A light pulse at the level of brain neural connections is able to weaken or reactivate a memory.

The discovery comes from a Californian team of researchers led by Robert Malinow from the University of San Diego and funded by the National Institute for Health.

The Californian researchers optically stimulated a group of genetically modified synapses in the brain of a rat to make them sensitive to light and at the same time sent an electric shock to the animal’s foot.

The animals learned to associate the stimulation of the optic nerve with pain showing reactions of fear when these nerves were touched. Subsequently, in the absence of stimulation, the rats showed no fear as the combination with pain was canceled. Thus resulting in exciting applications in the medical field for mnemonic deficit disorders, such as dementia and Alzheimer’s.

Robert Malinow observed that the beta amyloid peptide that accumulates in the brains of persons with Alzheimer’s disease weakens the synaptic connections in a manner similar to the way the rats were stimulated. “Since our work – said the researcher – shows that we can reverse the processes that weaken synapses, we could potentially counteract some of the effects of beta-amyloid in Alzheimer’s.”