Showing papers in "Psychophysiology in 1976"

The Cardiovascular-Behavioral Interaction—As It Appears Today

Abstract: Research is reviewed concerning the interrelationships among cardiodynamics, blood pressure control mechanisms, somatic activity, and the stimulus parameter of active vs passive coping. Emerging evidence suggests that with passive coping such as classical aversive conditioning, the heart is more under vagal control which is directionally linked with somatic activity, while blood pressure is more dominated by vascular processes. With active coping such as shock avoidance, the heart is under greater sympathetic control which is directionally independent of concomitant somatic activity, while cardiac influences on blood pressure become more dominant. Several current psycho physiological issues are discussed including the possible significance of these effects for cardiovascular disease processes.

Pulse Wave Velocity as a Measure of Blood Pressure Change

Abstract: The use of arterial pulse wave velocity (PWV) as a continuous measure of blood pressure changes is outlined. Theoretical considerations indicate that changes in PWV reflect changes in blood pressure, and an experiment was carried out to assess this relationship. PWV along an arm artery was monitored in 26 subjects at a time when the arterial distending pressure of the limb was altered over a wide range by means of externally applied positive and negative pressures. The results show that changes in PWV reliably follow changes in blood pressure. This method can be considered suitable for studies requiring changes rather than absolute values of blood pressure.

Auditory evoked potentials to unpredictable shifts in pitch.

Abstract: Auditory evoked potentials (EPs) were recorded from subjects presented with a regular series of tone pips at one of three rates (1/sec, 2/sec, or 4/sec). Occasionally one of the pips was 5%, 25%, or 100% (an octave) different in pitch from the repetitive background pips. These “mismatch” tones occurred at random with a mean interval of 12 sec (range 1–24 sec) for all of the repetition rates. This determined an average sequential probability = 0.083, 0.042, 0.021 that a tone would be a mismatch. On different runs, subjects either responded with a button press each time they heard a mismatch or they read a book. The amplitude of a large negative component (N2 at 154 msec) evoked after mismatch tones was unrelated to degree of mismatch but was larger to all the mismatch tones than to the background pip. Instructions to attend did not affect N2. A subsequent positive peak at 277 msec (P3), recorded during reading, did increase in amplitude with increasing mismatch, as did a P3 at 330 msec recorded during responding. Sequential probability had no main effect on N2 or P3. This lack of an effect on P3 suggests that the well-known influence of stimulus uncertainty on P3 may be determined by the temporal rather than sequential uncertainty of events, or that our range of probabilities was too narrow to obtain the effect.

The role of awareness in human differential autonomic classical conditioning: the necessary-gate hypothesis.

Abstract: A “necessary-gate” hypothesis is proposed regarding the relationship between awareness of the CS-UCS relationship and autonomic classical conditioning. The hypothesis is that awareness is a necessary but not sufficient condition, and a gate but not analog condition, for human differential autonomic classical conditioning. Evidence in support of the hypothesis is reviewed and directions for future research and theory development are suggested.

Pulse Wave Velocity and Blood Pressure Change: Calibration and Applications

Abstract: An adaptation of the technique for measuring pulse wave velocity is described in which the interval between the R wave of the ECG and the radial pressure pulse is monitored. The resulting transit time (TT) is suitable for use as an indirect measure of blood pressure change. The reliability of the measure was assessed in 5 subjects who volunteered for arterial cannulation on 2 occasions. Simultaneous recordings of intra-arterial pressure and TT were taken during a variety of maneouvres, including mental arithmetic, isometric exercise, and amyl nitrite inhalation. The dependence of changes in TT on arterial pressure was confirmed for all procedures except amyl nitrite inhalation. Linear correlations between TT and mean arterial pressure were high, varying between −.913 and −.98. The regression coefficients were reproducible and similar in all individuals. The reasons for the anomalous amyl nitrite response are discussed, together with the limits of application of the measure.

Effects of Exercise, Bedrest and Napping on Performance Decrement During 40 Hours

Abstract: : Young male Naval volunteers were denied normal nocturnal sleep and maintained on a 60-min treatment-160-min testing schedule for 40 consecutive hours Ten subjects bicycled, 20 subjects controlled EEG activity during bedrest, and 10 subjects napped Eight measures of addition, auditory vigilance, mood, and oral temperature were obtained The Bedrest group showed significant impairment on all eight measures, and thus, gave no support to the forced rest theory of sleep function The exercise group was worse than the Nap and Bedrest groups for all measures In spite of fragmented, reduced sleep (about 37 hours per 24 hours), the Nap group had no impairment on six of the measures The results suggest that exercise increases the impairment due to sleep loss, and naps reduce or remove this impairment

Sensation seeking, trait, and state anxiety, and the electrodermal orienting response.

Abstract: The relationship between sensation seeking and the orienting reflex (OR) using skin conductance change is investigated in two experiments. In Experiment I, high sensation seekers gave a greater initial OR In novel visual stimuli while not differing in habituation on subsequent trials. In Experiment II. the paradigm was extended to include auditory as well as visual stimuli. Again, high sensation seekers were found to be more arousable with respect to initial ORs while not differing in habituation rates. The results suggest that sensation seekers may be characterized as having strong excitatory CNS processes. In Experiment II, anxiety (trait and state) was also related to the OR. There were no effects due to trait anxiety but state anxiety did yield significant differences. The more highly anxious (state) subjects had weaker initial ORs than lows in both novel tones, but not to repeated tones. The findings with state anxiety are consistent with findings by others using anxiety neurotics as subjects.

Physiological assessment of sexual arousal in women.

Abstract: The purpose of this investigation was to validate the use of vaginal photoplethysmography along with six other physiological measures for the assessment of sexual arousal in women. Six women in counterbalanced order were presented control, dysphoric, and sexually arousing videotapes. Subjective ratings revealed that subjects experienced moderate levels of sexual and anxiety arousal during the videotapes, and comprehension quizzing at the end of the experiment showed that subjects attended to the content. Heart rate, heart rate variability, and skin conductance response failed to discriminate between any of the videotapes. In order from highest to lowest sensitivity, vaginal blood volume, skin conductance, systolic and diastolic blood pressure, and forehead temperature showed significant increases during the erotic videotape. Though sensitive, skin conductance appeared to he unreliable. Areas for further research were identified.

The effects of temporal and event uncertainty in determining the waveforms of the auditory event related potential (ERP).

Abstract: In each of two experimental conditions, subjects were presented with a series of tones; one of two tones (1500 Hz or 1000 Hz) was presented on each trial with a probability respectively of .10 or .90. The subjects counted the rare (p=.10) tones; such counted rare tones are normally associated with a large P300 component. The two conditions differed in that in one the tunes were triggered by the subject's button press; in the other the tones were triggered by computer. Schafer and Marcus (1973) reported that all the components of event-related potentials (ERPs) elicited by self-triggered tones were substantially smaller than those elicited by machine-triggered stimuli. Our paradigm allowed a detailed assessment of the effects of self-stimulation on specific ERP components as well as the interaction of temporal with event uncertainty. Data were analyzed using a Principal Components technique. Both temporal and event uncertainty appeared to augment a negative component of the ERP with approximately 140 msec latency. Such effects, however, were confounded by the presence of slow negative potentials preceding the button press in the self-stimulation conditions. As expected, the P300 component was largest for the ERPs elicited by the rare tones. Temporal uncertainty diminished the amplitude of P300 at central electrode sites. A large slow wave was present following P300; its anterior-posterior distribution was altered by mode of stimulus presentation. It appears that temporal and event uncertainty have distinct effects upon the morphology and distribution of KRP components.

Digital Temperature Autoregulation and Associated Cardiovascular Changes

Abstract: Two studies were designed to explore the extent to which individuals can learn to control their digital skin temperature and how such learning might be associated with changes in cardiovascular functioning. In the first experiment, 8 male and 8 female subjects were assigned to two experimental conditions in which either increases or decreases in digital skin temperature were rewarded. Subjects were given 2 baseline days and either 5 or 9 days of training. Analysis of the temperature data indicated that the differences between conditions were due to changes primarily in the decrease direction. All changes were bilateral. Analysis of heart rate revealed a sex difference in the cardiac response to voluntary vasodilation. Data from two plethysmographic measures are also presented. In the second experiment, it was demonstrated that lowering the ambient temperature decreased the ability of 8 subjects to voluntarily vasodilate.

Patterns of cerebral lateralization during cardiac biofeedback versus the self-regulation of emotion: sex differences.

Abstract: The purpose of the present study was twofold: (1) to obtain information on central mechanisms underlying cardiac self-regulation by comparing changes in cerebral asymmetry during self-control of heart rate with changes observed during the production of affective imagery; and (2) to explore sex differences in hemispheric function during performance of these two tasks. Heart rate (HR) and bilateral parietal EEG filtered for alpha were recorded from 20 right-handed males and females during two discrete experimental phases: cardiac control and image self-generation. HR showed significant effects between up versus down in prefeedback and feedback, and between anger versus relaxing imagery in the image phase. The EEG data indicated similar patterns of hemispheric asymmetry in both sexes during prefeedback. However, with the introduction of feedback, females shifted to greater relative right hemisphere activation comparable to what they show when specifically instructed to think emotional thoughts; males showed little differentiation between conditions. These data indicate that the Self-regulation of HR with biofeedback in males and females may be accomplished by the utilization of strategies involving different underlying patterns of neuropsychological processes.

The use of time lapse video recording of sleep-wake behavior in human infants.

Abstract: The present study describes the use of time lapse video recording or sleep-wake states in human infants. Polygraphic studies were carried out simultaneously to evaluate validity. Six normal, full-term infants were each recorded twice: first at 2 weeks and again at K weeks of age. Behavioral and physiologic states were scored from the video and polygraphic records, respectively, according to standard criteria. Interrater reliability for the video tapes was .92. In comparing the polygraphically determined states with the video scoring, a significant overall product-moment correlation of .79 was obtained for all states and ages. Similarly, the individual state correlations at both ages were statistically significant between the systems. Wakefulness was the most highly correlated state. Active-REM sleep was more highly correlated in the younger age group, while quiet-NRKM was more highly correlated in the older age group.

Blood pressure and heart rate changes accompanying classical eyeblink conditioning in the rabbit (Oryctolagus cuniculus).

Abstract: In two experiments employing 38 rabbits differential classical conditioning of heart rate, blood pressure, and corneoretinal potential (CRP) response were examined using l-sec and 4-sec interstimulus intervals ISI respectively. The conditioned response consisted of HK decelerations and DP depressor responses early in conditioning. However, many, but not all, animals revealed pressor responses and HR accelerations after the CRP discrimination was acquired. Significant correlations were also obtained between BP pressor responses, HR accelerations, and the frequency of CRP CRs. These results were discussed within the context of the orienting and defense reflexes.

Evoked Potentials in Hyperkinetic and Normal Children Under Certainty and Uncertainty: A Placebo and Methylphenidate Study

Abstract: Differences between hyperkinetic children and normal children and the effects of methylphenidate on hyperkinetic children were investigated under conditions of differential attentional demands. Auditory average evoked potentials were recorded from vertex using a single/double click guessing paradigm under conditions of certainty and uncertainty. Under conditions of certainty (low attention), in which the subject was told the identity of each stimulus in advance, few significant group differences were found. Under conditions of uncertainty (high attention), in which the subject was asked to guess which stimulus would be presented, large group differences were found. In response to the second click the P200 component was found to be smaller and the N250 component was larger in hyperkinetic children than in normal children. Treatment with methylphenidate “normalized” the evoked potentials of the hyperkinetic children making them more like those of normal children. The findings are believed: 1) to reflect the deficit in attention observed behaviorally in hyperkinetic children, 2) to support a model of hypoarousal in hyperkinetic children, and 3) to reflect the behavioral “normalization” observed in hyperkinetic children treated with melhylphenidate.

Effects of stimulus probability and task-relevance on event-related potentials

Abstract: Stimuli were delivered to 12 subjects in a sequence that included regularly occurring standard tone pips, random warning tone pips, and random while noise bursts. Half the noise bursts were preceded by warning tones (high probability), and half were not (low probability). There were four runs, each having one of two noise burst intensities, and each having the warning tone and noise bursts either both task-relevant to a reaction time task or both task irrelevant. Event-related potentials (ERPs) were obtained by signal averaging in F2, C2, P2 and eye leads. The P3 to the warning tone was largest in P, and was not affected by task relevance. CNVs preceded all the high probability noise bursts. These CNVs had an amplitude of 5μV even when the bursts were task irrelevant. Low probability noise bursts elicited larger P3s in all leads for the task-irrelevant condition, but only in Pz for the task-relevant conditions. In Cz, the amplitudes of NI. P2, and P3 to the high probability. task-relevant noise bursts correlated with the amplitude of the preceding CNV.

Delayed habituation of the electrodermal orienting response as a function of increased level of arousal.

Abstract: Level of arousal was manipulated by having subjects perform arithmetic tasks during a habituation procedure, which consisted of 55 presentations or a 1000 Hz 80 dB tone For one group a threat of shock was added to the task performance in order to include aspects of stress in the arousal manipulation These two groups were compared with a group who heard the same stimuli but were simply instructed to relax The three groups differed in level of arousal according to KEG signs of drowsiness, skin conductance level, and frequency of spontaneous skin conductance responses, All three groups differed from each other in number of trials to habituation criterion for skin conductance responses to stimuli Since the delay of habituation was seen tin- both the Task group and the Shock-threat group, it was concluded that the effect was not bound to aspects of stress but was a general effect of increased arousal For vasomotor responses an analysis in terms of habituation was difficult to apply because the two high arousal groups were very unresponsive from the beginning

The Effects of Presleep Activity on All‐Night Sleep

Abstract: The effects of different presleep activities on all-night sleep were assessed. Nine young adult males engaged in brief periods of progressive relaxation (Relaxation), light dynamic exercise (Exercise), or a boring monotonous vigilance task (Vigilance) immediately before bed on consecutive nights. Standard electrophysiological data were recorded during the 7.5 hrs of sleep. The latency of sleep onset was shortest after Relaxation and longest after Exercise. Presleep heart rate and electromyograph levels were not related to sleep onset. Sleep stages were not differentiated by condition and no sleep parameter differed from normative data. The results suggest that it is possible to alter sleep latency by manipulating presleep behavior without disrupting the normal steep pattern.

Habituation and the structure of the electrodermal system.

Abstract: The intercorrelatons among fifteen common SRR variables were investigated on two samples of male subjects in a standard habituation paradigm. The first group (N = 212) was made up of 149 prisoners and 63 controls (mean age = 28yrs) while the second group (N =84) were all twins (mean age=25 yrs). All subject received 21 auditory stimuli at an ISI of 33 sec. Each stimulus was sinusoidal, at 1000 Hz. of 1 see duration and at 95 (IB ire 20 N/cm2). The fifteen SRR measures taken from each subject included mean and change scores for basal conductance, response amplitude, spontaneous fluctuation frequency, number of responses, and onset, peak and half-recovery latencies. The variables were Intel-correlated and factor analyzed. The.05 rejection region was adopted in all statistical tests. A fun h simple structure for the variables was demonstrated. Hit' results emphasized the importance of a large general reactivity component in must of these variables. Within-subject correlations were calculated and found to be different from across-subject correlations. It is suggested that under constant stimulus conditions subjects display different but individually topical SCR shapes which reduce in size during habituation.

Heart Rate and Respiratory Responses as a Function of Task Difficulty: The Use of Discriminant Analysis in the Selection of Psychologically Sensitive Physiological Responses

Abstract: The relationship between physiological response patterns.and task difficulty was investigated by evaluating heart rate and respiratory responses during a choice reaction lime tusk with three levels of task difficulty. The data fit a two-component model or attention containing reactive and sustained responses. There were two reactive responses: An immediate deceleration which was independent of task manipulation; and a short latency response, monotonically paralleling task difficulty, which was characterized by acceleration and an increase in heart rate variability. The sustained component exhibited task dependent deceleration and u generalized reduction in heart rate variability and respiration amplitude variability. A stepwise discriminant analysis was performed on the task conditions using physiological responses to determine responses sensitive to task demands. Physiological response patterns were monotonically ordered as a function of task difficulty, suggesting that this technique may have advantages for determining physiological responses most sensitive to psychological manipulation.

Averaged evoked potential predictors of clinical improvement in hyperactive children treated with methylphenidate: an initial study and replication.

Abstract: In two experiments certain measures of the visual evoked potential (VEP) discriminated between hyperactive children who were subsequently judged by their pediatrician to have shown significant improvement (responders) with methylphenidate (Ritalin) as compared to children who showed a poor or marginal response to this drug. The principal findings were: 1) With Ritalin, EP variability increased when responders went from a task requiring active attention (ATT) to one requiring passive observing (PAS). In contrast, EP variability decreased in nonresponders when they went from ATT to PAS. 2) The amplitude of the M40-P190 component in the ATT condition increased from placebo to Ritalin for the responders. It was suggested that the variability measure primarily reflects an abnormalizing effect of Ritalin on the nonresponder while the N140-P190 component represents an apparent deficit in responders that is normalized by Ritalin.

An evaluation of finger pulse volume as a psychophysiological measure of anxiety.

Abstract: The present experiment explored the utility of finger pulse volume (FPV) as a measure of anxiety. Subjects were exposed to either a threatening or nonthreatening situation, and indices of physiological arousal (pulse rate (PR) and FPV) and self-report of anxiety (Affect Adjective Checklist (AACL)) were collected. Results indicated that FPV was responsive to changes in experimentally induced anxiety and significantly correlated with PR and AACL, although the strength of these relationships was not substantial. Relevance for psychophysiological theory and the clinical observation of anxiety is discussed.

Instrumental Control of Peripheral Vasomotor Responses in Children

Abstract: In two experiments children acquired instrumental control over skin temperature with the aid visual feedback. In Experiment 1,3 out of 4 children learned to control the temperature difference their two hands. In Experiment 2. one of these children acquired significant control of the difference between two fingers of one hand. Such highly specific responses apparently reflect direct instrumental modification of the vasomotor system since generalized effects due to muscular tension or respiration could he ruled out.

Paced respiration as a technique for the modification of autonomic response to stress.

Abstract: This study was designed to test the efficacy of a paced respiration procedure in reducing subjects' reactions to real and anticipated aversive events. The main hypothesis was that subjects who were taught how to pace their respiration at a slower than normal rate in accordance with a specified signal would show decreased autonomic responsiveness to an electric shock and its anticipation. Three groups of 13 subjects were employed. A Respiration Control group was compared with a group which received all the same stimuli but were instructed merely to pay attention to them without any respiration instructions (Attention Control group) and with a control group for whom the stimuli were or no significance. Results for electrodermal measurement, but not for cardiac measurement, indicated that the learning of a short series of breathing exercises can have significant facilitative effects on reducing autonomic responsivity to a stressful stimulus.

Blood pressure control: a comparison of feedback and instructions using pulse wave velocity measurements.

Abstract: A comparison was made between blood pressure changes with exteroceptive feedback and simple instructions. Twenty subjects were instructed either to raise or lower pressure for four sessions, while a further 20 were allowed to view an analogue visual display of mean arterial pressure. Pressure changes were continuously monitored with the pulse wave velocity method. When changes were analyzed from the initial baseline, both groups showed divergence between Increase and Decrease over trials, but feedback enhanced control in Increase only. On assessment from the running baseline, feedback control was superior in both direction conditions. This difference may In due to interaction between running baseline changes and experimental conditions. Control by feedback groups deteriorated when feedback was withdrawn. Modifications were accompanied by alterations in heart rate, respiratory activity and movement, although the association was of a gross nature only, being more prominent in increase conditions.

Learning to Control Heart Rate: Effects of Varying Incentive and Criterion of Success on Task Performance

Abstract: The effects of motivational variables on learned heart rate speeding and slowing were investigated. Undergraduate volunteers were randomly assigned to two groups which received feedback tasks differing in difficulty, i.e., a median target display (50% of all heart intervals would be successful based on no-feedback performance) and a quartile target (25% predicted success), Equal subgroups received either a monetary reward for successful performance or received no supplementary incentive. The results indicated that directional changes in heart rate could be achieved with simple instructions, and that heart rate control performance was generally superior under incentive conditions. Speeding showed overall improvement over feedback sessions, and over trials for the median target group. Slowing performance showed no general improvement over sessions and no effects of target. The effects of incentives on heart rate slowing were strongest on trial periods when subjects were under instructions to reduce heart rate, but no feedback display was presented. The results are interpreted within a skills learning conception of cardiac rate control training.

Daytime visual load and the effects upon human sleep.

Abstract: The importance of vision to man was used as a basis for a possible link between vision and sleep. A physiological approach to the human visual system identified several factors which might produce a visual load. Five subjects were exposed to high and low levels of visual load on two different occasions. Exercise and noise were controlled. Sleep EEGs were taken for 3 baseline nights and for 2 nights following each condition. The only significant changes were for SWS stages, which increased after the high load condition. These increases were particularly prominent on the second night. There were no significant changes fallowing the low condition. On all nights RKM remained constant: this was contrary to the cognitive theories of REM. Although the findings indicate that visual load can affect SWS. this interpretation is qualified.

Auditory analgesia: somatosensory evoked response and subjective pain rating.

Abstract: Subjective rating responses and averaged evoked responses (AERs) to shock stimuli of varying intensity were recorded in 20 subjects to examine the possible analgesic effects of sound stimulation (music) and suggested analgesia. Subjects (10 men, 10 women, ages 19–31) were divided into two groups of 10, each receiving the sound-suggestion condition and the no-sound, no-suggestion condition in different order. Sound and suggestion produced the following significant (p<.05) effects: 1) increased electrical stimulus levels required to elicit discomfort ratings; 2) decreased slope of somatosensory AER amplitudes plotted against stimulus intensity; and 3) decreased mean AER amplitudes. These AER effects were greatest in time bands centered on the P100 component. Prior exposure to the electrical stimuli also reduced AER slopes and mean amplitudes, but mostly in time bands centered on the P200 component.

Feedback effects and respiratory involvement in voluntary control of heart rate.

Abstract: One within-subject single session experiment involving 30 subjects and one between-subject single session experiment involving 42 subjects were performed to evaluate the effects of augmented sensory feedback and to specify the nature of cardiac-respiratory relationships during attempted bi-directional control of heart rate (HR). Subjects were instructed to attempt to control HR while maintaining a constant respiration rate (RR), and were provided with either no feedback, HR feedback, or HR and RR feedback of the “digital” proportional type. In addition to measures of heart and respiratory period, a measure of respiratory volume was included in the second experiment. Results of both experiments indicate that (1) subjects can significantly increase and decrease HR; (2) feedback does not affect the magnitude or consistency of HR control; (3) significant parallel changes in RR accompany changes in HR regardless of the amount of feedback provided; (4) significant increases in respiratory volume accompany HR increases; and (5) large magnitude HR changes arc produced by some subjects within the single session. Implications of these findings for the concomitance model of autonomic and central nervous system interactions; for single vs multiple training sessions; for the use of paced respiration; and for a learning model of HR control are discussed.

Sleep Deprivation and Measures of Emotionality in Rats

Abstract: Predictions from two theories which attempt to explain the function of active sleep (AS) were tested on 144 rats. Total sleep deprived, activity control, stationary control, active steep deprived, large pedestal control, or homecage control conditions were imposed on 30-day and 90-day-old subjects for 5 days. Open-field (OF) and startle response measures and adrenal and body weights permitted examination of changes in emotionality. Increases in OF activity and decreases in defecation in this paradigm are attributed primarily to AS deprivation, while reductions in quiet sleep may account for elevated startle responsivity in totally deprived subjects. Limited support for the Ontogenetic hypothesis is found in the treatment by age effect for OF activity, but the P-hypothesis prediction of increased emotionality in AS deprived subjects is contradicted by our data.