Patients with medial temporal lobe epilepsy based on left hippocampal sclerosis often show severe verbal memory deficits. Recent studies suggest that memory formation in these patients may be reallocated to the right hemisphere owing to left hippocampal pathology. To test this hypothesis, we used functional magnetic resonance imaging to examine encoding-related activity of verbal items in temporal lobe epilepsy patients with left hippocampal sclerosis and patients with idiopathic epilepsy as a control group. Results demonstrated that patients with idiopathic epilepsy showed more activation in both left and right hippocampi. The temporal lobe epilepsy group showed enhanced activation in left fusiform gyrus. We discuss these results in terms of different strategy use by the groups.
aHuman Cortical Physiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
bDepartment of Neurology II, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
Correspondence and requests for reprints to Dr Michael Schaefer, PhD, National Institute of Neurological Disorders and Stroke, Human Cortical Physiology Section, National Institutes of Health, Bldg. 10, Room 5N-234, Bethesda, MD 20892, USA
Tel: +1 301 40 29283; fax: +1 301 402 7050; e-mail: email@example.com
Sponsorship: M.S. was supported by the Deutsche Forschungsgemeinschaft (Scha105/1-3; SFB 6006); M.R. was supported by BMBF-grant 01GO0202 (CAI) and the Deutsche Forschungsgemeinschaft (SFB 6006).
Received 11 March 2006; accepted 5 April 2006