From learned value to sustained bias: how reward conditioning changes attentional priority.

Introduction: Attentional bias to reward-associated stimuli can occur even when it interferes with goal-driven behavior. One theory posits that dopaminergic signaling in the striatum during reward conditioning leads to changes in visual cortical and parietal representations of the stimulus used, and this, in turn, sustains attentional bias even when reward is discontinued. However, only a few studies have examined neural activity during both rewarded and unrewarded task phases. Methods: In the current study, participants first completed a reward-conditioning phase, during which responses to certain stimuli were associated with monetary reward. These stimuli were then included as non-predictive cues in a spatial cueing task. Participants underwent functional brain imaging during both task phases. Results: The results show that striatal activity during the learning phase predicted increased visual cortical and parietal activity and decreased ventro-medial prefrontal cortex activity in response to conditioned stimuli during the test. Striatal activity was also associated with anterior cingulate cortex activation when the reward-conditioned stimulus directed attention away from the target. Discussion: Our findings suggest that striatal activity during reward conditioning predicts the degree to which reward history biases attention through learning-induced changes in visual and parietal activities.

Neural Correlates of the p Factor in Adolescence: Cognitive Control With and Without Enhanced Positive Affective Demands.

BACKGROUND: Recent research has aimed to characterize processes underlying general liability toward psychopathology, termed the p factor. Given previous research linking the p factor with difficulties in both executive functioning and affective regulation, the present study investigated nonaffective and positive affective inhibition in the context of a sustained attention/inhibition paradigm in adolescents exhibiting mild to severe psychopathology. METHODS: Functional magnetic resonance imaging data were collected during an integrated reward conditioning and go/no-go task in 138 adolescents assigned female at birth. We modeled the p factor using hierarchical confirmatory factor analysis. Positive affective inhibition was measured by examining responses to no-go stimuli with a history of reward conditioning. We examined associations between p factor scores and neural function and behavioral performance. RESULTS: Consistent with nonaffective executive function as a primary risk factor, p factor scores were associated with worse behavioral performance and hypoactivation in the left superior frontal gyrus and middle frontal gyrus during response initiation (go trials). The p factor scores were additionally associated with increased error-related signaling in the temporal cortex during incorrect no-go trials. CONCLUSIONS: During adolescence, a period characterized by heightened risk for emergent psychopathology, we observed unique associations between p factor scores and neural and behavioral indices of response initiation, which relies primarily on sustained attention. These findings suggest that shared variation in mental disorder categories is characterized in part by sustained attention deficits. While we did not find evidence that the p factor was associated with inhibition in this study, this observation is consistent with our hypothesis that the p factor would be related to nonaffective control processes.

History of conditioned reward association disrupts inhibitory control: an examination of neural correlates.

The neural processes that support inhibitory control in the face of stimuli with a history of reward association are not yet well understood. Yet, the ability to flexibly adapt behavior to changing reward-contingency contexts is important for daily functioning and warrants further investigation. This study aimed to characterize neural and behavioral impacts of stimuli with a history of conditioned reward association on motor inhibitory control in healthy young adults by investigating group-level effects as well as individual variation in the ability to inhibit responses to stimuli with a reward history. Participants (N = 41) first completed a reward conditioning phase, during which responses to rewarded stimuli were associated with money and responses to unrewarded stimuli were not. Rewarded and unrewarded stimuli from training were carried forward as No-Go targets in a subsequent go/no-go task to test the effect of reward history on inhibitory control. Participants underwent functional brain imaging during the go/no-go portion of the task. On average, a history of reward conditioning disrupted inhibitory control. Compared to inhibition of responses to stimuli with no reward history, trials that required inhibition of responses to previously rewarded stimuli were associated with greater activity in frontal and striatal regions, including the inferior frontal gyrus, insula, striatum, and thalamus. Activity in the insula and thalamus during false alarms and in the ventromedial prefrontal cortex during correctly withheld trials predicted behavioral performance on the task. Overall, these results suggest that reward history serves to disrupt inhibitory control and provide evidence for diverging roles of the insula and ventromedial prefrontal cortex while inhibiting responses to stimuli with a reward history.

Computer-based inhibitory control training in children with Attention-Deficit/Hyperactivity Disorder (ADHD): Evidence for behavioral and neural impact.

Attention-deficit hyperactivity disorder (ADHD) is the most commonly diagnosed psychological disorder of childhood. Medication and cognitive behavioral therapy are effective treatments for many children; however, adherence to medication and therapy regimens is low. Thus, identifying effective adjunct treatments is imperative. Previous studies exploring computerized training programs as supplementary treatments have targeted working memory or attention. However, many lines of research suggest inhibitory control (IC) plays a central role in ADHD pathophysiology, which makes IC a potential intervention target. In this randomized control trial (NCT03363568), we target IC using a modified stop-signal task (SST) training designed by NeuroScouting, LLC in 40 children with ADHD, aged 8 to 11 years. Children were randomly assigned to adaptive treatment (n = 20) or non-adaptive control (n = 20) with identical stimuli and task goals. Children trained at home for at least 5 days a week (about 15m/day) for 4-weeks. Relative to the control group, the treatment group showed decreased relative theta power in resting EEG and trending improvements in parent ratings of attention (i.e. decreases in inattentive behaviors). Both groups showed improved SST performance. There was not evidence for treatment effects on hyperactivity or teacher ratings of symptoms. Results suggest training IC alone has potential to positively impact symptoms of ADHD and provide evidence for neural underpinnings of this impact (change in theta power; change in N200 latency). This shows promising initial results for the use of computerized training of IC in children with ADHD as a potential adjunct treatment option for children with ADHD.

Reward history impacts attentional orienting and inhibitory control on untrained tasks.

It has been robustly shown that stimuli with reward history receive attentional priority. However, the majority of this research tests reward history effects on attentional bias using similar tasks for both the reward learning phase and the unrewarded testing phase, which limits our understanding of how the effects of reward history generalize beyond the trained tasks and mental sets. Across two new experiments, the current study addresses these issues by first associating reward with a stimulus in a visual search paradigm, and then testing value-driven effects of that stimulus in untrained and unrewarded tasks, including a cueing paradigm, a go/no-go task, and a delay discounting task. Results of Experiment 1 demonstrate that history of reward association in a visual search task generalizes to value-driven attentional bias in a different attention paradigm (i.e., cueing), indicating these effects are indeed attributable to imbued value that can transfer to other tasks beyond that in which the reward was trained. The results of Experiment 2 demonstrate that in addition to eliciting attentional orienting on untrained tasks, reward history can lead to better inhibitory control in the go/no-go task. We find no evidence for reward history effects in the delay discounting task. Together, these experiments demonstrate that when the reward association task is in the attention domain, reward history modulates attentional priority, and this effect generalizes to untrained and unrewarded tasks that utilize both spatial and nonspatial attention.

Exogenous vs. endogenous attention: Shifting the balance of fronto-parietal activity.

Despite behavioral and electrophysiological evidence for dissociations between endogenous (voluntary) and exogenous (reflexive) attention, fMRI results have yet to consistently and clearly differentiate neural activation patterns between these two types of attention. This study specifically aimed to determine whether activity in the dorsal fronto-parietal network differed between endogenous and exogenous conditions. Participants performed a visual discrimination task in endogenous and exogenous attention conditions while undergoing fMRI scanning. Analyses revealed robust and bilateral activation throughout the dorsal fronto-parietal network for each condition, in line with many previous results. In order to investigate possible differences in the balance of neural activity within this network with greater sensitivity, a priori regions of interest (ROIs) were selected for analysis, centered on the frontal eye fields (FEF) and intraparietal sulcus (IPS) regions identified in previous studies. The results revealed a significant interaction between region, condition, and hemisphere. Specifically, in the left hemisphere, frontal areas were more active than parietal areas, but only during endogenous attention. Activity in the right hemisphere, in contrast, remained relatively consistent for these regions across conditions. Analysis of this activity over time indicates that this left-hemispheric regional imbalance is present within the FEF early, at 3-6.5 s post-stimulus presentation, whereas a regional imbalance in the exogenous condition is not evident until 6.5-8 s post-stimulus presentation. Overall, our results provide new evidence that although the dorsal fronto-parietal network is indeed associated with both types of attentional orienting, regions of the network are differentially engaged over time and across hemispheres depending on the type of attention.