The ability to control the occurrence of rewarding and punishing events is crucial for our well-being. Two ways to optimize performance are to follow heuristics like Pavlovian biases to approach reward and avoid loss or to rely more on slowly accumulated stimulus–action associations. Although reduced control over outcomes has been linked to suboptimal decision-making in clinical conditions associated with learned helplessness, it is unclear how uncontrollability of the environment is related to the arbitration between different response strategies. This study directly tested whether a behavioral manipulation designed to induce learned helplessness in healthy adults (intermittent loss of control over feedback in a reinforcement learning task; “yoking”) would modulate the magnitude of Pavlovian bias and the neurophysiological signature of cognitive control (frontal midline theta power) in healthy adults. Using statistical analysis and computational modeling of behavioral data and electroencephalographic signals, we found stronger Pavlovian influences and alterations in frontal theta activity in the yoked group. However, these effects were not accompanied by reduced performance in experimental blocks with regained control, indicating that our behavioral manipulation was not potent enough for inducing helplessness and impaired coping ability with task demands. We conclude that the level of contingency between instrumental choices and rewards/punishments modulates Pavlovian bias during value-based decision-making, probably via interfering with the implementation of cognitive control. These findings might have implications for understanding the mechanisms underlying helplessness in various psychiatric conditions.

The ability to control the occurrence of rewarding and punishing events is crucial for our well-being. Two ways to optimize performance are to follow heuristics like Pavlovian biases to approach reward and avoid loss, or to rely more on slowly accumulated stimulus-action associations. Although reduced control over outcomes has been linked to suboptimal decision-making in clinical conditions associated with learned helplessness, it is unclear how uncontrollability of the environment is related to the arbitration between different response strategies.This study directly tested whether a behavioral manipulation designed to induce learned helplessness in healthy adults (intermittent loss of control over feedback in a reinforcement learning task; “yoking”) would modulate the magnitude of Pavlovian bias and the neurophysiological signature of cognitive control (frontal midline theta power) in healthy adults. Using statistical analysis and computational modeling of behavioral data and electroencephalographic signals, we found stronger Pavlovian influences and alterations in frontal theta activity in the yoked group. However, these effects were not accompanied by reduced performance in experimental blocks with regained control, indicating that our behavioral manipulation was not potent enough for inducing helplessness and impaired coping ability with task demands.We conclude that the level of contingency between instrumental choices and rewards/punishments modulates Pavlovian bias during value-based decision-making, probably via interfering with the implementation of cognitive control. These findings might have implications for understanding the mechanisms underlying helplessness in various psychiatric conditions.

Objectives/AimsLearning from experience and making decisions based on integrated environmental feedback is crucial for human functioning and wellbeing. Difficulties in learning and decision-making have been found in several psychiatric conditions. Pavlovian bias, a tendency to approach reward and remain passive in the face of punishment, can be advantageous in some situations, while in others, it can lead to maladaptive decisions and needs to be overcome by cognitive control. It has been suggested that healthy humans rely more heavily on Pavlovian bias when instrumental control over environmental reinforcers is compromised. In our study, we were focusing on the influence of transcranial direct current stimulation (tDCS) on Pavlovian bias during and after an intermittent loss of control over rewards and losses.MethodsIn our pilot study, 19 adults underwent three blocks of an orthogonalized go-nogo reinforcement learning task. Blocks 1 and 3 had a response-feedback contingency of 70–30%, enabling learning via trial-and-error. In the second block, the outcome was independent of the participants’ responses (50%-50% contingency level). Cortical responses of all participants were recorded via EEG. Multi-electrode tDCS targeting the medial prefrontal cortex was administered in a randomised, double-blind placebo-controlled manner.ResultsWe conducted a repeated-measures ANOVA with ‘session’ (PRE x tDCS x POST), ‘valence’ (Win x Avoid) and ‘PB-congruency’ (Pavlovian bias congruent x incongruent) as within-factors, ‘group’ (Active stimulation x Sham) as the between- factor and ‘accuracy’ as the dependent variable. The interaction of ‘session’ and ‘PB- congruency’ with F(2,16)=2.62, p=0.09 were marginally significant, pointing towards slightly enhanced Pavlovian bias in the second block. However, the interaction of ‘session’, ‘PB-congruency’ and ‘group’ was not significant (F(2,16)=0.46, p=0.63). The evaluation of the feedback-related negativity (FRN) in the EEG revealed gradually increasing amplitudes in reward trials in the sham group, whereas we found a trend towards reduced FRN amplitude in the active group with F(2,13)=2.83, p=0.08.ConclusionsOur preliminary data show that a loss of control over feedbacks might increase the effect of Pavlovian bias on the choices of all participants. Although active tDCS seems to attenuate cortical responses during feedback evaluation, this effect is not accompanied by alterations in choice behaviour. Our data collection is still ongoing. The results from the full sample of 50 participants will be analysed by February 2020.

Pavlovian bias is an innate motivational tendency to approach rewards and remain passive in the face of punishment. The relative reliance on Pavlovian valuation has been found to increase when the perceived control over environmental reinforcers is compromised, leading to behavior resembling learned helplessness (LH). In our study, we used a version of an orthogonalized Go-NoGo reinforcement learning task to examine the relative reliance on Pavlovian and instrumental valuation during and after an intermittent loss of control over rewards and losses. Sixty healthy young adults underwent the task and received anodal high-definition transcranial direct current stimulation (HD-tDCS) over the medial prefrontal/ dorsal anterior cingulate cortex in a randomized, double-blind, sham-controlled study. Furthermore, we evaluated changes in cue-locked mid-frontal theta power derived from electroencephalography. We hypothesized that active stimulation would reduce Pavlovian bias during manipulation of outcome controllability, and the effect would be accompanied by stronger mid-frontal theta activity, representing arbitration between choice strategies in favor of instrumental relative to Pavlovian valuation. We found a progressive decrease in Pavlovian bias during and after the loss of control over feedback. Active HD-tDCS counteracted this effect while not affecting the mid-frontal theta signal. The results were at odds with our hypotheses but also with previous findings reporting LH-like patterns during and after the loss of control without brain stimulation. The discrepancy may be related to different protocols for the controllability manipulation. We argue that the subjective evaluation of task controllability is crucial in mediating the balance between Pavlovian and instrumental valuation during reinforcement learning and that the medial prefrontal/dorsal anterior cingulate cortex is a key region in this respect. These findings have implications for understanding the behavioral and neural underpinnings of LH in humans.