Filtering of Visual Information in the Tectum by an Identified Neural Circuit

Abstract

Small Is Attractive The optic tectum of zebrafish larvae is required for the detection, tracking, and capture of small, highly motile prey. Del Bene et al. (p. 669 ) applied a combination of optical, genetic, and pharmacological tools to investigate how neural circuits in the optic tectum filter out low-frequency visual information. Most tectal neurons were tuned to respond selectively to small, moving objects in the fish's visual environment and responded very poorly to large stimuli. This spatial filtering mechanism depended on the activity of a small population of GABAergic, inhibitory interneurons at the tectal surface. Inactivation or destruction of these interneurons removed the size selectivity of deeper neurons and the zebrafish lost their ability to catch prey.