Carrol Cox wrote:

> This comes from the headline; Would it have been composed by those
> who did the research or by someone in their public affairs office or
> whatever. "Indelible" strikes a wrong note. As though the brain were
> steel and the impression inscribed with acid.  But I'm no
> neuroscientist and can't judge for myself.

typically, these kinds of reports are written by public affairs people
in the university or research facility news divisions, as is this one:

  http://www.hhmi.org/news/kandel3.html

as is clear from the news article, the author (unsigned) interviewed
Kandel and others for the article.

in regards to the use of the term "indelible", its pretty clear from
the article itself that the protein in question is actually operates
as an __inhibitor__ of laying fear traces in the brain. Mice with a
__reduced__ level of Grp gene __receptor__ were more prone to learning
from fearful situations. which is why the abstract (below) refers to a
negative-feeback loop.


The abstract for the paper is naturally quite a bit "tamer":


   We identified the Grp gene, encoding gastrin-releasing peptide, as
   being highly expressed both in the lateral nucleus of the amygdala,
   the nucleus where associations for Pavlovian learned fear are
   formed, and in the regions that convey fearful auditory information
   to the lateral nucleus. Moreover, we found that GRP receptor (GRPR)
   is expressed in GABAergic interneurons of the lateral nucleus. GRP
   excites these interneurons and increases their inhibition of
   principal neurons. GRPR-deficient mice showed decreased inhibition
   of principal neurons by the interneurons, enhanced long-term
   potentiation (LTP), and greater and more persistent long-term fear
   memory. By contrast, these mice performed normally in
   hippocampus-dependent Morris maze. These experiments provide
   genetic evidence that GRP and its neural circuitry operate as a
   negative feedback regulating fear and establish a causal
   relationship between Grpr gene expression, LTP, and
   amygdala-dependent memory for fear.


perhaps there are neuroscience people here who could explain this in
more detail? i'm just summarizing what i understand from a first
reading.

les schaffer