Characteristics of auditory brainstem responses in ground squirrels.

Auditory brainstem responses (ABRs) were characterized at 37 degrees C in ground squirrels (Citellus lateralis) which were implanted with recording screws to record ABRs, and a thermistor to record brain temperature. After two weeks ground squirrels were reanesthetized and tone pips and clicks were delivered through a TDH-49 headphone. Recorded ABRs were found to vary in a predictable manner as a function of stimulus frequency and intensity. At intensities above 50 dB SPL, ABRs could be recorded over the range tested (2-32 kHz). An 8 kHz tone pip was the best frequency for recording ABRs at the lowest stimulus intensities. Latencies decreased as stimulus frequencies increased from 4 kHz to 32 kHz.