Visualizing Changes in Circuit Activity Resulting from Denervation and Reinnervation Using Immediate Early Gene Expression

摘要: We describe a novel strategy to evaluate circuit function after brain injury that takes advantage of experience-dependent immediate early gene (IEG) expression. When normal rats undergo training or are exposed environment, there is strong induction IEG expression in forebrain regions, including the hippocampus. This identifies neurons engaged during experience. Here, we demonstrate diminished young adult (120-200 gm), specifically unilateral lesions entorhinal cortex (EC), and then recovers with time course consistent reinnervation. In situ hybridization techniques were used assess activity-regulated cytoskeleton-associated protein Arc at various times lesion (4, 8, 12, 16, 30 d). One group was allowed explore complex environment for 1 hr; control operated animals remained their home cage. unoperated animals, exposure induced mRNA levels most pyramidal CA1, many CA3, small number dentate granule cells. characteristic pattern absent points EC (4 8 d) but recovered progressively later points. The recovery occurred approximately same as reinnervation gyrus result postlesion sprouting. These results document approach quantitatively assessing polysynaptic circuits trauma.