Shining a light on memory

(NIH/National Institute of Mental Health) Using a flash of light, scientists have inactivated and then reactivated a memory in genetically engineered rats. The study, supported by the National Institutes of Health, is the first cause-and-effect evidence that strengthened connections between neurons are the stuff of memory. The findings add to mounting evidence that the brain represents a memory by forming assemblies of neurons with strengthened connections, or synapses.