Impaired self-referential processing in mesial temporal lobe epilepsy: A functional MRI study

Mesial temporal lobe epilepsy (mTLE) presents typical symptoms of cognitive impairments and mental disorders, which is presumed to be related to impairment of self-referential processing. This study aims to investigate the alterations of self-reference in mTLE using functional magnetic resonance imaging (fMRI). Fifty patients with unilateral mTLE (26 left- and 24 right-sided mTLE) were recruited in the present study. Traditional task paradigm of internally-cued condition vs. externally-cued condition was employed to induce self-referential activation. FMRI activation in each group of patients was compared with that of 30 healthy controls. Moreover, fMRI responses in the dorsal mesial prefrontal cortex were specifically addressed by correlating with behavioral data of reaction times and clinical data of epilepsy duration, respectively. Compared with the healthy controls, both two groups of patients showed decreased behavioral performance (reaction times) and decreased fMRI activation of self-reference in the anterior and posterior cortical midline structures. Moreover, fMRI activation was found to be negatively correlated with behavioral performance and epilepsy duration. The present findings implicate functional impairment of self-reference caused by epilepsy in mTLE. This study provided imaging evidence for functional impairments of self-referential processing and brain default-mode function in mTLE.