Functional connectivity networks are disrupted in left temporal lobe epilepsy.
OBJECTIVE
Functional connectivity maps the distributed network of brain regions fluctuating synchronously during a continuous brain state. This study sought to investigate whether patients with left temporal lobe epilepsy (TLE) differ from controls in their resting-state functional connectivity between typical language regions.


METHODS
We studied 17 patients with left TLE, together with eight healthy controls, using seeded functional connectivity. Seed regions were defined using the regions of maximal activation and deactivation during a language functional magnetic resonance imaging (fMRI) task in a separate cohort of 30 controls.


RESULTS
Language fMRI produced the expected activation pattern, which was not different between patients and controls. However, functional connectivity between language areas during rest was markedly different; whereas controls showed connectivity between each of the seed areas and the majority of the language areas, patients showed connectivity only with a few areas, particularly the seed area itself. This difference was significant in the direct comparison of patients and control connectivity maps.


CONCLUSIONS
We suggest that this reduced connectivity in left temporal lobe epilepsy may reflect a disturbance of the language network during resting state in patients and may be related to subtle language difficulties in this patient population.
Waites
Anthony B
AB
Brain Research Institute, Austin Health, Heidelberg West, Victoria, Australia.
Briellmann
Regula S
RS
Saling
Michael M
MM
Abbott
David F
DF
Jackson
Graeme D
GD
D000328:Adult; D001931:Brain Mapping; D004833:Epilepsy, Temporal Lobe / Q000473:pathology* / Q000503:physiopathology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007802:Language; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000098:blood supply / Q000473:pathology* / Q000503:physiopathology*; D010100:Oxygen / Q000097:blood
D010100:Oxygen