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You FH, Gong XM, Sun Q. Serial dependencies between form orientation and motion direction are asymmetric. Front Psychol 2023; 14:1248307. [PMID: 37744576 PMCID: PMC10512465 DOI: 10.3389/fpsyg.2023.1248307] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 08/25/2023] [Indexed: 09/26/2023] Open
Abstract
Much work has been done to uncover the mechanisms underlying form and motion information integration. However, no study examined the symmetry of the integration of form and motion across the temporal domain (i.e., serial dependence). In Experiment 1, we presented form and motion displays sequentially. In the form displays, dot pairs were oriented toward one screen position, indicating the form orientation; in the motion displays, dots moved radially outward. Their motion trajectories were oriented toward one screen position, indicating the motion direction. In each trial, participants reported their perceived form orientation after the form display or their perceived motion direction after the motion display. We found that the current trial's perceived motion direction was biased toward the previous trial's form orientation and vice versa, indicating serial dependencies between form orientation and motion direction. In Experiment 2, we changed the form and motion displays' reliability by varying the two displays' dot densities. The results showed that the serial dependence of form orientation on motion direction perception decreased only with increasing the current motion display's reliability; neither the reliability of the previous motion display nor that of the current form display significantly affected the serial dependence of motion direction on form orientation perception. Hence, serial dependencies between form orientation and motion direction were asymmetric. Our across-temporal integrations between form and motion, together with the simultaneous integration of form and motion revealed in the previous studies, depict a comprehensive mechanism underlying the integration of the two pieces of information.
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Affiliation(s)
- Fan-Huan You
- School of Psychology, Zhejiang Normal University, Jinhua, China
| | - Xiu-Mei Gong
- School of Psychology, Zhejiang Normal University, Jinhua, China
| | - Qi Sun
- School of Psychology, Zhejiang Normal University, Jinhua, China
- Key Laboratory of Intelligent Education Technology and Application of Zhejiang Province, Zhejiang Normal University, Jinhua, China
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2
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Li VJ, Chorghay Z, Ruthazer ES. A Guide for the Multiplexed: The Development of Visual Feature Maps in the Brain. Neuroscience 2023; 508:62-75. [PMID: 35952996 DOI: 10.1016/j.neuroscience.2022.07.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 07/21/2022] [Accepted: 07/27/2022] [Indexed: 01/17/2023]
Abstract
Neural maps are found ubiquitously in the brain, where they encode a wide range of behaviourally relevant features into neural space. Developmental studies have shown that animals devote a great deal of resources to establish consistently patterned organization in neural circuits throughout the nervous system, but what purposes maps serve beneath their often intricate appearance and composition is a topic of active debate and exploration. In this article, we review the general mechanisms of map formation, with a focus on the visual system, and then survey notable organizational properties of neural maps: the multiplexing of feature representations through a nested architecture, the interspersing of fine-scale heterogeneity within a globally smooth organization, and the complex integration at the microcircuit level that enables a high dimensionality of information encoding. Finally, we discuss the roles of maps in cortical functions, including input segregation, feature extraction and routing of circuit outputs for higher order processing, as well as the evolutionary basis for the properties we observe in neural maps.
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Affiliation(s)
- Vanessa J Li
- Montreal Neurological Institute-Hospital, McGill University, 3801 University St. Montreal, Quebec H3A 2B4, Canada
| | - Zahraa Chorghay
- Montreal Neurological Institute-Hospital, McGill University, 3801 University St. Montreal, Quebec H3A 2B4, Canada
| | - Edward S Ruthazer
- Montreal Neurological Institute-Hospital, McGill University, 3801 University St. Montreal, Quebec H3A 2B4, Canada
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Fracasso A, Dumoulin SO, Petridou N. Point-spread function of the BOLD response across columns and cortical depth in human extra-striate cortex. Prog Neurobiol 2021; 207:102187. [PMID: 34798198 DOI: 10.1016/j.pneurobio.2021.102187] [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] [Indexed: 11/28/2022]
Abstract
Columns and layers are fundamental organizational units of the brain. Well known examples of cortical columns are the ocular dominance columns (ODCs) in primary visual cortex and the column-like stripe-based arrangement in the second visual area V2. The spatial scale of columns and layers is beyond the reach of conventional neuroimaging, but the advent of high field magnetic resonance imaging (MRI) scanners (UHF, 7 Tesla and above) has opened the possibility to acquire data at this spatial scale, in-vivo and non-invasively in humans. The most prominent non-invasive technique to measure brain function is blood oxygen level dependent (BOLD) fMRI, measuring brain activity indirectly, via changes in hemodynamics. A key determinant of the ability of high-resolution BOLD fMRI to accurately resolve columns and layers is the point-spread function (PSF) of the BOLD response in relation to the spatial extent of neuronal activity. In this study we take advantage of the stripe-based arrangement present in visual area V2, coupled with sub-millimetre anatomical and gradient-echo BOLD (GE BOLD) acquisition at 7 T to obtain PSF estimates and along cortical depth in human participants. Results show that the BOLD PSF is maximal in the superficial part of the cortex (1.78 mm), and it decreases with increasing cortical depth (0.83 mm close to white matter).
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Affiliation(s)
- Alessio Fracasso
- University of Glasgow, Institute of Neuroscience and Psychology, Glasgow, Scotland, United Kingdom.
| | - Serge O Dumoulin
- Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, the Netherlands; Spinoza Center for Neuroimaging, Amsterdam, the Netherlands; Experimental and Applied Psychology, VU University Amsterdam, the Netherlands
| | - Natalia Petridou
- Department of Radiology, Center for Image Sciences, University Medical Center Utrecht, 3584 CX, Utrecht, the Netherlands.
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Meier AM, Wang Q, Ji W, Ganachaud J, Burkhalter A. Modular Network between Postrhinal Visual Cortex, Amygdala, and Entorhinal Cortex. J Neurosci 2021; 41:4809-4825. [PMID: 33849948 PMCID: PMC8260166 DOI: 10.1523/jneurosci.2185-20.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 04/02/2021] [Accepted: 04/07/2021] [Indexed: 11/21/2022] Open
Abstract
The postrhinal area (POR) is a known center for integrating spatial with nonspatial visual information and a possible hub for influencing landmark navigation by affective input from the amygdala. This may involve specific circuits within muscarinic acetylcholine receptor 2 (M2)-positive (M2+) or M2- modules of POR that associate inputs from the thalamus, cortex, and amygdala, and send outputs to the entorhinal cortex. Using anterograde and retrograde labeling with conventional and viral tracers in male and female mice, we found that all higher visual areas of the ventral cortical stream project to the amygdala, while such inputs are absent from primary visual cortex and dorsal stream areas. Unexpectedly for the presumed salt-and-pepper organization of mouse extrastriate cortex, tracing results show that inputs from the dorsal lateral geniculate nucleus and lateral posterior nucleus were spatially clustered in layer 1 (L1) and overlapped with M2+ patches of POR. In contrast, input from the amygdala to L1 of POR terminated in M2- interpatches. Importantly, the amygdalocortical input to M2- interpatches in L1 overlapped preferentially with spatially clustered apical dendrites of POR neurons projecting to amygdala and entorhinal area lateral, medial (ENTm). The results suggest that subnetworks in POR, used to build spatial maps for navigation, do not receive direct thalamocortical M2+ patch-targeting inputs. Instead, they involve local networks of M2- interpatches, which are influenced by affective information from the amygdala and project to ENTm, whose cells respond to visual landmark cues for navigation.SIGNIFICANCE STATEMENT A central purpose of visual object recognition is identifying the salience of objects and approaching or avoiding them. However, it is not currently known how the visual cortex integrates the multiple streams of information, including affective and navigational cues, which are required to accomplish this task. We find that in a higher visual area, the postrhinal cortex, the cortical sheet is divided into interdigitating modules receiving distinct inputs from visual and emotion-related sources. One of these modules is preferentially connected with the amygdala and provides outputs to entorhinal cortex, constituting a processing stream that may assign emotional salience to objects and landmarks for the guidance of goal-directed navigation.
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Affiliation(s)
- Andrew M Meier
- Department of Neuroscience, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110
| | - Quanxin Wang
- Department of Neuroscience, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110
| | - Weiqing Ji
- Department of Neuroscience, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110
| | - Jehan Ganachaud
- Department of Neuroscience, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110
| | - Andreas Burkhalter
- Department of Neuroscience, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110
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5
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Fracasso A, Dumoulin SO, Petridou N. Point-spread function of the BOLD response across columns and cortical depth in human extra-striate cortex. Prog Neurobiol 2021; 202:102034. [PMID: 33741401 DOI: 10.1016/j.pneurobio.2021.102034] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 03/08/2021] [Accepted: 03/14/2021] [Indexed: 10/21/2022]
Abstract
Columns and layers are fundamental organizational units of the brain. Well known examples of cortical columns are the ocular dominance columns (ODCs) in primary visual cortex and the column-like stripe-based arrangement in the second visual area V2. The spatial scale of columns and layers is beyond the reach of conventional neuroimaging, but the advent of high field magnetic resonance imaging (MRI) scanners (UHF, 7 T and above) has opened the possibility to acquire data at this spatial scale, in-vivo and non-invasively in humans. The most prominent non-invasive technique to measure brain function is blood oxygen level dependent (BOLD) fMRI, measuring brain activity indirectly, via changes in hemodynamics. A key determinant of the ability of high-resolution BOLD fMRI to accurately resolve columns and layers is the point-spread function (PSF) of the BOLD response in relation to the spatial extent of neuronal activity. In this study we take advantage of the stripe-based arrangement present in visual area V2, coupled with sub-millimetre anatomical and gradient-echo BOLD (GE BOLD) acquisition at 7 T to obtain PSF estimates and along cortical depth in human participants. Results show that the BOLD PSF is maximal in the superficial part of the cortex (1.78 mm), and it decreases with increasing cortical depth (0.83 mm close to white matter).
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Affiliation(s)
- Alessio Fracasso
- University of Glasgow, Institute of Neuroscience and Psychology, Glasgow, Scotland, United Kingdom.
| | - Serge O Dumoulin
- Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, the Netherlands; Spinoza Center for Neuroimaging, Amsterdam, the Netherlands; Experimental and Applied Psychology, VU University Amsterdam, the Netherlands
| | - Natalia Petridou
- Department of Radiology, Center for Image Sciences, University Medical Center Utrecht, 3584 CX, Utrecht, the Netherlands.
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Tootell RBH, Nasr S. Scotopic Vision Is Selectively Processed in Thick-Type Columns in Human Extrastriate Cortex. Cereb Cortex 2021; 31:1163-1181. [PMID: 33073288 PMCID: PMC7786355 DOI: 10.1093/cercor/bhaa284] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 07/25/2020] [Accepted: 08/17/2020] [Indexed: 11/26/2022] Open
Abstract
In humans, visual stimuli can be perceived across an enormous range of light levels. Evidence suggests that different neural mechanisms process different subdivisions of this range. For instance, in the retina, stimuli presented at very low (scotopic) light levels activate rod photoreceptors, whereas cone photoreceptors are activated relatively more at higher (photopic) light levels. Similarly, different retinal ganglion cells are activated by scotopic versus photopic stimuli. However, in the brain, it remains unknown whether scotopic versus photopic information is: 1) processed in distinct channels, or 2) neurally merged. Using high-resolution functional magnetic resonance imaging at 7 T, we confirmed the first hypothesis. We first localized thick versus thin-type columns within areas V2, V3, and V4, based on photopic selectivity to motion versus color, respectively. Next, we found that scotopic stimuli selectively activated thick- (compared to thin-) type columns in V2 and V3 (in measurements of both overlap and amplitude) and V4 (based on overlap). Finally, we found stronger resting-state functional connections between scotopically dominated area MT with thick- (compared to thin-) type columns in areas V2, V3, and V4. We conclude that scotopic stimuli are processed in partially segregated parallel streams, emphasizing magnocellular influence, from retina through middle stages of visual cortex.
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Affiliation(s)
- Roger B H Tootell
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Radiology, Harvard Medical School, Boston, MA 02115, USA
| | - Shahin Nasr
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Radiology, Harvard Medical School, Boston, MA 02115, USA
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Liu Y, Li M, Zhang X, Lu Y, Gong H, Yin J, Chen Z, Qian L, Yang Y, Andolina IM, Shipp S, Mcloughlin N, Tang S, Wang W. Hierarchical Representation for Chromatic Processing across Macaque V1, V2, and V4. Neuron 2020; 108:538-550.e5. [PMID: 32853551 DOI: 10.1016/j.neuron.2020.07.037] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 05/09/2020] [Accepted: 07/28/2020] [Indexed: 11/26/2022]
Abstract
The perception of color is an internal label for the inferred spectral reflectance of visible surfaces. To study how spectral representation is transformed through modular subsystems of successive cortical areas, we undertook simultaneous optical imaging of intrinsic signals in macaque V1, V2, and V4, supplemented by higher-resolution electrophysiology and two-photon imaging in awake macaques. We find a progressive evolution in the scale and precision of chromotopic maps, expressed by a uniform blob-like architecture of hue responses within each area. Two-photon imaging reveals enhanced hue-specific cell clustering in V2 compared with V1. A phenomenon of endspectral (red and blue) responses that is clear in V1, recedes in V2, and is virtually absent in V4. The increase in mid- and extra-spectral hue representations through V2 and V4 reflects the nature of hierarchical processing as higher areas read out locations in chromatic space from progressive integration of signals relayed by V1.
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Affiliation(s)
- Ye Liu
- Institute of Neuroscience, Key Laboratory of Primate Neurobiology, Chinese Academy of Sciences Center for Excellence in Brain Science and Intelligence Technology, State Key Laboratory of Neuroscience, Chinese Academy of Sciences, Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ming Li
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing 100875, China
| | - Xian Zhang
- Institute of Neuroscience, Key Laboratory of Primate Neurobiology, Chinese Academy of Sciences Center for Excellence in Brain Science and Intelligence Technology, State Key Laboratory of Neuroscience, Chinese Academy of Sciences, Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai 200031, China; Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Yiliang Lu
- Institute of Neuroscience, Key Laboratory of Primate Neurobiology, Chinese Academy of Sciences Center for Excellence in Brain Science and Intelligence Technology, State Key Laboratory of Neuroscience, Chinese Academy of Sciences, Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai 200031, China
| | - Hongliang Gong
- Institute of Neuroscience, Key Laboratory of Primate Neurobiology, Chinese Academy of Sciences Center for Excellence in Brain Science and Intelligence Technology, State Key Laboratory of Neuroscience, Chinese Academy of Sciences, Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiapeng Yin
- Institute of Neuroscience, Key Laboratory of Primate Neurobiology, Chinese Academy of Sciences Center for Excellence in Brain Science and Intelligence Technology, State Key Laboratory of Neuroscience, Chinese Academy of Sciences, Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai 200031, China
| | - Zheyuan Chen
- Institute of Neuroscience, Key Laboratory of Primate Neurobiology, Chinese Academy of Sciences Center for Excellence in Brain Science and Intelligence Technology, State Key Laboratory of Neuroscience, Chinese Academy of Sciences, Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai 200031, China
| | - Liling Qian
- Institute of Neuroscience, Key Laboratory of Primate Neurobiology, Chinese Academy of Sciences Center for Excellence in Brain Science and Intelligence Technology, State Key Laboratory of Neuroscience, Chinese Academy of Sciences, Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai 200031, China
| | - Yupeng Yang
- Chinese Academy of Sciences Key Laboratory of Brain Function and Diseases, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Ian Max Andolina
- Institute of Neuroscience, Key Laboratory of Primate Neurobiology, Chinese Academy of Sciences Center for Excellence in Brain Science and Intelligence Technology, State Key Laboratory of Neuroscience, Chinese Academy of Sciences, Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai 200031, China
| | - Stewart Shipp
- Institute of Neuroscience, Key Laboratory of Primate Neurobiology, Chinese Academy of Sciences Center for Excellence in Brain Science and Intelligence Technology, State Key Laboratory of Neuroscience, Chinese Academy of Sciences, Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai 200031, China
| | - Niall Mcloughlin
- Division of Pharmacy and Optometry, Faculty of Biology, Medicine, and Health Science, University of Manchester, Manchester M13 9PL, UK
| | - Shiming Tang
- Peking University School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Beijing 100871, China; IDG/McGovern Institute for Brain Research at Peking University, Beijing 100871, China.
| | - Wei Wang
- Institute of Neuroscience, Key Laboratory of Primate Neurobiology, Chinese Academy of Sciences Center for Excellence in Brain Science and Intelligence Technology, State Key Laboratory of Neuroscience, Chinese Academy of Sciences, Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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Schuhmann T, Kemmerer SK, Duecker F, de Graaf TA, ten Oever S, De Weerd P, Sack AT. Left parietal tACS at alpha frequency induces a shift of visuospatial attention. PLoS One 2019; 14:e0217729. [PMID: 31774818 PMCID: PMC6881009 DOI: 10.1371/journal.pone.0217729] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 11/12/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Voluntary shifts of visuospatial attention are associated with a lateralization of parieto-occipital alpha power (7-13Hz), i.e. higher power in the hemisphere ipsilateral and lower power contralateral to the locus of attention. Recent noninvasive neuromodulation studies demonstrated that alpha power can be experimentally increased using transcranial alternating current stimulation (tACS). OBJECTIVE/HYPOTHESIS We hypothesized that tACS at alpha frequency over the left parietal cortex induces shifts of attention to the left hemifield. However, spatial attention shifts not only occur voluntarily (endogenous/ top-down), but also stimulus-driven (exogenous/ bottom-up). To study the task-specificity of the potential effects of tACS on attentional processes, we administered three conceptually different spatial attention tasks. METHODS 36 healthy volunteers were recruited from an academic environment. In two separate sessions, we applied either high-density tACS at 10Hz, or sham tACS, for 35-40 minutes to their left parietal cortex. We systematically compared performance on endogenous attention, exogenous attention, and stimulus detection tasks. RESULTS In the endogenous attention task, a greater leftward bias in reaction times was induced during left parietal 10Hz tACS as compared to sham. There were no stimulation effects in either the exogenous attention or the stimulus detection task. CONCLUSION The study demonstrates that high-density tACS at 10Hz can be used to modulate visuospatial attention performance. The tACS effect is task-specific, indicating that not all forms of attention are equally susceptible to the stimulation.
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Affiliation(s)
- Teresa Schuhmann
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Brain Imaging Center, Maastricht, The Netherlands
| | - Selma K. Kemmerer
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Brain Imaging Center, Maastricht, The Netherlands
| | - Felix Duecker
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Brain Imaging Center, Maastricht, The Netherlands
| | - Tom A. de Graaf
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Brain Imaging Center, Maastricht, The Netherlands
| | - Sanne ten Oever
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Brain Imaging Center, Maastricht, The Netherlands
| | - Peter De Weerd
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Brain Imaging Center, Maastricht, The Netherlands
| | - Alexander T. Sack
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
- Brain Imaging Center, Maastricht, The Netherlands
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNs), Brain + Nerve Centre, Maastricht University Medical Centre+ (MUMC+), Maastricht, The Netherlands
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D'Souza RD, Bista P, Meier AM, Ji W, Burkhalter A. Spatial Clustering of Inhibition in Mouse Primary Visual Cortex. Neuron 2019; 104:588-600.e5. [PMID: 31623918 DOI: 10.1016/j.neuron.2019.09.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 08/08/2019] [Accepted: 09/12/2019] [Indexed: 12/12/2022]
Abstract
Whether mouse visual cortex contains orderly feature maps is debated. The overlapping pattern of geniculocortical inputs with M2 muscarinic acetylcholine receptor-rich patches in layer 1 (L1) suggests a non-random architecture. Here, we found that L1 inputs from the lateral posterior thalamus (LP) avoid patches and target interpatches. Channelrhodopsin-2-assisted mapping of excitatory postsynaptic currents (EPSCs) in L2/3 shows that the relative excitation of parvalbumin-expressing interneurons (PVs) and pyramidal neurons (PNs) by dLGN, LP, and cortical feedback is distinct and depends on whether the neurons reside in clusters aligned with patches or interpatches. Paired recordings from PVs and PNs show that unitary inhibitory postsynaptic currents (uIPSCs) are larger in interpatches than in patches. The spatial clustering of inhibition is matched by dense clustering of PV terminals in interpatches. The results show that the excitation/inhibition balance across V1 is organized into patch and interpatch subnetworks, which receive distinct long-range inputs and are specialized for the processing of distinct spatiotemporal features.
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Affiliation(s)
- Rinaldo D D'Souza
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Pawan Bista
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Andrew M Meier
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Weiqing Ji
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Andreas Burkhalter
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA.
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10
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Morphological Cell Types Projecting from V1 Layer 4B to V2 Thick and Thin Stripes. J Neurosci 2019; 39:7501-7512. [PMID: 31358652 DOI: 10.1523/jneurosci.1096-19.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 07/16/2019] [Accepted: 07/19/2019] [Indexed: 11/21/2022] Open
Abstract
In macaque visual cortex, different cytochrome oxidase stripes of area V2 receive segregated projections from layers (L)2/3 and 4B of the primary visual cortex (V1), and project to dorsal or ventral stream extrastriate areas. Parallel V1-to-V2 pathways suggest functionally specialized circuits, but it is unknown whether these circuits arise from distinct cell types. V1 L4B includes two morphological types of excitatory projection neurons: pyramids, which carry mixed magnocellular (M) and parvocellular (P) information to downstream areas, and spiny stellates, which carry only M information. Previous studies have shown that, overall, V2 receives ∼80% of its L4B inputs from pyramids, thus receiving mixed M and P signals. However, it is unknown how pyramids and stellates distribute their outputs to the different V2 stripes, and whether different stripes receive inputs from morphologically distinct neuron types. Using viral-mediated labeling of V2-projecting L4B neurons in male macaques, we show that thick stripes receive a greater contribution of L4B inputs from M-dominated spiny stellates compared with thin stripes. Both stripe types, however, receive a much larger contribution from spiny stellates than previously shown for V2 overall, indicating that a larger amount of M information than previously thought flows into both the dorsal and ventral streams via the V2 thick and thin stripes, respectively. Moreover, we identify four types of V2-projecting L4B cells differing in size and complexity. Three such cell types project to both thin and thick stripes, but one type, the giant spiny-stellate neuron, resembling L4B neurons projecting to motion-sensitive area MT, was only found to project to thick stripes.SIGNIFICANCE STATEMENT Area V1 partitions visual information into functionally specialized parallel pathways which terminate into distinct stripes of area V2. We asked whether V1 inputs to different V2 stripes arise from morphologically different cell types. V1 layer (L)4B has two cell types: pyramids, which carry both magnocellular (M) and parvocellular (P) visual signals, and spiny stellates, which carry only M signals. We find that V2 thick stripes, which project to areas processing object motion, receive a larger fraction of L4B input from M-dominated stellates compared with thin stripes, which project to areas processing object attributes. We also identify four morphological types of V2-projecting L4B neurons, suggestive of four functionally specialized cell types.
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11
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Roe AW. Columnar connectome: toward a mathematics of brain function. Netw Neurosci 2019; 3:779-791. [PMID: 31410379 PMCID: PMC6663318 DOI: 10.1162/netn_a_00088] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 04/14/2019] [Indexed: 01/09/2023] Open
Abstract
Understanding brain networks is important for many fields, including neuroscience, psychology, medicine, and artificial intelligence. To address this fundamental need, there are multiple ongoing connectome projects in the United States, Europe, and Asia producing brain connection maps with resolutions at macro- and microscales. However, still lacking is a mesoscale connectome. This viewpoint (1) explains the need for a mesoscale connectome in the primate brain (the columnar connectome), (2) presents a new method for acquiring such data rapidly on a large scale, and (3) proposes how one might use such data to achieve a mathematics of brain function.
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Affiliation(s)
- Anna Wang Roe
- Institute of Interdisciplinary Neuroscience and Technology, Zhejiang University, Hangzhou, China
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12
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Local Circuits of V1 Layer 4B Neurons Projecting to V2 Thick Stripes Define Distinct Cell Classes and Avoid Cytochrome Oxidase Blobs. J Neurosci 2017; 37:422-436. [PMID: 28077720 DOI: 10.1523/jneurosci.2848-16.2016] [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: 09/09/2016] [Revised: 10/23/2016] [Accepted: 11/21/2016] [Indexed: 01/15/2023] Open
Abstract
Decades of anatomical studies on the primate primary visual cortex (V1) have led to a detailed diagram of V1 intrinsic circuitry, but this diagram lacks information about the output targets of V1 cells. Understanding how V1 local processing relates to downstream processing requires identification of neuronal populations defined by their output targets. In primates, V1 layers (L)2/3 and 4B send segregated projections to distinct cytochrome oxidase (CO) stripes in area V2: neurons in CO blob columns project to thin stripes while neurons outside blob columns project to thick and pale stripes, suggesting functional specialization of V1-to-V2 CO streams. However, the conventional diagram of V1 shows all L4B neurons, regardless of their soma location in blob or interblob columns, as projecting selectively to CO blobs in L2/3, suggesting convergence of blob/interblob information in L2/3 blobs and, possibly, some V2 stripes. However, it is unclear whether all L4B projection neurons show similar local circuitries. Using viral-mediated circuit tracing, we have identified the local circuits of L4B neurons projecting to V2 thick stripes in macaque. Consistent with previous studies, we found the somata of this L4B subpopulation to reside predominantly outside blob columns; however, unlike previous descriptions of local L4B circuits, these cells consistently projected outside CO blob columns in all layers. Thus, the local circuits of these L4B output neurons, just like their extrinsic projections to V2, preserve CO streams. Moreover, the intra-V1 laminar patterns of axonal projections identify two distinct neuron classes within this L4B subpopulation, including a rare novel neuron type, suggestive of two functionally specialized output channels. SIGNIFICANCE STATEMENT Conventional diagrams of primate primary visual cortex (V1) depict neuronal connections within and between different V1 layers, but lack information about the cells' downstream targets. This information is critical to understanding how local processing in V1 relates to downstream processing. We have identified the local circuits of a population of cells in V1 layer (L)4B that project to area V2. These cells' local circuits differ from classical descriptions of L4B circuits in both the laminar and functional compartments targeted by their axons, and identify two neuron classes. Our results demonstrate that both local intra-V1 and extrinsic V1-to-V2 connections of L4B neurons preserve CO-stream segregation, suggesting that across-stream integration occurs downstream of V1, and that output targets dictate local V1 circuitry.
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Columnar Segregation of Magnocellular and Parvocellular Streams in Human Extrastriate Cortex. J Neurosci 2017; 37:8014-8032. [PMID: 28724749 PMCID: PMC5559769 DOI: 10.1523/jneurosci.0690-17.2017] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 07/05/2017] [Accepted: 07/09/2017] [Indexed: 11/21/2022] Open
Abstract
Magnocellular versus parvocellular (M-P) streams are fundamental to the organization of macaque visual cortex. Segregated, paired M-P streams extend from retina through LGN into V1. The M stream extends further into area V5/MT, and parts of V2. However, elsewhere in visual cortex, it remains unclear whether M-P-derived information (1) becomes intermixed or (2) remains segregated in M-P-dominated columns and neurons. Here we tested whether M-P streams exist in extrastriate cortical columns, in 8 human subjects (4 female). We acquired high-resolution fMRI at high field (7T), testing for M- and P-influenced columns within each of four cortical areas (V2, V3, V3A, and V4), based on known functional distinctions in M-P streams in macaque: (1) color versus luminance, (2) binocular disparity, (3) luminance contrast sensitivity, (4) peak spatial frequency, and (5) color/spatial interactions. Additional measurements of resting state activity (eyes closed) tested for segregated functional connections between these columns. We found M- and P-like functions and connections within and between segregated cortical columns in V2, V3, and (in most experiments) area V4. Area V3A was dominated by the M stream, without significant influence from the P stream. These results suggest that M-P streams exist, and extend through, specific columns in early/middle stages of human extrastriate cortex.SIGNIFICANCE STATEMENT The magnocellular and parvocellular (M-P) streams are fundamental components of primate visual cortical organization. These streams segregate both anatomical and functional properties in parallel, from retina through primary visual cortex. However, in most higher-order cortical sites, it is unknown whether such M-P streams exist and/or what form those streams would take. Moreover, it is unknown whether M-P streams exist in human cortex. Here, fMRI evidence measured at high field (7T) and high resolution revealed segregated M-P streams in four areas of human extrastriate cortex. These results suggest that M-P information is processed in segregated parallel channels throughout much of human visual cortex; the M-P streams are more than a convenient sorting property in earlier stages of the visual system.
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Dumoulin SO, Harvey BM, Fracasso A, Zuiderbaan W, Luijten PR, Wandell BA, Petridou N. In vivo evidence of functional and anatomical stripe-based subdivisions in human V2 and V3. Sci Rep 2017; 7:733. [PMID: 28389654 PMCID: PMC5428808 DOI: 10.1038/s41598-017-00634-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 03/08/2017] [Indexed: 11/15/2022] Open
Abstract
Visual cortex contains a hierarchy of visual areas. The earliest cortical area (V1) contains neurons responding to colour, form and motion. Later areas specialize on processing of specific features. The second visual area (V2) in non-human primates contains a stripe-based anatomical organization, initially defined using cytochrome-oxidase staining of post-mortem tissue. Neurons in these stripes have been proposed to serve distinct functional specializations, e.g. processing of color, form and motion. These stripes represent an intermediate stage in visual hierarchy and serve a key role in the increasing functional specialization of visual areas. Using sub-millimeter high-field functional and anatomical MRI (7T), we provide in vivo evidence for stripe-based subdivisions in humans. Using functional MRI, we contrasted responses elicited by stimuli alternating at slow and fast temporal frequencies. We revealed stripe-based subdivisions in V2 ending at the V1/V2 border. The human stripes reach into V3. Using anatomical MRI optimized for myelin contrast within gray matter, we also observe a stripe pattern. Stripe subdivisions preferentially responding to fast temporal frequencies are more myelinated. As such, functional and anatomical measures provide independent and converging evidence for functional organization into striped-based subdivisions in human V2 and V3.
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Affiliation(s)
- Serge O Dumoulin
- Department of Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, Netherlands.
- Spinoza Centre for Neuroimaging, Amsterdam, Netherlands.
| | - Ben M Harvey
- Department of Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, Netherlands
| | - Alessio Fracasso
- Department of Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, Netherlands
- Spinoza Centre for Neuroimaging, Amsterdam, Netherlands
- Department of Radiology, University Medical Centre, Utrecht, Netherlands
| | - Wietske Zuiderbaan
- Department of Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, Netherlands
| | - Peter R Luijten
- Department of Radiology, University Medical Centre, Utrecht, Netherlands
| | - Brian A Wandell
- Department of Psychology, Stanford University, California, USA
| | - Natalia Petridou
- Department of Radiology, University Medical Centre, Utrecht, Netherlands
- Brain Center Rudolf Magnus, University Medical Centre Utrecht, Utrecht, Netherlands
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Zhang Y, Zhang X, Wang Y, Fang F. Misbinding of color and motion in human early visual cortex: Evidence from event-related potentials. Vision Res 2016; 122:51-59. [PMID: 27038562 DOI: 10.1016/j.visres.2015.12.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 09/13/2015] [Accepted: 12/29/2015] [Indexed: 11/25/2022]
Abstract
One of the central tasks for the visual system is to integrate visual features into objects, which is referred to as the binding problem. To study the binding mechanisms, it has been suggested to use phenomena of feature misbinding to separate active feature binding from feature co-occurence. Taking advantage of a steady-state misbinding of color and motion, we performed psychophysical and event-related potential (ERP) adaptation experiments to investigate the neural mechanisms of the misbinding (i.e., the active color-motion binding). Human subjects adapted to the misbinding of color and motion, as well as their correct binding that was used for identifying neural processes associated with the co-occurrence of color and motion. We found that adaptation to the misbinding and the correct binding could generate color-contingent motion aftereffects (CCMAEs), but in opposite directions. ERP adaptation effects manifested in the earliest ERP component C1. The C1 latency in the misbinding condition was 11ms longer than that in the correct binding condition. In the correct binding condition, the C1 adaptation effect (i.e., the C1 amplitude reduction after adaptation) took place in the peak phase of the C1. The dipole source of the adaptation effect was located in V1. In the misbinding condition, the C1 adaptation effect occurred in the descending phase of the C1 and its dipole source was in V2. In both conditions, the C1 adaptation effects correlated with the CCMAEs across individual subjects. These findings provide human electrophysiological evidence that active feature binding takes place in early visual cortex, but at later processing stages than feature co-occurrence.
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Affiliation(s)
- Yanyu Zhang
- Department of Psychology and Key Laboratory of Machine Perception (Ministry of Education), Peking University, Beijing 100871, PR China; Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing 100871, PR China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, PR China; PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, PR China
| | - Xilin Zhang
- Department of Psychology and Key Laboratory of Machine Perception (Ministry of Education), Peking University, Beijing 100871, PR China; Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing 100871, PR China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, PR China; PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, PR China
| | - Yizhou Wang
- National Engineering Laboratory for Video Technology, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, PR China
| | - Fang Fang
- Department of Psychology and Key Laboratory of Machine Perception (Ministry of Education), Peking University, Beijing 100871, PR China; Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing 100871, PR China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, PR China; PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, PR China.
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Smith GB, Whitney DE, Fitzpatrick D. Modular Representation of Luminance Polarity in the Superficial Layers of Primary Visual Cortex. Neuron 2016; 88:805-18. [PMID: 26590348 DOI: 10.1016/j.neuron.2015.10.019] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 09/23/2015] [Accepted: 10/06/2015] [Indexed: 10/22/2022]
Abstract
The spatial arrangement of luminance increments (ON) and decrements (OFF) falling on the retina provides a wealth of information used by central visual pathways to construct coherent representations of visual scenes. But how the polarity of luminance change is represented in the activity of cortical circuits remains unclear. Using wide-field epifluorescence and two-photon imaging we demonstrate a robust modular representation of luminance polarity (ON or OFF) in the superficial layers of ferret primary visual cortex. Polarity-specific domains are found with both uniform changes in luminance and single light/dark edges, and include neurons selective for orientation and direction of motion. The integration of orientation and polarity preference is evident in the selectivity and discrimination capabilities of most layer 2/3 neurons. We conclude that polarity selectivity is an integral feature of layer 2/3 neurons, ensuring that the distinction between light and dark stimuli is available for further processing in downstream extrastriate areas.
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Affiliation(s)
- Gordon B Smith
- Department of Functional Architecture and Development of Cerebral Cortex, Max Planck Florida Institute for Neuroscience, Jupiter, FL 33458, USA
| | - David E Whitney
- Department of Functional Architecture and Development of Cerebral Cortex, Max Planck Florida Institute for Neuroscience, Jupiter, FL 33458, USA
| | - David Fitzpatrick
- Department of Functional Architecture and Development of Cerebral Cortex, Max Planck Florida Institute for Neuroscience, Jupiter, FL 33458, USA.
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17
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Nascimento-Silva S, Pinõn C, Soares JGM, Gattass R. Feedforward and feedback connections and their relation to the cytox modules of V2 in Cebus monkeys. J Comp Neurol 2015; 522:3091-105. [PMID: 24585707 PMCID: PMC4233920 DOI: 10.1002/cne.23571] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 12/06/2013] [Accepted: 02/26/2014] [Indexed: 11/12/2022]
Abstract
To study the circuitry related to the ventral stream of visual information processing and its relation to the cytochrome oxidase (CytOx) modules in visual area V2, we injected anterograde and retrograde cholera toxin subunit B (CTb) tracer into nine sites in area V4 in five Cebus apella monkeys. The injection site locations ranged from 2° to 10° eccentricity in the lower visual field representation of V4. Alternate cortical sections, cut tangentially to the pial surface or in the coronal plane, were stained for CTb immunocytochemistry or for CytOx histochemistry or for Nissl. Our results indicate that the V4-projecting cells and terminal-like labeling were located in interstripes and thin CytOx-rich stripes and avoided the CytOx-rich thick stripes in V2. The feedforward projecting cell bodies in V2 were primarily located in the supragranular layers and sparsely located in the infragranular layers, whereas the feedback projections (i.e., the terminal-like labels) were located in the supra- and infragranular layers. V4 injections of CTb resulted in labeling of the thin stripes and interstripes of V2 and provided an efficient method of distinguishing the V2 modules that were related to the ventral stream from the CytOx-rich thick stripes, related to the dorsal stream. In V2, there was a significant heterogeneity in the distribution of projections: feedforward projections were located in CytOx-rich thin stripes and in the CytOx-poor interstripes, whereas the feedback projections were more abundant in the thin stripes than in the interstripes. J. Comp. Neurol. 522:3091–3105, 2014.
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Affiliation(s)
- Sheila Nascimento-Silva
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, 21949-900, Brazil
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Early monocular defocus disrupts the normal development of receptive-field structure in V2 neurons of macaque monkeys. J Neurosci 2015; 34:13840-54. [PMID: 25297110 DOI: 10.1523/jneurosci.1992-14.2014] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Experiencing different quality images in the two eyes soon after birth can cause amblyopia, a developmental vision disorder. Amblyopic humans show the reduced capacity for judging the relative position of a visual target in reference to nearby stimulus elements (position uncertainty) and often experience visual image distortion. Although abnormal pooling of local stimulus information by neurons beyond striate cortex (V1) is often suggested as a neural basis of these deficits, extrastriate neurons in the amblyopic brain have rarely been studied using microelectrode recording methods. The receptive field (RF) of neurons in visual area V2 in normal monkeys is made up of multiple subfields that are thought to reflect V1 inputs and are capable of encoding the spatial relationship between local stimulus features. We created primate models of anisometropic amblyopia and analyzed the RF subfield maps for multiple nearby V2 neurons of anesthetized monkeys by using dynamic two-dimensional noise stimuli and reverse correlation methods. Unlike in normal monkeys, the subfield maps of V2 neurons in amblyopic monkeys were severely disorganized: subfield maps showed higher heterogeneity within each neuron as well as across nearby neurons. Amblyopic V2 neurons exhibited robust binocular suppression and the strength of the suppression was positively correlated with the degree of hereogeneity and the severity of amblyopia in individual monkeys. Our results suggest that the disorganized subfield maps and robust binocular suppression of amblyopic V2 neurons are likely to adversely affect the higher stages of cortical processing resulting in position uncertainty and image distortion.
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19
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Laramée ME, Boire D. Visual cortical areas of the mouse: comparison of parcellation and network structure with primates. Front Neural Circuits 2015; 8:149. [PMID: 25620914 PMCID: PMC4286719 DOI: 10.3389/fncir.2014.00149] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Accepted: 12/09/2014] [Indexed: 12/27/2022] Open
Abstract
Brains have evolved to optimize sensory processing. In primates, complex cognitive tasks must be executed and evolution led to the development of large brains with many cortical areas. Rodents do not accomplish cognitive tasks of the same level of complexity as primates and remain with small brains both in relative and absolute terms. But is a small brain necessarily a simple brain? In this review, several aspects of the visual cortical networks have been compared between rodents and primates. The visual system has been used as a model to evaluate the level of complexity of the cortical circuits at the anatomical and functional levels. The evolutionary constraints are first presented in order to appreciate the rules for the development of the brain and its underlying circuits. The organization of sensory pathways, with their parallel and cross-modal circuits, is also examined. Other features of brain networks, often considered as imposing constraints on the development of underlying circuitry, are also discussed and their effect on the complexity of the mouse and primate brain are inspected. In this review, we discuss the common features of cortical circuits in mice and primates and see how these can be useful in understanding visual processing in these animals.
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Affiliation(s)
- Marie-Eve Laramée
- Laboratory of Neuroplasticity and Neuroproteomics, Department of Biology, KU Leuven-University of Leuven Leuven, Belgium
| | - Denis Boire
- Département d'anatomie, Université du Québec à Trois-Rivières Trois-Rivières, QC, Canada
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20
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Adams DL, Piserchia V, Economides JR, Horton JC. Vascular Supply of the Cerebral Cortex is Specialized for Cell Layers but Not Columns. Cereb Cortex 2014; 25:3673-81. [PMID: 25246513 DOI: 10.1093/cercor/bhu221] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The vascular supply to layers and columns was compared in macaque primary visual cortex (V1) by labeling red blood cells via their endogenous peroxidase activity. Alternate sections were processed for cytochrome oxidase to reveal "patches" or "blobs," which anchor the interdigitated column systems of striate cortex. More densely populated cell layers received the most profuse blood supply. In the superficial layers the blood supply was organized into microvascular lobules, consisting of a central venule surrounded by arterioles. Each vessel was identified as an arteriole or venule by matching it with the penetration site where it entered the cortex from a parent arteriole or venule in the pial circulation. Although microvascular lobules and cytochrome oxidase patches had a similar periodicity, they bore no mutual relationship. The size and density of penetrating arterioles and venules did not differ between patches and interpatches. The red blood cell labeling in patches and interpatches was equal. Moreover, patches and interpatches were supplied by an anastomotic pial arteriole system, with no segregation of blood supply to the two compartments. Often a focal constriction was present at the origin of pial arterial branches, indicating that local control of cortical perfusion may be accomplished by vascular sphincters.
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Affiliation(s)
- Daniel L Adams
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143, USA Center for Mind/Brain Sciences, The University of Trento, Trento, Italy
| | | | - John R Economides
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Jonathan C Horton
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143, USA
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21
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Misbinding of color and motion in human visual cortex. Curr Biol 2014; 24:1354-1360. [PMID: 24856212 DOI: 10.1016/j.cub.2014.04.045] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 04/09/2014] [Accepted: 04/22/2014] [Indexed: 11/21/2022]
Abstract
A fundamental challenge for the visual system is to integrate visual features into a coherent scene, known as the binding problem. The neural mechanisms of feature binding are hard to identify because of difficulties in separating active feature binding from feature co-occurrence. In previous studies on feature binding, visual features were superimposed and presented simultaneously. Neurons throughout the visual cortex are known to code multiple features. Therefore, the observed binding effects could be due to the physical co-occurrence of features and the sensory representation of feature pairings. It is uncertain whether the mechanisms responsible for perceptual binding were actually recruited. To address this issue, we performed psychophysical and fMRI experiments to investigate the neural mechanisms of a steady-state misbinding of color and motion, because feature misbinding is probably the most striking evidence for the active existence of the binding mechanisms. We found that adapting to the color-motion misbinding generated the color-contingent motion aftereffect, as well as the color-contingent motion adaptation effect in visual cortex. Notably, V2 exhibited the strongest adaptation effect, which significantly correlated with the aftereffect across subjects. Furthermore, effective connectivity analysis using dynamic causal modeling showed that the misbinding was closely associated with enhanced feedback from V4 and V5 to V2. These findings provide strong evidence for active feature binding in early visual cortex and suggest a critical role of reentrant connections from specialized intermediate areas to early visual cortex in this process.
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22
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Breitmeyer BG. Contributions of magno- and parvocellular channels to conscious and non-conscious vision. Philos Trans R Soc Lond B Biol Sci 2014; 369:20130213. [PMID: 24639584 DOI: 10.1098/rstb.2013.0213] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The dorsal and ventral cortical pathways, driven predominantly by magnocellular (M) and parvocellular (P) inputs, respectively, assume leading roles in models of visual information processing. Although in prior proposals, the dorsal and ventral pathways support non-conscious and conscious vision, respectively, recent modelling and empirical developments indicate that each pathway plays important roles in both non-conscious and conscious vision. In these models, the ventral P-pathway consists of one subpathway processing an object's contour features, e.g. curvature, the other processing its surface attributes, e.g. colour. Masked priming studies have shown that feed-forward activity in the ventral P-pathway on its own supports non-conscious processing of contour and surface features. The dorsal M-pathway activity contributes directly to conscious vision of motion and indirectly to object vision by projecting to prefrontal cortex, which in turn injects top-down neural activity into the ventral P-pathway and there 'ignites' feed-forward-re-entrant loops deemed necessary for conscious vision. Moreover, an object's shape or contour remains invisible without the prior conscious registration of its surface properties, which for that reason are taken to comprise fundamental visual qualia. Besides suggesting avenues for future research, these developments bear on several recent and past philosophical issues.
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Affiliation(s)
- Bruno G Breitmeyer
- Department of Psychology and Center for Neuro-Engineering and Cognitive Science, University of Houston, , Houston, TX 77204-5022, USA
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23
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Abstract
In this paper, we review the path taken by signals originating from the short wavelength sensitive cones (S-cones) in Old World and New World primates. Two types of retinal ganglion cells (RGCs) carrying S-cone signals (blue-On and blue-Off cells) project to the dorsal lateral geniculate nucleus (dLGN) in the thalamus. In all primates, these S-cone signals are relayed through the 'dust-like' (konis in classical Greek) dLGN cells. In New World primates such as common marmoset, these very small cells are known to form distinct and spatially extensive, koniocellular layers. Although in Old World primates, such as macaques, koniocellular layers tend to be very thin, the adjacent parvocellular layers contain distinct koniocellular extensions. It appears that all S-cone signals are relayed through such konio cells, whether they are in the main koniocellular layers or in their colonies within the parvocellular layers of the dLGN. In the primary visual cortex, these signals begin to merge with the signals carried by the other two principal parallel channels, namely the magnocellular and parvocellular channels. This article will also review the possible routes taken by the S-cone signals to reach one of the topographically organised extrastriate visual cortical areas, the middle temporal area (area MT). This area is the major conduit for signals reaching the parietal cortex. Alternative visual inputs to area MT not relayed via the primary visual cortex area (V1) may provide the neurological basis for the phenomenon of 'blindsight' observed in human and non-human primates, who have partial or complete damage to the primary visual cortex. Short wavelength sensitive cone (S-cone) signals to area MT may also play a role in directing visual attention with possible implications for understanding the pathology in dyslexia and some of its treatment options.
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Affiliation(s)
- Jaikishan Jayakumar
- Department of Optometry & Vision Sciences and Melbourne Brain Centre, The University of Melbourne, Parkville, Victoria, Australia
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Baldwin MKL, Kaskan PM, Zhang B, Chino YM, Kaas JH. Cortical and subcortical connections of V1 and V2 in early postnatal macaque monkeys. J Comp Neurol 2012; 520:544-69. [PMID: 21800316 DOI: 10.1002/cne.22732] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Connections of primary (V1) and secondary (V2) visual areas were revealed in macaque monkeys ranging in age from 2 to 16 weeks by injecting small amounts of cholera toxin subunit B (CTB). Cortex was flattened and cut parallel to the surface to reveal injection sites, patterns of labeled cells, and patterns of cytochrome oxidase (CO) staining. Projections from the lateral geniculate nucleus and pulvinar to V1 were present at 4 weeks of age, as were pulvinar projections to thin and thick CO stripes in V2. Injections into V1 in 4- and 8-week-old monkeys labeled neurons in V2, V3, middle temporal area (MT), and dorsolateral area (DL)/V4. Within V1 and V2, labeled neurons were densely distributed around the injection sites, but formed patches at distances away from injection sites. Injections into V2 labeled neurons in V1, V3, DL/V4, and MT of monkeys 2-, 4-, and 8-weeks of age. Injections in thin stripes of V2 preferentially labeled neurons in other V2 thin stripes and neurons in the CO blob regions of V1. A likely thick stripe injection in V2 at 4 weeks of age labeled neurons around blobs. Most labeled neurons in V1 were in superficial cortical layers after V2 injections, and in deep layers of other areas. Although these features of adult V1 and V2 connectivity were in place as early as 2 postnatal weeks, labeled cells in V1 and V2 became more restricted to preferred CO compartments after 2 weeks of age.
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Affiliation(s)
- Mary K L Baldwin
- Department of Psychology, Vanderbilt University, Nashville Tennessee 37212, USA
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25
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Abstract
The mechanism of amblyopia in children with congenital cataract is not understood fully, but studies in macaques have shown that geniculate synapses are lost in striate cortex (V1). To search for other projection abnormalities in amblyopia, the pathway from V1 to V2 was examined using a triple-label technique in three animals raised with monocular suture. [(3)H]proline was injected into one eye to label the ocular dominance columns. Cholera toxin B subunit conjugated to gold (CTB-Au) was injected into V2 to label V1 projection neurons. Alternate sections were processed for cytochrome oxidase (CO) and CTB-Au, or dipped for autoradiography. Eight fields of CTB-Au-labeled cells in V1 opposite injection sites were plotted in layers 2/3 or 4B. After thin stripe injection, labeled cells were concentrated in CO patches. Despite column shrinkage, cells in deprived and normal columns were equal in size and density in both layers 2/3 and 4B. After pale or thick stripe injection, labeled cells were concentrated in interpatches. Only 23% of projection neurons originated from deprived columns. This reduction exceeded the degree of column shrinkage, a result explained by the fact that column shrinkage causes disproportionate loss of interpatch territory. These data indicate that early monocular form deprivation does not alter the segregation of patch and interpatch pathways to V2 stripes or cause selective loss or atrophy of V1 projection neurons. The effect of shrinkage of geniculocortical afferents in layer 4C following visual deprivation is not amplified further by attenuation of the amblyopic eye's projections from V1 to V2.
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Breitmeyer BG, Tapia E. Roles of contour and surface processing in microgenesis of object perception and visual consciousness. Adv Cogn Psychol 2011; 7:68-81. [PMID: 22253670 PMCID: PMC3259033 DOI: 10.2478/v10053-008-0088-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Accepted: 06/07/2011] [Indexed: 11/20/2022] Open
Abstract
Developments in visual neuroscience and neural-network modeling indicate the existence of separate pathways for the processing of form and surface attributes of a visual object. In line with prior theoretical proposals, it is assumed that the processing of form can be explicit or conscious only as or after the surface property such as color is filled in. In conjunction with extant psychophysical findings, these developments point to interesting distinctions between nonconscious and conscious processing of these attributes, specifically in relation to distinguishable temporal dynamics. At nonconscious levels form processing proceeds faster than surface processing, whereas in contrast, at conscious levels form processing proceeds slower than surface processing. I mplications of separate form and surface processing for current and future psychophysical and neuroscientific research, particularly that relating cortical oscillations to conjunctions of surface and form features, and for cognitive science and philosophy of mind and consciousness are discussed.
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Affiliation(s)
| | - Evelina Tapia
- Center for Neuro-Engineering and Cognitive Science, University of
Houston, Houston, TX, USA
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Orientation tuning of cytochrome oxidase patches in macaque primary visual cortex. Nat Neurosci 2011; 14:1574-80. [PMID: 22057193 PMCID: PMC3332086 DOI: 10.1038/nn.2958] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Accepted: 09/12/2011] [Indexed: 11/08/2022]
Abstract
The abundant concentration of cytochrome oxidase in patches or blobs of primate striate cortex has never been explained. Patches are thought to contain unoriented, color-opponent neurons. Lacking orientation selectivity, these cells might endow patches with high metabolic activity because they respond to all contours in visual scenes. To test this idea, we measured orientation tuning in layer 2/3 of macaque cortical area V1 using acutely implanted 100-electrode arrays. Each electrode recording site was identified and assigned to the patch or interpatch compartment. The mean orientation bandwidth of cells was 28.4° in patches and 25.8° in interpatches. Neurons in patches were indeed less orientation selective, but the difference was subtle, indicating that the processing of form and color is not strictly segregated in V1. The most conspicuous finding was that patch cells had a 49% greater overall firing rate. This global difference in neuronal responsiveness, rather than an absence of orientation tuning, may account for the rich mitochondrial enzyme activity that defines patches.
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Ninomiya T, Sawamura H, Inoue KI, Takada M. Differential architecture of multisynaptic geniculo-cortical pathways to V4 and MT. ACTA ACUST UNITED AC 2011; 21:2797-808. [PMID: 21515714 DOI: 10.1093/cercor/bhr078] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Parallel visual pathways in the primate brain known as the dorsal and ventral streams receive retinal inputs mainly through the magnocellular (M) and parvocellular (P) layers of the lateral geniculate nucleus. Inputs from these layers terminate within distinct parts of layer 4C of V1 (visual area 1). Due to the complexity of M- and P-derived neural connectivity in V1 and higher visual areas, the contributions of M and P inputs to the dorsal and ventral streams remain unclear. Employing retrograde transsynaptic transport of rabies virus, we analyzed the architecture of bottom-up pathways toward ventral stream area V4 (visual area 4) and dorsal stream area MT (middle temporal area). We found that V4 receives both M and P inputs "trisynaptically" from layer 4C via layer 2/3 of V1, whereas MT receives M-dominant input "disynaptically" from layer 4C via layer 4B of V1. V4 also receives disynaptic input from the dorsal stream portion of V2 (visual area 2) (i.e., cytochrome oxidase-stained thick stripes). Moreover, both M and P inputs reach V4 trisynaptically and MT disynaptically through "short-cut" pathways that bypass layer 4C of V1. The differential patterns of multisynaptic geniculo-cortical pathways to V4 and MT imply distinct modes of information processing in the dorsal and ventral streams.
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Affiliation(s)
- Taihei Ninomiya
- Department of System Neuroscience, Tokyo Metropolitan Institute for Neuroscience, Fuchu, Tokyo 183-8526, Japan
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Abstract
Cytochrome oxidase (CO) reveals two compartments in V1 (patches and interpatches) and three compartments in V2 (thin, pale, and thick stripes). Previously, it was shown that thin stripes receive input predominantly from patches. Here we examined the projections to thick and pale stripes in macaques, revealed by retrograde tracer injections. After thick stripe injection, cells were distributed in layer 2/3 (67%), layer 4A (7%), layer 4B (23%), and layer 5/6 (2%). Except in layer 5/6, cells were concentrated in interpatches, with a stronger bias in layer 2/3 (84%) than in layer 4B (75%). After pale stripe injection, cells were found in layer 2/3 (87%), layer 4A (2%), layer 4B (10%), and layer 5/6 (2%). As for thick stripes, cells were located preferentially in interpatches in layer 2/3 (84%) and layer 4B (72%) but not in layer 5/6. Thick stripes received a higher proportion of their input from layer 4B, compared with pale stripes, consistent with reports that thick stripe neurons exhibit a pronounced layer 4B influence. This difference aside, both stripe types receive similar inputs from V1, at least in terms of cortical layer and CO compartment. This finding was bolstered by injecting different tracers into pale and thick stripes; 10-27% of cells were double labeled, with most located in interpatches. These results suggest that the distinctive receptive field properties of neurons in thick and pale stripes are generated by local V2 circuits, or by other specific projections, rather than by differing sources of laminar and compartmental input from V1.
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Abstract
In the primate visual system, areas V1 and V2 distribute information they receive from the retina to all higher cortical areas, sorting this information into dorsal and ventral streams. Therefore, knowledge of the organization of projections between V1 and V2 is crucial to understand how the cortex processes visual information. In primates, parallel output pathways from V1 project to distinct V2 stripes. The traditional tripartite division of V1-to-V2 projections was recently replaced by a bipartite scheme, in which thin stripes receive V1 inputs from blob columns, and thick and pale stripes receive common input from interblob columns. Here, we demonstrate that thick and pale stripes, instead, receive spatially segregated V1 inputs and that the interblob is partitioned into two compartments: the middle of the interblob projecting to pale stripes and the blob/interblob border region projecting to thick stripes. Double-labeling experiments further demonstrate that V1 cells project to either thick or pale stripes, but rarely to both. We also find laminar specialization of V1 outputs, with layer 4B contributing projections mainly to thick stripes, and no projections to one set of pale stripes. These laminar differences suggest different contribution of magno, parvo, and konio inputs to each V1 output pathway. These results provide a new foundation for parallel processing models of the visual system by demonstrating four V1-to-V2 pathways: blob columns-to-thin stripes, blob/interblob border columns-to-thick stripes, interblob columns-to-pale(lateral) stripes, layer 2/3-4A interblobs-to-pale(medial) stripes.
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The synaptic connections between cortical areas V1 and V2 in macaque monkey. J Neurosci 2009; 29:11283-93. [PMID: 19741135 DOI: 10.1523/jneurosci.5757-08.2009] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The primary visual cortex (V1) and V2 together form approximately 24% of the total neocortex of the macaque monkey and have each other as their major partners. The major target of the V1 projection to V2 is layer 4, where it forms clusters of boutons, which form asymmetric (excitatory) synapses mainly with dendritic spines (75%). The remainder form synapses with dendritic shafts. The synapses found on spines were often more complex, perforated postsynaptic densities than those found on dendritic shafts. The reciprocal projection from V2 to V1 targeted layers 1, 2/3, and 5 and was formed of axons of different morphologies. One axon type, originating from superficial layer pyramidal cells, had a morphology resembling those of local pyramidal cell collaterals. These axons arborized in layers 1, 2/3, and 5 of V1. Another type of axon, arborizing in layer 1, was slender (0.3 microm), unbranched, unmyelinated, and uniformly covered with boutons terminaux and formed asymmetric synapses mainly with slender spines. Yet a third type of axon also confined to layer 1, was thick (>1 microm), branched, heavily myelinated, and formed separate small clusters of large ( approximately 1 microm) en passant multisynaptic boutons that formed asymmetric synapses mainly with large flat spines. These data show the existence of a reciprocal excitatory loop between V1 and V2 that is formed by different axonal types, each with preferred layers of termination.
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Lim H, Wang Y, Xiao Y, Hu M, Felleman DJ. Organization of hue selectivity in macaque V2 thin stripes. J Neurophysiol 2009; 102:2603-15. [PMID: 19571184 DOI: 10.1152/jn.91255.2008] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
V2 has long been recognized to contain functionally distinguishable compartments that are correlated with the stripelike pattern of cytochrome oxidase activity. Early electrophysiological studies suggested that color, direction/disparity, and orientation selectivity were largely segregated in the thin, thick, and interstripes, respectively. Subsequent studies revealed a greater degree of homogeneity in the distribution of response properties across stripes, yet color-selective cells were still found to be most prevalent in the thin stripes. Optical recording studies have demonstrated that thin stripes contain both color-preferring and luminance-preferring modules. These thin stripe color-preferring modules contain spatially organized hue maps, whereas the luminance-preferring modules contain spatially organized luminance-change maps. In this study, the neuronal basis of these hue maps was determined by characterizing the selectivity of neurons for isoluminant hues in multiple penetrations within previously characterized V2 thin stripe hue maps. The results indicate that neurons within the superficial layers of V2 thin stripe hue maps are organized into columns whose aggregated hue selectivity is closely related to the hue selectivity of the optically defined hue maps. These data suggest that thin stripes contain hue maps not simply because of their moderate percentage of hue-selective neurons, but because of the columnar and tangential organization of hue selectivity.
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Affiliation(s)
- Heejin Lim
- Department of Neurobiology and Anatomy, University of Texas Medical School-Houston, Houston, TX 77030, USA
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Abstract
In some mammalian species, geniculocortical afferents serving each eye are segregated in layer 4C of striate cortex into stripes called ocular dominance columns. Having described the complete pattern of ocular dominance columns in the human brain, the authors enumerate here the principal enigmas that confront future investigators. Probably the overarching challenge is to explain the function, if any, of ocular dominance columns and why they are present in some species and not others. A satisfactory solution must account for the enormous natural variation, even within the same species, among individuals in column expression, pattern, periodicity, and alignment with other components of the functional architecture. Another major priority is to explain the development of ocular dominance columns. It has been established clearly that they form without visual experience, but the innate signals that guide their segregation and maturation are unknown. Experiments addressing the role of spontaneous retinal activity have yielded contradictory data. These studies must be reconciled, to pave the way for new insights into how columnar structure is generated in the cerebral cortex.
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Affiliation(s)
- Daniel L Adams
- Department of Cognitive Science, Center for Mind/Brain Sciences, University of Trento, Italy
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Seymour K, Clifford CW, Logothetis NK, Bartels A. The Coding of Color, Motion, and Their Conjunction in the Human Visual Cortex. Curr Biol 2009; 19:177-83. [PMID: 19185496 DOI: 10.1016/j.cub.2008.12.050] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2008] [Revised: 11/18/2008] [Accepted: 12/10/2008] [Indexed: 11/25/2022]
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Functional organization of color domains in V1 and V2 of macaque monkey revealed by optical imaging. Cereb Cortex 2007; 18:516-33. [PMID: 17576751 DOI: 10.1093/cercor/bhm081] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Areas V1 and V2 of Macaque monkey visual cortex are characterized by unique cytochrome-oxidase (CO)-staining patterns. Initial electrophysiological studies associated CO blobs in V1 with processing of surface properties such as color and brightness and the interblobs with contour information processing. However, many subsequent studies showed controversial results, some supporting this proposal and others failing to find significant functional differences between blobs and interblobs. In this study, we have used optical imaging to map color-selective responses in V1 and V2. In V1, we find striking "blob-like" patterns of color response. Fine alignment of optical maps and CO-stained tissue revealed that color domains in V1 strongly associate with CO blobs. We also find color domains in V1 align along centers of ocular dominance columns. Furthermore, color blobs in V1 have low orientation selectivity and do not overlap with centers of orientation domains. In V2, color domains coincide with thin stripes; orientation-selective domains coincide with thick and pale stripes. We conclude that color and orientation-selective responses are preferentially located in distinct CO compartments in V1 and V2. We propose that the term "blob" encompasses both the concept of "CO blob" and "color domain" in V1.
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Xiao Y, Casti A, Xiao J, Kaplan E. Hue maps in primate striate cortex. Neuroimage 2006; 35:771-86. [PMID: 17276087 PMCID: PMC1892586 DOI: 10.1016/j.neuroimage.2006.11.059] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2006] [Revised: 11/10/2006] [Accepted: 11/15/2006] [Indexed: 11/28/2022] Open
Abstract
The macaque striate cortex (V1) contains neurons that respond preferentially to various hues. The properties of these hue-selective neurons have been studied extensively at the single-unit level, but it is unclear how stimulus hue is represented by the distribution of activity across neuronal populations in V1. Here we use the intrinsic optical signal to image V1 responses to spatially uniform stimuli of various hues. We found that (1) each of these stimuli activates an array of patches in the supragranular layers of the parafoveal V1; (2) the patches activated by different hues overlapped partially; 3) the peak locations of these patches were determined by stimulus hue. The peaks associated with various hues form well-separated clusters, in which nearby peaks represent perceptually similar hues. Each cluster represents a full gamut of hue in a small cortical area ( approximately 160 microm long). The hue order is preserved within each peak cluster, but the clusters have various geometrical shapes. These clusters were co-localized with regions that responded preferentially to chromatic gratings compared with achromatic ones. Our results suggest that V1 contains an array of hue maps, in which the hue of a stimulus is represented by the location of the peak response to the stimulus. The orderly, organized hue maps in V1, together with the recently discovered hue maps in the extrastriate cortical area V2, are likely to play an important role in hue perception in primates.
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Affiliation(s)
- Youping Xiao
- Department of Neuroscience, Mail box 1065, Mount Sinai School of Medicine, 1 Gustave L. Levy Place, New York, NY 10029, USA.
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Bartels A, Zeki S. The temporal order of binding visual attributes. Vision Res 2006; 46:2280-6. [PMID: 16387344 DOI: 10.1016/j.visres.2005.11.017] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2005] [Revised: 11/08/2005] [Accepted: 11/10/2005] [Indexed: 11/21/2022]
Abstract
The brain processes distinct attributes such as colour and motion in anatomically largely segregated systems. Moreover, these two attributes are perceived with different latencies. Here, we show that the time required to bind these two attributes differs too. In psychophysical experiments, we determined minimal presentation times required to perceptually pair spatially separate pairs of stimuli consisting of colour or motion. Binding two colours required longer presentation times than binding the directions of two moving stimuli. Cross-attribute binding between colour and motion took longer than within-attribute binding. This was so even when the relative perceptual delay between colour and motion was compensated for, which accelerated colour-motion binding. Moreover, stimuli could be discriminated but not bound at fast presentation rates. Our results thus show that spatial binding is an attribute-specific process and faster within the same than across different attributes. Furthermore, the time required to bind attributes is independent of that required to process them, since colour is perceived before motion but requires longer time for binding. Finally, our results suggest that binding acts on attribute-specific neural representations of the stimuli at a late, perceptually explicit stage. These results lead us to conclude that spatial binding is separate from, and subsequent to, stimulus processing and that it is an attribute-dependent and post-conscious process.
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Affiliation(s)
- A Bartels
- Laboratory of Neurobiology, Department of Anatomy, University College London, London WC1E 6BT, UK
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