Anodal tDCS over the medial prefrontal cortex enhances behavioral adaptation after punishments during reversal learning through increased updating of unchosen choice options

Abstract

The medial prefrontal cortex (mPFC) is thought to be central for flexible behavioral adaptation. However, the causal relationship between mPFC activity and this behavior is incompletely understood. We investigated whether transcranial direct current stimulation (tDCS) over the mPFC alters flexible behavioral adaptation during reward-based decision-making, targeting MNI-coordinate X = −8, Y = 62, Z = 12, which has previously been associated with impaired behavioral adaptation in alcohol-dependent patients. Healthy human participants (n = 61) received either anodal (n = 30) or cathodal (n = 31) tDCS versus sham tDCS while performing a reversal learning task. To assess the mechanisms of reinforcement learning (RL) underlying our behavioral observations, we applied computational models that varied with respect to the updating of the unchosen choice option. We observed that anodal stimulation over the mPFC induced increased choice switching after punishments compared with sham stimulation, whereas cathodal stimulation showed no effect on participants’ behavior compared with sham stimulation. RL revealed increased updating of the unchosen choice option under anodal as compared with sham stimulation, which accounted well for the increased tendency to switch after punishments. Our findings provide a potential model for tDCS-interventions in conditions related to flexible behavioral adaptation, such as addiction.

Modulating hierarchical learning by high-definition transcranial alternating current stimulation at theta frequency

“…This suggests that theta stimulation does not promote adaptive learning, but makes learners more inclined to faster learning. This matches previous findings about frontal neuromodulation in probabilistic reversal learning (Wischnewski et al 2016;Borwick et al 2020;Panitz et al 2022), which demonstrated that neuromodulation promotes faster learning to volatile environment. Our study supplements these earlier results by demonstrating that faster learning reduces task performance in the stable environment.…”

Transcranial direct current stimulation impairs updating of avoidance-based associative learning

“…For example, transcranial direct current stimulation (tDCS) – a type of non-invasive neuromodulation that alters intrinsic neuronal activity using a relatively weak but constant electrical current ( Nitsche et al, 2008 ) – has been found to facilitate implicit learning using a probabilistic classification learning task ( Kincses et al, 2004 ). Additionally, tDCS aimed to inhibit ventrolateral prefrontal cortex functioning was associated with more errors during reversal learning as expected ( Albein-Urios et al, 2019 ) whereas tDCS aimed to excite the medial prefrontal cortex led to increased choice shifting following punishments during reversal learning ( Panitz et al, 2022 ). However, in these prior experiments, context was not manipulated and, as we highlighted above, context affects flexible updating and renewal of previously learned associations, which is relevant when the goal of such research is to contribute to the development of novel treatments for fear-based disorders.…”