A profile of auditory forebrain connections and circuits

Abstract

Establishing rules for auditory information processing requires knowledge of the physiology of the neurons, their connections, and of how local circuits shape signals. When available, as in the cochlear nucleus (Cant and Benson 2003), such profiles underlie plausible models of receptive field (RF) genesis (Davis and Young 2000), serial information transfer (Smith et al. 1993), and feature detection (Nelken 2002). Progress in this endeavor in the medial geniculate body (MGB) and auditory cortex (AC) since 1990 is the subject of this review, and it is prerequisite to understanding how auditory thalamic (Senatorov and Hu 2002), cortical (de Ribaupierre 1997; Rouiller and Welker 2000), and subcortical sites (Winer 2006) interact. A second theme is the function of massive, focal, and precise corticocortical (Lee and Winer 2005) and corticofugal (Winer 2006) projections. The emerging picture of multiple ascending and descending pathways with intricate convergence and divergence patterns (Smith and Spirou 2002) and robust interneuronal substrates for modulation (Huang et al. 1999) is at odds with more serial models of information flow (Brandner and Redies 1990). Each section summarizes views prevailing circa 1990, then assesses subsequent studies in cat, rodents, bats, and primates.