Unit 3 (Auditory Pathways) Flashcards
Lateral Lemniscus
fiber tracts in brainstem that interconnect cochlear nucleus to inferior colliculus in midbrain.
Inferior Colliculus
in midbrain - additional coding of time and intensity differences, receives ipsilateral and contra-lateral input.
Medial Geniculate Body
In Thalamus: all information must pass through these nuclei on the way to the auditory cortex via the corona radiata.
Auditory Cortex
includes primary Area known as Heschl’s Gyrus and association areas that interpret the information received in the primary area.
Spoken language is processed in Wenicke’s area in the left hemisphere.
-information from speech at the right ear goes directly to left hemisphere.
(vice versa)–> how do we process that info without wernicke’s area on right side?
Info has to go back to left hemisphere for processing which is a longgg pathway. –> basis for the right ear advantage.
Has multiple layers with tonotopic maps
forms 3D reps of sound in space
specialized neurons respond to changes in auditory stimuli
receives info about low frequencies via periodicity (phase locking) of neural firings from lower levels of system.
summary of auditory pathways
The cortical areas use “Ipsilateral and contralateral temporal and spectral information extracted at earlier processing stages” for perceiving environmental sounds and processing speech.
Superior Olivary Complex
IN the PONS
The SOC is the lowest level place in the CANS pathways where the neurons receive input from both ears. Therefore, it is the first stage of coding binaural (two ear) information in the CANS.
First place where info from both ears is integrated.
Cochlear Nucleus
IN the PONS. Receives input from ipsilateral cochlea only.
Divided into several sub-nuclei, each of which has tonotopic organization.
Has different types of fibers with differing response patterns.
Middle Ear Muscle Reflex
an involuntary contraction of the middle ear muscles in response to loud sounds. It’s also known as the acoustic reflex.
