The first specific aim concerns the functional organization of disparity tuned cells in monkey visual cortex. The primary approach will be to make long penetrations through V1, V2, and V3/V3A, quantitatively testing disparity sensitivities and correlating those properties with cortical layer and cytochrome oxidase compartments. In V1 the principal aim will be to refine the current view that most disparity sensitive neurons are found in layer 4B by examining deeper layers, which are likely to contain other disparity sensitive neurons, and by examining the distribution relative to the location of cytochrome oxidase stripes. In V2 the experiments will pursue the observation that the cytochrome oxidase stripes are functionally heterogeneous, and will explore whether neurons with different disparity preferences are grouped or clustered in different regions within a stripe. Recordings in V3 will follow up on observations of clustering of different types of disparity preferences by looking for a columnar organization. Besides the recordings, injections of tracers will be made into V2 and V3 to show the organization of connections between regions with established properties.
The second aim will address how disparity sensitivity is associated with other response properties in individual neurons.Efforts will focus on color, motion, orientation, and responses to random dot stereograms. The question of the relationship between disparity sensitivity and color, motion and orientation is important, because there are several lines of evidence that suggest that disparity sensitivity may be preferentially associated with motion processing, and less with color sensitivity. Conclusive data on this point will help clarify the extent to which these properties are segregated.
The third aim will examine disparity sensitivity in visually naive animals.
The final aim i s to learn whether squirrel monkeys, which lack ocular dominance columns, show stereopsis in their evoke potentials and optokinetic reflexes.
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| Livingstone, M S; Tsao, D Y (1999) Receptive fields of disparity-selective neurons in macaque striate cortex. Nat Neurosci 2:825-32 |
| Livingstone, M S (1998) Mechanisms of direction selectivity in macaque V1. Neuron 20:509-26 |
| Livingstone, M S (1996) Oscillatory firing and interneuronal correlations in squirrel monkey striate cortex. J Neurophysiol 75:2467-85 |
| Livingstone, M S (1996) Ocular dominance columns in New World monkeys. J Neurosci 16:2086-96 |
| Livingstone, M S; Nori, S; Freeman, D C et al. (1995) Stereopsis and binocularity in the squirrel monkey. Vision Res 35:345-54 |
