Spatial structure and symmetry of simple-cell receptive fields in macaque primary visual cortex.
I present measurements of the spatial structure of simple-cell receptive fields in macaque primary visual cortex (area V1). Similar to previous findings in cat area 17, the spatial profile of simple-cell receptive fields in the macaque is well described by two-dimensional Gabor functions. A population analysis reveals that the distribution of spatial profiles in primary visual cortex lies approximately on a one-parameter family of filter shapes. Surprisingly, the receptive fields cluster into even- and odd-symmetry classes with a tendency for neurons that are well tuned in orientation and spatial frequency to have odd-symmetric receptive fields. The filter shapes predicted by two recent theories of simple-cell receptive field function, independent component analysis and sparse coding, are compared with the data. Both theories predict receptive fields with a larger number of subfields than observed in the experimental data. In addition, these theories do not generate receptive fields that are broadly tuned in orientation and low-pass in spatial frequency, which are commonly seen in monkey V1. The implications of these results for our understanding of image coding and representation in primary visual cortex are discussed.
Ringach
Dario L
DL
Department of Neurobiology, Psychology, and Brain Research Institute, University of California, Los Angeles, California 90095, USA. dario@ucla.edu
D000818:Animals; D008252:Macaca fascicularis / Q000033:anatomy & histology* / Q000502:physiology*; D008959:Models, Neurological; D009474:Neurons / Q000502:physiology*; D014793:Visual Cortex / Q000166:cytology* / Q000502:physiology*