Reality monitoring and psychosis

csp_wormlight.jpgMixing Memory has a fantastic account of recent research on memory distortions in schizophrenia that might explain the unusual experiences and strange ideas that characterise the condition.

Memory distortions are often tested by the use of ‘source monitoring’ or ‘reality monitoring’ experiments (largely invented by Marcia Johnson), where participants are given a list of words and asked to read some of the words out loud, and imagine themselves reading the others out loud.

Afterwards, participants are given a recognition test where they are shown each word and asked whether they read it out, or imagined reading it out.

There are many variations on this theme, but a consistent finding is that those with symptoms of psychosis are more likely to confuse words they imagined reading out with those they said out loud.

The Mixing Memory article tackles a recent study which ran a similar experiment while brain-scanning participants to see which areas would be active when distortions were present.

It turns out that less activity in an area of the frontal lobe called the the medial anterior pre-frontal cortex was linked to more memory distortion errors.

One difficulty though, is that this form of memory distortion is also present in people who have no signs of mental illness but have some delusion-like ideas or experience sensory distortions, suggesting that this effect cannot explain psychosis completely.

Link to ‘Was it Real or Did I Imagine It? Source Monitoring, Schizophrenia, and Our Grip On Reality’

One Comment

  1. Kschltr
    Posted June 28, 2006 at 8:30 pm | Permalink

    I’m sure yer not suggesting that this a new theory as relates to memory processing through the pre-frontal cortex and/or anterior frontal lobe?
    That was why they used to do LOBOTOMIES. To disconnect that part of the archetecture which was not specifically conditioned for analytical/objective data processing and instead tended to contribute to or mediate untoward emotional responses. Persons who had their pre-frontal lobe connections severed surgically tended to be flat emotionless and EASIER TO CONTROL. At least temporarilly, until the phenomenon known as NEUROPLASTICITY kicked in and new connections were made or other regions modified themselves to produce the necessary emotional response (appropriately or inappropriately as the case may have been).
    Folks who are BRAIN INJURED develop a remarkable capacity for adaptation and since we only use 10 – 20 percent of our neurological capacity in general at any time, as is currently measureable, many brain injured or seemingly comatose patients may infact have developed the ability to maintain some semblance of internal homeostasis, while others very likely do not.
    This argument does nothing to advance neurological science, but begs the question; “Do comatose or vegatative patients have the ability to integrate neuroplasticity and the brain’s natural tendency towards confabulation and dream state creations, into a delusional reality which is, for them, survivable and even pleasant in some cases? Who get’s to do the research, and who get’s to decide? Who knows and who helps. I have had comatose patients spontaneously recover after being comatose for a couple of weeks because I talked to them as if they were in the room while I tended to their needs as an orderly or later as a nurse.
    I’ve also had two head trauma patients in a room side by side, both had taken headers off of their motorcycles without helmets, and had a neurosurgeon tell me; “The guy on the left will recover most of his functions, but the guy on the right will be like this for the rest of his life..”
    When I asked him what the difference was he said; “Similar injuries by the physical location of the damage in one patient was about a 1/2″ away from a critical area of the brain and the other patient has severe damage to that area.
    Still doesn’t answer the question though, does it?


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