Theta functional connectivity alterations related to executive control in refractory temporal lobe epilepsy

Using the attention network test (ANT) with simultaneous electroencephalography (EEG) recordings, this study investigated the neural mechanisms underlying executive control (EC) dysfunction in patients with temporal lobe refractory epilepsy.

Participants comprised three demographically matched groups (n = 20 each): refractory temporal lobe epilepsy (RE), drug-sensitive temporal lobe epilepsy (DSE), and healthy controls (Ctrl). Participants were instructed to perform the ANT while scalp EEG signals were simultaneously recorded. Theta-band functional connectivity was computed from EEG data acquired during ANT task execution.

The RE group exhibited significant impairment in EC performance. Theta-band functional connectivity strength in the whole-brain and frontal regions of the EC network was significantly reduced in both patient groups (RE/DSE) versus healthy controls. Notably, the RE group demonstrated reduced whole-brain and frontal theta connectivity within the EC network relative to the DSE group. Furthermore, frontal theta connectivity strength positively correlated with EC_effect in both Ctrl and DSE groups (r = -0.658, p = 0.002; r = -0.540, p = 0.014). In contrast, no significant association was observed between EC network theta connectivity and behavioral performance in the RE group (p > 0.05).

Patients with refractory epilepsy exhibited impaired EC behavioral performance, concomitant with reduced theta-band functional connectivity strength in frontal regions. This diminished frontal theta connectivity may underlie EC dysfunction in this patient population.