Putting episodic memory in context: Lateral entorhinal cortex and associative recognition memory
James Ainge (School of Psychology and Neuroscience, University of St Andrews)
Lecture C42, Biomedical Sciences Building
Snapshots: Seminars in Physiology, Neuroscience and Pharmacology
Hosts: Clea Warburton / Gareth Barker
Abstract: Episodic memory and navigation rely on neural mechanisms within the hippocampal-entorhinal circuitry. Models of this network suggest that item or object information from lateral entorhinal cortex (LEC) is combined with spatial information from medial entorhinal cortex (MEC) to form representations of events and locations within the hippocampus. Support for this model comes from studies showing numerous types of spatial representation in MEC including grid cells, head directions cells, border/boundary vector cells and speed cells. The function of LEC, however, is less well understood. LEC does not process spatial information in the simple environments used in standard place cell experiments. However, there are populations of LEC neurons that produce spatial responses when objects are introduced and moved within familiar environments. My recent work has examined the hypothesis that LEC is needed to integrate object information into a spatial and contextual local framework. I will present data showing that activation levels in LEC increase when rodents demonstrate a memory for objects within a specific context. I will go on to show that LEC is not needed for recognition of individual features of an environment but is needed to associate multiple features together. I will present a possible mechanism for this by showing that CA1 place cells receiving LEC input are much more responsive to objects manipulations than those receiving MEC input. These data suggest that the LEC input is preferentially involved in processing how local features of an environment are integrated. Finally I will present data using new genetic and molecular tools that allow us to dissect the functional properties of the pathway from LEC to hippocampus in more detail.