Learning and Memory
We work in collaboration with Gina Poe's lab in the Anesthesiology and Molecular and Integrative Physiology departments of the University of Michigan Medical School. As a rat engages in a spatial learning task, a multi-electrode array records the activity of the surrounding neurons, many of which are CA1 neurons that are later identified as place cells. We examine these recordings using measures based on causal entropy and cross correlation in order to identify changes in dynamic ordering between these cells which may indicate long term potentiation and thus evidence of learning.
Other work involves interaction between excitatory and inhibitory cells in hippocampus and its role during sleep. We use computer simulations of neural networks to investigate possible mechanisms of this interaction and its spatiotemporal features. In addition to models we work on the analysis of experimental data, mainly single cell recordings from rats hippocampus during different phases of sleep.Featured Results
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Causal entropy differences between two pairs of hippocampal neurons. The region external to the gray shaded area represents significance. These examples show significance only when the rat is running in a novel track, i.e. when learning is occurring.
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The change of CEDs between different behavioral segments of a hippocampal learning task. Each segment is relatively self-similar, though the Novel segment is less so. Also, the Novel is more similar to Familiar 1 than Familiar 2. These and other features are suggestive of LTP taking place during the Novel segment. |
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