Shared Flashcard Set

Details

Control of Eye Movement
N/A
41
Anatomy
Graduate
04/21/2012

Additional Anatomy Flashcards

 


 

Cards

Term
What is the small area of the eye that is responsible for high visual resolution?
Definition
The fovea
Term
What is the function of the lateral rectus? How is it tested?
Definition
Abduction, tested by looking lateral
Term
What is the function of the medial rectus? How is it tested?
Definition
Adduction, tested by looking medial
Term
What is the function of the superior rectus? How is it tested?
Definition
Primarily elevation, also causes intorsion and adduction. Tested by looking out then up
Term
What is the function of the inferior rectus? How is it tested?
Definition
Primarily depression, also causes extorsion and adduction. Tested by looking out and then down
Term
What is the function of the superior oblique? How is it tested?
Definition
Primarily intorsion, also causes depression and abduction. Tested by looking in and then down
Term
What is the function of the inferior oblique? How is it tested?
Definition
Primarily extorsion, also causes elevation and abduction. Tested by looking in then up
Term
Movement of the eye must overcome what forces in the orbit?
Definition
Force to overcome viscous drag and maintain eccentric position
Term
What three pairs of cranial nerve nuclei contain neurons that innervate the extraocular muscles?
Definition
Oculomotor, trochlear, and abducens nucleus
Term
What connects the oculomotor, trochlear, and abducens cranial nerve nuclei?
Definition
Medial longitudinal fasciculus
Term
Step signals for tonic position are provided by what?
Definition
Nucleus prepositus hypoglossi and intestitial nucleus of Cajal
Term
The nucleus prepositus hypoglossi is responsible for what step signals?
Definition
Horizontal saccades
Term
The interstitial nucleus of Cajal is responsible for what step signals?
Definition
Vertical saccades
Term
What types of cells provide tonic inhibition of burst cells during fixation?
Definition
Omnipause cells
Term
What are the reflex response systems that compensate for movement of the head?
Definition
Vestibulo-ocular reflexes and the optokinetic system
Term
What provides input to vestibulo-ocular reflexes?
Definition
Driven by input from the vestibular apparatus and coordinated by the vestibular nuclei
Term
The optokinetic system compensates for what type of head movements?
Definition
Sustained or slow head movements
Term
The optokinetic system uses visual input to infer what?
Definition
Direction and speed of head movement, particularly whole field movement of visual scenes
Term
The optokinetic system activates what cells?
Definition
Wide-field retinal ganglion cells
Term
Wide-field retinal ganglion cells terminate in what nuclei?
Definition
Nucleus of the optic tract and accessory optic nucleus
Term
Signals from the wide-field retinal ganglion cells associated with the optokinetic system are relayed by the nucleus of the optic tract and accessory optic nucleus to what structures?
Definition
Vestibular nuclei and indirectly to vestibulocerebellum
Term
What is the effect produced by the optokinetic system?
Definition
Slow eye movements are produced to compensate for retinal slip to match direction and velocity followed by a rapid repositioning phase back to central position
Term
Rapid conjugate eye movement required for the acquisition of new visual targets is referred to as what?
Definition
Saccade
Term
What structure contains a retinotopic map of contralateral visual space used in directing eye movement?
Definition
Superior colliculus
Term
What tasks are performed by the superior colliculus?
Definition
Provides motor error coordinates, translates all relevant sensory information into motor error signals, projects to brainstem gaze centers and frontal cortex via thalamus
Term
What is the function of the cerebellar vermis in visual motor control?
Definition
Calibrates saccades, cerebellum is important for long term adaptation in eye movement control
Term
The frontal eye fields (BA 8) receive input from what?
Definition
Visual association cortex and thalamus regarding target location
Term
The frontal eye fields (BA8) project directly to what structures?
Definition
Brainstem gaze centers and the superior colliculus
Term
The frontal eye fields (BA8) are associated with what type of eye movements?
Definition
Volitional or memory guided saccades
Term
The parietal eye fields provide indirect influence related to what functions?
Definition
Visual selection/attention, provides a "salience map"
Term
What visual cortex provides information regarding target motion required for smooth pursuit in a shifting gaze?
Definition
Extrastriate visual cortex
Term
The extrastriate visual cortex relays information regarding target motion required for smooth pursuit in a shifting gaze to what structures?
Definition
Dorsolateral pontine nucleus via the frontal eye fields and the posterior parietal cortex
Term
What structure encodes direction and velocity of smooth pursuit after receiving visual input from the extrastriate visual cortex?
Definition
Dosolateral pontine nucleus
Term
What is required to maintain the fovea of each eye on a single target as its distance changes?
Definition
Vergence
Term
What structure is responsible for vergence and accomodation?
Definition
Supraoculomotor area of the midbrain
Term
What is an antisaccade task?
Definition
An inhibit reflexive saccade that shifts gaze in the opposite direction
Term
What might cause an antisaccade task?
Definition
Increased errors with frontal lobe dysfunction due to stroke and dementia
Term
Damage to what structure would impact the horizontal and vertical gaze centers?
Definition
Brainstem oculomotor system
Term
What part of the brain is crucial for smooth pursuit of eye movements?
Definition
Cerebellum
Term
Damage to the flocculus results in what type of smooth pursuit impairment?
Definition
Ipsilateral impairment and inability to hold eccentric eye positions
Term
What might cause saccade dysmetria?
Definition
Damage to the oculomotor vermis and fastigial nuclei
Supporting users have an ad free experience!