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

Abstract

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 (I8F-2DG) 18F-2-deoxyglucose, it is now possible to assess local glucose uptake in pmolil00 g tissueimin 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 I8F-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 1Oi20 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 10120 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,

EEG Alpha Rhythm and Glucose Metabolic Rate in the Thalamus in Schizophrenia

“…In the normal controls, there was the expected significant negative correlation (table 1) between absolute alpha power and GMR in the left occipital cortex, Brodmann's area 17, at leads O1 (r = -0.55) and Oz (r = -0.57), consistent with our earlier report [8]. In the same group, there were also significant positive correlations between normalized alpha power and GMR in the right lateral thalamus at leads O1 (r = 0.56), and Oz (r = 0.69), and between normalized alpha power and GMR in the left lateral thalamus at lead O1 (r = 0.67) (table 2).…”

“…The present finding of negative correlations between alpha power and GMR in the occipital cortices is consistent with our previous results [8] and with the results of previous studies [9,41]. In our study, we found that normal controls who had higher alpha amplitude had relatively lower occipital cortex metabolic rates.…”

“…Buchsbaum et al [8] earlier reported that normal individuals with relatively higher alpha amplitude had relatively lower occipital cortex metabolic rates, consistent with the interpretation of the alpha rhythm as a resting rhythm of the occipital cortex. Similar negative correlations between quantitative EEG measurements of alpha power and cortical perfusion measured by H 2 15 O-PET in normal subjects have been reported [9,10].…”

“…The underlying neurophysiological mechanisms of the negative correlations between alpha rhythm and occipital cortical metabolism are, like the described positive correlation between alpha and thalamic metabolism, still poorly understood. Although it has been proposed that the alpha rhythm represents a correlate of resting activity in the cortex [1,8,9], there are some substantial arguments against this hypothesis [2,3]. The alpha rhythm occurs only during wakefulness and not during sleep, and alpha waves may increase during some attentional tasks.…”

Electroencephalographic Characterization of Brain Dopaminergic Stimulation by Apomorphine in Healthy Volunteers

“…The beta increase over the centro-frontal scalp areas can be interpreted as an electrical activation of cortical brain structures [Yamamoto, 1989;Duchemin, 1983;Buchsbaum et al, 1982b] and its topography corresponds to the major mesocortical dopaminergic neuronal path-Luthringer/Rinaudo/Toussaint/Bailey/ Muller/Muzet/Macher way [Duchemin, 1983]. This is supported by results obtained in both animals and in humans.…”