TORONTO, April 19 /CNW/ - Researchers at The Hospital for Sick Children
(SickKids), Columbia University, UCLA, Harvard Medical School and University
of California, Irvine have found that there is competition between brain cells
during memory formation and that the expression of a particular protein is
involved in the success of a brain cell becoming part of a given memory. This
research is reported in the April 20 issue of Science.
Memories are thought to be created through the strengthening of
connections between brain cells (neurons) to form a memory trace. Each memory
is thought to be supported by a unique memory trace, involving different
populations of neurons. Previous research showed that not all neurons in a
given structure are needed to form or encode a given memory. In fact, these
findings suggested that only a subset of neurons in a given structure were
necessary to encode a particular memory.
"We wondered why one neuron, rather than its neighbour, seemed to be
chosen for inclusion in a particular memory trace," said Sheena Josselyn,
SickKids scientist in Neurosciences & Mental Health, Canada Research Chair in
Molecular and Cellular Cognition and assistant professor of Physiology at the
University of Toronto. "Competition has previously been shown to be important
during brain development, so we wondered whether competition occurred between
neurons during memory formation in the adult brain."
"Our findings show for the first time that competition between neurons
occurs during memory formation. The 'winner' neurons form the memory trace
whereas the 'losers' are excluded from the trace for that particular memory.
Furthermore, we identified a particular protein, called CREB, which influenc
the outcome of this competition."
The research team also found that increasing CREB function in roughly
20 per cent of neurons in a particular structure rescued the memory deficits
in mice in which the CREB gene had been "knocked out". Their next steps are to
determine how many neurons are sufficient to encode a memory and to test other
proteins that may also influence the outcome of neuronal competition during
Over 30 million North Americans suffer from some type of clinically
recognized learning or memory disorder, from inherited forms of mental
retardation to the gradual weakening of memory with age or the ravages of
Alzheimer's disease. In order to develop new treatment or prevention
strategies, the mechanisms underlying normal memory formation must be
Members of the research team were Jin-Hee Han, Adelaide Yiu and Christy
Cole from SickKids, Steven Kushner, Anna Matynia, Robert Brown and Alcino
Sliva from UCLA, Rachael Neve of Harvard Medical School and John Guzowski of
the University of California, Irvine.
This research was funded by the Canadian Institutes of Health Research,
the National Institutes of Health and SickKids Foundation.
The Hospital for Sick Children (SickKids), affiliated with the University
of Toronto, is Canada's most research-intensive hospital and the largest
centre dedicated to improving children's health in the country. As innovators
in child health, SickKids improves the health of children by integrating care,
research and teaching. Our mission is to provide the best in complex and
specialized care by creating scientific and clinical advancements, sharing our
knowledge and expertise and championing the development of an accessible,
comprehensive and sustainable child health system. For more information,
please visit www.sickkids.ca. SickKids is committed to healthier children for
a better world.
For further information:
For further information: Chelsea Novak, Public Affairs, The Hospital for
Sick Children, (416) 813-5045, firstname.lastname@example.org