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The Amygdala and Human Evolution.. A connection????

NMF neil.fournier at sympatico.ca
Mon Jan 26 15:51:16 EST 2004

Although the actual link between sex and the amygdala was advocated even
before Heinrich Kluver and Paul Bucy work in the thirties and forties.  (.
However, in order to provide an historical note to K.P. Collins previous
post, the initial interest with the mesial temporal lobe and the amygdala
came from Kluver's interest on the effects of mescaline on perception,
particularly on himself.  His fascination can be seen in his book called
Mescal, the Divine Plant (an interesting read by the way).  He was
interested in mescaline because the hallucinations or auras preceding many
temporal lobe ("limbic") seizures resembled the type of experiences commonly
reported during mescaline-induced hallucination.  Thus, his experiments
initially looked at how removal of the temporal lobe (by Bucy) would alter
the effects of mescaline-induced hallucinations following the resective
surgery.    He found no difference between the non-surgical and surgical
conditions with respect to mescaline-induced hallucinations.

The most obvious changes that excited researchers besides the hypersexual
behavior was the accompanied "psychic blindness" or visual agnosia.  This
research led way to the later  suggestion that the inferior temporal cortex
may be an important part of the circuit mediating aspects of visual
perception.  (However, if people actually read the literature, they would
have long realized that this supposed recent idea was already experimentally
verified in the earlier works of Brown and Schafer that date back as earlier
as 1881)   However, it should be noted that the behavior described of the
monkey's who underwent temporal lobe surgery, could not be produced if the
lesions were too restrictive in size (i.e. small) or too a single
hemisphere.  It required significant ablation and removal of the temporal
lobe.  Thus, the reference employed by the previous post that the amygdala
"(is) not the whole story" is entirely precise.  The emergence of the
symptomology of Kluver-Bucy syndrome reflects discrete multifocal
alterations in the pattern of neuronal connectivity and the accompanied
changes to neuronal functioning throughout a variety of structures. All of
this could result in the conspicuous change in "normal" behavior.


"k p Collins" <kpaulc@[----------]earthlink.net> wrote in message
news:th7Rb.26004$i4.25078 at newsread1.news.atl.earthlink.net...
> While this or that study rediscovers it, all of this
> stuff has been long-known.
> I should look-it-up before 'spouting-off', but I 'think',
> if you search on "Cluver-Bucy Syndrome", you'll see
> what I mean.
> Anyway, it was all established before I began
> working in Neuroscience in 1971.
> There were a lot of correlated studies done in
> Monkey [hypersexuality post amygdalotmy,
> which means that, with respect to sexuality,
> the amygdala is a "supersystem configuration"
> mechanism [AoK, Ap5], =not= the 'whole
> story'.
> Cheers, ken [k. p. collins]
> "James Michael Howard" <jmhoward at arkansas.net> wrote in message
> news:4nk810974c5foigcsui90s71j9us98ro7p at 4ax.com...
> > The Amygdala and Human Evolution.. A connection????
> >
> > In 1985, I copyrighted "A Theory of the Control of the Ontogeny and
> Phylogeny of
> > Homo sapiens by the Interaction of Dehydroepiandrosterone and the
> Amygdala."  I
> > had difficulty researching my ideas regarding DHEA and the amygdala, so
> > focused on DHEA.  Anyway I was pleased to find the following, new
> which
> > shows that I may have been on the right path in my selection of the
> amygdala.
> >
> > Annals of Neurology 2004 Jan; 55(1): 87-96.
> > The amygdala and sexual drive: Insights from temporal lobe epilepsy
> surgery.
> >
> > Baird AD, Wilson SJ, Bladin PF, Saling MM, Reutens DC.
> >
> > School of Behavioural Science, Department of Psychology, University of
> > Melbourne, Melbourne, Australia.
> >
> > The aim of this study was to explore the relationship between the
> and
> > human sex drive. We compared amygdalar volume in groups of patients with
> or
> > without sexual changes after temporal lobe resection and in age-matched
> > neurologically normal subjects. Forty-five patients with intractable
> temporal
> > lobe epilepsy who underwent surgical resection in the Comprehensive
> Epilepsy
> > Program at the Austin and Repatriation Medical Centre completed a
> semistructured
> > interview and questionnaire relating to sexual outcome after surgery.
> Volumetric
> > analyses of both amygdalae were conducted on the patients' preoperative
> > T(1)-weighted magnetic resonance imaging scans and those of 46
> neurologically
> > normal controls. Patients who reported a postoperative sexual increase
> a
> > significantly larger amygdalar volume contralateral to the site of their
> > resective surgery than patients with a sexual decrease or no change than
> control
> > subjects. There was a significant positive relationship between
> contralateral
> > amygdalar volume and the maximum degree of sexual change. We have
> demonstrated a
> > relationship between contralateral amygdalar volume and sexual outcome
> > patients undergoing temporal lobe resection. This finding provides
> evidence for
> > an important role of the amygdala in regulating human sexual behavior. A
> larger
> > contralateral amygdala may contribute to the expression of increased or
> improved
> > sexuality after temporal lobe resection
> >
> > James Michael Howard
> > www.anthropogeny.com

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