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.
Dept of Psychology
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
