Hair cells in the cochlea can code sound intensity via the amount of neurotransmitter they release. Higher sound levels result in more neurotransmitter release and in turn to higher firing rates in the spiral ganglion cells of the auditory nerve.
How is the intensity of sound encoded?
Within the linear portion of a rate-level function between threshold and saturation, neural firing rate is correlated with sound level. Therefore, sound intensity is encoded in the firing rate by auditory afferents. This firing rate is sent to the fish brain for processing to extract the sound intensity information.
How does the auditory system process intensity?
All auditory nerve fibers exhibit an increasing bandwidth with increasing intensity, resulting in a filter shape resembling a “V” when response is plotted as a function of both intensity and frequency. Many central auditory neurons also share this response characteristic, even in auditory cortex.
How does the ear code for different frequencies of sound?
The cochlea analyzes sound frequencies (distinguishes pitch) by means of the basilar membrane, which exhibits different degrees of stiffness, or resonance, along its length. The analysis of sound frequencies by the basilar membrane.
How does the auditory system encode location?
Like the monocular and binocular cues that provided information about depth, the auditory system uses both monaural (one-eared) and binaural (two-eared) cues to localize sound. Each pinna interacts with incoming sound waves differently, depending on the sound’s source relative to our bodies.
How do we process auditory information?
Many small neurons located in the brain are responsible for the processing of auditory information. By passing through various auditory pathways, the signals are decoded into sounds that we are familiar with and make sense to us.
How does the cochlea code sound frequency?
When sound pressure is transmitted to the fluids of the inner ear by the stapes, the pressure wave deforms the basilar membrane in an area that is specific to the frequency of the vibration. In this way, higher frequencies cause movement in the base of the cochlea, and deeper frequencies work at the apex.
What is auditory coding?
Traditional views describe auditory coding in terms of spectral features, such as frequency, intensity and phase, that are estimated from the signal. This perspective focuses on the properties and response of the system rather than its purpose.