Simultaneous development and periodic clustering of simple and complex cells in visual cortex

Neurons in the primary visual cortex (V1) are often classified as simple or complex cells, but it is debated whether they are discrete hierarchical classes of neurons developing sequentially, or if they represent a continuum of variation within a single class of cells developing simultaneously. Herein, we show that simple and complex cells may arise simultaneously from the universal process of retinal development. From analysis of the cortical receptive fields in cats, we show evidence that simple and complex cells originate from the periodic variation of ON-OFF segregation in the feedforward projection of retinal mosaics, by which they organize into periodic clusters in V1. Our key prediction that clusters of simple and complex cells correlate topographically with orientation maps was confirmed by data in cats. Our results suggest that simple and complex cells are not two distinct neural populations but arise from common retinal afferents, simultaneous with orientation tuning.\n\nHighlightsO_LISimple and complex cells arise simultaneously from retinal afferents.\nC_LIO_LISimple/complex cells are organized into periodic clusters across visual cortex.\nC_LIO_LISimple/complex clusters are topographically correlated with orientation maps.\nC_LIO_LIDevelopment of clustered cells in V1 is explained by the Paik-Ringach model.\nC_LI