The retention of memory and creation of knowledge: a neurobiological model
Richard G Morris
University of Edinburgh
Director of the Centre for Cognitive and Neural Systems and Professor of Neuroscience
Memory is central to our life and identity. Our brains make memory traces automatically as we go about our daily life. We also forget a lot - it’s natural. Automaticity of synaptic potentiation, achieved by event-related triggers of alterations in the synaptic connectivity between memory processing cells in the brain, ensures that the system does not have to ‘decide’ in an instant what to keep and what to lose. A grace period prevails. The risk of the system becoming ‘saturated’ with too much information is avoided, because ongoing decay of memory traces serves the essential subtractive function of keeping things within range. But what memory traces get kept and which are lost? Key determinants include the processes of cellular and systems consolidation, in turn affected by events at the time of memory encoding (salience etc), but also events around the same time but which happen before or after. For example, novelty can promote the selection of what the brain keeps, including of trivial and unsurprising events that happen around the time of surprise; we have the beginnings of a neurobiological account in terms of synaptic tagging and capture of how this “flashbulb mememory” happens. Of what is left at the end of the day, the brain consolidates what most interests us by somehow assimilating what fits best with our frameworks or schemas of existing knowledge. So - paradoxically - familiarity matters too. Animal experiments that I shall describe bear on these issues, but I shall endeavour to set these in a broader intellectual context that will hopefully be of interest to a wider group of people.