Bidirectional operant conditioning of heart rate in rats with sucrose reward

Sucrose was used to reinforce heart rate (HR) increases in one group of unrestrained rats and to reinforce decreases in another. A third group received noncontingent sucrose presentations, and a fourth was presented with an empty dipper. After 10 conditioning sessions HR, as measured by changes in tonic levels, was significantly greater in the Fast group than in the Noncontingent group, which in turn maintained significantly higher levels than the Slow group. There was no difference between the Noncontingent and No-sucrose groups. Behavioral observations indicated that the Fast animals increased the percentage of time spent in such high-HR categories as rearing and walking; however, there were no corresponding systematic decreases in the Slow animals. Moreover, the Fast and Slow groups differed significantly with regard to the HRs associated with five behavioral categories. The overall pattern of results suggests that some degree of cardiospecific effect may have been exerted by the operant contingencies.     

Muscle tension in human operant heart rate conditioning

The physiological mechanism involved in human operant heart rate conditioning is not known. If skeletal muscle tension is a mediator, it should be possible to generate significant heart rate increases by inconspicuous voluntary muscle tension. Eleven subjects were instructed to generate inconspicuous muscle tension for 90-second periods. No gross muscle movements were observed, but average heart rate during the trials was over 13 beats-per-minute greater than pre-trial base lines. Respiratory pattern changes and surface electromyogram changes did not reliably correlate with heart rate increases. Inconspicuous muscle tension could be a mediator in human operant heart rate conditioning, and cannot be ruled out by absence of change in respiratory pattern or electromyogram.     

Differential reinforcement of other-than-vocalization as a control procedure in the conditioning of infant vocalization rate

The purpose of the present study is to demonstrate reinforcement control over infant vocalization rates using a DRO schedule to control for elicitation of social stimulation. Mothers of four 2 1/2- to 3-month-old infants provided social reinforcement for their infants' vocalization under two schedules: continuous reinforcement (CRF) and differential reinforcement of other-than-vocalization (DRO). In a repeated-reversal single-subject experimental design, all four infants produced systematically higher vocalization rates during CRF, even though densities of social stimulation during DRO were equal to or greater than densities provided during CRF. Thus, whatever its elicitation value, social stimulation may reinforce infant vocalization rates.     

Intracerebral scopolamine administration attenuates Pavlovian heart rate conditioning in the rabbit

Scopolamine hydrobromide was injected into the a) septum, b) dorsal hippocampus, or c) lateral ventricles of conscious rabbits via bilateral chronic indwelling cannulas. The cardiac orienting reflex (OR) and heart rate (HR) classical conditioning were assessed. A fourth group of animals received injections of the vehicle solution into these same brain areas and were otherwise similarly trained. Scopolamine had no effect on the cardiac OR produced by unreinforced tone stimuli. The OR consisted of pronounced bradycardia that habituated over successive trials in all groups. The HR change during classical conditioning also consisted of bradycardia. However, these conditional HR changes were attenuated by scopolamine injected into the septum and lateral ventricles, but were not affected by injections into the dorsal hippocampus. These results suggest that centrally applied scopolamine may affect a central nervous system associative process, and not a mechanism directly involved in primary bradycardia.     

Self-efficacy as a predictor of ability to learn control of heart rate increase with and without biofeedback

Abstract

The usefulness of self-efficacy as a predictor of success in controlling heart rate increase with and without biofeedback was investigated in an experimental study on 60 adult subjects. The first part of the study measured heart rate increase control without biofeedback training, the second part measured heart rate increase control with biofeedback training and a posttest measured subsequent heart rate increase control without biofeedback. The results revealed that higher levels of self-efficacy were predictive of success in controlling heart rate increase without biofeedback, but not with biofeedback.     

Pavlovian conditioning with ethanol and lithium: effects on heart rate and taste aversion in rats

Rats received paired injections of either ethanol or saline as the conditioned stimulus and lithium chloride as the unconditioned stimulus (US) in a Pavlovian differential conditioning paradigm. Lithium chloride evoked a large deceleration in heart rate (80-100 beats per minute) as an unconditioned response. As a result of 10 conditioning trials, the substance paired with LiCl elicited a lower average heart rate than that elicited by the unpaired substance. Moreover, animals that received ethanol-LiCl injections subsequently were more averse to the taste of ethanol than animals receiving saline-LiCl pairings. However, there were no differences in ethanol's ability to serve as the US to induce an aversion to a novel flavor solution (i.e., the Avfail phenomenon was not observed). The overall pattern of results underscores the value of using multiple indexes of learning in drug-drug conditioning paradigms.     

Concomitant Pavlovian conditioning of heart rate and leg flexion responses in the rat

Pavlovian conditioning was studied in male Fischer 344 rats using tones as the conditioned stimulus (CS) and footshock as the unconditioned stimulus (UCS). Different groups of animals received (a) contiguous CS-UCS pairings with a 0.5 sec CS, (b) contiguous CS-UCS pairings with a 4.0 sec CS, or (c) a random sequence of noncontiguous tones and shocks using either a 0.5 sec or a 4.0 sec CS. Heart rate (HR) and leg flexion (LF) responses were recorded. Leg flexion conditioning occurred only in the 0.5 sec contiguous group. Decelerative HR CRs occurred only in the 4.0 sec contiguous group. Accelerative HR changes occurred in the other two groups but were significantly greater in the 0.5 sec contiguous group. These results are similar to but not identical to those obtained during eyeblink or nictitating membrane conditioning in rabbits, and suggest that the topography of the Pavlovian HR CR is dependent on the simultaneous occurrence of other classically conditioned responses.     

Varying temporal location of a conditioned stimulus in heart rate conditioning ofMacaca mulatta

The several functions that a stimulus can assume were investigated in a Pavlovian conditioning procedure. The subjects were six rhesus monkeys; the response under observation was heart rate. The conditioning began with a temporal separation of zero between a signal and a regularly repeating electric shock; the signal was then moved to a series of earlier locations in the inter-shock interval. After six sessions at each location, two sessions followed in which only the shock was delivered periodically. The findings included: (1) A two-phased conditioned cardiac rate response seen at the first location became more multiphasic and irregular during longer intervals between signal and shock; (2) the location where the conditioned response peaked became increasingly variable as the signal was moved back, but this variability maintained a constant proportion to the signal-shock interval; and, (3) heart rate during a presignal period, and during a comparable period in shock only sessions, was generally deceleratory early in training and acceleratory thereafter. Sessions with the signal showed heart rate in the presignal period to have become acceleratory earlier in training than sessions with shock only. The data pertain to stimulus control over heart rate as a function of: (A) the temporal proximity of a signal to an aversive stimulus; and, (B) the presence or absence of the signal. The use of appropriate response units in cardiac conditioning is also discussed.     

Classical aversive conditioning of heart rate in curarized rats at different blood gas levels

In an effort to examine whether normal blood gas tensions were essential for conditioning, paralyzed rats received a classical aversive heart rate (HR) conditioning session while respirated at different peak expired CO₃ values. After the session, arterial blood was drawn for analysis. That peak expired CO₂ was effective in manipulating Pco₂ was indicated by a significant correlation (r = 0.594, df = 17, P < 0.05). In addition, only rats with blood gas values similar to those of anesthetized controls displayed a discriminated HR CR. These animals also had lower baseline HRs and greater HR variability. Further, 7 of the 9 rats with normal blood gas values were respirated at peak expired CO₂ values from 5.0–5.1 per cent, and no animal ventilated within this range displayed abnormal values. These findings suggest that previous difficulties in obtaining classical and operant conditioning in paralyzed animals may, in part, be attributable to inadequate ventilation.     

Changes in heart rate during feedback control of respiration

Subjects received one of eight treatments: practice at increasing heart rate with heart-rate feedback, practice at decreasing heart rate with heart-rate feedback, practice at increasing heart rate without heart-rate feedback, practice at decreasing heart rate without heart-rate feedback, practice at increasing respiration rate with respiratory feedback, practice at decreasing respiration rate with respiratory feedback, practice at increasing respiration rate with respiratory instructions only, practice at decreasing respiration rate with respiratory instructions only. Heart rate, Respiration rate, and Respiration depth were measured. Analysis indicated that subjects who controlled respiration with respiratory feedback reliably increased and decreased heart rate; subjects who controlled respiration with respiratory instructions only reliably increased but not decreased heart rate; subjects in the respiratory-feedback conditions showed higher heart-rate increase and decrease than heart-rate increase and decrease of subjects in the other six conditions.     

Anxiety, perception, and control of heart rate

8 women and 8 men took Cattell's IPAT-anxiety questionnaire and later McFarland's test of ability to perceive heart activity. The second test involved subjects' tracking their own heart rates, then they enrolled in an EKG biofeedback session to evaluate ability to increase and decrease heart rate from subjects' resting baselines. At the end of the session each subject completed Blanchard, et al.'s questionnaire to specify the cognitive strategies used for heart-rate control. Heart rate, abdominal respiration rate, respiration amplitude, EEG percent power in theta, alpha, and beta bands were evaluated. Success of heart-rate decrease seemed to depend mainly on activity levels: the subjects who achieved high scores on the activity test decreased heart rate significantly better than did low scorers. The relationship between scores for perception of heart and increases in heart rate was nonsignificant: increased heart-rate seemed to depend on differences in respiration between the rest and periods of increase. The significant, negative correlation between trait anxiety and perceptions of heart activity suggested that anxiety affected subjects' ability to perceive heart rate. The theta EEG power of the right hemisphere was significantly higher in subjects scoring high than for those low in perception of heart activity. During heart-rate increase tasks subjects mainly reported use of 'arousal responses,' similarly during heart-rate decrease tasks they reported use of relaxation responses.