1
|
van Leeuwen JEP, McDougall A, Mylonas D, Suárez-González A, Crutch SJ, Warren JD. Pupil responses to colorfulness are selectively reduced in healthy older adults. Sci Rep 2023; 13:22139. [PMID: 38092848 PMCID: PMC10719259 DOI: 10.1038/s41598-023-48513-7] [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: 06/28/2023] [Accepted: 11/27/2023] [Indexed: 12/17/2023] Open
Abstract
The alignment between visual pathway signaling and pupil dynamics offers a promising non-invasive method to further illuminate the mechanisms of human color perception. However, only limited research has been done in this area and the effects of healthy aging on pupil responses to the different color components have not been studied yet. Here we aim to address this by modelling the effects of color lightness and chroma (colorfulness) on pupil responses in young and older adults, in a closely controlled passive viewing experiment with 26 broad-spectrum digital color fields. We show that pupil responses to color lightness and chroma are independent from each other in both young and older adults. Pupil responses to color lightness levels are unaffected by healthy aging, when correcting for smaller baseline pupil sizes in older adults. Older adults exhibit weaker pupil responses to chroma increases, predominantly along the Green-Magenta axis, while relatively sparing the Blue-Yellow axis. Our findings complement behavioral studies in providing physiological evidence that colors fade with age, with implications for color-based applications and interventions both in healthy aging and later-life neurodegenerative disorders.
Collapse
Affiliation(s)
- Janneke E P van Leeuwen
- Dementia Research Centre, UCL Queen Square Institute of Neurology, University College London, 8-11 Queen Square, London, WC1N 3AR, UK.
- The Thinking Eye, ACAVA Limehouse Arts Foundation, London, UK.
| | - Amy McDougall
- Department of Medical Statistics, London School of Hygiene & Tropical Medicine, London, UK
| | - Dimitris Mylonas
- Faculty of Philosophy, Northeastern University London, London, UK
| | - Aida Suárez-González
- Dementia Research Centre, UCL Queen Square Institute of Neurology, University College London, 8-11 Queen Square, London, WC1N 3AR, UK
| | - Sebastian J Crutch
- Dementia Research Centre, UCL Queen Square Institute of Neurology, University College London, 8-11 Queen Square, London, WC1N 3AR, UK
| | - Jason D Warren
- Dementia Research Centre, UCL Queen Square Institute of Neurology, University College London, 8-11 Queen Square, London, WC1N 3AR, UK.
| |
Collapse
|
2
|
Bevilacqua M, Huxlin KR, Hummel FC, Raffin E. Pathway and directional specificity of Hebbian plasticity in the cortical visual motion processing network. iScience 2023; 26:107064. [PMID: 37408682 PMCID: PMC10319215 DOI: 10.1016/j.isci.2023.107064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 02/14/2023] [Accepted: 06/02/2023] [Indexed: 07/07/2023] Open
Abstract
Cortico-cortical paired associative stimulation (ccPAS), which repeatedly pairs single-pulse transcranial magnetic stimulation (TMS) over two distant brain regions, is thought to modulate synaptic plasticity. We explored its spatial selectivity (pathway and direction specificity) and its nature (oscillatory signature and perceptual consequences) when applied along the ascending (Forward) and descending (Backward) motion discrimination pathway. We found unspecific connectivity increases in bottom-up inputs in the low gamma band, probably reflecting visual task exposure. A clear distinction in information transfer occurred in the re-entrant alpha signals, which were only modulated by Backward-ccPAS, and predictive of visual improvements in healthy participants. These results suggest a causal involvement of the re-entrant MT-to-V1 low-frequency inputs in motion discrimination and integration in healthy participants. Modulating re-entrant input activity could provide single-subject prediction scenarios for visual recovery. Visual recovery might indeed partly rely on these residual inputs projecting to spared V1 neurons.
Collapse
Affiliation(s)
- Michele Bevilacqua
- Defitech Chair in Clinical Neuroengineering, Neuro-X Institute (NRX) and Brain Mind Institute, EPFL, Geneva, Switzerland
- Defitech Chair in Clinical Neuroengineering, Neuro-X Institute (NRX) and Brain Mind Institute, Clinique Romande de Readaptation (CRR), EPFL Valais, Sion, Switzerland
| | - Krystel R. Huxlin
- The Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, NY, USA
| | - Friedhelm C. Hummel
- Defitech Chair in Clinical Neuroengineering, Neuro-X Institute (NRX) and Brain Mind Institute, EPFL, Geneva, Switzerland
- Defitech Chair in Clinical Neuroengineering, Neuro-X Institute (NRX) and Brain Mind Institute, Clinique Romande de Readaptation (CRR), EPFL Valais, Sion, Switzerland
- Clinical Neuroscience, University of Geneva Medical School, Geneva, Switzerland
| | - Estelle Raffin
- Defitech Chair in Clinical Neuroengineering, Neuro-X Institute (NRX) and Brain Mind Institute, EPFL, Geneva, Switzerland
- Defitech Chair in Clinical Neuroengineering, Neuro-X Institute (NRX) and Brain Mind Institute, Clinique Romande de Readaptation (CRR), EPFL Valais, Sion, Switzerland
| |
Collapse
|
3
|
Functionally specific and sparse domain-based micro-networks in monkey V1 and V2. Curr Biol 2022; 32:2797-2809.e3. [PMID: 35623347 DOI: 10.1016/j.cub.2022.04.095] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/05/2022] [Accepted: 04/28/2022] [Indexed: 11/23/2022]
Abstract
The cerebral cortices of human and nonhuman primate brains are characterized by submillimeter functional domains. However, little is known about the connections of single functional domains. Here, in macaque monkey visual cortex, we have developed a targeted focal electrical stimulation method, coupled with functional optical imaging, to map cortical networks with submillimeter precision in vivo. We find that single functional domains are a part of highly specific and sparse intra-areal and inter-areal micro-networks. Across color-related and orientation-related functionalities, these micro-networks exhibit parallel connection patterns, suggesting a common domain-based architecture. Moreover, these micro-networks shift topographically at a submillimeter scale, suggesting that they serve as a fundamental unit for cortical information processing. Our findings establish a domain-based connectional architecture in the primate brain and present new constraints for cortical map representation.
Collapse
|
4
|
Meikle SJ, Wong YT. Neurophysiological considerations for visual implants. Brain Struct Funct 2021; 227:1523-1543. [PMID: 34773502 DOI: 10.1007/s00429-021-02417-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 10/17/2021] [Indexed: 11/26/2022]
Abstract
Neural implants have the potential to restore visual capabilities in blind individuals by electrically stimulating the neurons of the visual system. This stimulation can produce visual percepts known as phosphenes. The ideal location of electrical stimulation for achieving vision restoration is widely debated and dependent on the physiological properties of the targeted tissue. Here, the neurophysiology of several potential target structures within the visual system will be explored regarding their benefits and downfalls in producing phosphenes. These regions will include the lateral geniculate nucleus, primary visual cortex, visual area 2, visual area 3, visual area 4 and the middle temporal area. Based on the existing engineering limitations of neural prostheses, we anticipate that electrical stimulation of any singular brain region will be incapable of achieving high-resolution naturalistic perception including color, texture, shape and motion. As improvements in visual acuity facilitate improvements in quality of life, emulating naturalistic vision should be one of the ultimate goals of visual prostheses. To achieve this goal, we propose that multiple brain areas will need to be targeted in unison enabling different aspects of vision to be recreated.
Collapse
Affiliation(s)
- Sabrina J Meikle
- Department of Electrical and Computer Systems Engineering, Monash University, 14 Alliance Lane, Clayton, Vic, 3800, Australia
- Department of Physiology and Biomedicine Discovery Institute, Monash University, 14 Alliance Lane, Clayton, Vic, 3800, Australia
- Monash Vision Group, Monash University, 14 Alliance Lane, Clayton, Vic, 3800, Australia
| | - Yan T Wong
- Department of Electrical and Computer Systems Engineering, Monash University, 14 Alliance Lane, Clayton, Vic, 3800, Australia.
- Department of Physiology and Biomedicine Discovery Institute, Monash University, 14 Alliance Lane, Clayton, Vic, 3800, Australia.
- Monash Vision Group, Monash University, 14 Alliance Lane, Clayton, Vic, 3800, Australia.
| |
Collapse
|
5
|
Using perceptual tasks to selectively measure magnocellular and parvocellular performance: Rationale and a user's guide. Psychon Bull Rev 2021; 28:1029-1050. [PMID: 33742424 PMCID: PMC8367893 DOI: 10.3758/s13423-020-01874-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/26/2020] [Indexed: 11/24/2022]
Abstract
The visual system uses parallel pathways to process information. However, an ongoing debate centers on the extent to which the pathways from the retina, via the Lateral Geniculate nucleus to the visual cortex, process distinct aspects of the visual scene and, if they do, can stimuli in the laboratory be used to selectively drive them. These questions are important for a number of reasons, including that some pathologies are thought to be associated with impaired functioning of one of these pathways and certain cognitive functions have been preferentially linked to specific pathways. Here we examine the two main pathways that have been the focus of this debate: the magnocellular and parvocellular pathways. Specifically, we review the results of electrophysiological and lesion studies that have investigated their properties and conclude that while there is substantial overlap in the type of information that they process, it is possible to identify aspects of visual information that are predominantly processed by either the magnocellular or parvocellular pathway. We then discuss the types of visual stimuli that can be used to preferentially drive these pathways.
Collapse
|
6
|
Navarro KT, Sanchez MJ, Engel SA, Olman CA, Weldon KB. Depth-dependent functional MRI responses to chromatic and achromatic stimuli throughout V1 and V2. Neuroimage 2020; 226:117520. [PMID: 33137474 PMCID: PMC7958868 DOI: 10.1016/j.neuroimage.2020.117520] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 10/21/2020] [Accepted: 10/26/2020] [Indexed: 11/13/2022] Open
Abstract
In the primate visual system, form (shape, location) and color information are processed in separate but interacting pathways. Recent access to high-resolution neuroimaging has facilitated the exploration of the structure of these pathways at the mesoscopic level in the human visual cortex. We used 7T fMRI to observe selective activation of the primary visual cortex to chromatic versus achromatic stimuli in five participants across two scanning sessions. Achromatic checkerboards with low spatial frequency and high temporal frequency targeted the color-insensitive magnocellular pathway. Chromatic checkerboards with higher spatial frequency and low temporal frequency targeted the color-selective parvocellular pathway. This work resulted in three main findings. First, responses driven by chromatic stimuli had a laminar profile biased towards superficial layers of V1, as compared to responses driven by achromatic stimuli. Second, we found stronger preference for chromatic stimuli in parafoveal V1 compared with peripheral V1. Finally, we found alternating, stimulus-selective bands stemming from the V1 border into V2 and V3. Similar alternating patterns have been previously found in both NHP and human extrastriate cortex. Together, our findings confirm the utility of fMRI for revealing details of mesoscopic neural architecture in human cortex.
Collapse
Affiliation(s)
- Karen T Navarro
- Department of Psychology, University of Minnesota, 75 E River Rd, Minneapolis, MN 55455, United States.
| | - Marisa J Sanchez
- Department of Psychiatry and Behavioral Sciences, University of Minnesota, 2450 Riverside Ave f275, Minneapolis, MN 55454, United States
| | - Stephen A Engel
- Department of Psychology, University of Minnesota, 75 E River Rd, Minneapolis, MN 55455, United States
| | - Cheryl A Olman
- Department of Psychology, University of Minnesota, 75 E River Rd, Minneapolis, MN 55455, United States; Center for Magnetic Resonance Research, University of Minnesota, 2021 6th St SE, Minneapolis, MN 55455, United States
| | - Kimberly B Weldon
- Department of Psychiatry and Behavioral Sciences, University of Minnesota, 2450 Riverside Ave f275, Minneapolis, MN 55454, United States; Center for Magnetic Resonance Research, University of Minnesota, 2021 6th St SE, Minneapolis, MN 55455, United States
| |
Collapse
|
7
|
Theoretical Implications on Visual (Color) Representation and Cytochrome Oxidase Blobs. ACTA ACUST UNITED AC 2017. [DOI: 10.1007/bf03379594] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Abstract
The rich concentration of mitochondrial cytochrome oxidase (CO) blobs in the V1 (striate) primate visual cortex has never been explained. Although the distribution of CO blobs provided a persuasive example of columnar structure in the V1, there are contradictions about the existence of hypercolumns. Since photoreceptors and other retinal cells process and convey basically external visible photonic signals, it suggests that one of the most important tasks of early visual areas is to represent these external visible color photonic signals during visual perception. This representation may occur essentially in CO-rich blobs of the V1. Here we suggest that the representation of external visible photon signals (i.e. visual representation) can be the most energetic allocation process in the brain, which is reasonably performed by the highest density neuron al V1 areas and mitochondrial-rich cytochrome oxidases. It is also raised that the functional unit for phosphene induction can be linked to small clusters of Co —rich blobs in V1. We present some implications about distinction between the physics of visible photons/ light and its subjective experiences. We also discuss that amodal and modal visual completions are possible due to the visual perception induced visualization when the brain tries to interpret the unseen parts of objects or represent features of perceived objects that are not actually visible. It is raised that continuously produced intrinsic bioluminescent photons from retinal lipid peroxidation may have functional role in initial development of retinogeniculate pathways as well as initial appearance topographic organizations of V1 before birth. Finally, the metaphysical framework is the extended version of dual-aspect monism (DAMv) that has the least number of problems compared to all other frameworks and hence it is better than the materialism that is currently dominant in science.
Collapse
|
8
|
Dea M, Hamadjida A, Elgbeili G, Quessy S, Dancause N. Different Patterns of Cortical Inputs to Subregions of the Primary Motor Cortex Hand Representation in Cebus apella. Cereb Cortex 2016; 26:1747-61. [PMID: 26966266 PMCID: PMC4785954 DOI: 10.1093/cercor/bhv324] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The primary motor cortex (M1) plays an essential role in the control of hand movements in primates and is part of a complex cortical sensorimotor network involving multiple premotor and parietal areas. In a previous study in squirrel monkeys, we found that the ventral premotor cortex (PMv) projected mainly to 3 regions within the M1 forearm representation [rostro-medial (RM), rostro-lateral (RL), and caudo-lateral (CL)] with very few caudo-medial (CM) projections. These results suggest that projections from premotor areas to M1 are not uniform, but rather segregated into subregions. The goal of the present work was to study how inputs from diverse areas of the ipsilateral cortical network are organized within the M1 hand representation. In Cebus apella, different retrograde neuroanatomical tracers were injected in 4 subregions of the hand area of M1 (RM, RL, CM, and CL). We found a different pattern of input to each subregion of M1. RM receives inputs predominantly from dorsal premotor cortex, RL from PMv, CM from area 5, and CL from area 2. These results support that the M1 hand representation is composed of several subregions, each part of a unique cortical network.
Collapse
Affiliation(s)
- Melvin Dea
- Département de Neurosciences, Université de Montréal, Montréal, Québec, Canada
| | - Adjia Hamadjida
- Département de Neurosciences, Université de Montréal, Montréal, Québec, Canada Groupe de recherche sur le système nerveux central (GRSNC), Université de Montréal, Montréal, Québec, Canada
| | - Guillaume Elgbeili
- Psychosocial Research Division, Douglas Institute Research Centre, Verdun, QC, Canada
| | - Stephan Quessy
- Département de Neurosciences, Université de Montréal, Montréal, Québec, Canada
| | - Numa Dancause
- Département de Neurosciences, Université de Montréal, Montréal, Québec, Canada Groupe de recherche sur le système nerveux central (GRSNC), Université de Montréal, Montréal, Québec, Canada
| |
Collapse
|
9
|
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.
Collapse
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
| |
Collapse
|
10
|
Yu L, Yin X, Dai C, Liang M, Wei L, Li C, Zhang J, Xie B, Wang J. Morphologic changes in the anterior and posterior subregions of V1 and V2 and the V5/MT+ in patients with primary open-angle glaucoma. Brain Res 2014; 1588:135-43. [PMID: 25199592 DOI: 10.1016/j.brainres.2014.09.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 08/20/2014] [Accepted: 09/01/2014] [Indexed: 10/24/2022]
Abstract
The aim of this study was to investigate possible morphologic changes of the visual cortex in primary open-angle glaucoma (POAG) with varying severity. Twenty normal controls (NC), 19 mild (MP) and 17 severe (SP) POAG patients were recruited and scanned using magnetic resonance imaging. Multi-parameter morphologic analyses with regions of interest (V5/MT+, anterior and posterior subregions of V1 and V2) were used to assess the cortical changes among the three groups. Compared with the NC group, decreased cortical thickness was detected in the V5/MT+ area in the MP group and in all of the investigated visual areas except the posterior subregion of V1 in the SP group. Unexpectedly, cortical thinning of the posterior subregion of V2 was detected in the SP group compared with the NC and MP groups. For the other morphologic parameters, only gray matter volume in the posterior subregion of V2 and mean curvature in the V5/MT+ were significantly changed in the SP group. In addition, the clinical measurements were positively correlated with the cortical thickness of the V5/MT+ and the posterior subregion of V2. In conclusion, the V5/MT+ area is involved in early disruption of POAG and the cortical degeneration may be progressive and heterogeneous in different visual cortices. Early neuroprotective therapies on the retina and central visual system may help to preserve vision in patients with POAG.
Collapse
Affiliation(s)
- Longhua Yu
- Department of Radiology, Southwest Hospital, Third Military Medical University, Chongqing, 400038 China; Department of Radiology, 401st Hospital of the People׳s Liberation Army, Qingdao, Shandong, China
| | - Xuntao Yin
- Department of Radiology, Southwest Hospital, Third Military Medical University, Chongqing, 400038 China; McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Chao Dai
- Ophthalmology Research Center, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Minglong Liang
- Department of Radiology, Southwest Hospital, Third Military Medical University, Chongqing, 400038 China
| | - Luqing Wei
- Department of Radiology, Southwest Hospital, Third Military Medical University, Chongqing, 400038 China
| | - Chuanming Li
- Department of Radiology, Southwest Hospital, Third Military Medical University, Chongqing, 400038 China
| | - Jiuquan Zhang
- Department of Radiology, Southwest Hospital, Third Military Medical University, Chongqing, 400038 China
| | - Bing Xie
- Department of Radiology, Southwest Hospital, Third Military Medical University, Chongqing, 400038 China.
| | - Jian Wang
- Department of Radiology, Southwest Hospital, Third Military Medical University, Chongqing, 400038 China.
| |
Collapse
|
11
|
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.
Collapse
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
| |
Collapse
|
12
|
Abstract
The short-wavelength-sensitive (S) cones play an important role in color vision of primates, and may also contribute to the coding of other visual features, such as luminance and motion. The color signals carried by the S cones and other cone types are largely separated in the subcortical visual pathway. Studies on nonhuman primates or humans have suggested that these signals are combined in the striate cortex (V1) following a substantial amplification of the S-cone signals in the same area. In addition to reviewing these studies, this review describes the circuitry in V1 that may underlie the processing of the S-cone signals and the dynamics of this processing. It also relates the interaction between various cone signals in V1 to the results of some psychophysical and physiological studies on color perception, which leads to a discussion of a previous model, in which color perception is produced by a multistage processing of the cone signals. Finally, I discuss the processing of the S-cone signals in the extrastriate area V2.
Collapse
|
13
|
Distinct functional organizations for processing different motion signals in V1, V2, and V4 of macaque. J Neurosci 2012; 32:13363-79. [PMID: 23015427 DOI: 10.1523/jneurosci.1900-12.2012] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Motion perception is qualitatively invariant across different objects and forms, namely, the same motion information can be conveyed by many different physical carriers, and it requires the processing of motion signals consisting of direction, speed, and axis or trajectory of motion defined by a moving object. Compared with the representation of orientation, the cortical processing of these different motion signals within the early ventral visual pathway of the primate remains poorly understood. Using drifting full-field noise stimuli and intrinsic optical imaging, along with cytochrome-oxidase staining, we found that the orientation domains in macaque V1, V2, and V4 that processed orientation signals also served to process motion signals associated with the axis and speed of motion. In contrast, direction domains within the thick stripes of V2 demonstrated preferences that were independent of motion speed. The population responses encoding the orientation and motion axis could be precisely reproduced by a spatiotemporal energy model. Thus, our observation of orientation domains with dual functions in V1, V2, and V4 directly support the notion that the linear representation of the temporal series of retinotopic activations may serve as another motion processing strategy in primate ventral visual pathway, contributing directly to fine form and motion analysis. Our findings further reveal that different types of motion information are differentially processed in parallel and segregated compartments within primate early visual cortices, before these motion features are fully combined in high-tier visual areas.
Collapse
|
14
|
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.
Collapse
Affiliation(s)
- Mary K L Baldwin
- Department of Psychology, Vanderbilt University, Nashville Tennessee 37212, USA
| | | | | | | | | |
Collapse
|
15
|
Bókkon I, Salari V, Tuszynski JA. Emergence of intrinsic representations of images by feedforward and feedback processes and bioluminescent photons in early retinotopic areas. J Integr Neurosci 2012; 10:47-64. [PMID: 21425482 DOI: 10.1142/s0219635211002610] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2010] [Accepted: 11/16/2010] [Indexed: 11/18/2022] Open
Abstract
Recently, we put forward a redox molecular hypothesis involving the natural biophysical substrate of visual perception and imagery. Here, we explicitly propose that the feedback and feedforward iterative operation processes can be interpreted in terms of a homunculus looking at the biophysical picture in our brain during visual imagery. We further propose that the brain can use both picture-like and language-like representation processes. In our interpretation, visualization (imagery) is a special kind of representation i.e., visual imagery requires a peculiar inherent biophysical (picture-like) mechanism. We also conjecture that the evolution of higher levels of complexity made the biophysical picture representation of the external visual world possible by controlled redox and bioluminescent nonlinear (iterative) biochemical reactions in the V1 and V2 areas during visual imagery. Our proposal deals only with the primary level of visual representation (i.e. perceived "scene").
Collapse
Affiliation(s)
- I Bókkon
- Doctoral School of Pharmaceutical and Pharmacological Sciences, Semmelweis University, Hungary.
| | | | | |
Collapse
|
16
|
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.
Collapse
Affiliation(s)
| | - Evelina Tapia
- Center for Neuro-Engineering and Cognitive Science, University of
Houston, Houston, TX, USA
| |
Collapse
|
17
|
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.
Collapse
|
18
|
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.
Collapse
|
19
|
Cooper CG, Ramsden BM. Clustered cortical organization and the enhanced probability of intra-areal functional integration. NETWORK (BRISTOL, ENGLAND) 2010; 21:1-34. [PMID: 20735172 DOI: 10.3109/0954898x.2010.484475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Similarly responsive neurons organize into submillimeter-sized clusters (domains) across many neocortical areas, notably in Areas V1 and V2 of primate visual cortex. While this clustered organization may arise from wiring minimization or from self-organizing development, it could potentially support important neural computation benefits. Here, we suggest that domain organization offers an efficient computational mechanism for intra-areal functional integration in certain cortical areas and hypothesize that domain proximity could support a higher-than-expected spatial correlation of their respective terminals yielding higher probabilities of integration of differing domain preferences. To investigate this hypothesis we devised a spatial model inspired by known parameters of V2 functional organization, where neighboring domains prefer either colored or oriented stimuli. Preference-selective joint probabilities were calculated for model terminal co-occurrence with configurations encompassing diverse domain proximity, shape, and projection. Compared to random distributions, paired neighboring domains (< or =1200 microm apart) yielded significantly enhanced coincidence of terminals converging from each domain. Using this reference data, a second larger-scale model indicated that V2 domain organization may accommodate relatively complete sets of intra-areal color/orientation integrations. Together, these data indicate that domain organization could support significant and efficient intra-areal integration of different preferences and suggest further experiments investigating prevalence and mechanisms of domain-mediated intra-areal integration.
Collapse
Affiliation(s)
- C Garret Cooper
- Department of Neurobiology and Anatomy, and Sensory Neuroscience Research Center, West Virginia University School of Medicine, USA
| | | |
Collapse
|
20
|
Shushruth S, Ichida JM, Levitt JB, Angelucci A. Comparison of spatial summation properties of neurons in macaque V1 and V2. J Neurophysiol 2009; 102:2069-83. [PMID: 19657084 PMCID: PMC2775374 DOI: 10.1152/jn.00512.2009] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
In visual cortex, responses to stimulation of the receptive field (RF) are modulated by simultaneous stimulation of the RF surround. The mechanisms for surround modulation remain unidentified. We previously proposed that in the primary visual cortex (V1), near surround modulation is mediated by geniculocortical and horizontal connections and far surround modulation by interareal feedback connections. To understand spatial integration in the secondary visual cortex (V2) and its underlying circuitry, we have characterized spatial summation in different V2 layers and stripe compartments and compared it to that in V1. We used grating stimuli in circular and annular apertures of different sizes to estimate the extent and sensitivity of RF and surround components in V1 and V2. V2 RFs and surrounds were twice as large as those in V1. As in V1, V2 RFs doubled in size when measured at low contrast. In both V1 and V2, surrounds were about fivefold the size of the RF and the far surround could exceed 12.5° in radius, averaging 5.5° in V1 and 9.2° in V2. The strength of surround suppression was similar in both areas. Thus although differing in spatial scale, the interactions among RF components are similar in V1 and V2, suggesting similar underlying mechanisms. As in V1, the extent of V2 horizontal connections matches that of the RF center, but is much smaller than the largest far surrounds, which likely derive from interareal feedback. In V2, we found no laminar or stripe differences in size and magnitude of surround suppression, suggesting conservation across stripes of the basic circuit for surround modulation.
Collapse
Affiliation(s)
- S Shushruth
- Department of Ophthalmology and Visual Science, Moran Eye Center, University of Utah, Salt Lake City, Utah, USA
| | | | | | | |
Collapse
|
21
|
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.
Collapse
Affiliation(s)
- Heejin Lim
- Department of Neurobiology and Anatomy, University of Texas Medical School-Houston, Houston, TX 77030, USA
| | | | | | | | | |
Collapse
|
22
|
Bókkon I. Visual perception and imagery: A new molecular hypothesis. Biosystems 2009; 96:178-84. [DOI: 10.1016/j.biosystems.2009.01.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Revised: 01/25/2009] [Accepted: 01/25/2009] [Indexed: 12/01/2022]
|
23
|
Nassi JJ, Callaway EM. Parallel processing strategies of the primate visual system. Nat Rev Neurosci 2009; 10:360-72. [PMID: 19352403 DOI: 10.1038/nrn2619] [Citation(s) in RCA: 461] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Incoming sensory information is sent to the brain along modality-specific channels corresponding to the five senses. Each of these channels further parses the incoming signals into parallel streams to provide a compact, efficient input to the brain. Ultimately, these parallel input signals must be elaborated on and integrated in the cortex to provide a unified and coherent percept. Recent studies in the primate visual cortex have greatly contributed to our understanding of how this goal is accomplished. Multiple strategies including retinal tiling, hierarchical and parallel processing and modularity, defined spatially and by cell type-specific connectivity, are used by the visual system to recover the intricate detail of our visual surroundings.
Collapse
Affiliation(s)
- Jonathan J Nassi
- Harvard Medical School, Department of Neurobiology, 220 Longwood Avenue, Boston, Massachusetts 02115, USA
| | | |
Collapse
|
24
|
Kaskan PM, Lu HD, Dillenburger BC, Kaas JH, Roe AW. The organization of orientation-selective, luminance-change and binocular- preference domains in the second (V2) and third (V3) visual areas of New World owl monkeys as revealed by intrinsic signal optical imaging. ACTA ACUST UNITED AC 2008; 19:1394-407. [PMID: 18842661 DOI: 10.1093/cercor/bhn178] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Optical imaging was used to map patterns of visually evoked activation in the second (V2) and third (V3) visual areas of owl monkeys. Modular patterns of activation were produced in response to stimulation with oriented gratings, binocular versus monocular stimulation, and stimuli containing wide-field luminance changes. In V2, luminance-change domains tended to lie between domains selective for orientation. Regions preferentially activated by binocular stimulation co-registered with orientation-selective domains. Co-alignment of images with cytochrome oxidase (CO)-processed sections revealed functional correlates of 2 types of CO-dense regions in V2. Orientation-responsive domains and binocular domains were correlated with the locations of CO-thick stripes, and luminance-change domains were correlated with the locations of CO-thin stripes. In V3, orientation preference, luminance-change, and binocular preference domains were observed, but were more irregularly arranged than those in V2. Our data suggest that in owl monkey V2, consistent with that in macaque monkeys, modules for processing contours and binocularity exist in one type of compartment and that modules related to processing-surface features exist within a separate type of compartment.
Collapse
Affiliation(s)
- Peter M Kaskan
- Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA.
| | | | | | | | | |
Collapse
|
25
|
Soares JGM, Rosado De Castro PH, Fiorani M, Nascimento-Silva S, Gattass R. Distribution of neurofilament proteins in the lateral geniculate nucleus, primary visual cortex, and area MT of adult Cebus monkeys. J Comp Neurol 2008; 508:605-14. [PMID: 18383052 DOI: 10.1002/cne.21718] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We investigated the distribution pattern of SMI-32-immunopositive cells in the lateral geniculate nucleus (LGN) and in the primary (V1) and middle temporal (MT) cortical visual areas of the adult New World monkey Cebus apella. In the LGN, the reaction for SMI-32 labeled cells in both the magnocellular (M) and parvocellular (P) layers. However, the cellular label was heavier in M layers, which also showed a more intense labeling in the neuropil. In V1, the reaction showed a lamination pattern, with the heaviest labeling occurring in layer 4B and upper layer 6 (layers that project to area MT). Area MT shows a dense band of labeled neuropil and large pyramidal neurons in layer 3, large darkly labeled but less densely packed neurons in layer 5, and a population of small, lightly labeled cells in layer 6. These results resemble those found in other New and Old World monkeys, which suggest that the preferential labeling of projection neurons associated with fast-conducting pathways to the extrastriate dorsal stream is a common characteristic of simian primates. In the superficial layers of V1 in Cebus monkeys, however, SMI-32-labeled neurons are found in both cytochrome oxidase blobs and interblob regions. In this aspect, our results in Cebus are similar to those found in the Old World monkey Macaca and different from those described for squirrel monkey, a smaller New World Monkey. In Cebus, as well as in Macaca, there is no correlation between SMI-32 distribution and the blob pattern.
Collapse
|
26
|
Dancause N, Barbay S, Frost SB, Mahnken JD, Nudo RJ. Interhemispheric connections of the ventral premotor cortex in a new world primate. J Comp Neurol 2008; 505:701-15. [PMID: 17948893 DOI: 10.1002/cne.21531] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This study describes the pattern of interhemispheric connections of the ventral premotor cortex (PMv) distal forelimb representation (DFL) in squirrel monkeys. Our objectives were to describe qualitatively and quantitatively the connections of PMv with contralateral cortical areas. Intracortical microstimulation techniques (ICMS) guided the injection of the neuronal tract tracers biotinylated dextran amine or Fast blue into PMv DFL. We classified the interhemispheric connections of PMv into three groups. Major connections were found in the contralateral PMv and supplementary motor area (SMA). Intermediate interhemispheric connections were found in the rostral portion of the primary motor cortex, the frontal area immediately rostral and ventral to PMv (FR), cingulate motor areas (CMAs), and dorsal premotor cortex (PMd). Minor connections were found inconsistently across cases in the anterior operculum (AO), posterior operculum/inferior parietal cortex (PO/IP), and posterior parietal cortex (PP), areas that consistently show connections with PMv in the ipsilateral hemisphere. Within-case comparisons revealed that the percentage of PMv connections with contralateral SMA and PMd are higher than the percentage of PMv connections with these areas in the ipsilateral hemisphere; percentages of PMv connections with contralateral M1 rostral, FR, AO, and the primary somatosensory cortex are lower than percentages of PMv connections with these areas in the ipsilateral hemisphere. These studies increase our knowledge of the pattern of interhemispheric connection of PMv. They help to provide an anatomical foundation for understanding PMv's role in motor control of the hand and interhemispheric interactions that may underlie the coordination of bimanual movements.
Collapse
Affiliation(s)
- Numa Dancause
- Department of Neurology, University of Rochester Medical Center, Rochester, New York 14642, USA.
| | | | | | | | | |
Collapse
|
27
|
Nassi JJ, Callaway EM. Specialized circuits from primary visual cortex to V2 and area MT. Neuron 2007; 55:799-808. [PMID: 17785186 PMCID: PMC2727861 DOI: 10.1016/j.neuron.2007.07.037] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2007] [Revised: 07/06/2007] [Accepted: 07/19/2007] [Indexed: 11/27/2022]
Abstract
Primary visual cortex recombines inputs from magnocellular (M) and parvocellular (P) streams to create functionally specialized outputs. Understanding these input-output relationships is complicated by the fact that layer 4B, which provides outputs to dorsal visual areas, contains multiple cell types. Using a modified rabies virus that expresses green fluorescent protein, we show that layer 4B neurons projecting to MT are a majority spiny stellate, whereas those projecting to V2 are overwhelmingly pyramidal. Regardless of cell type, MT-projecting neurons have larger cell bodies, more dendritic length, and are deeper within layer 4B. Furthermore, MT-projecting pyramidal neurons are located preferentially underneath cytochrome oxidase blobs, indicating that MT-projecting neurons of both types restrict their dendrites to M-recipient zones. We conclude that MT-projecting layer 4B neurons are specialized for the fast transmission of information from the M pathway, while V2-projecting neurons are likely to mediate slower computations involving mixed M and P signals.
Collapse
Affiliation(s)
- Jonathan J Nassi
- Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | | |
Collapse
|
28
|
Nassi JJ, Callaway EM. Multiple circuits relaying primate parallel visual pathways to the middle temporal area. J Neurosci 2006; 26:12789-98. [PMID: 17151282 PMCID: PMC2629496 DOI: 10.1523/jneurosci.4044-06.2006] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Parallel pathways in the primate visual system parse the sensory signal into magnocellular (M), parvocellular (P), and koniocellular (K) streams. These pathways remain anatomically separate and distinct from their origination in different retinal ganglion cell types, through distinct layers of the lateral geniculate nucleus, and into primary visual cortex (V1), with the M pathway terminating primarily in layer 4Calpha, the P pathway in layer 4Cbeta, and the K pathway in the cytochrome oxidase blobs of layer 2/3. Recent studies indicate that outputs from V1 are less compartmental than previously thought, making it difficult to assess the contributions of M and P pathways to areas beyond V1 in the dorsal and ventral streams. Here we use rabies virus as a retrograde transsynaptic tracer to study the contributions of M and P pathways to areas middle temporal (MT), V3, and V2 of macaque monkey. We find that, although disynaptic inputs through layer 4C of V1 to dorsal stream area MT are dominated by the M pathway, within an additional three synapses MT receives a substantial P input. This P input is unlikely to reach MT via V3, which we show also receives disynaptic inputs dominated by the M pathway. We find that disynaptic inputs to V2, however, can be more balanced and may carry convergent M and P input to MT. Our observations provide evidence for multiple pathways from V1 to MT, with varying degrees of M and P convergence. Each pathway likely provides functionally specialized information to MT and dorsal stream visual processing.
Collapse
Affiliation(s)
- Jonathan J. Nassi
- Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, La Jolla, California 92037
| | - Edward M. Callaway
- Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, La Jolla, California 92037
| |
Collapse
|
29
|
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.
Collapse
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.
| | | | | | | |
Collapse
|
30
|
Dancause N, Barbay S, Frost SB, Plautz EJ, Stowe AM, Friel KM, Nudo RJ. Ipsilateral connections of the ventral premotor cortex in a new world primate. J Comp Neurol 2006; 495:374-90. [PMID: 16485282 PMCID: PMC2583355 DOI: 10.1002/cne.20875] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The present study describes the pattern of connections of the ventral premotor cortex (PMv) with various cortical regions of the ipsilateral hemisphere in adult squirrel monkeys. Particularly, we 1) quantified the proportion of inputs and outputs that the PMv distal forelimb representation shares with other areas in the ipsilateral cortex and 2) defined the pattern of PMv connections with respect to the location of the distal forelimb representation in primary motor cortex (M1), primary somatosensory cortex (S1), and supplementary motor area (SMA). Intracortical microstimulation techniques (ICMS) were used in four experimentally naïve monkeys to identify M1, PMv, and SMA forelimb movement representations. Multiunit recording techniques and myelin staining were used to identify the S1 hand representation. Then, biotinylated dextran amine (BDA; 10,000 MW) was injected in the center of the PMv distal forelimb representation. After tangential sectioning, the distribution of BDA-labeled cell bodies and terminal boutons was documented. In M1, labeling followed a rostrolateral pattern, largely leaving the caudomedial M1 unlabeled. Quantification of somata and terminals showed that two areas share major connections with PMv: M1 and frontal areas immediately rostral to PMv, designated as frontal rostral area (FR). Connections with this latter region have not been described previously. Moderate connections were found with PMd, SMA, anterior operculum, and posterior operculum/inferior parietal area. Minor connections were found with diverse areas of the precentral and parietal cortex, including S1. No statistical difference between the proportions of inputs and outputs for any location was observed, supporting the reciprocity of PMv intracortical connections.
Collapse
Affiliation(s)
- Numa Dancause
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas 66160, USA.
| | | | | | | | | | | | | |
Collapse
|
31
|
Abstract
Parallel streams from the primary visual cortex (V1) to the second visual area (V2) are thought to mediate different aspects of visual perception in primates. One hypothesis is that the projection from cytochrome oxidase patches to thin stripes is responsible for color, whereas a separate pathway from interpatches to pale stripes mediates form. Recently, the notion of segregated pathways has been challenged by a report showing that patches and interpatches project equally to thin stripes. We made injections of a retrograde tracer, cholera toxin-B (CTB-Au), into macaque V2 thin stripes and counted the number of labeled cells in patches versus interpatches in layer 2/3. Analysis of eight thin-stripe injections showed that a mean of 81% of labeled cells were located in patches (defined as 33% of the surface area of V1). This result confirms that the projection to thin stripes arises predominately from patches. To assess the segregation of patch and interpatch projections, we injected CTB-Au in a pale stripe and horseradish peroxidase in an adjacent thin stripe. In both successful cases, interdigitated fields of labeled cells were present in V1. Less than 1% of cells were double-labeled, indicating that the populations of cells supplying thin stripes and pale stripes are quite independent. This finding means that different signals are likely conveyed by patches and interpatches to V2.
Collapse
Affiliation(s)
- Lawrence C Sincich
- Beckman Vision Center, University of California, San Francisco, California 94143, USA
| | | |
Collapse
|
32
|
Dancause N, Barbay S, Frost SB, Plautz EJ, Chen D, Zoubina EV, Stowe AM, Nudo RJ. Extensive cortical rewiring after brain injury. J Neurosci 2006; 25:10167-79. [PMID: 16267224 PMCID: PMC6725801 DOI: 10.1523/jneurosci.3256-05.2005] [Citation(s) in RCA: 482] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Previously, we showed that the ventral premotor cortex (PMv) underwent neurophysiological remodeling after injury to the primary motor cortex (M1). In the present study, we examined cortical connections of PMv after such lesions. The neuroanatomical tract tracer biotinylated dextran amine was injected into the PMv hand area at least 5 months after ischemic injury to the M1 hand area. Comparison of labeling patterns between experimental and control animals demonstrated extensive proliferation of novel PMv terminal fields and the appearance of retrogradely labeled cell bodies within area 1/2 of the primary somatosensory cortex after M1 injury. Furthermore, evidence was found for alterations in the trajectory of PMv intracortical axons near the site of the lesion. The results suggest that M1 injury results in axonal sprouting near the ischemic injury and the establishment of novel connections within a distant target. These results support the hypothesis that, after a cortical injury, such as occurs after stroke, cortical areas distant from the injury undergo major neuroanatomical reorganization. Our results reveal an extraordinary anatomical rewiring capacity in the adult CNS after injury that may potentially play a role in recovery.
Collapse
Affiliation(s)
- Numa Dancause
- Department of Molecular and Integrative Physiology, The University of Kansas Medical Center, Kansas City, Kansas 66160, USA.
| | | | | | | | | | | | | | | |
Collapse
|
33
|
Heider B, Jandó G, Siegel RM. Functional architecture of retinotopy in visual association cortex of behaving monkey. Cereb Cortex 2005; 15:460-78. [PMID: 15749989 PMCID: PMC1945172 DOI: 10.1093/cercor/bhh148] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
While the receptive field properties of single neurons in the inferior parietal cortex have been quantitatively described from numerous electrical measurements, the visual topography of area 7a and the adjacent dorsal prelunate area (DP) remains unknown. This lacuna may be a technical byproduct of the difficulty of reconstructing tens to hundreds of penetrations, or may be the result of varying functional retinotopic architectures. Intrinsic optical imaging, performed in behaving monkey for extended periods of time, was used to evaluate retinotopy simultaneously at multiple positions across the cortical surface. As electrical recordings through an implanted artificial dura are difficult, the measurement and quantification of retinotopy with long-term recordings was validated by imaging early visual cortex (areas V1 and V2). Retinotopic topography was found in each of the three other areas studied within a single day's experiment. However, the ventral portion of DP (DPv) had a retinotopic topography that varied from day to day, while the more dorsal aspects (DPd) exhibited consistent retinotopy. This suggests that the dorsal prelunate gyrus may consist of more than one visual area. The retinotopy of area 7a also varied from day to day. Possible mechanisms for this variability across days are discussed as well as its impact upon our understanding of the representation of extrapersonal space in the inferior parietal cortex.
Collapse
Affiliation(s)
- Barbara Heider
- Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, NJ 07102, USA
| | | | | |
Collapse
|