Oculomotor Terms

Question 1

Accommodation

Answer 1

adjustment of the lens and pupil shapes in order to focus on object

Question 2

Convergence

Answer 2

both eyes moving medially to focus on an object as it moves closer to the eyes (near point).
via the bilateral medial rectus muscles and bilateral CN3

Question 3

Divergence

Answer 3

both eyes moving laterally to focus on an object as it moves farther from the eyes (far point).
via lateral rectus muscles and bilateral CN6

Question 4

Conjugate

Answer 4

eye movements as you track an object into different quadrants of the visual field: left, right, up, down, etc.

Question 5

Saccades

Answer 5

quick shift of the eyes from one object to another. Coordinated by the Superior Colliculus.

Question 6

Smooth Pursuit

Answer 6

slow tracking of an object as it moves across the visual field. Coordinated by the vestibular nuclei.

Question 7

Nystagmus

Answer 7

involuntary, repeated saccades, which are an attempt of the nervous system to stay focused on an object. Involves a slow phase and a fast phase.

Question 8

Optokinetic

Answer 8

This reflex occurs to allow smooth pursuits. It is synonymous with the slow phase of nystagmus.

Question 9

Oculomotor nuclei

Answer 9

This cranial nuclei has lower motor neurons which control all but 2 extra-ocular muscles.

Question 10

Trochlear nuclei

Answer 10

This cranial nuclei of the midbrain contains lower motor neurons which control the Superior Oblique Muscle, which assists with downward and inward movement of the eye.

Question 11

Abducens

Answer 11

This cranial nuclei of the pons contains lower motor neurons which control the lateral rectus muscle, which produces lateral movement of the eye toward the temple.

Question 12

Upward

Answer 12

This direction of eye movement requires cranial nuclei 3 of both eyes.

Question 13

Downward

Answer 13

This direction of eye movement requires cranial nuclei 3 and 4 of both eyes

Question 14

Left

Answer 14

Moving both eyes to gaze into this visual field requires cranial nerve 6 of the left eye, and cranial nerve 3 of the right eye

Question 15

Midbrain

Answer 15

location of the vertical gaze centers, which coordinate the firing of cranial nerves 3 and 4.

Question 16

Pons

Answer 16

location of the horizontal gaze centers, which coordinate the firing of cranial nerves 3 and the contralateral cranial nerve 6.

Question 17

Medial Longitudinal Fasciculus

Answer 17

bundle of axons in the midline of the pons and midbrain. responsible for coordinating eye movements of both eyes simultaneously.

Question 18

Superior Colliculus

Answer 18

responsible for coordinating saccadic movements of the eyes, either reflexively from the Retinal Ganglion Cells, or volitionally via the Cortical Eye Fields

Question 19

Vestibular Nuclei

Answer 19

coordinate the smooth pursuits tracking of an object as it moves

Question 20

DLPFC

Answer 20

part of the cerebral cortex which is essential for voluntarily suppressing (Inhibiting) saccades of the eyes

Question 21

Frontal Eye Fields

Answer 21

part of the premotor cortex, plan voluntary eye movements, whether saccades or smooth pursuits

Question 22

Parietal Association

Answer 22

area of the cerebral cortex integrates visual, vestibular, and somatosensory inputs.

Question 23

Vestibulocerebellum

Answer 23

responsible for coordinating and fine-tuning the movements which are initiated by vestibular nuclei

Question 24

Basal Ganglia

Answer 24

initiation and suppression of movement. Eye movements resulting from this loop are Volitionally-driven via input from the Frontal Eye Fields.