2008 Brain Star Award Recipient - Ben Bowles
Recipient
Ben Bowles - Biosketch
Neurosciences
University of Western Ontario
Article
Impaired familiarity with preserved recollection after anterior temporal-lobe resection that spares the hippocampus. Bowles B, Crupi C, Mirsattari SM, Pigott SE, Parrent AG, Pruessner JC, Yonelinas AP, Köhler, S. Proc Natl Acad Sci U S A. 2007 October 9; 104(41): 16382–16387.
Significance of the paper
Our ability to recognize environmental stimuli and people we've met before is a critical skill for day-to-day life. This ability is important clinically, as it can be pathologically altered in patients with neurological disorders such as Alzheimer's disease (AD) and Capras Syndrome, who can loose their ability to recognize, close family members as familiar. It is agreed that there are two components to such recognition memory: a sense of perceived familiarity for the recognized person or object, and the experience of recollecting specific contextual details regarding the where and when of earlier encounters. Our article shows for the first time that the familiarity component of recognition memory can be selectively affected by focal brain damage in the temporal lobe. As such, this evidence points to a distinct neural substrate for the familiarity process that differs from the one for recollection.
Our conclusions are based on our neuropsychological investigation of a patient who received a rare form of brain surgery in the left anterior temporal lobe for the treatment of intractable epilepsy. The surgery was unique in that the neurosurgeon made a special effort to leave the hippocampus structurally intact. The hippocampus was not resected both in order to maintain the patient's excellent memory, and also because the origin of the epilepsy was pre-surgically located to be outside this structure. Importantly, this more selective surgery was still sufficient to alleviate all epileptic symptoms. Further, although it caused a change in the patient's experience of familiarity, it did not cause the more serious and debilitating memory impairments commonly observed in patients who receive surgery that resects the hippocampus. This case study therefore highlights the importance of this rare surgery for epilepsy treatment. This research was supported by a grant from CIHR to Dr. Stefan Köhler.