Rats may be able to recall past events from memory, according to a study by neuroscientists at Indiana University. The discovery might help advance the development of drugs used to treat Alzheimer's disease.
Professor Jonathon Crystal, who led the study, said most preclinical studies on possible new Alzheimer's drugs look at how compounds affect spatial memory, but it is episodic memory whose loss causes the effects of the disease.
"We're interested in episodic memory — and episodic memory replay — because it declines in Alzheimer's disease, and in aging in general," said IU Ph.D. student Danielle Panoz-Brown, who also worked on the study.
Spatial memory is how a person records information on where they are and the environment around them. Episodic memory lets a person recall events that have already happened. For example, that's how a person remembers what they did before they left for work and whether they locked the front door. Being able to replay events in order is called "episodic memory replay." People wouldn't be able to make sense of most scenarios if they couldn't remember the order in which they occurred, Crystal said.
"We're trying to push the envelope of what can now be studied in nonhuman animals," Crystal said. "We've known for a long time that animals have memories, and even that they have episodic memories."
The important distinction, he said, is that they now know animals can recall events in the specific order they occurred.