Quiz 3 - Starts at Topic 3 slide 24 Eye movements 1 There...

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Starts at Topic 3 slide 24 Eye movements 1. There are 5 types of eye movements: 1. Saccades 1. Very fast 2. Bring new images of interest onto fovea 1. Extract information about that visual object 2. Blind people can produce saccades/eyes closed—don’t need image to produce saccades 3. REM sleep—Rapid eye movement 1. When you see people’s eyes move while sleeping 4. Rapid movements of the eyes. 5. Infrared corneal reflection 1. Used for marketing and advertising—to see where people look first. Make that image bigger and spend more time on that location. 2. Smooth Pursuit 1. Track moving objects 2. Maintain image on fovea 3. IMAGE NECESSARY! 1. Difference between saccades 1. Saccades are jumping movements 2. When your eyes are following a baseball, your eyes are matching the velocity of it. 3. 200 ms after movements starts to move, your eyes are in saccades, then smooth pursuit 4. You will continue to produce smooth pursuit for 50 ms after image is gone, then produce saccades again—attend to regions ahead of it (when it disappears) 3. Vergence 1. Oppositional movements of the eyes 2. Breakdown vergence into convergent and divergent 1. Convergent—eyes move towards each other: adducting 1. Ex. When a bug flies towards nose, eyes will adduct 2. Divergent—contract both lateral, abduct away from each other 1. Ex. When bug fly away and watch it fly away, eyes will abduct 3. Use eye movements to eliminate retina disparity 1. Retinal disparity—results when image of one object lands on non corresponding parts of each retina, you perceive two. 2. Results in diplopia 1. Ex. Take two fingers put in front of nose. See 2 pages of further finger 4. Vestibulocular reflex (VOR ) 1. eye movement that allows you to maintain stable gaze at one position in space while your head/body is moving around. 5. Optokinetic nystagmus (OKM) 1. Being a passenger in a car. Car is traveling high speed. Pick out an object far away, focus it. Use smooth pursuit to track it then saccade to look forward. Then smooth pursuit 1. Shaking of the eye 2. Nystagmus—eyes will start to shake when looking far left/right (alcohol’s effect) police tests 2. Neural control of eye movements 1. Eye movements controlled in the brainstem: superior colliculus 1
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1. Superior colliculus affected by several cortical and subcortical sites 1. From V1 dorsal stream frontal and supplementary superior colliculus 2. Frontal and supplementary eye fields– used to form a plan (want to look somewhere). That plan is based on information coming in from parietal lobe 1. Frontal and supplementary collect message. 2. Dorsal and ventral streams, important to have parietal so you know where it is. Where in respect to yourself
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Quiz 3 - Starts at Topic 3 slide 24 Eye movements 1 There...

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