The main focus of the lab is to try and understand the neural mechanisms that support our ability to remember the things that have happened to us – episodic memory. We are approaching this question using a number of different methodologies and experimental subjects from examining firing patterns of individual neurons in lab rats to looking at children’s ability to remember what has happened to them in their everyday lives. We are also applying this work by using our knowledge of mammalian memory networks to help test therapeutic strategies for disorders of memory such as Alzheimer’s disease. Current on-going research projects in the lab include:
Functional dissociation within Entorhinal cortex
While it is well known that the hippocampus supports episodic memory in humans and animals our understanding of how the network of structures surrounding the hippocampus contributes to this cognitive function is less well understood. In recent years we have been using single unit recording, immediate early gene imaging and lesion techniques to examine the role of one of the main interfaces between the hippocampus and neocortex, the lateral entorhinal cortex (LEC) in episodic memory.
Novelty vs. Familiarity
In recent years a lot of rodent research has used the object recognition paradigm to assess memory. This works by making use of rodents’ natural propensity to explore novel objects and assumes that memory for familiar objects supports this novelty seeking behaviour. In current experiments we are adapting rodent tasks for humans and vice versa to ask whether we are testing the same cognitive processes in both species.
Time vs. context
How do we remember specific events? How is it possible that we can remember hundreds of very similar events that occur in the same location (how many meetings have I had in my office?!)? One way of disambiguating events is to encode the time at which they happened as this is a unique piece of information that can separate each memory from other memories. However, humans are not very good at remembering specific times and dates and as such we rely on other contextual cues that were present during the event (who was there, what the weather was like). Current experiments are asking which neural mechanisms allow is to remember time and contextual information from specific experiences. We are also asking whether context is used by young children to remember events and whether other species (chimpanzees and capuchin monkeys) also use this strategy.
It has been suggested that the main function of the episodic memory system is to allow us to mentally travel in time. This allows us to relive things that have happened to us but also allows us to imagine events in the future. If this is the case then we would expect the same systems in the brain to support both episodic memory and episodic future thinking and for these cognitive functions to come online at the same time in development. Current experiments are examining how single neurons in the rodent hippocampus encode intended future behaviours and whether children develop the capability to remember the past and imagine the future at the same time.
Leptin and episodic memory
Recent studies have suggested that irregularities in the system controlling the hormone leptin are linked with Alzheimer’s disease (AD). Leptin levels are reduced in AD patients and leptin has been shown to reduce b-amyloid (Ab) and tau phosphorylation, 2 hallmarks of AD pathology, in animal models of AD. However, we do not know how leptin affects the debilitating cognitive decline in AD which is characterised by deficits in memory, attention, language and spatial orientation in its final stages. Current experiments are examining whether leptin acts on the systems that support episodic memory which is the first cognitive function to be impaired in the disorder.