Stereoscopic Processing of Absolute and Relative Disparity in Human Visual Cortex

Neri, Peter; Bridge, Holly; Heeger, David J.

doi:10.1152/jn.01042.2003

Cited by 172 publications

(188 citation statements)

References 87 publications

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“…Second, there is preliminary evidence showing that V4 neurons encode relative disparity , whereas MT neurons encode absolute disparity (Uka and DeAngelis, 2002). This has been confirmed by a functional magnetic resonance imaging study as well (Neri et al, 2004). The fact that both humans and monkeys are much more sensitive to relative compared with absolute disparity implies that the representation of neurons in the ventral pathway is closer to perception.…”

Section: The Role Of Disparity-selective Neurons In the Ventral Visuamentioning

confidence: 71%

Neural Correlates of Fine Depth Discrimination in Monkey Inferior Temporal Cortex

Uka¹,

Tanabe²,

Watanabe³

et al. 2005

J. Neurosci.

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Binocular disparity is an important visual cue that gives rise to the perception of depth. Disparity signals are widely spread across the visual cortex, but their relative role is poorly understood. Here, we addressed the correlation between the responses of disparity-selective neurons in the occipitotemporal (ventral) visual pathway and the behavioral discrimination of stereoscopic depth. We recorded activity of disparity-selective neurons in the inferior temporal cortex (IT) while monkeys were engaged in a fine stereoscopic depth discrimination (stereoacuity) task. We found that trial-to-trial fluctuations in neuronal responses correlated with the monkey's perceptual choice. We suggest that disparity signals in the IT, located in the ventral visual pathway, are functionally linked to the discrimination of fine-grain depth.

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Section: The Role Of Disparity-selective Neurons In the Ventral Visuamentioning

confidence: 71%

Neural Correlates of Fine Depth Discrimination in Monkey Inferior Temporal Cortex

Uka¹,

Tanabe²,

Watanabe³

et al. 2005

J. Neurosci.

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“…This is in contrast to area MT, in which microstimulation and inactivation had no effects on decisions about fine disparity (Uka and DeAngelis, 2006;Chowdhury and DeAngelis, 2008). Another contrast between V4 and MT is the degree to which neurons are selective for relative disparity between adjacent visual features; a substantial proportion of V4 neurons are selective for relative disparity between the center and surround of concentric stimuli whereas virtually all MT neurons are not (Neri et al, 2004;Uka and DeAngelis, 2006;Umeda et al, 2007; for the selectivity of MT neurons to another type of relative disparity, see Krug and Parker, 2011). The two seemingly independent contrasts may not just be a coincidence, but the result of learning.…”

Section: Roles Of Area V4 In Stereopsismentioning

confidence: 77%

Neural Activity in Cortical Area V4 Underlies Fine Disparity Discrimination

Shiozaki

Tanabe²,

Doi³

et al. 2012

J. Neurosci.

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Primates are capable of discriminating depth with remarkable precision using binocular disparity. Neurons in area V4 are selective for relative disparity, which is the crucial visual cue for discrimination of fine disparity. Here, we investigated the contribution of V4 neurons to fine disparity discrimination. Monkeys discriminated whether the center disk of a dynamic random-dot stereogram was in front of or behind its surrounding annulus. We first behaviorally tested the reference frame of the disparity representation used for performing this task. After learning the task with a set of surround disparities, the monkey generalized its responses to untrained surround disparities, indicating that the perceptual decisions were generated from a disparity representation in a relative frame of reference. We then recorded single-unit responses from V4 while the monkeys performed the task. On average, neuronal thresholds were higher than the behavioral thresholds. The most sensitive neurons reached thresholds as low as the psychophysical thresholds. For subthreshold disparities, the monkeys made frequent errors. The variable decisions were predictable from the fluctuation in the neuronal responses. The predictions were based on a decision model in which each V4 neuron transmits the evidence for the disparity it prefers. We finally altered the disparity representation artificially by means of microstimulation to V4. The decisions were systematically biased when microstimulation boosted the V4 responses. The bias was toward the direction predicted from the decision model. We suggest that disparity signals carried by V4 neurons underlie precise discrimination of fine stereoscopic depth.

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“…Recent results from human fMRI (Neri et al, 2004) also support this hypothesis, which should be amenable to direct tests in the monkey. However, not all data are consistent with this simple view (see also Neri, 2005).…”

Section: Cortical Representation Of Relative Disparitymentioning

confidence: 77%

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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Stereoscopic Processing of Absolute and Relative Disparity in Human Visual Cortex

Cited by 172 publications

References 87 publications

Neural Correlates of Fine Depth Discrimination in Monkey Inferior Temporal Cortex

Neural Correlates of Fine Depth Discrimination in Monkey Inferior Temporal Cortex

Neural Activity in Cortical Area V4 Underlies Fine Disparity Discrimination

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

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