How The Brain Turns
Short-Term Memories Into
Permanent Ones
By Will Boggs, MD
5-17-1
NEW YORK (Reuters Health) - For the first
time,
scientists have identified a protein in
the brain that
is required for turning short-term
memories into
permanent ones.
Initial learning takes place in one part
of the brain,
the hippocampus, but these first
experiences become
permanent memories only after
reinforcement in the
brain's outermost layer, the cortex,
according to Dr.
Alcino J. Silva from the University of
California at
Los Angeles and associates.
Until now, little was known about the
processes
involved in making that translation.
The authors tested mice that had only half
the normal
levels of a protein called alpha-CaMKII.
The total
absence of this protein results in
learning and memory
problems. The model they used enabled the
scientists to
separate the short-term learning functions
of the
hippocampus from the permanent memory
functions of the
cortex.
Mice with less alpha-CaMKII learned tasks
as well as
normal mice, the authors report in the May
17th issue
of Nature, but--unlike normal mice--they
forgot the
tasks within a few days. The timing of
this memory
loss, they say, matches the shift in the
memory
function from the hippocampus to the
cortex.
Using sophisticated measurements of the
electrical
activity of the brain, the researchers
also showed that
mice deficient in alpha-CaMKII have
disruptions in the
type of activity usually associated with
the
development of memories. Again, these
disruptions were
present in the cortex, but not in the
hippocampus.
``We have uncovered new insights into the
function of
this protein (it is involved in the
formation of
permanent memories in the cortex), but our
work also
speaks to the sites and mechanisms
required to
establish permanent memories in the
brain,'' Silva told
Reuters Health. ``This information will be
essential to
design therapies to memory
disorders.''
``Our article reports the first molecular
and cellular
information into one of memory's most
mysterious
processes: how we establish the memories
that the brain
retains, the ones that become our oldest
memories,''
Silva concluded. ``These are very specific
(and
hopefully important) clues into this
mysterious and
wonderful process.''
SOURCE: Nature
2001;411:309-313,248-249.
Mike Lee,
MA [EMAIL PROTECTED]
Dept of
Psychology http://home.cc.umanitoba.ca/~mdlee
University of Manitoba
Winnipeg, MB Canada
"Our situation on this Earth seems strange.
Every one of us appears here involuntarily,
and uninvited, for a short stay without knowing why. To me it is
enough to wonder at the secrets."
-- Albert Einstein
"Men are probably nearer the central truth in their
superstitions than in
their science." --Henry David Thoreau