Brain energy expenses

John E. Anderson jander at
Sat Aug 19 10:26:41 EST 2000

Richard Norman wrote:
> And the imaging techniques are nowhere near the resolution of seeing
> individual cells, so that the exact "type" of cell involved in the activity
> is hard to detect without making electrical recordings from single
> cells -- an impossible task to monitor huge number in the brain, not to
> mention being extremely invasive.

I wonder if that might be about to change?  There is an article in the
August 2000 issue of Scientific American ("Gene Scenes" by Trisha Gura,
p 20), which reports on work presented by Thomas J. Meade et al of
Caltech at a National Academy of Engineering meeting in Cleveland in
May.  Meade's group has developed molecular cages that can hold
gadolinium ions, and that can be opened in response to certain
conditions, which results in a strengthening of the MRI signal wherever
the gadolinium is exposed.  The title of the article refers to the
visualization of the expression of a certain gene in frog embryos by
having the cages opened by the activity of the enzyme encoded by the
gene.  But apparently Meade's talk at the meeting dealt with progress in
making a gadolinium "basket" that opens and shuts in response to
intrinsic calcium levels.  Since the resolution of the MRI can be
"tweaked", according to the article, down to about 10 microns, which is
on the order of the size of a neuron, it seems like it might be possible
to visualize activity in individual cells.

Does anyone know any more about Meade's work, or similar work by other

John E Anderson PhD
Department of Natural Sciences
University of North Florida
4567 St Johns Bluff Road South
Jacksonville FL 32224

jander at

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