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