REDUCTION OF TRANSIENTLY EXPRESSED ACETYLCHOLINESTERASE ACTIVITY IN DEVELOPING THALAMOCORTICAL PROJECTIONS DOES NOT AFFECT THE MATURE PATTERN OF BASAL FOREBRAIN PROJECTIONS TO VISUAL-CORTEX

Experiments tested the hypothesis that acetylcholinesterase (AChE) activity, expressed transiently in developing thalamocortical projections, serves to limit the growth of basal forebrain cholinergic projections into thalamocortical recipient zones. Newborn rats were subjected to enucleation, a procedure that eliminates transient AChE activity in developing visual cortex. After 3-8 weeks survival, AChE histochemical techniques revealed no alteration in the pattern of AChE positive basal forebrain axons in visual cortex. These data indicate that transient AChE activity in developing sensory cortex does not limit ingrowth of basal forebrain cholinergic axons.