[Anesthetic mechanisms revealed by functional brain imaging].

Recent advancement in functional brain imaging techniques has revealed much of the global effects of general anesthetics on the human brain. General anesthetics preferentially suppress specific brain areas including the parietal association cortex and the thalamus, part of which appears to mirror the default mode network. Low-level sensory areas are relatively preserved and remain activated even under deep sedation by anesthetics. Functional connectivity analysis by resting-state functional magnetic resonance imaging has shown that general anesthetics moderately suppress functional connectivity of the default mode network. Midazolam-induced loss of consciousness is associated with remarkable suppression of cortico-cortical propagation of evoked currents. Overall, those results prompt us to hypothesize that general anesthetics induce loss of consciousness by disrupting the integrative properties of the cerebral cortex.