Representation of vocalizations in the frontal auditory field and the dorsal auditory cortex of bats

Abstract

In bats, which express a complex vocal repertoire and are considered vocal learners, the frontal auditory field (FAF) is supposedly placed in a frontal cortico-striatal network for vocal–motor control. The FAF receives input from the auditory cortex (AC) and other auditory nuclei via multiple pathways. However, not much is known about the transition of information on vocalizations from the AC to the FAF. The bat AC consists of different subfields, among which the dorsal fields (dAC) are characterized by precise coding of the temporal envelope of vocalizations. The dAC should, therefore, be a major source of auditory feedback information about self-produced or perceived vocalizations to the FAF. Our study aimed to investigate the specificity of encoding for different types of vocalizations in FAF and dAC neurons. Using extracellular recordings in anesthetized Phyllostomus discolor, we describe basic response properties in both cortical areas and compare responses to different types of prerecorded vocalizations. The specificity of encoding for different behaviorally relevant call categories and single calls was higher in dAC than in FAF neurons, both in terms of temporal firing patterns and response strength. These findings highlight the importance of the dAC in the neural network for control of vocal communication in bats.