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Exam 1 Saccades questions
See above.
13
Medical
Graduate
06/12/2012

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Cards

Term
Where does VOR and OKN processing occur?
Definition
Cerebellum
Term
What is Flouren's law?
Definition
if a cochlear canal is excited, a slow phase drift towards the opposite side. Nystagmums --> working side; Drift --> broken side
Term
Where do reflexive saccades originate in the brain?
Definition
Superior colliculus
Term
What neurologic stream is shut off during a saccade?
Definition
Parvocellular
Term
In NSUCO (and other saccades), what is an expected amount of dysmetria?
Definition
10% undershoot
Term
Which hemisphere is reading typically processed in ?
Definition
Left
Term
What is the average saccadic latency time?
Definition
150-250 ms
Term
What is the breakdown of the ~250 ms saccadic latency time?
Definition
100 ms = calculate direction and magnitude of voluntary saccade

50 ms = afferent signal reaching cortex

100 ms = actual eye movement
Term
What neurologic centers maintain gaze fixation?
Definition
neural integration in the pons for horizontal fixation in the medial vestibular nucleus and nucleus prepositus hypoglossi

midbrain for vertical fixation by the interstitial nucleus of Cajal (INC) in the midbrain
Term
What are common causes of square wave jerk type saccades?
Definition
basal ganglia dz (Parkinson)

Cerebellar Dz (MS)

Meth

Dyslexia

Psychiatric disorders (meds?)

Strabismic amblyopia
Term
What is damaged when square wave jerks are present?
Definition
Frontal Eye Fields

Superior Colliculus

Central Mesenphalic Reticular Formation
Term
What causes macro square wave jerks?
Definition
GABA fails to inhibit the SC due to substantia nigra pars reticulata failure
Term
What ALWAYS causes true opsoclonus?
Definition
Cerebellar dysfunction
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