Hippocampal functional connectivity reflects verbal episodic memory network integrity.
Using functional magnetic resonance imaging during a verbal memory task, we investigated correlations of signal fluctuations within the hippocampus and ipsilateral frontal as well as temporal areas in temporal lobe epilepsy patients. Declarative memory abilities were additionally examined before and after temporal lobe epilepsy surgery. A significant difference exists in functional connectivity between patients whose mnemonic functions deteriorated and those who remained stable or improved. Univariate analyses showed significantly higher preoperative coupling between the hippocampus and Brodmann area 22 for the group that decreased in verbal learning. We suggest greater coupling to reflect higher functional network integrity. Postoperatively reduced learning ability in patients with higher preoperative coupling underlines the importance of hippocampal interaction with cortical areas for successful memory formation.
Wagner
Kathrin
K
Epilepsy Center, University Hospital Freiburg, Freiburg, Germany. Kathrin.Wagner@uniklinik-freiburg.de
Frings
Lars
L
Halsband
Ulrike
U
Everts
Regula
R
Buller
Anne
A
Spreer
Joachim
J
Zentner
Josef
J
Schulze-Bonhage
Andreas
A
D000293:Adolescent; D000328:Adult; D001931:Brain Mapping; D003714:Denervation; D004833:Epilepsy, Temporal Lobe / Q000601:surgery; D005260:Female; D005625:Frontal Lobe / Q000502:physiology; D006624:Hippocampus / Q000293:injuries / Q000503:physiopathology*; D006801:Humans; D007802:Language; D007858:Learning / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008568:Memory / Q000502:physiology*; D008875:Middle Aged; D009415:Nerve Net / Q000293:injuries / Q000503:physiopathology*; D009434:Neural Pathways / Q000293:injuries / Q000503:physiopathology*; D009483:Neuropsychological Tests; D019635:Neurosurgical Procedures / Q000009:adverse effects; D013702:Temporal Lobe / Q000502:physiology; D014705:Verbal Behavior / Q000502:physiology*