Coding of relative disparity in monkey visual area V4

Umeda, Kazumasa; Tanabe, Seiji; Fujita, Ichiro

doi:10.1167/4.8.589

Cited by 5 publications

(2 citation statements)

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“…Our MT data show that relative disparity signals are not more prominent at the next stage along the dorsal stream, suggesting that relative-disparity-selective V2 neurons may not project to MT. Rather, our data suggest that relative disparity signals are likely to be more prominent in V4, and preliminary results from Umeda et al (2004) support this conjecture. Robust relative disparity signals in V4 may supply critical inputs to neurons in the inferotemporal cortex that signal 3D shape defined by disparity gradients (Janssen et al, 1999(Janssen et al, , 2000a.…”

Section: Cortical Representation Of Relative Disparitysupporting

confidence: 43%

“…This median value was significantly larger than zero (sign test, p Ͻ 0.01), but again there were almost no shifts larger than 0.5. Thus, the lack of robust relative disparity sensitivity in MT, as compared with V2 (Thomas et al, 2002) and V4 (Umeda et al, 2004), does not appear to be related to the stimulus parameters that we have used.…”

Section: Do Mt Neurons Signal Absolute or Relative Disparity?mentioning

confidence: 83%

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Linking Neural Representation to Function in Stereoscopic Depth Perception: Roles of the Middle Temporal Area in Coarse versus Fine Disparity Discrimination

Uka

DeAngelis

2006

Journal of Neuroscience

114

152

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Neurons selective for binocular disparity form the neural substrate for stereoscopic depth perception and are found in several areas of primate visual cortex. Presumably, multiple representations of disparity exist to serve different functions, but the specific contributions of different visual areas to depth perception remain poorly understood. We examine this issue by comparing the contributions of the middle temporal (MT) area to performance of two depth discrimination tasks: a "coarse" task that involves discrimination between absolute disparities in the presence of noise, and a "fine" task that involves discrimination of very small differences in relative disparity between two stimuli in the absence of noise. In the fine task, we find that electrical microstimulation of MT does not affect perceptual decisions, although many individual MT neurons have sufficient sensitivity to account for behavioral performance. In contrast, microstimulation at the same recording sites does bias depth percepts in the coarse task. We hypothesized that these results may be explained by the fact that MT neurons do not represent relative disparity signals that are thought to be essential for the fine task. This hypothesis was supported by single-unit recordings that show that MT neurons signal absolute, but not relative, disparities in a stimulus configuration similar to that used in the fine task. This work establishes a link between the neural representation of disparity in MT and the functional contributions of this area to depth perception.

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Section: Cortical Representation Of Relative Disparitysupporting

confidence: 43%

Section: Do Mt Neurons Signal Absolute or Relative Disparity?mentioning

confidence: 83%

Linking Neural Representation to Function in Stereoscopic Depth Perception: Roles of the Middle Temporal Area in Coarse versus Fine Disparity Discrimination

Uka

DeAngelis

2006

Journal of Neuroscience

114

152

View full text Add to dashboard Cite

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Binocular depth perception and the cerebral cortex

Parker¹

2007

Nat Rev Neurosci

347

259

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Our ability to coordinate the use of our left and right eyes and to make use of subtle differences between the images received by each eye allows us to perceive stereoscopic depth, which is important for the visual perception of three-dimensional space. Binocular neurons in the visual cortex combine signals from the left and right eyes. Probing the roles of binocular neurons in different perceptual tasks has advanced our understanding of the stages within the visual cortex that lead to binocular depth perception.

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Disparity-Tuning Characteristics of Neuronal Responses to Dynamic Random-Dot Stereograms in Macaque Visual Area V4

Tanabe

Doi²,

Umeda³

et al. 2005

Journal of Neurophysiology

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Stereo processing begins in the striate cortex and involves several extrastriate visual areas. We quantitatively analyzed the disparity-tuning characteristics of neurons in area V4 of awake, fixating monkeys. Approximately half of the analyzed V4 cells were tuned for horizontal binocular disparities embedded in dynamic random-dot stereograms (RDSs). Their response preferences were strongly biased for crossed disparities. To characterize the disparity-tuning profile, we fitted a Gabor function to the disparity-tuning data. The distribution of V4 cells showed a single dense cluster in a joint parameter space of the center and the phase parameters of the fitted Gabor function; most V4 neurons were maximally sensitive to fine stereoscopic depth increments near zero disparity. Comparing single-cell responses with background multiunit responses at the same sites showed that disparity-sensitive cells were clustered within V4 and that nearby cells possessed similar preferred disparities. Consistent with a recent report by Hegdé and Van Essen, the disparity tuning for an RDS drastically differed from that for a solid-figure stereogram (SFS). Disparity-tuning curves were generally broader for SFSs than for RDSs, and there was no correlation between the fitted Gabor functions' amplitudes, widths, or peaks for the two types of stereograms. The differences were partially attributable to shifts in the monocular images of an SFS. Our results suggest that the representation of stereoscopic depth in V4 is suited for detecting fine structural features protruding from a background. The representation is not generic and differs when the stimulus is broad-band noise or a solid figure.

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Coding of relative disparity in monkey visual area V4

Cited by 5 publications

References 0 publications

Linking Neural Representation to Function in Stereoscopic Depth Perception: Roles of the Middle Temporal Area in Coarse versus Fine Disparity Discrimination

Linking Neural Representation to Function in Stereoscopic Depth Perception: Roles of the Middle Temporal Area in Coarse versus Fine Disparity Discrimination

Binocular depth perception and the cerebral cortex

Disparity-Tuning Characteristics of Neuronal Responses to Dynamic Random-Dot Stereograms in Macaque Visual Area V4

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