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Ming Chen, Peichao Li, Shude Zhu, Chao Han, Haoran Xu, Yang Fang, Jiaming Hu, Haidong Lu, Anna W. Roe; Motion boundary response domains in awake monkey V2. Journal of Vision 2012;12(9):1308. doi: https://doi.org/10.1167/12.9.1308.
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© ARVO (1962-2015); The Authors (2016-present)
In the primate visual system, motion information is mainly processed in the dorsal visual pathway (V1 - MT). Recent findings of direction maps in areas V2 and V4, however, suggest that these areas may also play a significant role in motion perception. Perceptually, relative motion is an important source for detection of object boundaries as well as its 3D shape. In this study, we tested the hypothesis that area V2 is involved in detection of motion boundaries and their orientation at a population level.
Monkeys were trained to perform a simple eye fixation task. Cortical activities were imaged through a chronic optical window over the visual areasV1 and V2. A motion boundary was created by two random dot patches within which dots were drifting coherently in opposite directions. By comparing cortical responses to horizontal and vertical motion boundaries, we found that there are domains within V2 that are preferentially activated by specific orientation of the motion boundaries. These orientation domains co-localize with regular luminance orientation domains. In comparison, V1 does not have a clear orientation response pattern to the motion boundaries, although pixel-averaged quantification does indicate some weak response in V1. Results from control stimuli indicate that such differences between V1 and V2 were not due to their differences in spatial frequency preferences and point to a V2 locus of motion boundary detection. Such second-order orientation detection mechanism shares the same functional architectures as the luminance orientation maps in V2.
Meeting abstract presented at VSS 2012
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