Sensory Motor Interfacing in Acoustic Behavior of Anurans

SYNOPSIS. Anurans respond to different acoustic signals in a distinct manner. Moreover, acoustic behavior strongly depends on the inner state of the animal and the social context. Neuroanatomical studies as well as extra- and intracellular recordings were carried out to examine the problem of audio-motor interfacing. Acoustic signals are processed in a partly hierarchical and partly distributed manner in the anuran central nervous system. Features are represented in a topographical manner. Auditory maps in the midbrain torus semicircularis are read by a subset of neurons of the laminar and magnocellular subnuclei, which interconnect the auditory pathway and premotor centres. These, in turn, feed into neural networks controlling vocalization, locomotion, or autonomic functions. Our data on the cytoarchitectonic organization and connectivity of the interfacing neurons give rise to a population coding hypothesis which may explain the differential evaluation of acoustic signals. Additionally, immunohistochemical findings reveal strong neuromodulatory and hormonal input, especially onto interfacing neurons, suggesting intense influence on the physiological properties of these cells.