The effect of monaural middle ear destruction on postnatal development of auditory response properties of mouse inferior collicular neurons

Abstract

This study examined the effect of monaural middle ear destruction on postnatal development of auditory response properties of inferior collicular (IC) neurons of the laboratory mouse, Mus musculus. Monaural middle ear destruction was performed on juvenile and adult mice and the auditory response properties of neurons in both ICs were examined 4 weeks thereafter. IC neurons of control mice typically had lower minimum thresholds, larger dynamic ranges and greater Q 10 values than IC neurons of experimental juvenile and adult mice. In experimental mice, neurons in the ipsilateral IC (relative to the intact ear) typically had longer latencies, higher minimum thresholds, and smaller dynamic ranges than neurons in the contralateral IC. In experimental adult mice, neurons in the ipsilateral IC had sharper frequency tuning curves than neurons in the contralateral IC. Clear tonotopic organization was only observed in the IC of control mice and experimental adult mice. However, the correlation of increasing minimum threshold with best frequency was observed for IC neurons in control mice but not in experimental juvenile and adult mice. Possible mechanisms for these different response properties are discussed.