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Biomedical subjects

T C Floyd

Publications and source records attributed to T C Floyd.

26 records · Page 2Linked to original sources
PubMed1979

Flurazepam effects on sleep EEG. Visual, computer, and cycle analysis.

Analysis of sleep effects of flurazepam hydrochloride on four normal subjects confirmed that this drug substantially suppresses both REM and stage 4 sleep. Computer analysis disclosed that delta wave amplitude was greatly reduced by flurazepam. However, low density delta wave activity (ie, stage 2 sleep, which was increased in duration beyond the reduction in stage 4), permitted the number of delta waves and the time they occupied per night to remain at baseline levels. This finding suggests that sedative-hypnotics increase total sleep time by slowing the metabolic processes of sleep so that a longer sleep duration is required for the same biological effects. New observations on the induction times of REM and stage 4 effects are also presented. In general, the distortions in sleep EEG produced by flurazepam qualitatively resemble, but are quantitatively greater than, those produced by barbiturates in equivalent hypnotic doses.

Adult↗
PubMed1978

Effects of exercise on sleep.

We tested the hypothesis that EEG sleep stages 3 and 4 (slow-wave sleep, SWS) would be increased as a function of either acute of chronic exercise. Ten distance runners were matched with 10 nonrunners, and their sleep was recorded under both habitual (runners running and nonrunners not running, 3 night) and abruptly changed (runners not running and nonrunners running, 1 night) conditions. Analyses of both visually scored SWS and computer measures of delta activity during non-rapid eye-movement (NREM) sleep failed to support the SWS-exercise hypothesis. The runners showed a significantly higher proportion and a greater absolute amount of NREM sleep than the nonrunners. The runners showed less rapid eye-movement activity during sleep than the nonrunners under both experimental conditions, indicating a strong and unexpected effect of physical fitness on this measure. Modest afternoon exercise in nonrunners was associated with a strong trend toward elevated heart rate during sleep. Mood tests and personality profiles revealed few differences, either between groups or within groups, as a function of exercise.

Adult↗
PubMed1977

Flurazepam effects on slow-wave sleep: stage 4 suppressed but number of delta waves constant.

Repeated administration of flurazepam reduced stage 4 sleep (high delta-wave concentration) but produced a greater increase in stage 2 duration so that total sleep time was increased. Computer analysis revealed that the increased amount of stage 2 (low delta-wave concentration) sleep provided a number and duration of delta waves sufficient to offset the loss of delta activity in stage 4. However, the amplitude of the average delta wave was reduced. These results demonstrate the value of direct quantification of delta-wave activity, the variable that underlies visual classification of slow-wave sleep into stages 2 to 4. They also give rise to new hypotheses regarding the relative absence of side effects in spite of profound stage 4 suppression by flurazepam and the mechanisms by which total sleep time is increased by this drug.

Anti-Anxiety Agents↗
PubMedDate not supplied

Task-related EEG alpha asymmetry in schizophrenic patients prior to and after neuroleptic treatment.

EEG was recorded from bilateral frontal, central, temporal, and parietal leads (referenced to or transformed to a vertex reference) during cognitive activity in 13 normal controls, ten schizophrenics, and eight patients with affective disorders. All subjects were male and right-handed, and patients had been free of psychotropic medications for at least 2 weeks. A verbal (copying text) and spatial (copying shapes) task were matched for stimulus presentation and motor output. The number and rate of correct responses were recorded for each normal subject and 11 of the patients. As reported by others, normal subjects manifested a significant difference in alpha asymmetry between the tasks, reflecting relatively greater alpha suppression over the left hemisphere during the verbal task compared to the spatial task (P less than 0.05). This effect was not significant in either patient group. However, analysis of seven schizophrenics after neuroleptic treatment revealed robust effects of task on alpha asymmetry similar to that present in the normal control group (P less than 0.02). The results suggest that abnormal task-related brain lateralization may be present in untreated schizophrenic patients, but it is state dependent and does not reflect permanent patterns of brain organization.

Adult↗