Science + Technology

UCLA Researchers Discover Key to Memory Storage in Brain; Research Suggests New Approach to Treating Alzheimer’s, Brain Injury


For years, scientists have known little about how the brainassigns cells to participate in encoding and storing memories. Now a team ofresearchers from UCLA and the University of Toronto has discoveredthat a protein called CREB controls the odds of a neuron playing a role inmemory formation.

The findings, reported in the April 20 edition of thejournal Science, suggest a new approach for preserving memory in peoplesuffering from Alzheimer's and certain brain injuries.

"Making a memory is not a conscious act," said Alcino Silva,principal investigator and a professor of neurobiology and psychiatry at theDavid Geffen School of Medicine at UCLA."Learning triggers a cascade of chemicals in the brain that influencewhich memories are kept and which are lost.

"Earlier studies have linked the CREB protein to keepingmemories stable," he said. "We suspectedit also played a key role in channeling memories to brain cells that are readyto store them."

Silva, a member of the UCLA Brain Research Institute, andhis colleagues used a mouse model to evaluate their hypothesis. They implantedCREB into a virus, which they then introduced into some of the cells in theanimal's amygdala, a brain region critical to emotional memory.

Next, they tested the ability of the mouse to recall aspecific cage it had visited before. The cage was outfitted with patternedwalls and a unique smell.

To visualize which brain cells stored the mouse's memoriesabout the cage, the scientists tracked a genetic marker that reveals recentneuron activity. When the team examined the amygdalas of the mice after theexperiment, they found substantial amounts of CREB and the marker in neurons.

"We discovered that the amount of CREB influences whether ornot the brain stores a memory," Silva said. "If a cell is low in CREB, it isless likely to keep a memory. If the cell is high in CREB, it is more likely tostore the memory."

The human implications of the new research could proveprofound.

"By artificially manipulating CREB levels among groups ofcells, we can determine where the brain stores its memories," Silva said. "Thisapproach could potentially be used to preserve memory in people suffering fromAlzheimer's or other brain injury. We may be able to guide memories into healthycells and away from sick cells in dying regions of the brain."

Our memories define who we are, so learning how the brainstores memory, Silva said, is fundamental to understanding what it is to behuman.

"A memory is not a static snapshot," he said. "Memoriesserve a purpose. They are about acquiring information that helps us deal withsimilar situations in the future. What we recall helps us learn from our pastexperiences and better shape our lives."

The study was funded by the National Institute on Aging andNARSAD: The Mental Health ResearchAssociation. Silva's co-authorsincluded Steven Kushner, Anna Matynia and Robert Brown of UCLA; SheenaJosselyn, Jin-Hee Han, Adelaide Yiu and Christy Cole of the University ofToronto; Rachel Neve of Harvard University; and John Guzowski of the Universityof California, Irvine.



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