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Biomedical subjects

R E Townsend

Publications and source records attributed to R E Townsend.

7 recordsLinked to original sources
PubMed1979

Relation of frequency-analyzed EEG to monitoring behavior.

Two experiments examined the relation of prestimulus electroencephalographic (EEG) frequency to choice RT. Based on previous studies, initial analysis was concerned with 3--7 c/sec activity. In well-rested subjects (Exp. 1), trial-by-trial analyses indicated large variations in prestimulus EEG activity which were unrelated to RT and large variations in RT which were unrelated to prestimulus EEG. In Exp. 2, subjects were deprived of sleep for 1 night and within-subject comparisons made between RT and EEG activity immediately preceding the 10 shortest and 10 longest RT trials, and 10 trials where the subject failed to respond. Significant univariate correlations were found, largely between RT and the frequencies in the 15--20 c/sec range of EEG activity and not in the 3--7 c/sec activity. A multiple regression analysis using up to 5 EEG frequencies indicated significant correlations of prestimulus EEG activity with RT; but with considerable subject-to-subject variability in the EEG frequencies contributing to the multiple R. The overall results suggest that there can be considerable variation in EEG activity which is unrelated to performance, except when the EEG fluctuations are secondary to changes in arousal which, in turn, effect performance.

Adolescent↗
PubMed1978

Species differences in the in vitro metabolic reduction of the amphetamine metabolite, 1-phenyl-2-propanone.

Marked differences were observed, in the ability of fortified 9000 g liver homogenate supernatants from three species to reduce 1-phenyl-2-propanone to the corresponding alcohol. This metabolic keto-reduction was negligible in homogenates from the rat and extensive in the rabbit; guinea-pig liver homogenates had intermediate ability. Metabolic oxidation of 1-phenyl-2-propanol was negligible in all three species. The amount of deamination of amphetamine and of N-n-propylamphetamine was approximately equal, in vitro, in rats and guinea-pigs but two to three times greater in liver homogenates from rabbits. Approximately three times more deaminated products were formed from the in vitro metabolism of N-n-propylamphetamine than from amphetamine metabolism by all three species.

Acetone↗
PubMed1978

Sleep, mood, and fatigue during a 14-day He-O2 open-sea saturation dive to 850 fsw with excursions to 950 fsw.

To obtain information on sleep, mood, and performance of divers and surface support personnel during deep dives in the open sea, 12 divers and 12 surface support personnel were monitored during a 14-day open-sea saturation dive using the U.S. Navy Deep Diving System, Mark 2, Mod O. Divers lived in the deck decompression chambers at 850 fsw equivalent and made 5 days of excursion wet dives to approximately 950 fsw via the Personnel Transfer Capsule. Electroencephalographic and self-report measures of sleep, and measures of mood, anxiety, and 4-choice reaction time performance were obtained during a predive base-line period and throughout the dive and decompression. Results suggested that, unless personnel are rotated, there are limitations to the practical duration of very deep open-sea saturation dives caused by the accumulation of sleep debt, fatigue, and loss of psychological vigor.

Affect↗
PubMed1975

Stabilization of alpha frequency by sinusoidally modulated light.

Two experiments demonstrate that a spontaneous electroencephalographic (EEG) rhythm, alpha, can be frequency-stabilized by sinusoidally modulated light (SML) but not by photic flash stimulation. It is suggested that this frequency stabilizing effect is not due to superimposition of an evoked response on the background EEG. Instead, SML might phase-lock the scalp-recorded alpha rhythm by influencing subcortical alpha generators within narrow limits set by the inherent resonant EEG frequency.

Adolescent↗