Scientists at the Salk Institute in La Jolla have created a new model of memory that explains how neurons retain select memories a few hours after an event.

This new framework provides a more complete picture of how memory works, which can inform research into disorders liked Parkinson’s, Alzheimer’s, post-traumatic stress and learning disabilities.

Salk Institute researchers Cian O’Donnell, left, and Terrence Sejnowski. Photo courtesy of the Salk Institute for Biological Studies

The work is detailed in the latest issue of the scholarly journal Neuron.

“Previous models of memory were based on fast activity patterns,” said Terrence Sejnowski, holder of Salk’s Francis Crick Chair and a Howard Hughes Medical Institute Investigator. “Our new model of memory makes it possible to integrate experiences over hours rather than moments.”

Over the past few decades, neuroscientists have revealed much about how long-term memories are stored. For significant events—for example, being bitten by a dog—a number of proteins are quickly made in activated brain cells to create the new memories. Some of these proteins linger for a few hours at specific places on specific neurons before breaking down.

This series of biochemical events allow us to remember important details about that event—such as, in the case of the dog bite, which dog, where it was located and so on.

One problem scientists have had with modeling memory storage is explaining why only selective details and not everything in that 1-2 hour window is strongly remembered. Sejnowski and first author Cian O’Donnell, a Salk postdoctoral researcher, developed a model that bridges findings from both molecular and systems observations of memory to explain how this 1-2 hour memory window works.

The new model also provides a potential framework for understanding how generalizations from memories are processed during dreams.

“During sleep there’s a reorganizing of memory—you strengthen some memories and lose ones you don’t need anymore,” says O’Donnell. “In addition, people learn abstractions as they sleep, but there was no idea how generalization processes happen at a neural level.”

By applying their theoretical findings on overlap activity within the 1-2 hour window, they came up with a theoretical model for how the memory abstraction process might work during sleep.

The Salk Institute for Biological Studies is one of the world’s preeminent basic research institutions. Founded in 1960 by polio vaccine pioneer Jonas Salk, the institute is an independent nonprofit organization and architectural landmark.

— From a Salk Institute press release

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Chris Jennewein

Chris Jennewein is Editor & Publisher of Times of San Diego.