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. This study used auditory brainstem responses (ABRs), craniofacial morphology, and pinna measurements to compare two wild-caught species, Peromyscus leucopus and Peromyscus maniculatus. It was observed that P. leucopus exhibited larger features and bigger overall size compared to P. maniculatus. ABR recordings showed similar hearing thresholds with peak sensitivity between 8 and 46 kHz for both species. There were no significant differences between species for absolute amplitudes of waves IV and I, with significantly higher amplitude ratio of wave IV to wave I in P. leucopus across intensities. There were also species differences (faster wave I in P. maniculatus) and sex differences (faster wave I in female P. leucopus) for absolute latency, which were no longer significant when considering inter-peak latency between waves I and IV. Finally, faster normalized latencies of the binaural interaction component (BIC) were observed in P. maniculatus, while no differences were observed across relative BIC amplitude between species. These results provide additional ABR related data that expand the use of both Peromyscus species as future models for auditory research.