title: Temporal lobe interictal epileptic discharges affect cerebral activity in "default mode" brain regions.
abstract: A cerebral network comprising precuneus, medial frontal, and temporoparietal cortices is less active both during goal-directed behavior and states of reduced consciousness than during conscious rest. We tested the hypothesis that the interictal epileptic discharges affect activity in these brain regions in patients with temporal lobe epilepsy who have complex partial seizures. At the group level, using electroencephalography-correlated functional magnetic resonance imaging in 19 consecutive patients with focal epilepsy, we found common decreases of resting state activity in 9 patients with temporal lobe epilepsy (TLE) but not in 10 patients with extra-TLE. We infer that the functional consequences of TLE interictal epileptic discharges are different from those in extra-TLE and affect ongoing brain function. Activity increases were detected in the ipsilateral hippocampus in patients with TLE, and in subthalamic, bilateral superior temporal and medial frontal brain regions in patients with extra-TLE, possibly indicating effects of different interictal epileptic discharge propagation.
authors.affiliation: Department of Clinical and Experimental Epilepsy, Institute of Neurology, London, UK. helmut@laufs.com
authors.forename: Helmut
authors.initials: H
authors.lastname: Laufs
authors.forename: Khalid
authors.initials: K
authors.lastname: Hamandi
authors.forename: Afraim
authors.initials: A
authors.lastname: Salek-Haddadi
authors.forename: Andreas K
authors.initials: AK
authors.lastname: Kleinschmidt
authors.forename: John S
authors.initials: JS
authors.lastname: Duncan
authors.forename: Louis
authors.initials: L
authors.lastname: Lemieux
mesh_terms: D001303:Auditory Cortex / Q000503:physiopathology; D001931:Brain Mapping; D002560:Cerebrovascular Circulation / Q000502:physiology; D003937:Diagnosis, Differential; D004569:Electroencephalography; D004827:Epilepsy / Q000175:diagnosis / Q000503:physiopathology*; D017029:Epilepsy, Complex Partial / Q000175:diagnosis / Q000503:physiopathology; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis / Q000503:physiopathology*; D005071:Evoked Potentials / Q000502:physiology*; D007839:Functional Laterality / Q000502:physiology; D006624:Hippocampus / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D009415:Nerve Net / Q000503:physiopathology*; D011237:Predictive Value of Tests; D017397:Prefrontal Cortex / Q000503:physiopathology; D012680:Sensitivity and Specificity; D020531:Subthalamic Nucleus / Q000503:physiopathology; D013702:Temporal Lobe / Q000503:physiopathology*