MRI-constrained spectral imaging of benzodiazepine modulation of spontaneous neuromagnetic activity in human cortex.
Spontaneous electromagnetic brain rhythms have been widely used in human neuropharmacology, but their applicability is complicated by the difficulties to localize their origins in the human cortex. Here, we used a novel multi-modal non-invasive imaging approach to localize lorazepam (30 microg/kg i.v.) modulation of cortical generators of spontaneous brain rhythms. Eight healthy subjects were measured with 306-channel magnetoencephalography (MEG) in a double-blind, randomized, placebo-controlled (saline), crossover design. For anatomically realistic source modeling, wavelet-transformed MEG data were combined with high-resolution MRI to constrain the current locations to the cortical mantle, after which individual data were co-registered to surface-based coordinate system for the calculation of group statistical parametric maps of drug effects. The distributed MRI-constrained MEG source estimates demonstrated decreased alpha (10 Hz) activity in and around the parieto-occipital sulcus and in the calcarine sulcus of the occipital lobe, following from increased GABA(A)-inhibition by lorazepam. Anatomically constrained spectral imaging displays the cortical loci of drug effects on oscillatory brain activity, providing a novel tool for human pharmacological neuroimaging.
Ahveninen
Jyrki
J
Massachusetts General Hospital/Massachusetts Institute of Technology/Harvard Medical School-Athinoula A. Martinos Center for Biomedical Imaging, CNY149 13th Street, Charlestown, MA 02129, USA. jyrki@nmr.mgh.harvard.edu
Lin
Fa-Hsuan
FH
Kivisaari
Reetta
R
Autti
Taina
T
Hämäläinen
Matti
M
Stufflebeam
Steven
S
Belliveau
John W
JW
Kähkönen
Seppo
S
D000328:Adult; D002540:Cerebral Cortex / Q000187:drug effects* / Q000502:physiology*; D004311:Double-Blind Method; D005260:Female; D018757:GABA Modulators / Q000494:pharmacology*; D006801:Humans; D008140:Lorazepam / Q000494:pharmacology*; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male
D018757:GABA Modulators; D008140:Lorazepam