Sparse coding and decorrelation in primary visual cortex during natural vision

Theoretical studies suggest that primary visual cortex (area V1) uses a sparse code to efÞciently represent natural scenes. This issue was investigated by recording from V1 neurons in awake behaving macaques during both free viewing of natural scenes and conditions simulating natural vision. Stimulation of the nonclassical receptive Þeld increases the selectivity and sparseness of individual V1 neurons, increases the sparseness of the population response distribution, and strongly decorrelates the responses of neuron pairs. These effects are due to both excitatory and suppressive modulation of the classical receptive Þeld by the nonclassical receptive Þeld and do not depend critically on the spatiotemporal structure of the stimuli. During natural vision, the classical and nonclassical receptive Þelds function together to form a sparse representation of the visual world. This sparse code may be computationally efÞcient for both early vision and higher visual processing. Although area V1 has been studied for over 40 years, little is known about how V1 en