Brainstem, whole-nerve AP and single-fiber suppression in the gerbil: normative data

Area of Science:

• Auditory Neuroscience
• Neurophysiology
• Psychoacoustics

Background:

• Auditory masking is crucial for understanding auditory perception.
• Brainstem responses (BSRs) and whole-nerve action potential (AP) responses reflect auditory system function.
• Previous studies explored suppression in auditory nerve fibers.

Purpose of the Study:

• To investigate suppression of gerbil brainstem responses (BSRs) and whole-nerve AP responses using forward masking.
• To characterize the suppression areas in relation to BSR and AP tuning curves.
• To compare BSR and AP suppression areas with two-tone rate suppression in single auditory nerve fibers.

Main Methods:

• Utilized a forward masking procedure with a tone-burst probe preceded by a narrow-band masker.
• Introduced a third stimulus (tone burst) presented simultaneously with the masker to modulate suppression.
• Varied the frequency and intensity of the third stimulus to determine BSR suppression areas.

Main Results:

• BSR and AP suppression areas were found to flank the tails and high-frequency sides of BSR tuning curves.
• Suppression area shapes and sizes varied across probe frequencies and individual gerbils.
• The lower boundaries of suppression areas on tuning curve tails remained consistent across conditions.

Conclusions:

• BSR and AP suppression areas exhibit similarities to each other and to two-tone rate suppression in single auditory nerve fibers.
• The findings provide insights into the neural mechanisms underlying auditory masking and frequency tuning.
• Auditory system suppression mechanisms are conserved across different response levels and fiber types.