Neurons in the bat auditory cortex encode class and complexity of future vocalizations.

Vocal production is a complex behavior across the animal kingdom that relies on coordinated motor and auditory networks. However, the contribution of sensory areas in vocal control remains poorly understood. Here, we investigated vocalization-related activity in a major auditory processing area in the mammalian brain, the auditory cortex. We recorded neuronal spike rates in an audio-vocal specialist, the bat Carollia perspicillata, which emits vocalizations to echolocate and for social communication. We found distinct spike patterns encoding echolocation and communication calls several hundred milliseconds before vocal onset. Neuronal activity not only contained information about the vocalization category, but also reflected temporal complexity, specifically the syllable amount in a communication sequence. These vocalization-specific firing patterns were dependent on the neurons' frequency receptive field. Our results indicate that single neurons in the auditory cortex not only process acoustic information but also encode the class and temporal structure of future vocal output.