Skin Vasomotor Responses Research Articles

Sleep stage-related changes in sympathetic sudomotor and vasomotor skin responses in man

Objectives: The aim of the study was to evaluate the characteristics of the spontaneous and evoked sympathetic skin responses (SSR) during sleep and wakefulness in comparison with the skin vasomotor responses (SVR).Methods: Five healthy subjects underwent a night of videopolysomnographic recording. Spontaneous SSR were recorded via surface electrodes placed on the dorsal and ventral aspect of the hand while SVR were evaluated by means of an infrared photoelectric transducer placed on the index finger. SSR and SVR were evoked via electrical stimuli applied to the left supraorbital nerve.Results: Spontaneous SSR frequency was highest during stage 4 of NREM sleep and lowest during REM phases. On the contrary, spontaneous SVR frequency reached its lowest value during stage 4 and its highest value during stage 2 of NREM sleep, remaining at levels above waking values during REM. SSR could be elicited by stimuli inducing arousal during light sleep but it was absent during deep NREM and REM sleep. SVR could be evoked throughout NREM and REM sleep.Conclusions: Spontaneous SSR and SVR act differently during physiological modifications of vigilance. Evoked SSR is strictly dependent upon the state of vigilance, whereas evoked SVR shows no modifications during the different stages of the wake–sleep cycle.

Efferent projections from the preoptic area for thermoregulatory skin vasomotor response

Efferent projections from the preoptic area for thermoregulatory skin vasomotor response

Cold tolerance and metabolic heat production in male C57BL/6J mice at different times of day

Nine-month-old male C57BL/6J mice were subjected to three-hour cold stress tests (partial restraint at 6°C) at 9:00 a.m. or at 1:00 p.m. Tests were repeated three times at two-week intervals at the same time of day. Body temperature was measured by colonic thermoprobe, and metabolic heat production was measured by indirect calorimetry during each test. All mice showed habituation to repeated cold exposures (an improvement of cold tolerance across tests) due to an increase in metabolic heat production. The levels of metabolic heat production were similar during morning and afternoon testing; however, mice tested in the afternoon had consistently poorer cold tolerance, which indicated increased heat loss. Increased heat loss in mice of similar body weight and presumably similar body composition, suggests that there is less effective cold-induced skin vasoconstriction during the afternoon. We hypothesize that the compromised skin vasomotor response during the afternoon cold exposure results from competing effects of vasodilation due to local autoregulation stimulated by a circadian reduction of cardiac output during the sleep phase, and vasoconstriction due to the cold stress.

Stress hyperthermia: Physiological arguments that it is a fever

The theory that stress (or emotional) rise in central temperature (T c) in rats is a fever with an upward shift of the set-point temperature was tested with three experiments: 1) Measurement of tail skin temperature and T c during the emotional T c rise; 2) Investigation of the effect of ambient temperature on the emotional T c rise; and 3) The assessment of emotional T c rise during daytime and nighttime. Skin vasomotor responses helped the increase of T c toward a higher level and contributed to the regulation of central temperature at this new higher level. The cold environment did not diminish the emotional rise of central temperature as it would be expected in the case of a hyperthermia. However, at night emotional fever reached a higher level than during the daytime, suggesting that prostaglandin rise in T c is distinct from emotional or stress-induced hyperthermia. In conclusion, the experiments reported here confirm the hypothesis that the rise of T c induced by handling or disturbance of the rats is regulated, and is due to a shift of the set-point as occurs in fever.

Elicitation of subjective uncertainty during vasomotor and electrodermal discrimination classical conditioning.

ABSTRACTSubjective uncertainty was introduced during discrimination classical conditioning of the skin conductance and vasomotor responses. All 48 college student subjects were informed that one 7‐sec colored light would always be followed by a shock (CS+) while a 7‐sec light of another color would never be followed by a shock (CS−). After half of the conditioning trials, a novel stimulus (NS) was illuminated (a third color) and remained on. One group was previously informed about the NS while the other group was noninformed. Results of between trial verbal reports and postsession interviews indicated that noninformed subjects experienced more general uncertainty and more uncertainty regarding the CS‐US contingency on the postNS trials than did the informed group. On the trial pair following the NS onset, the short latency electrodermal response (1 to 4.5 sec) of the noninformed subjects increased while the informed subjects maintained a stable level of responding. Evaluation of later postNS trials revealed that the long latency response (4.6 to 7.9 sec) of the noninformed subjects decreased more than for the informed subjects. The decrease for the noninformed subjects was greatest to CS+. No group differences in vasomotor activity were elicited by NS onset. It was concluded that momentary increases in orienting and more sustained decreases in preparatory activity may accompany increases in subjective uncertainty.

The effect of task and stimulus variability on habituation of electrodermal and vasomotor reactions

The effects of reaction time (RT) task and stimulus variability upon the habituation of skin conductance responses (SCR) and vasomotor responses (VMR) were studied in two experiments. In Experiment 1, subjects who performed an RT response to stimulus onset or who received stimuli which varied in frequency required more trials to reach an SCR habituation criterion than subjects who did not perform the task or receive frequency variability. While the overall VMR magnitude was affected by RT task and frequency variability, no VMR habituation itself was observed. In Experiment 2, the effects of RT task to stimulus offset and stimulus-duration variability were investigated. RT task again produced retardation of SCR habituation. This indicated that the task effect was not simply due to contraction-elicited SCRs, since the task reactions occurred well after the onset-elicited SCRs. Stimulus-duration variability reduced the overall effect of task, and it was hypothesized that manipulations which tend to increase postonset SCR reactivity have a negative effect on the persistence of onset reactivity.

Interactions between local and reflex influences on human forearm skin blood flow

A three-part experiment was designed to examine interactions between local and reflex influences on forearm skin blood flow (SkBF). In part I locally increasing arm skin temperature (Tsk) to 42.5 degrees C was not associated with increases in underlying forearm muscle blood flow, esophageal temperature (Tes), or forearm blood flow in the contralateral cool arm. In part II whole-body Tsk was held at 38 or 40 degrees C and the surface temperature of one arm held at 38 or 42 degrees C for prolonged periods. SkBF in the heated arm rose rapidly with the elevation in body Tsk and arm Tsk continued to rise as Tes rose. SkBF in the arm kept at 32 degrees C paralleled rising Tes. In six studies, SkBF in the cool arm ultimately converged with SkBF in the heated arm. In eight other studies, heated arm SkBF maintained an offset above cool arm SkBF throughout the period of whole-body heating. In part III, local arm Tsk of 42.5 degrees C did not abolish skin vasoconstrictor response to lower body negative pressure. We conclude that local and reflex influences to skin interact so as to modify the degree but not the pattern of skin vasomotor response.

Peripheral skin temperature and vasomotor responses during hypnotic induction

Abstract The present study is a further investigation of the hypothesis proposed by Reid and Curtsinger (1968) that hypnosis involves changes in peripheral vasomotor responses and skin temperature. 20 male Ss, screened for hypnotic susceptibility, participated in 2 experimental sessions. Each S was hypnotized in 1 session and simply given instructions to relax in the other session. Peripheral skin temperature and pulse volume were continuously monitored through-out each session. The resulting data were analyzed to determine the effects of hypnosis on these physiological measures. Under both conditions, a tendency for increased skin temperature and increased vasodilation was found. It was concluded that neutral hypnosis does not involve changes in these measures which are appreciably different from the changes associated with relaxation.