Finally, the moment that no one has been waiting for. Some neuropsychological aspects of insight and misattribution. I'm strictly an amateur, but I love this stuff.
For all my political wonks who stop by, I am not going to expand this into wild speculations about how liberals must have decreased volume in *Brodmann Areas 9/10 and 40 /41. I think relays through the parietal areas are the more likely culprits for that sort of lack of insight, same as for conservatives, libertarians, greens, and communitarians. That (or second choice, temporal regions) is where previous info and emotional content interfere with the relay of signals from one part of the brain to another.
Okay, not communitarians. They really might have some subtle neurological deficits.
The articles: Specific Frontal Lobe Subregions Blah Blah Blah, Journal of Neuropsychiatry May 2001, by Flashman, McAllister, et al. I started with this one because I know Flashman, who is cute as a button, and MCAllister, who does a great Mick Jagger impression after a few drinks. They led me on to the other articles. I don’t know anything about those authors, but I’ll bet they’re equally eccentric. Neuropsych people are about the most interesting folks to hang out with.
Insight and regional brain volumes, etc. European Archives of Clinical Neuroscience, September 2006, by Bassitt, et al.
Unawareness of illness yada yada yada Psychiatry Research: Neuroimaging, November 2000, Laroi, Fannemel, and a bunch of other Norwegians.
I am not going to footnote any better than that. Less than five of you are going to be looking this up anyway.
There is lots of evidence that lack of symptom awareness in schizophrenics is associated with frontal-executive functioning. People who misattribute symptoms or don’t recognize their symptoms often score poorly on the Wisconsin Card Sort (as one example), which is known to have heavy frontal lobe involvement in its performance. Awareness of symptoms seems to be independent of general psychopathology; that is, sicker patients are neither more nor less likely to be aware of their symptoms that those with milder symptoms. Lack of insight and awareness may correlate more with undifferentiated than paranoid schizophrenia, giving further evidence that these are two separate illnesses, with separate brain changes.
Lack of insight doesn’t seem to correlate with age, education, age of onset, duration, or number of admissions. You’d think it might, but the actual correlations are all brain stuff.
But finding actual brain changes had been elusive. There were some hazy suggestions that lack of insight was related to decreased frontal lobe volume, but nothing robust; nothing sexy and eureka worthy. Recently there have been some tantalizing suggestions of what specific regions of the frontal lobes are affected. These are volumetric studies, and fMRI studies are apparently underway at Dartmouth and elsewhere.
All three studies suggest that the dorsolateral prefrontal cortex is specifically involved in lack of insight. The DLPFC and the cingulate gyrus are important parts of working memory, and the decreased volume in those areas suggests that working memory is strongly related to insight and awareness. (For brain fanatics only: Specifically, unawareness was inversely correlated with bilateral middle frontal gyrus, right gyrus rectus, and left anterior cingulated gyrus volumes). A possible explanation of this would be that working memory is necessary for a person to compare current situations to previous ones. Without this baseline, the brain makes up its interpretations new every day, based on the (faulty) information it is receiving. Old information, while retrievable, is not held effectively in the brain. If you have ever “filed something away temporarily” in your brain for immediate retrieval while you are doing something else, you can see why an inability to do this would hamper your ability to interpret events around you.
Misattribution of symptoms was correlated more exactly with smaller volumes of the superior frontal gyrus. That is, people who saw outside agents as the cause of their symptoms were more likely to have diminished gyri. You don’t need to memorize any of this except to note that misattribution and unawareness correlated with different brain areas. For the people really into this stuff, I will note that there were less robust but significantly reduced volumes at the temporal neocortex, insula, and precentral gyri.
What’s it all mean? Lack of insight and misattribution are separate symptoms in schizophrenics. Traditional antipsychotics are not known to much affect the brain areas affected. The new atypicals may affect these areas subtly, but these are two symptoms we are not presently denting very much. We don’t know if similar brain areas are affected in people with other illnesses who lack insight, but it is possible, because people who have brain injuries to those areas show similar symptoms.
*Brodmann Areas are an older brain map that don’t isolate brain functions as well as we can do now with more sophisticated measurements, but have the advantage of everyone knowing where in the brain you’re talking about.