Quantitative Analysis of the Responses of V1 Neurons to Horizontal Disparity in Dynamic Random-Dot Stereograms

• Published in: Journal of neurophysiology Vol. 87; no. 1; pp. 191 - 208
• Main Authors: Prince, S.J.D, Pointon, A. D, Cumming, B. G, Parker, A. J
• Format: Journal Article
• Language: English
• Published: United States Am Phys Soc 01-01-2002
• Subjects: Animals; Macaca mulatta; Models, Neurological; Neurons - physiology; Normal Distribution; Orientation - physiology; Photic Stimulation - methods; Predictive Value of Tests; Sensitivity and Specificity; Vision Disparity - physiology; Vision, Binocular - physiology; Visual Cortex - cytology; Visual Cortex - physiology; Wakefulness
• ISSN: 0022-3077; 1522-1598
• DOI: 10.1152/jn.00465.2000

University Laboratory of Physiology, Oxford OX1 3PT, United Kingdom
Prince, S.J.D.,
A. D. Pointon,
B. G. Cumming, and
A. J. Parker.
Quantitative Analysis of the Responses of V1 Neurons to
Horizontal Disparity in Dynamic Random-Dot Stereograms. J. Neurophysiol. 87: 191-208, 2002. Horizontal disparity tuning for dynamic random-dot stereograms was
investigated for a large population of neurons ( n  = 787) in V1 of the awake macaque. Disparity sensitivity was quantified using a measure of the discriminability of the maximum and minimum points on the disparity tuning curve. This measure and others revealed
a continuum of selectivity rather than separate populations of
disparity- and nondisparity-sensitive neurons. Although disparity sensitivity was correlated with the degree of direction tuning, it was
not correlated with other significant neuronal properties, including
preferred orientation and ocular dominance. In accordance with the
Gabor energy model, tuning curves for horizontal disparity were
adequately described by Gabor functions when the neuron's orientation
preference was near vertical. For neurons with orientation preferences
near to horizontal, a Gaussian function was more frequently sufficient.
The spatial frequency of the Gabor function that described the
disparity tuning was weakly correlated with measurements of the spatial
frequency and orientation preference of the neuron for drifting
sinusoidal gratings. Energy models make several predictions about the
relationship between the response rates to monocular and binocular dot
patterns. Few of the predictions were fulfilled exactly, although the
observations can be reconciled with the energy model by simple
modifications. These same modifications also provide an account of the
observed continuum in strength of disparity selectivity. A weak
correlation between the disparity sensitivity of simultaneously
recorded single- and multiunit data were revealed as well as a weak
tendency to show similar disparity preferences. This is compatible with
a degree of local clustering for disparity sensitivity in V1, although
this is much weaker than that reported in area MT.