Assessing the role of alternative response rates and reinforcer rates in resistance to extinction of target responding when combining stimuli

Studies of behavioral momentum reveal that reinforcing an alternative response in the presence of a target response reduces the rate of target responding but increases its persistence, relative to training the target response on its own. Because of the parallels between these studies and differential‐reinforcement techniques to reduce problem behavior in clinical settings, alternative techniques to reduce problem behavior without enhancing its persistence are being explored. One potential solution is to train an alternative response in a separate stimulus context from problem behavior before combining the alternative stimulus with the target stimulus. The present study assessed how differences in reinforcement contingencies and rate for alternative responding influenced resistance to extinction of target responding when combining alternative and target stimuli in pigeons. Across three experiments, alternative stimuli signaling a response–reinforcer dependency and greater reinforcer rates more effectively decreased the persistence of target responding when combining alternative and target stimuli within the same extinction tests, but not when compared across separate extinction tests. Overall, these findings reveal that differences in competition between alternative and target responding produced by contingencies of alternative reinforcement could influence the effectiveness of treating problem behavior through combining stimulus contexts.     

预期错误在复合恐惧记忆提取消退中的作用

基于记忆再巩固理论的提取消退范式被证明是一种有效和颇有前景的消除不良记忆的方法。本研究将预期错误(Prediction Error, PE)应用于提取消退范式中, 采用多感官复合刺激模型(声音 + 图片)作为条件刺激, 以皮电反应作为恐惧反应指标, 考察在提取阶段不同的预期错误设置(无PE、单个负性PE、单个正性PE和多重PE)对条件性恐惧记忆提取消退效果有何差异。结果表明：无PE组和多重PE组出现了恐惧的自发恢复和重建效应, 而负性PE组和正性PE组均没有出现恐惧的自发恢复和重建效应。说明了在对复合恐惧记忆进行提取消退时, 提取阶段适当的PE才能使记忆进入再巩固过程, 随后传统消退达到抑制恐惧返回效果, 提取阶段没有PE或PE量过多都不能达到恐惧消退效果。     

焦虑易感群体焦虑识别与消退中催产素的作用

如何准确识别并缓解焦虑易感群体的焦虑情绪具有重要的社会意义和应用价值。目前焦虑识别与消退的研究缺乏客观和直接的手段,而且在作用机制上也不清晰。本项目以催产素在高依恋焦虑个体焦虑识别与消退中的作用机制为主要研究内容,创造性地将焦虑识别与消退整合在催产素的研究框架内,从生理测量和药物干预的视角为焦虑识别和消退提供新的研究思路。研究成果对于理解焦虑反应中的神经荷尔蒙机制具有重要科学意义,也为高依恋焦虑群体的焦虑评估和干预提供了新的路径参考,对维护和提升个体的心理健康具有重要价值。     

睡眠对恐惧学习的影响及其认知神经机制

睡眠问题可能会诱发恐惧相关情绪障碍(焦虑、创伤性应激障碍、恐怖症等),研究睡眠影响恐惧学习的认知神经机制,有助于增强对恐惧相关情绪障碍的预测、诊断和治疗。以往研究表明睡眠剥夺影响恐惧习得和消退主要是通过抑制vmPFC活动,阻碍其与杏仁核的功能连接,从而导致恐惧习得增强或是消退学习受损。进一步研究发现睡眠不同阶段对恐惧学习相关脑区有独特的影响:剥夺(缺乏)快速眼动睡眠会抑制vmPFC活动、增强杏仁核、海马激活,导致恐惧习得增强,消退学习受损,此外边缘皮层的功能连接减少破坏了记忆巩固(恐惧记忆和消退记忆);而慢波睡眠主要与海马变化有关,慢波睡眠期间进行目标记忆重激活可促进恐惧消退学习。未来研究需要增加睡眠影响恐惧泛化的神经机制研究、及昼夜节律中断对恐惧消退的影响,以及关注动物睡眠研究向人类睡眠研究转化中存在的问题。     

Instrumental conditioning of aggressive behavior in rats

A method has been developed for bringing an aggressive response under stimulus control. It was found that the number of conditioned aggyessive responses was maximal when low-weight target rats were used. The latencies of the conditioned responses toward target animals of 124 gm were significantly lower than those toward animals of 221 and 284 gm. The application of an extinction procedure on the conditioned aggressive response substantially increased the total number of emitted aggressive responses.     

“Other” behavior and the DRO: The roles of extinction and reinforcement

Jessel et al. (2015) provided some evidence to suggest that “other” behavior is strengthened in the differential reinforcement of other behavior (DRO). The present study is a systematic replication of the Jessel et al. procedures. The effects of DRO and extinction on target responding, target-other responding (a response with an established history of reinforcement), and nontarget-other responding emitted by children with intellectual and developmental disabilities and children with no known diagnoses were compared. Other behavior increased in at least one DRO condition for each participant, suggesting that other behavior increases when using DRO, at least initially. Under extinction, target responding and target-other responding decreased to low rates for three of the five participants; however, rates of nontarget-other responding were elevated compared to the DRO condition. These results suggest that increased rates of target-other responding and nontarget-other responding during the DRO condition may be a result of extinction-induced variability.     

The role of adventitious reinforcement during differential reinforcement of other behavior: A systematic replication

Differential reinforcement of other behavior (DRO) is commonly used to decrease problem behavior by presenting reinforcers contingent upon the absence of a target response. Although it is well demonstrated that DROs decrease response rates, the processes producing these decreases are not well understood. The present study systematically replicated previous research assessing whether adventitious reinforcement of alternative behavior contributes to the effectiveness of DRO. We presented university students with two options on a computer and reinforced target responding on a variable-ratio schedule. Next, we compared decreases in target-response rates and any increases in alternative responding during DRO schedules versus yoked variable-time schedules or extinction probes. DRO schedules resulted in the lowest target-response rate and highest alternative-response rate. These findings generally provide some support for the adventitious reinforcement of “other” behavior.     

An experimental analysis of the extinction-induced response burst

The occurrence, time course, and repeatability of response rate increases following the onset of extinction, the extinction burst, were studied in three experiments. Nine pigeons were exposed to at least 5 cycles of 5-session blocks of conditioning followed by 8-session blocks of extinction. In different experiments, conditioning sessions either were a fixed-ratio (FR) or variable-ratio (VR) schedule, and transitions from the last conditioning session in each cycle to the first extinction session were conducted between or within sessions. A single response rate increase occurred when overall response rates were considered. Restricting analyses to the first minute of extinction sessions sometimes revealed increases in response rates, although this finding was inconsistent. The frequency and magnitude of these increases differed across exposures to extinction both across and within pigeons. Additionally, how responding during extinction was measured (i.e., the level of analysis) influenced whether increases above baseline levels were observed. These results suggest that the extinction burst may be influenced by the manner of transition to extinction and the way in which early extinction responding is measured. Under the best conditions, the extinction burst does not appear to be a ubiquitous effect of extinction.     

Learning strategies during fear conditioning

This paper describes a model of fear learning, in which subjects have an option of behavioral responses to impending social defeat. The model generates two types of learning: social avoidance and classical conditioning, dependent upon (1) escape from or (2) social subordination to an aggressor. We hypothesized that social stress provides the impetus as well as the necessary information to stimulate dichotomous goal-oriented learning. Specialized tanks were constructed to subject rainbow trout to a conditioning paradigm where the conditioned stimulus (CS) is cessation of tank water flow (water off) and the unconditioned stimulus (US) is social aggression from a larger conspecific. Following seven daily CS/US pairings, approximately half of the test fish learned to consistently escape the aggression to a neutral chamber through a small escape hole available only during the interaction. The learning curve for escaping fish was dramatic, with an 1100% improvement in escape time over 7 days. Fish that did not escape exhibited a 400% increase in plasma cortisol and altered brain monoamine response to presentation of the CS alone. Elevated plasma cortisol levels represent classical fear conditioning in non-escaping fish, while a lack of fear conditioning and a decreased latency to escape over the training period in escapers indicates learned escape.     

RESURGENCE OF INFANT CAREGIVING RESPONSES

Two experiments were conducted to identify the conditions likely to produce resurgence among adult human participants. The preparation was a simulated caregiving context, wherein a recorded infant cry sounded and was terminated contingent upon targeted caregiving responses. Results of Experiment 1 demonstrated resurgence with human participants in this negative reinforcement preparation. Results of Experiment 2 showed that responses with a longer history of reinforcement showed a stronger resurgence effect relative to responses with a shorter and more recent history of reinforcement. These results show that the resurgence phenomenon occurs across populations and types of reinforcers. Additionally, results indicate that length of reinforcement history is a variable that may affect the magnitude of resurgence.