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Brains [15 Jun 2001|02:22pm]
From: "J. R. Molloy" <jr@shasta.com> | Block Address
Date: Fri, 15 Jun 2001 10:14:20 -0700
Reply-to: Virtropy-owner@yahoogroups.com
Subject: [Virtropy] Too Much Thinking Exhausts Brain

Thinking 'drains the brain'
http://news.bbc.co.uk/hi/english/health/newsid_1368000/1368912.stm
Scientists have come up with proof that too much thinking can be
exhausting.
The impact of straining the grey matter is likely to be more pronounced
in
older people.
A team from the University of Virginia in the US carried out research
on rats.
They found that increased memory load drains glucose from a key part of
the
brain in the animals.

The effect was more dramatic in older rats, whose brains also took
longer to
recover.
Researcher Professor Paul Gold said the findings may have important
implications for the way schools schedule classes and meals.
He believes they may also help scientists to develop a better
understanding of
age-related deficits in memory and learning.

Fellow researcher Dr Ewan McNay said: "The brain runs on glucose.
"Young rats can do a pretty good job of supplying all the glucose that
a
particular area of the brain needs until a task demanding that brain
area
becomes difficult.

"In older rats, even on tasks that cause no glucose drainage in young
rats, we
see big problems in supplying the brain with glucose. This correlates
with a
big deficit in performance. A lack of fuel affects the ability to think
and
remember."

Glucose, found in many foods and supplied from the bloodstream, is the
main
source of energy for brain.
It has long been thought that, unless a person is starving, the brain
always
receives an ample supply of glucose.
However, Professor Gold and Dr McNay measured glucose levels in the
brains of
rats as they negotiated their way through a maze.

They found that in a brain area concerned with memory for location the
demand
for glucose was so high that levels fell by 30%.
However, levels stayed constant in other brain areas that played no
role in
spatial memory.

In a follow up study, the researchers showed that in older rats glucose
levels
in the active brain areas dropped by 48% during the maze task.
They also found that in the older animals glucose supply did not return
to
normal until 30 minutes after the task was completed. In young rats
recover
was immediate.

======================

SCIENTIFIC AMERICAN
A Mind for Consciousness
Somewhere in the brain, Christof Koch believes, there are certain
clusters of
neurons
that will explain why you're you and not someone else

LOS ANGELES--Prominent on Christof Koch's desk is a white ceramic
phrenology
bust, its skull divided by glazed black lines into arbitrary regions.
The
maverick neuroscientist assures me that I need not worry about any
caliper
exam; he is as bemused as the rest of us by Lorenzo Fowler's
19th-century
phrenological propaganda that cortical areas correspond to such
personal
attributes as "love of country" and "secretiveness." But Koch
appreciates the
early brain map as a reminder that he's looking for "a discrete set of
neurons
that might be in 20 different areas but share some set of properties
that are
responsible for generating consciousness."

Koch, 44, directs the computation and neural systems program at
Caltech. He
arrived here in 1986, a time when consciousness research was still
considered
career suicide even for established brain researchers. But high-profile
attention to the subject by Nobelists Gerald M. Edelman and Francis
Crick,
coupled with advances in functional brain imaging, has elevated the
field--and
its investigators--to respectability.

Full text:
http://www.sciam.com/2001/0701issue/0701profile.html



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