What Is Targeted When We Train Working Memory? Evidence From a Meta-Analysis of the Neural Correlates of Working Memory Training Using Activation Likelihood Estimation

Impact of combined art-based intervention on functional connectivity of multiple brain networks in older adults along the cognitive continuum: result from a parallel randomised controlled trial

BACKGROUND

Combined art-based interventions (CAIs) are considered effective treatment options for older adults along the cognitive continuum; however, the neural mechanisms underlying associated changes in neurocognitive performance remain unclear. Thus, we aimed to investigate the impact of a CAI programme in older adults along the cognitive continuum and to understand its mechanism.

METHODS

This parallel-arm randomised controlled trial was conducted between April 2021 and January 2023. Participants were randomised in a 1:1 ratio to either intervention group (IG) or waitlist control group (WG). The IG underwent a 16-week CAI programme. Neuropsychological assessments and magnetic resonance imaging were conducted before and after the intervention.

RESULTS

After the intervention, the IG showed greater improvement in general cognitive function, language, and memory than the WG. Significant differences were observed in the functional connectivity (FC) values in the temporal and cerebellar anterior lobes, fusiform, inferior occipital, and lingual gyri, and perirhinal and visual cortices between the groups. Further analyses showed that FC values were reduced in these regions in the IG. In addition, changes in FC values were positively correlated with those in neuropsychological test scores in the IG.

CONCLUSIONS

Our study suggests that the CAI programme can effectively improve general cognitive function, language, and memory in older adults along the cognitive continuum. These improvements may be changed due to decreases in FC in key brain regions, deepening the understanding of the neurocentral mechanisms that act as a tool for improving cognitive function.

TRIAL REGISTRATION

This trial was registered at ChiCTR.org. Identifier: ChiCTR2100044959, 03/04/2021.

Neural correlates of working memory training: An fMRI meta-analysis

Working memory (WM) can be improved by cognitive training. Numerous studies examined neural mechanisms underlying WM training, although with differing conclusions. Therefore, we conducted a meta-analysis to examine the neural substrates underlying WM training in healthy adults. Findings from global analyses showed substantial neural changes in the frontoparietal and subcortical regions. Results from training dosage analyses of WM training showed that shorter WM training could produce neural changes in the frontoparietal regions, whereas longer WM training could produce changes in the subcortical regions (striatum, anterior cingulate cortex, and insula). WM training-induced neural changes were also moderated by the type of training task, with updating tasks inducing neural changes in more regions than maintenance tasks. Overall, these results indicate that the neural changes associated with WM training occur in the frontoparietal network and dopamine-related brain areas, extending previous meta-analyses on WM training and advancing our understanding of the neural underpinnings of WM training effects.

Temporal and spatial variability of dynamic microstate brain network in disorders of consciousness

BACKGROUND

Accurately diagnosing patients with the vegetative state (VS) and the minimally conscious state (MCS) reached a misdiagnosis of approximately 40%.

METHODS

A method combined microstate and dynamic functional connectivity (dFC) to study the spatiotemporal variability of the brain in disorders of consciousness (DOC) patients was proposed. Resting-state EEG data were obtained from 16 patients with MCS and 16 patients with VS. Mutual information (MI) was used to assess the EEG connectivity in each microstate. MI-based features with statistical differences were selected as the total feature subset (TFS), then the TFS was utilized to feature selection and fed into the classifier, obtaining the optimal feature subsets (OFS) in each microstate. Subsequently, an OFS-based MI functional connectivity network (MIFCN) was constructed in the cortex.

RESULTS

The group-average MI connectivity matrix focused on all channels revealed that all five microstates exhibited stronger information interaction in the MCS when comparing with the VS. While OFS-based MIFCN, which only focused on a few channels, revealed greater MI flow in VS patients than in MCS patients under microstates A, B, C, and E, except for microstate D. Additionally, the average classification accuracy of OFS in the five microstates was 96.2%.

CONCLUSION

Constructing features based on microstates to distinguish between two categories of DOC patients had effectiveness.

Effortful and effortless training of executive functions improve brain multiple demand system activities differently: an activation likelihood estimation meta-analysis of functional neuroimaging studies

Both effortful and effortless training have been shown to be effective in enhancing individuals' executive functions. Effortful training improves domain-specific EFs, while effortless training improves domain-general EFs. Furthermore, effortful training has significantly higher training effects on EFs than effortless training. The neural mechanism underlying these different effects remained unclear. The present study conducted meta-analysis on neuroimaging studies to explore the changes of brain activations induced by effortful and effortless training. The results showed that effortful training induced greater activation in superior frontal gyrus, while effortless training induced greater activation in middle frontal gyrus, precuneus and cuneus. The brain regions of MD system enhanced by effortful training were more associated with core cognitive functions underlying EFs, while those enhanced by effortless training were more correlated with language functions. In addition, the significant clusters induced by effortful training had more overlaps with the MD system than effortless training. These results provided us with possibility to discuss the different behavioral results brought by effortful and effortless training.

The effect of oral medications on fMRI brain activation: A randomized, double blind, controlled pilot trial of older women with overactive bladder

INTRODUCTION AND AIM

Observational studies have associated oral anticholinergic medications for overactive bladder (OAB) with cognitive impairment. This is the first pilot trial to compare the effects of two classes of OAB medications on brain activity in women. We evaluated the effect of anticholinergic versus non-anticholinergic (Non-Ach) interventions on regional brain activation during a cognitive task.

METHODS

Twelve cognitively normal women seeking OAB therapy were recruited to a randomized, double-blind, parallel, controlled pilot trial. Whole-brain regional activity at baseline and 29 ± 1 days postintervention was assessed with functional magnetic resonance imaging during a working memory task. Average activation strength by region was compared after anticholinergic, beta-3 agonist, or placebo. Two-way ANOVA compared effects of group and time on average activation strength in anticholinergic versus Non-Ach (beta-3 agonists or placebo) groups.

RESULTS

The mean (SD) age and body mass index of 12 women were 61 (7) years and 36 (7) kg/m². Baseline depression and learning scores differed in the anticholinergic group (n = 3) versus the Non-Ach group (n = 9). Right mamillary body activation postintervention was higher after Non-Ach exposure (F 4.9, p < 0.04). In the full sample of participants at follow-up, there was less activation of the right middle frontal gyrus (p = 0.02), superior frontal gyrus (p < 0.01), and supramarginal (p < 0.01) gyrus.

CONCLUSION

Activation strength in brain regions underlying working memory was lower over time, and recognition scores improved. A powered trial is needed to adequately evaluate for differential effects of OAB oral medications on regional brain activation.