Combination-sensitive neurons in the central nucleus of inferior colliculus of the house mouse Mus musculus

Abstract

tion in this analysis. The goal of the present work was to reveal mechanisms of spectral processing of complex communicative signals by neurons of the central nucleus of inferior colliculus.This work evaluates extracellular activity of single neurons of the central nucleus of the house mouse inferior colliculus, evoked by call of dis-comfort from repertoire of early ontogeny of the mouse pups, so called “wriggling call,” its model reproducing harmonic structure of natural call and its frequency components. The wriggling call is a nest call of discomfort of mouse pups. It in-duces the instinctive maternal behavior—care of pups, building of nest, and a change of the mater-nal body position during lactation [7]. The main features of the call are its low frequency range (the main energy is concentrated between 2 and 15 kHz) and the pronounced harmonic structure (the call is formed by three major equally-powered harmonics located at 5, 10, and 15 kHz). Neu-ral responses to the wriggling call model, natural wriggling call, and its components were compared with organization of neuronal frequency receptive fields.The study was carried out on females of F1 hy-brids of CBA and C57BL/6 strains at the age of 8–15 weeks. Anesthesia was performed by intra-The most important function of the auditory system is processing of communicative acoustic signals. However, how analysis of communica-tive signals occurs in the brain auditory centers re-mains to be elucidated and, moreover, we do not know what principles underlie the communicative signal discrimination by the auditory system from the diversity of complex sounds. Studies of neuro-nal mechanisms of the analysis of species-specific signals were carried out predominantly in the fore-brain auditory centers of the acoustically special-ized objects [1–3]. At the same time, numerous ascending, descending, and commissural connec-tions of neurons of the midbrain auditory center, the inferior colliculus, structural orderliness of its central nucleus, location of information about var-ious features of auditory signals, high variability of neuronal response patterns allow suggesting that this structure has necessary prerequisites for en-coding of communicative signals [4]. However, so far, there are only occasional works showing selec-tivity of neuronal responses in the central nucleus of the bat inferior colliculus to species-specific signals [5, 6], while neurophysiologic mechanisms of analysis of communicative signals at the level of midbrain auditory neurons remain practically not studied. Much less studied is neuronal specializa-