Oliver Sacks: What hallucination reveals about our mind (TED talks)
Oliver Sacks talks about how it is not only our eyes that “see” but also our brains. He talks about a completely blind patient, who for a few days had been “seeing things”. He diagnoses this woman with Charles Bonnet syndrome - specific types of visual hallucinations that affect the visually impaired. He also describes how hearing impaired individuals sometimes get auditory hallucinations, and the visually impaired sometimes get visual hallucinations.
He makes the distinction between these visual hallucinations and psychotic hallucinations - the former never address the individual experiencing them - they are somewhat like a silent movie sometimes - whereas the latter always address the individual.
In the video he talks about the brain areas that are associated with the different hallucinations, which have been found thanks to fMRI.