Section 3 part 3 - visual/auditory systems Flashcards
The optic radiations in the temporal lobe transmit info from what part of the visual field?
superior
The optic radiations in the parietal lobe transmit info from what part of the visual field?
inferior
Where do the optic radiations passing through the temporal lobe synapse?
inferior bank of calarine gyrus - lingual gyrus
Where do the optic radiations passing through the parietal lobe synapse?
superior bank of calcarine gyrus - cuneate gyrus
Optic radiations to the hypothalmus control what?
long-term reactions to light
optic radiations to the pretectum control what?
calculates total light entering eye and constricts the pupil in response to light
The pretectal cells have two different destinations, what are they?
cross midline to other EW nucleus
or
project to EW nucleus of same side
preganglionic EW axons project to where? postganglionic axons?
preganglionic fibers travel with the oculomotor nerve to innervate the ciliary ganglion
postganglionic pass to the eye in short ciliary nerves synapse on sphincter pupillae and ciliary body
What do they believe the function of the optic axons to the superior colliculus is?
control rapid orientation of eyes, and body to a visual event
What is the direct response and the consensual response in the pupillary light reflex?
direct - change pupil size in eye that receives light
consensual - opposite eye changes
When light is shone on a person’s eye what normally happens?
both eyes constrict
If the left optic nerve is damaged and light is shone in the left eye (ipsi) which pathways are affected?
NO direct
NO consensual
-neither eye will constrict
If the left optic nerve is damaged and light is shone in the right eye (contra), which pathways are affected ?
BOTH direct and consensual are INTACT
-both eyes will constrict
If the left EW nucleus or the left oculomotor nerve is damaged, and light is shone in the left eye (ipsi), which pathways are affected?
NO direct
consensual is INTACT
right eye will constrict , left eye won’t
If the left EW nucleus or the left oculomotor nerve is damaged, and light is shone in the right eye (contra), which pathways are affected
direct INTACT
NO consensual
right eye will constrict, left eye won’t
If the medial midbrain is damaged aka bilateral pretectal nuclei and/or both EW nuclei, which pathways are affected?
NO direct on either eye
NO consensual on either eye
The vestibulocochlear nerve carries information from where to where??
cochlea to dorsal and ventral cochlear nuclei
(on surface of the inferior cerebellar peduncle - at transition of medulla and pons)
If the left cochlear nerve is damaged, what happens?
left hearing loss
Where do second order auditory neurons cross?
in the caudal pons in the trapezoid body
If you have hearing loss in one ear, where must the damage be?
Either:
- same ear
- same CN8
- same cochlear nuclei
If you have hearing loss in both ears, where is the damage?
bilateral damage in:
- both ears
- brainstem
- temporal lobe
After most auditory info ascends in the lateral lemniscus pathway, what are the next three steps?
inferior colliculus –> (brachium) MGN –>(posterior internal capsule) Heschl’s gyri
Which brodman areas is heschl’s gyrus?
areas 41 and 42
What is the function of heschl’s gyrus?
distinguishes sound patterns
If one heschl’s gyrus is damaged, what is the result?
nothing because each gyrus receives bilateral input
How does the left heschl’s gyrus communicate with the right ?
through the corpus callosum
What does wernicke’s area include?
In the left hemisphere:
- supramarginal gyrus
- posterior portion of superior temporal gyrus
- planum temporale
What three locations would damage lead to inability to understand spoken language?
- both heschl’s gyri
- left auditory cortex
- corpus callosum
What is broca’s area?
Inferior frontal gyrus
-organizes commands for speech
What is broca’s aphasia?
can’t generate speech or write but understand language
What is wernicke’s aphasia?
inability to understand language and speak coherently
