Feedback associated with expectation for larger-reward improves visuospatial working memory performances in children with ADHD

Evidence for the Beneficial Effect of Reward on Working Memory: A Meta-Analytic Study

Rewards act as external motivators and can improve performance in various cognitive tasks. However, previous research demonstrated mixed findings regarding the effect of reward on working memory (WM) performance, and the question of whether reward enhances WM performance is arguable. It remains unclear how the effect of reward on WM can be influenced by various factors, such as types of reward and experimental paradigms. In this meta-analytic study, we systematically investigated the effect of reward on WM by analyzing data from 51 eligible studies involving a total of 1767 participants. Our results showed that reward robustly enhanced WM performance, with non-monetary rewards inducing more benefits than monetary rewards. This may be because, while both types of reward could induce extrinsic motivation, non-monetary rewards enhanced intrinsic motivation while monetary rewards reduced it. Notably, all three reward methods-reward binding, reward expectation, and subliminal reward-effectively improved WM performance, with the reward binding paradigm exhibiting the greatest effects. This finding suggests that the reward effect can be attributed to both increasing the total amount of WM resources and improving the flexibility of resource reallocation. Moreover, the type of WM, the experimental paradigms, and the outcome measures are three moderators that should be jointly considered when assessing the reward effects on WM. Overall, this meta-analytic study provides solid evidence that reward improves WM performance and reveals possible mechanisms underlying these improvements.

Dissociable effects of positive feedback on the capture and inhibition of impulsive behavior in adolescents with ADHD versus typically developing adolescents

The present study investigated how enhancing motivation by delivering positive feedback (a smiley) after a successful trial could affect interference control in adolescents with Attention Deficit Hyperactivity Disorder (ADHD) and in their typically developing (TD) peers. By using a Simon task within the theoretical framework of the "activation-suppression" model, we were able to separately investigate the expression and the inhibition of impulsive motor behavior. The experiment included 19 adolescents with ADHD and 20 TD adolescents in order to explore whether data found in adolescents with ADHD were similar to those found in TD adolescents. Participants performed the Simon task in two conditions: a condition with feedback delivered after each successful trial and a condition with no feedback. The main findings were that increasing motivation by delivering positive feedback increased impulsive response in both groups of adolescents. It also improved the efficiency of impulsive motor action inhibition in adolescents with ADHD but deteriorated it in TD adolescents. We suggest that 1/increased motivation could lead adolescents to favor fast responses even if incorrect, and 2/the differential effect of feedback on the selective suppression of impulsive motor action in both groups could be due to different baseline DA levels.

Semantic and syntactic specialization during auditory sentence processing in 7-8-year-old children

Previous studies indicate that adults show specialized syntactic and semantic processes in both the temporal and frontal lobes during language comprehension. Neuro-cognitive models of language development argue that this specialization appears earlier in the temporal than the frontal lobe. However, there is little evidence supporting this proposed progression. Our recently published study (Wang, Rice, & Booth, 2020), using multivoxel pattern analyses, detected that children as young as 5 to 6 years old exhibit specialization and integration in the temporal lobe, but not the frontal lobe. In the current study, we used the same approach to examine semantic and syntactic specialization in children ages 7 to 8 years old. We found support for semantic specialization in the left middle temporal gyrus (MTG) for correct sentences and in the triangular part of the left inferior frontal gyrus (IFG) for incorrect sentences. We also found that the left superior temporal gyrus (STG) played an integration role and was sensitive to both semantic and syntactic processing during both correct and incorrect sentence processing. However, there was no support for syntactic specialization in 7- to 8-year-old children. As compared to our previous study on 5- to 6-year-old children, which only showed semantic specialization in the temporal lobe, the current study suggests a developmental progression to semantic specialization in the frontal lobe. This project represents an important step forward in testing neuro-cognitive models of language processing in children.

Reward Expectation Differentially Modulates Global and Local Spatial Working Memory Accuracy

Although it has been suggested that reward expectation affects the performance of spatial working memory tasks, controversial results have been found in previous experiments. Hence, it is still unclear to what extent reward expectation has an effect on working memory. To clarify this question, a memory-guided saccade task was applied, in which participants were instructed to retain and reconstruct a temporospatial sequence of four locations by moving their eyes in each trial. The global- and local-level spatial working memory accuracies were calculated to determine the reward effect on the global and local level of processing in spatial working memory tasks. Although high reward expectation enhanced the encoding of spatial information, the percentage of trials in which the cued location was correctly fixated decreased with increment of reward expectation. The reconstruction of the global temporospatial sequence was enhanced by reward expectation, whereas the local reconstruction performance was not affected by reward. Furthermore, the improvements in local representations of uncued locations and local sequences were at the cost of the representation of cued locations. The results suggest that the reward effect on spatial working memory is modulated by the level of processing, which supports the flexible resource theory during maintenance.

ADHD and the Choice of Small Immediate Over Larger Delayed Rewards: A Comparative Meta-Analysis of Performance on Simple Choice-Delay and Temporal Discounting Paradigms

Objective: Impulsive choices can lead to suboptimal decision making, a tendency which is especially marked in individuals with ADHD. We compared two different paradigms assessing impulsive choice: the simple choice paradigm (SCP) and the temporal discounting paradigm (TDP). Method: Random effects meta-analyses on 37 group comparisons (22 SCP; 15 TDP) consisting of 3.763 participants (53% ADHD). Results: Small-to-medium effect sizes emerged for both paradigms, confirming that participants with ADHD choose small immediate over large delayed rewards more frequently than controls. Moderation analyses show that offering real rewards in the SCP almost doubled the odds ratio for participants with ADHD. Conclusion: We suggest that a stronger than normal aversion toward delay interacts with a demotivating effect of hypothetical rewards, both factors promoting impulsive choice in participants with ADHD. Furthermore, we suggest the SCP as the paradigm of choice due to its larger ecological validity, contextual sensitivity, and reliability.

A neuroimaging dataset on working memory and reward processing in children with and without ADHD

This article describes the public neuroimaging dataset entitled “Working Memory and Reward in Children with and without Attention Deficit Hyperactivity Disorder (ADHD)” available on OpenNeuro.org. This dataset uses functional magnetic resonance imaging (fMRI) while participants complete 8 n-back tasks designed to explore working memory, monetary reward, and feedback processing in typically developing children and children diagnosed with ADHD. In addition, this dataset includes longitudinal scores from a battery of standardized measures of cognitive ability, ADHD symptoms, and reading skill. Neuroimaging and standardized testing data were collected from 79 children, aged 8.6–12.0, of which 35 had a formal diagnosis of ADHD at session T1. 48 children returned two years later to complete standardized testing at session T2. Although some work has been published on the spatial working memory task, future research could investigate the verbal working memory and longitudinal data which are unexplored. In addition, this dataset is accompanied by an adult dataset, including 24 participants completing the same tasks entitled, “Working Memory and Reward in Adults” and available on OpenNeuro.org.

Cognitive rehabilitation in children with attention deficit- hyperactivity disorder: Transferability to untrained cognitive domains and behavior

Transferability of cognitive rehabilitation is a crucial point for efficacy. The purpose of the present study is to determine the transfer effect of cognitive rehabilitation to the untrained cognitive domains and behavior in children with attention deficit- hyperactivity disorder (ADHD). Thirty children with ADHD randomly allocated into two intervention and control groups. The intervention group received cognitive rehabilitation in 12-15 sessions. Analyses indicated that the experimental group shows an improvement in the trained domain. The result found a lack of near transfer to selective attention and inhibitory control with a successful far transfer effect to the risky decision making and delay discounting. Furthermore, the transfer occurred to behavioral symptoms of the intervention group. Attention and working memory training decrease delay discounting and delay discounting. The near transfer is not a prerequisite of far transfer. Cognitive rehabilitation can transfer horizontally to other cognitive domains at the same level and vertically to behaviors in a top-down manner.

Acoustic closed-loop stimulation during sleep improves consolidation of reward-related memory information in healthy children but not in children with attention-deficit hyperactivity disorder

Study Objectives

Slow oscillations (SO) during slow-wave sleep foster the consolidation of declarative memory. Children with attention-deficit hyperactivity disorder (ADHD) display deficits in the sleep-associated consolidation of declarative memory, possibly due to an altered function of SO. The present study aimed at enhancing SO activity using closed-looped acoustic stimulation during slow-wave sleep in children with ADHD.

Methods

A total of 29 male children (14 with ADHD; aged 8–12 years) participated in a double-blind, placebo-controlled study trial. Children spent two experimental nights in a sleep lab, one stimulation night and one sham night. A declarative learning task (word-pair learning) with a reward condition was used as a primary outcome. Secondary outcome variables were a procedural memory (serial reaction time) and working memory (WM; n-back) task. Encoding of declarative and procedural memory took place in the evening before sleep. After sleep, the retrieval took place followed by the n-back task.

Results

The stimulation successfully induced SO activity during sleep in children with and without ADHD. After stimulation, only healthy children performed better on high-rewarded memory items (primary outcome). In contrast, there were indications that only children with ADHD benefitted from the stimulation with respect to procedural as well as WM performance (secondary outcome).

Conclusions

We were able to show that the acoustic closed-loop stimulation can be applied to enhance SO activity in children with and without ADHD. Our data indicate that SO activity during sleep interacts with subsequent memory performance (primary outcome: rewarded declarative memory; secondary outcome: procedural and WM) in children with and without ADHD.

Visual Category Learning Results in Rapid Changes in Brain Activation Reflecting Sensitivity to the Category Relation between Perceived Objects and to Decision Correctness

Little is known about the time scales in which sensitivity to novel category identity may become evident in visual and executive cortices in visual category learning (VCL) tasks and the nature of such changes in brain activation. We used fMRI to investigate the processing of category information and trial-by-trial feedback information. In each VCL task, stimuli differed in three feature dimensions. In each trial, either two same-category stimuli or two different-categories stimuli were presented. The participant had to learn which feature dimension was relevant for categorization based on the feedback that followed each categorization decision. We contrasted between same-category stimuli trials and different-category trials and between correct and incorrect categorization decision trials. In each trial, brain activation in the visual stimuli processing phase was modeled separately from activation during the later feedback processing phase. We found activation in the lateral occipital complex, indicating sensitivity to the category relation between stimuli, to be evident in VCL within only few learning trials. Specifically, greater lateral occipital complex activation was evident when same-category stimuli were presented than when different-category stimuli were presented. In the feedback processing phase, greater activation in both executive and visual cortices was evident primarily after “misdetections” of same-category stimuli. Implications regarding the contribution of different learning trials to VCL, and the respective role of key brain regions, at the onset of VCL, are discussed.

Functional neuroimaging of visuospatial working memory tasks enables accurate detection of attention deficit and hyperactivity disorder

Finding neurobiological markers for neurodevelopmental disorders, such as attention deficit and hyperactivity disorder (ADHD), is a major objective of clinicians and neuroscientists. We examined if functional Magnetic Resonance Imaging (fMRI) data from a few distinct visuospatial working memory (VSWM) tasks enables accurately detecting cases with ADHD. We tested 20 boys with ADHD combined type and 20 typically developed (TD) boys in four VSWM tasks that differed in feedback availability (feedback, no-feedback) and reward size (large, small). We used a multimodal analysis based on brain activity in 16 regions of interest, significantly activated or deactivated in the four VSWM tasks (based on the entire participants' sample). Dimensionality of the data was reduced into 10 principal components that were used as the input variables to a logistic regression classifier. fMRI data from the four VSWM tasks enabled a classification accuracy of 92.5%, with high predicted ADHD probability values for most clinical cases, and low predicted ADHD probabilities for most TDs. This accuracy level was higher than those achieved by using the fMRI data of any single task, or the respective behavioral data. This indicates that task-based fMRI data acquired while participants perform a few distinct VSWM tasks enables improved detection of clinical cases.