Audiovocal organization in the amygdala forms the neural substrate for adaptive behaviors that include motivational and affective regulation of vocal activity. The first objective of this project is to describe the representation of social calls in the basolateral amygdala. A second objective is to localize the interface between call representation and vocal expression in the amygdala. At present, we know very little of this organization in the mammalian amygdala. The proposed studies will be conducted in mustached bats since this species is highly social and vocal. The auditory system of this species is well developed and well studied. Local field potential recordings combined with single unit recordings from the amygdala will reveal the spatial organization for representing different call types including pitch-shifted call variants. Using statistical procedures, the auditory representation will be tested for an acoustic structure versus motivational value based match. A motivational-value based representation will allow for an aggressive versus affiliative grouping of neurons, whereas an acoustic structure-based organization will conform to the segregation of auditory and/or vocal activity according to acoustic features, e.g., fundamental frequency, pitch, loudness and/or direction of frequency modulations. Call selectivity will also be quantified along the dorso-ventral (lateral to basal nuclei) trajectory at several planes along the anterior-posterior axis within the basolateral amygdala. An acoustic structure to motivational value transformation is expected in auditory-to-vocal mappings within the basolateral amygdala. Therefore, at the end of each recording session, electrical microstimulation will be performed to reveal the patterns of vocal activity represented within the amygdala. Taken together, these data will reveal for the first time whether audiovocal learning and memory, e.g., via fear-conditioning, is embedded within a contingency/motivational-value (reward or pain) based and/or an acoustic- structure based frame-of-reference within the amygdala.
The proposed research will elucidate the functional organization of the neural substrate within the amygdala for nonverbal audiovocal communication, including the vocal expression of affect and the prosodic content in speech. This research will identify the neural signatures for the representation of affiliative versus aggressive calls. The new findings have the potential to help us understand and resolve the neural defects in communication-related social disorders, e.g., stuttering and autism-spectrum disorders. ? ? ?
| Washington, Stuart D; Kanwal, Jagmeet S (2012) Sex-dependent hemispheric asymmetries for processing frequency-modulated sounds in the primary auditory cortex of the mustached bat. J Neurophysiol 108:1548-66 |
| Ma, Jie; Naumann, Robert T; Kanwal, Jagmeet S (2010) Fear conditioned discrimination of frequency modulated sweeps within species-specific calls of mustached bats. PLoS One 5:e10579 |
