Interneuron plasticity ensuring long-term memory formation

Understanding learning and memory processes is of fundamental importance to the study of brain function and provides valuable insights for disorders where these processes are disturbed. The current study of Pico Caroni from the Friedrich Miescher Institute for Biomedical Research, identifies plasticity induced at the time of learning, which is necessary during 12-14 hours after acquisition for long-term memory formation. It shows how learning-induced changes in parvalbumin basket cells are sustained by dopamine signaling for several hours and how basket cell plasticity 12 hours after the learning experience is required for enhanced network activity and long-term memory formation. Several pieces of the long-term memory formation puzzle have been known, some for a while: the brain area called the hippocampus plays a role; the neurotransmitter dopamine is crucial; a time window 12 hours after learning is important; ripples - oscillations of large neuronal networks between different brain regions - help consolidate a memory; and recently Pico Caroni and his research group at the FMI showed that the plasticity of local so called parvalbumin basket cells modulates learning and memory. However, how these pieces fit together and lead to long-term memory had remained elusive. In a study published , Pico Caroni - a Group leader at the FMI and Professor at the University of Basel - and the two first authors Smitha Karunkaran and Ananya Chowdhury beautifully dissected the interplay of these molecules, cells, neuronal networks, time points and phenomena in long-term memory formation and gained interesting new insights.