The Role of the Mammillary Bodies in Memory: A Case of Amnesia Following Bilateral Resection

Abstract

Background and Objectives: Craniopharyngioma (CP) patients typically show good neuropsychiatric outcome following tumor resection. We present the case of a 51-year old woman who sustained damage to white matter pathways during surgery resulting in a disconnection of the Papez circuit (loss of bilateral mammillary bodies, columns of the fomix and mammillothalamic tracts). Methods and Results: Neuropsychological evaluations were completed at 10 and 30 weeks post-operatively, and indicated both retrograde and severe anterograde amnesia, as well as persistent depression. At the second evaluation, most cognitive deficits had improved, but memory and mood deficits remained. Metamemory and priming remained intact. Conclusions: This case illustrates a profound neuropsychiatric morbidity associated with a surgery that is typically considered benign and confirms the well-known dissociation between explicit recollection of newly learned information and less conscious forms of learning and memory. This rare pathology provides further information regarding the role of the mammillary bodies in memory.