scholarly journals Spatial structure of neuronal receptive field in awake monkey secondary visual cortex (V2)

2016 ◽  
Vol 113 (7) ◽  
pp. 1913-1918 ◽  
Author(s):  
Lu Liu ◽  
Liang She ◽  
Ming Chen ◽  
Tianyi Liu ◽  
Haidong D. Lu ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Receptive Field ◽  
Optical Imaging ◽  
Visual Processing ◽  
Single Unit ◽  
Functional Organization ◽  
Projection Pursuit ◽  
Unit Recording ◽  
Visual Neurons ◽  
Aspect Ratios

Visual processing depends critically on the receptive field (RF) properties of visual neurons. However, comprehensive characterization of RFs beyond the primary visual cortex (V1) remains a challenge. Here we report fine RF structures in secondary visual cortex (V2) of awake macaque monkeys, identified through a projection pursuit regression analysis of neuronal responses to natural images. We found that V2 RFs could be broadly classified as V1-like (typical Gabor-shaped subunits), ultralong (subunits with high aspect ratios), or complex-shaped (subunits with multiple oriented components). Furthermore, single-unit recordings from functional domains identified by intrinsic optical imaging showed that neurons with ultralong RFs were primarily localized within pale stripes, whereas neurons with complex-shaped RFs were more concentrated in thin stripes. Thus, by combining single-unit recording with optical imaging and a computational approach, we identified RF subunits underlying spatial feature selectivity of V2 neurons and demonstrated the functional organization of these RF properties.

scholarly journals The functional organization of high-level visual cortex determines the representation of complex visual stimuli

2019 ◽  
Author(s):  
Libi Kliger ◽  
Galit Yovel
Keyword(s):  
Visual Cortex ◽  
Single Unit ◽  
General Framework ◽  
Single Neuron ◽  
Functional Organization ◽  
Task Demands ◽  
Unit Recording ◽  
Complex Stimuli ◽  
Visual Scenes ◽  
High Level

SummaryA hallmark of high-level visual cortex is its functional organization of neighboring clusters of neurons that are selective to single categories such as faces, bodies and objects. However, visual scenes are typically composed of multiple categories. How does category-selective cortex represent such complex stimuli? According to a normalization mechanism, the response of a single neuron to multiple stimuli is normalized by the response of its neighboring neurons (normalization pool). Here we show that category-selectivity, measured with fMRI, can provide an estimate for the heterogeneity of the normalization pool, which determines the response to multiple stimuli. These results provide a general framework for the varying representations of multiple stimuli that were reported in different regions of category-selective cortex in neuroimaging and single-unit recording studies. This type of organization may enable a dynamic and flexible representation of complex visual scenes that can be modulated by higher-level cognitive systems according to task demands.

Anatomical and functional organization of pathway from superior colliculus to lateral posterior nucleus in hamster

1984 ◽  
Vol 51 (3) ◽  
pp. 407-431 ◽  
Author(s):  
R. D. Mooney ◽  
S. E. Fish ◽  
R. W. Rhoades
Keyword(s):  
Receptive Field ◽  
Superior Colliculus ◽  
Functional Organization ◽  
Single Cells ◽  
Angular Separation ◽  
Unit Recording ◽  
Receptive Field Properties ◽  
Lateral Posterior ◽  
Lateral Posterior Nucleus ◽  
Lp Cells

A series of anatomical (autoradiographic and horseradish peroxidase, HRP) and electrophysiological experiments were carried out to determine the organization of the pathway from the superior colliculus (SC) to the lateral posterior nucleus (LP) in the hamster. Small, electrophoretic HRP deposits restricted to LP labeled numerous cells in both the ipsilateral and contralateral colliculus. Over 95% of the labeled cells were located in the lower one-half of the stratum griseum superficiale (SGS) and the upper stratum opticum (SO). A number of different morphological cell types contributed axons to the tecto-LP pathway. The receptive-field properties of antidromically activated tecto-LP neurons were delineated using extracellular single-unit recording techniques. Ninety-eight percent of the tecto-LP cells recorded were isolated in the SGS and SO. All tecto-LP cells responded more vigorously to moving than to flashed stimuli, one-third were directionally selective, and one-third exhibited some degree of speed selectivity. The responses of tecto-LP neurons did not differ appreciably from those of superficial layer collicular cells that could not be antidromically activated by LP shocks. Small pressure injections or electrophoretic deposits of [3H]leucine into sites with known retinotopy in the superficial collicular laminae were used to determine whether or not the tecto-LP projection in hamster was topographically organized. Injections anywhere in the SGS and SO yielded dense label in almost all of the caudal (LPc) and rostrolateral (LPrl) subnuclei of LP, ipsilaterally, and sparser labeling in these same subnuclei, contralaterally. No injection produced significant labeling in the rostromedial (LPrm) subnucleus. Our autoradiographic data gave no indication of any topographic order in the tecto-LP projection. Electrophysiological methods were also used to map the tecto-LP projection. Multiple stimulating microelectrodes were positioned at physiologically defined sites in the SGS, and single cells were recorded in LP, ipsilaterally. Threshold currents for activation of LP cells from different collicular sites were then compared with the angular separation of SC and LP receptive-field centers. No significant correlation between these two variables was noted, again indicating a lack of topographic organization in the tecto-LP projection. The receptive-field properties of individual LP neurons (n = 211) were also assessed and correlated with subnuclear location and responsivity to SC shocks.(ABSTRACT TRUNCATED AT 400 WORDS)

Form Processing Modules in Primate Area V4

1997 ◽  
Vol 77 (4) ◽  
pp. 2191-2196 ◽  
Author(s):  
Geoffrey M. Ghose ◽  
Daniel Y. Ts'O
Keyword(s):  
Optical Imaging ◽  
Functional Organization ◽  
Visual Fields ◽  
Central Position ◽  
Unit Recording ◽  
Form Analysis ◽  
Area V4 ◽  
Form Processing ◽  
Object Based

Ghose, Geoffrey M. and Daniel Y. Ts'o. Form processing modules in primate area V4. J. Neurophysiol. 77: 2191–2196, 1997. Area V4 occupies a central position among the areas of the primate cerebral cortex involved with object recognition and analysis. Consistent with this role, neurons in V4 are selective for many visual attributes including color, orientation, and binocular disparity. However, it is uncertain whether cells within V4 are organized with respect to these properties. In this study we used in vivo optical imaging and electrophysiology in macaque visual cortex to show that cells that share certain physiological properties are indeed grouped together in V4. Our results revealed regions containing cells with common orientation selectivity. These regions were similar in size to those seen in V2 and much larger than those seen in V1 and were confirmed by appropriately targeted single-unit recording. Surprisingly, orientation organization visible through imaging was limited to the portion of V4 representing the central visual fields. Optical imaging also revealed a functional organization related to stimulus size. Size-sensitive regions (S regions) contained cells that were strongly suppressed by large stimuli. In contrast to V2, S regions in V4 contain orientation domains. These results suggest that V4 contains modular assemblies of cells related to particular aspects of form analysis. Such organization may contribute to the construction of object-based representations.

Temporal Properties of Inputs to Direction-Selective Neurons in Monkey V1

2005 ◽  
Vol 94 (1) ◽  
pp. 282-294 ◽  
Author(s):  
Alan B Saul ◽  
Peter L Carras ◽  
Allen L Humphrey
Keyword(s):  
Visual Cortex ◽  
Single Unit ◽  
Direction Selectivity ◽  
Single Unit Recording ◽  
High Contrast ◽  
Cortical Cells ◽  
Unit Recording ◽  
Space And Time ◽  
Temporal Properties ◽  
Sustained Responses

Motion in the visual scene is processed by direction-selective neurons in primary visual cortex. These cells receive inputs that differ in space and time. What are these inputs? A previous single-unit recording study in anesthetized monkey V1 proposed that the two major streams arising in the primate retina, the M and P pathways, differed in space and time as required to create direction selectivity. We confirmed that cortical cells driven by P inputs tend to have sustained responses. The M pathway, however, as assessed by recordings in layer 4Cα and from cells with high contrast sensitivity, is not purely transient. The diversity of timing in the M stream suggests that combinations of M inputs, as well as of M and P inputs, create direction selectivity.

scholarly journals The Embedded Neuron, the Enactive Field?

2009 ◽  
Author(s):  
Mazviita Chirimuuta ◽  
Ian Gold
Keyword(s):  
Visual Cortex ◽  
Receptive Field ◽  
Primary Visual Cortex ◽  
Computational Vision ◽  
Visual Neurons ◽  
Visual Theory ◽  
Classical Conception ◽  
Contrast Discrimination ◽  
Classical Picture

This article examines the concept of the receptive field (RF) of visual neurons. It introduces the concept of visual RFs by discussing the classical picture of primary visual cortex (V1) physiology and discusses the psychophysics and computational vision of contrast discrimination to place the visual neurophysiology in context. It evaluates some recent data which questioned the classical conception of the RF and considers some options available for absorbing these data into visual theory.

scholarly journals Mesoscale correlation structure with single cell resolution during visual coding

2018 ◽  
Author(s):  
Yiyi Yu ◽  
Jeffrey N. Stirman ◽  
Christopher R. Dorsett ◽  
Spencer L. Smith
Keyword(s):  
Visual Cortex ◽  
Receptive Field ◽  
Visual Information ◽  
Functional Organization ◽  
Brain Regions ◽  
Correlation Structure ◽  
Visual Coding ◽  
Cortical Areas ◽  
The Individual ◽  
Higher Visual Areas

AbstractNeural circuitry represents sensory input with patterns of spiking activity. Across brain regions, initial representations are transformed to ultimately drive adaptive behavior. In mammalian neocortex, visual information is processed by primary visual cortex (V1) and multiple higher visual areas (HVAs). The interconnections of these brain regions, over which transformations can occur, span millimeters or more. Shared variability in spiking responses between neurons, called “noise correlations” (NCs), can be due to shared input and/or direct or indirect connectivity. Thus, NCs provide insight into the functional connectivity of neuronal circuits. In this study, we used subcellular resolution, mesoscale field-of-view two-photon calcium imaging to systematically characterize the NCs for pairs of layer 2/3 neurons across V1 and four HVAs (areas LM, LI, AL and PM) of mice. The average NCs for pairs of neurons within or across cortical areas were orders of magnitude larger than trial-shuffled control values. We characterized the modulation of NCs by neuron distance, tuning similarity, receptive field overlap, and stimulus type over millimeter scale distances in mouse visual cortex, within and across V1 and multiple HVAs. NCs were positively correlated with shared tuning and receptive field overlap, even across cortical areas and millimeter length scales. We compared the structure of these NCs to that of hypothetical networks to determine what network types can account for the results. We found that to reproduce the NC networks, neuron connectivity was regulated by both feature similarities and hub mechanism. Overall, these results revealed principles for the functional organization and correlation structure at the individual neuron level across multiple cortical areas, which can inform and constrain computational theories of cortical networks.

scholarly journals Low rank mechanisms underlying flexible visual representations

2020 ◽  
Vol 117 (47) ◽  
pp. 29321-29329 ◽  
Author(s):  
Douglas A. Ruff ◽  
Cheng Xue ◽  
Lily E. Kramer ◽  
Faisal Baqai ◽  
Marlene R. Cohen
Keyword(s):  
Visual Cortex ◽  
Cognitive Processes ◽  
Task Switching ◽  
Visual Processing ◽  
Neuronal Population ◽  
Low Rank ◽  
Visual Neurons ◽  
Sensory Stimuli ◽  
Neuronal Populations ◽  
Wide Range

Neuronal population responses to sensory stimuli are remarkably flexible. The responses of neurons in visual cortex have heterogeneous dependence on stimulus properties (e.g., contrast), processes that affect all stages of visual processing (e.g., adaptation), and cognitive processes (e.g., attention or task switching). Understanding whether these processes affect similar neuronal populations and whether they have similar effects on entire populations can provide insight into whether they utilize analogous mechanisms. In particular, it has recently been demonstrated that attention has low rank effects on the covariability of populations of visual neurons, which impacts perception and strongly constrains mechanistic models. We hypothesized that measuring changes in population covariability associated with other sensory and cognitive processes could clarify whether they utilize similar mechanisms or computations. Our experimental design included measurements in multiple visual areas using four distinct sensory and cognitive processes. We found that contrast, adaptation, attention, and task switching affect the variability of responses of populations of neurons in primate visual cortex in a similarly low rank way. These results suggest that a given circuit may use similar mechanisms to perform many forms of modulation and likely reflects a general principle that applies to a wide range of brain areas and sensory, cognitive, and motor processes.

scholarly journals Population receptive field shapes in early visual cortex are nearly circular

2020 ◽  
Author(s):  
Garikoitz Lerma-Usabiaga ◽  
Jonathan Winawer ◽  
Brian A. Wandell
Keyword(s):  
Visual Cortex ◽  
Visual Field ◽  
Receptive Field ◽  
Receptive Fields ◽  
Ground Truth ◽  
Central Position ◽  
Data Set ◽  
Ground Truth Data ◽  
Aspect Ratios ◽  
Early Visual Cortex

AbstractThe visual field region where a stimulus evokes a neural response is called the receptive field (RF). Analytical tools combined with functional MRI can estimate the receptive field of the population of neurons within a voxel. Circular population RF (pRF) methods accurately specify the central position of the pRF and provide some information about the spatial extent (diameter) of the receptive field. A number of investigators developed methods to further estimate the shape of the pRF, for example whether the shape is more circular or elliptical. There is a report that there are many pRFs with highly elliptical pRFs in early visual cortex (V1-V3; Silson et al., 2018). Large aspect ratios (>2) are difficult to reconcile with the spatial scale of orientation columns or visual field map properties in early visual cortex. We started to replicate the experiments and found that the software used in the publication does not accurately estimate RF shape: it produces elliptical fits to circular ground-truth data. We analyzed an independent data set with a different software package that was validated over a specific range of measurement conditions, to show that in early visual cortex the aspect ratios are less than 2. Furthermore, current empirical and theoretical methods do not have enough precision to discriminate ellipses with aspect ratios of 1.5 from circles. Through simulation we identify methods for improving sensitivity that may estimate ellipses with smaller aspect ratios. The results we present are quantitatively consistent with prior assessments using other methodologies.Significance StatementWe evaluated whether the shape of many population receptive fields in early visual cortex is elliptical and differs substantially from circular. We evaluated two tools for estimating elliptical models of the pRF; one tool was valid over the measured compliance range. Using the validated tool, we found no evidence that confidently rejects circular fits to the pRF in visual field maps V1, V2 and V3. The new measurements and analyses are consistent with prior theoretical and experimental assessments in the literature.

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