Pattern of memory impairment in two patients with septohippocampal disconnection

We describe two patients with lesions at different levels of the septo-hippocampal system. Both of them were selectively affected by anterograde amnesia, with a less severe retrograde amnesia. These data confirm that the integrity of the septo-hippocampal system is indispensable for the maintenance of normal memory and learning mechanisms and that the lesions along this fibre pathway, causing a functional and anatomic disconnection between the septal area (basal forebrain) and the medial temporal lobe structures, interfere with normal explicit memory functions.