Class Notes (839,081)
Canada (511,183)
Psychology (5,220)
PSYCH 3A03 (56)
Paul Faure (56)

The Neural Code.docx

3 Pages

Course Code
Paul Faure

This preview shows page 1. Sign up to view the full 3 pages of the document.
October 18 , 2013 Psych 3A03: Audition The Neural Code Phase Relation: Stapes and Traveling Wave - Basilar membrane peaks at different frequencies Basilar Membrane is a Bandpass Filter - SPL that is most sensitive to = characteristic frequency Basilar Membrane Motion Summary - Basal end of basilar membrane vibrates best to high frequencies but also responds to low frequencies - Apical end of basilar membrane vibrates only to low frequencies - There is a time lag between stapes motion and movement of apical end of basilar membrane - Greater SPLs cause larger displacement Basilar Membrane: Bank of Bandpass Filters - A given frequency causes a particular region to vibrate maximally: the characteristic frequency (CF) - Adjacent regions, particularly toward the base, also vibrate b.m. but less so than the freq that causes maximum displacement - Higher freqs have little vibration - Lower freqs have more vibration - Plot of SPL versus freq to reach same amplitude of displacement reveal bandpass filter function - 8.35kHz tone is point of maximum displacement.: this point of b.m. is tuned to 8.35kHz - Region were the amplitude is high at 8.35kHz (lower sound level) - Steep roll-off at high frequencies - Gradual roll-off at low frequencies Motion of Basilar Membrane is Nonlinear - Input-output function showing b.m. velocity vs. SPL for 9 & 1 kHz tones. The CF for this region of the b.m. is 9kHz - Motion of basilar membrane is not entirely linear with respect to SPL - Input-output function of membrane velocity shows a compressive nonlinearity at CF: at frequencies off CF, vibration is fairly linear - At characteristic frequency it is non linear - Change is compressive because steepness of curve is shallower - Relationship is more linear at SPL extremes with the CF - Relationship is more linear at frequencies above and below CF - Dynamic range changes in terms of the velocity: becomes compressed at characteristic frequencies - Results in the production of audible distortion products (e.g. harmonics and difference tones) Inner (IHC) and Outer Haircells (OHC) 1. Nucleus 2. Stereocilia 3. Cuticular plate: formed from deiter cells 4. Radial afferent ending (dendrite of type I neuron): take information form the receptor towards the brain  Radial and spinal afferent are both spiral ganglia neurons 5. Lateral efferent ending: come from the brain and go to the cochlea (motor neurons that cause motion) – does not synapse directly in the inner haircells; synapses with the afferent nerve 6. Medial efferent ending 7. Spiral afferent ending (dendrite of type II neuron) - Cell body is based in fluid that is isolated from the cell body of the inner hair cells Stereocilia of Haircells (HC) - Typically three rows that are connected - Connections between the tips of the stereocilia and the body of the previous row - Bridges between rows and within a row -
More Less
Unlock Document

Only page 1 are available for preview. Some parts have been intentionally blurred.

Unlock Document
You're Reading a Preview

Unlock to view full version

Unlock Document

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.