Effect of the 5-HT1A partial agonist buspirone on regional brain electrical activity in man: a functional neuroimaging study using low-resolution electromagnetic tomography (LORETA)

In a double-blind, placebo-controlled study, the effects of 20 mg buspirone - a 5-HT1A partial agonist - on regional electrical generators within the human brain were investigated utilizing three-dimensional EEG tomography. N ineteen-channel vigilance-controlled EEG recordings were carried out in 20 healthy subjects before and 1, 2, 4, 6 and 8 h after drug intake. Low-resol ution electromagnetic tomography (LORETA; Key Institute for Brain-Mind Rese arch, software: http://www.keyinst.unizh.ch) was computed from spectrally a nalyzed EEG data, and differences between drug- and placebo-induced changes were displayed as statistical parametric maps. Data were registered to the Talairach-Tournoux human brain atlas available as a digitized MRI (McConne ll Brain Imaging Centre: http://www.bic.mni.mcgill.ca). At the pharmacodyna mic peak (Ist hour), buspirone increased theta and decreased fast alpha and beta sources. Areas of theta increase were mainly the left temporo-occipit o-parietal and left prefrontal cortices, which is consistent with PET studi es on buspirone-induced decreases in regional cerebral blood flow and fenfl uramine-induced serotonin activation demonstrated by changes in regional ce rebral glucose metabolism. In later hours (8th hour) with lower buspirone p lasma levels, delta, theta, slow alpha and fast beta decreased, predominant ly in the prefrontal and anterior limbic lobe. Whereas the results of the I st hour speak for a slight CNS sedation (more in the sense of relaxation), those obtained in the 8th hour indicate activation. Thus, LORETA may provid e useful and direct information on drug-induced changes in central nervous system function in man. (C) 2000 Elsevier Science Ireland Ltd. All rights r eserved.