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Schizophrenia in Split-Brain Individuals

F. Frank LeFever flefever at ix.netcom.com
Fri Mar 26 03:08:47 EST 1999


(1) This is a very simplistic notion of "schizophrenia".  Given the
very wide range of symptoms and the wide range of brain regions
implicated, to take one (not universal) symptom and call it the "cause"
of schizophrenia is rather perverse.

(2) My impression is that metabolic imaging studies or other procedures
for localizing activation during hallucinations implicate left
hemisphere activity (possibly overactivity??); perhaps Jaynes' model
allows this, but would require evidence of right hemisphere activity
"leading" this (i.e. in time). 

(3) Does he think of the right hemisphere "goading" the left hemisphere
into covert speech, or does he imagine right hemisphere SPEECH being
picked up by or "dictated to" the dleft hemisphere?  If the latter, it
suggests he gives the right hemisphere credit for greater language
ability than is usualy accorded it.

(4) Given the rather small number of split-brain cases, base rates of
schizophrenia might be too small for incidence of schizophrenia to be
evaluated.  Of course, ONE case of a split-brain patient with
auditory/verbal hallucinations would suffice to disprove his
conjecture!

(5) A more likely explanation would be based on known frontal lobe
abnormalities in schizophrenia, making self-control and self-monitoring
problematic.   It occurs to me just now (belatedly, since I have
published some work on this) that the role of the prefrontal cortex in
"source memory" might be relevant here (i.e. some frontal lesions can
impair awareness of where/when/how one saw or heard something although
memory of the event is ottherwise intact).

(6) I hope you won't mind my crossposting this to bionet.neuroscience;
some really sharp neuroscientists read that newsgroup and one of them
MIGHT have special knowledge of split-brain cases.

F. Frank LeFever, Ph.D.
New York Neuropsychology Group

In <SPR990325160138-15257 at kauri.vuw.ac.nz> "Nathan Chronister"
<evolution at catskill.net> writes: 
>
>In 1976, Julian Jaynes hypothesized that schizophrenia is the result
of
>right hemisphere brain activity generating hallucinated speech in the
left
>hemisphere.  If this hypothesis is correct, schizophrenia should not
occur
>in split-brain individuals (those lacking the corpus callosum and
anterior
>commisures).  Jaynes didn't mention whether this was the case, and I
suspect
>he didn't have any data on schizophrenia occuring or not in
split-brain
>patients.  So my question is, does anyone know of any examples of
>schizophrenia in a split-brain person, or any studies of schizophrenia
in
>split-brain subjects?
>
>Sincerely,
>Nathan Chronister

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