Focal hippocampal gain of NGF function elicits specific septal cholinergic reorganization

The influence of NGF on the neuroanatomic substrate(s) subserving learning and memory was probed by somatic mosaic analysis. NGF XAT mice underwent unilateral hippocampal delivery of virus vector expressing cre recombinase to produce focal NGF gain of function mosaics. Activated mice expressing increased NGF, but not control mice transduced with the lacZ gene showed reorganization of the septohippocampal projection assessed by retrograde labeling with Fluorogold (FG). Mice mosaic for NGF function demonstrated in ipsilateral medial septum and diagonal band significant increases in FG-labeled cell bodies (94%), ChAT-labeled cells (55%), double-positive cells (190%) and increased somal size of double-positive cells (56%) than did non-activated mice. These results indicate that reorganization of the cholinergic septal input to a specific hippocampal region is promoted by gain of NGF function.