How the brain’s ’memory replay’ goes wrong in Alzheimer’s diseaseMemory dysfunction in Alzheimer’s disease may be linked to impairment in how the brain replays our recent experiences while we are resting, according to a new study in mice by UCL scientists. "We wanted to understand how the function of brain cells changes as the disease develops, to identify what’s driving these symptoms. The replay process, which occurs in the brain’s hippocampus, involves place cells firing in rapid sequences during rest. Place cells - discovered by Nobel prize-winning UCL neuroscientist Professor John O’Keefe - are neurons (brain cells) that represent specific locations. When we visit somewhere, particular place cells fire, and as we move the cells fire in a sequence.