Memory encoding in the hippocampus

Episodic memories are comprised of distinct elements such as where events happened, the details of the event itself, and the emotional state at the time the event occurred, that are combined to create a unified memory. The hippocampus is crucial for the formation and recall of episodic memories, but exactly how distinct elements of episodic memories form in the hippocampus and become combined is still unknown. In my lab we use a number of approaches to record and manipulate the activity of large ensembles of neurons while mice are engaged in memory related tasks. We also record the activity of individual axons coming from a number of brain regions such as the ventral tegmental area and the locus coeruleus, and from individual dendrites of pyramidal neurons in the hippocampus. Neuromodulatory circuits such as these carry information about the animal's internal state during memory formation and recall, an element that needs to be integrated with other streams of information in the hippocampus. Using these approaches along with methods to manipulate the activity of these circuits and cells, we are trying to determine how the hippocampus forms and recalls memory representations and how inputs from other regions influence this process. Our ultimate goal is to create a unified theory of memory formation and recall that takes into account data from all levels of analysis, from synapses to ensembles to circuits, all derived from data collected during behavior in memory related tasks. 

Dr. Mark Sheffield is an assistant professor in the Department of Neurobiology at the University of Chicago.

The seminar is free and open to the public.