摘要:

ABSTRACTTo establish the stages of brain processing in an auditory stimulus localization task, event‐related potentials (ERPs) were recorded from 24 normal subjects listening to brief white noise stimuli in a free‐field situation from front, back, left and right loudspeakers. The subject's task was to respond to ‘target’ stimuli from one designated speaker. Performance varied as a function of sound location, stimuli in the front/back dimension being more difficult to localize than those in the left/right. ERP results, based on averaged waveforms, difference waveforms and the factors derived from a principal components analysis, revealed a series of task related components. Some were relatively transient, others more sustained in character. One brain component showed task related amplitude changes with an onset as early as 15 msec. These changes were target specific for sounds in the easier left/right dimension only. Later components, such as the P300, also varied in amplitude between targets and non‐targets, but showed no significant amplitude or latency differences to target stimuli as a function of location, despite the significant performance di

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1983.tb00891.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1983.tb00892.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTThis study examined the eyeblink rate during non‐visual problem solving. A 2 × 2 × 2 factorial design compared eyeblink rates for easy and difficult problems, internally and externally directed attention, and numerical and alphabetical tasks. The major finding was a higher eyeblink rate for difficult problems. There was also a significant interaction between difficulty and the direction of attention; internally directed attention yielded higher blink rates only during the solution of easy problems. Range‐corrected data yielded the same pattern of results, butF‐values were consistently higher and accounted for a larger proportion of the v

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1983.tb00893.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1983.tb00894.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTThis study examined beat‐by‐beat relationships between blood pressure, the time interval from the ECG Q‐wave to the radial pulse wave (QRPI), and its two components, the cardiac pre‐ejection period (PEP) and aortic‐radial arterial pulse transit time (AR‐PTT). In 8 subjects, intra‐arterial systolic (SBP) and diastolic (DBP) blood pressure, QRPI, PEP, and AR‐PTT were measured during rest, mental arithmetic, cold pressor, and inhalation of amyl nitrite. Both PEP and AR‐PTT varied widely during each experimental condition indicating that QRPI change reflected both PEP and AR‐PTT change. AR‐PTT varied inversely with SBP and DBP; PEP sometimes varied directly and sometimes inversely with both SBP and DBP. QRPI varied inversely with both SBP and DBP with the magnitude of the correlation in a particular instance depending on the relationships for that instance between blood pressure and both PEP and AR‐PTT. Implications of the results for the use of either QRPI or AR‐PTT as indices of blood pres

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1983.tb00895.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTPsychophysiological tests of the Eysenck hypothesis that introverts are more arousal prone than extraverts have yielded somewhat mixed results. In an attempt to clarify and extend previous findings, the present study manipulated arousal level, using caffeine. Extreme groups of 48 extraverts and 48 introverts were used, and each subject was randomly assigned to a low, medium, or high dosage of caffeine or a placebo. Each subject heard a series of tones until criterion electrodermal habituation occurred. This was followed by dishabituation, overhabituation, and a further dishabituation procedure. Increasing caffeine dosages produced a linear increment in tonic levels in extraverts, but had little effect on SCL in introverts. Higher caffeine dosages also increased phasic response amplitudes in extraverts but decreased amplitudes in introverts. Although somewhat complex, results were partially supportive of the Eysenck hypothesis.

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1983.tb00896.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTThree groups of 10 normal subjects were trained with 13 maximal isometric contractions on each of 8 days. During 8 of the 13 trials, subject groups received either myoelectric feedback (MFB), or force feedback (FFB), or no feedback. Over the 8 training days all groups increased EMG activity, but no significant group differences in rate of acquisition were obtained. All groups made gains in force over the 8 days. Force feedback produced better acquisition than either MFB or control conditions. However, both MFB and FFB produced comparable and significant differences between feedback and no‐feedback trials within a session, highlighting the importance of control group designs in the assessment of biofeedback effects. Dissociation between surface EMG and force was shown not only in the training effects, but also in the difference between feedback and no‐feedback performance within a session. An analysis of covariance revealed that during feedback trials MFB produced some EMG facilitation which could not be attributed to increased force production. This effect may have been due to selective reinforcement by MFB of co‐contraction in the extraneous musculature, or of changes in motor unit firing patterns. These phenomena may also account for the relative failure of MFB to facilitate force acquisition. A one‐month follow‐up showed significant retention following similar losses of force in a

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1983.tb00897.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1983.tb00898.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTRelationships between pulse transit time (PTT) and intra‐arterial systolic (SBP), diastolic (DBP), and mean arterial blood pressure (MAP) were examined in 4 subjects under three conditions: rest, paced respiration, and mental arithmetic. PTT was measured from the EKG R‐wave to two peripheral pulses (brachial and radial) and from one pulse to the other. Three points on each pulse wave were used (peak, foot, slope) in the measurements, yielding nine different measures of PTT. The nine PTT measures were not consistently intercorrelated. PTTs initiated by the R‐wave were moderately correlated with SBP, but not with DBP or MAP. Brachial to radial PTTs were not correlated with any measures of BP. Relationships between PTT and BP also varied from subject to subject. The limited magnitude of the correlations and their inconsistency suggest caution in the simple substitution of PTT for beat‐to‐beat measu

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1983.tb00899.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTThe effects of exhaustive exercise on sleep were examined in 5 women and 4 men who performed an acute bout of submaximal exercise (50–70% Vo2max) to the point of volitional exhaustion. Significant changes were observed in the quantity and temporal distribution of slow‐wave sleep (SWS) on the exercise night. The duration of SWS prior to rapid eye movement (REM) sleep onset increased markedly, along with a moderate increase in stage 4 and total SWS. REM sleep variables were affected in the early portion of the night, with an increased latency to first REM onset and a decrease in the duration of the first REM period. Initial REM cycle length (from first to second REM period onset) decreased as well. The magnitude of the SWS increase prior to REM onset was sex‐related, averaging 24 min for women and 5.7 min for men. A correlation of .85 was observed between this increase and total caloric expenditure during exercise for the women. Cardiovascular measures indicated significant elevations of heart rate and cardiac output during sleep on the exercise night. Analysis of urine samples revealed a significant drop in nocturnal cortisol excretion rates after exercise.The results suggest that exhaustive exercise affects sleep primarily in the early portion of the night, inducing an increase in SWS pressure at the expense of REM

ISSN:0048-5772    

DOI:10.1111/j.1469-8986.1983.tb00900.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY