BIOLOGY 2C03 Lecture Notes - Extrastriate Cortex, Cerebellum, Vergence
28 Jan 2013
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Function: to redirect gaze from one point to another (change fovea target) Saccades are fast (peak velocity 500 /s, typical latency 200ms) and accurate. Target position info is first processed by the ppc and frontal cortex (especially the parietal and frontal eye fields) Both the pef and fef project to the superior colliculus (which has an ocular motor map) which then projects to the brainstem saccade generator. The brainstem saccade generator consists of (omnipause,) burst and integrator neurons (be able to describe how these function together to give saccadic pulse) The locations of the burst and integrator neurons differs for horizontal (pons) and vertical (midbrain) saccades. The cerebellum can modify saccades (from below, can predict lesion effects) Fastigial nucleus facilitates contraversive and inhibits ipsiversive saccades. Function: track moving objects (keeps target on fovea) Pursuit consists of 100ms latency, initiation (accel. of eye), and sustained tracking (gain=1) Pursuit can inhibit the vor reflex to allow head tracking as well.
