Auditory Brainstem Responses in Two Closely Related Peromyscus Species (Peromyscus leucopus and Peromyscus maniculatus)

The genus Peromyscus has been extensively used as a model for ecological, behavioral, and evolutionary studies. We used auditory brainstem responses (ABRs), craniofacial morphology, and pinna measurements to compare characteristics that could impact the threshold, amplitude, and latency of ABRs in two wild-caught species, P. leucopus and P. maniculatus. We observed significant differences in craniofacial and pinna attributes between species, with P. leucopus exhibiting larger features and bigger overall size compared to P. maniculatus. ABR recordings showed similar hearing thresholds with peak sensitivity between 8 to 46 kHz for both species. We found that amplitude of ABR wave I and IV increased significantly with increasing intensity, while no main effect of species was detected. Latency of wave I and IV significantly decreased with increasing intensity in both species. Finally, we observed longer latencies of the binaural interaction component (BIC) at longer interaural time differences (ITDs) in P. leucopus, while no differences were observed across relative BIC amplitude between species. These results provide additional ABR related data that expands the use of both Peromyscus species as future models for auditory research.