A retrospective analysis of the relation between resurgence and renewal of behavior targeted for reduction.

Functional communication training (FCT) is an evidence-based treatment for behavior targeted for reduction that often combines extinction for target responses and arranges functionally equivalent reinforcement for alternative behavior. Long-term effectiveness of FCT can become compromised when transitioning from clinic to nonclinic contexts or thinning reinforcement schedules for appropriate behavior. Such increases in targeted behavior have been conceptualized as renewal and resurgence, respectively. The relation between resurgence and renewal has yet to be reported. Therefore, the present report retrospectively analyzed the relation between renewal and resurgence in data collected when implementing FCT with children diagnosed with developmental disabilities. We found no relation when evaluating all 34 individuals assessed for resurgence and renewal or a subset of individuals exhibiting both resurgence and renewal. These findings suggest that one form of relapse may not be predictive of another form of relapse.

Assessment of the inbred C57BL/6 and outbred CD1 mouse strains using a progressive ratio schedule during development.

Inbred strains have a genetic similarity of at least 98.6% compared to their outbred counterparts. Several studies have shown that inbred C57BL/6 mice and outbred ICR (CD1) mice differ in locomotion, cognitive flexibility, and aggression. However, their performance in operant paradigms is not well understood. A progressive ratio (PR) schedule of reinforcement is a method of quantitative estimation of the incentive state of an animal for a reward by increasing response requirements for reinforcer delivery, which is relevant to assess the breakpoint (amount of response effort an animal is willing to invest for a single unit of reward). This study tested male and female C57BL/6 and CD1 mice with an open field to analyze locomotion. Then, we used conditioning chambers with a PR3 schedule for ten consecutive days (P30-P40). PR performance was measured with the breakpoint, and the mathematical principles of reinforcement (MPR) were used to estimate motivation, impulsivity, and motor skills to manipulate the operandum. We found that CD1 mice showed higher locomotor activity than C57BL/6 independently of sex. CD1 mice had a higher breakpoint. However, male CD1 mice gradually increased breakpoint until the last session. In the MPR model, CD1 mice showed decreased fixed paused parameter (impulsivity) than C57BL/6, independent of sex. Our data suggest that the higher breakpoint in CD1 strain may partially be related to impulsivity. Therefore, the MPR model can help identify factors that affect performances, such as motivation, impulsivity, and motor skills during a PR in adolescent CD1 and C57BL/6 mice. These findings are essential to characterize the differences in the behavioral performance between C57BL/6 and CD1 strains and their potential as animal models.

Resurgence Following Higher or Lower Quality Alternative Reinforcement.

Resurgence is a temporary increase in a previously suppressed target behavior following a worsening in reinforcement conditions. Previous studies have examined how higher rates or magnitudes of alternative reinforcement affect suppression of the target behavior and subsequent resurgence. However, there has been no investigation of the effects of higher versus lower qualities of alternative reinforcement on resurgence. Using a three-phase resurgence preparation with rats, the present experiments examined the effects of an alternative reinforcer that was of higher (Experiment 1) or lower (Experiment 2) quality than the reinforcer that had previously maintained the target behavior. The results of both experiments showed greater reductions in target behavior with a higher quality alternative reinforcer and larger increases in target responding when a higher quality alternative reinforcer was removed. Along with prior findings with higher rates and magnitudes of alternative reinforcement, these findings suggest that variations in reinforcer dimensions that increase the efficacy of alternative reinforcement also tend to increase resurgence when alternative reinforcement is removed. The results are discussed in terms of the resurgence as choice in context model and in terms of potential clinical implications.

The role of stimulus combinations in the repeated assessment of resurgence.

The current study examined the role of stimulus combinations on the repeated assessment of resurgence. Using a within-session resurgence procedure, rats were exposed to different conditions, each with distinct stimulus combinations (AAA, ABA, ABB, ABC and AAB). Two arrangements of stimulus changes were compared: Experiment 1 involved changes in stimulus combinations every five sessions, while Experiment 2 implemented changes every session. Resurgence was observed in both experiments; however, Experiment 2 demonstrated more consistent and repeated resurgence when stimulus combinations changed every session. Notably, the ABA, ABB and ABC conditions showed the highest percentage of sessions in which resurgence was observed. Lastly, the current study extends the application of the within-session resurgence procedure to rats and auditory stimuli, providing a reliable method for assessing resurgence in single subjects under different variable conditions.

An analysis of coordinated responding of pigeons.

Experimental analyses of coordinated responding (i.e., cooperation) have been derived from a procedure described by Skinner (1962) in which reinforcers were delivered to a pair of subjects (a dyad) if both responded within a short interval, thus satisfying a coordination contingency. Although it has been suggested that this contingency enhances rates of temporally coordinated responding, limitations of past experiments have raised questions concerning this conclusion. The present experiments addressed some of these limitations by holding the schedule of reinforcement (Experiment 1: fixed ratio 1; Experiment 2; variable interval 20 s) constant across phases and between dyad members and by varying, in different conditions, the number of response keys (one to three) across which coordination could occur. Greater percentages of coordinated responding occurred under the coordinated-reinforcement phases than under independent-reinforcement phases in most conditions. The one exception during the one-key condition of Experiment 1 appeared to be a consequence of variability introduced by the independent-reinforcement phase procedure. Furthermore, coordination percentages decreased with increasing response options under both schedules. These results confirm and extend the finding that coordination contingencies control higher rates of temporally coordinated responding than independent-reinforcement contingencies do.

A systematic review of enhanced resurgence paradigms.

Following successful treatment in which problem behavior is reduced, it may reemerge as a function of changes in contextual stimuli or the worsening of reinforcement conditions for an alternative response. Although understudied, preliminary research suggests that simultaneous changes in contextual stimuli and reinforcement conditions may represent particularly exigent treatment challenges that create the condition for additive or superadditive relapse. The purpose of the present review was to systematically examine the relapse literature involving simultaneous changes in contextual stimuli and reinforcement conditions in relapse tests and experimental preparations arranged to evaluate their effect on response recovery. We identified 16 empirical articles spanning 27 experiments. Although all experiments included at least one condition that experienced a change in contextual stimuli and worsening of alternative reinforcement conditions, only two experiments included the comparison conditions needed to precisely evaluate additive and superadditive relapse. Our findings establish the preclinical generality of relapse effects associated with simultaneous changes to reinforcement conditions and contextual stimuli across a range of subjects, schedule arrangements, response topographies, reinforcers, and types of contextual changes. We make several recommendations for future research based on our findings from this nascent and clinically relevant subdomain of the relapse literature.

Theoretical note: Quantity and concentration as co-determinants of the reinforcing value of sucrose: A re-analysis of some previously published data.

According to the Multiplicative Hyperbolic Model of reinforcer value (MHM), the overall value of a reinforcer may be defined by the multiplicative combination of a set of hyperbolic functions, each of which defines the impact of a particular feature of the reinforcer (e.g., quantity, immediacy of delivery). A previous experiment found that the relationship between the indifference volumes (qA(50)) of reinforcer A (a 0.4-M sucrose solution) and the fixed volume (qB) of reinforcer B (a 0.2-M sucrose solution: 32 - 256 µl) was consonant with this model. This paper describes a re-analysis of those data in an attempt to identify the nature of the effect of concentration on the two parameters of the size/value hyperbola (asymptote, ε, and sensitivity, Q). Comparison of two versions of the model in which (i) both parameters were free to vary as a function of qB and (ii) only ε was free to vary, showed that the latter model provided a satisfactory account of the data and that the inclusion of Q as an additional free parameter was not justified. Implications for the development of MHM are discussed.

Comparing extinction and contrast effects for operant wheel running and lever pressing on a multiple schedule.

Extinction and positive contrast effects were assessed on a multiple schedule with lever pressing as the operant in one component and wheel running as the operant in the other component. FR 15 schedules produced 15% sucrose reinforcement in each component. Contrast for both operants was generated by placing responding in the alternate component on extinction. Results showed that extinction decreased and contrast increased both lever-pressing and wheel-running rates. However, the magnitude of the changes was greater for lever pressing. Extinction increased and contrast decreased postreinforcement pause (PRP) duration for lever pressing, but for wheel running, extinction decreased PRP duration while contrast did not change PRP duration. Finally, outcomes for lever pressing decreased with extinction and increased with contrast, but for wheel running, outcomes did not change with extinction and increased with contrast. These differences in contrast and extinction effects were explained by an automatic reinforcement effect generated by wheel-running, but not lever pressing. These findings provide further support for an automatic reinforcement effect generated by wheel running.

The sequencing of trials during partial reinforcement affects subsequent extinction.

If a conditioned stimulus or response has been inconsistently ("partially") reinforced, conditioned responding will take longer to extinguish than if responding had been established by consistent ("continuous") reinforcement. This partial reinforcement extinction effect (PREE) is one of the best-known phenomena in associative learning but defies ready explanation by associative models which assume that a partial reinforcement schedule will produce weaker conditioning that should be less resistant to extinction. The most popular explanation of the PREE is that, during partial reinforcement, animals learn that recent nonreinforced (N) trials are associated with subsequent reinforcement (R), and therefore the presence of N trials during extinction serves to promote generalization of conditioning to extinction. According to sequential theory (Capaldi, 1966), animals can encode whole sequences (runs) of N trials and associate their memory of the sequence with subsequent R. The length of these N sequences during conditioning affects how long the animal will continue to respond during extinction. The present experiment used Pavlovian magazine approach conditioning with rats to test two predictions of this theory. Consistent with sequential theory, the PREE was sensitive to the length of the N sequence: conditioning with long sequences (runs of 3-5 N trials) produced a stronger PREE than conditioning with short sequences (runs of 1 or 2) even when the total number of N and R trials was held constant. Surprisingly, there was no PREE among rats trained with the short sequences. Moreover, contrary to the theory's prediction, interrupting the long N sequences with reinforced trials of a different conditioned stimulus did not affect the subsequent PREE. I conclude that uncertainty about reinforcement, rather than the memory of N sequences per se, is a key factor in the development of the PREE. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The multiple-stimulus-without-replacement preference assessment tool and its predictive validity.

This study demonstrates the use of two web-based programs, one to identify video preferences and the other to assess their reinforcing effects. We used the Multiple-Stimulus-Without-Replacement Preference Assessment Tool (MSWO PAT) to identify the video preference hierarchies of seven participants, ages 4-11 years old. We then used a customized reinforcer assessment program that arranged a concurrent-chains preparation with programmed conjugate schedules of reinforcement. Button presses emitted by participants modulated the quality (volume and opacity) of selected videos on a moment-to-moment basis, allowing us to identify the reinforcing effects of the videos in little time. The results showed that the preference assessment had predictive value for five of seven participants. We discuss the MSWO PAT, parameters that may affect the identification of preferences and the use of conjugate schedules to identify reinforcers.

Acquisition of cocaine reinforcement using fixed-ratio and concurrent choice schedules in socially housed female and male monkeys.

RATIONALE: Previous studies in socially housed monkeys examining acquisition of cocaine self-administration under fixed-ratio (FR) schedules of reinforcement found that subordinate males and dominant females were more vulnerable than their counterparts. OBJECTIVES: The present studies extended these findings in two ways: (1) to replicate the earlier study, in which female monkeys were studied after a relatively short period of social housing (~ 3 months) using cocaine-naïve female monkeys (n = 9; 4 dominant and 5 subordinate) living in well-established social groups (~ 18 months); and (2) in male monkeys (n = 3/social rank), we studied cocaine acquisition under a concurrent schedule, with an alternative, non-drug reinforcer available. RESULTS: In contrast to earlier findings, subordinate female monkeys acquired cocaine reinforcement (i.e., > saline reinforcement) at significantly lower cocaine doses compared with dominant monkeys. In the socially housed males, no dominant monkey acquired a cocaine preference (i.e., > 80% cocaine choice) over food, while two of three subordinate monkeys acquired cocaine reinforcement. In monkeys that did not acquire, the conditions were changed to an FR schedule with only cocaine available and after acquisition, returned to the concurrent schedule. In all monkeys, high doses of cocaine were chosen over food reinforcement. CONCLUSIONS: The behavioral data in females suggests that duration of social enrichment and stress can differentially impact vulnerability to cocaine reinforcement. The findings in socially housed male monkeys, using concurrent food vs. cocaine choice schedules of reinforcement, confirmed earlier social-rank differences using an FR schedule and showed that vulnerability could be modified by exposure to cocaine.

Effect of instructions on the microstructure of human schedule performance.

Three experiments examined the effect of instructions on human free-operant performance on random ratio (RR) and random interval (RI) schedules. Both rates of responding, and the microstructure of behavior, were explored to determine whether bout-initiation and within-bout responding may be controlled by different processes. The results demonstrated that responding in acquisition (Experiments 1 and 2) and extinction (Experiment 3) was impacted in line with given instructions. During acquisition, rates were higher on RR compared to RI for accurate and minimal instructions. During extinction, rates decreased when there were minimal instructions. However, instructions had a greater impact on within-bout responding, than they did on bout-initiation responding. Overall rates of responding, and within-bout rates, varied in line with the nature of the instructions, but bout-initiation responding did not (Experiments 1 and 2). Resistance to extinction was increased by instructions in terms of overall responding and within-bout rates, but not in terms of bout-initiation rates (Experiment 3). These data are consistent with the hypothesis that bout-initiation responding may be less impacted by instructions than within-bout responding, speculatively, the former is stimulus-driven, automatic/habitual, and less accessible to conscious processing. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The effects of gonadal hormones on heroin Self-Administration in male gonadectomized rats.

RATIONALE: Previous studies have shown that gonadal hormones influence opioid self-administration in female rodents, but very few studies have examined these effects in male rodents. OBJECTIVES: The purpose of this study was to examine the effects of chronic hormone treatment on intravenous heroin self-administration in gonadectomized male rats using both physiological and supraphysiological doses of testosterone, estradiol, or progesterone. METHODS: Gonadectomized male rats were surgically implanted with intravenous catheters and trained to self-administer heroin on a fixed ratio (FR1) schedule of reinforcement. Using a between-subjects design, rats were treated daily with testosterone (0.175 or 1.75 mg, sc), estradiol (0.0005 or 0.005 mg, sc), progesterone, (0.0125 or 0.125 mg, sc), or their vehicles. After 14 days of chronic treatment, a dose-effect curve was determined for heroin (0.0003-0.03 mg/kg/infusion) over the course of one week. RESULTS: Neither testosterone nor estradiol altered responding maintained by heroin. In contrast, the high dose of progesterone (0.125 mg) reduced responding maintained by all doses of heroin to saline-control levels. This dose of progesterone did not reduce responding maintained by food on a progressive ratio schedule in either food-restricted or food-sated rats. CONCLUSIONS: These data indicate that exogenous progesterone or a pharmacologically active metabolite selectively decreases heroin intake in male rodents, which may have therapeutic implications for men with opioid use disorder.

Time, uncertainty, and suboptimal choice.

Under certain conditions, pigeons prefer information about whether food will be forthcoming at the end of an interval to a higher chance of obtaining the food. In the typical protocol, choosing one option (Informative) is followed by one of two 10-s long terminal-link stimuli: SG always ending in food or SR never ending in food, with SG occurring only 20% of the trials. The other option (Non-informative) is also followed by one of two 10-s long terminal-link stimuli: SB or SY, both ending in food 50% of the trials. Although the Informative option yields food with a lower probability than the Non-informative (0.2 vs. 0.5), pigeons prefer it. To determine whether such preference occurs because SG and SR disambiguate the trial outcome immediately upon choice, we delayed the moment the disambiguation took place in two experiments. In Experiment 1, when the Informative option was chosen, SG always ensued for t seconds of the terminal-link, and then the standard contingencies followed. Experiment 2 was similar, except that SR always ensued for t seconds. Across conditions, t varied from 0 to 10 s. In both experiments, preference for the Informative option decreased with t, but the effect was stronger in Experiment 1. We discuss the implication of these findings for functional and mechanistic models of suboptimal choice.

Relative preference for distinct reinforcers maintaining destructive behavior.

The literature offers few recommendations for sequencing exposure to treatment conditions with individuals with multiply maintained destructive behavior. Identifying relative preference for the functional reinforcers maintaining destructive behavior may be one means of guiding that decision. The present study presents a preliminary attempt at developing a robust relative preference and reinforcer assessment for individuals with multiply maintained destructive behavior. Guided and free-choice trials were implemented in which participants chose between two multiple-schedule arrangements, each of which programmed signaled periods of isolated reinforcer availability and unavailability. Consistent participant choice and responding during free-choice trials was then used to thin the corresponding schedule of reinforcement. The results demonstrated a strong preference for one of the two functional reinforcers for all four participants, yet preferences differed across participants and were not well predicted by responding in prior analyses.

Multiple schedules of conjugate reinforcement and extinction: A translational model for assessing automatically reinforced behavior.

This study evaluated the extent to which a conjugate reinforcement schedule (CONJ) involving a contingency between pedaling a stationary bike and viewing a preferred movie could serve as a translational preparation for the analysis of automatically reinforced behavior. In part, researchers examined whether providing participants with either an accurate or an inaccurate rule about the extinction (EXT) component of a multiple schedule (MULT) contributed to the development of control by the MULT (CONJ EXT) schedule. Results show schedule control emerged for four of five participants who received the accurate rule and none of the five participants who received the inaccurate rule. In addition, participants who received accurate rules typically increased pedaling during CONJ components that followed two consecutive EXT components, suggesting that they experienced deprivation for audio and visual stimulation generated by pedaling. These preliminary findings suggest that researchers could use this translational preparation to identify matched interventions for some automatically reinforced behavior.

Further observations on the reinforcing value of sucrose solutions: Interaction between quantity and concentration.

According to the Multiplicative Hyperbolic Model of reinforcer value (MHM), the value of a reinforcer is an increasing hyperbolic function of its size. In addition it is generally accepted that in the case of soluble reinforcers such as sucrose, value is an increasing function of molar concentration. The present experiment examined the interaction between size and concentration on the effectiveness of sucrose reinforcers in an operant choice paradigm. Rats were trained under an adjusting-magnitude schedule in which a response on lever B delivered a fixed volume of a sucrose solution, while a response on lever A delivered a 0.8-M sucrose solution, the volume of which, qA, was adjusted according to the rats' choices. When B was preferred in a given block of trials, qA was increased in the following block; when A was preferred, qA was reduced in the following block. The concentration and volume of B (cB, qB) were varied across six phases of the experiment and the corresponding indifference magnitudes of A (qA(50)) were measured. Log qA(50) increased and qB/qA(50) declined as approximately linear functions of log cB, consistent with the supposition that reinforcer value was determined by multiplicative combination of hyperbolic expressions representing concentration and volume.

The ascending limb of the cocaine unit dose-response function in rats as an experimental artifact.

The cocaine unit dose-response function is an inverted U with the ascending and descending limbs representing the positive and rate limiting cocaine effects, respectively. Higher fixed ratio (FR) schedules and/or time-out periods make the ascending limb more prominent. Alternatively, a pharmacokinetic/pharmacodynamic interaction theory demonstrates that cocaine-induced lever pressing occurs only when cocaine levels are within a range termed the compulsion zone. The inter-injection intervals of self-administration increase with cocaine unit dose because of the longer time required to eliminate higher doses. However, this theory has not been applied to high FR schedules. Rats acquired cocaine self-administration on a FR1 schedule and then were changed to sessions that started with both FR1 and then FR50 over a range of unit doses with a set number of self-administrations allowed for each dose. On FR1, rats completed the maximum number of injections at all but the lowest unit dose. In contrast, on FR50 the proportion of the permitted injections increased as a function of unit dose. However, this ascending limb was the result of averaging data from sessions where rats completed or failed to complete the allowed number of injections. Rats completed all injections when cocaine levels were maintained in the compulsion zone. The FR50 schedule and low unit doses decreased this probability of maintaining cocaine levels in the compulsion zone when the rate of cocaine elimination exceeded the rate of cocaine input during the time required to complete the 50 presses. It is concluded that the ascending limb is an experimental artifact and that the entire dose-response function and the FR50-induced increase in inter-injection intervals are explained in terms of the compulsion zone theory of cocaine self-administration behavior.

Acute but not long-lasting antidepressant-like effect of psilocybin in differential reinforcement of low-rate 72 schedule in rats.

BACKGROUND: In clinical studies, psychedelics including psilocybin and D-lysergic acid diethylamide (LSD) demonstrate rapid and persistent antidepressant effects. Since the effective treatment with psychedelics is usually provided with psychotherapy, it is debatable whether their prolonged efficacy can be observed in infrahuman species. Preclinical reports on psychedelics' effects most often address their acute actions, and different tests and models provide inconsistent results. The goal of this study was to examine whether the treatment with psilocybin and/or LSD would demonstrate immediate and/or sustained antidepressant-like effects in the differential reinforcement of low-rate responding (DRL) schedule in rats. In contrast to the antidepressant screening tools, the DRL 72s test is known to detect antidepressants with high predictive validity as it differentiates clinically effective antidepressants from other psychoactive drugs in non-stressed animals. METHODS: Adult male Sprague Dawley rats were injected over three consecutive days with psilocybin (1 mg/kg), LSD (0.08 mg/kg), or saline and then tested in DRL 72s for the following 4 weeks. RESULTS: Treatment with psilocybin but not LSD demonstrated an immediate antidepressant-like effect, manifested as an increased number of reinforced presses and response efficiency. By contrast, neither of the drugs showed a long-term (up to 4 weeks following administration) antidepressant-like effect. CONCLUSIONS: Using DRL 72s schedule of reinforcement, we demonstrated the acute antidepressant-like effect of psilocybin but not of LSD, and failed to detect their persistent antidepressant-like efficacy. The present study suggests that the detection of long-lasting antidepressant-like activity in rats could be challenging and may require entirely novel behavioral methods.

Translational evaluation of on/off alternative reinforcement cycling.

Cycling between the availability and unavailability of reinforcement for alternative responding has successfully reduced resurgence in basic laboratory evaluations, but this approach represents a marked departure from current standards of care when treating problem behavior, warranting careful translation before its use clinically. Therefore, with extinction arranged for target responding across groups in Phase 2, we evaluated the effects of cycling between the availability and unavailability of differential reinforcement of alternative behavior (DRA) using a computer-based task with adult humans recruited through Amazon MTurk. Two control groups experienced constant DRA in Phase 2, with one group experiencing a dense DRA schedule and another group experiencing a lean DRA schedule. The cycling DRA group tended to show greater reductions in target responding and improved discrimination in Phase 2 and less target responding across Phases 2 and 3 than the lean DRA and dense DRA groups. These preliminary findings suggest that on/off DRA cycling procedures may produce more desirable treatment outcomes than constant DRA without producing negative side effects; however, further research is needed to confirm these possibilities.