Focal hippocampal gain of NGF function elicits specific septal cholinergicreorganization

THE influence of NGF on the neuroanatomic substrate(s) subserving learning and memory was probed by somatic mosaic analysis. NGF XAT mice underwent un ilateral hippocampal delivery of virus vector expressing cre recombinase to produce focal NGF gain of function mosaics. Activated mice expressing incr eased NGF, but not control mice transduced with the LacZ gene showed reorga nization of the septohippocampal projection assessed by retrograde labeling with Fluorogold (FG). Mice mosaic for NGF function demonstrated in ipsilat eral medial septum and diagonal band significant increases in FG-labeled ce ll 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 . (C) 1999 Lippincott Williams & Wilkins.