NARSAD Grantee Identifies Neurotransmitters that Lead to Forgetting

Ron Davis, Ph.D. Expert on Memory from Scripps Research Institute
Ron Davis, Ph.D.

NARSAD Distinguished Investigator Grantee, Ron Davis, Ph.D., is the lead author of a new study that identified a mechanism essential for both forming memories and eliminating them after memories have formed. Dr. Davis is chairman of the Scripps Research Department of Neuroscience.

According to Dr. Davis, "this study focuses on the molecular biology of active forgetting," Until now, the basic thought has been that forgetting is mostly a passive process. Our findings make clear that forgetting is an active process that is probably regulated."

Expressed widely throughout the brain, dopamine is a message-carrying molecule called a neurotransmitter, which is involved in a number of regulatory processes related to movement and aspects of cognition such as attention, memory and learning. Dr. Davis and his colleagues demonstrated that a small subset of dopamine neurons actively regulate the acquisition of memories and the forgetting of these memories after learning, using a pair of dopamine receptors in the brain.

Their findings were based on studies of Drosophila or fruit flies which have ideal properties for brain research as the brain of the fruit fly has about 100,000 neurons compared to human brains which have about 100 billion neurons.  And unlike mammalian brains, researchers can remove a fly's brain and examine it under the microscope while it is still functioning.  This allows researchers the ability to isolate neurons that have different functions and watch them fire -or send signals- to other neurons when stimulated.

In their experiment, Dr. Davis put the flies in situations where they learned that certain smells were associated with either a positive reinforcement like food or a negative one, such as a mild electric shock. The scientists then observed changes in the flies' brains as they remembered or forgot the new information.

The study was published in the May 10th edition of the journal Neuron.

Read more about this brain research