SYNTAX PROCESSING BY AUDITORY CORTICAL-NEURONS IN THE FM-FM AREA OF THE MOUSTACHED BAT PTERONOTUS-PARNELLII

Syntax denotes a rule system that allows one to predict the sequencing of communication signals. Despite its significance for both human spe ech processing and animal acoustic communication, the representation o f syntactic structure in the mammalian brain has not been studied elec trophysiologically at the single-unit level. In the search for a neuro nal correlate for syntax, we used playback of natural and temporally d estructured complex species-specific communication calls-so-called com posites-while recording extracellularly from neurons in a physiologica lly well defined area (the FM-FM area) of the mustached bat's auditory cortex. Even though this area is known to be involved in the processi ng of target distance information for echolocation, we found that unit s in the FM-FM area were highly responsive to composites. The finding that neuronal responses were strongly affected by manipulation in the time domain of the natural composite structure lends support to the hy pothesis that syntax processing in mammals occurs at least at the leve l of the nonprimary auditory cortex.