The effect of synaptic plasticity on spatial representation and navigation
Ward, Kathryn Ruth
Cox, Steven J.
Master of Arts
Synaptic plasticity, or the change in weight of the connections between cells, is a key mechanism underlying the brain's spatial representation and navigation functions. Experimentalists have shown that grid cells in the medial entorhinal cortex fire in hexagonal patterns within an environment, or set of visual cues. Grid cells provide the input for place cells, which fire primarily at one location in the environment and are found in the hippocampus, a region essential for both learning and memory. I have built a computational model to examine how synaptic plasticity affects the interactions among grid cells and place cells. This work demonstrates that a rate-based plasticity model drives the weights from grid cells to place cells to such a distribution that place cells form single firing fields. Furthermore, a spike-timing-dependent plasticity model applied to the connections among place cells causes place fields to shift backward as observed experimentally.