Do retinal ganglion cells project natural scenes to their principal subspace and whiten them?

TL;DR

This study investigates whether retinal ganglion cells process natural scenes by projecting them onto their principal subspace and whitening the stimuli, providing insights into early visual processing mechanisms.

Contribution

The paper provides empirical evidence on how retinal ganglion cells encode natural scenes, supporting the idea that they transmit only the top principal components of the stimuli.

Findings

Ganglion cell firing rates are less correlated than natural scenes.

Power spectrum of ganglion cells decays less steeply, not fully flattened.

Only the top principal components of stimuli are transmitted.

Abstract

Several theories of early sensory processing suggest that it whitens sensory stimuli. Here, we test three key predictions of the whitening theory using recordings from 152 ganglion cells in salamander retina responding to natural movies. We confirm the previous finding that firing rates of ganglion cells are less correlated compared to natural scenes, although significant correlations remain. We show that while the power spectrum of ganglion cells decays less steeply than that of natural scenes, it is not completely flattened. Finally, we find evidence that only the top principal components of the visual stimulus are transmitted.