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RT Pramod, SP Arun; Does symmetry have a special status in single neurons?. Journal of Vision 2017;17(10):33. doi: https://doi.org/10.1167/17.10.33.
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© ARVO (1962-2015); The Authors (2016-present)
Symmetry is a salient global attribute: it is easy to detect, remember and influences fundamental visual processes such as recognition and segmentation. Yet we know very little about how symmetry is represented in neurons. To address this issue, we recorded from single neurons in the monkey inferior temporal (IT) cortex using shapes made of two arbitrary parts connected by a stem. Shapes made with two identical parts were symmetric while those with different parts were asymmetric. We tested the same shapes oriented vertically and horizontally to characterize mirror symmetry about both axes. Using these shapes we asked whether symmetric objects had any special status at the neural level that would explain their special status at the behavioural level. Our main findings were similar for horizontal and vertical objects: (1) Symmetric objects did not evoke significantly stronger neural responses compared to asymmetric objects; (2) Neural responses to the whole object were explained as a linear sum of the part responses, with no special deviation for symmetric objects; (3) Neural responses to symmetric objects elicited no greater nonlinear interactions between parts compared to asymmetric objects and (4) The sole distinguishing characteristic of symmetric objects was that they were more distinct from each other compared to equivalent asymmetric objects. This distinctiveness is a straightforward outcome of part summation but explain a number of observations regarding symmetry in perception. We propose that symmetry becomes special in perception due to generic computations at the neural level.
Meeting abstract presented at VSS 2017
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