Effects of scopolamine on interhemispheric EEG coherence in healthy subjects: analysis during rest and photic stimulation.

The present study of coherence analysis, in 16 healthy male volunteers, aged 24-31 years, showed that the administration of 0.25 mg of scopolamine significantly reduced interhemispheric coherence in the delta and beta-1 bands in the resting state. Scopolamine also caused a significant increase both in EEG coherence during PS and in PS-related coherence reactivity in the beta band. In addition, this compound significantly reduced total WMS scores. These findings suggest that, in addition to causing cognitive impairments, central cholinergic dysfunction can alter interhemispheric functional connectivity under both nonstimulus and stimulus conditions.