| Description |
The way the auditory system processes the pitch of a sound has been studied by measuring brain activity in response to stimuli that have clear acoustic cues for pitch. These auditory-evoked potentials (i.e., the frequency following response [FFR]) describe the encoding of pitch by the auditory brainstem; however, pitch encoding by the human auditory nerve has not been well established. An understanding of the neural coding of pitch by the auditory nerve is essential because the auditory nerve forms the foundation of all auditory information sent to the brain. Neural coding of acoustic cues associated with pitch for the human auditory nerve was measured for normal-hearing young adults who were native English speakers. These measurements involved obtaining recordings for the compound action potential (CAP) in response to three dynamic stimuli (up-sweep, down-sweep, and mix). CAP results were compared to auditory evoked potentials associated with brainstem activity (FFR). Results support the hypothesis that the auditory nerve is sensitive to acoustic pitch cues, and that this sensitivity is similar to that of the brainstem. Future work is needed to determine if the encoding of dynamic pitch by the auditory nerve is enhanced in certain subject populations (i.e., native vs. non-native speakers of tonal languages, musicians vs. non-musicians), as has been observed for the auditory brainstem. |
