Classical conditioning and extinction of human systolic blood pressure

Fifty-five male and female undergraduates underwent 3 sessions of conditioning and one of extinction. Shock (UCS) occurred intermittently during light-on (CS+) and never in light-off (CS-). Results showed that (1) pressure in CS+ was significantly higher than CS-throughout all sessions; (2) within session adaptation was significantly retarded while incoming pressure levels did not adapt across sessions; (3) conditioned effects persisted 6 months after the last shock session; (4) verbal information as to non-appearance of shock significantly dropped pressure levels and reduced the discriminative light effect; (5) the post-shock unconditioned pressure response was a peak rise at 52 seconds, then a decrease which stabilized to the pre-shock level at 2 minutes. Pavlovian control of blood pressure was demonstrated and the present methodology offers an explicit procedure for further laboratory exploration.     

Classical discrimination conditioning of the rabbit's eyelid response using pontine stimulation as a conditioned stimulus

Classical discrimination conditioning of the nictitating membrane/eyelid response was performed on seven rabbits using stimulation of the pontine nuclei or middle cerebellar peduncle as the conditioned stimulus (CS) and an air puff as the unconditioned stimulus (US). The rabbits learned to discriminate between a CS paired with a US and delivered to one pontine nucleus (the CS+) and a CS presented alone and delivered to the contralateral pontine nucleus (the CS-). Subsequent reversal of the discrimination was also achieved when the CS+ and CS- stimulation sites were interchanged. The results are interpreted as support for the idea that essential plasticity for classical eyelid conditioning occurs efferent to the pontine nuclei, possibly in regions of the cerebellum.     

Classical conditioning of blood pressure inMacaca mulatta with cardiac rate controlled

The interaction of heart rate and blood pressure responses was studied in four male rhesus monkeys (M. mulatta) during classical delay conditioning and extinction. During initial conditioning sessions, heart rate was held constant by means of an external cardiac pacemaker; in follow-up conditioning sessions, the heart was free of constraint. Observations were made after these conditioning sessions, (a) during several sessions given over to continued training while different pacing rates were in effect; (b) during a series of extinction sessions in which the heart was paced and unpaced; and, (c) when a heart rate CR was simulated by manipulation of the pacer with no conditioned or unconditioned stimuli present. Throughout all sessions, systolic and diastolic pressures were measured at each heart beat. It was found that blood pressure conditioning was largely unaffected when heart rate changes were prevented during acquisition. Extinction of blood pressure responses was also seen to proceed relatively unimpeded when the heart was paced at a fixed frequency. During the postacquisition conditioning sessions, the several different pacing rates that were tested did not produce any significant differential effects in the blood pressure CRs. Simulated heart rate CRs were accompanied by small changes in pressures, sometimes opposite in direction from the pressure CRs observed during unpaced conditioning trials.     

A minicomputer program for stimulus control and analog data for discrete trial paradigms in biological preparations: Classical conditioning

The application of computer technology to classical conditioning requires: control software that will repeatedly generate stimulus events, and analog-to-digital (A/D) recording capabilities for the resolution of analog data from phasic response systems (e.g., nictitating membrane extension, leg flexion). An earlier software package implemented on a 4K PDP-8/E (Millenson, Kehoe, Tait, & Gormezano, 1973) successfully met these requirements. However, the program’s capabilities were restricted to the presentation of only two unique stimuli with a maximum of 4 sec duration, and data reduction in only uniphasic response systems. The present program, employing the same hardware, relaxed these previous constraints and extended the range of data analysis through the revamping of the interactive assembler, operating system, and on-line data processing routines.     

Operant conditioning of human anal sphincter pressure

Anal sphincter pressure in a 13-yr-old encopretic boy was modified by reinforcing increases in pressure exerted on a fluid-filled balloon inserted into the rectum. It was found that pressure changes were a function of the reinforcement schedule and that baseline levels (resting pressure) during extinction conditions tended to increase throughout the experiment.     

Classical eyeblink conditioning: Clinical models and applications

In this paper, we argue that the main reason that classical eyeblink conditioning has proven so useful when applied to clinical situations, is that a great deal of information is known about the behavioral and neural correlates of this form of associative learning. Presented here is a summary of three lines of research that have used classical eyeblink conditioning to study three different clinical conditions; autism, fetal alcohol syndrome, and obsessive-compulsive disorder. While seemingly very different clinical conditions, classical eyeblink conditioning has proven very useful for advancing our understanding of these clinical pathologies and the neural conditions that may underlie them.     

Human evaluative conditioning: Order of stimulus presentation

In an experiment designed to demonstrate evaluative conditioning, subjects were shown 48 pictures of sculptures that they rated on a scale with 21 categories (?10 to +10). Then, the two most liked pictures (L) were paired with pictures from the categories ?1, 0, or +1 (N). In contrast to prior experiments, subjects were given either forward conditioning (N-L) or backward conditioning (L-N) trials but not both. Four other neutral stimuli were paired with each other (N-N) and acted as control stimulus pairs. After conditioning, the stimuli were rated a second time. There was a statistically significant difference in evaluative ratings showing a change of the evaluative tone of the previously neutral stimuli in a positive direction only after forward conditioning. This finding is inconsistent with results of prior experiments and challenges the assumption of Martin and Levey (1987) that evaluative conditioning is different from human classical conditioning.     

Trial and intertrial durations in Pavlovian conditioning: issues of learning and performance

Four experiments assessed the effects of trial (T) and intertrial (I) durations on magazine approach behavior in rats. In Experiments 1 and 2, different groups of animals were conditioned with various combinations of I and T durations. The rate of acquisition, in terms of the number of trials required to reach various acquisition criteria, generally was faster in groups trained with large I:T ratios. There also were differences in rate of acquisition and terminal response rates between groups trained with identical I:T ratios but with different absolute I and T durations. Differences evident at the end of conditioning persisted during a common test with various combinations of I and T durations. Experiments 3 and 4 provided a more specific test of the predictions of 2 general classes of theories and found results that were consistent with those theories that characterize group differences as indicative of differences in learning, rather than in performance.     

The distribution of fixation durations during reading: effects of stimulus quality

Participants' eye movements were recorded as they read single sentences presented normally, presented entirely in faint text, or presented normally except for a single faint word. Fixations were longer when the entire sentence was faint than when the sentence was presented normally. In addition, fixations were much longer on a single faint word embedded in normal text, compared to when the entire sentence was faint. The primary aim of the study was to examine the influence of stimulus quality on the distribution of fixation durations. Ex-Gaussian fitting revealed that stimulus quality affected the mean of the Normal component, but in contrast to results from single-word tasks (Plourde & Besner, 1997), stimulus quality did not affect the exponential component, regardless of whether one or all words were faint. The results also contrast with the finding (Staub, White, Drieghe, Hollway, & Rayner, 2010) that the word frequency effect on fixation durations is an effect on both of the critical distributional parameters. These findings are argued to have implications for the interpretation of the role of stimulus quality in word recognition, and for models of eye movement control in reading.     

Classical conditioning of human ‘evaluative’ responses

Human behaviour includes an important component which may conveniently be called evaluative. Using postcard reproductions as stimulus materials, 10 volunteer subjects selected the two pictures most liked and the two most disliked. These were then used as UCSs with appropriate controls from the neutral category. The conditioning hypothesis—that a neutral stimulus followed by a positively or negatively valued stimulus will acquire the evaluative weight of the second stimulus—was supported at a highly statistically significant level. The effect of negative evaluation was demonstrably stronger than that for positive evaluation, a result consistent with our knowledge of aversive conditioning. The possibility is discussed that evaluation of the UCS by the subject, shown to be a sufficient condition for learning, may also be the only necessary condition. This would imply a model of conditioning based on affective evaluation rather than on response production.     

Classical conditioning and pain: Conditioned analgesia and hyperalgesia

This article reviews situations in which stimuli produce an increase or a decrease in nociceptive responses through basic associative processes and provides an associative account of such changes. Specifically, the literature suggests that cues associated with stress can produce conditioned analgesia or conditioned hyperalgesia, depending on the properties of the conditioned stimulus (e.g., contextual cues and audiovisual cues vs. gustatory and olfactory cues, respectively) and the proprieties of the unconditioned stimulus (e.g., appetitive, aversive, or analgesic, respectively). When such cues are associated with reducers of exogenous pain (e.g., opiates), they typically increase sensitivity to pain. Overall, the evidence concerning conditioned stress-induced analgesia, conditioned hyperalagesia, conditioned tolerance to morphine, and conditioned reduction of morphine analgesia suggests that selective associations between stimuli underlie changes in pain sensitivity.     

Avoidance conditioning as a function of appetitive stimulus pretraining: Response and stimulus transfer effects

Pretrained appetitive discriminative stimuli were used as warning signals in subsequent avoidance learning. In Expt 1 identical responses were required in pretraining and in avoidance learning. An appetitive S+ facilitated avoidance learning in rats in comparison to S? or a stimulus previously uncorrelated with food. In Expt 2, the type of response in pretraining and in avoidance learning was varied. Groups with homogeneous responses in the two situations replicated Expt 1 results, whereas groups with different responses in pretraining and avoidance learning failed to show an advantage when S+ served as warning; in the heterogeneous response groups, S? was as effective as S+. Inhibitory factors in the heterogeneous groups were discussed as an explanation for these results.     

Conditioned response-contingent delays of the unconditioned stimulus in human aversive conditioning.

Four groups of subjects were given either 0. 100, 500, or 1,000 msec delays of the unconditioned stimulus (UCS) contingent upon the occurrence of a conditioned response (CR) and were given a UCS 515 msec after conditioned stimulus (CS) onset when a CR did not occur. A fifth group received standard classical conditioning trials with an interstimulus interval of 515 msec. Overall performance decreased as CR-contingent UCS delay increased, with the classical conditioning group approximating the performance of the group receiving the 100-msec delay. The data were analyzed with the two-phase model of conditioning and the following results were obtained: The duration of Phase 1 of the model increased with contingent delay; operator limits associated with CR trials or with combined CR-CR (CR absent) trials decreased as a function of delay; and operator limits associated exclusively with CR trials were unaffected by the delay. Subjects receiving a contingent delay of 0 msec gave the shortest latency responses and exhibited reliable latency decreases across trials, suggesting an attempt to "beat" the UCS. The results were interpreted as contrary to what would be expected from low-of-effect theories which postulate that reinforcement results from a CR-UCS interaction, although they could be subsumed under a drive or an associative strength theory in which the aversive, or CR-supportive, strength of the UCS is assumed to be negatively correlated with contingent UCS delay.