neuroscience training?

ken kpaulc at earthlink.net
Fri Mar 12 06:47:49 EST 2004


The Experimenters' results are interesting and Important,
but their conclusions are False.

It's as I discussed in my prior reply in this thread.

More below.

"John H." <johnh at faraway.> wrote in message
news:40511efe at dnews.tpgi.com.au...
> NMF,l,
>
> Have downloaded the file, can forward if you wish; 465k
>
> The Journal of Neuroscience, May 1, 2003 . 23(9):3790 -3795
> Menstrual Cycle-Dependent Neural Plasticity in the Adult
> Human Brain Is Hormone, Task, and Region Specific
> Guille´n Ferna´ndez,1,3 Susanne Weis,1 Birgit Stoffel-Wagner,2 Indira
> Tendolkar,4 Markus Reuber,1 Stefan Beyenburg,1
> Peter Klaver,1 Ju¨rgen Fell,1 Armin de Greiff,5 Ju¨rgen Ruhlmann,6 Ju¨rgen
> Reul,6 and Christian E. Elger1
> Departments of 1Epileptology and 2Clinical Biochemistry, University of
Bonn,
> 53105 Bonn, Germany, 3F. C. Donders Centre for Cognitive Neuroimaging,
> 6500 HB Nijmegen, The Netherlands, 4Department of Psychiatry, University
of
> Cologne, 50924 Cologne, Germany, 5Departments of Neurology and
> Neuroradiology, University of Essen, 45122 Essen, Germany, and 6Department
> of Diagnostic and Therapeutic Neuroradiology, Medical Center Bonn, 53119
> Bonn, Germany
> In rodents, cyclically fluctuating levels of gonadal steroid hormones
> modulate neural plasticity by altering synaptic transmission and
> synaptogenesis.

What they observed is not structural Plasticity, but
'normal' "supersystem configuration" differentials
that're correlated to global TD E/I, of course, in
a way that's correlated to the hormonal differentials
that they were monitoring.

> Alterations ofmoodand cognition observed during the
> menstrual cycle suggest that steroid-related plasticity also occurs
> in humans. Cycle phase-dependent differences in cognitive performance have
> almost exclusively been found in tasks probing lateralized
> neuronal domains, i.e., cognitive domains such as language, which are
> predominantly executed by one hemisphere.

'language' tends, strongly, to 'always' directly-reflect
global TD E/I.

> To search for neural
> correlates of hormonally mediated neural plasticity in humans, we thus
> conducted a functional magnetic resonance imaging study
> measuring brain activity related to a semantic decision task in the
language
> domain. This was contrasted with a letter-matching task in the
> perceptual domain, in which we expected no steroid hormone-mediated
effect.
> We investigated 12 young healthy women in a counterbalanced
> repeated-measure design during low-steroid menstruation and high-steroid
> midluteal phase. Steroid serum levels correlated
> with the volume and lateralization of particular brain activations related
> to the semantic task but not with brain activity related to the
> perceptual task.

Noted in-passing: The perceptual task does not require
the subject to express 'self'. The subject only expresses
recognition of a stimulus that's external to 'self'.

> More specifically, bilateral superior temporal recruitment
> correlated positively with progesterone and medial superior
> frontal recruitment with both progesterone and estradiol serum levels,
> whereas activations in inferior and middle frontal cortex were
> unaffected by steroid levels. In contrast to these specific interactions,
> testosterone levels correlated nonselectively with overall activation
> levels by neural and/or vascular factor(s).

In all three cases, there it is, a physiological 'picture' of
global TD E/I(up)

> In conclusion, our data
> demonstrate steroid hormone responsivity in the adult human brain by
> revealing neural plasticity in the language domain, which appears hormone,
> task, and region specific.

It's not structural plasticity, but dynammically-tuned
"supersystem configuration" variability.

If it was structural plasticity, there'd be a cummulative
effect throughout Life, which would, necessarily, also
exhibit a long-term diminution.

I suggest the Experimenters do periodic long-term follow-ups
with their subjects, and, perhaps, do single-instance studies for
correlates in Women of other ages.

K. P. Collins

> "NMF" <nm_fournier at ns.sympatico.ca> wrote in message
> news:2w44c.28234$hG.351644 at news20.bellglobal.com...
> >
> > "John H." <johnh at faraway.> wrote in message
> > news:405037d3 at dnews.tpgi.com.au...
> > > Last year some
> > > German scientists studied how female brains handle language through
the
> > > course of the menstrual cycle. To their surprise they found noted
> > > differences across the cycle. Not small regionally specific
differences
> > > either, but wholesale changes in left-right balance in language
> production
> > > and comprehension.
> >
> > Hi John, could you find the reference to that study.  I would really
> > appreciate it.
> >
> > Thanks a lot.
> >
> >
> >
> >
>
>





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