Hirsch - Eye Movements Flashcards
acuity falls off with
eccentricity in visual space
calcified amygdala
focus on nose area where emotion is less expressed; has hard time knowing facial expression. When directed, performance increases
eye musces
superior rectus
medial rectus
lateral rectus
inferior rectus
superior oblique
inferior oblique
eye muscles responsible for horizontal movement
lateral rectus - abdution away from the nose
medial rectus - adduction towards the nose
eye muscles responsible for vertical movement
superior rectus - elevation
inferior rectus - depression
eye muscles responsible for torsional move
ents
superior oblique - intorsion
inferior oblique - extorsion
innervation of the extraocular muscles
- oculomotor nucleus-Midbrain -via Cranial nerve III (ipsilaterally)–> inferior rectus, inferior oblique, medial rectus, superior rectus
- abducens nucleus-Pons -via Cranial nerve VI (ipsilateral) –> lateral rectus
- Trochlear nucleus-Caudal midbrain - via Cranial nerve IV (contralateral) –> superior oblique
Types of eye movements
1. direct gaze to target of interest OR track targets as they move
—> saccades, smooth pursuit, optokinetic nystagmus
Types of eye movements
2. Help align fovea of each eye on the target of interest * when distances between each eye and target are different
–> disconjugate vs. conjugate movement; eyes moving in different directions; vergence movement
Types of eye movements
3. movement that compensate for head movement to keep the target of interest centered on the fovea
vestibulo-ocular movements
saccade cannot stop once started
very fast
neural firing during movement and at rest
when moving; intense fire
when stretched less intense yet steady fire
moving eye to the right
Right Paramedian Pontine Reticular Formation (PPRF) => right abducens nucleus =====>
- => abducens or 6th nerve (excitatory; contracts) => right lateral rectus (ipsilateral)
- => medial longitudinal fasciculus (axon of internuclear neurons) => left oculomotor nucleus (contralateral) => oculomotor or 3rd nerve => left medial rectus
know picture in 13/19
pineal gland superior colliculus inferior colliculus trochlear nerve fourth ventricle pulvinar of thalamus superior cerebellar peduncle
visual and motor maps in superior colliculus
cartesian map of visual space in the colliculus
dorsal midbrain OR PARINAUD syndrome
- caused by a tumor of the pineal gland or multiple sclerosis or vascular lesions
- compresses the superior colliculi
- paralysis of UPWARD gaze
- not clear if ONLY superior colliculi involved
== center for vertical eye movements (rostral interstitial nucleus) lies just rostral to the superior colliculli and could be involved
cortical control of eye movements
primary motor cortex
frontal eye field (parietal cortex) -> superior colliculus (midbrain) -> PPRF - horizontal gaze center (pons)
Damage to only Superior colliculus
impede ability to make rapid saccades
*short - but not long term - loss in ability to make saccades
Damage to pnly Frontal Eye Fields
impairs ability to make voluntary movements away from a salient stimulus OR towards remembered positions
*short - but not long term - loss in ability to make saccades
Damage to both Superior colliculus and frontal eye fields
permanent loss of ability to make saccade
Frontal eye fields
attentional regulation of neural activity
attention==> hard fire
