This week's edition of the excellent All In The Mind radio show is about auditory hallucinations, specifically "hearing voices." From the transcript of the program:
(Monash University psychiatry professor) David Copolov: We think of voices maybe as a distortion of auditory memories, we have memories of things that we've heard and things that have been said to us and it's our current conceptualisation that these voices are replayed, but in a very real sense of auditory memories and a distortion of these auditory memories feeding in to the regions of the brain that process hearing.
(show host) Lynne Malcolm: So could you tell me a little bit more about what we know about what happens in the brain with auditory hallucinations?
David Copolov: Well a series of studies by our group and others has shown that during hallucinations there are regions of the brain that become active. And those regions commonly involve the regions of the brain, the temporal lobe under the temple that are associated with the processing of normal sounds. So it's as if the brain is being tricked, or the person is being tricked into believing that these voices are actually occurring because there's spontaneous activation of these hearing regions of the brain. There is also activation of regions of the brain, especially the hippocampu,s that are associated with the processing of memory, which is why we believe it's a combination of reactivation of memories with the false perception of external or internal voices.
Have you heard of phantom limb syndrome, where a person who might have had an amputation can feel their arm or leg even though the leg has been amputated? It's the part of the brain that is deprived of input from that region of the body, the brain responds to a lack of input by activity. So in hallucinations, auditory hallucinations, even though we've shown that there are subtle abnormalities of the hearing brain but not deafness as such, the evidence is that those base line abnormalities actually give rise to spontaneous eruptions within the dysfunctional hearing brain that then gives rise to this experience of hearing voices.
Link (via Mind Hacks)
