Journal articles on the topic 'Mouse higher order visual cortical areas'
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Ruiz-Mejias, Marcel, Laura Ciria-Suarez, Maurizio Mattia, and Maria V. Sanchez-Vives. "Slow and fast rhythms generated in the cerebral cortex of the anesthetized mouse." Journal of Neurophysiology 106, no. 6 (December 2011): 2910–21. http://dx.doi.org/10.1152/jn.00440.2011.
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A characterization of the oscillatory activity in the cerebral cortex of the mouse was realized under ketamine anesthesia. Bilateral recordings were obtained from deep layers of primary visual, somatosensory, motor, and medial prefrontal cortex. A slow oscillatory activity consisting of up and down states was detected, the average frequency being 0.97 Hz in all areas. Different parameters of the oscillation were estimated across cortical areas, including duration of up and down states and their variability, speed of state transitions, and population firing rate. Similar values were obtained for all areas except for prefrontal cortex, which showed significant faster down-to-up state transitions, higher firing rate during up states, and more regular cycles. The wave propagation patterns in the anteroposterior axis in motor cortex and the mediolateral axis in visual cortex were studied with multielectrode recordings, yielding speed values between 8 and 93 mm/s. The firing of single units was analyzed with respect to the population activity. The most common pattern was that of neurons firing in >90% of the up states with 1–6 spikes. Finally, fast rhythms (beta, low gamma, and high gamma) were analyzed, all of them showing significantly larger power during up states than in down states. Prefrontal cortex exhibited significantly larger power in both beta and gamma bands (up to 1 order of magnitude larger in the case of high gamma) than the rest of the cortical areas. This study allows us to carry out interareal comparisons and provides a baseline to compare against cortical emerging activity from genetically altered animals.
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Andermann, Mark L., Aaron M. Kerlin, Demetris K. Roumis, Lindsey L. Glickfeld, and R. Clay Reid. "Functional Specialization of Mouse Higher Visual Cortical Areas." Neuron 72, no. 6 (December 2011): 1025–39. http://dx.doi.org/10.1016/j.neuron.2011.11.013.
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Glickfeld, Lindsey L., and Shawn R. Olsen. "Higher-Order Areas of the Mouse Visual Cortex." Annual Review of Vision Science 3, no. 1 (September 15, 2017): 251–73. http://dx.doi.org/10.1146/annurev-vision-102016-061331.
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Rhim, Issac, Gabriela Coello-Reyes, Hee-Kyoung Ko, and Ian Nauhaus. "Maps of cone opsin input to mouse V1 and higher visual areas." Journal of Neurophysiology 117, no. 4 (April 1, 2017): 1674–82. http://dx.doi.org/10.1152/jn.00849.2016.
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Studies in the mouse retina have characterized the spatial distribution of an anisotropic ganglion cell and photoreceptor mosaic, which provides a solid foundation to study how the cortex pools from afferent parallel color channels. In particular, the mouse’s retinal mosaic exhibits a gradient of wavelength sensitivity along its dorsoventral axis. Cones at the ventral extreme mainly express S opsin, which is sensitive to ultraviolet (UV) wavelengths. Then, moving toward the retina’s dorsal extreme, there is a transition to M-opsin dominance. Here, we tested the hypothesis that the retina’s opsin gradient is recapitulated in cortical visual areas as a functional map of wavelength sensitivity. We first identified visual areas in each mouse by mapping retinotopy with intrinsic signal imaging (ISI). Next, we measured ISI responses to stimuli along different directions of the S- and M-color plane to quantify the magnitude of S and M input to each location of the retinotopic maps in five visual cortical areas (V1, AL, LM, PM, and RL). The results illustrate a significant change in the S:M-opsin input ratio along the axis of vertical retinotopy that is consistent with the gradient along the dorsoventral axis of the retina. In particular, V1 populations encoding the upper visual field responded to S-opsin contrast with 6.1-fold greater amplitude than to M-opsin contrast. V1 neurons encoding lower fields responded with 4.6-fold greater amplitude to M- than S-opsin contrast. The maps in V1 and higher visual areas (HVAs) underscore the significance of a wavelength sensitivity gradient for guiding the mouse’s behavior. NEW & NOTEWORTHY Two elements of this study are particularly novel. For one, it is the first to quantify cone inputs to mouse visual cortex; we have measured cone input in five visual areas. Next, it is the first study to identify a feature map in the mouse visual cortex that is based on well-characterized anisotropy of cones in the retina; we have identified maps of opsin selectivity in five visual areas.
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Jin, Miaomiao, and Lindsey L. Glickfeld. "Magnitude, time course, and specificity of rapid adaptation across mouse visual areas." Journal of Neurophysiology 124, no. 1 (July 1, 2020): 245–58. http://dx.doi.org/10.1152/jn.00758.2019.
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Rapid adaptation dynamically alters sensory signals to account for recent experience. To understand how adaptation affects sensory processing and perception, we must determine how it impacts the diverse set of cortical and subcortical areas along the hierarchy of the mouse visual system. We find that rapid adaptation strongly impacts neurons in primary visual cortex, the higher visual areas, and the colliculus, consistent with its profound effects on behavior.
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Froudarakis, Emmanouil, Paul G. Fahey, Jacob Reimer, Stelios M. Smirnakis, Edward J. Tehovnik, and Andreas S. Tolias. "The Visual Cortex in Context." Annual Review of Vision Science 5, no. 1 (September 15, 2019): 317–39. http://dx.doi.org/10.1146/annurev-vision-091517-034407.
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In this article, we review the anatomical inputs and outputs to the mouse primary visual cortex, area V1. Our survey of data from the Allen Institute Mouse Connectivity project indicates that mouse V1 is highly interconnected with both cortical and subcortical brain areas. This pattern of innervation allows for computations that depend on the state of the animal and on behavioral goals, which contrasts with simple feedforward, hierarchical models of visual processing. Thus, to have an accurate description of the function of V1 during mouse behavior, its involvement with the rest of the brain circuitry has to be considered. Finally, it remains an open question whether the primary visual cortex of higher mammals displays the same degree of sensorimotor integration in the early visual system.
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Chou, Shen-Ju, Zoila Babot, Axel Leingärtner, Michele Studer, Yasushi Nakagawa, and Dennis D. M. O'Leary. "Geniculocortical Input Drives Genetic Distinctions Between Primary and Higher-Order Visual Areas." Science 340, no. 6137 (June 6, 2013): 1239–42. http://dx.doi.org/10.1126/science.1232806.
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Studies of area patterning of the neocortex have focused on primary areas, concluding that the primary visual area, V1, is specified by transcription factors (TFs) expressed by progenitors. Mechanisms that determine higher-order visual areas (VHO) and distinguish them from V1 are unknown. We demonstrated a requirement for thalamocortical axon (TCA) input by genetically deleting geniculocortical TCAs and showed that they drive differentiation of patterned gene expression that distinguishes V1 and VHO. Our findings suggest a multistage process for area patterning: TFs expressed by progenitors specify an occipital visual cortical field that differentiates into V1 and VHO; this latter phase requires geniculocortical TCA input to the nascent V1 that determines genetic distinctions between V1 and VHO for all layers and ultimately determines their area-specific functional properties.
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Merabet, Lotfi B., Jascha D. Swisher, Stephanie A. McMains, Mark A. Halko, Amir Amedi, Alvaro Pascual-Leone, and David C. Somers. "Combined Activation and Deactivation of Visual Cortex During Tactile Sensory Processing." Journal of Neurophysiology 97, no. 2 (February 2007): 1633–41. http://dx.doi.org/10.1152/jn.00806.2006.
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The involvement of occipital cortex in sensory processing is not restricted solely to the visual modality. Tactile processing has been shown to modulate higher-order visual and multisensory integration areas in sighted as well as visually deprived subjects; however, the extent of involvement of early visual cortical areas remains unclear. To investigate this issue, we employed functional magnetic resonance imaging in normally sighted, briefly blindfolded subjects with well-defined visuotopic borders as they tactually explored and rated raised-dot patterns. Tactile task performance resulted in significant activation in primary visual cortex (V1) and deactivation of extrastriate cortical regions V2, V3, V3A, and hV4 with greater deactivation in dorsal subregions and higher visual areas. These results suggest that tactile processing affects occipital cortex via two distinct pathways: a suppressive top-down pathway descending through the visual cortical hierarchy and an excitatory pathway arising from outside the visual cortical hierarchy that drives area V1 directly.
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Huang, Jie, Paul Beach, Andrea Bozoki, and David C. Zhu. "Alzheimer’s Disease Progressively Alters the Face-Evoked Visual-Processing Network." Journal of Alzheimer's Disease 77, no. 3 (September 29, 2020): 1025–42. http://dx.doi.org/10.3233/jad-200173.
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Background: Postmortem studies of Alzheimer’s disease (AD) brains not only find amyloid-β (Aβ) and neurofibrillary tangles (NFT) in the primary and associative visual cortical areas, but also reveal a temporally successive sequence of AD pathology beginning in higher-order visual association areas, followed by involvement of lower-order visual processing regions with disease progression, and extending to primary visual cortex in late-stage disease. These findings suggest that neuronal loss associated with Aβ and NFT aggregation in these areas may alter not only the local neuronal activation but also visual neural network activity. Objective: Applying a novel method to identify the visual functional network and investigate the association of the network changes with disease progression. Methods: To investigate the effect of AD on the face-evoked visual-processing network, 8 severe AD (SAD) patients, 11 mild/moderate AD (MAD), and 26 healthy senior (HS) controls undertook a task-fMRI study of viewing face photos. Results: For the HS, the identified group-mean visual-processing network in the ventral pathway started from V1 and ended within the fusiform gyrus. In contrast, this network was disrupted and reduced in the AD patients in a disease-severity dependent manner: for the MAD patients, the network was disrupted and reduced mainly in the higher-order visual association areas; for the SAD patients, the network was nearly absent in the higher-order association areas, and disrupted and reduced in the lower-order areas. Conclusion: This finding is consistent with the current canonical view of the temporally successive sequence of AD pathology through visual cortical areas.
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Orban, Guy A. "Higher Order Visual Processing in Macaque Extrastriate Cortex." Physiological Reviews 88, no. 1 (January 2008): 59–89. http://dx.doi.org/10.1152/physrev.00008.2007.
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The extrastriate cortex of primates encompasses a substantial portion of the cerebral cortex and is devoted to the higher order processing of visual signals and their dispatch to other parts of the brain. A first step towards the understanding of the function of this cortical tissue is a description of the selectivities of the various neuronal populations for higher order aspects of the image. These selectivities present in the various extrastriate areas support many diverse representations of the scene before the subject. The list of the known selectivities includes that for pattern direction and speed gradients in middle temporal/V5 area; for heading in medial superior temporal visual area, dorsal part; for orientation of nonluminance contours in V2 and V4; for curved boundary fragments in V4 and shape parts in infero-temporal area (IT); and for curvature and orientation in depth from disparity in IT and CIP. The most common putative mechanism for generating such emergent selectivity is the pattern of excitatory and inhibitory linear inputs from the afferent area combined with nonlinear mechanisms in the afferent and receiving area.
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Kumar, Mari Ganesh, Ming Hu, Aadhirai Ramanujan, Mriganka Sur, and Hema A. Murthy. "Functional parcellation of mouse visual cortex using statistical techniques reveals response-dependent clustering of cortical processing areas." PLOS Computational Biology 17, no. 2 (February 4, 2021): e1008548. http://dx.doi.org/10.1371/journal.pcbi.1008548.
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The visual cortex of the mouse brain can be divided into ten or more areas that each contain complete or partial retinotopic maps of the contralateral visual field. It is generally assumed that these areas represent discrete processing regions. In contrast to the conventional input-output characterizations of neuronal responses to standard visual stimuli, here we asked whether six of the core visual areas have responses that are functionally distinct from each other for a given visual stimulus set, by applying machine learning techniques to distinguish the areas based on their activity patterns. Visual areas defined by retinotopic mapping were examined using supervised classifiers applied to responses elicited by a range of stimuli. Using two distinct datasets obtained using wide-field and two-photon imaging, we show that the area labels predicted by the classifiers were highly consistent with the labels obtained using retinotopy. Furthermore, the classifiers were able to model the boundaries of visual areas using resting state cortical responses obtained without any overt stimulus, in both datasets. With the wide-field dataset, clustering neuronal responses using a constrained semi-supervised classifier showed graceful degradation of accuracy. The results suggest that responses from visual cortical areas can be classified effectively using data-driven models. These responses likely reflect unique circuits within each area that give rise to activity with stronger intra-areal than inter-areal correlations, and their responses to controlled visual stimuli across trials drive higher areal classification accuracy than resting state responses.
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FITZGIBBON, THOMAS, BRETT A. SZMAJDA, and PAUL R. MARTIN. "First order connections of the visual sector of the thalamic reticular nucleus in marmoset monkeys (Callithrix jacchus)." Visual Neuroscience 24, no. 6 (November 2007): 857–74. http://dx.doi.org/10.1017/s0952523807070770.
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The thalamic reticular nucleus (TRN) supplies an important inhibitory input to the dorsal thalamus. Previous studies in non-primate mammals have suggested that the visual sector of the TRN has a lateral division, which has connections with first-order (primary) sensory thalamic and cortical areas, and a medial division, which has connections with higher-order (association) thalamic and cortical areas. However, the question whether the primate TRN is segregated in the same manner is controversial. Here, we investigated the connections of the TRN in a New World primate, the marmoset (Callithrix jacchus). The topography of labeled cells and terminals was analyzed following iontophoretic injections of tracers into the primary visual cortex (V1) or the dorsal lateral geniculate nucleus (LGNd). The results show that rostroventral TRN, adjacent to the LGNd, is primarily connected with primary visual areas, while the most caudal parts of the TRN are associated with higher order visual thalamic areas. A small region of the TRN near the caudal pole of the LGNd (foveal representation) contains connections where first (lateral TRN) and higher order visual areas (medial TRN) overlap. Reciprocal connections between LGNd and TRN are topographically organized, so that a series of rostrocaudal injections within the LGNd labeled cells and terminals in the TRN in a pattern shaped like rostrocaudal overlapping “fish scales.” We propose that the dorsal areas of the TRN, adjacent to the top of the LGNd, represent the lower visual field (connected with medial LGNd), and the more ventral parts of the TRN contain a map representing the upper visual field (connected with lateral LGNd).
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De Pasquale, Roberto, and S. Murray Sherman. "A modulatory effect of the feedback from higher visual areas to V1 in the mouse." Journal of Neurophysiology 109, no. 10 (May 15, 2013): 2618–31. http://dx.doi.org/10.1152/jn.01083.2012.
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Using a mouse brain slice preparation, we studied the modulatory effects of a feedback projection from higher visual cortical areas, mostly or exclusively area LM (or V2), on two inputs to layer 4 cells in the first visual area (V1). The two inputs to these cells were geniculocortical and an unspecified intracortical input, possibly involving layer 6 cells. We found that activation of metabotropic glutamate receptors (mGluRs) from stimulation of the feedback projection reduced the evoked excitatory postsynaptic currents of both of these inputs to layer 4 but that this modulation acts in an input-specific way. Reducing the strength of the geniculocortical input in adults involved both presynaptic and postsynaptic group I mGluRs (although in younger animals presynaptic group II mGluRs were also involved), whereas modulation of the intracortical input acted entirely via postsynaptic group II mGluRs. These results demonstrate that one of the effects of this feedback pathway is to control the gain of geniculocortical transmission.
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GILBERT, CHARLES D. "Adult Cortical Dynamics." Physiological Reviews 78, no. 2 (April 1, 1998): 467–85. http://dx.doi.org/10.1152/physrev.1998.78.2.467.
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Gilbert, Charles D. Adult Cortical Dynamics. Physiol. Rev. 78: 467–485, 1998. — There are many influences on our perception of local features. What we see is not strictly a reflection of the physical characteristics of a scene but instead is highly dependent on the processes by which our brain attempts to interpret the scene. As a result, our percepts are shaped by the context within which local features are presented, by our previous visual experiences, operating over a wide range of time scales, and by our expectation of what is before us. The substrate for these influences is likely to be found in the lateral interactions operating within individual areas of the cerebral cortex and in the feedback from higher to lower order cortical areas. Even at early stages in the visual pathway, cells are far more flexible in their functional properties than previously thought. It had long been assumed that cells in primary visual cortex had fixed properties, passing along the product of a stereotyped operation to the next stage in the visual pathway. Any plasticity dependent on visual experience was thought to be restricted to a period early in the life of the animal, the critical period. Furthermore, the assembly of contours and surfaces into unified percepts was assumed to take place at high levels in the visual pathway, whereas the receptive fields of cells in primary visual cortex represented very small windows on the visual scene. These concepts of spatial integration and plasticity have been radically modified in the past few years. The emerging view is that even at the earliest stages in the cortical processing of visual information, cells are highly mutable in their functional properties and are capable of integrating information over a much larger part of visual space than originally believed.
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Leh, Sandra E., M. Mallar Chakravarty, and Alain Ptito. "The Connectivity of the Human Pulvinar: A Diffusion Tensor Imaging Tractography Study." International Journal of Biomedical Imaging 2008 (2008): 1–5. http://dx.doi.org/10.1155/2008/789539.
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Previous studies in nonhuman primates and cats have shown that the pulvinar receives input from various cortical and subcortical areas involved in vision. Although the contribution of the pulvinar to human vision remains to be established, anatomical tracer and electrophysiological animal studies on cortico-pulvinar circuits suggest an important role of this structure in visual spatial attention, visual integration, and higher-order visual processing. Because methodological constraints limit investigations of the human pulvinar's function, its role could, up to now, only be inferred from animal studies. In the present study, we used an innovative imaging technique, Diffusion Tensor Imaging (DTI) tractography, to determine cortical and subcortical connections of the human pulvinar. We were able to reconstruct pulvinar fiber tracts and compare variability across subjects in vivo. Here we demonstrate that the human pulvinar is interconnected with subcortical structures (superior colliculus, thalamus, and caudate nucleus) as well as with cortical regions (primary visual areas (area 17), secondary visual areas (area 18, 19), visual inferotemporal areas (area 20), posterior parietal association areas (area 7), frontal eye fields and prefrontal areas). These results are consistent with the connectivity reported in animal anatomical studies.
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Rosa, Marcello G. P., and Rowan Tweedale. "Brain maps, great and small: lessons from comparative studies of primate visual cortical organization." Philosophical Transactions of the Royal Society B: Biological Sciences 360, no. 1456 (April 29, 2005): 665–91. http://dx.doi.org/10.1098/rstb.2005.1626.
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In this paper, we review evidence from comparative studies of primate cortical organization, highlighting recent findings and hypotheses that may help us to understand the rules governing evolutionary changes of the cortical map and the process of formation of areas during development. We argue that clear unequivocal views of cortical areas and their homologies are more likely to emerge for ‘core’ fields, including the primary sensory areas, which are specified early in development by precise molecular identification steps. In primates, the middle temporal area is probably one of these primordial cortical fields. Areas that form at progressively later stages of development correspond to progressively more recent evolutionary events, their development being less firmly anchored in molecular specification. The certainty with which areal boundaries can be delimited, and likely homologies can be assigned, becomes increasingly blurred in parallel with this evolutionary/developmental sequence. For example, while current concepts for the definition of cortical areas have been vindicated in allowing a clarification of the organization of the New World monkey ‘third tier’ visual cortex (the third and dorsomedial areas, V3 and DM), our analyses suggest that more flexible mapping criteria may be needed to unravel the organization of higher-order visual association and polysensory areas.
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Li, Jennifer Y., Charles A. Hass, Ian Matthews, Amy C. Kristl, and Lindsey L. Glickfeld. "Distinct recruitment of feedforward and recurrent pathways across higher-order areas of mouse visual cortex." Current Biology 31, no. 22 (November 2021): 5024–36. http://dx.doi.org/10.1016/j.cub.2021.09.042.
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Convento, Silvia, Giuseppe Vallar, Chiara Galantini, and Nadia Bolognini. "Neuromodulation of Early Multisensory Interactions in the Visual Cortex." Journal of Cognitive Neuroscience 25, no. 5 (May 2013): 685–96. http://dx.doi.org/10.1162/jocn_a_00347.
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Merging information derived from different sensory channels allows the brain to amplify minimal signals to reduce their ambiguity, thereby improving the ability of orienting to, detecting, and identifying environmental events. Although multisensory interactions have been mostly ascribed to the activity of higher-order heteromodal areas, multisensory convergence may arise even in primary sensory-specific areas located very early along the cortical processing stream. In three experiments, we investigated early multisensory interactions in lower-level visual areas, by using a novel approach, based on the coupling of behavioral stimulation with two noninvasive brain stimulation techniques, namely, TMS and transcranial direct current stimulation (tDCS). First, we showed that redundant multisensory stimuli can increase visual cortical excitability, as measured by means of phosphene induction by occipital TMS; such physiological enhancement is followed by a behavioral facilitation through the amplification of signal intensity in sensory-specific visual areas. The more sensory inputs are combined (i.e., trimodal vs. bimodal stimuli), the greater are the benefits on phosphene perception. Second, neuroelectrical activity changes induced by tDCS in the temporal and in the parietal cortices, but not in the occipital cortex, can further boost the multisensory enhancement of visual cortical excitability, by increasing the auditory and tactile inputs from temporal and parietal regions, respectively, to lower-level visual areas.
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Pasupathy, Anitha, Dina V. Popovkina, and Taekjun Kim. "Visual Functions of Primate Area V4." Annual Review of Vision Science 6, no. 1 (September 15, 2020): 363–85. http://dx.doi.org/10.1146/annurev-vision-030320-041306.
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Area V4—the focus of this review—is a mid-level processing stage along the ventral visual pathway of the macaque monkey. V4 is extensively interconnected with other visual cortical areas along the ventral and dorsal visual streams, with frontal cortical areas, and with several subcortical structures. Thus, it is well poised to play a broad and integrative role in visual perception and recognition—the functional domain of the ventral pathway. Neurophysiological studies in monkeys engaged in passive fixation and behavioral tasks suggest that V4 responses are dictated by tuning in a high-dimensional stimulus space defined by form, texture, color, depth, and other attributes of visual stimuli. This high-dimensional tuning may underlie the development of object-based representations in the visual cortex that are critical for tracking, recognizing, and interacting with objects. Neurophysiological and lesion studies also suggest that V4 responses are important for guiding perceptual decisions and higher-order behavior.
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Strappini, Francesca, Meytal Wilf, Ofer Karp, Hagar Goldberg, Michal Harel, Edna Furman-Haran, Tal Golan, and Rafael Malach. "Resting-State Activity in High-Order Visual Areas as a Window into Natural Human Brain Activations." Cerebral Cortex 29, no. 9 (November 3, 2018): 3618–35. http://dx.doi.org/10.1093/cercor/bhy242.
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Abstract A major limitation of conventional human brain research has been its basis in highly artificial laboratory experiments. Due to technical constraints, little is known about the nature of cortical activations during ecological real life. We have previously proposed the “spontaneous trait reactivation (STR)” hypothesis arguing that resting-state patterns, which emerge spontaneously in the absence of external stimulus, reflect the statistics of habitual cortical activations during real life. Therefore, these patterns can serve as a window into daily life cortical activity. A straightforward prediction of this hypothesis is that spontaneous patterns should preferentially correlate to patterns generated by naturalistic stimuli compared with artificial ones. Here we targeted high-level category-selective visual areas and tested this prediction by comparing BOLD functional connectivity patterns formed during rest to patterns formed in response to naturalistic stimuli, as well as to more artificial category-selective, dynamic stimuli. Our results revealed a significant correlation between the resting-state patterns and functional connectivity patterns generated by naturalistic stimuli. Furthermore, the correlations to naturalistic stimuli were significantly higher than those found between resting-state patterns and those generated by artificial control stimuli. These findings provide evidence of a stringent link between spontaneous patterns and the activation patterns during natural vision.
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Danka Mohammed, Chand Parvez. "Differential Circuit Mechanisms of Young and Aged Visual Cortex in the Mammalian Brain." NeuroSci 2, no. 1 (January 4, 2021): 1–26. http://dx.doi.org/10.3390/neurosci2010001.
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The main goal of this review is to summarize and discuss (1) age-dependent structural reorganization of mammalian visual cortical circuits underlying complex visual behavior functions in primary visual cortex (V1) and multiple extrastriate visual areas, and (2) current evidence supporting the notion of compensatory mechanisms in aged visual circuits as well as the use of rehabilitative therapy for the recovery of neural plasticity in normal and diseased aging visual circuit mechanisms in different species. It is well known that aging significantly modulates both the structural and physiological properties of visual cortical neurons in V1 and other visual cortical areas in various species. Compensatory aged neural mechanisms correlate with the complexity of visual functions; however, they do not always result in major circuit alterations resulting in age-dependent decline in performance of a visual task or neurodegenerative disorders. Computational load and neural processing gradually increase with age, and the complexity of compensatory mechanisms correlates with the intricacy of higher form visual perceptions that are more evident in higher-order visual areas. It is particularly interesting to note that the visual perceptual processing of certain visual behavior functions does not change with age. This review aims to comprehensively discuss the effect of normal aging on neuroanatomical alterations that underlie critical visual functions and more importantly to highlight differences between compensatory mechanisms in aged neural circuits and neural processes related to visual disorders. This type of approach will further enhance our understanding of inter-areal and cortico-cortical connectivity of visual circuits in normal aging and identify major circuit alterations that occur in different visual deficits, thus facilitating the design and evaluation of potential rehabilitation therapies as well as the assessment of the extent of their rejuvenation.
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Sellers, Kristin K., Davis V. Bennett, Axel Hutt, James H. Williams, and Flavio Fröhlich. "Awake vs. anesthetized: layer-specific sensory processing in visual cortex and functional connectivity between cortical areas." Journal of Neurophysiology 113, no. 10 (June 2015): 3798–815. http://dx.doi.org/10.1152/jn.00923.2014.
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During general anesthesia, global brain activity and behavioral state are profoundly altered. Yet it remains mostly unknown how anesthetics alter sensory processing across cortical layers and modulate functional cortico-cortical connectivity. To address this gap in knowledge of the micro- and mesoscale effects of anesthetics on sensory processing in the cortical microcircuit, we recorded multiunit activity and local field potential in awake and anesthetized ferrets ( Mustela putoris furo) during sensory stimulation. To understand how anesthetics alter sensory processing in a primary sensory area and the representation of sensory input in higher-order association areas, we studied the local sensory responses and long-range functional connectivity of primary visual cortex (V1) and prefrontal cortex (PFC). Isoflurane combined with xylazine provided general anesthesia for all anesthetized recordings. We found that anesthetics altered the duration of sensory-evoked responses, disrupted the response dynamics across cortical layers, suppressed both multimodal interactions in V1 and sensory responses in PFC, and reduced functional cortico-cortical connectivity between V1 and PFC. Together, the present findings demonstrate altered sensory responses and impaired functional network connectivity during anesthesia at the level of multiunit activity and local field potential across cortical layers.
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Halgren, Milan, István Ulbert, Hélène Bastuji, Dániel Fabó, Lorand Erőss, Marc Rey, Orrin Devinsky, et al. "The generation and propagation of the human alpha rhythm." Proceedings of the National Academy of Sciences 116, no. 47 (November 4, 2019): 23772–82. http://dx.doi.org/10.1073/pnas.1913092116.
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The alpha rhythm is the longest-studied brain oscillation and has been theorized to play a key role in cognition. Still, its physiology is poorly understood. In this study, we used microelectrodes and macroelectrodes in surgical epilepsy patients to measure the intracortical and thalamic generators of the alpha rhythm during quiet wakefulness. We first found that alpha in both visual and somatosensory cortex propagates from higher-order to lower-order areas. In posterior cortex, alpha propagates from higher-order anterosuperior areas toward the occipital pole, whereas alpha in somatosensory cortex propagates from associative regions toward primary cortex. Several analyses suggest that this cortical alpha leads pulvinar alpha, complicating prevailing theories of a thalamic pacemaker. Finally, alpha is dominated by currents and firing in supragranular cortical layers. Together, these results suggest that the alpha rhythm likely reflects short-range supragranular feedback, which propagates from higher- to lower-order cortex and cortex to thalamus. These physiological insights suggest how alpha could mediate feedback throughout the thalamocortical system.
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Huang, Jie, Paul Beach, Andrea Bozoki, and David C. Zhu. "Alzheimer’s Disease Progressively Reduces Visual Functional Network Connectivity." Journal of Alzheimer's Disease Reports 5, no. 1 (July 8, 2021): 549–62. http://dx.doi.org/10.3233/adr-210017.
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Background: Postmortem studies of brains with Alzheimer’s disease (AD) not only find amyloid-beta (Aβ) and neurofibrillary tangles (NFT) in the visual cortex, but also reveal temporally sequential changes in AD pathology from higher-order association areas to lower-order areas and then primary visual area (V1) with disease progression. Objective: This study investigated the effect of AD severity on visual functional network. Methods: Eight severe AD (SAD) patients, 11 mild/moderate AD (MAD), and 26 healthy senior (HS) controls undertook a resting-state fMRI (rs-fMRI) and a task fMRI of viewing face photos. A resting-state visual functional connectivity (FC) network and a face-evoked visual-processing network were identified for each group. Results: For the HS, the identified group-mean face-evoked visual-processing network in the ventral pathway started from V1 and ended within the fusiform gyrus. In contrast, the resting-state visual FC network was mainly confined within the visual cortex. AD disrupted these two functional networks in a similar severity dependent manner: the more severe the cognitive impairment, the greater reduction in network connectivity. For the face-evoked visual-processing network, MAD disrupted and reduced activation mainly in the higher-order visual association areas, with SAD further disrupting and reducing activation in the lower-order areas. Conclusion: These findings provide a functional corollary to the canonical view of the temporally sequential advancement of AD pathology through visual cortical areas. The association of the disruption of functional networks, especially the face-evoked visual-processing network, with AD severity suggests a potential predictor or biomarker of AD progression.
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Gallivan, Jason P., Craig S. Chapman, Daniel J. Gale, J. Randall Flanagan, and Jody C. Culham. "Selective Modulation of Early Visual Cortical Activity by Movement Intention." Cerebral Cortex 29, no. 11 (January 21, 2019): 4662–78. http://dx.doi.org/10.1093/cercor/bhy345.
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Abstract The primate visual system contains myriad feedback projections from higher- to lower-order cortical areas, an architecture that has been implicated in the top-down modulation of early visual areas during working memory and attention. Here we tested the hypothesis that these feedback projections also modulate early visual cortical activity during the planning of visually guided actions. We show, across three separate human functional magnetic resonance imaging (fMRI) studies involving object-directed movements, that information related to the motor effector to be used (i.e., limb, eye) and action goal to be performed (i.e., grasp, reach) can be selectively decoded—prior to movement—from the retinotopic representation of the target object(s) in early visual cortex. We also find that during the planning of sequential actions involving objects in two different spatial locations, that motor-related information can be decoded from both locations in retinotopic cortex. Together, these findings indicate that movement planning selectively modulates early visual cortical activity patterns in an effector-specific, target-centric, and task-dependent manner. These findings offer a neural account of how motor-relevant target features are enhanced during action planning and suggest a possible role for early visual cortex in instituting a sensorimotor estimate of the visual consequences of movement.
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Matsuzaki, Naoyuki, Csaba Juhász, and Eishi Asano. "Cortico-cortical evoked potentials and stimulation-elicited gamma activity preferentially propagate from lower- to higher-order visual areas." Clinical Neurophysiology 124, no. 7 (July 2013): 1290–96. http://dx.doi.org/10.1016/j.clinph.2013.02.007.
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Jiang, Fang, Laurence Dricot, Jochen Weber, Giulia Righi, Michael J. Tarr, Rainer Goebel, and Bruno Rossion. "Face categorization in visual scenes may start in a higher order area of the right fusiform gyrus: evidence from dynamic visual stimulation in neuroimaging." Journal of Neurophysiology 106, no. 5 (November 2011): 2720–36. http://dx.doi.org/10.1152/jn.00672.2010.
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How a visual stimulus is initially categorized as a face by the cortical face-processing network remains largely unclear. In this study we used functional MRI to study the dynamics of face detection in visual scenes by using a paradigm in which scenes containing faces or cars are revealed progressively as they emerge from visual noise. Participants were asked to respond as soon as they detected a face or car during the noise sequence. Among the face-sensitive regions identified based on a standard localizer, a high-level face-sensitive area, the right fusiform face area (FFA), showed the earliest difference between face and car activation. Critically, differential activation in FFA was observed before differential activation in the more posteriorly located occipital face area (OFA). A whole brain analysis confirmed these findings, with a face-sensitive cluster in the right fusiform gyrus being the only cluster showing face preference before successful behavioral detection. Overall, these findings indicate that following generic low-level visual analysis, a face stimulus presented in a gradually revealed visual scene is first detected in the right middle fusiform gyrus, only after which further processing spreads to a network of cortical and subcortical face-sensitive areas (including the posteriorly located OFA). These results provide further evidence for a nonhierarchical organization of the cortical face-processing network.
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Vaiceliunaite, Agne, Sinem Erisken, Florian Franzen, Steffen Katzner, and Laura Busse. "Spatial integration in mouse primary visual cortex." Journal of Neurophysiology 110, no. 4 (August 15, 2013): 964–72. http://dx.doi.org/10.1152/jn.00138.2013.
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Responses of many neurons in primary visual cortex (V1) are suppressed by stimuli exceeding the classical receptive field (RF), an important property that might underlie the computation of visual saliency. Traditionally, it has proven difficult to disentangle the underlying neural circuits, including feedforward, horizontal intracortical, and feedback connectivity. Since circuit-level analysis is particularly feasible in the mouse, we asked whether neural signatures of spatial integration in mouse V1 are similar to those of higher-order mammals and investigated the role of parvalbumin-expressing (PV+) inhibitory interneurons. Analogous to what is known from primates and carnivores, we demonstrate that, in awake mice, surround suppression is present in the majority of V1 neurons and is strongest in superficial cortical layers. Anesthesia with isoflurane-urethane, however, profoundly affects spatial integration: it reduces the laminar dependency, decreases overall suppression strength, and alters the temporal dynamics of responses. We show that these effects of brain state can be parsimoniously explained by assuming that anesthesia affects contrast normalization. Hence, the full impact of suppressive influences in mouse V1 cannot be studied under anesthesia with isoflurane-urethane. To assess the neural circuits of spatial integration, we targeted PV+ interneurons using optogenetics. Optogenetic depolarization of PV+ interneurons was associated with increased RF size and decreased suppression in the recorded population, similar to effects of lowering stimulus contrast, suggesting that PV+ interneurons contribute to spatial integration by affecting overall stimulus drive. We conclude that the mouse is a promising model for circuit-level mechanisms of spatial integration, which relies on the combined activity of different types of inhibitory interneurons.
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Hang, Giao B., and Yang Dan. "Asymmetric Temporal Integration of Layer 4 and Layer 2/3 Inputs in Visual Cortex." Journal of Neurophysiology 105, no. 1 (January 2011): 347–55. http://dx.doi.org/10.1152/jn.00159.2010.
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Neocortical neurons in vivo receive concurrent synaptic inputs from multiple sources, including feedforward, horizontal, and feedback pathways. Layer 2/3 of the visual cortex receives feedforward input from layer 4 and horizontal input from layer 2/3. Firing of the pyramidal neurons, which carries the output to higher cortical areas, depends critically on the interaction of these pathways. Here we examined synaptic integration of inputs from layer 4 and layer 2/3 in rat visual cortical slices. We found that the integration is sublinear and temporally asymmetric, with larger responses if layer 2/3 input preceded layer 4 input. The sublinearity depended on inhibition, and the asymmetry was largely attributable to the difference between the two inhibitory inputs. Interestingly, the asymmetric integration was specific to pyramidal neurons, and it strongly affected their spiking output. Thus via cortical inhibition, the temporal order of activation of layer 2/3 and layer 4 pathways can exert powerful control of cortical output during visual processing.
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Regev, Mor, Erez Simony, Katherine Lee, Kean Ming Tan, Janice Chen, and Uri Hasson. "Propagation of Information Along the Cortical Hierarchy as a Function of Attention While Reading and Listening to Stories." Cerebral Cortex 29, no. 10 (November 3, 2018): 4017–34. http://dx.doi.org/10.1093/cercor/bhy282.
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Abstract How does attention route information from sensory to high-order areas as a function of task, within the relatively fixed topology of the brain? In this study, participants were simultaneously presented with 2 unrelated stories—one spoken and one written—and asked to attend one while ignoring the other. We used fMRI and a novel intersubject correlation analysis to track the spread of information along the processing hierarchy as a function of task. Processing the unattended spoken (written) information was confined to auditory (visual) cortices. In contrast, attending to the spoken (written) story enhanced the stimulus-selective responses in sensory regions and allowed it to spread into higher-order areas. Surprisingly, we found that the story-specific spoken (written) responses for the attended story also reached secondary visual (auditory) regions of the unattended sensory modality. These results demonstrate how attention enhances the processing of attended input and allows it to propagate across brain areas.
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Hashimoto, Ritsuo, Asako Tagawa, Noriyo Komori, Tomoko Ogawa, and Hiroyuki Kato. "Transient Dyschromatopsia, Static Form Agnosia, and Prosopagnosia Observed in a Patient with Anti-NMDA Receptor Encephalitis." Case Reports in Neurological Medicine 2019 (April 2, 2019): 1–5. http://dx.doi.org/10.1155/2019/2929782.
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We presented a case of a 19-year-old woman who suffered from anti-N-methyl-D-aspartate (NMDA) receptor encephalitis associated with ovarian teratoma. The patient showed a variety of higher visual symptoms which changed over the recovery phase of the disease. In chronological order, she experienced cortical blindness, amblyopia, dyschromatopsia, static form agnosia, and prosopagnosia. Among these symptoms, the most intriguing was the static form agnosia. Although she could recognize the forms of moving objects, she could not make out those of stationary ones. All of these visual symptoms were transient, implying that she might have incidentally regained the function of the distinct cortical visual areas in the time course of follow-up. This case further suggests that visual functions concerned with the perceptions of static form and form-from-motion could be dissociable and may rely on distinct brain regions.
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Cuppini, Cristiano, Elisa Magosso, and Mauro Ursino. "A neurocomputational model of cortical auditory–visual illusions." Seeing and Perceiving 25 (2012): 115. http://dx.doi.org/10.1163/187847612x647487.
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The ability of the brain to integrate information from different sensory channels is fundamental to perceive the external world. Experimental findings suggest that multisensory interactions occur in the early processing stages in primary cortices, at the expense of the classical idea of independent sensory processing streams. However the underlying mechanisms are still not well known. The aim of the present endeavour was to develop a neural network model to analyse possible mechanisms and neural circuitries underlying perceptual audio–visual illusions, such as the Shams illusion and the ventriloquism effect. The model consists of two arrays of auditory and visual neurons topologically aligned. Neurons within each layer interact via excitatory and inhibitory lateral synapses, following a classical Mexican-hat disposition; moreover neurons in the two layers are reciprocally connected via one-to-one excitatory inter-area synapses. A fundamental point in the model is that the visual neurons exhibit a smaller spatial receptive field compared with the auditory ones (i.e., better spatial resolution) but a slower time constant (i.e., less accurate temporal precision). This is the only difference between the two areas. Simulations suggest that classic illusions (Sham effect and ventriloquism) can be explained by assuming direct excitatory synapses among the two regions, without the need of feedback projections from higher-order integrative regions. Moreover the model ascribes the sham illusion to the better temporal resolution of the auditory processing compared with the visual one. Similarly, the better spatial resolution of visual processing can explain the ventriloquism effect, with the same model structure and the same parameter values.
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Meredith, M. Alex, Mark T. Wallace, and H. Ruth Clemo. "Do the Different Sensory Areas Within the Cat Anterior Ectosylvian Sulcal Cortex Collectively Represent a Network Multisensory Hub?" Multisensory Research 31, no. 8 (2018): 793–823. http://dx.doi.org/10.1163/22134808-20181316.
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Abstract Current theory supports that the numerous functional areas of the cerebral cortex are organized and function as a network. Using connectional databases and computational approaches, the cerebral network has been demonstrated to exhibit a hierarchical structure composed of areas, clusters and, ultimately, hubs. Hubs are highly connected, higher-order regions that also facilitate communication between different sensory modalities. One computationally identified network hub is the visual area of the Anterior Ectosylvian Sulcal cortex (AESc) of the cat. The Anterior Ectosylvian Visual area (AEV) is but one component of the AESc since the latter also includes the auditory (Field of the Anterior Ectosylvian Sulcus — FAES) and somatosensory (Fourth somatosensory representation — SIV) areas. To better understand the nature of cortical network hubs, the present report reviews the biological features of the AESc. Within the AESc, each area has extensive external cortical connections as well as among one another. Each of these core representations is separated by a transition zone characterized by bimodal neurons that share sensory properties of both adjoining core areas. Finally, core and transition zones are underlain by a continuous sheet of layer 5 neurons that project to common output structures. Altogether, these shared properties suggest that the collective AESc region represents a multiple sensory/multisensory cortical network hub. Ultimately, such an interconnected, composite structure adds complexity and biological detail to the understanding of cortical network hubs and their function in cortical processing.
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Li, Zhen, and Hiroaki Shigemasu. "Unique Neural Activity Patterns Among Lower Order Cortices and Shared Patterns Among Higher Order Cortices During Processing of Similar Shapes With Different Stimulus Types." i-Perception 12, no. 3 (March 2021): 204166952110182. http://dx.doi.org/10.1177/20416695211018222.
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We investigated the neural mechanism of the processing of three-dimensional (3D) shapes defined by disparity and perspective. We measured blood oxygenation level-dependent signals as participants viewed and classified 3D images of convex–concave shapes. According to the cue (disparity or perspective) and element type (random dots or black and white dotted lines), three types of stimuli were used: random dot stereogram, black and white dotted lines with perspective, and black and white dotted lines with binocular disparity. The blood oxygenation level-dependent images were then classified by multivoxel pattern analysis. To identify areas selective to shape, we assessed convex–concave classification accuracy with classifiers trained and tested using signals evoked by the same stimulus type (same cue and element type). To identify cortical regions with similar neural activity patterns regardless of stimulus type, we assessed the convex–concave classification accuracy of transfer classification in which classifiers were trained and tested using different stimulus types (different cues or element types). Classification accuracy using the same stimulus type was high in the early visual areas and subregions of the intraparietal sulcus (IPS), whereas transfer classification accuracy was high in the dorsal subregions of the IPS. These results indicate that the early visual areas process the specific features of stimuli, whereas the IPS regions perform more generalized processing of 3D shapes, independent of a specific stimulus type.
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Malach, Rafael. "The Role of the Prefrontal Cortex in Conscious Perception: The Localist Perspective." Journal of Consciousness Studies 29, no. 7 (July 14, 2022): 93–114. http://dx.doi.org/10.53765/20512201.29.7.093.
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In recent years the role of the prefrontal cortex (PFC) in conscious perception has acquired great interest since it became a pivotal issue distinguishing among prevailing neuronal theories of human consciousness. One can identify three major, and conflicting, views of this role. The globalist view proposes that the PFC is a major hub in a global workspace whose activation is a critical component for any conscious experience. The higher-order thought theory argues that the PFC has a more specialized role underlying higher-order reflection or evaluation, proposed to be an essential element of consciousness. By contrast, the localist view argues that conscious content is linked to localized activations in content-specific cortical areas with no privileged role assigned to the prefrontal cortex in conscious experience in general. According to the localist view, just as posterior cortical areas underlie the conscious experience of visual perceptions, so does the prefrontal cortex underlie the conscious experience of specific categories of conscious contents such as reporting, thinking, speech, and introspection. Here I will review experimental evidence derived from human imaging and recordings, cortical lesions, and direct electrical stimulation in awake patients. Findings from these
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Dupont, P., G. A. Orban, R. Vogels, G. Bormans, J. Nuyts, C. Schiepers, M. De Roo, and L. Mortelmans. "Different perceptual tasks performed with the same visual stimulus attribute activate different regions of the human brain: a positron emission tomography study." Proceedings of the National Academy of Sciences 90, no. 23 (December 1, 1993): 10927–31. http://dx.doi.org/10.1073/pnas.90.23.10927.
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To investigate the processing of visual form in human cerebral cortex, we used the PET (positron emission tomography) activation technique to compare the human brain regions that are involved in a visual detection task and two orientation discrimination tasks: the temporal same-different (TSD) task, which includes a short-term memory component, and the identification (ID) task, which is without this component. As a control task we used passive viewing. Stimuli were identical in all four tasks. Subtraction of passive viewing from detection showed that the detection task activates early visual cortical regions (areas 17/18) as well as several motor brain regions, while decreasing activity in several higher order frontal, temporal, and parietal regions. Comparing the ID task to the detection task revealed no further visual cortical activation, while comparison of the TSD task to the detection task revealed an activation of several right visual cortical regions, one of which remained significant after the subtraction of ID from TSD (right area 19). These experiments demonstrate the task dependence of visual processing, even for very closely related tasks, and the localization of the temporal comparison component involved in orientation discrimination in human area 19.
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Rajimehr, Reza, Natalia Y. Bilenko, Wim Vanduffel, and Roger B. H. Tootell. "Retinotopy versus Face Selectivity in Macaque Visual Cortex." Journal of Cognitive Neuroscience 26, no. 12 (December 2014): 2691–700. http://dx.doi.org/10.1162/jocn_a_00672.
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Retinotopic organization is a ubiquitous property of lower-tier visual cortical areas in human and nonhuman primates. In macaque visual cortex, the retinotopic maps extend to higher-order areas in the ventral visual pathway, including area TEO in the inferior temporal (IT) cortex. Distinct regions within IT cortex are also selective to specific object categories such as faces. Here we tested the topographic relationship between retinotopic maps and face-selective patches in macaque visual cortex using high-resolution fMRI and retinotopic face stimuli. Distinct subregions within face-selective patches showed either (1) a coarse retinotopic map of eccentricity and polar angle, (2) a retinotopic bias to a specific location of visual field, or (3) nonretinotopic selectivity. In general, regions along the lateral convexity of IT cortex showed more overlap between retinotopic maps and face selectivity, compared with regions within the STS. Thus, face patches in macaques can be subdivided into smaller patches with distinguishable retinotopic properties.
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LEVENTHAL, AUDIE G., YONGCHANG WANG, MATTHEW T. SCHMOLESKY, and YIFENG ZHOU. "Neural correlates of boundary perception." Visual Neuroscience 15, no. 6 (November 1998): 1107–18. http://dx.doi.org/10.1017/s0952523898156110.
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The responses of neurons in areas V1 (17) and V2 (18) of anesthetized and paralyzed rhesus monkeys and cats were recorded while presenting a set of computer-generated visual stimuli that varied in pattern, texture, luminance, and contrast. We find that a class of extrastriate cortical cells in cats and monkeys can signal the presence of boundaries regardless of the cue or cues that define the boundaries. These cue-invariant (CI) cells were rare in area V1 but easily found in V2. CI cortical cells responded more strongly to more salient boundaries regardless of the cue defining the boundaries. Many CI cortical cells responded to illusory contours and exhibited the same degree of orientation and direction selectivity when tested with boundaries defined by different cues. These cells have significant computational power inherent in their receptive fields since they were able to generalize across stimuli and integrate multiple cues simultaneously in order to signal boundaries. Cells in higher order cortical areas such as MT (Albright, 1992), MST (Geesaman & Anderson, 1996), and IT (Sary et al., 1993) have previously been reported to respond in a cue invariant fashion. The present results suggest that the ability to respond to boundaries in a cue-invariant manner originates at relatively early stages of cortical processing.
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Lee, Charles C., and S. Murray Sherman. "Synaptic Properties of Thalamic and Intracortical Inputs to Layer 4 of the First- and Higher-Order Cortical Areas in the Auditory and Somatosensory Systems." Journal of Neurophysiology 100, no. 1 (July 2008): 317–26. http://dx.doi.org/10.1152/jn.90391.2008.
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The thalamus is an essential structure in the mammalian forebrain conveying information topographically from the sensory periphery to primary neocortical areas. Beyond this initial processing stage, “higher-order” thalamocortical connections have been presumed to serve only a modulatory role, or are otherwise functionally disregarded. Here we demonstrate that these “higher-order” thalamic nuclei share similar synaptic properties with the “first-order” thalamic nuclei. Using whole cell recordings from layer 4 neurons in thalamocortical slice preparations in the mouse somatosensory and auditory systems, we found that electrical stimulation in all thalamic nuclei elicited large, glutamatergic excitatory postsynaptic potentials (EPSPs) that depress in response to repetitive stimulation and that fail to activate a metabotropic glutamate response. In contrast, the intracortical inputs from layer 6 to layer 4 exhibit facilitating EPSPs. These data suggest that higher-order thalamocortical projections may serve a functional role similar to the first-order nuclei, whereas both are physiologically distinct from the intracortical layer 6 inputs. These results suggest an alternate route for information transfer between cortical areas via a corticothalamocortical pathway.
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Mendola, J. D., I. P. Conner, S. Sharma, A. Bahekar, and S. Lemieux. "fMRI Measures of Perceptual Filling-in in the Human Visual Cortex." Journal of Cognitive Neuroscience 18, no. 3 (March 1, 2006): 363–75. http://dx.doi.org/10.1162/jocn.2006.18.3.363.
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Filling-in refers to the tendency of stabilized retinal stimuli to fade and become replaced by their background. This phenomenon is a good example of central brain mechanisms that can selectively add or delete information to/from the retinal input. Importantly, such cortical mechanisms may overlap with those that are used more generally in visual perception. In order to identify cortical areas that contribute to perceptual filling-in, we used functional magnetic resonance imaging to image activity in the visual cortex while subjects experienced filling-in. Nine subjects viewed an achromatic disc with slightly higher luminance than the background and indicated the presence or absence of filling-in by a keypress. The disc was placed in either the upper or lower left quadrant. Similar high-contrast stimuli were used to map out the retinotopic representation of the disc. Unexpectedly, the lower-field high-contrast stimulus produced more parietal cortex activation than the upper-field condition, indicating preferential representation of the lower field by attentional control mechanisms. During perceptual filling-in, we observed significant contralateral reductions in activation in lower-tier retinotopic areas V1 and V2. In contrast, increased activation was consistently observed in visual areas V3A and V4v, higher-level cortex in the intraparietal sulcus, posterior superior temporal sulcus, and the ventral occipital–temporal region, as well as the pulvinar. The filling-in activation pattern was remarkably similar for both the upper- and lower-field conditions. Behaviorally, filling-in was reported to be easier for the lower visual field, and filling-in periods were longer for the lower than the upper quadrant. We suggest this behavioral asymmetry may be partially due to the preferential parietal representation of the lower field. The results lead us to propose that perceptual filling-in recruits high-level control mechanisms to reconcile competing percepts, and alters the normal image-related signals at the first stages of cortical processing. Moreover, the overall pattern of activation during filling-in resembles that seen in other studies of perceptually bistable stimuli, including binocular rivalry, indicating common control mechanisms.
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Ma, Li, Wentai Liu, and Andrew E. Hudson. "Propofol Anesthesia Increases Long-range Frontoparietal Corticocortical Interaction in the Oculomotor Circuit in Macaque Monkeys." Anesthesiology 130, no. 4 (April 1, 2019): 560–71. http://dx.doi.org/10.1097/aln.0000000000002637.
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Abstract Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New Background Frontoparietal functional connectivity decreases with multiple anesthetics using electrophysiology and functional imaging. This decrease has been proposed as a final common functional pathway to produce anesthesia. Two alternative measures of long-range cortical interaction are coherence and phase-amplitude coupling. Although phase-amplitude coupling within frontal cortex changes with propofol administration, the effects of propofol on phase-amplitude coupling between different cortical areas have not previously been reported. Based on phase-amplitude coupling observed within frontal lobe during the anesthetized period, it was hypothesized that between-lead phase-amplitude coupling analysis should decrease between frontal and parietal leads during propofol anesthesia. Methods A published monkey electrocorticography data set (N = 2 animals) was used to test for interactions in the cortical oculomotor circuit, which is robustly interconnected in primates, and in the visual system during propofol anesthesia using coherence and interarea phase-amplitude coupling. Results Propofol induces coherent slow oscillations in visual and oculomotor networks made up of cortical areas with strong anatomic projections. Frontal eye field within-area phase-amplitude coupling increases with a time course consistent with a bolus response to intravenous propofol (modulation index increase of 12.6-fold). Contrary to the hypothesis, interareal phase-amplitude coupling also increases with propofol, with the largest increase in phase-amplitude coupling in frontal eye field low-frequency phase modulating lateral intraparietal area β-power (27-fold increase) and visual area 2 low-frequency phase altering visual area 1 β-power (19-fold increase). Conclusions Propofol anesthesia induces coherent oscillations and increases certain frontoparietal interactions in oculomotor cortices. Frontal eye field and lateral intraparietal area show increased coherence and phase-amplitude coupling. Visual areas 2 and 1, which have similar anatomic projection patterns, show similar increases in phase-amplitude coupling, suggesting higher order feedback increases in influence during propofol anesthesia relative to wakefulness. This suggests that functional connectivity between frontal and parietal areas is not uniformly decreased by anesthetics.
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Hoshino, Osamu. "Neuronal Responses Below Firing Threshold for Subthreshold Cross-Modal Enhancement." Neural Computation 23, no. 4 (April 2011): 958–83. http://dx.doi.org/10.1162/neco_a_00096.
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Multisensory integration (such as somatosensation-vision, gustation-olfaction) could occur even between subthreshold stimuli that in isolation do not reach perceptual awareness. For example, when a somatosensory (subthreshold) stimulus is delivered within a close spatiotemporal congruency, a visual (subthreshold) stimulus evokes a visual percept. Cross-modal enhancement of visual perception is maximal when the somatosensory stimulation precedes the visual one by tens of milliseconds. This rapid modulatory response would not be consistent with a top-down mechanism acting through higher-order multimodal cortical areas, but rather a direct interaction between lower-order unimodal areas. To elucidate the neuronal mechanisms of subthreshold cross-modal enhancement, we simulated a neural network model. In the model, lower unimodal (X, Y) and higher multimodal (M) networks are reciprocally connected by bottom-up and top-down axonal projections. The lower networks are laterally connected with each other. A pair of stimuli was presented to the lower networks, whose respective intensities were too weak to induce salient neuronal activity (population response) when presented alone. Neurons of the Y network were slightly depolarized below firing threshold when a cross-modal stimulus was presented alone to the X network. This allowed the Y network to make a rapid (within tens of milliseconds) population response when presented with a subsequent congruent stimulus. The reaction speed of the Y network was accelerated, provided that the top-down projections were strengthened. We suggest that a subthreshold (nonpopulation) response to a cross-modal stimulus, acting through interaction between lower (primary unisensory) areas, may be essential for a rapid suprathreshold (population) response to a congruent stimulus that follows. Top-down influences on cross-modal enhancement may be faster than expected, accelerating reaction speed to input, in which ongoing-spontaneous subthreshold excitation of lower-order unimodal cells by higher-order multimodal cells may play an active role.
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Binetti, Nicola, Alessandro Tomassini, Karl Friston, and Sven Bestmann. "Uncoupling Sensation and Perception in Human Time Processing." Journal of Cognitive Neuroscience 32, no. 7 (July 2020): 1369–80. http://dx.doi.org/10.1162/jocn_a_01557.
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Timing emerges from a hierarchy of computations ranging from early encoding of physical duration (time sensation) to abstract time representations (time perception) suitable for storage and decisional processes. However, the neural basis of the perceptual experience of time remains elusive. To address this, we dissociate brain activity uniquely related to lower-level sensory and higher-order perceptual timing operations, using event-related fMRI. Participants compared subsecond (500 msec) sinusoidal gratings drifting with constant velocity (standard) against two probe stimuli: (1) control gratings drifting at constant velocity or (2) accelerating gratings, which induced illusory shortening of time. We tested two probe intervals: a 500-msec duration (Short) and a longer duration required for an accelerating probe to be perceived as long as the standard (Long—individually determined). On each trial, participants classified the probe as shorter or longer than the standard. This allowed for comparison of trials with an “Objective” (physical) or “Subjective” (perceived) difference in duration, based on participant classifications. Objective duration revealed responses in bilateral early extrastriate areas, extending to higher visual areas in the fusiform gyrus (at more lenient thresholds). By contrast, Subjective duration was reflected by distributed responses in a cortical/subcortical areas. This comprised the left superior frontal gyrus and the left cerebellum, and a wider set of common timing areas including the BG, parietal cortex, and posterior cingulate cortex. These results suggest two functionally independent timing stages: early extraction of duration information in sensory cortices and Subjective experience of duration in a higher-order cortical–subcortical timing areas.
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Bekhtereva, Valeria, Matt Craddock, and Matthias M. Müller. "Affective Bias without Hemispheric Competition: Evidence for Independent Processing Resources in Each Cortical Hemisphere." Journal of Cognitive Neuroscience 32, no. 5 (May 2020): 963–76. http://dx.doi.org/10.1162/jocn_a_01526.
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We assessed the extent of neural competition for attentional processing resources in early visual cortex between foveally presented task stimuli and peripheral emotional distracter images. Task-relevant and distracting stimuli were shown in rapid serial visual presentation (RSVP) streams to elicit the steady-state visual evoked potential, which serves as an electrophysiological marker of attentional resource allocation in early visual cortex. A task-related RSVP stream of symbolic letters was presented centrally at 15 Hz while distracting RSVP streams were displayed at 4 or 6 Hz in the left and right visual hemifields. These image streams always had neutral content in one visual field and would unpredictably switch from neutral to unpleasant content in the opposite visual field. We found that the steady-state visual evoked potential amplitude was consistently modulated as a function of change in emotional valence in peripheral RSVPs, indicating sensory gain in response to distracting affective content. Importantly, the facilitated processing for emotional content shown in one visual hemifield was not paralleled by any perceptual costs in response to the task-related processing in the center or the neutral image stream in the other visual hemifield. Together, our data provide further evidence for sustained sensory facilitation in favor of emotional distracters. Furthermore, these results are in line with previous reports of a “different hemifield advantage” with low-level visual stimuli and are suggestive of independent processing resources in each cortical hemisphere that operate beyond low-level visual cues, that is, with complex images that impact early stages of visual processing via reentrant feedback loops from higher order processing areas.
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Minakaran, Neda, Talha Soorma, Adolfo M. Bronstein, and Gordon T. Plant. "Charles Bonnet syndrome and periodic alternating nystagmus." Neurology 92, no. 10 (January 30, 2019): e1072-e1075. http://dx.doi.org/10.1212/wnl.0000000000007033.
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ObjectiveTo describe and discuss potential mechanisms for modulation of visual hallucinations by nystagmus.MethodsWe present 2 patients with coexistent Charles Bonnet syndrome and periodic alternating nystagmus in the context of acquired visual loss.ResultsThe combination has given rise to a rare phenomenon: visual hallucinations that move in a manner governed by the nystagmus, specifically by the direction and velocity of the slow phase. The perceived modulation of movement is selective for a surface in one case and a landscape in the other but not present for hallucinated individual objects and people separate from the hallucinated background visual scene.ConclusionsThe collision of Charles Bonnet syndrome and periodic alternating nystagmus in these 2 patients has demonstrated that some visual hallucinations can be modulated by, or collaterally with, ocular movements. We propose 2 potential mechanisms based on ocular proprioceptive input from extraocular muscles projecting to either extrastriate processing of visual scene, or to higher-order visual cortical areas involved in analysis of motion signals across the whole visual field.
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Hass, Charles A., and Lindsey L. Glickfeld. "High-fidelity optical excitation of cortico-cortical projections at physiological frequencies." Journal of Neurophysiology 116, no. 5 (November 1, 2016): 2056–66. http://dx.doi.org/10.1152/jn.00456.2016.
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Optogenetic activation of axons is a powerful approach for determining the synaptic properties and impact of long-range projections both in vivo and in vitro. However, because of the difficulty of measuring activity in axons, our knowledge of the reliability of optogenetic axonal stimulation has relied on data from somatic recordings. Yet, there are many reasons why activation of axons may not be comparable to cell bodies. Thus we have developed an approach to more directly assess the fidelity of optogenetic activation of axonal projections. We expressed opsins (ChR2, Chronos, or oChIEF) in the mouse primary visual cortex (V1) and recorded extracellular, pharmacologically isolated presynaptic action potentials in response to axonal activation in the higher visual areas. Repetitive stimulation of axons with ChR2 resulted in a 70% reduction in the fiber volley amplitude and a 60% increase in the latency at all frequencies tested (10–40 Hz). Thus ChR2 cannot reliably recruit axons during repetitive stimulation, even at frequencies that are reliable for somatic stimulation, likely due to pronounced channel inactivation at the high light powers required to evoke action potentials. By comparison, oChIEF and Chronos evoked photocurrents that inactivated minimally and could produce reliable axon stimulation at frequencies up to 60 Hz. Our approach provides a more direct and accurate evaluation of the efficacy of new optogenetic tools and has identified Chronos and oChIEF as viable tools to interrogate the synaptic and circuit function of long-range projections.
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Panagiotaropoulos, Theofanis I., Vishal Kapoor, and Nikos K. Logothetis. "Subjective visual perception: from local processing to emergent phenomena of brain activity." Philosophical Transactions of the Royal Society B: Biological Sciences 369, no. 1641 (May 5, 2014): 20130534. http://dx.doi.org/10.1098/rstb.2013.0534.
Full textAbstract:
The combination of electrophysiological recordings with ambiguous visual stimulation made possible the detection of neurons that represent the content of subjective visual perception and perceptual suppression in multiple cortical and subcortical brain regions. These neuronal populations, commonly referred to as the neural correlates of consciousness , are more likely to be found in the temporal and prefrontal cortices as well as the pulvinar, indicating that the content of perceptual awareness is represented with higher fidelity in higher-order association areas of the cortical and thalamic hierarchy, reflecting the outcome of competitive interactions between conflicting sensory information resolved in earlier stages. However, despite the significant insights into conscious perception gained through monitoring the activities of single neurons and small, local populations, the immense functional complexity of the brain arising from correlations in the activity of its constituent parts suggests that local, microscopic activity could only partially reveal the mechanisms involved in perceptual awareness. Rather, the dynamics of functional connectivity patterns on a mesoscopic and macroscopic level could be critical for conscious perception. Understanding these emergent spatio-temporal patterns could be informative not only for the stability of subjective perception but also for spontaneous perceptual transitions suggested to depend either on the dynamics of antagonistic ensembles or on global intrinsic activity fluctuations that may act upon explicit neural representations of sensory stimuli and induce perceptual reorganization. Here, we review the most recent results from local activity recordings and discuss the potential role of effective, correlated interactions during perceptual awareness.
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Parra, Andres, Christopher A. Baker, and M. McLean Bolton. "Regional Specialization of Pyramidal Neuron Morphology and Physiology in the Tree Shrew Neocortex." Cerebral Cortex 29, no. 11 (January 31, 2019): 4488–505. http://dx.doi.org/10.1093/cercor/bhy326.
Full textAbstract:
Abstract The mammalian cerebral cortex is divided into different areas according to their function and pattern of connections. Studies comparing primary visual (V1) and prefrontal cortex (PFC) of primates have demonstrated striking pyramidal neuron (PN) specialization not present in comparable areas of the mouse neocortex. To better understand PFC evolution and regional PN specialization, we studied the tree shrew, a species with a close phylogenetic relationship to primates. We defined the tree shrew PFC based on cytoarchitectonic borders, thalamic connectivity and characterized the morphology and electrophysiology of layer II/III PNs in V1 and PFC. Similar to primates, the PFC PNs in the tree shrew fire with a regular spiking pattern and have larger dendritic tree and spines than those in V1. However, V1 PNs showed strikingly large basal dendritic arbors with high spine density, firing at higher rates and in a more varied pattern than PFC PNs. Yet, unlike in the mouse and unreported in the primate, medial prefrontal PN are more easily recruited than either the dorsolateral or V1 neurons. This specialization of PN morphology and physiology is likely to be a significant factor in the evolution of cortex, contributing to differences in the computational capacities of individual cortical areas.
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ANTAL, A., J. BAUDEWIG, W. PAULUS, and P. DECHENT. "The posterior cingulate cortex and planum temporale/parietal operculum are activated by coherent visual motion." Visual Neuroscience 25, no. 1 (January 2008): 17–26. http://dx.doi.org/10.1017/s0952523808080024.
Full textAbstract:
The posterior cingulate cortex (PCC) is involved in higher order sensory and sensory-motor integration while the planum temporale/parietal operculum (PT/PO) junction takes part in auditory motion and vestibular processing. Both regions are activated during different types of visual stimulation. Here, we describe the response characteristics of the PCC and PT/PO to basic types of visual motion stimuli of different complexity (complex and simple coherent as well as incoherent motion). Functional magnetic resonance imaging (fMRI) was performed in 10 healthy subjects at 3 Tesla, whereby different moving dot stimuli (vertical, horizontal, rotational, radial, and random) were contrasted against a static dot pattern. All motion stimuli activated a distributed cortical network, including previously described motion-sensitive striate and extrastriate visual areas. Bilateral activations in the dorsal region of the PCC (dPCC) were evoked using coherent motion stimuli, irrespective of motion direction (vertical, horizontal, rotational, radial) with increasing activity and with higher complexity of the stimulus. In contrast, the PT/PO responded equally well to all of the different coherent motion types. Incoherent (random) motion yielded significantly less activation both in the dPCC and in the PT/PO area. These results suggest that the dPCC and the PT/PO take part in the processing of basic types of visual motion. However, in dPCC a possible effect of attentional modulation resulting in the higher activity evoked by the complex stimuli should also be considered. Further studies are warranted to incorporate these regions into the current model of the cortical motion processing network.
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Kita, Yoshiaki, Hirozumi Nishibe, Yan Wang, Tsutomu Hashikawa, Satomi S. Kikuchi, Mami U, Aya C. Yoshida, et al. "Cellular-resolution gene expression profiling in the neonatal marmoset brain reveals dynamic species- and region-specific differences." Proceedings of the National Academy of Sciences 118, no. 18 (April 26, 2021): e2020125118. http://dx.doi.org/10.1073/pnas.2020125118.
Full textAbstract:
Precise spatiotemporal control of gene expression in the developing brain is critical for neural circuit formation, and comprehensive expression mapping in the developing primate brain is crucial to understand brain function in health and disease. Here, we developed an unbiased, automated, large-scale, cellular-resolution in situ hybridization (ISH)–based gene expression profiling system (GePS) and companion analysis to reveal gene expression patterns in the neonatal New World marmoset cortex, thalamus, and striatum that are distinct from those in mice. Gene-ontology analysis of marmoset-specific genes revealed associations with catalytic activity in the visual cortex and neuropsychiatric disorders in the thalamus. Cortically expressed genes with clear area boundaries were used in a three-dimensional cortical surface mapping algorithm to delineate higher-order cortical areas not evident in two-dimensional ISH data. GePS provides a powerful platform to elucidate the molecular mechanisms underlying primate neurobiology and developmental psychiatric and neurological disorders.