Memories have been blocked and recovered in experiments that hold out the prospect of "artificial limbs for the mind" to combat Alzheimer's and other brain diseases. The experiments were done on rats and demonstrated that when an electronic switch implanted in the brain is flipped, the ability to retrieve memories returned.
Such artificial stimulation of the memory processes in humans, scientists believe, offers a potential treatment against Alzheimer's and other degenerative diseases, strokes and brain injuries.
The rats used in the experiments first learnt to perform a task which involved pressing a particular lever to get water and were then given drugs which meant they could no longer remember how to do it. Implanted electronic switches were activated, and by stimulating activity between two major areas of the hippocampus, the rats were able to remember what they had to do to get a drink, demonstrating to the researchers that it is possible to create prosthetic devices for the brain.
"Flip the switch on, and the rats remember. Flip it off, and the rats forget," said Professor Theodore Berger, of the University of Southern California, one of the scientists involved with the project.
The neural stimulation provided by the devices was also found to improve the rats' memories if used when their brains were functioning normally, according to the paper published in the Journal of Neural Engineering. The study builds on previous findings about the way the hippocampus operates and its role in the way people learn.