P02-154 - Intracebral functional (LORETA) connectivity during attention to bodily and mental processes and resting

Objectives Attention is hypothesized to increase the brain's functional connectivity measured as EEG coherence between brain areas. Is this true for different types of attention compared to no-task resting? Methods In 25 healthy, meditation-naive, right-handed, male students 58-channel EEG was recorded during three conditions of 5 minutes each with closed eyes in randomized order: (1) resting [3 runs], (2) mental arithmetic [2 runs], and (3) breath counting, a meditation initiation technique [2 runs]. For the 8 EEG frequency bands, the artifacted EEG was recomputed into sLORETA intracerebral current densities. To avoid localization ambiguities, we computed EEG coherence between sLORETA areas. To avoid effects of volume conduction, we computed intracerebral `lagged coherence' connectivity between sLORETA current densities in 19 areas. Averaged resting runs were compared to those breath counting and arithmetic runs of which participants post-hoc reported that their concentration was best. Results Paired t-tests between conditions yielded differences of coherence at p Conclusions Attention to breath counting showed lowest, to arithmetic highest demands on intracerebral functional connectivity. Breath counting and mental arithmetic induce mental states whose inter-area connectivity differs in opposite directions from resting. The results do not support a global hypothesis of increased coherence during attention.