Brain Topography最新文献

Inhibitory control is crucial for humans to select useful information from the complex environment. The bilateral DLPFC, which is implicated in inhibitory control, was activated under psychological stress. The present study investigated the influence of acute psychological stress on inhibitory control process using the color-word Stroop task. The stress was induced by the Trier Social Stress Task (TSST). After TSST (stress group) or placebo TSST (control group), the male participants performed a color-word Stroop task, and their brain activity was measured using functional near-infrared spectroscopy (fNIRS). The results showed that elevated subjective stress, heart rate, and salivary cortisol were found in the stress than control groups, indicating that the stress had been induced successfully. Reduced RT Stroop effect (RT_incongruent - RT_congruent) was found for the stress group compared to the control group. The fNIRS results revealed greater activation in bilateral dorsolateral prefrontal cortex (DLPFC) in the stress than control groups. In addition, the activation in left DLPFC was increased for the stress than control groups in incongruent trials, but not in the congruent trials, resulting in a larger magnitude of the activation Stroop effect (activation_incongruent - activation_congruent) in the stress group. These results demonstrate that acute psychological stress may potentially improve inhibitory control in healthy men.

Accumulating evidence has revealed deviations in neural network connectivity among individuals with suicidal ideation (SI). We sought to explore the neural network dynamics of suicide attempt (SA) survivors. We recruited 31 SA survivors, 33 individuals with SI, and 33 normal people controls (NP). To investigate brain network dynamics, we collected 64-channel resting-state EEG recordings and conducted microstate analysis on all participants. Compared to the NP group, both SA survivors and SI group displayed greater coverage and occurrence of microstates A and B. Notably, relative to the SI group, a marked elevation in the occurrence of microstates D and E and a significant increased coverage of microstate E, were observed in the SA group. The SA group exhibited significantly shorter durations of microstates C, D, and E, along with reduced occurrence and coverage of microstate C, compared to the SI group. The SA group exhibited significantly greater transition probabilities from microstate E to any other microstate compared to the SI group. Furthermore, higher suicide risk scores significantly correlated increased occurrence of microstate D, occurrence of microstate E, and coverage of microstate E. A key limitation is the cross-sectional design, which restricts the capacity to establish whether microstate dynamics can serve as predictors of future suicidal behavior. The present results imply that the microstate dynamics of SA survivors are distinct from those of individuals with SI. These results indicate that microstate dynamics could potentially act as neurobiomarkers for distinguishing suicidal behavior and SI.

Functional magnetic resonance imaging (fMRI) is a valuable neuroimaging tool for studying brain function and connectivity. However, the blood oxygen level dependent (BOLD) signal used in fMRI is affected by various physiological factors, such as cardiac and respiratory activity, which can influence functional connectivity patterns. As such, physiological noise correction is a crucial preprocessing step in fMRI data analysis. When concurrent physiological recordings are available, researchers often generate nuisance regressors to account for the effect of heart rate and respiratory variations by convolving physiological response functions (PRF) with the corresponding physiological signals. However, it has been suggested that the PRF characteristics may vary across subjects and different regions of the brain, as well as across scans of the same subject. To explore this variability, we examine the performance of several different PRF models, in terms of BOLD variance explained, using resting-state fMRI data from the Human Connectome Project (N = 100). We examined both one-input (heart rate or respiration) and two-input (heart rate and respiration) PRF models and show that allowing PRFs to vary across subjects and brain regions generally improves PRF model performance. For one-input models, the improvement in model performance gained by allowing spatial variability was most prominent for respiration, particularly for a subset of the subjects (about a third) examined. Subject-specific or regional variability in cardiac response only enhanced performance when using two-input models. Overall, our results highlight the importance of considering spatial and subject-specific variability in PRFs when analyzing fMRI data, particularly regarding respiratory-related fluctuations.

Cancer-related fatigue (CRF) significantly diminishes the quality of life of cancer survivors; however, objective diagnostic markers and the underlying neurophysiological mechanisms remain unclear. This study aimed to identify noninvasive EEG-based biomarkers of CRF by examining cortical activity and functional connectivity. We recorded resting-state and task-related [repetitive submaximal elbow flexions (EFs) until self-perceived exhaustion] high-density electroencephalography (EEG) from 10 cancer survivors with CRF and 14 healthy controls (HC). In our analysis, task-induced fatigue was categorized as mild, moderate, and severe, corresponding to the level of fatigue perceived at the beginning, middle, and end of the task period. Our study revealed the following significant findings: (1) Linear mixed-effects modeling of event-related desynchronization (ERD) EEG analysis during the EF task demonstrated significant effects of group and fatigue levels in the alpha band (8-12 Hz). (2) EF task-specific functional connectivity was estimated using the debiased weighted phase-lag index (dwPLI), which demonstrated reduced inter-regional connectivity in the M1 and prefrontal regions in the CRF group compared with the HC group. (3) The dwPLI analysis identified significantly reduced alpha-band connectivity strength in the CRF group, particularly between the right supramarginal gyrus and other brain regions during mild fatigue. (4) Additionally, resting-state EEG exhibited globally elevated delta-band (1-4 Hz) activity in CRF survivors than HC, potentially reflecting chronic fatigue. These observations emphasize the clinical relevance of resting-state EEG, motor activity-related ERD and functional brain connectivity as potential CRF biomarkers. Future research should validate these findings in larger cohorts and provide insights into more objective CRF diagnosis and the development of personalized interventions for alleviating CRF.

To advance the application of functional near-infrared spectroscopy (fNIRS) in brain-computer interface (BCI) technology, we investigated cortical activation patterns associated with auditory selective attention. Using a dichotic listening paradigm, participants were presented with simultaneous music and reading sounds to the left or right ear. During fNIRS recordings, they were instructed to selectively attend to the sound attribute (music vs. reading) or the spatial location (left vs. right ear). Cortical activity differences related to attentional targets were analyzed using a two-way analysis of variance (ANOVA), with sound attribute and spatial information as factors. Our results revealed a significant main effect of the sound attribute factor across multiple measurement channels. Notably, the right parietal region exhibited consistently greater activation when attention was directed toward music compared to reading sounds. Conversely, bilateral dorsolateral prefrontal cortex (DLPFC) channels showed higher activation when participants attended to reading sounds than to music. These findings indicate that cortical activation patterns are modulated by auditory attentional states based on sound attributes. Furthermore, preliminary classification analyses achieved an accuracy of 73.7% in discriminating attentional targets (music vs. reading sounds), demonstrating the feasibility of fNIRS-based BCI applications.

Optically pumped magnetometers (OPMs) represent a significant advancement in magnetoencephalography (MEG), offering high sensitivity without cryogenic cooling and enabling flexible sensor placement. In this pilot study, we evaluated whether a small, zero-contact 16-channel OPM array can capture movement-related beta-band modulation (event-related desynchronization/synchronization; ERD/ERS) in healthy participants and explored feasibility in a single patient with amyotrophic lateral sclerosis (ALS). MEG responses to visually cued active and passive finger movements were recorded in a magnetically shielded room with the OPM array and separately with 306-channel superconducting quantum interference device (SQUID). Time-frequency analyses focused on beta-band activity across baseline, ERD, and ERS periods. In healthy participants, both OPM and SQUID successfully captured movement-related beta oscillations, with no significant differences between active and passive conditions or between measurement systems, based on non-parametric tests. In the ALS patient, movement-related responses were attenuated and more affected by artifacts in the OPM data compared with SQUID, limiting interpretability. Although movement artifacts were noted, the OPM system provided group-level results in healthy controls comparable to SQUID-based MEG, demonstrating its viability and potential for rapid, flexible deployment. These findings indicate that a compact zero-contact OPM array can reliably measure movement-related cortical beta activity and may offer a cost-effective alternative to cryogenic MEG systems. In ALS, however, the present results should be interpreted strictly as a feasibility demonstration, and larger patient cohorts will be required to establish reliability and clinical utility.

Transcranial electrical stimulation (tES) is one of the most widely used non-invasive brain stimulation (NIBS) methods employed to investigate the causal relationship between brain regions and cognitive functions. tES has been utilized in numerous studies to explore the role of brain regions involved in decision-making. The present study aims to review tES studies conducted to examine the causal relationship of neural regions involved in ambiguous and risky decision-making. A systematic review was conducted based on the PRISMA guidelines (PROSPERO record: CRD42024571443). A systematic search was performed in the PubMed database from 1985 to 2024. The search results were screened for eligibility based on inclusion and exclusion criteria. In addition to the qualitative synthesis, a random-effects meta-analysis was performed on eligible studies reporting sufficient statistical detail. This systematic review examined 19 studies involving 837 participants (351 men and 486 women) with an average age of 23.15 years, investigating the role of different brain regions in risky and ambiguous decision-making. Qualitative synthesis showed that the DLPFC has the strongest association with risky decision-making, particularly with significant changes observed after anodal stimulation in the right hemisphere and cathodal stimulation in the left hemisphere. Limited evidence also suggested roles for frontal asymmetry, the right orbitofrontal cortex (rOFC), and the dorsal anterior cingulate cortex (dACC) in risky decision-making. In the domain of ambiguous decision-making, only a few studies demonstrated the effect of anodal stimulation of the right DLPFC (RDLPFC). The only study using transcranial alternating current stimulation (tACS) also showed a connection between the beta frequency band and the DLPFC in risky decision-making. Complementing these results, the quantitative synthesis of 6 studies (14 effect sizes, n = 378) showed no significant overall effect of tES on decision-making, though subgroup analyses revealed polarity- and site-specific patterns, with cathodal stimulation of the dACC showing the most robust effect. The combined qualitative and quantitative evidence supports a causal role of prefrontal and cingulate regions in risky decision-making, with effects shaped by stimulation polarity and cortical target. Given the limited number of studies conducted, future research should focus on ambiguous decision-making. The use of neuroimaging techniques and simulations may enhance the results obtained.

Neurofeedback (NFB) therapy based on spectral neuromarkers of Attention-Deficit/Hyperactivity Disorder (ADHD) has faced challenges regarding its efficacy and replicability. In this study, we investigate whether a microstate-based EEG marker, recently implicated in ADHD, could serve as a novel target for neurofeedback. Emerging research suggests that ADHD patients often exhibit an excess of microstate D, a state characterized by fronto-central cortical activity linked to attentional functions. This study aims to assess whether neurofeedback training can effectively modulate microstate D in adult ADHD patients, along with its short-term neurobehavioral correlates. We employed a within-subject, crossover design with 19 adults with ADHD, who participated in two counterbalanced neurofeedback sessions: one aimed at upregulating microstate D percent time coverage, and the other at downregulating it. While patients were able to volitionally increase microstate D during the upregulation session, no significant change was observed during the downregulation session. Direct comparison between the two sessions revealed that online control of microstate D was specific to the closed-loop feedback, rather than merely task engagement. No short-term effects of the neurofeedback sessions were observed. No moderate nor major adverse effects were reported. Despite lack of statistical power, this study provides controlled indicationfor the specificity and safety of neurofeedback training based on microstate D in adult ADHD patients. Although the short-term design did not yield clinical improvements, the findings demonstrate the feasibility of microstate-based neurofeedback protocols in a clinical population and offer valuable technical and methodological insights for designing futur studies.

The functional brain networks related to procedural learning (PL) have never been explored in children with self-limited focal epilepsies of childhood (SeLFE), despite their role in the development of various sequence-related sensorimotor, language, and cognitive abilities that are impaired in this clinical population. Our study fills this gap by investigating PL and its interaction with the rapid reorganisation of resting-state functional connectivity (rsFC) in SeLFE. A serial reaction time task, preceded and followed by resting-state magnetoencephalography (MEG) recordings, was used to assess PL in 10 children with SeLFE and 28 age-, sex- and IQ-matched typically developing (TD) children. Pre- to post-learning rsFC changes were estimated using band-limited power envelope correlation, after regressing interictal epileptic discharges (IEDs) in SeLFE patients. rsFC maps were compared between groups and correlated with PL and IED frequency. Compared to TD peers, children with SeLFE showed atypical pre- to post-learning rsFC changes within widespread antero-posterior brain networks in theta, alpha and low beta bands, as well as reduced PL performance negatively correlated with sleep IED frequency. This MEG study is the first to demonstrate reduced PL abilities combined with atypical post-learning reorganisation of rsFC in children with SeLFE compared to TD peers. These results suggest that the pathophysiology of SeLFE, including the chronic repetition of IEDs during sleep across development, have a detrimental impact on the acquisition of PL brain-behaviour processes in these patients.

Major depressive disorder (MDD) is marked by cognitive and affective dysfunctions associated with altered prefrontal cortical activity. While high-definition transcranial direct current stimulation (HD-tDCS) shows promise in modulating these deficits, little is known about the differential effects of targeting specific prefrontal subregions. This study investigated whether HD-tDCS over the dorsolateral (DLPFC) or ventrolateral (VLPFC) prefrontal cortex produces distinct behavioural and neurophysiological effects in patients with MDD, focusing on cognitive control, mood, and functional brain connectivity. Twenty-six patients with MDD received ten sessions of HD-tDCS over the left DLPFC, left VLPFC, or sham stimulation. Assessments were performed pre-intervention, post-intervention, and at one-month follow-up. Measures included the Beck Depression Inventory (BDI), World Health Organization Quality of Life - BREF (WHOQOL-BREF), and performance on cognitive tasks. A subset underwent resting-state functional near-infrared spectroscopy (fNIRS) to assess changes in prefrontal connectivity. DLPFC stimulation led to early and sustained improvements in depressive symptoms, executive function (e.g., Trail Making Test, Wisconsin Card Sorting Task), and quality of life domains. VLPFC stimulation produced delayed improvements, particularly in inhibitory control (e.g., Attention Network Test). fNIRS revealed no significant within-group changes in global connectivity, but at follow-up, the DLPFC group showed greater prefrontal connectivity than both VLPFC and sham, suggesting lasting functional reorganization. VLPFC stimulation did not alter global connectivity, possibly reflecting more localized or subcortical effects. HD-tDCS can differentially modulate cognitive and affective processes in MDD. DLPFC stimulation promotes broader, earlier, and more durable effects, while VLPFC stimulation may exert more specific, delayed influences. Functional connectivity measures enhance interpretation of neuromodulatory outcomes in clinical research.