NROC64H3 Lecture Notes - Lecture 3: Extraocular Muscles, Oculomotor Nerve, Superior Rectus Muscle
Document Summary
Allows us to focus the fovea (best visual acuity in fovea) of the reti(cid:374)a to a regio(cid:374) of (cid:858)i(cid:374)terest(cid:859) For example: vergence eye movements two eyes move to point the fovea at an object in a different depth plane. Metabolic cost of frequent and fast movements are low. Maximizing the number of locations that benefit from fixating. Eyes move in a conjunctive way: the movements in each eye have the same amplitude and direction. Conjugate movements: each eye moves the same amount in the same direction: ex. Disconjugate movements: eyes move in slightly different directions and sometimes by different amounts: ex. For the eyeball to make a saccade it must overcome forces imposed by orbital supporting tissue: accomplishes this by contracting the extraocular muscles. Requires the phasic activation of neural activity in the eye movement control system to overcome gravity, viscous drag and elastic forces: requires tonic activation of the extraocular muscles to keep the eye in the new position.
