Scalp-recorded auditory brainstem responses (ABRs) in small animals offer a non-invasive way to assess auditory system function. While ABRs typically focus on fast waves within the first 10 ms after stimulus onset, the method can be modified to detect slower cortical auditory evoked potentials (CAEPs). Although CAEPs have not been previously described in bats, they may offer a useful non-invasive tool for studying cortical processing. Here, we describe two late peaks in the bat auditory evoked potential waveform that appear cortical in origin. The first wave (P1) peaked at 23 ms and showed the same onset (∼10 ms) and duration (∼30 ms) as ensemble neuronal activity in the auditory cortex under matched conditions. A second, smaller wave (P2) peaked at 37 ms, consistent with response timing in the frontal auditory field (FAF), a secondary auditory region. Both peaks varied in amplitude and timing depending on acoustic stimulus properties. Notably, P1 amplitude was reduced at presentation rates above 8 Hz, mirroring cortical forward suppression. These findings demonstrate that robust CAEPs can be non-invasively recorded in bats and carry information about the nature of the stimulus.
Fouhy et al. (2025) studied this question.