Paced respiration and heart rate control

E's Presence: Effect on S's Performance

This study was designed to see if the presence of E was sufficient to produce “demand characteristics” in a psychological experiment. Two physiological indices, electromyogram and heart rate, measured performance of a task, i.e., not to respond to a tone. E's presence facilitated S's ability not to respond as indicated by EMG. E's presence had a facilitating effect and “demand characteristics” of psychological experimentation appear to exist.

Regions of cardiorespiratory synchronization in humans under paced respiration

Cardiorespiratory synchronization under paced respiration is studied systematically as the respiration frequency is changed between 3 and 30 breaths per min. We plot a one-dimensional cut of the classical picture of synchronization regions along the line defining the current breathing amplitude. The existence of n:m synchronization regions of finite width is demonstrated for each of six subjects studied. The statistics of the different types of synchronization and their stability are discussed.

Personality correlates of bidirectional heart-rate control

This study examined the combined effects of personality with instruction and treatment variables in human operant heart-rate conditioning. The Edwards Personal Preference Schedule was administered to 50 subjects tested for bidirectional heart-rate control during no-feedback and analogue auditory feedback conditions. Findings indicated that relative to pre-trial baselines, subjects were able significantly to alter heart rates according to instructed direction of change, but treatment effects for augmented sensory feedback were not reliable. Correlational analyses employing personality variables demonstrated that different traits define successful speeding and reduction performance. Further, post hoc analyses for personality high-low classification X treatment X instructions effects indicated that personality variables of succorance and abasement moderated treatment effects for heart-rate reduction. Questions are raised concerning the efficacy of proportional auditory treatment in biofeedback training.

Instrumental cardiovascular conditioning: a review

This paper reviews experiments, hypotheses, and current controversies about instrumental cardiovascular conditioning. Demonstrations of such conditioning in curarized animals challenged a differentiation between instrumental and classical learning on the basis of their respective effector systems but did not prove direct operant learning by the autonomic nervous system. In humans, ethical prohibition of curarization and lack of adequate controls for respiration and muscle tension have resulted in incomplete understanding of the roles of voluntary, somatic mediators. Despite a variety of potential clinical applications of biofeedback, the available literature lacks studies of its efficacy compared to more standard modes of therapy. The physiological mechanisms and central neural pathways involved in instrumental cardiovascular conditioning remain almost totally unknown.

Efficacy of pattern feedback for the dissociation of heart rate and respiration rate

The present study assessed the efficacy of pattern feedback for producing integrative and dissociative patterns of heart rate (HR) and respiration rate (RR). 60 uninformed subjects were assigned to six groups in which beat-by-beat feedback was contingent upon production of a specific pattern of increased ( ), decreased ( ), or unchanged (=) HR and RR during 11 feedback trials. Concomitant changes in respiratory volume and general activity (GA) were also recorded. Groups given feedback for HR and RR changes in the same directions (HR RR and HR RR ) ANd for changes in opposite directions (HR RR and HR RR ) were generally unable to produce the respective patterns, indicating that pattern feedback does not enable subjects to produce a wide range of HR-RR patterns. However, evidence of dissociation of HR and RR was obtained in the HR RR= and HR RR= groups in which HR changed significantly in the appropriate directions without significant changes in RR. These results are not consistent with the view that RR changes are necessary for HR control, although significant concomitant changes in respiratory volume and GA indicated that HR control was non-specific relative to these variables.

Discriminative control of the vaginal vasomotor response

With use of a discriminative control procedure and operant techniques, women significantly increased their vaginal pulse amplitude (produced vaginal vasodilation) but did not significantly decrease vaginal pulse amplitude (produce vaginal vasoconstriction). Acquisition of vaginal pulse amplitude control was rapid with no significant improvement over trials or the 5 experimental days. Specificity of vaginal pulse amplitude control occurred in relation to the other vasomotor responses, including vaginal blood volume and digital pulse amplitude. Vagnial pulse amplitude changes were not related to somatic-muscular, respiratory, or heart-rate changes. Women who used oral contraceptives were better able to control vaginal pulse amplitude than women who used other forms of birth control. Although the sexual behavior of these two groups and did not differ, women in the latter group tended to be more clitorally oriented.

Effect of demand characteristics on heart rate during a behavioral avoidance test

A 2 X 2 experimental design utilized two levels of verbally reported snake fearfulness (high-low) and two levels of experimental demand (high-low) with 16 college student subjects during a behavioral avoidance test. Subjects given high-demand instructions for heart-rate increase increased their heart rate more than subjects given low-demand instructions. Results were specific to heart rate, as demand produced no effects on approach behaviors or fear ratings. Heart rate during the behavioral avoidance test was shown to be as susceptible to experimental demand as other studies have shown approach behaviors to be influenced.

Within-subject control designs and voluntary bidirectional control of cardiac rate: methodological comparison between pre-experiment and pretrial baselines

The purpose of this study was to compare two methods of analyzing the effects of exteroceptive feedback training on the voluntary bidirectional control of human cardiac rate with the use of a within-subject control design. In this design heart rate (HR) during an experimental period (increase or decrease) is compared with that recorded during some other control period, generally a baseline "rest" period. Ten male undergraduates were instructed to control HR and given visual feedback of heart activity. Trials on which Ss were to raise and to lower HR were both given in a single training session. The data were analyzed in two ways: (a) cardiac rate during HR control periods was compared to an initial pre-experimetn baseline; (b) cardiac rate during HR control periods was compared to a running pretrial baseline. The results support the argument that the former procedure fails to take account of habituating levels of cardiac rate and favors finding large magnitude decreases in HR but small increases, whereas the latter procedure favors finding large magnitude increases but small decreases. It is suggested that magnitude of directional control will be artifactual when initial values are used to assess change. Contaminating influences on the running pretrial baseline were also discussed.

The voluntary control of heart rate under differential somatic restraint

The purpose of this investigation was to test the hypothesis that subjects (Ss) can exert voluntary, bidirectional heart rate (HR) control in the absence of concomitant changes in respiration rate (RR) and muscle activity (chin EMG). Feedback-assisted HR control was studied under four experimental conditions involving increasing levels of somatic restraint: (a) No somatic controls, (b) RR pacing, (c) EMG feedback, to maintain constant muscle activity, and (d) RR pacing plus EMG feedback. Fifteen Ss, eight females and seven males, were assigned to each of these four conditions (N = 60). The HR control task involved ten increase and ten decrease trials in random order, each lasting 60 sec and preceded by a 60-sec resting baseline period. The results indicated that Ss produced significant HR increases (Xdelta = +3.4 bpm), but were unable to effect decreases (Xdelta = -.3 bpm). Furthermore, the magnitude of the obtained HR changes did not differ by experimental condition, i.e., by level of somatic restraint. While concomitant bidirectional RR changes were found, the pacing procedure effectively reduced, and on HR increase trials, nearly eliminated, RR involvement. No increases in EMG activity were found on HR increase trials for any of the four experimental conditions, whereas all groups showed some EMG decreases on HR deceleration trials. With respect to the question of somatic mediation of autonomic control, it is concluded that HR increases produced under paced respiration "favor" an interpretation of unmediated HR acceleration.

Instructional, pacing, and feedback control of respiratory behavior

Procedures designed to affect respiration rate and amplitude were assessed for 4 groups of 8 subjects each. The groups were exposed to combinations of procedures providing feedback for decreasing respiration amplitude, pacing respiration rate, and instructions on rate and amplitude of breathing. After an initial baseline, effects were examined during both treatment and self-management phases for respiratory activity and concurrent heart-rate and electromyogram activity. Reliable effects of pacing on respiration rate, and a slight, but non-significant effect on amplitude were observed. No effects were observed for any heart-rate or electromyogram measures.

The impact of two different reinforcers on conditioned operant heart-rate acceleration and deceleration

The effects of two types of reinforcers on operant heart-rate acceleration and deceleration conditioning were examined over a number of sessions. The initial use of monetary reinforcement facilitated discriminative pre-trial to trial heart-rate acceleration during sessions utilizing both monetary reinforcement and visual feedback. The initial use of visual feedback did not produce such discriminative control, but the subsequent use of monetary reinforcement resulted in increases in pre-trial and trial heart rate over sessions. No effects due to type of reinforcement were noted for heart-rate deceleration. Increases and decreases in cardiovascular functioning were imposed upon a background of increased skin responding. The cardiovascular responses that developed over sessions appeared to be relatively independent of changes in skin response.

Role of feedback in voluntary control of heart rate

The relative effectiveness of biofeedback techniques on the voluntary control of heart rate was examined by randomly assigning 32 Ss to one of four feedback conditions in a bi-directional heart-rate control task: (1) no feedback, (2) binary feedback--S was signaled when an interbeat interval had changed in the correct direction, (3) "real-time," proportional feedback--S was provided information about the relative duration of successive interbeat intervals, and (4) numerical, proportional feedback--each interbeat interval was represented as a numeral indicating its relationship to pre-trial mean by direction and magnitude. Significant over-all heart-rate changes were evidenced for both increase and decrease directions, but no differences were found between the feedback conditions. While these data suggest that feedback may be a relatively insignificant factor in voluntary heart-rate control, it was recommended that further investigation examine the role of feedback within the context of other training, mediating and motivational variables.

Effects of motivation upon performance of an operant heart-rate control task

The effect of potential monetary reward upon performance of a heart-rate control task was evaluated. There were no significant differences in average heart-rate control between Ss who were offered payment for successful control and those who were not offered payment. Greater variability in performance was found among Ss who were offered payment as opposed to those who were not. This finding is discussed in relation to verbal reports made by Ss following experimental sessions. Some additional data on changes in performance over time on the heart-rate control task are presented.