ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1989.tb02373.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1989.tb03126.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

ABSTRACTThe observation that aerobically fit persons react to physical load with a smaller sympathetic response than do less fit subjects suggests that their response to psychological stress might also be reduced. The evidence for this, however, is far from consistent. It was argued that this inconsistency might be due to the incomplete measurement of the response system involved. In the present experiment two groups, which differed strongly in maximal aerobic power, were compared with respect to their cardiovascular response to a laboratory stressor. In addition to the traditional heart rate and blood pressure measurements, pre‐ejection period, cardiac output, and peripheral resistance were assessed. Since only the part of the stress response that isnotaccounted for by metabolic needs might have pathological significance, the so‐called “additional’ responses were also measured. Fitness was shown to be associated with smaller sympathetic effects on both heart and vessels. The decrement in pre‐ejection period and the heart rate response were smaller in the high fit group. The total peripheral resistance and diastolic blood pressure responses pointed to a much stronger vascular reactivity in the low fit group. Unexpectedly cardiac output did not increase during stress. The strong heart rate response in the low fit group was compensated by a reduction in stroke volume, which probably originated in an increased peripheral resistance. The largest discrepancy between the effects of sympathetic activation during stress and exercise occurred in the vessels, as demonstrated by the large “additional’ response in total peripheral resistance during stress. The data point to the often neglected role of vascular processes in experiments of this kind. Furthermore, it seems necessary to take the effect of fitness into account when comparing subjects with respect to their cardiovascular st

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1989.tb03127.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1989.tb03128.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

ABSTRACTThree experiments examined the effects of stimulus novelty and significance on the skin conductance component of the orienting response. The test stimuli used in the different experiments involved either a neutral change in stimulation (i.e., adding or deleting components to the standard stimuli), or an introduction of a significant element to the standard stimulus. The serial position of the test stimulus was manipulated in all three experiments. In Experiment 1, nonsignificant test stimuli were introduced at the second, fourth, sixth, or eighth trial of the complex sequence of eight stimuli (i.e., a sequence comprised of varying standard stimuli). None of the test stimuli produced enhanced skin conductance responses under these conditions. Experiment 2 utilized the same design with only one difference: the test stimuli were presented following a simple stimulus sequence (i.e., repetition of a fixed standard stimulus). In this design enhanced skin conductance responses to the test stimuli were observed in almost all experimental conditions, with an advantage of a late over an early presentation of the test stimulus. Experiment 3 was designed to compare serial position effects of significant and neutral test stimuli. A serial position effect was obtained only for the neutral test stimuli, showing once again an advantage for late presentations. It was suggested that different mechanisms might underlie skin conductance responses to significant stimuli and to novel neutral stimuli.

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1989.tb03129.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

ABSTRACTThis study examined the interaction of race and parental history of hypertension on patterns of cardiovascular responses among women. Two stressors were used that produce different patterns of cardiovascular reactivity: mental arithmetic, primarily a beta‐adrenergic stimulus, and the cold face stimulus, which evokes alpha‐adrenergic (i.e. vascular) activity. Systolic and diastolic blood pressure, heart rate, forearm blood flow, and forearm vascular resistance were assessed before, during, and after arithmetic and cold face stimulus. Both tasks produced the expected patterns of cardiovascular adjustment, although no Black‐White differences occurred during arithmetic. However, Black subjects did show a slower recovery of diastolic blood pressure following arithmetic. The cold face stimulus produced significantly greater changes in systolic blood pressure in the Black than in the White women. Parental history of hypertension did not relate significantly to reactivity. The results provide limited support for the idea that Black females exhibit a greater pressor response than White females to a stimulus that produces primarily vascular rather than cardiac changes. These findings are discussed in relation to previous findings with males and with respect to their implications for the role of reactivity in Black‐White differences in hypertension pre

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1989.tb03130.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1989.tb03131.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

ABSTRACTGroups of schizophrenics and normal controls were exposed to different series of tones of constant (80dB) and variable intensity (60, 80, and 100 dB). Measurements included bilateral skin conductance, finger pulse volume, and heart rate. Both groups were split on the common median in skin conductance response to constant intensity tones to form matched patient and control groups of low and high responsivity. The low and high responsive schizophrenic groups were more clearly separated than the two control groups in rate of spontaneous skin conductance fluctuations, skin conductance magnitudes, and skin conductance levels, primarily because of generalized hyperactivity in high responsive patients. This pattern was clearest for the most intense tone and left hand recordings. High responsive schizophrenics also showed larger response amplitudes, shorter rise and recovery times, and a smaller ratio of elicited to spontaneous responses, than high responsive controls. Finger pulse volume responses recorded from the left hand were smaller in the patient groups, whereas patients and controls did not differ in right hand recordings. High skin conductance responsive subjects showed more heart rate deceleration than low responsive subjects, and schizophrenics had more decelerative responses than controls.

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1989.tb03132.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

ABSTRACTThe stability of physiological activity in the distal colon was investigated by recording 5–6 hours in each of 6 healthy adults. Contractions and myoelectric slow waves were recorded from the sigmoid colon (25–30 cm from the skin surface) and rectum (10–15 cm), and pressure waves were recorded from the proximal small intestine. The activity index (sum of areas of all waves divided by recording time) varied by 200% to 800% across 4‐min samples for all motility and myoelectric slow wave recordings. Spectral analysis indicated that contractile activity waxed and waned in a cycle with a period of 40–55 min in the colon and 64–80 min in the small intestine. Myoelectric slow wave activity in the colon cycled with a period of 30–40 min. Contractile activity in the sigmoid colon was correlated with similar activity in the rectum, but myoelectric slow wave activity in the colon was not correlated with myoelectric slow waves in the rectum. The frequency composition of contractions and slow waves was unsta

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1989.tb03133.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

ABSTRACTAutonomic response measures are well suited for the study of preparation because they allow the analysis of covert aspects of performance. This is illustrated by an experiment in which task‐evoked cardiac and pupillary responses were compared during a disjunctive (Go/No Go) reaction task. The motoric demands of the task were varied by manipulating foreperiod length (4 and 8 s) and probability of response (25%, 50%, and 75%). Reaction time increased with foreperiod length and decreased with probability of response. The depth of anticipatory heart rate deceleration was affected only by foreperiod length. Analysis of the beats during, and directly preceding and following the imperative stimulus revealed that interbeat intervals increased with probability of responding and foreperiod duration. The effect of stimulus timing relative to the R‐wave of the ECG was also analyzed. Early occurring stimuli prolonged the cycle of their occurrence more than late occurring stimuli. The cycle time effect was somewhat more pronounced for No Go stimuli than for Go stimuli. The subsequent cycle was shorter for early occurring stimuli compared to late stimuli. This effect was stronger for Go compared to No Go trials. Both Go and No Go reactions elicited significant pupil dilations. The No Go dilation peaked earlier than the Go dilation and its amplitude was smaller. Probability of responding affected the latency of the No Go dilation but not that of the Go dilation. The current results justify an interpretation of preparation in terms of a timing mechanism (indexed by heart rate deceleration during the foreperiod) and a mechanism allocating processing resources to stimulus encoding (indexed by cardiac slowing just prior to stimulus occurrence) and response preparation (indexed by continued cardiac deceleration and pupillary dilati

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1989.tb03134.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY