Term
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Definition
| we do not ordinarily perceive the worls as moving when we move our eyes |
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Term
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Definition
| info from proprioceptors in the eye muscles tell the brain that the eye moved, leading to visual stability and direction constancy |
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Term
| Evidence for inflow theory |
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Definition
| Steinback has shown that stretch receptors exist in the tendonous insertions of the eye muscles. |
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Term
| Evidence against inflow theory |
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Definition
1) push eye with finger, activate stretch receptors as well as move eye but we do not perceive the world as stable
2) motion is seen by patients who have paralyzed eye muscles.
3) von holst experiement and brindley's experiment |
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Term
Von Holst Experiment
(patient's eye muscles are paralyzed) |
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Definition
1) told patient to move eye to the right, and patient was able to perceive the visual world moving to the right
2) von holst moved the patient's eye manually to the right (retinal displacement) and patient reported seeing visual world moved to the left
3) von holst now moved eye mechanically to the right while telling patient to move their eye to the right, patient perceived visual world as stationary. |
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Term
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Definition
| Eyes were anesthetized at surface but muscles attached to eye could provide feedback to the brain about movements of the eye. patients could not tell that the eyes were being moved mechanically. |
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Term
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Definition
| efferent info from eye movement control nuclei are compared with sensory info thereby leading to visual stability and direction constancy. |
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Term
| Evidence for Outflow Theory |
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Definition
1) explains failure of inflow theory
2) explains phenomenon of past pointing
3) electrophysiological evidence - cells in superior colliculus that have properties suggested by outflow theory
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Term
Vection
(visually induced motion of self) |
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Definition
1) subtypes: circular and linear vection
2) visually induced sensations of body motion are indistinguishable from sensations coming from actual motions of the body
3) involves the vestibular system
4) self motion result from either vestibular or visual input and id they are discrepant you get motion sickness. |
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Term
| Sensory Re-arrangement Theory |
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Definition
| motion sickness due to discrepancies in sensory input |
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Term
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Definition
| strong kind of motion sickness produced when person is spun around vertical axis with their head tilted. |
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Term
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Definition
| motion sickness produced when visual stimuli are rotated around the observer who has their head tilted. |
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Term
| Why does reading in a car cause motion sickness? |
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Definition
Vision says there is not motion but our vestibular system says there is.
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Term
| How to suppress motion sickness? |
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Definition
optimize the agreement between the two senses to minimize magnitude of the motion sickness.
Ex: look at horizon while on a ship, or look out front window of a car. |
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