How does the ear code sound?
Once sound is sent from the auditory nerve up to the brain, it is processed in two ways: rate-place code, and temporal code. You can think of "rate-place" as the firing rate of neurons within the inner hair cells, and think of "temporal" as the timing in which these firing rates occur.
What is the rate-place code?
Rate-place code is related to the firing rate of neurons within the inner hair cells, due to the stimulation from the incoming sound. Each place on the basilar membrane corresponds to a specific frequency. When a sound wave activates a certain part on the basilar membrane, neurons within the inner hair cells are triggered and send information to the brain through the auditory nerve. With outer hair cell loss, we cannot rely on rate-place coding as much because the system is impaired. Rate-place code is important to our sensitivity in hearing, such as identifying low level sounds. The sound will not be as precise or comprehensible compared to a person with normal outer hair cells.
What is the temporal code?
Temporal coding is related to timing and is a representation of the amount of neurons firing in relation to sound waves. The neurons being stimulated by auditory nerves provide information about the timing and intervals (offset/onset) of the sounds we perceive. Our ability to interpret the timing of auditory neurons being fired gives us the ability to identify frequencies. Even with outer hair cell loss, we still have our temporal coding intact and rely on this function predominantly more than rate-place code to understand sound and speech.
Once sound is sent from the auditory nerve up to the brain, it is processed in two ways: rate-place code, and temporal code. You can think of "rate-place" as the firing rate of neurons within the inner hair cells, and think of "temporal" as the timing in which these firing rates occur.
What is the rate-place code?
Rate-place code is related to the firing rate of neurons within the inner hair cells, due to the stimulation from the incoming sound. Each place on the basilar membrane corresponds to a specific frequency. When a sound wave activates a certain part on the basilar membrane, neurons within the inner hair cells are triggered and send information to the brain through the auditory nerve. With outer hair cell loss, we cannot rely on rate-place coding as much because the system is impaired. Rate-place code is important to our sensitivity in hearing, such as identifying low level sounds. The sound will not be as precise or comprehensible compared to a person with normal outer hair cells.
What is the temporal code?
Temporal coding is related to timing and is a representation of the amount of neurons firing in relation to sound waves. The neurons being stimulated by auditory nerves provide information about the timing and intervals (offset/onset) of the sounds we perceive. Our ability to interpret the timing of auditory neurons being fired gives us the ability to identify frequencies. Even with outer hair cell loss, we still have our temporal coding intact and rely on this function predominantly more than rate-place code to understand sound and speech.