THE DYNAMICS OF ARC EXPRESSION IN NEURONAL NETWORKS FOR LONG-TERM MEMORY CONSOLIDATION

Abstract

Arc/Arg3.1 (activity-regulated cytoskeleton-associated protein/activity-regulated gene 3.1) is an immediate- early gene shown to be important in long-term memory formation and has been utilised as a cellular marker of the memory engram. However, limited information is known about the dynamics of Arc expression in neuronal networks. Using an established method of chemical LTP induction in cultured hippocampal neurons, I showed that there was an increased level of Arc expression, together with a trans-cellular translocation of Arc from neurons to astrocytes. Arc expression also correlated with effects of chemical LTP induction in network refinement, with connections containing Arc-positive neurons being selectively refined. Overall, the work in this thesis supports the hypothesis that Arc is involved in mechanisms of plasticity not only on a cellular level but also on the network level, across different cell types and in sculpting network connectivity patterns in response to stimuli.