Question

Blindsight is a paradoxical phenomenon where people with damage to the primary visual cortex can respond to visual stimuli without being consciously aware of them. What do you make of these separate "unconscious" vision pathways? What do they tell us about the visual system?

Answer 1

Blindsight is the phenomenon in which the people who are cortically blind will be able to respond to some of the stimuli of the visual cortex, though not in a conscious manner. These patients will be having conscious blindness on one of potion of their vision. This is observed as there would be destruction of the striate cortex,

As a result of blindsight, it could be demonstrated that even though the more complex form of visual system would be damaged in the individuals, they would be able to use their latter visual system for guiding hand movements as well as reaching for objects. This implies, that the visual system would be able to produce a visual format even without having a conscious sensation. This implies that the ability of unconscious stimuli forms a part of the brain and that only some parts of the brain would be able to play a role in consciousness.

There is presence of awareness of the visual features, though, there might not be a holistic visual perception. This implies that even in the individuals who are sighted, there would be presence of a blinding process, that would be completing the entire process of perception.

The mediation of blindsight has been attributed to the presence of a primary visual cortex that would be extending towards the superior colliculus from the eye. On the other hand, some of the theories suggest the presence of separate cortex islands that would be present in the lesion. This suggests that blindsight is a form of reduction if the normal vision and its sensitivity.

Also, in some of the theories it has been suggested that the residual vision takes place as a result of pathways that are extending out of the primary visual cortex. This imokus that the retina would be projecting to other sites in the thalamus, or in the midbra H as well as the hypothalamus. These would be sending projections to the cerebral cortex resulting in blindsight.