Richard Gordon gordonr at cc.UManitoba.CA
Thu Mar 30 06:41:04 EST 1995

Dear Pejman:
I would appreciate hearing what refs you get. I myself have written the=20
following, and would appreciate your comments, and those of others on=20
this list.
Best regards, -Dick Gordon, U.Manitoba[Mar30,95]

Extract from: Gordon, R. (1995). The Hierarchical Genome and=20
Differentiation Waves: Novel Unification of Development, Genetics, and=20
Evolution (Singapore: World Scientific), in prep.

We can also begin to speculate on whether specific, perhaps congenital=20
mental anomalies, such as dyslexia (J. Hinshelwood in {Benton & Pearl,=20
1978}), autism ({Courchesne, Press & Yeung-Courchesne, 1993; Courchesne=20
et=CAal., 1994; Courchesne, Townsend & Saitoh, 1994}), and schizophrenia=20
({Gershon & Rieder, 1992}), or localized effects of teratogens ({Yasuda=20
et=CAal., 1989}) or domestication ({Kruska, 1988}), are due to incomplete=
unfolding of the brain's portion of the differentiation tree via=20
differentiation wave defects, or insufficient or excessive trajectories=20
of differentiation waves. Programmed cell death, presently called=20
"apoptosis" ({Alison & Sarraf, 1992; van=CAder=CAHoeven et=CAal., 1994}), i=
now regarded as a terminal step of differentiation ({Tomei &=CACope,=20
1994}). On the positive side, it will be interesting to determine to what=
extent the evolution of the brain is a function of changing allometry=20
({Deacon, 1988}) versus elaboration of the differentiation tree.

In schizophrenia, in prefrontal cortex, less apoptosis occurs (cf. {Crow,=
1984; Woody et=CAal., 1987; Goldman-Rakic, 1992; Bookstein, 1995})}), which=
further suggests that schizophrenia may be caused by incomplete playing=20
out of the differentiation tree (Murray B. Stein, personal communication):

"A large body of research literature has demonstrated that schizophrenia=20
is very much a physical illness.... more than 50 studies have=20
demonstrated that patients with schizophrenia may have abnormalities in=20
structure... on CT [computed tomography] scans.... The presence of these=20
abnormalities suggests that nerve tissue either has been lost or has=20
failed to grow normally; the bulk of the current evidence suggests that=20
the abnormality may be neurodevelopmental..., because... the disease=20
process in the antedates the onset of symptoms.... Since both [of=20
identical] twins have schizophrenia approximately 40 percent of the time,=
we learn that schizophrenia has an important genetic component; since 60=20
percent of identical twins do not share schizophrenia, however, we also=20
learn that genetics alone cannot explain the cause of schizophrenia....=20
Various factors that could serve as environmental causes include viral=20
infections, toxins, and birth injuries" ({Backlar, 1994}).

"There are indications that something  is going on in the developing of=20
some people who later develop schizophrenia, but no one factor appears to=
be clearly associated. The pathology observed on the MRIs [magnetic=20
resonance images] includes some dilatation of the cerebral ventricles, as=
well as some loss of volume of the hippocampus - amygdala complex. Both=20
of these changes are nonspecific and, at least the latter, most likely=20
take place during early stages of development.... The developmental=20
theory postulates that any one of a number of etiological agents could=20
initiate the causative cascade leading to schizophrenia if  that agent=20
affected the at a crucial stage of development" (A.D. D'Velupmoni in=20
{Torrey et=CAal., 1994}).

Suggestons of "faulty wiring" in psychopathy ({Hare, 1993}), including=20
reduced brain lateralization ({Hare & McPherson, 1984; Hare &=CAJuta, 1988;=
Raine et=CAal., 1990}), may warrant being looked at from the point of view=
of uncompleted differentiation trees for the brain.

refs on request

More information about the Neur-sci mailing list