TIME-COURSE OF MOSSY FIBER SPROUTING FOLLOWING BILATERAL TRANSECTION OF THE FIMBRIA FORNIX/

LESIONS Of the fimbria/fornix (FF) lead to a variety of epileptiform c hanges in hippocampal activity. In epilepsy, as well as in several exp erimental preparations of epilepsy, aberrant sprouting of the dentate gyrus messy fibers (MF) is observed and has been hypothesized to play a critical role in the generation of seizure activity. We therefore so ught to determine whether MF sprouting also follows FF transections. F F transections did indeed lead to MF sprouting, which became apparent at 14 days and reached asymptotic levels at 28 days post-lesion. These results indicate a possible mechanism for the epileptiform activity s een following FF lesions and provide an additional example of the dive rse epileptogenic treatments that are accompanied by MF sprouting.