Operant conditioning of skin resistance tonic levels

The purpose of the current investigation was to determine whether increases and decreases in skin resistance tonic level could be controlled by individuals given discrete visual feedback of such activity. Thirty-six male undergraduate students served as subjects. They were assigned randomly in equal numbers to four groups; two of the groups received accurate feedback of skin resistance level changes and two received inaccurate feedback. The two accurate-feedback groups differed with respect to the order in which increases and decreases in skin resistance level were reinforced. Each noncontingent group was matched with one of the contingent groups in terms of reinforcement density. The results indicated that accurate feedback produced skin resistance level changes consistent with the type of reinforcement employed. However, operant control was not clearly sustained subsequent to a reversal in the type of tonic level change reinforced. Some problems related to the clinical application of skin resistance level training are discussed.     

Changes in autonomic responding to stress after practice at controlling heart rate

Subjects in this experiment viewed a stressful film and then received one of five treatments: (a) practice at increasing heart rate without feedback, (b) practice at decreasing heart rate without feedback, (c) practice at increasing heart rate with feedback, (d) practice at decreasing heart rate with feedback, or (e) a control condition. Subjects then returned on the following day, practiced controlling heart rate again (or sat quietly, for subjects in the control condition), and then viewed the stressful film again. Heart-rate results indicated that subjects in both feedback groups manifested tonic decreases in heart rate from the first viewing of the film to the second, whereas subjects in both of the no-feedback groups manifested no changes in heart rate between viewings, and subjects in the control condition manifested increases in heart rate between viewings. However, all five groups of subjects displayed phasic increases in heart rate during specific stressors in the film during both viewings. The tonic changes in heart rate noted between viewings of the film for the feedback groups were not accompanied by parallel changes in electrodermal activity or respiration rate. Self-report ratings of subjects' beliefs about ability to control heart rate were significantly correlated with the tonic changes in heart rate that were noted between viewings of the stressful film.     

A device for functional residual capacity controlled biofeedback of respiratory resistance

A computer-aided procedure is presented providing subjects with analogous visual feedback of respiratory resistance, which is continuously measured using the forced oscillation method. Simultaneous pneumotachographical control of the breathing volume curve makes it possible to prevent reinforcement for decreases of respiratory resistance which are due to increases of functional residual capacity (FRC). Lung hyperinflation is an unsuitable way to reduce respiratory resistance; if it occurs, feedback is interrupted until the subject decreases his FRC to its initial level. Analysis of the data of 15 adult asthmatic subjects which underwent a 12-sessions feedback training showed that no substantial changes of FRC appeared within feedback trials. Advantages of this new biofeedback technique compared to other procedures are discussed with regard to volume control and feedback signal.     

Biofeedback control of skin potential level.

This study explored the possibility of using biofeedback to arrest spontaneous declines in tonic electrodermal levels. For 3 days, 10 subjects (S) received 20 minutes of training in increasing skin potential level (SPL) negativity (arrested declines), followed by 20 minutes of training in decreasing SPL negativity (facilitating declines), with reverse order for half of the Ss. Simultaneous analogue and binary feedback of SPL were used. Training in the direction of SPL increases resulted in arrest of spontaneous declines in SPL negativity but did not result in large-magnitude increases above baseline. Training in the direction of SPL decreases facilitated declines in SPL. The absolute mean difference between the increase condition and the decrease condition on the 3rd day was 8.28 mV. Correlations suggested that considerable intraindividual variability may have been independently related to the Locus of Control personality dimension and to a Law of Initial Values limitation on SPL change. It was concluded that SPL was controllable to the extent of facilitating or arresting spontaneous declines.     

Control of cardiac response under aversive stimulation

The relative heart rate effects of biofeedback training, deep muscle relaxation, and a no-feedback/music procedure were compared during two criterion situations. The first consisted of a 25-min training period during which subjects received the assigned treatments. The second consisted of the pre- to posttraining reductions in heart rate reactivity to a series of aversive tone-shock trials. On the first criterion, the heart rate decreases of the feedback and no-feedback/music groups were not clearly distinguishable; however, both groups fell significantly below the muscle-relaxation group. By contrast, on the second criterion, the three groups were clearly distinguishable, with feedback subjects evidencing the most heart rate control, followed by the muscle-relaxation and no-feedback/music groups, respectively. On the segment of the posttraining aversive trials conducted in the absence of the feedback signal, transfer of heart rate control was incomplete for feedback subjects, but still remained below the level of the other two groups. Training effects were more pronounced on tonic than on phasic heart rate changes. The difference between the two criterion situations suggests the possible need for and feasibility of employing a situational arousal methodology in evaluating the extent and limitation of physiological training procedures.     

Effects of discrete visual feedback on the electrodermal control of a stressful situation

Two groups of human volunteers received three sessions of discriminated avoidance and punishment with the skin resistance response (SRR) as the operant. During each session one group (feedback) received three 6–8-min periods of Sidman avoidance of a 1.5-mA shock (R-S=40 sec, S-S=35 sec) mixed with three periods of punishment with a 20-sec time-out after each period. The avoidance and punishment periods were signaled by red and green lights, and a circle appeared superimposed on the discriminative stimuli for the duration of a criterion response. A second group (no feedback) received the same conditions as the feedback group except that no circle appeared. Instructions to the subject were not informative regarding experimental events. Subjects made significantly more SRR's during avoidance, a contingency in which responding prevented shock, than during punishment, a contingency in which responding produced shock. A reliable four-way interaction suggested that the feedback stimulus curtailed a tendency for avoidance response rate to diminish within and between experimental sessions. The data are considered as evidence for electrodermal (autonomic) control of two different stressful situations, and the potential value of the paradigm for establishing tonic autonomic arousal and suppression is considered.This research was supported by the Charles L. Mix Memorial Fund. The data were collected in part by M. D. McCrary.     

The production and generalization of large-magnitude heart rate deceleration by contingently faded biofeedback

Eight subjects were taught to decrease their heart rates via biofeedback training. Four of these received contingently faded, beat-by-beat analogue feedback and contingent reinforcement each time their performance met a specified and adjusting criterion. The other four received continuous, beat-by-beat analogue feedback, but not the contingent reinforcement. Subjects in the two groups were yoked to ensure equal densities of reinforcement. Subjects in the first group were asked to decrease heart rates 15% from baseline and were then trained using only 75%, 50% and 25% of beat-by-beat feedback. It was hypothesized that the immediate reinforcement of appropriate behavior and the contingent fading(following mastery) of feedback would aid in the generalization of the response. Following completion of all criterion steps or 10 training sessions, whichever came first, all subjects were tested with no feedback and no contingent reinforcement. The group receiving contingently faded feedback training showed a significantly greater heart rate decrease in the training sessions and also the test session. These results were interpreted as indicating that biofeedback can be conceptualized as an operant conditioning paradigm, and that the use of operant techniques may help subjects produce clinically significant changes.This research was supported in part by a grant to Robert J. Gatchel from the National Heart, Lung, and Blood Institute (Grant No. NIH HL 21426-01).     

Feedback control of human alpha rhythm from the central area

Twenty subjects, aged 17 to 25, were given from 5 to 10 sessions of training in controlling alpha. They were divided into three groups, respectively reinforced for increasing alpha from the central area, reinforced for decreasing alpha from the central area, and given noncontingent reinforcement. Compared with the initial baseline, the alpha of the noncontingent subjects did not change, while those reinforced for increases were reliably higher and those reinforced for decreases reliably lower than the noncontingent group. A slight trend toward improvement during successive sessions was not reliable. Since the experiment was conducted in the Soviet Union, the subjects had no expectations of an “alpha experience.” Although tests showed a slight elevation in mood at the end of the sessions, there were no differences among the groups. There was an increase in reports of fatigue after the training sessions. There were no reports of using visual or somatomotor maneuvers as a means of controlling alpha. Furthermore, alpha rhythm control was not found to be consistently correlated with changes in heart rate, respiration, or mood, as determined by cross-correlation analysis.     

Feedback control of human alpha rhythm from the central area.

Twenty subjects, aged 17 to 25, were given from 5 to 10 sessions of training in controlling alpha. They were divided into three groups, respectively reinforced for increasing alpha from the central area, reinforced for decreasing alpha from the central area, and given noncontingent reinforcement. Compared with the initial baseline, the alpha of the noncontingent subjects did not change, while those reinforced for increases were reliably higher and those reinforced for decreases reliably lower than the noncontingent group. A slight trend toward improvement during successive sessions was not reliable. Since the experiment was conducted in the Soviet Union, the subjects had no expectations of an "alpha experience." Although tests showed a slight elevation in mood at the end of the sessions, there were no differences among the groups. There was an increase in reports of fatigue after the training sessions. There were no reports of using visual or somatomotor maneuvers as a means of controlling alpha. Furthermore, alpha rhythm control was not found to be consistently correlated with changes in heart rate, respiration, or mood, as determined by cross-correlation analysis.     

Tonic and phasic stimulus control of blood pressure responses using opposing unconditional stimuli

The transswitching paradigm was used in the present study to investigate the effects of tonic (long duration) environmental stimuli paired with opposing unconditional stimuli on human blood pressure. Sixty volunteers participated for two sessions, one week apart. Subjects were presented with a pseudorandom sequence of four trials of red lights (five minutes each) and four trials of blue lights (five minutes each) within each session. All subjects received the cold pressor test during the red lights. During the blue lights, half the subjects received warm water and the other half received a neutral temperature water. Subjects received the presentations of the water in one of three methods: as determined by the experimenter, preceded by a warning signal, or self-administered. The results indicated that conditional and unconditional responses during the red lights were progressive increases in blood pressure. During the blue lights associated with warm water, conditional and unconditional responses were often progressive decreases in blood pressure. The method of administration of the water affected the magnitude of the unconditional responses. Evidence for phasic stimulus control was not as unequivocal as tonic stimulus control. The present results indicated that it is possible to modify blood pressure in two directions (increases and decreases) when two high contrast, opposing unconditional stimuli are presented.     

Biofeedback control of skin potential level

This study explored the possibility of using biofeedback to arrest spontaneous declines in tonic electrodermal levels. For 3 days, 10 subjects(S) received 20 minutes of training in increasing skin potential level (SPL) negativity (arrested declines), followed by 20 minutes of training in decreasing SPL negativity (facilitating declines), with reverse order for half of theSs. Simultaneous analogue and binary feedback of SPL were used. Training in the direction of SPL increases resulted in arrest of spontaneous declines in SPL negativity but did not result in large-magnitude increases above baseline. Training in the direction of SPL decreases facilitated declines in SPL. The absolute mean difference between the increase condition and the decrease condition on the 3rd day was 8.28 mV. Correlations suggested that considerable intraindividual variability may have been independently related to the Locus of Control personality dimension and to a Law of Initial Values limitation on SPL change. It was concluded that SPL was controllable to the extent of facilitating or arresting spontaneous declines.     

Specificity of finger pulse volume feedback during relaxation

The effect of biofeedback during brief periods of relaxation was examined. Two groups (10 subjects in each group) were asked to relax as completely as possible during a series of six 3-minute relaxation periods in each of two 1-hr sessions. One group received biofeedback based on finger pulse volume (FPV) during the relaxation trials, while the other group received no biofeedback. Measures of heart rate, respiration rate, skin conductance level, and FPV were recorded during the sessions, and subjective ratings concerning relaxation were obtained after each session. The results showed that FPV scores for the groups differed during the relaxation trials of the second session, but other measures failed to distinguish between the groups. The group that received FPV feedback revealed a significantly higher level of FPV (relative to baseline) than the group that received no feedback.     

Effects of biofeedback on the discrimination of electrodermal activity

Twenty-four subjects were tested on their ability to discriminate between the presence and absence of negative skin potential responses before and after training to control skin potential. Training consisted of 52 discrete 30-second trials during which subjects were asked either to increase or to inhibit palmar sweating. Subjects in groups N and P were provided with analogue feedback on their skin potential activity. Group N was correctly informed that increases in sweating were indicated by increases in the negativity of skin potential; group P was misinformed that these were indicated by increases in the positivity of skin potential. Subjects in the control (C) group received no feedback. Reliable evidence of discrimination was obtained only in groups N and P, following training. However, reliable evidence of control was obtained only in group N. Thus, training to control skin potential led to an ability to identify afferentation associated with the more common (i.e., negative) skin potential responses, even though biofeedback training appeared unsuccessful in the case of group P. These findings are discussed in the context of "discrimination" or "awareness" accounts of the process of acquiring control of internal response.     

The neuronal electrical responses of the superior cervical ganglion in the rabbit to nociceptive skin stimulation]

The patterns of tonic activity in the neurons of rabbit superior cervical ganglion at rest and during noxious stimulation of the skin were studied using intracellular recording. According to reflex changes in the activity patterns, all neurons studied were classified into three groups. Cardiac rhythmicity is more pronounced in the neurons of the second type than in those of the first type. The magnitude of the cardiac rhythmicity in both types of neurons was reduced after noxious stimulation of the skin. In the third type of neurons the cardiac rhythmicity was absent. In some neurons slow excitatory and inhibitory postsynaptic potentials appeared resulting from skin stimulation.     

Conditioning of skin conductance levels through a combined instrumental-classical conditioning procedure

A paucity of studies and inconsistent results characterize attempts to instrumentally condition tonic electrodermal activity. The present study was conducted to further explore the classical and instrumental conditioning of skin conductance levels (SCLs) through auditory analogue feedback. Fifty undergraduates were randomly assigned to one of five groups of equal size: instrumental conditioning alone, classical conditioning alone, instrumental and classical conditioning combined, and two control groups. The combined training group achieved significantly higher SCLs relative to the group receiving instrumental conditioning alone.     

Effects of attention and slow potential shifts on self-regulation of event-related potentials

Research on the effects of self-regulation of slow potentials (SP) and event-related potentials (ERP) has failed to look at the possible interactions of these two kinds of brain potentials. The present study investigated such interactions by recording both ERP and SP potential changes in an operant ERP conditioning paradigm. Ten subjects participated in two conditions that were designed to differentially manipulate attention to the stimuli. In the operant conditioning task, subjects received auditory feedback as they attempted to increase the ERP amplitude at 180 msec poststimulus (P180), which was elicited by a subpainful shock stimulus to the forearm over 250 trials. In the distraction task, subjects were instructed not to attend to stimuli or feedback tones, but rather received and were tested on reading materials. Attention, as manipulated by these tasks, was not a determinant of changes in ERP amplitude since there were no significant differences in the size of P180 between attention conditions. While no significant change in the mean ERP amplitude occurred, subjects were able to produce ERPs above criterion threshold significantly more often during trials in the conditioning task than in the reading task. Thus, there was evidence of some learning. The difference in wave forms between hit and miss trials indicates a latency shift (with misses having a later ERP peak). This may indicate that latency, rather than, or in addition to, amplitude, is shaped during conditioning procedures. In addition, the CNV that developed between the shock stimulus and the feedback signal during conditioning was significantly larger in amplitude than in the distraction condition. This is taken as evidence of increased attention during conditioning. Since hit trials demonstrated larger contingent negative variation (CNV) amplitudes, production of CNVs may be instrumental in mediating hits. Therefore, attentional mechanisms may play a role in successful ERP self-regulation. No correlations were found involving P180, CNVs, or tonic slow potential shifts. Changes in tonic DC levels showed a suggestive trend between conditions. Although both conditions began with a negative shift, during conditioning the negativity increased, while during distraction the tonic level went to positivity. These trends support the hypothesis that attention and arousal increased during conditioning. The possible reasons for the lack of significant correlations between ERP and tonic or phasic slow potential changes in this paradigm are discussed.     

Determinants of tonic and phasic reactions in transswitching

Forty-eight college students were assigned randomly to four groups in a 2 X 2 factorial arrangement of phasic conditional stimuli (same vs. different) and tonic conditional stimuli (same vs. different) to receive 2 days of classical conditioning with a transswitching procedure. Tonic stimuli were a 5-minute projected white triangle or circle; phasic stimuli were a 5-second red or green square superimposed over the tonic stimuli. There were six tonic stimulus segments each day, separated by 20-second periods of no stimulus, three containing six trials of the phasic stimulus paired with shock and three containing six trials of the phasic stimulus alone, in the counterbalanced order. Tonic responding at the onset of the tonic stimuli or during brief periods following its onset were recorded, along with phasic responses to the phasic stimuli. Responses included magnitude of skin conductance responses, frequency of unelicited skin conductance responses, and tonic heart rate. Both skin conductance measures of responding to the tonic stimuli differentiated significantly between positive and negative tonic segments during Day 2, but only in the group with two different tonic stimuli and one phasic stimulus ("standard" transswitching). This supported the hypothesis that tonic stimulus differentiation would be absent when two different phasic stimuli were present. The heart rate data did not support this hypothesis, showing tonic differentiation in both groups with two tonic stimuli. Phasic differentiation controlled by the different phasic stimuli was observed on Day 1; on Day 2, phasic differentiation was present only in the group with two tonic and one phasic stimuli and the group with one tonic and two phasic stimuli.(ABSTRACT TRUNCATED AT 250 WORDS)     

Common motor mechanisms support body load in serially homologous legs of cockroaches in posture and walking

We studied the mechanisms underlying support of body load in posture and walking in serially homologous legs of cockroaches. Activities of the trochanteral extensor muscle in the front or middle legs were recorded neurographically while animals were videotaped. Body load was increased via magnets attached to the thorax and varied through a coil below the substrate. In posture, tonic firing of the slow trochanteral extensor motoneuron (Ds) in each leg was strongly modulated by changing body load. Rapid load increases produced decreases in body height and sharp increments in extensor firing. The peak of extensor activity more closely approximated the maximum velocity of body displacement than the body position. In walking, extensor bursts in front and middle legs were initiated during swing and continued into the stance phase. Moderate tonic increases in body load elicited similar, specific, phase dependent changes in both legs: extensor firing was not altered in swing but was higher after foot placement in stance. These motor adjustments to load are not anticipatory but apparently depend upon sensory feedback. These data are consistent with previous findings in the hind legs and support the idea that body load is countered by common motor mechanisms in serially homologous legs.     

Conditioning of skin conductance levels through a combined instrumental-classical conditioning procedure

A paucity of studies and inconsistent results characterize attempts to instrumentally condition tonic electrodermal activity. The present study was conducted to further explore the classical and instrumental conditioning of skin conductance levels (SCLs) through auditory analogue feedback. Fifty undergraduates were randomly assigned to one of five groups of equal size: instrumental conditioning alone, classical conditioning alone, instrumental and classical conditioning combined, and two control groups. The combined training group achieved significantly higher SCLs relative to the group receiving instrumental conditioning alone.This study was completed by the first author under the direction of the second author in partial fulfillment of the requirements for the Master of Arts degree.     

Stimulus change dis-habituates operant responding supported by water reinforcers

The present experiment examined whether habituation contributes to within-session decreases in operant responding for water reinforcers. The experiment asked if this responding can be dishabituated, a fundamental property of habituated behavior. During baseline, rats’ lever pressing was reinforced by water on a variable interval 15-s schedule. During experimental conditions, rats responded on the same schedule and a new stimulus was introduced for 5 min at 15, 30 or 45 min into the 60-min session. The new stimulus was extinction, continuous reinforcement or flashing lights in different conditions. Rate of responding primarily decreased within the session during baseline. Introducing a new stimulus sometimes suppressed (extinction, continuous reinforcement) and sometimes increased (flashing lights) responding while it was in effect. The new stimulus increased responding after it ended and before it was presented in the session. The results are incompatible with the idea that non-habituation satiety factors (e.g., cellular hydration and blood volume) contributed to within-session changes in responding. These satiety factors should increase with increases in consumption, decrease with decreases in consumption and remain constant with constant consumption of water. Nevertheless, all stimulus changes increased operant responding for water. These results support the idea that habituation contributes to within-session decreases in responding for water reinforcers.