Cerebral akinetopsia

From Psy3241

Cerebral akinetopsia is a syndrome in which a person loses the ability to perceive visual motion due to damage in the visual cortex. A patient with akinetopsia may suffer from defective smooth pursuit eye movements, reaching for moving objects, and the identification of objects that are defined by movement cues. Akinetopsia is caused by lesions to the middle temporal area (MT) also known as V5.


Akinetopsia Video


L. M.

In the most famous case of akinetopsia, patient L. M. showed severe deficits in her visual processing of movement due to damage to bilateral damage in the posterior section of her cortex. L. M. ability to see moving objects was affected by the speed at which the objects were moving. Targets moving horizontally or vertically at or less than 10 to 14 degrees per second were visible. However, if objects moved faster than this, she reported them as being located at successive points instead of continuous movement.

hemi-akinetopsia

Hemi-akinetopsia is when a patient suffers from akinetopsia in only one half of their visual field. This usually due to a stroke that affects the MT in either the left or right hemisphere.


ref: Motion and shape perception in cerbral akinetopsia, Rizzo et al., Brain (1995), 118, pg. 1105-1127.

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