Habituation of the Orienting Response in Sleep

This experiment was designed with stimulus parameters deliberately chosen to maximize the probability of observing habituation of the orienting response (OR) in sleep: weak stimulus, short interstimulas interval. with test for both dishabituation and spontaneous recovery, Habituation of finger plethysmograph. heart rate, skin potential. and skin resistance responses was studied in delta sleep and RKM sleep in 46 male undergraduate volunteers. There was significant habituation of both finger plethysmograph and heart rate responses in both delta and REM sleep, as well as dishabituation and spontaneous recovery. None of these effects was observed in the electrodermal measures. Results were compared with other studies of habituation of the OR in sleep, as well as theories of habituation. The authors do not interpret the results as demonstrating learning during steep.     

Studies of Information Processing in Sleep

Two studies of information processing in normal human sleep are reported. In Experiment I it was found that subjects responded differentially in stage 2 sleep to “own name,”“other name,” and tone stimuli (decreasing in that order) as reflected in both the finger plethysmograph (FP)and heart rate (HR) and to some extent the EEG K-complex response, and similarly in REM sleep as reflected in the FP measure and to some extent the HR measure, but not in sleep stage 3–4. In Experiment II it was found that conditioned discrimination acquired during wakefulness persisted in sleep stage 4, as reflected in the FP and HR measures, and sleep stage 2, as reflected in the K-complex response, but not in REM sleep. Results are compared to other studies of information processing in sleep. It is concluded that the results appear to indicate differential availability of the mechanisms of long-term memory, short-term memory, and stimulus preprocessing in the various stages of sleep. The authors further noted a bifurcation of the autonomic nervous system in sleep into two discrete effector limbs: electrodermal and cardiovascular.     

Reinforcement of Spontaneous Electrodermal Activity: A Cross-Cultural Study in Japan

A within-subjects experimental design was used to examine the effects of contingent vs noncontingent reinforcement of spontaneous skin potential responses in Japanese subjects and the results were compared with previous data obtained from a comparable sample, of American subjects. The same overall pattern of differentiation between the two conditions of reinforcement was observed in both national groups, contingent reinforcement producing heightened rates of skin potential response relative to noncontingent reinforcement. Compared to the Americans, the Japanese showed more immediate differentiation between contingent and noncontingent reinforcement. The results are discussed in terms of previous crosscultural psychophysiological research.     

THE PERIPHERAL MECHANISM OF THE GALVANIC SKIN RESPONSE

Darrow held that the galvanic skin response (GSR) appears to be a complicated phenomenon because a number of events are sequentially involved. The mechanism resulting in the peripheral components of electrodermal phenomena is not complicated. Following excitation, sympathetic impulses to cutaneous tissues and subsequent release of acetylcholine account for initial negative polarity and resistance changes. When these incoming impulses are sufficiently persistent and strong, and when the cholinergic response of the sweat glands is sufficient, then if temperature and circulatory conditions are favorable, secretion by the sweat glands is initiated. Sweating is the major factor contributing to the positive potential and large drops in skin resistance during excitation, but at low levels of excitation, when skin resistance is high and before sweating has reached a critical level, epidermal activities other than those of the sweat glands may contribute appreciably to negative potential and resistance changes.     

Cardiovascular Components of Orienting and Defensive Responses

Data from an earlier study of physiological responses to affective visual stimulation were reanalyzed in an attempt to delineate the cardiovascular components of the OR and the DR. A HR response profile to unpleasant stimulation was obtained for each of 49 S_s by computing his average beat-by-beat HR response to slides of homicide victims. A hierarchical grouping procedure was then used to group these profiles in terms of similarity. An optimum grouping of three distinct groups of profiles emerged. Group A consisted of 9 S_s whose HR responses were accelerative in nature, Group D of 12 S_s who gave marked decelerative responses, and Group MD of 28 S_s who gave moderate decelerative responses. The cephalic vasomotor response given by Grup A to the homicide slides was vasoconstriction, while the response of Groups D and MD was vasodilation. The results provide some support for the suggestion that the OR consists of HR deceleration and cephalic vasodilation, while the DR consists of HR cceleration and cephalic vasoconstriction. However, it is possible that these “classic” patterns of cardiovascular activity occur in only some S_s and only under certain conditions, and that they may be obscured by the use of undifferentiated group data.     

AN EVALUATION OF FOREARM BLOOD FLOW AS A PSYCHOPHYSIOLOGICAL MEASURE

The usefulness of forearm blood flow (FBF) as a psychophysiological measure was investigated by comparing changes occurring during mental tasks in cardiovascular, sudomotor, and electromyographic measures. The measures were divided into those clearly physiologically independent and those physiologically related. ANOVA results showed that FBF, heart rate (HR), and skin conductance fluctuations (SCF) were equally reactive, and correlational analysis suggested that a close relationship existed between FBF, HR, and SCF, although correlations fell to near zero levels when intra-individual correlations were calculated with between task variance extracted. For some experimental purposes HR response may be considered equivalent to FBF response. The relationship between EMG and FBF was more variable, and tends not to support the idea that FBF is an indirect measure of muscle activity. The reliability of FBF in normal subjects at rest was poor, although it improved when measured during a simple task, and is probably stable enough for most experimental purposes.     

The Relationship Between Spontaneous and Stimulus-Correlated Electrodermal Responses in Simple and Discriminative Conditioning Paradigms

The purpose of the study was to explore the relationship between skin conductance fluctuations (SF) and skin conductance conditioning with designs permitting conclusions regarding both reactivity and conditioning. In the first experiment, involving simple delayed conditioning with a tone CS, a shock UCS, and an 8-sec ISI, groups high and low in SF during conditioning and sensitization were formed. Spontaneous fluctuations predicted magnitude of CS, pre-UCS, post-UCS, and unconditioned responses. Overall conditioning was significant only for the pre-UCS response, and for this measure the high SF group showed better conditioning than the low SF group. The second experiment involved discrimination training to pitch with shock UCS and an 8-sec ISI. Groups high, medium, and low in SF during conditioning were selected. Again, SF predicted magnitude of all response components. Reliable conditioning and significant relationship to SF was observed for CS, pre-UCS, and post-UCS responses. It was concluded that SF is related to both skin conductance reactivity and skin conductance conditioning.     

Response Requirements and Directional Fractionation of Autonomic Responses

Physiological responses were monitored while 27 male Ss were shown a series of 45 colored slides of homicide victims. Nine of the Ss were required to simply look at each slide (Nonraters), 9 were required to push 1 of 7 buttons, after each trial to indicate how disturbing they found the slide to be (Raters). Evidence for directional fractionation of autonomic responses to the slides was obtained for only the Nonraters. Their responses included cardiac deceleration, an increase in skin conductance, digital vasoconstriction, and cephalic vasodilation. The Raters responded with cardiac acceleration, an increase in skin conductance, and both digital and cephalic vasoconstriction. The Raters also showed a larger increase in tonic skin conductance over trials than did the Nonraters. To determine whether the physiological responses of the Raters were influenced by the requirement to make a motor response, 9 other Ss pressed a button after each slide. The physiological responses of these latter Ss were almost identical with those of the Nonraters. The results are consistent with the hypothesis that the requirement to rate the stimuli was associated with appraisal and cognitive elaboration. They also indicate that response requirements can have a profound effect upon autonomic responsivity.     

ACTIVATION STATES AS ASSESSED BY VERBAL REPORT AND FOUR PSYCHOPHYSIOLOGICAL VARIABLES

The present research was part of a program aimed at examination of the validity of controlled verbal reports of various activation states. A difference score design was used in which four psychophysiological measures and verbal ratings of various activation states were obtained in a baseline and an activation period from 41 female subjects. Verbal reports were then correlated with individual physiological measures and composites or indices of physiological measures. Specifically, two kinds of physiological index were employed, one in which the subject's physiological change score was represented by the single system showing the greatest change, and a second index weighted equally by all four physiological measures. The physiological index using the single system showing the greatest activation yielded slightly greater correlations with verbal report than the other index. Skin conductance and heart rate, the best combination of the four physiological systems measured, correlated as high as .62 with verbal report. The results were interpreted as demonstrating the usefulness and validity of controlled self report and the relative superiority of skin conductance and heart rate among other physiological systems in correlations with verbal report.     

To err is autonomic: error-related brain potentials, ANS activity, and post-error compensatory behavior

A two-component event-related brain potential consisting of an error-related negativity (ERN/Ne) and positivity (Pe) has been associated with response monitoring and error detection. Both the ERN and Pe have been source-localized to the anterior cingulate cortex (ACC)--a frontal structure implicated in both cognitive and affective processing, as well as autonomic nervous system (ANS) modulation. The current study sought to examine the relationships among the ERN, the Pe, two autonomic measures, and behavior. Electroencephalogram (EEG), heart rate (HR), and skin conductance (SC) were recorded while subjects performed a two-choice reaction-time task. In addition to the characteristic ERN-Pe complex, errors were associated with larger SCRs and greater HR deceleration. The ERN correlated with the number of errors, but was unrelated to ANS activity and compensatory behavior. Pe, on the other hand, was correlated significantly with SCR, and both SCR and Pe were significantly correlated with post-error slowing.     

Body Movements in Sleep During 30-Day Exposure to Tone Pulse

Body movements during sleep stages 2 and REM were measured using an artifact method to determine the effects of a tone pulse given every 22 sec, 24 hrs a day, over a period of 30 consecutive days in 10 Navy recruits, aged 19 to 23. The tone pulse produced no significant increase in the number of body movements during stage 2, but it increased body movements in REM sleep to a significant but small (3 movement increase per night) extent. The percentages of body movements observed in the first 7 sec after the tone pulse in sleep stages 2 and REM were significantly higher than those observed during the epochs 8–14 and 15–21 sec, and those observed to the pseudostimulus. The tone pulse used in this study redistributed or regulated the appearance of the body movements to the proximity of the noise, but did not increase the total number of body movements which appeared to be under endogenous control.     

Psychopathy and Physiological Activity In a Mixed-Motive Game Situation

Heart rate (HR) and skin conductance (SC) were recorded while 17 psychopathic (P) and 17 nonpsychopathic (NP) inmates (referred to as A) were engaged in a mixed-motive game situation with another S (referred to as B). On each trial A had to choose the intensity of shock to be delivered to himself and to B. B then was given a chance to retaliate, although his choices were actually overridden by the experimenter. A 10 sec tone (CS) preceded delivery of shock to each S. There were no differences between Groups P and NP in the intensity of shock chosen for themselves and for the other (B) Ss. Compared with Group NP, Group P gave small unconditioned skin conductance (SC) responses to shock directly received and to shocks delivered to the other S. There were no differences between groups in the unconditioned HR response to either direct shock (acceleration) or to shocks delivered to the other S (slight deceleration). Group P gave small electrodermal orienting responses (ORs) and anticipatory responses (ARs) to the CS preceding shock to self and shock to other; Group NP gave relatively large ORs and ARs to the CS preceding shock to self, and small ones prior to shock to other. Both Groups gave a biphasic conditioned HR response–acceleration followed by deceleration; each component was larger in Group P than in Group NP, and the acceleratory component in Group P appeared on the first trial. The electrodermal data were consistent with the view that psychopaths experience little fear arousal prior to reception of aversive stimuli by themselves or by others. It was suggested that the anticipatory HR responses of the psychopathic Ss were part of an adaptive response that helped them to cope with stress.     

Interactions of Marijuana and Induced Stress: Forearm Blood Flow, Heart Rate, and Skin Conductance

To examine the interaction of marijuana and an induced state of stress, on both subjective and physiological measures, two groups of 15 subjects each were given a mental arithmetic task to perform. The sequence of events was 10 min each of pre-stress, stress, post-stress, intoxication (about 20 min), pre-stress, stress, post-stress. In the intoxication phase, one group smoked marijuana containing 14 mg Δ⁹-THC while the other group smoked a placebo. The dependent variables were forearm blood flow (FBF), heart rate (HR). and skin conductance (SC), and a subjective measure of stress–the Multiple Affect Adjective Checklist (MAACL). The results revealed all physiological variables to be reactive to the stress task. In addition, marijuana intoxication produced reliable increases in both pre-stress HR and FBF, and yet the physiological response to the post-intoxication stress period showed no significant decrement when compared In the placebo group. Discussion of these results centered around marijuana's effects on tonic and phasic reactivity.     

Heart Rate and Skin Conductance in Anticipation of Shocks With Varying Probability of Occurrence

In Experiment I,Ss in each of four groups were given 8 shocks in either 8, 11, 16, or 32 trials, confounding probability with number of trials. Each trial was a countdown period of 30 sec, with an ITI of 30 sec. There were no shock probability effects using either heart rate (HR) or skin conductance (SC), with respect either to average within trial changes or to average pre-shock levels relative to rest. In every group after a large acceleration in Trial 1, HR subsided and stabilized; SC rose steadily throughout the session. In Experiment II, Ss in each of four groups were given either 5, 10, 15, or 20 shocks in 20 trials, confounding probability with number of shocks. In addition to the large HR acceleration in the first trial, there were in this case between-group differences in HR, which were a direct function of number and probability of shocks. Skin conductance did not discriminate the groups, though it rose in all groups both within and across trials. Experiment III, a partial replication of Experiment II, showed that the HR differences in Experiment II failed to repeat when the shock intensity was reduced; and SC no longer increased over trials.     

HEART RATE, SKIN RESISTANCE, AND REACTION TIME OF MONGOLOID AND NORMAL CHILDREN UNDER BASELINE AND DISTRACTION CONDITIONS

Reaction time, body movement, heart rate, and skin resistance of Mongoloid and “normal” control children were evaluated under baseline and distraction conditions. Relative to controls, Mongoloids demonstrated (1) slower reaction time under both conditions, (2) a reduced skin resistance response and fewer heart rate fluctuations during the baseline period, and (3) fewer skin resistance fluctuations during the distraction condition. Furthermore, skin resistance fluctuations were negatively correlated with reaction time, and heart rate fluctuations, although not significant, were in the same direction. These findings offer some support for the theoretical assertions of Lacey and Lacey (1958) that spontaneous activity is related to motor impulsivity, cortical activity, and general skeletal-motor functions. Body movement was negatively related to these measures of spontaneous activity and thus cannot be invoked as an explanation for the findings.     

Differences in Readiness Potential Associated with Push-Button Construction

For the purposes of psychophysiological experiments that require an operant response, a push-button switch that utilized the skin resistance of the thumb was constructed. The skin contact push-buton (SC-PB) produced a more negative pre-response slow potential shift recorded at the vertex than the standard push-button (S-PB), using 6 subjects in a repeated measures design.     

Psychological and Physiological Variables Associated With Large Magnitude Voluntary Heart Rate Changes

Forty subjects, given binary and proportional auditory and visual feedback and asked to raise and lower their heart rate on signal, were able to produce increases of up to 46 bpm and decreases of up to 14 bpm, with a mean increase over 5 experimental days of 11 bpm and a decrease of 5 bpm. Increases in both diastolic and systolic blood pressure and increases in skin potential level and number of skin potential responses accompanied voluntary increases in heart rate but not decreases. Subjects with the highest resting heart rate variability and skin potential level were best able to raise their heart rate. Subjects with the highest resting heart rate and highest resting heart rate variability were best able to decrease the heart rate. Subjects with high Ego Strength scores (or low Welsh's Factor A scores) on the MMPI were best able to control their heart rate. The Ego Strength score, resting heart rate, and resting heart rate variability were all significantly intercorrelated. Subjects showed marked individual differences in ability to control heart rate, although there was a significant correlation between ability to raise and ability to lower heart rate.     

Overextinction of the Evoked Skin Conductance Response: An EEG Study

The present study was designed to investigate Sokolov's (1963) proposal that overextinction of the orienting response (OR) is related to sleep onset. A series of 80 auditory stimuli was presented to 22 male and female Ss. Although re-evocation of the skin conductance response (SCR) component of the OR occurred, in the majority of Ss, after 40–50 stimulus presentations, this was not accompanied by any change in cortical alertness as measured by integrated EEG output in three frequency bands (2–4, 4–8, and 8–13 Hz). However, the results did indicate that Ss displaying SCR return required more stimulus presentations before initial SCR habituation and displayed more spontaneous fluctuations in skin conductance during the prestimulus period than did non-return Ss. Within the return group, latency of SCR return was negatively related to both spontaneous activity during the prestimulus period and number of stimuli to initial habituation.     

Conditioned Orienting and Defensive Responses

Physiological responses were recorded while 9 females (Group P) who Feared spiders and 9 who did not (Group N) viewed “neutral” and spider slides in a delayed, differential conditioning procedure. Two different tones were the conditioned stimuli, and 12 neutral and 12 spider slides the unconditioned stimuli. Each CS was 11 sec long. Only Group P showed differential HR conditioning-anticipatory acceleration to the CS preceding the spider slides (CS+). For both groups, cephalic vasoconstriction was greater to the CS+ than to the CS-. However, with repeated trials Group P's response to the CS+ became more prolonged, so that by the last block of trials contraction persisted until the end of the CS period. Group N's response, on the other hand, continued to be constriction followed by rapid recovery to the prestimulus level. Although significant electrodermal conditioning did not occur, Group P tended to give larger anticipatory SC. responses to the CS+ than to the CS-. There was little evidence of somatic-autonomic coupling on a group basis. When considered along with post-experimental reports, the results indicate that at least some of the cardiovascular components of the defensive response (DR) are conditionable.