cells in all layers and reports on interactions between deep and superficial layers indicate that this rather simplistic perception may be at fault. Therefore, an integrative approach on the entorhinal cortex, that takes into account recent additions to our knowledge database on entorhinal connectivity, is timely. We argue that layers in entorhinal cortex show different functional characteristics most likely not on the basis of strikingly different inputs or outputs, but much more likely on the basis of differences in intrinsic organization, combined with very specific sets of inputs. Here, we aim to summarize recent anatomical data supporting the notion that the traditional description of the entorhinal cortex as a layered input-output structure for the hippocampal formation does not give the deserved credit to what this structure might be contributing to the overall functions of cortico-hippocampal networks.

  20. Perirhinal cortex lesions in rats: Novelty detection and sensitivity to interference.

    Science.gov (United States)

    Albasser, Mathieu M; Olarte-Sánchez, Cristian M; Amin, Eman; Brown, Malcolm W; Kinnavane, Lisa; Aggleton, John P

    2015-06-01

    Rats with perirhinal cortex lesions received multiple object recognition trials within a continuous session to examine whether they show false memories. Experiment 1 focused on exploration patterns during the first object recognition test postsurgery, in which each trial contained 1 novel and 1 familiar object. The perirhinal cortex lesions reduced time spent exploring novel objects, but did not affect overall time spent exploring the test objects (novel plus familiar). Replications with subsequent cohorts of rats (Experiments 2, 3, 4.1) repeated this pattern of results. When all recognition memory data were combined (Experiments 1-4), giving totals of 44 perirhinal lesion rats and 40 surgical sham controls, the perirhinal cortex lesions caused a marginal reduction in total exploration time. That decrease in time with novel objects was often compensated by increased exploration of familiar objects. Experiment 4 also assessed the impact of proactive interference on recognition memory. Evidence emerged that prior object experience could additionally impair recognition performance in rats with perirhinal cortex lesions. Experiment 5 examined exploration levels when rats were just given pairs of novel objects to explore. Despite their perirhinal cortex lesions, exploration levels were comparable with those of control rats. While the results of Experiment 4 support the notion that perirhinal lesions can increase sensitivity to proactive interference, the overall findings question whether rats lacking a perirhinal cortex typically behave as if novel objects are familiar, that is, show false recognition. Rather, the rats retain a signal of novelty but struggle to discriminate the identity of that signal. PMID:26030425

  1. Does the Entorhinal Cortex use the Fourier Transform?

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    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.

  2. Disconnection Between Amygdala and Medial Prefrontal Cortex in Psychotic Disorders.

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    Mukherjee, Prerona; Sabharwal, Amri; Kotov, Roman; Szekely, Akos; Parsey, Ramin; Barch, Deanna M; Mohanty, Aprajita

    2016-07-01

    Distracting emotional information impairs attention more in schizophrenia (SCZ) than in never-psychotic individuals. However, it is unclear whether this impairment and its neural circuitry is indicative generally of psychosis, or specifically of SCZ, and whether it is even more specific to certain SCZ symptoms (eg, deficit syndrome). It is also unclear if this abnormality contributes to impaired behavioral performance and real-world functioning. Functional imaging data were recorded while individuals with SCZ, bipolar disorder with psychosis (BDP) and no history of psychotic disorders (CON) attended to identity of faces while ignoring their emotional expressions. We examined group differences in functional connectivity between amygdala, involved in emotional evaluation, and sub-regions of medial prefrontal cortex (MPFC), involved in emotion regulation and cognitive control. Additionally, we examined correlation of this connectivity with deficit syndrome and real-world functioning. Behaviorally, SCZ showed the worst accuracy when matching the identity of emotional vs neutral faces. Neurally, SCZ showed lower amygdala-MPFC connectivity than BDP and CON. BPD did not differ from CON, neurally or behaviorally. In patients, reduced amygdala-MPFC connectivity during emotional distractors was related to worse emotional vs neutral accuracy, greater deficit syndrome severity, and unemployment. Thus, reduced amygdala-MPFC functional connectivity during emotional distractors reflects a deficit that is specific to SCZ. This reduction in connectivity is associated with worse clinical and real-world functioning. Overall, these findings provide support for the specificity and clinical utility of amygdala-MPFC functional connectivity as a potential neural marker of SCZ. PMID:26908926

  3. Proteomic analysis of rat cerebral cortex following subchronic acrolein toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Rashedinia, Marzieh; Lari, Parisa [Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad (Iran, Islamic Republic of); Abnous, Khalil, E-mail: Abnouskh@mums.ac.r [Pharmaceutical Research Center, Department of Medicinal Chemistry, Mashhad University of Medical Sciences, Mashhad (Iran, Islamic Republic of); Hosseinzadeh, Hossein, E-mail: Hosseinzadehh@mums.ac.ir [Pharmaceutical Research Center, Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad (Iran, Islamic Republic of)

    2013-10-01

    Acrolein, a member of reactive α,β-unsaturated aldehydes, is a major environmental pollutant. Acrolein is also produced endogenously as a toxic by-product of lipid peroxidation. Because of high reactivity, acrolein may mediate oxidative damages to cells and tissues. It has been shown to be involved in a wide variety of pathological states including pulmonary, atherosclerosis and neurodegenerative diseases. In this study we employed proteomics approach to investigate the effects of subchronic oral exposures to 3 mg/kg of acrolein on protein expression profile in the brain of rats. Moreover effects of acrolein on malondialdehyde (MDA) levels and reduced glutathione (GSH) content were investigated. Our results revealed that treatment with acrolein changed levels of several proteins in diverse physiological process including energy metabolism, cell communication and transport, response to stimulus and metabolic process. Interestingly, several differentially over-expressed proteins, including β-synuclein, enolase and calcineurin, are known to be associated with human neurodegenerative diseases. Changes in the levels of some proteins were confirmed by Western blot. Moreover, acrolein increases the level of MDA, as a lipid peroxidation biomarker and decreased GSH concentrations, as a non-enzyme antioxidant in the brain of acrolein treated rats. These findings suggested that acrolein induces the oxidative stress and lipid peroxidation in the brain, and so that may contribute to the pathophysiology of neurological disorders. - Highlights: • Acrolein intoxication increased lipid peroxidation and deplete GSH in rat brain. • Effect of acrolein on protein levels of cerebral cortex was analyzed by 2DE-PAGE. • Levels of a number of proteins with different biological functions were increased.

  4. Multi-sensory integration in brainstem and auditory cortex.

    Science.gov (United States)

    Basura, Gregory J; Koehler, Seth D; Shore, Susan E

    2012-11-16

    Tinnitus is the perception of sound in the absence of a physical sound stimulus. It is thought to arise from aberrant neural activity within central auditory pathways that may be influenced by multiple brain centers, including the somatosensory system. Auditory-somatosensory (bimodal) integration occurs in the dorsal cochlear nucleus (DCN), where electrical activation of somatosensory regions alters pyramidal cell spike timing and rates of sound stimuli. Moreover, in conditions of tinnitus, bimodal integration in DCN is enhanced, producing greater spontaneous and sound-driven neural activity, which are neural correlates of tinnitus. In primary auditory cortex (A1), a similar auditory-somatosensory integration has been described in the normal system (Lakatos et al., 2007), where sub-threshold multisensory modulation may be a direct reflection of subcortical multisensory responses (Tyll et al., 2011). The present work utilized simultaneous recordings from both DCN and A1 to directly compare bimodal integration across these separate brain stations of the intact auditory pathway. Four-shank, 32-channel electrodes were placed in DCN and A1 to simultaneously record tone-evoked unit activity in the presence and absence of spinal trigeminal nucleus (Sp5) electrical activation. Bimodal stimulation led to long-lasting facilitation or suppression of single and multi-unit responses to subsequent sound in both DCN and A1. Immediate (bimodal response) and long-lasting (bimodal plasticity) effects of Sp5-tone stimulation were facilitation or suppression of tone-evoked firing rates in DCN and A1 at all Sp5-tone pairing intervals (10, 20, and 40 ms), and greater suppression at 20 ms pairing-intervals for single unit responses. Understanding the complex relationships between DCN and A1 bimodal processing in the normal animal provides the basis for studying its disruption in hearing loss and tinnitus models. This article is part of a Special Issue entitled: Tinnitus Neuroscience

  5. Auditory short-term memory in the primate auditory cortex.

    Science.gov (United States)

    Scott, Brian H; Mishkin, Mortimer

    2016-06-01

    Sounds are fleeting, and assembling the sequence of inputs at the ear into a coherent percept requires auditory memory across various time scales. Auditory short-term memory comprises at least two components: an active ׳working memory' bolstered by rehearsal, and a sensory trace that may be passively retained. Working memory relies on representations recalled from long-term memory, and their rehearsal may require phonological mechanisms unique to humans. The sensory component, passive short-term memory (pSTM), is tractable to study in nonhuman primates, whose brain architecture and behavioral repertoire are comparable to our own. This review discusses recent advances in the behavioral and neurophysiological study of auditory memory with a focus on single-unit recordings from macaque monkeys performing delayed-match-to-sample (DMS) tasks. Monkeys appear to employ pSTM to solve these tasks, as evidenced by the impact of interfering stimuli on memory performance. In several regards, pSTM in monkeys resembles pitch memory in humans, and may engage similar neural mechanisms. Neural correlates of DMS performance have been observed throughout the auditory and prefrontal cortex, defining a network of areas supporting auditory STM with parallels to that supporting visual STM. These correlates include persistent neural firing, or a suppression of firing, during the delay period of the memory task, as well as suppression or (less commonly) enhancement of sensory responses when a sound is repeated as a ׳match' stimulus. Auditory STM is supported by a distributed temporo-frontal network in which sensitivity to stimulus history is an intrinsic feature of auditory processing. This article is part of a Special Issue entitled SI: Auditory working memory. PMID:26541581

  6. Heterogeneous and nonlinear development of human posterior parietal cortex function.

    Science.gov (United States)

    Chang, Ting-Ting; Metcalfe, Arron W S; Padmanabhan, Aarthi; Chen, Tianwen; Menon, Vinod

    2016-02-01

    Human cognitive problem solving skills undergo complex experience-dependent changes from childhood to adulthood, yet most neurodevelopmental research has focused on linear changes with age. Here we challenge this limited view, and investigate spatially heterogeneous and nonlinear neurodevelopmental profiles between childhood, adolescence, and young adulthood, focusing on three cytoarchitectonically distinct posterior parietal cortex (PPC) regions implicated in numerical problem solving: intraparietal sulcus (IPS), angular gyrus (AG), and supramarginal gyrus (SMG). Adolescents demonstrated better behavioral performance relative to children, but their performance was equivalent to that of adults. However, all three groups differed significantly in their profile of activation and connectivity across the PPC subdivisions. Activation in bilateral ventral IPS subdivision IPS-hIP1, along with adjoining anterior AG subdivision, AG-PGa, and the posterior SMG subdivision, SMG-PFm, increased linearly with age, whereas the posterior AG subdivision, AG-PGp, was equally deactivated in all three groups. In contrast, the left anterior SMG subdivision, SMG-PF, showed an inverted U-shaped profile across age groups such that adolescents exhibited greater activation than both children and young adults. Critically, greater SMG-PF activation was correlated with task performance only in adolescents. Furthermore, adolescents showed greater task-related functional connectivity of the SMG-PF with ventro-temporal, anterior temporal and prefrontal cortices, relative to both children and adults. These results suggest that nonlinear up-regulation of SMG-PF and its interconnected functional circuits facilitate adult-level performance in adolescents. Our study provides novel insights into heterogeneous age-related maturation of the PPC underlying cognitive skill acquisition, and further demonstrates how anatomically precise analysis of both linear and nonlinear neurofunctional changes with age is

  7. Oculomotor Remapping of Visual Information to Foveal Retinotopic Cortex.

    Science.gov (United States)

    Knapen, Tomas; Swisher, Jascha D; Tong, Frank; Cavanagh, Patrick

    2016-01-01

    Our eyes continually jump around the visual scene to bring the high-resolution, central part of our vision onto objects of interest. We are oblivious to these abrupt shifts, perceiving the visual world to appear reassuringly stable. A process called remapping has been proposed to mediate this perceptual stability for attended objects by shifting their retinotopic representation to compensate for the effects of the upcoming eye movement. In everyday vision, observers make goal-directed eye movements towards items of interest bringing them to the fovea and, for these items, the remapped activity should impinge on foveal regions of the retinotopic maps in visual cortex. Previous research has focused instead on remapping for targets that were not saccade goals, where activity is remapped to a new peripheral location rather than to the foveal representation. We used functional magnetic resonance imaging (fMRI) and a phase-encoding design to investigate remapping of spatial patterns of activity towards the fovea/parafovea for saccade targets that were removed prior to completion of the eye movement. We found strong evidence of foveal remapping in retinotopic visual areas, which failed to occur when observers merely attended to the same peripheral target without making eye movements towards it. Significantly, the spatial profile of the remapped response matched the orientation and size of the saccade target, and was appropriately scaled to reflect the retinal extent of the stimulus had it been foveated. We conclude that this remapping of spatially structured information to the fovea may serve as an important mechanism to support our world-centered sense of location across goal-directed eye movements under natural viewing conditions. PMID:27445715

  8. Prognostic value of posteromedial cortex deactivation in mild cognitive impairment.

    Directory of Open Access Journals (Sweden)

    Jeffrey R Petrella

    Full Text Available BACKGROUND: Normal subjects deactivate specific brain regions, notably the posteromedial cortex (PMC, during many tasks. Recent cross-sectional functional magnetic resonance imaging (fMRI data suggests that deactivation during memory tasks is impaired in Alzheimer's disease (AD. The goal of this study was to prospectively determine the prognostic significance of PMC deactivation in mild cognitive impairment (MCI. METHODOLOGY/PRINCIPAL FINDINGS: 75 subjects (34 MCI, 13 AD subjects and 28 controls underwent baseline fMRI scanning during encoding of novel and familiar face-name pairs. MCI subjects were followed longitudinally to determine conversion to AD. Regression and analysis of covariance models were used to assess the effect of PMC activation/deactivation on conversion to dementia as well as in the longitudinal change in dementia measures. At longitudinal follow up of up to 3.5 years (mean 2.5+/-0.79 years, 11 MCI subjects converted to AD. The proportion of deactivators was significantly different across all groups: controls (79%, MCI-Nonconverters (73%, MCI-converters (45%, and AD (23% (p<0.05. Mean PMC activation magnitude parameter estimates, at baseline, were negative in the control (-0.57+/-0.12 and MCI-Nonconverter (-0.33+/-0.14 groups, and positive in the MCI-Converter (0.37+/-0.40 and AD (0.92+/-0.30 groups. The effect of diagnosis on PMC deactivation remained significant after adjusting for age, education and baseline Mini-Mental State Exam (p<0.05. Baseline PMC activation magnitude was correlated with change in dementia ratings from baseline. CONCLUSION: Loss of physiological functional deactivation in the PMC may have prognostic value in preclinical AD, and could aid in profiling subgroups of MCI subjects at greatest risk for progressive cognitive decline.

  9. Fluctuation scaling in the visual cortex at threshold

    Science.gov (United States)

    Medina, José M.; Díaz, José A.

    2016-05-01

    Fluctuation scaling relates trial-to-trial variability to the average response by a power function in many physical processes. Here we address whether fluctuation scaling holds in sensory psychophysics and its functional role in visual processing. We report experimental evidence of fluctuation scaling in human color vision and form perception at threshold. Subjects detected thresholds in a psychophysical masking experiment that is considered a standard reference for studying suppression between neurons in the visual cortex. For all subjects, the analysis of threshold variability that results from the masking task indicates that fluctuation scaling is a global property that modulates detection thresholds with a scaling exponent that departs from 2, β =2.48 ±0.07 . We also examine a generalized version of fluctuation scaling between the sample kurtosis K and the sample skewness S of threshold distributions. We find that K and S are related and follow a unique quadratic form K =(1.19 ±0.04 ) S2+(2.68 ±0.06 ) that departs from the expected 4/3 power function regime. A random multiplicative process with weak additive noise is proposed based on a Langevin-type equation. The multiplicative process provides a unifying description of fluctuation scaling and the quadratic S -K relation and is related to on-off intermittency in sensory perception. Our findings provide an insight into how the human visual system interacts with the external environment. The theoretical methods open perspectives for investigating fluctuation scaling and intermittency effects in a wide variety of natural, economic, and cognitive phenomena.

  10. Medial prefrontal cortex stimulation modulates the processing of conditioned fear

    Directory of Open Access Journals (Sweden)

    Anne Guhn

    2014-02-01

    Full Text Available The extinction of conditioned fear is dependent on an efficient interplay between the amygdala and the medial prefrontal cortex (mPFC. In rats, high-frequency electrical mPFC stimulation was shown to improve extinction by a reduction of amygdala activity. However, so far it is unclear whether stimulation of homologues regions in humans might have similar beneficial effects.Healthy volunteers received one-session of either active or sham repetitive transcranial magnetic stimulation (rTMS covering the mPFC while undergoing a two-day fear conditioning and extinction paradigm. rTMS was applied offline after fear acquisition in which one of two faces (CS+ but not CS- was associated with an aversive scream (UCS. Immediate extinction learning (day 1 and extinction recall (day 2 were conducted without UCS delivery. Conditioned responses were assessed in a multimodal approach using fear-potentiated startle (FPS, skin conductance responses (SCR, functional near-infrared spectroscopy (fNIRS and self-report scales. Consistent with the hypothesis of a modulated processing of conditioned fear after high-frequency rTMS, the active group showed a reduced CS+/CS- discrimination during extinction learning as evident in FPS as well as in SCR and arousal ratings. FPS responses to CS+ further showed a linear decrement throughout both extinction sessions. This study describes the first experimental approach of influencing conditioned fear by using rTMS which can be a basis for future studies investigating a complementation of mPFC stimulation to cognitive behavioral therapy.

  11. Proteomic analysis of rat cerebral cortex following subchronic acrolein toxicity

    International Nuclear Information System (INIS)

    Acrolein, a member of reactive α,β-unsaturated aldehydes, is a major environmental pollutant. Acrolein is also produced endogenously as a toxic by-product of lipid peroxidation. Because of high reactivity, acrolein may mediate oxidative damages to cells and tissues. It has been shown to be involved in a wide variety of pathological states including pulmonary, atherosclerosis and neurodegenerative diseases. In this study we employed proteomics approach to investigate the effects of subchronic oral exposures to 3 mg/kg of acrolein on protein expression profile in the brain of rats. Moreover effects of acrolein on malondialdehyde (MDA) levels and reduced glutathione (GSH) content were investigated. Our results revealed that treatment with acrolein changed levels of several proteins in diverse physiological process including energy metabolism, cell communication and transport, response to stimulus and metabolic process. Interestingly, several differentially over-expressed proteins, including β-synuclein, enolase and calcineurin, are known to be associated with human neurodegenerative diseases. Changes in the levels of some proteins were confirmed by Western blot. Moreover, acrolein increases the level of MDA, as a lipid peroxidation biomarker and decreased GSH concentrations, as a non-enzyme antioxidant in the brain of acrolein treated rats. These findings suggested that acrolein induces the oxidative stress and lipid peroxidation in the brain, and so that may contribute to the pathophysiology of neurological disorders. - Highlights: • Acrolein intoxication increased lipid peroxidation and deplete GSH in rat brain. • Effect of acrolein on protein levels of cerebral cortex was analyzed by 2DE-PAGE. • Levels of a number of proteins with different biological functions were increased

  12. Reservoir Computing Properties of Neural Dynamics in Prefrontal Cortex

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    Procyk, Emmanuel; Dominey, Peter Ford

    2016-01-01

    Primates display a remarkable ability to adapt to novel situations. Determining what is most pertinent in these situations is not always possible based only on the current sensory inputs, and often also depends on recent inputs and behavioral outputs that contribute to internal states. Thus, one can ask how cortical dynamics generate representations of these complex situations. It has been observed that mixed selectivity in cortical neurons contributes to represent diverse situations defined by a combination of the current stimuli, and that mixed selectivity is readily obtained in randomly connected recurrent networks. In this context, these reservoir networks reproduce the highly recurrent nature of local cortical connectivity. Recombining present and past inputs, random recurrent networks from the reservoir computing framework generate mixed selectivity which provides pre-coded representations of an essentially universal set of contexts. These representations can then be selectively amplified through learning to solve the task at hand. We thus explored their representational power and dynamical properties after training a reservoir to perform a complex cognitive task initially developed for monkeys. The reservoir model inherently displayed a dynamic form of mixed selectivity, key to the representation of the behavioral context over time. The pre-coded representation of context was amplified by training a feedback neuron to explicitly represent this context, thereby reproducing the effect of learning and allowing the model to perform more robustly. This second version of the model demonstrates how a hybrid dynamical regime combining spatio-temporal processing of reservoirs, and input driven attracting dynamics generated by the feedback neuron, can be used to solve a complex cognitive task. We compared reservoir activity to neural activity of dorsal anterior cingulate cortex of monkeys which revealed similar network dynamics. We argue that reservoir computing is a

  13. Apoptosis in the cortex of the developing mouse kidney.

    Science.gov (United States)

    Foley, Jonathan G D; Bard, Jonathan B L

    2002-12-01

    Published levels of apoptosis in developing rat kidney (approximately 2.5%) seem large for a tissue with no obvious need for continual cell death. This paper examines the levels and patterns of apoptosis and mitosis in the cortical region of the developing metanephros of the mouse, the standard mammalian model embryo. Using confocal microscopy on specimens stained with propidium iodide to highlight nuclear morphology, optical sections of wholemount kidneys to a depth of approximately 50 microm were analysed and mitotic, apoptotic and interphase nuclei counted in the various compartments. Of the approximately 200 000 cells examined over E11.5-16.5, 2-3% were mitotic, confirming observations based on cryosections; the mitotic index peaked at E14.5, dropping to approximately 0.5% by P14. The mean apoptotic index during this period was 0.28%; this figure from wholemounts was approximately 10% of that earlier reported in cryosectioned rat kidneys. One possible explanation for the difference is that cryosectioning turns out to create small nuclear fragments that can stain strongly with propidium. Such fragments are not seen in wholemounts and do not stain with TUNEL. Wholemount mouse E11.5 tails and E16.5 lungs were also analysed and both their mitotic and their apoptotic indexes were similar to those in wholemount developing kidneys. These results show that the level of apoptosis in wholemount embryonic mouse kidney cortex is far less than previously reported in cryosectioned rat embryonic kidneys, and typical of that in other mouse embryonic tissues whose development seems not to require apoptosis. PMID:12489759

  14. Cross-Modal Functional Reorganization of Visual and Auditory Cortex in Adult Cochlear Implant Users Identified with fNIRS

    Directory of Open Access Journals (Sweden)

    Ling-Chia Chen

    2016-01-01

    Full Text Available Cochlear implant (CI users show higher auditory-evoked activations in visual cortex and higher visual-evoked activation in auditory cortex compared to normal hearing (NH controls, reflecting functional reorganization of both visual and auditory modalities. Visual-evoked activation in auditory cortex is a maladaptive functional reorganization whereas auditory-evoked activation in visual cortex is beneficial for speech recognition in CI users. We investigated their joint influence on CI users’ speech recognition, by testing 20 postlingually deafened CI users and 20 NH controls with functional near-infrared spectroscopy (fNIRS. Optodes were placed over occipital and temporal areas to measure visual and auditory responses when presenting visual checkerboard and auditory word stimuli. Higher cross-modal activations were confirmed in both auditory and visual cortex for CI users compared to NH controls, demonstrating that functional reorganization of both auditory and visual cortex can be identified with fNIRS. Additionally, the combined reorganization of auditory and visual cortex was found to be associated with speech recognition performance. Speech performance was good as long as the beneficial auditory-evoked activation in visual cortex was higher than the visual-evoked activation in the auditory cortex. These results indicate the importance of considering cross-modal activations in both visual and auditory cortex for potential clinical outcome estimation.

  15. The medial prefrontal cortex-lateral entorhinal cortex circuit is essential for episodic-like memory and associative object-recognition.

    Science.gov (United States)

    Chao, Owen Y; Huston, Joseph P; Li, Jay-Shake; Wang, An-Li; de Souza Silva, Maria A

    2016-05-01

    The prefrontal cortex directly projects to the lateral entorhinal cortex (LEC), an important substrate for engaging item-associated information and relaying the information to the hippocampus. Here we ask to what extent the communication between the prefrontal cortex and LEC is critically involved in the processing of episodic-like memory. We applied a disconnection procedure to test whether the interaction between the medial prefrontal cortex (mPFC) and LEC is essential for the expression of recognition memory. It was found that male rats that received unilateral NMDA lesions of the mPFC and LEC in the same hemisphere, exhibited intact episodic-like (what-where-when) and object-recognition memories. When these lesions were placed in the opposite hemispheres (disconnection), episodic-like and associative memories for object identity, location and context were impaired. However, the disconnection did not impair the components of episodic memory, namely memory for novel object (what), object place (where) and temporal order (when), per se. Thus, the present findings suggest that the mPFC and LEC are a critical part of a neural circuit that underlies episodic-like and associative object-recognition memory. © 2015 Wiley Periodicals, Inc. PMID:26501829

  16. Crossmodal Association of Visual and Haptic Material Properties of Objects in the Monkey Ventral Visual Cortex.

    Science.gov (United States)

    Goda, Naokazu; Yokoi, Isao; Tachibana, Atsumichi; Minamimoto, Takafumi; Komatsu, Hidehiko

    2016-04-01

    Just by looking at an object, we can recognize its non-visual properties, such as hardness. The visual recognition of non-visual object properties is generally accurate [1], and influences actions toward the object [2]. Recent studies suggest that, in the primate brain, this may involve the ventral visual cortex, which represents objects in a way that reflects not only visual but also non-visual object properties, such as haptic roughness, hardness, and weight [3-7]. This new insight raises a fundamental question: how does the visual cortex come to represent non-visual properties--knowledge that cannot be acquired directly through vision? Here we addressed this unresolved question using fMRI in macaque monkeys. Specifically, we explored whether and how simple visuo-haptic experience--just seeing and touching objects made of various materials--can shape representational content in the visual cortex. We measured brain activity evoked by viewing images of objects before and after the monkeys acquired the visuo-haptic experience and decoded the representational space from the activity patterns [8]. We show that simple long-term visuo-haptic experience greatly impacts representation in the posterior inferior temporal cortex, the higher ventral visual cortex. After the experience, but not before, the activity pattern in this region well reflected the haptic material properties of the experienced objects. Our results suggest that neural representation of non-visual object properties in the visual cortex emerges through long-term crossmodal exposure to objects. This highlights the importance of unsupervised learning of crossmodal associations through everyday experience [9-12] for shaping representation in the visual cortex. PMID:26996504

  17. 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.

  18. Topographic organization of the basal forebrain projections to the perirhinal, postrhinal, and entorhinal cortex in rats.

    Science.gov (United States)

    Kondo, Hideki; Zaborszky, Laszlo

    2016-08-15

    Previous studies have shown that the basal forebrain (BF) modulates cortical activation via its projections to the entire cortical mantle. However, the organization of these projections is only partially understood or, for certain areas, unknown. In this study, we examined the topographic organization of cholinergic and noncholinergic projections from the BF to the perirhinal, postrhinal, and entorhinal cortex by using retrograde tracing combined with choline acetyltransferase (ChAT) immunohistochemistry in rats. The perirhinal and postrhinal cortex receives major cholinergic and noncholinergic input from the caudal BF, including the caudal globus pallidus and substantia innominata and moderate input from the horizontal limb of the diagonal band, whereas the entorhinal cortex receives major input from the rostral BF, including the medial septum and the vertical and horizontal limbs of the diagonal band. In the perirhinal cases, cholinergic projection neurons are distributed more caudally in the caudal globus pallidus than noncholinergic projection neurons. Compared with the perirhinal cases, the distribution of cholinergic and noncholinergic neurons projecting to the postrhinal cortex shifts slightly caudally in the caudal globus pallidus. The distribution of cholinergic and noncholinergic neurons projecting to the lateral entorhinal cortex extends more caudally in the BF than to the medial entorhinal cortex. The ratio of ChAT-positive projection neurons to total projection neurons is higher in the perirhinal/postrhinal cases (26-48%) than in the entorhinal cases (13-30%). These results indicate that the organization of cholinergic and noncholinergic projections from the BF to the parahippocampal cortex is more complex than previously described. J. Comp. Neurol. 524:2503-2515, 2016. © 2016 Wiley Periodicals, Inc. PMID:26780730

  19. Laminar pattern of cholinergic and adrenergic receptors in rat visual cortex using quantitative receptor autoradiography

    International Nuclear Information System (INIS)

    The laminar distribution of muscarinic acetylcholine receptors, including the M1-receptor subtype, of beta-adrenergic receptors, and noradrenaline uptake sites, was studied in the adult rat visual, frontal, somatosensory and motor cortex, using quantitative receptor autoradiography. In the visual cortex, the highest density of muscarinic acetylcholine receptors was found in layer I. From layer II/III to layer V binding decreases continueously reaching a constant binding level in layers V and VI. This laminar pattern of muscarinic receptor density differs somewhat from that observed in the non-visual cortical regions examined: layer II/III contained the highest receptor density followed by layer I and IV: lowest density was found in layer V and VI. The binding profile of the muscarinic cholinergic M1-subtype through the visual cortex shows a peak in cortical layer II and in the upper part of layer VI, whereas in the non-visual cortical regions cited the binding level was high in layer II/III, moderate in layer I and IV, and low in layer VI. Layers I to IV of the visual cortex contained the highest beta-adrenergic receptor densities, whereas only low binding levels were observed in the deeper layers. A similar laminar distribution was found also in the frontal, somatosensory and motor cortex. The density of noradrenaline uptake sites was high in all layers of the cortical regions studied, but with noradrenaline uptake sites somewhat more concentrated in the superficial layers than in deeper ones. The distinct laminar pattern of cholinergic and noradrenergic receptor sites indicates a different role for acetylcholine and noradrenaline in the functional anatomy of the cerebral cortex, and in particular, the visual cortex. (author)

  20. 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