Measuring the Auditory Brainstem Response in Mice

Place an anesthetized mouse inside a soundproof box to record precise hearing thresholds.

Insert a needle electrode under the skin at the center of the head and another electrode just behind the ear.

Place a ground electrode near the tail.

Position a speaker in front of the mouse’s ear with the electrode. 

Set the desired parameters, such as frequency and intensity, and then apply acoustic stimuli.

The inner ear receives the acoustic stimuli and converts them into electrical signals that travel via the auditory nerve to the brainstem.

Electrodes detect the auditory brainstem response, or ABR, which is recorded as a waveform. 

Measure ABR under a series of desired stimulus intensities. 

Record the ABR threshold, which is the minimum stimulus intensity required to generate a brain response characterized by the appearance of wave V.

Use a commercial ABR testing system specifically designed for small animals for ABR measurements, and maintain the animal under general anesthesia. Place 12 millimeter subdermal needle electrodes at the vertex, behind the pinna of the left ear and back near the tail to measure the hearing threshold.

After placing the speaker one centimeter away from the animal's left ear, present acoustic stimuli using the speaker. Choose sine wave for the stimuli and 10K for the window scale. Turn the frequency knob to obtain the desired frequency of the acoustic stimuli.

Adjust the stimulus intensity by turning the AMLP knob on the function generator. Obtain the desired stimulus intensity by turning the AMLP knob to a suitable voltage calculated from calibration. Collect the ABR measurements under a series of stimulus intensities from 10 to 100 decibels SPL with a 10 decibel step size. Mark the minimum stimulus intensity level that could give rise to a discernible wave V as the ABR threshold.