A SINGLE INTRASEPTAL INJECTION OF NERVE GROWTH-FACTOR FACILITATES RADIAL MAZE PERFORMANCE FOLLOWING DAMAGE TO THE MEDIAL SEPTUM IN RATS

Rats were trained on a radial maze and then given electrolytic lesions of the MS followed by a single intraseptal injection of 5 mu g of NGF . Three days later they were re-tested on the maze. They were also pos t-operatively tested for hyperemotionality. MS lesions severely impair ed performance on the radial maze and produced increased emotionality. MS lesions also produced a general decrease in hippocampal high affin ity choline transport and acetylcholinesterase staining, which was not affected by NGF administration. NGF treatment ameliorated the behavio ral deficit in the radial maze but had no effect on the hyperemotional ity. In order to determine whether the NGF was working to restore prev iously learned spatial abilities, the type of learning strategy used b y the animals was also assessed. NGF treatment did not restore previou sly learned spatial strategies but facilitated recovery of alternative learning strategies. The reduction in cognitive deficit was also para lleled by reduced ventricular enlargement in the NGF treated rats. The present results suggest that a single injection of NGF can produce a long-lasting improvement on a cognitive task and reduce some of the in jury-induced, secondary reactive changes that occur following electrol ytic MS lesions.