smooth pursuit and vergence eye movements

Question 1

name the 2 purposes of the supra nuclear higher centres

Answer 1

• initiate eye movements (inc two different types of voluntary) for different purposes and improve their coordination and accuracy
• send motor commands to the particular brainstem generator

Question 2

what is the purpose of the brainstem generator nuclei

Answer 2

generate specific burst patterns of activity and deliver these ocular motor neurons via axons in the inter-nuclear pathways (MLF)

different brainstem generators for slow conjugate smooth pursuit and for dysjunctive/versions and vergence via various pathways

Question 3

list the 5 higher control centres for slow eye movements

Answer 3

• 1) parietal eye field PEF and area 2) MST, V5/MT: have different aspects of motion processing and send outputs to the parietal eye field in the superior parietal cortex
• 3) midline cerebellar cortex and 4) nuclei: where motor commands go to, nuclei are deep i.e. the fastigule and interpose nuclei
• 5) midbrain accessory optic nuclei: largest nucleus of optic tract, for smooth pursuit only and has no contribution to vergences

Question 4

what is motion perception and smooth pursuit eye movements for

Answer 4

for tracking moving objects

Question 5

describe a smooth pursuit/tracking eye movement

Answer 5

• conjugate (both eyes move in same direction)