Shared Flashcard Set

Details

neuro ch 14
terms
39
Other
Not Applicable
12/16/2005

Additional Other Flashcards

 


 

Cards

Term
primary position
Definition
eye has not rotated along any major axis
Term
abduction
Definition
movement away from the midline
Term
adduction
Definition
movement toward midline
Term
secondary position
Definition
purely vertical or horizontal movement
Term
tertiary position
Definition
oblique movements
Term
conjugate movements
Definition
displace visual axis of both eyes in same direction
Term
electro-oculography
Definition
electrodes placed on eye detect movements
Term
convergence/divergence
Definition
movment of eyes towards each other or away from each other
Term
light lever
Definition
contact lens bearing a small mirror - light beam projected onto eye, and eye movements make the angle of indcidence and reflection change (light lever)
Term
search coil
Definition
coil of fine wire attatched to eye, patient's head in a field coil which is an alternating magnetic field that makes a current run
Term
medial rectus
Definition
adducts
Term
lateral rectus
Definition
abducts
Term
superior rectus
Definition
elevates
Term
inferior rectus
Definition
depresses
Term
superior oblique
Definition
depresses, intorts, and adducts. passes through trochlea
Term
inferior oblique
Definition
extorts, elevates, and abducts
Term
abducens nerve controls
Definition
lateral rectus. also called VIth nerve
Term
trochlear nerve
Definition
superior oblique. (IVth)
Term
oculomotor nerve
Definition
superior, inferior, medial recti and inferior oblique (III)
Term
medial longitudinal fasciculus
Definition
large myelinated tract in the brainstem. provvides low-level coordinating cicuitry.
Term
quick eye movements
Definition
displace image from one part of the retina to another
Term
slow eye movements
Definition
prevent an image from moving on the retina
Term
smooth persuit
Definition
eyes track a target in a smooth, conjugate, deviation
Term
vestibulo-ocular reflex
Definition
automatically produces slow eye movement to counteract the motion of the retinal image due to head movement
Term
gain of the VOR
Definition
angular eye velocity/angular head velocity
Term
optokinetic eye movements
Definition
usually occur in response to movements of the head that move entire visual scene when eye is open. stabilizes image of entire background
Term
nystagmus
Definition
jerking movement of eyes, slow then quick
Term
vestibular and optokinetic nystagmus
Definition
nystagmus that occurs because of the VOR and the optokinetic eye movements
Term
physiological nystygmus
Definition
continuous small movements of the eye
Term
retinal slip
Definition
the movement of an image across the retina expressed as a velocity
Term
position error
Definition
static displacement of the image from the fovea
Term
target velocity
Definition
= eye velocity + retinal slip
Term
flocculus
Definition
cerebellar reigon most involved in smooth persuit
Term
retinal error
Definition
separation of an image from the fovea
Term
motor error
Definition
= target position relative to head - current eye position
Term
burst neurons
Definition
produce intense burst of action potentials during a saccade
Term
where are burst neurons?
Definition
paramedian pontine reticular formation
Term
omnipause neurons
Definition
inhibit burst neurons
Term
frontal eye fields
Definition
broadmann's area 8 - activation of them causes conjugate saccades to the oppposite side. cells in this area discharge prior to saccades to visual targets, but not before "spontaneous" saccades
Supporting users have an ad free experience!