Rats may have a form of “instant replay” in their memory processes that helps them decide their actions, researchers at MIT have found. Their work sheds some new light on the way that both humans and animals learn and remember.

According to one of the study’s authors Matthew A. Wilson, who is the Sherman Fairchild Professor of Neuroscience at the Picower Institute at MIT by gaining a better understanding into the way thoughts and memories are actually structured researchers can in the future hope to understand the effects of such diseases as Alzheimer’s on those processes and move a step closer to a cure.

In Wilson’s lab, rats are monitored by way of the highly accurate recording of the functions of a single neuron located in the hippocampus region of the brain. This is a “seahorse” shaped region which scientists have concluded is responsible for many functions involved in learning and memory.  The animals are monitored while performing tasks, while at waking rest and whilst sleeping.

In his previous work Wilson and colleagues had been able to demonstrate that after a rat had been induced to run through a maze its’ brain would in fact replay the sequence while it was sleeping. This led them to conclude that this was proof of sleep induced learning processes in both human and animal brains.

In his new work Wilson set out to demonstrate that the rat’s brains also do this while the animal is in a conscious state, essentially helping them decide what to do next.

When a rat is placed in a maze and encouraged to negotiate it certain neurons known as “place cells” are activated. By studying these patterns researchers are able to discern at what point of the maze the rat is currently negotiating.

In this study it was found that even when a rat was stationary within the maze the same patterns of activity occurred. According to Wilson this may be the rat equivalent of “thinking”. The patterns are very similar to those seen in the previous study of sleeping rats leading the researchers to think that thinking and dreaming share the same memory activation properties.

The team’s data showed that experiences the rat underwent that may have taken minutes were replayed by their brains in just a fraction of a second. To do this they believe that the brain strings together small pieces of memory to reconstruct a long experience.

In addition by comparing the replay content with a rat’s physical location in a maze they could discern that the rat seemed to actually be considering his next actions, such as whether to go left, right or forwards.