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Teymornejad S, Worthy KH, Rosa MGP, Atapour N. Giant pyramidal neurons of the primary motor cortex express vasoactive intestinal polypeptide (VIP), a known marker of cortical interneurons. Sci Rep 2024; 14:21174. [PMID: 39256434 DOI: 10.1038/s41598-024-71637-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 08/29/2024] [Indexed: 09/12/2024] Open
Abstract
Vasoactive intestinal polypeptide (VIP) is known to be present in a subclass of cortical interneurons. Here, using three different antibodies, we demonstrate that VIP is also present in the giant layer 5 pyramidal (Betz) neurons which are characteristic of the limb and axial representations of the marmoset primary motor cortex (cytoarchitectural area 4ab). No VIP staining was observed in smaller layer 5 pyramidal cells present in the primary motor facial representation (cytoarchitectural area 4c), or in the premotor cortex (e.g. the caudal subdivision of the dorsal premotor cortex, A6DC), indicating the selective expression of VIP in Betz cells. VIP in Betz cells was colocalized with neuronal specific marker (NeuN) and a calcium-binding protein parvalbumin (PV). PV also intensely labelled axon terminals surrounding Betz cell somata. VIP-positive interneurons were more abundant in the superficial cortical layers and constituted about 5-7% of total cortical neurons, with the highest density observed in area 4c. Our results demonstrate the expression of VIP in the largest excitatory neurons of the primate cortex, which may offer new functional insights into the role of VIP in the brain, and provide opportunities for genetic manipulation of Betz cells.
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Affiliation(s)
- Sadaf Teymornejad
- Department of Physiology and Neuroscience Program, Biomedicine Discovery Institute, Monash University, Clayton, Melbourne, VIC, 3800, Australia
| | - Katrina H Worthy
- Department of Physiology and Neuroscience Program, Biomedicine Discovery Institute, Monash University, Clayton, Melbourne, VIC, 3800, Australia
| | - Marcello G P Rosa
- Department of Physiology and Neuroscience Program, Biomedicine Discovery Institute, Monash University, Clayton, Melbourne, VIC, 3800, Australia
| | - Nafiseh Atapour
- Department of Physiology and Neuroscience Program, Biomedicine Discovery Institute, Monash University, Clayton, Melbourne, VIC, 3800, Australia.
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2
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Intoy J, Li YH, Bowers NR, Victor JD, Poletti M, Rucci M. Consequences of eye movements for spatial selectivity. Curr Biol 2024; 34:3265-3272.e4. [PMID: 38981478 PMCID: PMC11348862 DOI: 10.1016/j.cub.2024.06.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 05/17/2024] [Accepted: 06/07/2024] [Indexed: 07/11/2024]
Abstract
What determines spatial tuning in the visual system? Standard views rely on the assumption that spatial information is directly inherited from the relative position of photoreceptors and shaped by neuronal connectivity.1,2 However, human eyes are always in motion during fixation,3,4,5,6 so retinal neurons receive temporal modulations that depend on the interaction of the spatial structure of the stimulus with eye movements. It has long been hypothesized that these modulations might contribute to spatial encoding,7,8,9,10,11,12 a proposal supported by several recent observations.13,14,15,16 A fundamental, yet untested, consequence of this encoding strategy is that spatial tuning is not hard-wired in the visual system but critically depends on how the fixational motion of the eye shapes the temporal structure of the signals impinging onto the retina. Here we used high-resolution techniques for eye-tracking17 and gaze-contingent display control18 to quantitatively test this distinctive prediction. We examined how contrast sensitivity, a hallmark of spatial vision, is influenced by fixational motion, both during normal active fixation and when the spatiotemporal stimulus on the retina is altered to mimic changes in fixational control. We showed that visual sensitivity closely follows the strength of the luminance modulations delivered within a narrow temporal bandwidth, so changes in fixational motion have opposite visual effects at low and high spatial frequencies. By identifying a key role for oculomotor activity in spatial selectivity, these findings have important implications for the perceptual consequences of abnormal eye movements, the sources of perceptual variability, and the function of oculomotor control.
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Affiliation(s)
- Janis Intoy
- Center for Visual Science, University of Rochester, Rochester, NY, USA; Department of Brain and Cognitive Sciences, University of Rochester, Rochester, NY, USA
| | - Yuanhao H Li
- Center for Visual Science, University of Rochester, Rochester, NY, USA; Department of Brain and Cognitive Sciences, University of Rochester, Rochester, NY, USA
| | - Norick R Bowers
- Department of Psychology, Justus-Liebig University, Giessen, Germany
| | - Jonathan D Victor
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York City, NY, USA
| | - Martina Poletti
- Center for Visual Science, University of Rochester, Rochester, NY, USA; Department of Brain and Cognitive Sciences, University of Rochester, Rochester, NY, USA
| | - Michele Rucci
- Center for Visual Science, University of Rochester, Rochester, NY, USA; Department of Brain and Cognitive Sciences, University of Rochester, Rochester, NY, USA.
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3
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Fleming LL, Defenderfer M, Demirayak P, Stewart P, Decarlo DK, Visscher KM. Impact of deprivation and preferential usage on functional connectivity between early visual cortex and category selective visual regions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.17.593020. [PMID: 38798355 PMCID: PMC11118586 DOI: 10.1101/2024.05.17.593020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Human behavior can be remarkably shaped by experience, such as the removal of sensory input. Many studies of conditions such as stroke, limb amputation, and vision loss have examined how the removal of input changes brain function. However, an important question has yet to be answered: when input is lost, does the brain change its connectivity to preferentially use some remaining inputs over others? In individuals with healthy vision, the central portion of the retina is preferentially used for everyday visual tasks, due to its ability to discriminate fine details. However, when central vision is lost in conditions like macular degeneration, peripheral vision must be relied upon for those everyday tasks, with certain portions receiving "preferential" usage over others. Using resting-state fMRI collected during total darkness, we examined how deprivation and preferential usage influence the intrinsic functional connectivity of sensory cortex by studying individuals with selective vision loss due to late stages of macular degeneration. We found that cortical regions representing spared portions of the peripheral retina, regardless of whether they are preferentially used, exhibit plasticity of intrinsic functional connectivity in macular degeneration. Cortical representations of spared peripheral retinal locations showed stronger connectivity to MT, a region involved in processing motion. These results suggest that long-term loss of central vision can produce widespread effects throughout spared representations in early visual cortex, regardless of whether those representations are preferentially used. These findings support the idea that connections to visual cortex maintain the capacity for change well after critical periods of visual development. Highlights Portions of early visual cortex representing central vs. peripheral vision exhibit different patterns of connectivity to category-selective visual regions.When central vision is lost, cortical representations of peripheral vision display stronger functional connections to MT than central representations.When central vision is lost, connectivity to regions selective for tasks that involve central vision (FFA and PHA) are not significantly altered.These effects do not depend on which locations of peripheral vision are used more.
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4
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da Costa D, Kornemann L, Goebel R, Senden M. Convolutional neural networks develop major organizational principles of early visual cortex when enhanced with retinal sampling. Sci Rep 2024; 14:8980. [PMID: 38637554 PMCID: PMC11026486 DOI: 10.1038/s41598-024-59376-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 04/09/2024] [Indexed: 04/20/2024] Open
Abstract
Primate visual cortex exhibits key organizational principles: cortical magnification, eccentricity-dependent receptive field size and spatial frequency tuning as well as radial bias. We provide compelling evidence that these principles arise from the interplay of the non-uniform distribution of retinal ganglion cells, and a quasi-uniform convergence rate from the retina to the cortex. We show that convolutional neural networks outfitted with a retinal sampling layer, which resamples images according to retinal ganglion cell density, develop these organizational principles. Surprisingly, our results indicate that radial bias is spatial-frequency dependent and only manifests for high spatial frequencies. For low spatial frequencies, the bias shifts towards orthogonal orientations. These findings introduce a novel hypothesis about the origin of radial bias. Quasi-uniform convergence limits the range of spatial frequencies (in retinal space) that can be resolved, while retinal sampling determines the spatial frequency content throughout the retina.
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Affiliation(s)
- Danny da Costa
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Oxfordlaan 55, 6229 EV, Maastricht, The Netherlands.
- Maastricht Brain Imaging Centre, Maastricht University, Oxfordlaan 55, 6229 EV, Maastricht, The Netherlands.
| | - Lukas Kornemann
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Oxfordlaan 55, 6229 EV, Maastricht, The Netherlands
- University of Bonn, Regina-Pacis-Weg 3, 53113, Bonn, Germany
| | - Rainer Goebel
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Oxfordlaan 55, 6229 EV, Maastricht, The Netherlands
- Maastricht Brain Imaging Centre, Maastricht University, Oxfordlaan 55, 6229 EV, Maastricht, The Netherlands
| | - Mario Senden
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Oxfordlaan 55, 6229 EV, Maastricht, The Netherlands.
- Maastricht Brain Imaging Centre, Maastricht University, Oxfordlaan 55, 6229 EV, Maastricht, The Netherlands.
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5
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Samonds JM, Szinte M, Barr C, Montagnini A, Masson GS, Priebe NJ. Mammals Achieve Common Neural Coverage of Visual Scenes Using Distinct Sampling Behaviors. eNeuro 2024; 11:ENEURO.0287-23.2023. [PMID: 38164577 PMCID: PMC10860624 DOI: 10.1523/eneuro.0287-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 10/24/2023] [Accepted: 10/30/2023] [Indexed: 01/03/2024] Open
Abstract
Most vertebrates use head and eye movements to quickly change gaze orientation and sample different portions of the environment with periods of stable fixation. Visual information must be integrated across fixations to construct a complete perspective of the visual environment. In concert with this sampling strategy, neurons adapt to unchanging input to conserve energy and ensure that only novel information from each fixation is processed. We demonstrate how adaptation recovery times and saccade properties interact and thus shape spatiotemporal tradeoffs observed in the motor and visual systems of mice, cats, marmosets, macaques, and humans. These tradeoffs predict that in order to achieve similar visual coverage over time, animals with smaller receptive field sizes require faster saccade rates. Indeed, we find comparable sampling of the visual environment by neuronal populations across mammals when integrating measurements of saccadic behavior with receptive field sizes and V1 neuronal density. We propose that these mammals share a common statistically driven strategy of maintaining coverage of their visual environment over time calibrated to their respective visual system characteristics.
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Affiliation(s)
- Jason M Samonds
- Center for Learning and Memory and the Institute for Neuroscience, The University of Texas at Austin, Austin 78712, Texas
| | - Martin Szinte
- Institut de Neurosciences de la Timone (UMR 7289), Centre National de la Recherche Scientifique and Aix-Marseille Université, 13385 Marseille, France
| | - Carrie Barr
- Center for Learning and Memory and the Institute for Neuroscience, The University of Texas at Austin, Austin 78712, Texas
| | - Anna Montagnini
- Institut de Neurosciences de la Timone (UMR 7289), Centre National de la Recherche Scientifique and Aix-Marseille Université, 13385 Marseille, France
| | - Guillaume S Masson
- Institut de Neurosciences de la Timone (UMR 7289), Centre National de la Recherche Scientifique and Aix-Marseille Université, 13385 Marseille, France
| | - Nicholas J Priebe
- Center for Learning and Memory and the Institute for Neuroscience, The University of Texas at Austin, Austin 78712, Texas
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6
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DeCouto BS, Fawver B, Thomas JL, Williams AM, Vater C. The role of peripheral vision during decision-making in dynamic viewing sequences. J Sports Sci 2023; 41:1852-1867. [PMID: 38234241 DOI: 10.1080/02640414.2023.2301143] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 12/21/2023] [Indexed: 01/19/2024]
Abstract
Decision-making in team sports necessitates monitoring multiple performers located at different distances (i.e., viewing eccentricities) from a critical information source. The processing of peripheral information is generally impaired under anxiety and when responding to stimuli located at larger eccentricities. These hypotheses have not been sufficiently tested in dynamic performance environments. We examined how pressure and eccentricities affect decision-making and visual behaviour in 4v4 basketball defensive scenarios using a head mounted display. Experienced players monitored plays from the first-person perspective (centre position) and made defensive steps towards opponents threatening the basket from different eccentricities under low- and high-pressure. To tax working memory, participants simultaneously performed a backward counting task. Players responded slower and with lower accuracy to opponents at larger eccentricities. Players mostly fixated on the ball-carrier, but over 50% of fixations were located on peripheral players, indicating that information in the periphery must be frequently updated with foveal vision (i.e., pivot strategy). When pressured, participants increased mental effort and improved counting performance; however, gaze behaviour and decision-making were relatively unaffected. Findings suggest that basketball players respond more quickly to opponents positioned at lower compared to higher eccentricities at the cost of impaired responses to opponents in the periphery.
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Affiliation(s)
- B S DeCouto
- Human Health, Resilience & Performance, Institute for Human and Machine Cognition, Pensacola, FL, USA
| | - B Fawver
- US Army Medical Research Directorate-West, Walter Reed Army Institute of Research, WA, Joint Base Lewis-McChord, USA
| | | | - A M Williams
- Human Health, Resilience & Performance, Institute for Human and Machine Cognition, Pensacola, FL, USA
| | - C Vater
- Department of Movement and Training, Institute of Sport Science, University of Bern, Bern, Switzerland
- Department of Humanities, Social and Political Sciences, Chair of Cognitive Science, ETH Zurich Chair of Cognitive Science, Zürich, Switzerland
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7
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Samonds JM, Szinte M, Barr C, Montagnini A, Masson GS, Priebe NJ. Mammals achieve common neural coverage of visual scenes using distinct sampling behaviors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.20.533210. [PMID: 36993477 PMCID: PMC10055212 DOI: 10.1101/2023.03.20.533210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Most vertebrates use head and eye movements to quickly change gaze orientation and sample different portions of the environment with periods of stable fixation. Visual information must be integrated across several fixations to construct a more complete perspective of the visual environment. In concert with this sampling strategy, neurons adapt to unchanging input to conserve energy and ensure that only novel information from each fixation is processed. We demonstrate how adaptation recovery times and saccade properties interact, and thus shape spatiotemporal tradeoffs observed in the motor and visual systems of different species. These tradeoffs predict that in order to achieve similar visual coverage over time, animals with smaller receptive field sizes require faster saccade rates. Indeed, we find comparable sampling of the visual environment by neuronal populations across mammals when integrating measurements of saccadic behavior with receptive field sizes and V1 neuronal density. We propose that these mammals share a common statistically driven strategy of maintaining coverage of their visual environment over time calibrated to their respective visual system characteristics.
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8
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Gaglianese A, Fracasso A, Fernandes FG, Harvey B, Dumoulin SO, Petridou N. Mechanisms of speed encoding in the human middle temporal cortex measured by 7T fMRI. Hum Brain Mapp 2023; 44:2050-2061. [PMID: 36637226 PMCID: PMC9980888 DOI: 10.1002/hbm.26193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 11/28/2022] [Accepted: 12/11/2022] [Indexed: 01/14/2023] Open
Abstract
Perception of dynamic scenes in our environment results from the evaluation of visual features such as the fundamental spatial and temporal frequency components of a moving object. The ratio between these two components represents the object's speed of motion. The human middle temporal cortex hMT+ has a crucial biological role in the direct encoding of object speed. However, the link between hMT+ speed encoding and the spatiotemporal frequency components of a moving object is still under explored. Here, we recorded high resolution 7T blood oxygen level-dependent BOLD responses to different visual motion stimuli as a function of their fundamental spatial and temporal frequency components. We fitted each hMT+ BOLD response with a 2D Gaussian model allowing for two different speed encoding mechanisms: (1) distinct and independent selectivity for the spatial and temporal frequencies of the visual motion stimuli; (2) pure tuning for the speed of motion. We show that both mechanisms occur but in different neuronal groups within hMT+, with the largest subregion of the complex showing separable tuning for the spatial and temporal frequency of the visual stimuli. Both mechanisms were highly reproducible within participants, reconciling single cell recordings from MT in animals that have showed both encoding mechanisms. Our findings confirm that a more complex process is involved in the perception of speed than initially thought and suggest that hMT+ plays a primary role in the evaluation of the spatial features of the moving visual input.
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Affiliation(s)
- Anna Gaglianese
- The Laboratory for Investigative Neurophysiology (The LINE), Department of RadiologyUniversity Hospital Center and University of LausanneLausanneSwitzerland
- Department of Neurosurgery and Neurology, UMC Utrecht Brain CenterUniversity Medical CenterUtrechtNetherlands
- Department of Radiology, Center for Image SciencesUniversity Medical CenterUtrechtNetherlands
| | - Alessio Fracasso
- Department of Radiology, Center for Image SciencesUniversity Medical CenterUtrechtNetherlands
- University of GlasgowSchool of Psychology and NeuroscienceGlasgowUK
- Spinoza Center for NeuroimagingAmsterdamNetherlands
| | - Francisco G. Fernandes
- Department of Neurosurgery and Neurology, UMC Utrecht Brain CenterUniversity Medical CenterUtrechtNetherlands
| | - Ben Harvey
- Experimental Psychology, Helmholtz InstituteUtrecht UniversityUtrechtNetherlands
| | - Serge O. Dumoulin
- Experimental Psychology, Helmholtz InstituteUtrecht UniversityUtrechtNetherlands
| | - Natalia Petridou
- Department of Radiology, Center for Image SciencesUniversity Medical CenterUtrechtNetherlands
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9
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Zhang Y, Schriver KE, Hu JM, Roe AW. Spatial frequency representation in V2 and V4 of macaque monkey. eLife 2023; 12:81794. [PMID: 36607323 PMCID: PMC9848390 DOI: 10.7554/elife.81794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 01/05/2023] [Indexed: 01/07/2023] Open
Abstract
Spatial frequency (SF) is an important attribute in the visual scene and is a defining feature of visual processing channels. However, there remain many unsolved questions about how extrastriate areas in primate visual cortex code this fundamental information. Here, using intrinsic signal optical imaging in visual areas of V2 and V4 of macaque monkeys, we quantify the relationship between SF maps and (1) visual topography and (2) color and orientation maps. We find that in orientation regions, low to high SF is mapped orthogonally to orientation; in color regions, which are reported to contain orthogonal axes of color and lightness, low SFs tend to be represented more frequently than high SFs. This supports a population-based SF fluctuation related to the 'color/orientation' organizations. We propose a generalized hypercolumn model across cortical areas, comprised of two orthogonal parameters with additional parameters.
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Affiliation(s)
- Ying Zhang
- Department of Neurosurgery of the Second Affiliated Hospital, Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang UniversityHangzhouChina
- Key Laboratory of Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang UniversityHangzhouChina
| | - Kenneth E Schriver
- Department of Neurosurgery of the Second Affiliated Hospital, Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang UniversityHangzhouChina
- Key Laboratory of Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang UniversityHangzhouChina
- MOE Frontier Science Center for Brain Science and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang UniversityHangzhouChina
| | - Jia Ming Hu
- Department of Neurosurgery of the Second Affiliated Hospital, Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang UniversityHangzhouChina
- Key Laboratory of Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang UniversityHangzhouChina
- MOE Frontier Science Center for Brain Science and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang UniversityHangzhouChina
| | - Anna Wang Roe
- Department of Neurosurgery of the Second Affiliated Hospital, Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang UniversityHangzhouChina
- Key Laboratory of Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang UniversityHangzhouChina
- MOE Frontier Science Center for Brain Science and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang UniversityHangzhouChina
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10
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Sedigh-Sarvestani M, Fitzpatrick D. What and Where: Location-Dependent Feature Sensitivity as a Canonical Organizing Principle of the Visual System. Front Neural Circuits 2022; 16:834876. [PMID: 35498372 PMCID: PMC9039279 DOI: 10.3389/fncir.2022.834876] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 03/01/2022] [Indexed: 11/13/2022] Open
Abstract
Traditionally, functional representations in early visual areas are conceived as retinotopic maps preserving ego-centric spatial location information while ensuring that other stimulus features are uniformly represented for all locations in space. Recent results challenge this framework of relatively independent encoding of location and features in the early visual system, emphasizing location-dependent feature sensitivities that reflect specialization of cortical circuits for different locations in visual space. Here we review the evidence for such location-specific encoding including: (1) systematic variation of functional properties within conventional retinotopic maps in the cortex; (2) novel periodic retinotopic transforms that dramatically illustrate the tight linkage of feature sensitivity, spatial location, and cortical circuitry; and (3) retinotopic biases in cortical areas, and groups of areas, that have been defined by their functional specializations. We propose that location-dependent feature sensitivity is a fundamental organizing principle of the visual system that achieves efficient representation of positional regularities in visual experience, and reflects the evolutionary selection of sensory and motor circuits to optimally represent behaviorally relevant information. Future studies are necessary to discover mechanisms underlying joint encoding of location and functional information, how this relates to behavior, emerges during development, and varies across species.
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11
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Visual Cortical Area MT Is Required for Development of the Dorsal Stream and Associated Visuomotor Behaviors. J Neurosci 2021; 41:8197-8209. [PMID: 34417331 DOI: 10.1523/jneurosci.0824-21.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 07/07/2021] [Accepted: 08/09/2021] [Indexed: 01/11/2023] Open
Abstract
The middle temporal (MT) area of the extrastriate visual cortex has long been studied in adulthood for its distinctive physiological properties and function as a part of the dorsal stream, yet interestingly it possesses a similar maturation profile as the primary visual cortex (V1). Here, we examined whether an early-life lesion in MT of marmoset monkeys (six female, two male) altered the dorsal stream development and the behavioral precision of reaching-to-grasp sequences. We observed permanent changes in the anatomy of cortices associated with both reaching (parietal and medial intraparietal areas) and grasping (anterior intraparietal area), as well as in reaching-and-grasping behaviors. In addition, we observed a significant impact on the anatomy of V1 and the direction sensitivity of V1 neurons in the lesion projection zone. These findings indicate that area MT is a crucial node in the development of primate vision, affecting both V1 and areas in the dorsal visual pathway known to mediate visually guided manual behaviors.SIGNIFICANCE STATEMENT Previous studies have identified a role for the MT area of the visual cortex in perceiving motion, yet none have examined its central role in the development of the visual cortex and in the establishment of visuomotor behaviors. To address this, we used a unilateral MT lesion model in neonatal marmosets before examining the anatomic, physiological, and behavioral consequences. In adulthood, we observed perturbations in goal-orientated reach-and-grasp behavior, altered direction selectivity of V1 neurons, and changes in the cytoarchitecture throughout dorsal stream areas. This study highlights the importance of MT as a central node in visual system development and consequential visuomotor activity.
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12
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Hagan MA, Chaplin TA, Huxlin KR, Rosa MGP, Lui LL. Altered Sensitivity to Motion of Area MT Neurons Following Long-Term V1 Lesions. Cereb Cortex 2021; 30:451-464. [PMID: 31211357 DOI: 10.1093/cercor/bhz096] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 04/16/2019] [Accepted: 04/16/2019] [Indexed: 02/04/2023] Open
Abstract
Primates with primary visual cortex (V1) damage often retain residual motion sensitivity, which is hypothesized to be mediated by middle temporal area (MT). MT neurons continue to respond to stimuli shortly after V1 lesions; however, experimental and clinical studies of lesion-induced plasticity have shown that lesion effects can take several months to stabilize. It is unknown what physiological changes occur in MT and whether neural responses persist long after V1 damage. We recorded neuronal responses in MT to moving dot patterns in adult marmoset monkeys 6-12 months after unilateral V1 lesions. In contrast to results obtained shortly after V1 lesions, we found that fewer MT neurons were direction selective, including neurons expected to still receive projections from remaining parts of V1. The firing rates of most cells increased with increases in motion strength, regardless of stimulus direction. Furthermore, firing rates were higher and more variable than in control MT cells. To test whether these observations could be mechanistically explained by underlying changes in neural circuitry, we created a network model of MT. We found that a local imbalance of inhibition and excitation explained the observed firing rate changes. These results provide the first insights into functional implications of long-term plasticity in MT following V1 lesions.
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Affiliation(s)
- Maureen A Hagan
- Department of Physiology, Monash University, Clayton, VIC 3800, Australia.,Neuroscience Program, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia.,Australian Research Council, Centre of Excellence for Integrative Brain Function, Monash University Node, Clayton, VIC 3800, Australia
| | - Tristan A Chaplin
- Department of Physiology, Monash University, Clayton, VIC 3800, Australia.,Neuroscience Program, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia.,Australian Research Council, Centre of Excellence for Integrative Brain Function, Monash University Node, Clayton, VIC 3800, Australia.,Sainsbury Wellcome Centre for Neural Circuits and Behaviour, University College London, 25 Howland Street, London W1T 4JG, United Kingdom
| | - Krystel R Huxlin
- Flaum Eye Institute, University of Rochester, Rochester, NY 14642, USA
| | - Marcello G P Rosa
- Department of Physiology, Monash University, Clayton, VIC 3800, Australia.,Neuroscience Program, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia.,Australian Research Council, Centre of Excellence for Integrative Brain Function, Monash University Node, Clayton, VIC 3800, Australia
| | - Leo L Lui
- Department of Physiology, Monash University, Clayton, VIC 3800, Australia.,Neuroscience Program, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia.,Australian Research Council, Centre of Excellence for Integrative Brain Function, Monash University Node, Clayton, VIC 3800, Australia
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13
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Morimoto MM, Uchishiba E, Saleem AB. Organization of feedback projections to mouse primary visual cortex. iScience 2021; 24:102450. [PMID: 34113813 PMCID: PMC8169797 DOI: 10.1016/j.isci.2021.102450] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 02/01/2021] [Accepted: 04/14/2021] [Indexed: 11/17/2022] Open
Abstract
Top-down, context-dependent modulation of visual processing has been a topic of wide interest, including in mouse primary visual cortex (V1). However, the organization of feedback projections to V1 is relatively unknown. Here, we investigated inputs to mouse V1 by injecting retrograde tracers. We developed a software pipeline that maps labeled cell bodies to corresponding brain areas in the Allen Reference Atlas. We identified more than 24 brain areas that provide inputs to V1 and quantified the relative strength of their projections. We also assessed the organization of the projections, based on either the organization of cell bodies in the source area (topography) or the distribution of projections across V1 (bias). Projections from most higher visual and some nonvisual areas to V1 showed both topography and bias. Such organization of feedback projections to V1 suggests that parts of the visual field are differentially modulated by context, which can be ethologically relevant for a navigating animal.
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Affiliation(s)
- Mai M. Morimoto
- UCL Institute of Behavioural Neuroscience, Department of Experimental Psychology, University College London, London, WC1H 0AP, UK
| | - Emi Uchishiba
- UCL Institute of Behavioural Neuroscience, Department of Experimental Psychology, University College London, London, WC1H 0AP, UK
| | - Aman B. Saleem
- UCL Institute of Behavioural Neuroscience, Department of Experimental Psychology, University College London, London, WC1H 0AP, UK
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14
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Pavan A. Spatial and Temporal Selectivity of Translational Glass Patterns Assessed With the Tilt After-Effect. Iperception 2021; 12:20416695211017924. [PMID: 34104382 PMCID: PMC8172339 DOI: 10.1177/20416695211017924] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 04/27/2021] [Indexed: 11/16/2022] Open
Abstract
Glass patterns (GPs) have been widely employed to investigate the mechanisms underlying processing of global form from locally oriented cues. The current study aimed to psychophysically investigate the level at which global orientation is extracted from translational GPs using the tilt after-effect (TAE) and manipulating the spatiotemporal properties of the adapting pattern. We adapted participants to translational GPs and tested with sinewave gratings. In Experiment 1, we investigated whether orientation-selective units are sensitive to the temporal frequency of the adapting GP. We used static and dynamic translational GPs, with dynamic GPs refreshed at different temporal frequencies. In Experiment 2, we investigated the spatial frequency selectivity of orientation-selective units by manipulating the spatial frequency content of the adapting GPs. The results showed that the TAE peaked at a temporal frequency of ∼30 Hz, suggesting that orientation-selective units responding to translational GPs are sensitive to high temporal frequencies. In addition, TAE from translational GPs peaked at lower spatial frequencies than the dipoles' spatial constant. These effects are consistent with form-motion integration at low and intermediate levels of visual processing.
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Affiliation(s)
- Andrea Pavan
- Department of Psychology, University of
Bologna, Bologna, Italy; School of Psychology, University of Lincoln,
Lincoln, UK
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15
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Wu D, Zhou Y, Lv H, Liu N, Zhang P. The initial visual performance modulates the effects of anodal transcranial direct current stimulation over the primary visual cortex on the contrast sensitivity function. Neuropsychologia 2021; 156:107854. [PMID: 33823163 DOI: 10.1016/j.neuropsychologia.2021.107854] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 03/09/2021] [Accepted: 03/31/2021] [Indexed: 10/21/2022]
Abstract
Transcranial direct current stimulation (tDCS) has great potential to modulate cortical excitability and further facilitate visual function or rehabilitation. However, tDCS modulation effects are largely variable, possibly because of the individual differences in initial performance. The present study investigated the influence of the initial performance on contrast sensitivity function (CSF) following tDCS. Fifty healthy participants were randomly assigned to three groups: anodal, cathodal and sham stimulation. The CSF was measured through a grating detection task before and immediately after tDCS. Active and reference electrodes were applied to the primary occipital cortex (Oz) and the middle of the head (Cz) for 20 min with an intensity of 1.5 mA, respectively. Compared with sham stimulation, anodal or cathodal stimulation had no effect on the area under the log CSF (AULCSF) or contrast sensitivity (CS) of various spatial frequencies at the group level. However, a negative relationship was found between initial performance and the AULCSF change (or CS change at a spatial of frequency 8 c/°) after the application of anodal tDCS, indicating that the degree of change was dependent on initial performance, with greater gains observed for those with poorer initial performance. Initial performance modulated the effect of anodal tDCS over the Oz on the CSF, indicating that the Oz plays a crucial role in visual function. These results contribute to a deep understanding of the mechanisms of tDCS and to the design of more precise and efficient personalized simulation approaches based on individual differences.
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Affiliation(s)
- Di Wu
- Department of Medical Psychology, Air Force Medical University, Xi'an, China
| | - YingJie Zhou
- Basic Medical School, Air Force Medical University, Xi'an, China
| | - Haixu Lv
- Basic Medical School, Air Force Medical University, Xi'an, China
| | - Na Liu
- Department of Nursing, Air Force Medical University, Xi'an, China
| | - Pan Zhang
- Department of Psychology, Hebei Normal University, Shijiazhuang, China.
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16
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Yang Y, Chen K, Rosa MGP, Yu HH, Kuang LR, Yang J. Visual response characteristics of neurons in the second visual area of marmosets. Neural Regen Res 2021; 16:1871-1876. [PMID: 33510095 PMCID: PMC8328785 DOI: 10.4103/1673-5374.303043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The physiological characteristics of the marmoset second visual area (V2) are poorly understood compared with those of the primary visual area (V1). In this study, we observed the physiological response characteristics of V2 neurons in four healthy adult marmosets using intracortical tungsten microelectrodes. We recorded 110 neurons in area V2, with receptive fields located between 8° and 15° eccentricity. Most (88.2%) of these neurons were orientation selective, with half-bandwidths typically ranging between 10° and 30°. A significant proportion of neurons (28.2%) with direction selectivity had a direction index greater than 0.5. The vast majority of V2 neurons had separable spatial frequency and temporal frequency curves and, according to this criterion, they were not speed selective. The basic functional response characteristics of neurons in area V2 resemble those found in area V1. Our findings show that area V2 together with V1 are important in primate visual processing, especially in locating objects in space and in detecting an object’s direction of motion. The methods used in this study were approved by the Monash University Animal Ethics Committee, Australia (MARP 2009-2011) in 2009.
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Affiliation(s)
- Yin Yang
- Department of Ophthalmology, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital; College of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan Province, China
| | - Ke Chen
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, Sichuan Province, China
| | - Marcello G P Rosa
- Department of Physiology, Monash University, Melbourne, VIC, Australia
| | - Hsin-Hao Yu
- Department of Physiology, Monash University, Melbourne, VIC, Australia
| | - Li-Rong Kuang
- Chengdu Medical College, Chengdu, Sichuan Province, China
| | - Jie Yang
- College of Medicine, University of Electronic Science and Technology of China; Department of Neurology, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, Sichuan Province, China
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17
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Looming and receding visual networks in awake marmosets investigated with fMRI. Neuroimage 2020; 215:116815. [DOI: 10.1016/j.neuroimage.2020.116815] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 01/29/2020] [Accepted: 04/03/2020] [Indexed: 01/04/2023] Open
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18
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Wu D, Zhang P, Li C, Liu N, Jia W, Chen G, Ren W, Sun Y, Xiao W. Perceptual Learning at Higher Trained Cutoff Spatial Frequencies Induces Larger Visual Improvements. Front Psychol 2020; 11:265. [PMID: 32153473 PMCID: PMC7047335 DOI: 10.3389/fpsyg.2020.00265] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 02/04/2020] [Indexed: 12/29/2022] Open
Abstract
It is well known that extensive practice of a perceptual task can improve visual performance, termed perceptual learning. The goal of the present study was to evaluate the dependency of visual improvements on the features of training stimuli (i.e., spatial frequency). Twenty-eight observers were divided into training and control groups. Visual acuity (VA) and contrast sensitivity function (CSF) were measured and compared before and after training. All observers in the training group were trained in a monocular grating detection task near their individual cutoff spatial frequencies. The results showed that perceptual learning induced significant visual improvement, which was dependent on the cutoff spatial frequency, with a greater improvement magnitude and transfer of perceptual learning observed for those trained with higher spatial frequencies. However, VA significantly improved following training but was not related to the cutoff spatial frequency. The results may broaden the understanding of the nature of the learning rule and the neural plasticity of different cortical areas.
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Affiliation(s)
- Di Wu
- Department of Medical Psychology, Air Force Medical University, Xi'an, China
| | - Pan Zhang
- Department of Psychology, The Ohio State University, Columbus, OH, United States
| | - Chenxi Li
- School of Nursing, Yueyang Vocational Technical College, Yueyang, China
| | - Na Liu
- Department of Nursing, Air Force Medical University, Xi'an, China
| | - Wuli Jia
- Department of Psychology, School of Education Science, Huaiyin Normal University, Huai'an, China
| | - Ge Chen
- School of Arts and Design, Zhengzhou University of Light Industry, Zhengzhou, China
| | - Weicong Ren
- Department of Psychology, Hebei Normal University, Shijiazhuang, China
| | - Yuqi Sun
- Department of Systems Neuroscience, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Wei Xiao
- Department of Medical Psychology, Air Force Medical University, Xi'an, China
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19
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Aghajari S, Vinke LN, Ling S. Population spatial frequency tuning in human early visual cortex. J Neurophysiol 2020; 123:773-785. [PMID: 31940228 DOI: 10.1152/jn.00291.2019] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neurons within early visual cortex are selective for basic image statistics, including spatial frequency. However, these neurons are thought to act as band-pass filters, with the window of spatial frequency sensitivity varying across the visual field and across visual areas. Although a handful of previous functional (f)MRI studies have examined human spatial frequency sensitivity using conventional designs and analysis methods, these measurements are time consuming and fail to capture the precision of spatial frequency tuning (bandwidth). In this study, we introduce a model-driven approach to fMRI analyses that allows for fast and efficient estimation of population spatial frequency tuning (pSFT) for individual voxels. Blood oxygen level-dependent (BOLD) responses within early visual cortex were acquired while subjects viewed a series of full-field stimuli that swept through a large range of spatial frequency content. Each stimulus was generated by band-pass filtering white noise with a central frequency that changed periodically between a minimum of 0.5 cycles/degree (cpd) and a maximum of 12 cpd. To estimate the underlying frequency tuning of each voxel, we assumed a log-Gaussian pSFT and optimized the parameters of this function by comparing our model output against the measured BOLD time series. Consistent with previous studies, our results show that an increase in eccentricity within each visual area is accompanied by a drop in the peak spatial frequency of the pSFT. Moreover, we found that pSFT bandwidth depends on eccentricity and is correlated with the pSFT peak; populations with lower peaks possess broader bandwidths in logarithmic scale, whereas in linear scale this relationship is reversed.NEW & NOTEWORTHY Spatial frequency selectivity is a hallmark property of early visuocortical neurons, and mapping these sensitivities gives us crucial insight into the hierarchical organization of information within visual areas. Due to technical obstacles, we lack a comprehensive picture of the properties of this sensitivity in humans. Here, we introduce a new method, coined population spatial frequency tuning mapping, which circumvents the limitations of the conventional neuroimaging methods, yielding a fuller visuocortical map of spatial frequency sensitivity.
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Affiliation(s)
- Sara Aghajari
- Department of Psychological and Brain Sciences, Boston University, Boston, Massachusetts.,Center for Systems Neuroscience, Boston University, Boston, Massachusetts
| | - Louis N Vinke
- Center for Systems Neuroscience, Boston University, Boston, Massachusetts.,Graduate Program for Neuroscience, Boston University, Boston, Massachusetts
| | - Sam Ling
- Department of Psychological and Brain Sciences, Boston University, Boston, Massachusetts.,Center for Systems Neuroscience, Boston University, Boston, Massachusetts
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20
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Retinotopic specializations of cortical and thalamic inputs to area MT. Proc Natl Acad Sci U S A 2019; 116:23326-23331. [PMID: 31659044 DOI: 10.1073/pnas.1909799116] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Retinotopic specializations in the ventral visual stream, especially foveal adaptations, provide primates with high-acuity vision in the central visual field. However, visual field specializations have not been studied in the dorsal visual stream, dedicated to processing visual motion and visually guided behaviors. To investigate this, we injected retrograde neuronal tracers occupying the whole visuotopic representation of the middle temporal (MT) visual area in marmoset monkeys and studied the distribution and morphology of the afferent primary visual cortex (V1) projections. Contrary to previous reports, we found a heterogeneous population of V1-MT projecting neurons distributed in layers 3C and 6. In layer 3C, spiny stellate neurons were distributed mainly in foveal representations, while pyramidal morphologies were characteristic of peripheral eccentricities. This primate adaptation of the V1 to MT pathway is arranged in a way that we had not previously understood, with abundant stellate projection neurons in the high-resolution foveal portions, suggesting rapid relay of motion information to visual area MT. We also describe that the medial portion of the inferior pulvinar (PIm), which is the main thalamic input to area MT, shows a retinotopic organization, likely reflecting the importance of this pathway during development and the establishment of area MT topography.
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21
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To MPS, Carvey KM, Carvey RJ, Liu CH. Averaging sets of expressive faces is modulated by eccentricity. J Vis 2019; 19:2. [PMID: 31480073 DOI: 10.1167/19.11.2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Research has shown that participants can extract the average facial expression from a set of faces when these were presented at fixation. In this study, we investigated whether this performance would be modulated by eccentricity given that neural resources are limited outside the foveal region. We also examined whether or not there would be compulsory averaging in the parafovea as has been previously reported for the orientation of Gabor patches by Parkes, Lund, Angelucci, Solomon, and Morgan (2001). Participants were presented with expressive faces (alone or in sets of nine, at fixation or at 3° to the left or right) and were asked to identify the expression of the central target face or to estimate the average expression of the set. Our results revealed that, although participants were able to extract average facial expressions in central and parafoveal conditions, their performance was superior in the parafovea, suggesting facilitated averaging outside the fovea by peripheral mechanisms. Furthermore, regardless of whether the task was to judge the expression of the central target or set average, participants had a tendency to identify central targets' expressions in the fovea but were compelled to average in the parafovea, a finding consistent with compulsory averaging. The data also supported averaging over substitution models of crowding. We conclude that the ability to extract average expressions in sets of faces and identify single targets' facial expressions is influenced by eccentricity.
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Affiliation(s)
- Michelle P S To
- Department of Psychology, Lancaster University, Lancaster, UK.,Department of Psychology, University of Hull, Hull, UK
| | | | | | - Chang Hong Liu
- Department of Psychology Bournemouth University, Poole, UK.,Department of Psychology, University of Hull, Hull, UK
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22
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Pawar AS, Gepshtein S, Savel'ev S, Albright TD. Mechanisms of Spatiotemporal Selectivity in Cortical Area MT. Neuron 2019; 101:514-527.e2. [PMID: 30606614 PMCID: PMC6398985 DOI: 10.1016/j.neuron.2018.12.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 06/28/2018] [Accepted: 12/03/2018] [Indexed: 11/28/2022]
Abstract
Cortical sensory neurons are characterized by selectivity to stimulation. This selectivity was originally viewed as a part of the fundamental "receptive field" characteristic of neurons. This view was later challenged by evidence that receptive fields are modulated by stimuli outside of the classical receptive field. Here, we show that even this modified view of selectivity needs revision. We measured spatial frequency selectivity of neurons in cortical area MT of alert monkeys and found that their selectivity strongly depends on luminance contrast, shifting to higher spatial frequencies as contrast increases. The changes of preferred spatial frequency are large at low temporal frequency, and they decrease monotonically as temporal frequency increases. That is, even interactions among basic stimulus dimensions of luminance contrast, spatial frequency, and temporal frequency strongly influence neuronal selectivity. This dynamic nature of neuronal selectivity is inconsistent with the notion of stimulus preference as a stable characteristic of cortical neurons.
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Affiliation(s)
- Ambarish S Pawar
- Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
| | - Sergei Gepshtein
- Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA; Center for Spatial Perception and Concrete Experience, School of Cinematic Arts, University of Southern California, Los Angeles, CA 90089, USA
| | - Sergey Savel'ev
- Department of Physics, Loughborough University, Loughborough LE11 3TU, UK
| | - Thomas D Albright
- Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
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23
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Chaplin TA, Rosa MGP, Lui LL. Auditory and Visual Motion Processing and Integration in the Primate Cerebral Cortex. Front Neural Circuits 2018; 12:93. [PMID: 30416431 PMCID: PMC6212655 DOI: 10.3389/fncir.2018.00093] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 10/08/2018] [Indexed: 11/13/2022] Open
Abstract
The ability of animals to detect motion is critical for survival, and errors or even delays in motion perception may prove costly. In the natural world, moving objects in the visual field often produce concurrent sounds. Thus, it can highly advantageous to detect motion elicited from sensory signals of either modality, and to integrate them to produce more reliable motion perception. A great deal of progress has been made in understanding how visual motion perception is governed by the activity of single neurons in the primate cerebral cortex, but far less progress has been made in understanding both auditory motion and audiovisual motion integration. Here we, review the key cortical regions for motion processing, focussing on translational motion. We compare the representations of space and motion in the visual and auditory systems, and examine how single neurons in these two sensory systems encode the direction of motion. We also discuss the way in which humans integrate of audio and visual motion cues, and the regions of the cortex that may mediate this process.
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Affiliation(s)
- Tristan A Chaplin
- Neuroscience Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, VIC, Australia.,Australian Research Council (ARC) Centre of Excellence for Integrative Brain Function, Monash University Node, Clayton, VIC, Australia
| | - Marcello G P Rosa
- Neuroscience Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, VIC, Australia.,Australian Research Council (ARC) Centre of Excellence for Integrative Brain Function, Monash University Node, Clayton, VIC, Australia
| | - Leo L Lui
- Neuroscience Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, VIC, Australia.,Australian Research Council (ARC) Centre of Excellence for Integrative Brain Function, Monash University Node, Clayton, VIC, Australia
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24
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Samonds JM, Geisler WS, Priebe NJ. Natural image and receptive field statistics predict saccade sizes. Nat Neurosci 2018; 21:1591-1599. [PMID: 30349110 DOI: 10.1038/s41593-018-0255-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 09/19/2018] [Indexed: 11/09/2022]
Abstract
Humans and other primates sample the visual environment using saccadic eye movements that shift a high-resolution fovea toward regions of interest to create a clear perception of a scene across fixations. Many mammals, however, like mice, lack a fovea, which raises the question of why they make saccades. Here we describe and test the hypothesis that saccades are matched to natural scene statistics and to the receptive field sizes and adaptive properties of neural populations. Specifically, we determined the minimum amplitude of saccades in natural scenes necessary to provide uncorrelated inputs to model neural populations. This analysis predicts the distributions of observed saccade sizes during passive viewing for nonhuman primates, cats, and mice. Furthermore, disrupting the development of receptive field properties by monocular deprivation changed saccade sizes consistent with this hypothesis. Therefore, natural-scene statistics and the neural representation of natural images appear to be critical factors guiding saccadic eye movements.
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Affiliation(s)
- Jason M Samonds
- Department of Neuroscience, University of Texas at Austin, Austin, TX, USA. .,Center for Perceptual Systems, University of Texas at Austin, Austin, TX, USA. .,Center for Learning and Memory, University of Texas at Austin, Austin, TX, USA.
| | - Wilson S Geisler
- Department of Neuroscience, University of Texas at Austin, Austin, TX, USA.,Center for Perceptual Systems, University of Texas at Austin, Austin, TX, USA.,Department of Psychology, University of Texas at Austin, Austin, TX, USA
| | - Nicholas J Priebe
- Department of Neuroscience, University of Texas at Austin, Austin, TX, USA.,Center for Perceptual Systems, University of Texas at Austin, Austin, TX, USA.,Center for Learning and Memory, University of Texas at Austin, Austin, TX, USA
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25
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Nakai Y, Nagashima A, Hayakawa A, Osuki T, Jeong JW, Sugiura A, Brown EC, Asano E. Four-dimensional map of the human early visual system. Clin Neurophysiol 2017; 129:188-197. [PMID: 29190524 DOI: 10.1016/j.clinph.2017.10.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 09/29/2017] [Accepted: 10/06/2017] [Indexed: 11/30/2022]
Abstract
OBJECTIVE We generated a large-scale, four-dimensional map of neuronal modulations elicited by full-field flash stimulation. METHODS We analyzed electrocorticography (ECoG) recordings from 63 patients with focal epilepsy, and delineated the spatial-temporal dynamics of visually-elicited high-gamma70-110 Hz amplitudes on a standard brain template. We then clarified the neuronal events underlying visual evoked potential (VEP) components, by correlating with high-gamma amplitude measures. RESULTS The medial-occipital cortex initially revealed rapid neural activation followed by prolonged suppression, reflected by augmentation of high-gamma activity lasting up to 100 ms followed by attenuation lasting up to 1000 ms, respectively. With a number of covariate factors incorporated into a prediction model, the eccentricity representation independently predicted the magnitude of post-activation suppression, which was more intense in regions representing more parafoveal visual fields compared to those of more peripheral fields. The initial negative component on VEP was sharply contoured and co-occurred with early high-gamma augmentation, whose offset then co-occurred with a large positive VEP peak. A delayed negative VEP peak was blunt and co-occurred with prolonged high-gamma attenuation. CONCLUSIONS Eccentricity-dependent gradient in neural suppression in the medial-occipital region may explain the functional difference between peripheral and parafoveal/central vision. Early negative and positive VEP components may reflect neural activation, whereas a delayed negative VEP peak reflecting neural suppression. SIGNIFICANCE Our observation provides the mechanistic rationale for transient scotoma or mild flash-blindness, characterized by physiological afterimage preferentially formed in central vision following intense but non-injurious light exposure.
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Affiliation(s)
- Yasuo Nakai
- Department of Pediatrics, Wayne State University, Children's Hospital of Michigan, Detroit Medical Center, Detroit, MI 48201, USA; Department of Neurological Surgery, Wakayama Medical University, Wakayama-shi, Wakayama 6418510, Japan
| | - Akari Nagashima
- Department of Pediatrics, Wayne State University, Children's Hospital of Michigan, Detroit Medical Center, Detroit, MI 48201, USA
| | - Akane Hayakawa
- Department of Pediatrics, Wayne State University, Children's Hospital of Michigan, Detroit Medical Center, Detroit, MI 48201, USA
| | - Takuya Osuki
- Department of Pediatrics, Wayne State University, Children's Hospital of Michigan, Detroit Medical Center, Detroit, MI 48201, USA
| | - Jeong-Won Jeong
- Department of Pediatrics, Wayne State University, Children's Hospital of Michigan, Detroit Medical Center, Detroit, MI 48201, USA; Department of Neurology, Wayne State University, Children's Hospital of Michigan, Detroit Medical Center, Detroit, MI 48201, USA
| | - Ayaka Sugiura
- Department of Pediatrics, Wayne State University, Children's Hospital of Michigan, Detroit Medical Center, Detroit, MI 48201, USA
| | - Erik C Brown
- Department of Neurological Surgery, Oregon Health and Science University, Portland, OR 97239, USA
| | - Eishi Asano
- Department of Pediatrics, Wayne State University, Children's Hospital of Michigan, Detroit Medical Center, Detroit, MI 48201, USA; Department of Neurology, Wayne State University, Children's Hospital of Michigan, Detroit Medical Center, Detroit, MI 48201, USA.
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26
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Sawada T, Petrov AA. The divisive normalization model of V1 neurons: a comprehensive comparison of physiological data and model predictions. J Neurophysiol 2017; 118:3051-3091. [PMID: 28835531 DOI: 10.1152/jn.00821.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 08/21/2017] [Accepted: 08/21/2017] [Indexed: 01/24/2023] Open
Abstract
The physiological responses of simple and complex cells in the primary visual cortex (V1) have been studied extensively and modeled at different levels. At the functional level, the divisive normalization model (DNM; Heeger DJ. Vis Neurosci 9: 181-197, 1992) has accounted for a wide range of single-cell recordings in terms of a combination of linear filtering, nonlinear rectification, and divisive normalization. We propose standardizing the formulation of the DNM and implementing it in software that takes static grayscale images as inputs and produces firing rate responses as outputs. We also review a comprehensive suite of 30 empirical phenomena and report a series of simulation experiments that qualitatively replicate dozens of key experiments with a standard parameter set consistent with physiological measurements. This systematic approach identifies novel falsifiable predictions of the DNM. We show how the model simultaneously satisfies the conflicting desiderata of flexibility and falsifiability. Our key idea is that, while adjustable parameters are needed to accommodate the diversity across neurons, they must be fixed for a given individual neuron. This requirement introduces falsifiable constraints when this single neuron is probed with multiple stimuli. We also present mathematical analyses and simulation experiments that explicate some of these constraints.
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Affiliation(s)
- Tadamasa Sawada
- School of Psychology, National Research University Higher School of Economics, Moscow, Russia; and
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27
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Plasticity Beyond V1: Reinforcement of Motion Perception upon Binocular Central Retinal Lesions in Adulthood. J Neurosci 2017; 37:8989-8999. [PMID: 28821647 DOI: 10.1523/jneurosci.1231-17.2017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 08/03/2017] [Accepted: 08/08/2017] [Indexed: 11/21/2022] Open
Abstract
Induction of a central retinal lesion in both eyes of adult mammals is a model for macular degeneration and leads to retinotopic map reorganization in the primary visual cortex (V1). Here we characterized the spatiotemporal dynamics of molecular activity levels in the central and peripheral representation of five higher-order visual areas, V2/18, V3/19, V4/21a,V5/PMLS, area 7, and V1/17, in adult cats with central 10° retinal lesions (both sexes), by means of real-time PCR for the neuronal activity reporter gene zif268. The lesions elicited a similar, permanent reduction in activity in the center of the lesion projection zone of area V1/17, V2/18, V3/19, and V4/21a, but not in the motion-driven V5/PMLS, which instead displayed an increase in molecular activity at 3 months postlesion, independent of visual field coordinates. Also area 7 only displayed decreased activity in its LPZ in the first weeks postlesion and increased activities in its periphery from 1 month onward. Therefore we examined the impact of central vision loss on motion perception using random dot kinematograms to test the capacity for form from motion detection based on direction and velocity cues. We revealed that the central retinal lesions either do not impair motion detection or even result in better performance, specifically when motion discrimination was based on velocity discrimination. In conclusion, we propose that central retinal damage leads to enhanced peripheral vision by sensitizing the visual system for motion processing relying on feedback from V5/PMLS and area 7.SIGNIFICANCE STATEMENT Central retinal lesions, a model for macular degeneration, result in functional reorganization of the primary visual cortex. Examining the level of cortical reactivation with the molecular activity marker zif268 revealed reorganization in visual areas outside V1. Retinotopic lesion projection zones typically display an initial depression in zif268 expression, followed by partial recovery with postlesion time. Only the motion-sensitive area V5/PMLS shows no decrease, and even a significant activity increase at 3 months post-retinal lesion. Behavioral tests of motion perception found no impairment and even better sensitivity to higher random dot stimulus velocities. We demonstrate that the loss of central vision induces functional mobilization of motion-sensitive visual cortex, resulting in enhanced perception of moving stimuli.
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28
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Zhao C, Hata R, Okamura JY, Wang G. Differences in spatial and temporal frequency interactions between central and peripheral parts of the feline area 18. Eur J Neurosci 2016; 44:2635-2645. [PMID: 27529598 DOI: 10.1111/ejn.13372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 04/14/2016] [Accepted: 08/05/2016] [Indexed: 12/01/2022]
Abstract
The visual system demonstrates significant differences in information processing abilities between the central and peripheral parts of the visual field. Optical imaging based on intrinsic signals was used to investigate the difference in stimulus spatial and temporal frequency interactions related to receptive field eccentricity in the cat area 18. Changing either the spatial or the temporal frequency of grating stimuli had a significant impact on responses in the cortical areas corresponding to the centre of the visual field and more peripheral parts at 10 degrees eccentricity. The cortical region corresponding to the centre of the gaze was tuned to 0.4 cycles per degree (c/deg) for spatial frequency and 2 Hz for temporal frequency. In contrast, the cortical region corresponding to the periphery of the visual field was tuned to a lower spatial frequency of 0.15 c/deg and a higher temporal frequency of 4 Hz. Interestingly, when we simultaneously changed both the spatial frequency and the temporal frequency of the grating stimuli, the responses were significantly different from those estimated with an assumption of independence between the spatial and temporal frequency in the cortical region corresponding to the periphery of the visual field. However, in the cortical area corresponding to the centre of the gaze, spatial frequency showed significant independence from temporal frequency. These properties support the notion of relative specialization of visual information processing for peripheral representations in cortical areas.
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Affiliation(s)
- Chunzhen Zhao
- Department of Information Science and Biomedical Engineering, Graduate School of Science and Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima, 890-0065, Japan.,Laboratory for Cognitive Neuroscience, Weifang Medical University, Weifang, China
| | - Ryosuke Hata
- Department of Information Science and Biomedical Engineering, Graduate School of Science and Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima, 890-0065, Japan
| | - Jun-Ya Okamura
- Department of Information Science and Biomedical Engineering, Graduate School of Science and Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima, 890-0065, Japan
| | - Gang Wang
- Department of Information Science and Biomedical Engineering, Graduate School of Science and Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima, 890-0065, Japan. .,Laboratory for Cognitive Neuroscience, Weifang Medical University, Weifang, China.
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29
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Hagan MA, Rosa MGP, Lui LL. Neural plasticity following lesions of the primate occipital lobe: The marmoset as an animal model for studies of blindsight. Dev Neurobiol 2016; 77:314-327. [PMID: 27479288 DOI: 10.1002/dneu.22426] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 07/21/2016] [Accepted: 07/29/2016] [Indexed: 12/15/2022]
Abstract
For nearly a century it has been observed that some residual visually guided behavior can persist after damage to the primary visual cortex (V1) in primates. The age at which damage to V1 occurs leads to different outcomes, with V1 lesions in infancy allowing better preservation of visual faculties in comparison with those incurred in adulthood. While adult V1 lesions may still allow retention of some limited visual abilities, these are subconscious-a characteristic that has led to this form of residual vision being referred to as blindsight. The neural basis of blindsight has been of great interest to the neuroscience community, with particular focus on understanding the contributions of the different subcortical pathways and cortical areas that may underlie this phenomenon. More recently, research has started to address which forms of neural plasticity occur following V1 lesions at different ages, including work using marmoset monkeys. The relatively rapid postnatal development of this species, allied to the lissencephalic brains and well-characterized visual cortex provide significant technical advantages, which allow controlled experiments exploring visual function in the absence of V1. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 314-327, 2017.
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Affiliation(s)
- Maureen A Hagan
- Department of Physiology, Monash University, Victoria, 3800, Australia.,Neuroscience Program, Biomedicine Discovery Institute, Monash University, Victoria, 3800, Australia.,Australian Research Council, Centre of Excellence for Integrative Brain Function, Monash University Node, Victoria, 3800, Australia
| | - Marcello G P Rosa
- Department of Physiology, Monash University, Victoria, 3800, Australia.,Neuroscience Program, Biomedicine Discovery Institute, Monash University, Victoria, 3800, Australia.,Australian Research Council, Centre of Excellence for Integrative Brain Function, Monash University Node, Victoria, 3800, Australia
| | - Leo L Lui
- Department of Physiology, Monash University, Victoria, 3800, Australia.,Neuroscience Program, Biomedicine Discovery Institute, Monash University, Victoria, 3800, Australia.,Australian Research Council, Centre of Excellence for Integrative Brain Function, Monash University Node, Victoria, 3800, Australia
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30
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Pigarev IN, Levichkina EV. Absolute Depth Sensitivity in Cat Primary Visual Cortex under Natural Viewing Conditions. Front Syst Neurosci 2016; 10:66. [PMID: 27547179 PMCID: PMC4974279 DOI: 10.3389/fnsys.2016.00066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 07/21/2016] [Indexed: 11/13/2022] Open
Abstract
Mechanisms of 3D perception, investigated in many laboratories, have defined depth either relative to the fixation plane or to other objects in the visual scene. It is obvious that for efficient perception of the 3D world, additional mechanisms of depth constancy could operate in the visual system to provide information about absolute distance. Neurons with properties reflecting some features of depth constancy have been described in the parietal and extrastriate occipital cortical areas. It has also been shown that, for some neurons in the visual area V1, responses to stimuli of constant angular size differ at close and remote distances. The present study was designed to investigate whether, in natural free gaze viewing conditions, neurons tuned to absolute depths can be found in the primary visual cortex (area V1). Single-unit extracellular activity was recorded from the visual cortex of waking cats sitting on a trolley in front of a large screen. The trolley was slowly approaching the visual scene, which consisted of stationary sinusoidal gratings of optimal orientation rear-projected over the whole surface of the screen. Each neuron was tested with two gratings, with spatial frequency of one grating being twice as high as that of the other. Assuming that a cell is tuned to a spatial frequency, its maximum response to the grating with a spatial frequency twice as high should be shifted to a distance half way closer to the screen in order to attain the same size of retinal projection. For hypothetical neurons selective to absolute depth, location of the maximum response should remain at the same distance irrespective of the type of stimulus. It was found that about 20% of neurons in our experimental paradigm demonstrated sensitivity to particular distances independently of the spatial frequencies of the gratings. We interpret these findings as an indication of the use of absolute depth information in the primary visual cortex.
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Affiliation(s)
- Ivan N Pigarev
- Institute for Information Transmission Problems (Kharkevich Institute), Russian Academy of Sciences Moscow, Russia
| | - Ekaterina V Levichkina
- Institute for Information Transmission Problems (Kharkevich Institute), Russian Academy of SciencesMoscow, Russia; Department of Optometry and Vision Sciences, The University of Melbourne, ParkvilleVIC, Australia
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31
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Natural motion trajectory enhances the coding of speed in primate extrastriate cortex. Sci Rep 2016; 6:19739. [PMID: 26813361 PMCID: PMC4728434 DOI: 10.1038/srep19739] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 12/16/2015] [Indexed: 11/08/2022] Open
Abstract
The ability to estimate the speed of an object irrespective of size or texture is a crucial function of the visual system. However, previous studies have suggested that the neuronal coding of speed in the middle temporal area (MT, a key cortical area for motion analysis in primates) is ambiguous, with most neurons changing their speed tuning depending on the spatial frequency (SF) of a visual pattern. Here we demonstrate that the ability of MT neurons to encode speed is markedly improved when stimuli follow a trajectory across the visual field, prior to entering their receptive fields. We also show that this effect is much less marked in the primary visual area. These results indicate that MT neurons build up on computations performed at earlier levels of the visual system to provide accurate coding of speed in natural situations, and provide additional evidence that nonlinear pooling underlie motion processing.
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32
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Richard B, Johnson AP, Thompson B, Hansen BC. The Effects of tDCS Across the Spatial Frequencies and Orientations that Comprise the Contrast Sensitivity Function. Front Psychol 2015; 6:1784. [PMID: 26640448 PMCID: PMC4661264 DOI: 10.3389/fpsyg.2015.01784] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 11/05/2015] [Indexed: 12/13/2022] Open
Abstract
Transcranial Direct Current Stimulation (tDCS) has recently been employed in traditional psychophysical paradigms in an effort to measure direct manipulations on spatial frequency channel operations in the early visual system. However, the effects of tDCS on contrast sensitivity have only been measured at a single spatial frequency and orientation. Since contrast sensitivity is known to depend on spatial frequency and orientation, we ask how the effects of anodal and cathodal tDCS may vary according to these dimensions. We measured contrast sensitivity with sinusoidal gratings at four different spatial frequencies (0.5, 4, 8, and 12 cycles/°), two orientations (45° Oblique and Horizontal), and for two stimulus size conditions [fixed size (3°) and fixed period (1.5 cycles)]. Only contrast sensitivity measured with a 45° oblique grating with a spatial frequency of 8 cycles/° (period = 1.5 cycles) demonstrated clear polarity specific effects of tDCS, whereby cathodal tDCS increased and anodal tDCS decreased contrast sensitivity. Overall, effects of tDCS were largest for oblique stimuli presented at high spatial frequencies (i.e., 8 and 12 cycles/°), and were small or absent at lower spatial frequencies, other orientations and stimulus size. Thus, the impact of tDCS on contrast sensitivity, and therefore on spatial frequency channel operations, is opposite in direction to other behavioral effects of tDCS, and only measurable in stimuli that generally elicit lower contrast sensitivity (e.g., oblique gratings with period of 1.5 cycles at spatial frequencies above the peak of the contrast sensitivity function).
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Affiliation(s)
- Bruno Richard
- Department of Psychology, Concordia University, Montreal QC, Canada ; Department of Psychology, University of York York, UK
| | - Aaron P Johnson
- Department of Psychology, Concordia University, Montreal QC, Canada
| | - Benjamin Thompson
- School of Optometry and Vision Science, University of Waterloo, Waterloo ON, Canada ; School of Optometry and Vision Science, The University of Auckland Auckland, New Zealand
| | - Bruce C Hansen
- Department of Psychology and Neuroscience Program, Colgate University, Hamilton NY, USA
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33
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Tolhurst DJ. A commentary on 'Amplitude spectra of natural images'. Ophthalmic Physiol Opt 2015; 35:628-30. [PMID: 26497295 DOI: 10.1111/opo.12251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tolhurst, Tadmor and Tang Chao (Ophthalmic Physiol Opt 1992; 12: 229-232) published their analyses of the Fourier spectra of 135 digitised monochrome photographs of everyday scenes. In 2015, this would be a trivial exercise, but in 1992, this stretched emerging computer technology to its desktop limits. The short paper made an impact because it provided a handle for extending vision science beyond laboratory stimuli such as sinewave gratings into a real world of real visual scenes and real visual tasks.
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Affiliation(s)
- David J Tolhurst
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
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34
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Are visual peripheries forever young? Neural Plast 2015; 2015:307929. [PMID: 25945262 PMCID: PMC4402573 DOI: 10.1155/2015/307929] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 03/03/2015] [Accepted: 03/13/2015] [Indexed: 11/18/2022] Open
Abstract
The paper presents a concept of lifelong plasticity of peripheral vision. Central vision processing is accepted as critical and irreplaceable for normal perception in humans. While peripheral processing chiefly carries information about motion stimuli features and redirects foveal attention to new objects, it can also take over functions typical for central vision. Here I review the data showing the plasticity of peripheral vision found in functional, developmental, and comparative studies. Even though it is well established that afferent projections from central and peripheral retinal regions are not established simultaneously during early postnatal life, central vision is commonly used as a general model of development of the visual system. Based on clinical studies and visually deprived animal models, I describe how central and peripheral visual field representations separately rely on early visual experience. Peripheral visual processing (motion) is more affected by binocular visual deprivation than central visual processing (spatial resolution). In addition, our own experimental findings show the possible recruitment of coarse peripheral vision for fine spatial analysis. Accordingly, I hypothesize that the balance between central and peripheral visual processing, established in the course of development, is susceptible to plastic adaptations during the entire life span, with peripheral vision capable of taking over central processing.
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35
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Mitchell JF, Leopold DA. The marmoset monkey as a model for visual neuroscience. Neurosci Res 2015; 93:20-46. [PMID: 25683292 PMCID: PMC4408257 DOI: 10.1016/j.neures.2015.01.008] [Citation(s) in RCA: 141] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 01/16/2015] [Accepted: 01/16/2015] [Indexed: 11/26/2022]
Abstract
The common marmoset (Callithrix jacchus) has been valuable as a primate model in biomedical research. Interest in this species has grown recently, in part due to the successful demonstration of transgenic marmosets. Here we examine the prospects of the marmoset model for visual neuroscience research, adopting a comparative framework to place the marmoset within a broader evolutionary context. The marmoset's small brain bears most of the organizational features of other primates, and its smooth surface offers practical advantages over the macaque for areal mapping, laminar electrode penetration, and two-photon and optical imaging. Behaviorally, marmosets are more limited at performing regimented psychophysical tasks, but do readily accept the head restraint that is necessary for accurate eye tracking and neurophysiology, and can perform simple discriminations. Their natural gaze behavior closely resembles that of other primates, with a tendency to focus on objects of social interest including faces. Their immaturity at birth and routine twinning also makes them ideal for the study of postnatal visual development. These experimental factors, together with the theoretical advantages inherent in comparing anatomy, physiology, and behavior across related species, make the marmoset an excellent model for visual neuroscience.
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Affiliation(s)
- Jude F Mitchell
- Brain and Cognitive Sciences Department, Meliora Hall, University of Rochester, Rochester, NY 14627, USA.
| | - David A Leopold
- Section on Cognitive Neurophysiology and Imaging, Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA; Neurophysiology Imaging Facility, National Institute of Mental Health, National Institute of Neurological Disorders and Stroke, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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36
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Structure and function of the middle temporal visual area (MT) in the marmoset: Comparisons with the macaque monkey. Neurosci Res 2015; 93:62-71. [DOI: 10.1016/j.neures.2014.09.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 09/16/2014] [Accepted: 09/16/2014] [Indexed: 11/22/2022]
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37
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Yu HH, Chaplin TA, Rosa MGP. Representation of central and peripheral vision in the primate cerebral cortex: Insights from studies of the marmoset brain. Neurosci Res 2014; 93:47-61. [PMID: 25242578 DOI: 10.1016/j.neures.2014.09.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 08/27/2014] [Accepted: 08/28/2014] [Indexed: 01/06/2023]
Abstract
How the visual field is represented by neurons in the cerebral cortex is one of the most basic questions in visual neuroscience. However, research to date has focused heavily on the small part of the visual field within, and immediately surrounding the fovea. Studies on the cortical representation of the full visual field in the primate brain are still scarce. We have been investigating this issue with electrophysiological and anatomical methods, taking advantage of the small and lissencephalic marmoset brain, which allows easy access to the representation of the full visual field in many cortical areas. This review summarizes our main findings to date, and relates the results to a broader question: is the peripheral visual field processed in a similar manner to the central visual field, but with lower spatial acuity? Given the organization of the visual cortex, the issue can be addressed by asking: (1) Is visual information processed in the same way within a single cortical area? and (2) Are different cortical areas specialized for different parts of the visual field? The electrophysiological data from the primary visual cortex indicate that many aspects of spatiotemporal computation are remarkably similar across the visual field, although subtle variations are detectable. Our anatomical and electrophysiological studies of the extrastriate cortex, on the other hand, suggest that visual processing in the far peripheral visual field is likely to involve a distinct network of specialized cortical areas, located in the depths of the calcarine sulcus and interhemispheric fissure.
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Affiliation(s)
- H-H Yu
- Department of Physiology, Monash University, Clayton, VIC 3800, Australia; Australian Research Council Centre of Excellence for Integrative Brain Function, Monash University Node, Clayton, VIC 3800, Australia.
| | - T A Chaplin
- Department of Physiology, Monash University, Clayton, VIC 3800, Australia; Monash Vision Group, Monash University, Clayton, VIC 3800, Australia
| | - M G P Rosa
- Department of Physiology, Monash University, Clayton, VIC 3800, Australia; Australian Research Council Centre of Excellence for Integrative Brain Function, Monash University Node, Clayton, VIC 3800, Australia; Monash Vision Group, Monash University, Clayton, VIC 3800, Australia
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38
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Laskowska-Macios K, Zapasnik M, Hu TT, Kossut M, Arckens L, Burnat K. Zif268 mRNA Expression Patterns Reveal a Distinct Impact of Early Pattern Vision Deprivation on the Development of Primary Visual Cortical Areas in the Cat. Cereb Cortex 2014; 25:3515-26. [PMID: 25205660 PMCID: PMC4585500 DOI: 10.1093/cercor/bhu192] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Pattern vision deprivation (BD) can induce permanent deficits in global motion perception. The impact of timing and duration of BD on the maturation of the central and peripheral visual field representations in cat primary visual areas 17 and 18 remains unknown. We compared early BD, from eye opening for 2, 4, or 6 months, with late onset BD, after 2 months of normal vision, using the expression pattern of the visually driven activity reporter gene zif268 as readout. Decreasing zif268 mRNA levels between months 2 and 4 characterized the normal maturation of the (supra)granular layers of the central and peripheral visual field representations in areas 17 and 18. In general, all BD conditions had higher than normal zif268 levels. In area 17, early BD induced a delayed decrease, beginning later in peripheral than in central area 17. In contrast, the decrease occurred between months 2 and 4 throughout area 18. Lack of pattern vision stimulation during the first 4 months of life therefore has a different impact on the development of areas 17 and 18. A high zif268 expression level at a time when normal vision is restored seems to predict the capacity of a visual area to compensate for BD.
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Affiliation(s)
- Karolina Laskowska-Macios
- Laboratory of Neuroplasticity, Nencki Institute of Experimental Biology, Warsaw 02-093, Poland Laboratory of Neuroplasticity and Neuroproteomics, KU Leuven-University of Leuven, Leuven 3000, Belgium
| | - Monika Zapasnik
- Laboratory of Neuroplasticity, Nencki Institute of Experimental Biology, Warsaw 02-093, Poland
| | - Tjing-Tjing Hu
- Laboratory of Neuroplasticity and Neuroproteomics, KU Leuven-University of Leuven, Leuven 3000, Belgium
| | - Malgorzata Kossut
- Laboratory of Neuroplasticity, Nencki Institute of Experimental Biology, Warsaw 02-093, Poland
| | - Lutgarde Arckens
- Laboratory of Neuroplasticity and Neuroproteomics, KU Leuven-University of Leuven, Leuven 3000, Belgium
| | - Kalina Burnat
- Laboratory of Neuroplasticity, Nencki Institute of Experimental Biology, Warsaw 02-093, Poland
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Solomon SG, Rosa MGP. A simpler primate brain: the visual system of the marmoset monkey. Front Neural Circuits 2014; 8:96. [PMID: 25152716 PMCID: PMC4126041 DOI: 10.3389/fncir.2014.00096] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 07/22/2014] [Indexed: 12/15/2022] Open
Abstract
Humans are diurnal primates with high visual acuity at the center of gaze. Although primates share many similarities in the organization of their visual centers with other mammals, and even other species of vertebrates, their visual pathways also show unique features, particularly with respect to the organization of the cerebral cortex. Therefore, in order to understand some aspects of human visual function, we need to study non-human primate brains. Which species is the most appropriate model? Macaque monkeys, the most widely used non-human primates, are not an optimal choice in many practical respects. For example, much of the macaque cerebral cortex is buried within sulci, and is therefore inaccessible to many imaging techniques, and the postnatal development and lifespan of macaques are prohibitively long for many studies of brain maturation, plasticity, and aging. In these and several other respects the marmoset, a small New World monkey, represents a more appropriate choice. Here we review the visual pathways of the marmoset, highlighting recent work that brings these advantages into focus, and identify where additional work needs to be done to link marmoset brain organization to that of macaques and humans. We will argue that the marmoset monkey provides a good subject for studies of a complex visual system, which will likely allow an important bridge linking experiments in animal models to humans.
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Affiliation(s)
- Samuel G Solomon
- Department of Experimental Psychology, University College London London, UK
| | - Marcello G P Rosa
- Department of Physiology, Monash University, Clayton, VIC Australia ; Monash Vision Group, Monash University, Clayton, VIC Australia ; Australian Research Council Centre of Excellence for Integrative Brain Function, Monash University Node, Clayton, VIC Australia
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40
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Solomon SS, Chen SC, Morley JW, Solomon SG. Local and Global Correlations between Neurons in the Middle Temporal Area of Primate Visual Cortex. Cereb Cortex 2014; 25:3182-96. [DOI: 10.1093/cercor/bhu111] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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41
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Abstract
The common marmoset (Callithrix jacchus), a small-bodied New World primate, offers several advantages to complement vision research in larger primates. Studies in the anesthetized marmoset have detailed the anatomy and physiology of their visual system (Rosa et al., 2009) while studies of auditory and vocal processing have established their utility for awake and behaving neurophysiological investigations (Lu et al., 2001a,b; Eliades and Wang, 2008a,b; Osmanski and Wang, 2011; Remington et al., 2012). However, a critical unknown is whether marmosets can perform visual tasks under head restraint. This has been essential for studies in macaques, enabling both accurate eye tracking and head stabilization for neurophysiology. In one set of experiments we compared the free viewing behavior of head-fixed marmosets to that of macaques, and found that their saccadic behavior is comparable across a number of saccade metrics and that saccades target similar regions of interest including faces. In a second set of experiments we applied behavioral conditioning techniques to determine whether the marmoset could control fixation for liquid reward. Two marmosets could fixate a central point and ignore peripheral flashing stimuli, as needed for receptive field mapping. Both marmosets also performed an orientation discrimination task, exhibiting a saturating psychometric function with reliable performance and shorter reaction times for easier discriminations. These data suggest that the marmoset is a viable model for studies of active vision and its underlying neural mechanisms.
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42
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Uniformity and diversity of response properties of neurons in the primary visual cortex: selectivity for orientation, direction of motion, and stimulus size from center to far periphery. Vis Neurosci 2013; 31:85-98. [PMID: 24160942 DOI: 10.1017/s0952523813000448] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Although the primary visual cortex (V1) is one of the most extensively studied areas of the primate brain, very little is known about how the far periphery of visual space is represented in this area. We characterized the physiological response properties of V1 neurons in anaesthetized marmoset monkeys, using high-contrast drifting gratings. Comparisons were made between cells with receptive fields located in three regions of V1, defined by eccentricity: central (3-5°), near peripheral (5-15°), and far peripheral (>50°). We found that orientation selectivity of individual cells was similar from the center to the far periphery. Nonetheless, the proportion of orientation-selective neurons was higher in central visual field representation than in the peripheral representations. In addition, there were similar proportions of cells representing all orientations, with the exception of the representation of the far periphery, where we detected a bias favoring near-horizontal orientations. The proportions of direction-selective cells were similar throughout V1. When the center/surround organization of the receptive fields was tested with gratings with varying diameters, we found that the population of neurons that was suppressed by large gratings was smaller in the far periphery, although the strength of suppression in these cells tended to be stronger. In addition, the ratio between the diameters of the excitatory centers and suppressive surrounds was similar across the entire visual field. These results suggest that, superimposed on the broad uniformity of V1, there are subtle physiological differences, which indicate that spatial information is processed differently in the central versus far peripheral visual fields.
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43
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Visually evoked responses in extrastriate area MT after lesions of striate cortex in early life. J Neurosci 2013; 33:12479-89. [PMID: 23884952 DOI: 10.1523/jneurosci.0844-13.2013] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Lesions of striate cortex [primary visual cortex (V1)] in adult primates result in blindness. In contrast, V1 lesions in neonates typically allow much greater preservation of vision, including, in many human patients, conscious perception. It is presently unknown how this marked functional difference is related to physiological changes in cortical areas that are spared by the lesions. Here we report a study of the middle temporal area (MT) of adult marmoset monkeys that received unilateral V1 lesions within 6 weeks of birth. In contrast with observations after similar lesions in adult monkeys, we found that virtually all neurons in the region of MT that was deprived of V1 inputs showed robust responses to visual stimulation. These responses were very similar to those recorded in neurons with receptive fields outside the lesion projection zones in terms of firing rate, signal-to-noise ratio, and latency. In addition, the normal retinotopic organization of MT was maintained. Nonetheless, we found evidence of a very specific functional deficit: direction selectivity, a key physiological characteristic of MT that is known to be preserved in many cells after adult V1 lesions, was absent. These results demonstrate that lesion-induced reorganization of afferent pathways is sufficient to develop robust visual function in primate extrastriate cortex, highlighting a likely mechanism for the sparing of vision after neonatal V1 lesions. However, they also suggest that interactions with V1 in early postnatal life are critical for establishing stimulus selectivity in MT.
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44
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Chaplin TA, Yu HH, Rosa MGP. Representation of the visual field in the primary visual area of the marmoset monkey: magnification factors, point-image size, and proportionality to retinal ganglion cell density. J Comp Neurol 2013; 521:1001-19. [PMID: 22911425 DOI: 10.1002/cne.23215] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 07/25/2012] [Accepted: 08/14/2012] [Indexed: 11/11/2022]
Abstract
The primary visual area (V1) forms a systematic map of the visual field, in which adjacent cell clusters represent adjacent points of visual space. A precise quantification of this map is key to understanding the anatomical relationships between neurons located in different stations of the visual pathway, as well as the neural bases of visual performance in different regions of the visual field. We used computational methods to quantify the visual topography of V1 in the marmoset (Callithrix jacchus), a small diurnal monkey. The receptive fields of neurons throughout V1 were mapped in two anesthetized animals using electrophysiological recordings. Following histological reconstruction, precise 3D reconstructions of the V1 surface and recording sites were generated. We found that the areal magnification factor (M(A) ) decreases with eccentricity following a function that has the same slope as that observed in larger diurnal primates, including macaque, squirrel, and capuchin monkeys, and humans. However, there was no systematic relationship between M(A) and polar angle. Despite individual variation in the shape of V1, the relationship between M(A) and eccentricity was preserved across cases. Comparison between V1 and the retinal ganglion cell density demonstrated preferential magnification of central space in the cortex. The size of the cortical compartment activated by a punctiform stimulus decreased from the foveal representation towards the peripheral representation. Nonetheless, the relationship between the receptive field sizes of V1 cells and the density of ganglion cells suggested that each V1 cell receives information from a similar number of retinal neurons, throughout the visual field.
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Affiliation(s)
- Tristan A Chaplin
- Department of Physiology, Monash University, Clayton, VIC 3800, Australia
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45
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Botelho EP, Ceriatte C, Soares JGM, Gattass R, Fiorani M. Quantification of early stages of cortical reorganization of the topographic map of V1 following retinal lesions in monkeys. Cereb Cortex 2012; 24:1-16. [PMID: 23010747 PMCID: PMC3862261 DOI: 10.1093/cercor/bhs208] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
We quantified the capacity for reorganization of the topographic representation of area V1 in adult monkeys. Bias-free automated mapping methods were used to delineate receptive fields (RFs) of an array of neuronal clusters prior to, and up to 6 h following retinal lesions. Monocular lesions caused a significant reorganization of the topographic map in this area, both inside and outside the cortical lesion projection zone (LPZ). Small flashed stimuli revealed responses up to 0.85 mm inside the boundaries of the LPZ, with RFs representing regions of undamaged retina immediately surrounding the lesion. In contrast, long moving bars that spanned the scotoma resulting from the lesion revealed responsive units up to 1.87 mm inside the LPZ, with RFs representing interpolated responses in this region. This reorganization is present immediately after monocular retinal lesioning. Both stimuli showed a similar and significant (5-fold) increase of the RF scatter in the LPZ, 0.56 mm (median), compared with the undamaged retina, 0.12 mm. Our results reveal an array of preexisting subthreshold functional connections of up to 2 mm in V1, which can be rapidly mobilized independently from the differential qualitative reorganization elicited by each stimulus.
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Affiliation(s)
- Eliã P Botelho
- Programa de Neurobiologia, Universidade Federal do Rio de Janeiro, Instituto de Biofísica Carlos Chagas Filho, Rio de Janeiro, RJ 21941-900, Brazil
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46
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Ledue EE, Zou MY, Crowder NA. Spatiotemporal tuning in mouse primary visual cortex. Neurosci Lett 2012; 528:165-9. [PMID: 22995183 DOI: 10.1016/j.neulet.2012.09.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 08/29/2012] [Accepted: 09/01/2012] [Indexed: 11/17/2022]
Abstract
The neural correlates of visual motion perception have historically been studied in non-human primates. However, the mouse has recently gained popularity as a model for studying vision primarily driven by the hope that the genetic tools available in this species may contribute to our understanding of visual processing in the cortex. A recent calcium-imaging study on the spatiotemporal tuning of mouse striate and extrastriate cortex revealed that neurons in the primary visual cortex (V1) were almost never speed tuned, whereas previous electrophysiological studies in macaques noted around one quarter of V1 neurons appeared to be selective for a particular stimulus speed. We were interested in whether this discrepancy was due to methodological or species differences, so we measured the spatiotemporal tuning of mouse V1 neurons using standard electrophysiological techniques. Using comparable analyses to previous studies of speed tuning, our data showed that speed tuning is rare in mouse V1, which corroborates earlier studies in mouse and points to a species difference in motion processing in early cortex between macaques and other mammals.
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Affiliation(s)
- E E Ledue
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
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47
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Uchimura K, Okamura JY, Wang G. Surround modulation in cortical orientation map revealed by optical imaging and its dependency on receptive field eccentricity. Eur J Neurosci 2012; 36:3344-55. [DOI: 10.1111/j.1460-9568.2012.08248.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Yu HH, Chaplin TA, Davies AJ, Verma R, Rosa MGP. A specialized area in limbic cortex for fast analysis of peripheral vision. Curr Biol 2012; 22:1351-7. [PMID: 22704993 DOI: 10.1016/j.cub.2012.05.029] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 05/14/2012] [Accepted: 05/14/2012] [Indexed: 02/06/2023]
Abstract
In primates, prostriata is a small area located between the primary visual cortex (V1) and the hippocampal formation. Prostriata sends connections to multisensory and high-order association areas in the temporal, parietal, cingulate, orbitofrontal, and frontopolar cortices. It is characterized by a relatively simple histological organization, alluding to an early origin in mammalian evolution. Here we show that prostriata neurons in marmoset monkeys exhibit a unique combination of response properties, suggesting a new pathway for rapid distribution of visual information in parallel with the traditionally recognized dorsal and ventral streams. Whereas the location and known connections of prostriata suggest a high-level association area, its response properties are unexpectedly simple, resembling those found in early stages of the visual processing: neurons have robust, nonadapting responses to simple stimuli, with latencies comparable to those found in V1, and are broadly tuned to stimulus orientation and spatiotemporal frequency. However, their receptive fields are enormous and form a unique topographic map that emphasizes the far periphery of the visual field. These results suggest a specialized circuit through which stimuli in peripheral vision can bypass the elaborate hierarchy of extrastriate visual areas and rapidly elicit coordinated motor and cognitive responses across multiple brain systems.
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Affiliation(s)
- Hsin-Hao Yu
- Department of Physiology, Monash University, Clayton, Victoria 3800, Australia.
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49
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Hansen BC, Hess RF. On the effectiveness of noise masks: naturalistic vs. un-naturalistic image statistics. Vision Res 2012; 60:101-13. [PMID: 22484251 DOI: 10.1016/j.visres.2012.03.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Revised: 01/10/2012] [Accepted: 03/23/2012] [Indexed: 11/28/2022]
Abstract
It has been argued that the human visual system is optimized for identification of broadband objects embedded in stimuli possessing orientation averaged power spectra fall-offs that obey the 1/f(β) relationship typically observed in natural scene imagery (i.e., β=2.0 on logarithmic axes). Here, we were interested in whether individual spatial channels leading to recognition are functionally optimized for narrowband targets when masked by noise possessing naturalistic image statistics (β=2.0). The current study therefore explores the impact of variable β noise masks on the identification of narrowband target stimuli ranging in spatial complexity, while simultaneously controlling for physical or perceived differences between the masks. The results show that β=2.0 noise masks produce the largest identification thresholds regardless of target complexity, and thus do not seem to yield functionally optimized channel processing. The differential masking effects are discussed in the context of contrast gain control.
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Affiliation(s)
- Bruce C Hansen
- Department of Psychology & Neuroscience Program, Colgate University, Hamilton, NY 13346, USA.
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50
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Nishimoto S, Vu AT, Naselaris T, Benjamini Y, Yu B, Gallant JL. Reconstructing visual experiences from brain activity evoked by natural movies. Curr Biol 2011; 21:1641-6. [PMID: 21945275 DOI: 10.1016/j.cub.2011.08.031] [Citation(s) in RCA: 388] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 07/23/2011] [Accepted: 08/15/2011] [Indexed: 01/16/2023]
Abstract
Quantitative modeling of human brain activity can provide crucial insights about cortical representations [1, 2] and can form the basis for brain decoding devices [3-5]. Recent functional magnetic resonance imaging (fMRI) studies have modeled brain activity elicited by static visual patterns and have reconstructed these patterns from brain activity [6-8]. However, blood oxygen level-dependent (BOLD) signals measured via fMRI are very slow [9], so it has been difficult to model brain activity elicited by dynamic stimuli such as natural movies. Here we present a new motion-energy [10, 11] encoding model that largely overcomes this limitation. The model describes fast visual information and slow hemodynamics by separate components. We recorded BOLD signals in occipitotemporal visual cortex of human subjects who watched natural movies and fit the model separately to individual voxels. Visualization of the fit models reveals how early visual areas represent the information in movies. To demonstrate the power of our approach, we also constructed a Bayesian decoder [8] by combining estimated encoding models with a sampled natural movie prior. The decoder provides remarkable reconstructions of the viewed movies. These results demonstrate that dynamic brain activity measured under naturalistic conditions can be decoded using current fMRI technology.
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Affiliation(s)
- Shinji Nishimoto
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
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