Memory dysfunction following unilateral transection of the fornix: a hippocampal disconnection syndrome.

This study presents a case with a discrete nondischarging lesion of the left fornix that resulted in a marked anterograde memory deficit that was defined by the same material, modality and methodologically specific features characteristic of unilateral lesions of the hippocampus. Since the fornix is the major efferent pathway of the hippocampus to the mamillary bodies, septal nuclei and anterior thalamic nuclei, this patient could be considered to have a hippocampal disconnection syndrome.