A dendrite-autonomous mechanism for direction selectivity in retinal starburst amacrine cells.

ABSTRACT: Detection of image motion direction begins in the retina, with starburst amacrine cells (SACs) playing a major role. SACs generate larger dendritic Ca(2+) signals when motion is from their somata towards their dendritic tips than for motion in the opposite direction. To study the mechanisms underlying the computation of direction selectivity (DS) in SAC dendrites, electrical responses to expanding and contracting circular wave visual stimuli were measured via somatic whole-cell recordings and quantified using Fourier analysis. Fundamental and, especially, harmonic frequency components were larger for expanding stimuli. This DS persists in the presence of GABA and glycine receptor antagonists, suggesting that inhibitory network interactions are not essential. The presence of harmonics indic

SUBMITTER: Hausselt SE 

PROVIDER: S-EPMC1906843 | biostudies-literature | 2007 Jul

REPOSITORIES: biostudies-literature