Brain and Cognition最新文献

Older adults with and without Parkinson’s disease show impaired retention after training of motor or cognitive skills. This systematic review with meta-analysis aims to investigate whether adding transcranial direct current stimulation (tDCS) to motor or cognitive training versus placebo boosts motor sequence and working memory training. The effects of interest were estimated between three time points, i.e. pre-training, post-training and follow-up. This review was conducted according to the PRISMA guidelines (PROSPERO: CRD42022348885). Electronic databases were searched from conception to March 2023. Following initial screening, 24 studies were eligible for inclusion in the qualitative synthesis and 20 could be included in the meta-analysis, of which 5 studies concerned motor sequence learning (total n = 186) and 15 working memory training (total n = 650). Results were pooled using an inverse variance random effects meta-analysis. The findings showed no statistically significant additional effects of tDCS over placebo on motor sequence learning outcomes. However, there was a strong trend showing that tDCS boosted working memory training, although methodological limitations and some heterogeneity were also apparent. In conclusion, the present findings do not support wide implementation of tDCS as an add-on to motor sequence training at the moment, but the promising results on cognitive training warrant further investigations.

Time pressure affects multiple cognitive processes but how it affects attention capture remains unclear. Two experiments were carried out in the present study to assess whether time pressure prevents attention from capturing by salient distractors and explore the underlying neural mechanisms using functional near-infrared spectroscopy. The results of behavioral tests showed that the singleton effect decreased (Experiment 2) or even disappeared (Experiment 1) when the subject was under time pressure. Neuroimaging data showed that under time pressure, a salient distractor elicited greater activation in the left middle frontal gyrus/inferior frontal gyrus and bilateral superior parietal lobule, brain areas that are thought to be involved in cognitive inhibition and control of spatial attentional shifts. These findings suggest that the reduction or disappearance of the singleton effect under time pressure results from enhanced inhibition of and/or accelerated disengagement from salient distractors.

Improving postural control in older adults is necessary for reducing fall risk, and prefrontal cortex activation may also play a role. We sought to examine the impact of exercise interventions on postural control and prefrontal cortex activation during standing balance tasks. We hypothesized that balance would improve and prefrontal control would be reduced. We assessed a subset of participants enrolled in a randomized trial of two exercise interventions. Both groups completed strength and endurance training and the experimental treatment arm included training on timing and coordination of stepping. Postural control and prefrontal cortex activation were measured during dual-task standing balance tasks before and after the intervention. Eighteen participants in the standard strengthening and mobility training arm and 16 in the timing and coordination training arm were included. We examined pre- to post-intervention changes within each study arm, and compared them between interventions. Results did not show any pre- to post-intervention changes on standing postural control nor prefrontal cortex activation in either arm. In addition, there were no differences between the two intervention arms in either balance or prefrontal activation. While exercise interventions can improve mobility, we do not demonstrate evidence of improved standing balance or prefrontal control in standing.

Inhibition of return (IOR) has proved to be weakened by audiovisual integration because of the increased perceptual salience of targets. Although other audiovisual interactions, such as crossmodal correspondence, have also been shown to facilitate attentional processes, to the best of our knowledge, no study has investigated the interaction between crossmodal correspondence and IOR. The present study employed Posner’s spatial cueing paradigm and manipulated the cue validity, crossmodal correspondence congruency and time interval of auditory and visual stimuli (AV interval) to explore the effect of crossmodal correspondence on the IOR effect. The behavioral results showed a reduced IOR effect under the correspondence congruency condition in contrast to the correspondence incongruency condition at the AV interval of 200 ms, whereas at an AV interval of 80 ms, the decreased IOR effect under crossmodal correspondence congruency was eliminated. The electrophysiological results showed a reduced amplitude difference in P2 between valid and invalid cue conditions when the crossmodal correspondence effect decreased the IOR effect. The present study provided the first evidence of the weakened effect of the crossmodal correspondence effect on the IOR effect, which could be eliminated by audiovisual integration.

Altruism is defined as the performance of “costly acts that confer economic benefits on other individuals”, which is one of the major puzzles in the behavioural sciences today. Altruistic behaviour not only facilitates interpersonal adaptation and harmony but also enhances social welfare and social responsibility. The right temporo-parietal junction (rTPJ) has been proposed as playing a key role in guiding human altruistic behaviour, but its precise functional contribution to altruistic behaviour in situations of advantageous and disadvantageous inequity remains unclear. The purpose of this study was to modulate the activation of the rTPJ through transcranial direct current stimulation (tDCS) in order to clarify the causal role of the rTPJ in altruistic behaviour in situations of advantageous and disadvantageous inequity. A total of 106 participants were randomly assigned to one of three stimulation conditions: anodal tDCS stimulation on the rTPJ; sham tDCS stimulation on the rTPJ and anodal tDCS stimulation on the primary visual cortex (VC)as the control group, and. After 20 min of stimulation, participants undertook a modified dictator game that measured altruistic behaviour. Mixed-effect logistic regressions were applied to statistical analyses in this study. The results indicated that anodal tDCS over the rTPJ increased participants’ altruistic tendency by increasing their tendency to choose altruistic options in trials with higher cost, as well as their tendency to behave altruistically in situations of advantageous but not disadvantageous inequity. These results suggested that increased neural activity of the rTPJ leads to different impacts on altruism in these two different inequity situations.

Masked word repetition increases “old” responses on an episodic recognition test (Jacoby & Whitehouse, 1989). This effect is commonly attributed to perceptual fluency; that is, unconscious perception of the prime speeds reading of the target and this fluency leads to elevated familiarity. Two experiments directly tested the claim that perceptual fluency is responsible for word priming effects. Experiment 1 held prime-target meaning constant and altered the physical characteristics of match primes (e.g., “RIGHT” primes “RIGHT”) by including both lowercase (e.g, “right”) and mixed case primes (e.g., “rIgHt”). If word priming effects are due to perceptual fluency, then lowering the perceptual overlap between the prime and target should decrease or eliminate word priming effects. Instead, all three conditions showed robust priming effects in the behavioral and ERP (i.e., N400) measures. Experiment 2 equated the prime-target perceptual features and lowered the conceptual overlap by using orthographically similar nonwords as primes (e.g., “JIGHT” primes “RIGHT”). Removing prime-target conceptual overlap eliminated behavioral evidence of priming and N400 ERP differences correlated with priming. The evidence suggests that word priming effects on episodic recognition memory are more likely a product of conceptual fluency than perceptual fluency.

Higher executive control capacity allows people to appropriately evaluate risk and avoid both excessive risk aversion and excessive risk-taking. The neural mechanisms underlying this relationship between executive function and risk taking are still unknown. We used voxel-based morphometry (VBM) analysis combined with resting-state functional connectivity (rs-FC) to evaluate how one component of executive function, model-based learning, relates to risk taking. We measured individuals’ use of the model-based learning system with the two-step task, and risk taking with the Balloon Analogue Risk Task. Behavioral results indicated that risk taking was positively correlated with the model-based weighting parameter ω. The VBM results showed a positive association between model-based learning and gray matter volume in the right cerebellum (RCere) and left inferior parietal lobule (LIPL). Functional connectivity results suggested that the coupling between RCere and the left caudate (LCAU) was correlated with both model-based learning and risk taking. Mediation analysis indicated that RCere-LCAU functional connectivity completely mediated the effect of model-based learning on risk taking. These results indicate that learners who favor model-based strategies also engage in more appropriate risky behaviors through interactions between reward-based learning, error-based learning and executive control subserved by a caudate, cerebellar and parietal network.

Speakers of Mandarin Chinese are thought to conceptualise time along the vertical axis—as evidence for metaphor embodiment—but the extant behavioural evidence remains unclear. Here, we used electrophysiology to test space–time conceptual relationships implicitly in native speakers of Chinese. We employed a modified arrow flanker task, in which the central arrow in a set of three was replaced by a spatial word (e.g., 上–‘up’), a spatiotemporal metaphor (e. g., 上个月–‘last month’, literally ‘up month’) or a non-spatial temporal expression (e.g., 去年 –‘last year’, literally ‘gone year’). N400 modulations of event-related brain potentials served to measure the level of perceived congruency between semantic word content and arrow direction. Critically, we tested whether N400 modulations expected for spatial words and spatial temporal metaphors would generalise to non-spatial temporal expressions. In addition to the predicted N400 effects, we found a congruency effect of a similar magnitude for non-spatial temporal metaphors. On the basis of direct brain measurements indexing semantic processing, and in the absence of contrastive behavioural patterns, we demonstrate that native speakers of Chinese conceptualise time along the vertical axis, and thus have embodied spatiotemporal metaphors.