eye movements Flashcards
what are 2 main afferent paths from the eye
- to LGN in thalamus>V1
2. to sup. Coll.
what are 2 paths from V1
dorsal - where?
ventral - what?
4 functions of eye movements and the 6 movements involved
A. keep eyes still when head moves - 1. VOR and 2. optokinetic reflex B. change what are looking at 3. saccade C. keep an object in fovea 4. pursuit 5. fixation D. change the plane of an object 6. vergence
what are 2 regions involved in vert. and horiz. gaze
- vertical - MLF in midbrain
2. horiz- PPRF in pons
what are 2 parts of the VOR
- direct - move eye to keep in place
2. indirect - via nucleus preposteous to keep eye there once it has moved
what are neural integrators for vert. and horiz. eye movements
- vert - INC -interstitial nucleus of Cajal
2. horiz. - NPH - nucleus prepostus hypoglossi
what is optokinetic reflex
based on visual input instead of head movement - stabilizes head during slow or constant velocity head movements
what is short path of saccadic eye movements
to SC>PPRF for reflexive movement - haven’t seen object
what is long path of saccadic eye movements
V1 to prefrontal for visual memories
what is pathways of saccading right
left frontal eye field>PPRF>split to abducens and left MLF> MLF to CN3 on contra side
what are 2 paths that are added into the pursuit pathway
pontine nucleus signals to the vestibulocerebellum and this goes to the vestibular nucleus
what happens in a lesion to the frontal eye field pathways
get eyes moving away from the hemiparesis
what happens in lesion of PPRF
get eyes moving towards the hemiparesis
what happens to left eye in left MLF lesion when look straight, right, left, converge
straight - okay
right - cannot adduct
left - fine
converge - can adduct because convergence is another level
what is upgaze palsy
cannot look up, but down and horiz. are fine
