Characteristics of auditory brainstem responses in ground squirrels

Area of Science:

• Neuroscience
• Auditory Neuroscience
• Mammalian Physiology

Background:

• Auditory brainstem responses (ABRs) are crucial for assessing auditory pathway function.
• Understanding ABRs in hibernating mammals like ground squirrels provides insights into auditory processing under varying physiological conditions.

Purpose of the Study:

• To characterize auditory brainstem responses (ABRs) in ground squirrels (Citellus lateralis) at a physiologically relevant temperature (37°C).
• To determine the influence of stimulus frequency and intensity on ABR characteristics in this species.

Main Methods:

• Ground squirrels were surgically implanted with recording screws for ABRs and a thermistor for brain temperature monitoring.
• After a two-week recovery period, animals were reanesthetized, and tone pips and clicks were presented via headphones.
• ABRs were recorded and analyzed in relation to stimulus frequency (2-32 kHz) and intensity (dB SPL).

Main Results:

• Auditory brainstem responses (ABRs) exhibited predictable variations with stimulus frequency and intensity.
• ABRs were detectable above 50 dB SPL across the tested frequency range (2-32 kHz).
• An 8 kHz tone pip proved most effective for eliciting ABRs at lower stimulus intensities, and latencies decreased with increasing frequencies from 4 kHz to 32 kHz.

Conclusions:

• Auditory brainstem responses in ground squirrels are sensitive to sound frequency and intensity at 37°C.
• These findings establish a baseline for ABR characterization in ground squirrels, relevant for auditory research in mammals.
• The study highlights the frequency-dependent nature of ABR latencies in this species.