Dissecting hippocampal circuits  for the encoding of early-life memories
The infant brain is a formidable learning machine. But is it able to encode memories of early-life experiences? Since most of us don’t remember what happened during the first years of our lives, for a long time this question has been open to debate. Recent evidence suggests that, even if we cannot recall them, early-life memories are encoded in the developing hippocampus, persist in a silent state into adulthood, and can affect the acquisition of new information later in life. We know very little about how the infant brain encodes early-life memories, despite the fact that our earliest experiences can stick with us and influence our behaviour as adults. How can the infant hippocampus produce long-lasting memory traces when its circuits are not yet mature? Why can’t we remember early-life memories? And how can infant memories have long-lasting effects if we can’t recall them? To answer these questions, in the following project I propose to study memory processes in the developing brain using the mouse as a model organism. I will implement a combination of genetics, viral tagging, calcium imaging, and opto- and chemogenetic methodologies, in association with behavioural paradigms, to track in vivo the activity of a large number of neurons as the brain matures, and to gain fundamental insights into the early functions of the mammalian memory system. The aims of my proposal are: 1. to understand how the infant hippocampus produces neuronal ensembles to represent early-life experiences; 2. to identify and dissect the neural circuits encoding infant memories; and 3. to unravel how neurons supporting silent memories created during infancy influence learning processes in adults. By bridging developmental, systems, and behavioural neuroscience, my ambition is to understand how the developing brain encodes memories of early-life experiences, and how infant memories influence the operations of higher-order cognitive functions later in life.