The ability to learn and remember is fundamental to all mental processes. In the brain, learning occurs through changing the strength of transmission at the synaptic junctions between nerve cells. Impairments in this function lie at the heart of the cognitive problems seen in many neurological disorders, including Alzheimer’s disease, head injury and stroke. We have discovered a novel form of synaptic plasticity impairment that involves a non-neuronal cell type, astrocytes, that are activated by particular patterns of nerve cell activity. This mechanism may play an important role in maintaining normal levels of brain activity, while its abnormal activation may generate synaptic impairments in Alzheimer’s disease. In this project we will utilise neurophysiological, imaging and genetic approaches to reveal the fundamental mechanisms mediating the impairment in plasticity. Understanding these processes may help identify new molecular targets for therapeutic interventions to rescue diseased memory and cognition.