New methods to determine the CNS effects of antigeriatric compounds: EEG topography and glucose use

Publisher Website
Google Scholar
Abstract
Buchsbaum, M.S., J. Cappelletti, R. Coppola, F. Regal, A. C. King, and D. P. van Kammen: New methods to determine the CNS effects of antigeriatric compounds: EEG topography and glucose use. Drug Dev. Res. 2:489–496, 1982.It has previously been possible to measure regional glucose use in the cerebral cortex in animals only with autoradiographic techniques. With the advent of position emission tomography (PET) using (18F‐2DG) 18F‐2‐deoxyglucose, it is now possible to assess local glucose uptake in μmol/100 g tissue/min in normal volunteers or patients. The PET technique is complex and costly and cannot be repeated frequently because of the radiation dosage. However, local glucose use is closely tied to cerebral blood flow, and studies have related blood flow to EEG frequency measures. In this study, we have simultaneously investigated local glucose metabolism using 18F‐2DG with PET and EEG frequency with 16‐lead topographic mapping in six normal controls. Subjects sat in an acoustically treated darkened room with eyes closed for 10 min prior to, and 30 min following injection of 3–5 mCi 18F‐2DG. Following uptake, seven to eight horizontal scans parallel to the canthomeatal line were made. EEG recordings are made beginning 1 min after injection of the isotope and continuing for 30 min with 12 standard 10/20 system points on the left hemisphere and midline, and 4 additional points between existing posterior leads. Ten‐second EEG epochs are edited for artifacts and then analyzed by fast Fourier transform techniques. Using a cross‐sectional whole‐head atlas, a standardized, approximately equal‐area two‐dimensional representation of a lateral view of the brain was developed and 10/20 system scalp coordinates were projected onto it. EEG power estimates are interpolated for all points on this brain map. Using digital techniques, a 1‐cm‐thick cortical strip is peeled off each PET, slice and conformed to the lateral brain view, and values between strips are interpolated. The result is two simultaneously obtained electrophysiologic and metabolic lateral views of brain function displayed in gray‐scale values represented by dot density. In some subjects with eyes closed, alpha power is high in low glucose‐use regions, such as the occiput. Temporal regions appear low both in glucose use and in most power bands. Parallels between alpha distribution and glucose use are illustrated.