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Titolo:
SIMULATED MICROGRAVITY AND CORTICAL INHIBITION - A STUDY OF THE HEMODYNAMIC-BRAIN INTERACTION
Autore:
VAITL D; GRUPPE H; STARK R; POSSEL P;
Indirizzi:
DEPT CLIN & PHYSIOL PSYCHOL,OTTO BEHAGHEL STR 10 D-35394 GIESSEN GERMANY
Titolo Testata:
Biological psychology
fascicolo: 1-2, volume: 42, anno: 1996,
pagine: 87 - 103
SICI:
0301-0511(1996)42:1-2<87:SMACI->2.0.ZU;2-D
Fonte:
ISI
Lingua:
ENG
Soggetto:
CAROTID BARORECEPTORS; BED REST; RESPONSES; HUMANS;
Keywords:
MICRO-GAVITY; POSTURE; EEG; STARTLE RESPONSE; REACTION-TIME; CARDIOVASCULAR DECONDITIONING;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Physical, Chemical & Earth Sciences
Science Citation Index Expanded
Citazioni:
31
Recensione:
Indirizzi per estratti:
Citazione:
D. Vaitl et al., "SIMULATED MICROGRAVITY AND CORTICAL INHIBITION - A STUDY OF THE HEMODYNAMIC-BRAIN INTERACTION", Biological psychology, 42(1-2), 1996, pp. 87-103

Abstract

The present study was carried out to determine the inhibitory cortical processes induced by changes in hemodynamics. Previous experiments in humans conducted in our laboratory have shown that there is a close relationship between posture and delta and theta EEG activity. The most pronounced effects were obtained during the 6 degrees head-down tilt(HDT) position. In space medicine the HDT procedure is very frequently employed to simulate micro-gravity and to determine the neurohormonal counter-regulations evoked by the expansion of central volume. Twenty male subjects spent 23 h in bed in 6 degrees HDT and 23 h in 6 degrees HUT (head-up tilt) positions during which EEG (frontal, central, parietal, occipital), startle responses, and reaction-times were measured every 2 h (from 10:00 h till 20:00 h). The effects of cardiovasculardeconditioning (CD) regularly occurring after HDT were assessed by examining orthostatic tolerance and the physical work capacity (bicycle ergometry). As expected, 23 h HDT led to more pronounced CD than HUT. Spectral power analyses of EEG revealed increases in delta and theta frequency bands similar to those found during HDT in previous EEG studies. In addition, subjects responded more slowly (S1-S2 reaction-time task) during HDT as compared with HUT bedrest. The influence of HDT on startle response, however, was not in keeping with the initial hypothesis (i.e. dampening of reflex activity). The EEG data and the sensorimotor performance indicated that the body fluid shift towards the thoracic cavity induced by HDT resulted in signs of cortical inhibition. Inaddition to neural mechanisms, other processes must be postulated which are closely related to the counter-regulation evoked by the varyingbody positions.

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Documento generato il 12/08/20 alle ore 20:28:38