Transcranial Stimulation over Frontopolar Cortex Elucidates the Choice Attributes and Neural Mechanisms Used to Resolve Exploration-Exploitation Trade-Offs.

Optimal behavior requires striking a balance between exploiting tried-and-true options or exploring new possibilities. Neuroimaging studies have identified different brain regions in humans where neural activity is correlated with exploratory or exploitative behavior, but it is unclear whether this activity directly implements these choices or simply reflects a byproduct of the behavior. Moreover, it remains unknown whether arbitrating between exploration and exploitation can be influenced with exogenous methods, such as brain stimulation. In our study, we addressed these questions by selectively upregulating and downregulating neuronal excitability with anodal or cathodal transcranial direct current stimulation over right frontopolar cortex during a reward-learning task. This caused participants to make slower, more exploratory or faster, more exploitative decisions, respectively. Bayesian computational modeling revealed that stimulation affected how much participants took both expected and obtained rewards into account when choosing to exploit or explore: Cathodal stimulation resulted in an increased focus on the option expected to yield the highest payout, whereas anodal stimulation led to choices that were less influenced by anticipated payoff magnitudes and were more driven by recent negative reward prediction errors. These findings suggest that exploration is triggered by a neural mechanism that is sensitive to prior less-than-expected choice outcomes and thus pushes people to seek out alternative courses of action. Together, our findings establish a parsimonious neurobiological mechanism that causes exploration and exploitation, and they provide new insights into the choice features used by this mechanism to direct decision-making.

Behavioral assessment of emotion discrimination, emotion regulation, and cognitive control in childhood, adolescence, and adulthood.

Emotion discrimination, emotion regulation, and cognitive control are three related, yet separable processes that emerge over the course of development. The current study tested 100 children, adolescents, and adults on an Emotional Go/Nogo task, illustrating the ability of this paradigm to identify the unique developmental patterns for each of these three processes in the context of both positive (happy) and negative emotions (fear, sad, and anger), across three different age groups. Consistent with previous literature, our findings show that emotion discrimination and regulatory abilities (both cognitive control and emotion regulation) improve steadily for each age group, with each age group showing unique patterns of performance. The findings suggest that emotion regulation is constructed from basic cognition control and emotion discrimination skills. The patterns of behavior from the Emotional Go/Nogo task provide normative benchmark data across a wide range of emotions that can be used for future behavioral and neuroimaging studies that examine the developmental construction of emotion regulatory processes.

Focusing attention on the health aspects of foods changes value signals in vmPFC and improves dietary choice.

Attention is thought to play a key role in the computation of stimulus values at the time of choice, which suggests that attention manipulations could be used to improve decision-making in domains where self-control lapses are pervasive. We used an fMRI food choice task with non-dieting human subjects to investigate whether exogenous cues that direct attention to the healthiness of foods could improve dietary choices. Behaviorally, we found that subjects made healthier choices in the presence of health cues. In parallel, stimulus value signals in ventromedial prefrontal cortex were more responsive to the healthiness of foods in the presence of health cues, and this effect was modulated by activity in regions of dorsolateral prefrontal cortex. These findings suggest that the neural mechanisms used in successful self-control can be activated by exogenous attention cues, and provide insights into the processes through which behavioral therapies and public policies could facilitate self-control.