Inactivating V1 with TMS could induce some degree of akinetopsia 60–70 ms after the onset of the visual stimulus. TMS of V1 is not nearly as effective in inducing akinetopsia as TMS of V5. Alzheimers disease
Besides memory problems, Alzheimers patients may have varying degrees of akinetopsia. This could contribute to their marked disorientation. While Pelak and Hoyt have recorded an Alzheimers case study, there has not been much research done on the subject yet. Antidepressants
Inconspicuous akinetopsia can be triggered by high doses of certain antidepressants with vision returning to normal once the dosage is reduced. Areas of visual perception
Two relevant visual areas for motion processing are V5 and V1. These areas are separated by their function in vision. A functional area is a set of neurons with common selectivity and stimulation of this area, specifically behavioral influences. There have been over 30 specialized processing areas found in the visual cortex. V5
V5, also known as visual area MT (middle temporal), is located laterally and ventrally in the temporal lobe, near the intersection of the ascending limb of the inferior temporal sulcus and the lateral occipital sulcus. All of the neurons in V5 are motion selective, and most are directionally selective. Evidence of functional specialization of V5 was first found in primates. Patients with akinetopsia tend to have unilateral or bi-lateral damage to the V5. V1
V1, also known as the primary visual cortex, is located in Brodmann area 17.
V1 is known for its pre-processing capabilities of visual information; however, it is no longer considered the only perceptually effective gateway to the cortex. Motion information can reach V5 without passing through V1 and a return input from V5 to V1 is not required for seeing simple visual motion. Motion-related signals arrive at V1 (60–70 ms) and V5 (< 30 ms) at different times, with V5 acting independently of V1. Patients with blindsight have damage to V1, but because V5 is intact, they can still sense motion. Inactivating V1 limits motion vision, but does not stop it completely. Ventral and dorsal streams
Another thought on visual brain organization is the theory of streams for spatial vision, the ventral stream for perception and the dorsal stream for action. Since LM has impairment in both perception and action (such as grasping and catching actions), it has been suggested that V5 provides input to both perception and action processing streams. Case studies
Potzl and Redlichs patient
In 1911, Potzl and Redlich reported a 58-year-old female patient with bilateral damage to her posterior brain. She described motion as if the object remained stationary but appeared at different successive positions. Additionally, she also lost a significant amount of her visual field and had anomic aphasia. Goldstein and Gelbs patient
In 1918, Goldstein and Gelb reported a 24-year-old male who suffered a gunshot wound in the posterior brain. The patient reported no impression of movement. He could state the new position of the object (left, right, up, down), but saw "nothing in between".