February 19, 2005

Monkeys, Math Model Crack Memory Mystery

Researchers identify mechanisms behind short-term recall

HealthDay News -- Remembering phone numbers, names at a party, directions to a restaurant: All are tasks that demand short-term, but not necessarily long-term, memory.

Neuroscientists have long puzzled over mechanisms behind short-term, or "working," memory, and now monkeys and a mathematical model may solve the mystery.

Reporting in the Feb. 18 issue of Science, researchers at Cold Spring Harbor Laboratory say they trained macaque monkeys compare sequences of light, fingertip vibrations. The researchers trained the monkeys to remember each sequence and then signal a 'yes' or 'no' answer to the question "Was the first vibration faster than the second?" All the while, the researchers tracked their brain activity in the lab.

According to the investigators, this simple task relies heavily on various steps in the short-term memory -- a "loading phase" (where the stimulus is received by the brain), a "memory phase" (where the information is held), and a "decision phase" (where the brain compares information to make choices).

A mathematical model that predicts how these various phases work to create short-term memory would mark a real advance in the understanding of this phenomenon. In their paper, the Cold Spring Harbor team say they have created just such a model.

According to the researchers, their "mutual inhibition" model, based on neural patterns exhibited by the monkeys, was able to explain all three short-term memory phases.

The model also makes several predictions about the neurological basis of short-term memory. These predictions can be tested, the researchers note, to determine if the model is advancing understanding of brain function and structure.

More information

The Nemours Foundation has more about memory.