Hirsch - Eye Movements Flashcards Preview

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Flashcards in Hirsch - Eye Movements Deck (21):
1

acuity falls off with

eccentricity in visual space

2

calcified amygdala

focus on nose area where emotion is less expressed; has hard time knowing facial expression. When directed, performance increases

3

eye musces

superior rectus
medial rectus
lateral rectus
inferior rectus

superior oblique
inferior oblique

4

eye muscles responsible for horizontal movement

lateral rectus - abdution away from the nose
medial rectus - adduction towards the nose

5

eye muscles responsible for vertical movement

superior rectus - elevation
inferior rectus - depression

6

eye muscles responsible for torsional move
ents

superior oblique - intorsion
inferior oblique - extorsion

7

innervation of the extraocular muscles

1. oculomotor nucleus-Midbrain -via Cranial nerve III (ipsilaterally)--> inferior rectus, inferior oblique, medial rectus, superior rectus
2. abducens nucleus-Pons -via Cranial nerve VI (ipsilateral) --> lateral rectus
3. Trochlear nucleus-Caudal midbrain - via Cranial nerve IV (contralateral) --> superior oblique

8

Types of eye movements
1. direct gaze to target of interest OR track targets as they move

---> saccades, smooth pursuit, optokinetic nystagmus

9

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

10

Types of eye movements
3. movement that compensate for head movement to keep the target of interest centered on the fovea

vestibulo-ocular movements

11

saccade cannot stop once started

very fast

12

neural firing during movement and at rest

when moving; intense fire
when stretched less intense yet steady fire

13

moving eye to the right

Right Paramedian Pontine Reticular Formation (PPRF) => right abducens nucleus =====>
1. => abducens or 6th nerve (excitatory; contracts) => right lateral rectus (ipsilateral)
2. => medial longitudinal fasciculus (axon of internuclear neurons) => left oculomotor nucleus (contralateral) => oculomotor or 3rd nerve => left medial rectus

14

know picture in 13/19

pineal gland
superior colliculus
inferior colliculus
trochlear nerve
fourth ventricle
pulvinar of thalamus
superior cerebellar peduncle

15

visual and motor maps in superior colliculus

cartesian map of visual space in the colliculus

16

dorsal midbrain OR PARINAUD syndrome

1. caused by a tumor of the pineal gland or multiple sclerosis or vascular lesions
2. compresses the superior colliculi
3. 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

17

cortical control of eye movements

primary motor cortex
frontal eye field (parietal cortex) -> superior colliculus (midbrain) -> PPRF - horizontal gaze center (pons)

18

Damage to only Superior colliculus

impede ability to make rapid saccades
*short - but not long term - loss in ability to make saccades

19

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

20

Damage to both Superior colliculus and frontal eye fields

permanent loss of ability to make saccade

21

Frontal eye fields

attentional regulation of neural activity
attention==> hard fire