The Auditory System. Dr. Kline FSU. What is the physical stimulus for audition?. Sound- vibrations of the molecules in a medium like air. The hearing spectrum for humans is approximately between 20 to 20,000 Hz. 3 basic physical properties of sound. 1. Amplitude: intensity of sound
The stirrup triggers vibrations of the oval window which moves the fluid of the cochlea.
Ear--cochlear nucleus—superior olivary nucleus (medulla)—inferior colliculus (midbrain)—medial geniculate nucleus (Thalamus)—Primary auditory cortex.
If all of these neuron fibers are taken together they may produce a volley of impulses by various fibers that as a whole code the pitch.
1. Low Frequencies are coded by frequency of nerve impulses (up to 50 Hz).
1. We localize low frequencies (to 1500 Hz) by differences in the phase or timing of onset of the sound.