Spectral Receptive Field Properties Explain Shape Selectivity in Area V4

2006 ◽  
Vol 96 (6) ◽  
pp. 3492-3505 ◽  
Author(s):  
Stephen V. David ◽  
Benjamin Y. Hayden ◽  
Jack L. Gallant
Keyword(s):  
Receptive Field ◽  
Spatial Frequency ◽  
Functional Model ◽  
Shape Selectivity ◽  
Second Order ◽  
Natural Images ◽  
Orientation Tuning ◽  
Large Set ◽  
Area V4 ◽  
V4 Neurons

Neurons in cortical area V4 respond selectively to complex visual patterns such as curved contours and non-Cartesian gratings. Most previous experiments in V4 have measured responses to small, idiosyncratic stimulus sets and no single functional model yet accounts for all of the disparate results. We propose that one model, the spectral receptive field (SRF), can explain many observations of selectivity in V4. The SRF describes tuning in terms of the orientation and spatial frequency spectrum and can, in principle, predict the response to any visual stimulus. We estimated SRFs for neurons in V4 of awake primates by linearized reverse correlation of responses to a large set of natural images. We find that V4 neurons have large orientation and spatial frequency bandwidth and often bimodal orientation tuning. For comparison, we estimated SRFs for neurons in primary visual cortex (V1). Consistent with previous observations, we find that V1 neurons have narrower bandwidth than that of V4. To determine whether estimated SRFs can account for previous observations of selectivity, we used them to predict responses to Cartesian gratings, non-Cartesian gratings, natural images, and curved contours. Based on these predictions, we find that the majority of neurons in V1 are selective for Cartesian gratings, whereas the majority of V4 neurons are selective for non-Cartesian gratings or natural images. The SRF describes visual tuning properties with a second-order nonlinear model. These results support the hypothesis that a second-order model is sufficient to describe the general mechanisms mediating shape selectivity in area V4.

Focal attention produces spatially selective processing in visual cortical areas V1, V2, and V4 in the presence of competing stimuli

1993 ◽  
Vol 70 (3) ◽  
pp. 909-919 ◽  
Author(s):  
B. C. Motter
Keyword(s):  
Receptive Field ◽  
Stimulus Presentation ◽  
Spatial Location ◽  
Differential Sensitivity ◽  
Orientation Tuning ◽  
Area V4 ◽  
Focal Attention ◽  
V4 Neurons ◽  
Visual Cortical ◽  
Competing Stimuli

1. The activity of single neurons was recorded in Macaca mulatta monkeys while they performed tasks requiring them to select a cued stimulus from an array of three to eight stimuli and report the orientation of that stimulus. Stimuli were presented in a circular array centered on the fixation target and scaled to place a single stimulus element within the receptive field of the neuron under study. The timing of the cuing event permitted the directing of visual attention to the spatial location of the correct stimulus before its presentation. 2. The effects of focal attention were examined in cortical visual areas V1, V2, and V4, where a total of 672 neurons were isolated with complete studies obtained for 94 V1, 74 V2, and 74 V4 neurons with receptive-field center eccentricities in the range 1.8-8 degrees. Under certain conditions, directed focal attention results in changes in the response of V1, V2, and V4 neurons to otherwise identical stimuli at spatially specific locations. 3. More than one-third of the neurons in each area displayed differential sensitivity when attention was directed toward versus away from the spatial location of the receptive field just before and during stimulus presentation. Both relative increases and decreases in neural activity were observed in association with attention directed at receptive-field stimuli. 4. The presence of multiple competing stimuli in the visual field was a major factor determining the presence or absence of differential sensitivity. About two-thirds of the neurons that were differentially sensitive to the attending condition in the presence of competing stimuli were not differentially sensitive when single stimuli were presented in control studies. For V1 and V2 neurons the presence of only a few (3-4) competing stimuli was sufficient for a majority of the neurons studied; a majority of the V4 neurons required six to eight stimuli in the array before significant differences between attending conditions occurred. 5. For V1 and V2 neurons the neuronal sensitivity differences between attending conditions were observed primarily at or near the peak of the orientation tuning sensitivity for each neuron; the differences were evident over a broader range of orientations in V4 neurons. 6. In conclusion, neural correlates of focal attentive processes can be observed in visual cortical processing in areas V1 and V2 as well as area V4 under conditions that require stimulus feature analysis and selective spatial processing within a field of competing stimuli.(ABSTRACT TRUNCATED AT 400 WORDS)

Quantitative Characterization of Disparity Tuning in Ventral Pathway Area V4

2005 ◽  
Vol 94 (4) ◽  
pp. 2726-2737 ◽  
Author(s):  
David A. Hinkle ◽  
Charles E. Connor
Keyword(s):  
Binocular Disparity ◽  
Orientation Tuning ◽  
Quantitative Characterization ◽  
Object Processing ◽  
Gaussian Functions ◽  
Area V4 ◽  
Ventral Pathway ◽  
Object Parts ◽  
V4 Neurons

We performed a quantitative characterization of binocular disparity-tuning functions in the ventral (object-processing) pathway of the macaque visual cortex. We measured responses of 452 area V4 neurons to stimuli with disparities ranging from −1.0 to +1.0°. Asymmetric Gaussian functions fit the raw data best (median R = 0.90), capturing both the modal components (local peaks in the −1.0 to +1.0° range) and the monotonic components (linear or sigmoidal dependency on disparity) of the tuning patterns. Values derived from the asymmetric Gaussian fits were used to characterize neurons on a modal × monotonic tuning domain. Points along the modal tuning axis correspond to classic tuned excitatory and inhibitory patterns; points along the monotonic axis correspond to classic near and far patterns. The distribution on this domain was continuous, with the majority of neurons exhibiting a mixed modal/monotonic tuning pattern. The distribution in the modal dimension was shifted toward excitatory patterns, consistent with previous results in other areas. The distribution in the monotonic dimension was shifted toward tuning for crossed disparities (corresponding to stimuli nearer than the fixation plane). This could reflect a perceptual emphasis on objects or object parts closer to the observer. We also found that disparity-tuning strength was positively correlated with orientation-tuning strength and color-tuning strength, and negatively correlated with receptive field eccentricity.

Space-time spectra of complex cell filters in the macaque monkey: A comparison of results obtained with pseudowhite noise and grating stimuli

1994 ◽  
Vol 11 (4) ◽  
pp. 805-821 ◽  
Author(s):  
James P. Gaska ◽  
Lowell D. Jacobson ◽  
Hai-Wen Chen ◽  
Daniel A. Pollen
Keyword(s):  
Spatial Frequency ◽  
Macaque Monkey ◽  
Spike Rate ◽  
Second Order ◽  
Orientation Tuning ◽  
Complex Cell ◽  
Interaction Function ◽  
Tuning Curves ◽  
Complex Cells ◽  
Order Kernel

AbstractWhite noise stimuli were used to estimate second-order kernels for complex cells in cortical area VI of the macaque monkey, and drifting grating stimuli were presented to the same sample of neurons to obtain orientation and spatial-frequency tuning curves. Using these data, we quantified how well second-order kernels predict the normalized tuning of the average response of complex cells to drifting gratings.The estimated second-order kernel of each complex cell was transformed into an interaction function defined over all spatial and temporal lags without regard to absolute position or delay. The Fourier transform of each interaction function was then computed to obtain an interaction spectrum. For a cell that is well modeled by a second-order system, the cell’s interaction spectrum is proportional to the tuning of its average spike rate to drifting gratings. This result was used to obtain spatial-frequency and orientation tuning predictions for each cell based on its second-order kernel. From the spatial-frequency and orientation tuning curves, we computed peaks and bandwidths, and an index for directional selectivity.We found that the predictions derived from second-order kernels provide an accurate description of the change in the average spike rate of complex cells to single drifting sine–wave gratings. These findings are consistent with a model for complex cells that has a quadratic spectral energy operator at its core but are inconsistent with a spectral amplitude model.

scholarly journals Receptive field focus of visual area V4 neurons determines responses to illusory surfaces

2013 ◽  
Vol 110 (42) ◽  
pp. 17095-17100 ◽  
Author(s):  
M. A. Cox ◽  
M. C. Schmid ◽  
A. J. Peters ◽  
R. C. Saunders ◽  
D. A. Leopold ◽  
...  
Keyword(s):  
Receptive Field ◽  
Visual Area ◽  
Area V4 ◽  
Visual Area V4 ◽  
V4 Neurons

Disparity-Selective Neurons in Area V4 of Macaque Monkeys

2002 ◽  
Vol 87 (4) ◽  
pp. 1960-1973 ◽  
Author(s):  
Masayuki Watanabe ◽  
Hiroki Tanaka ◽  
Takanori Uka ◽  
Ichiro Fujita
Keyword(s):  
Receptive Field ◽  
Binocular Disparity ◽  
Temporal Cortex ◽  
Intermediate Stage ◽  
Visual Pathway ◽  
Inferior Temporal Cortex ◽  
Tuning Curves ◽  
Area V4 ◽  
Ventral Visual Pathway ◽  
V4 Neurons

Area V4 is an intermediate stage of the ventral visual pathway providing major input to the final stages in the inferior temporal cortex (IT). This pathway is involved in the processing of shape, color, and texture. IT neurons are also sensitive to horizontal binocular disparity, suggesting that binocular disparity is processed along the ventral visual pathway. In the present study, we examined the processing of binocular disparity information by V4 neurons. We recorded responses of V4 neurons to binocularly disparate stimuli. A population of V4 neurons modified their responses according to changes of stimulus disparity; neither monocular responses nor eye movements could account for this modulation. Disparity-tuning curves were similar for different locations within a neuron's receptive field. Neighboring neurons recorded using a single electrode displayed similar disparity-tuning properties. These findings indicate that a population of V4 neurons is selective for binocular disparity, invariant for the position of the stimulus within the receptive field. The finding that V4 neurons with similar disparity selectivity are clustered suggests the existence of functional modules for disparity processing in V4.

scholarly journals Shape encoding consistency across colors in primate V4

2012 ◽  
Vol 108 (5) ◽  
pp. 1299-1308 ◽  
Author(s):  
Brittany N. Bushnell ◽  
Anitha Pasupathy
Keyword(s):  
Correlation Coefficients ◽  
Shape Selectivity ◽  
Shape Information ◽  
Area V4 ◽  
Neuronal Populations ◽  
Shape Encoding ◽  
Shape Selective ◽  
Different Shapes ◽  
V4 Neurons ◽  
Response Consistency

Neurons in primate cortical area V4 are sensitive to the form and color of visual stimuli. To determine whether form selectivity remains consistent across colors, we studied the responses of single V4 neurons in awake monkeys to a set of two-dimensional shapes presented in two different colors. For each neuron, we chose two colors that were visually distinct and that evoked reliable and different responses. Across neurons, the correlation coefficient between responses in the two colors ranged from −0.03 to 0.93 (median 0.54). Neurons with highly consistent shape responses, i.e., high correlation coefficients, showed greater dispersion in their responses to the different shapes, i.e., greater shape selectivity, and also tended to have less eccentric receptive field locations; among shape-selective neurons, shape consistency ranged from 0.16 to 0.93 (median 0.63). Consistency of shape responses was independent of the physical difference between the stimulus colors used and the strength of neuronal color tuning. Finally, we found that our measurement of shape response consistency was strongly influenced by the number of stimulus repeats: consistency estimates based on fewer than 10 repeats were substantially underestimated. In conclusion, our results suggest that neurons that are likely to contribute to shape perception and discrimination exhibit shape responses that are largely consistent across colors, facilitating the use of simpler algorithms for decoding shape information from V4 neuronal populations.

scholarly journals Receptive field mechanisms of cat X and Y retinal ganglion cells.

1979 ◽  
Vol 74 (2) ◽  
pp. 275-298 ◽  
Author(s):  
J D Victor ◽  
R M Shapley
Keyword(s):  
Receptive Field ◽  
Spatial Frequency ◽  
Frequency Response ◽  
Retinal Ganglion Cells ◽  
Ganglion Cells ◽  
Second Order ◽  
Retinal Ganglion ◽  
First Order ◽  
X Cells ◽  
Y Cells

We investigated receptive field properties of cat retinal ganglion cells with visual stimuli which were sinusoidal spatial gratings amplitude modulated in time by a sum of sinusoids. Neural responses were analyzed into the Fourier components at the input frequencies and the components at sum and difference frequencies. The first-order frequency response of X cells had a marked spatial phase and spatial frequency dependence which could be explained in terms of linear interactions between center and surround mechanisms in the receptive field. The second-order frequency response of X cells was much smaller than the first-order frequency response at all spatial frequencies. The spatial phase and spatial frequency dependence of the first-order frequency response in Y cells in some ways resembled that of X cells. However, the Y first-order response declined to zero at a much lower spatial frequency than in X cells. Furthermore, the second-order frequency response was larger in Y cells; the second-order frequency components became the dominant part of the response for patterns of high spatial frequency. This implies that the receptive field center and surround mechanisms are physiologically quite different in Y cells from those in X cells, and that the Y cells also receive excitatory drive from an additional nonlinear receptive field mechanism.

scholarly journals Presaccadic discrimination of receptive field stimuli by area V4 neurons

2009 ◽  
Vol 49 (10) ◽  
pp. 1227-1232 ◽  
Author(s):  
Tirin Moore ◽  
Mindy H. Chang
Keyword(s):  
Receptive Field ◽  
Area V4 ◽  
V4 Neurons

Orientation and Direction Tuning of Goldfish Ganglion Cells

1989 ◽  
Vol 2 (1) ◽  
pp. 3-13 ◽  
Author(s):  
Joseph Bilotta ◽  
Israel Abramov
Keyword(s):  
Receptive Field ◽  
Spatial Frequency ◽  
Ganglion Cell ◽  
Ganglion Cells ◽  
Receptive Fields ◽  
Orientation Tuning ◽  
Retinal Ganglion ◽  
Spatial Frequencies ◽  
Sinusoidal Gratings ◽  
Direction Tuning

AbstractOrientation and direction tuning were examined in goldfish ganglion cells by drifting sinusoidal gratings across the receptive field of the cell. Each ganglion cell was first classified as X-, Y- or W-like based on its responses to a contrast-reversal grating positioned at various spatial phases of the cell's receptive field. Sinusoidal gratings were drifted at different orientations and directions across the receptive field of the cell; spatial frequency and contrast of the grating were also varied. It was found that some X-like cells responded similarly to all orientations and directions, indicating that these cells had circular and symmetrical fields. Other X-like cells showed a preference for certain orientations at high spatial frequencies suggesting that these cells possess an elliptical center mechanism (since only the center mechanism is sensitive to high spatial frequencies). In virtually all cases, X-like cells were not directionally tuned. All but one Y-like cell displayed orientation tuning but, as with X-like cells, orientation tuning appeared only at high spatial frequencies. A substantial portion of these Y-like cells also showed a direction preference. This preference was dependent on spatial frequency but in a manner different from orientation tuning, suggesting that these two phenomena result from different mechanisms. All W-like cells possessed orientation and direction tuning, both of which depended on the spatial frequency of the stimulus. These results support past work which suggests that the center and surround components of retinal ganglion cell receptive fields are not necessarily circular or concentric, and that they may actually consist of smaller subareas.

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