Ozerdem et al29 studied cortico-cortical connectivity by examining sensory-evoked coherence and event-related coherence values for the gamma frequency band during simple light stimulation and visual oddball paradigm in 20 euthymic drug-free BD patients and 20 sex- and age-matched healthy controls. The coherence values of the left and right intra-hemispheric electrode pairs (F3-T3, F3-TP7, F3-P3, F3-O1), and F4 -T4, F4-TP4, F4-P4, F4-O2, respectively) were compared between the groups. BD patients showed bilaterally diminished long-distance gamma coherence between frontal and temporal as well as between frontal and temporo-parietal regions compared with healthy controls. The reductions in gamma coherence between the electrode pairs were statistically significant.
