Characterization of the Brainstem Auditory Evoked Potential (BAEP) in the Grey Short-tailed Opossum (Monodelphis Domestica)

Abstract

Brainstem auditory evoked potentials (BAEP) have been measured and characterized in the marsupial Monodelphis domesticain response to toneburst stimulation. Five peaks are usually identified. The BAEP occurs within a time window of 5 ms starting 1.2 ms after onset of stimulation. Latencies decrease with increasing stimulus level at a rate of about −11 μs/dB. At high stimulus frequencies latencies are shorter than with lower frequencies and shorten at a rate of about −0.2 ms/octave.

The wave pattern changes in dependence on stimulus frequency and stimulus level. An additional peak between peaks ii and iii occurs for frequencies above 12 kHz at stimulus levels well above threshold.

Key Words:

• Auditory evoked potential
• Auditory brainstem
• Marsupial
• Evolution