NeuroImage最新文献

Introduction: The study of sex/gender (S/G) differences in neuroscience, particularly in emotional processing, has been hindered by methodological inconsistencies, often producing biased conclusions that overgeneralize brain differences between males and females. Moreover, many studies fail to consider how other sociodemographic factors interact with S/G to influence the brain. This study aims to address these gaps by investigating whether potential S/G effects in brain activation during emotion-evoking functional magnetic resonance imaging (fMRI) tasks are influenced by those factors.

Methods: This meta-analysis followed Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines and was registered on PROSPERO. We searched for peer-reviewed studies on S/G differences in whole-brain activations during fMRI emotion-evoking tasks. Data analysis was conducted using Seed-based d Mapping with Permutation of Subject Images (SDM-PSI). Subgroup analyses were performed based on the type of tasks and on race, and meta-regressions assessed the impact of age, education, and hormonal contraceptive use on the main effects.

Results: 63 studies were included for the meta-analysis, comprising a total of 5,436 individuals from the general population (2,635 females). The main meta-analysis showed no significant S/G activation differences at the whole-brain level. Subgroup analyses, however, revealed significant S/G differences depending on the type of task and the race subgroup, while meta-regression analyses showed significant associations between S/G effects and education and hormonal contraceptive use, with notable shifts in activation patterns across these variables.

Discussion: Our findings highlight the need for more complex, intersectional models that consider the dynamic interplay of biological, psychological, and social factors in shaping S/G differences in brain function and mental health.

Interpersonal coordination requires balancing individual control with interaction-derived synergy, yet it remains unclear when neural coupling contributes beyond behavior. Using an fNIRS hyperscanning paradigm, we examined dyadic rhythmic coordination and jointly modeled behavioral stability, dispositional structure, and interbrain synchrony within a hierarchical neurobehavioral framework. Across models, mean individual stability was negatively associated with dyadic performance, whereas interaction-derived behavioral synergy was the most robust positive predictor. Incorporating dispositional structure showed that larger within-dyad differences in figure-embedding performance impaired coordination, whereas higher dyad-level self-esteem facilitated coordination. The neural coupling index (NCI) showed no reliable main effect after accounting for behavioral and trait factors, but moderation analyses indicated a conditional contribution: interbrain synchrony compensated when behavioral synergy was low, with diminishing benefit as synergy increased. Together, these findings support a hierarchical neurobehavioral architecture in which behavioral synergy provides the primary foundation of coordination, dispositional structure shapes the conditions for synergy, and interbrain synchrony contributes in a context-dependent manner.

Compatible deployment of AI-aided methods for PET quantification is an important prerequisite to maximizing their benefits. We focus on partial volume correction (PVC), which can substantially improve the precision of radiotracer uptake quantification in brain PET for intricate and atrophic regions. Conventional post-reconstruction PVC requires anatomical MR images that are often unavailable or of inadequate quality. We address this limitation by systematically evaluating two AI-aided strategies: (1) indirect PVC, which uses synthesized MR images for anatomical guidance, and (2) direct PVC, which predicts corrected PET images without anatomical processing. Multiple AI architectures were assessed under both strategies, using paired ¹⁸F-FDG PET + CT + MR datasets from multiple scanner sites. Indirect PVC consistently outperformed direct approaches across all tested architectures with the Denoising Diffusion Probabilistic Model yielding the best overall performance while preserving compatibility with standard PET processing pipelines. Both AI-aided approaches increased the utility of standalone ¹⁸F-FDG PET in clinical and research applications without requiring anatomical MR images. Indirect PVC showed advantages in transparency and performance for quantification in smaller anatomical regions, whereas direct PVC may be more suitable for rapid assessment in larger brain regions.

Objective: To extend dynamic tractography-based spike source localization to stereoelectroencephalography (SEEG) and to test whether estimated spike sources (ESSs) and their resection relate to postoperative seizure outcomes across diverse epileptogenic regions and etiologies.

Methods: We studied 24 patients with drug-resistant focal epilepsy who underwent SEEG followed by focal resection or disconnection. For each patient, 100 interictal spikes were analyzed using Morlet wavelet time-frequency transformation (20-70 Hz). Electrode contacts showing significant broadband amplitude augmentation within 50 ms were defined as spike propagation sites. Diffusion MRI tractography generated streamlines from these sites according to observed propagation latencies. ESSs for each spike were defined as the centers of gravity of streamline endpoints. We defined the ESS resection ratio as the proportion of ESSs included within the resected or disconnected area on postoperative MRI and tested whether it was correlated with seizure outcome (ILAE class) and resection volume. Dynamic tractography visualized spike propagation from ESSs to propagation sites through white-matter pathways.

Results: The median (IQR) ESS resection ratio was 75.0% (37.9-85.9). In unilateral cases (n = 18), a higher ESS resection ratio correlated with better outcomes (ρ = -0.51, p = 0.033), irrespective of resection volume. Dynamic tractography successfully visualized physiologically plausible spike propagation. Across 164 tracts, the median (IQR) propagation velocity was 0.99 mm/ms (0.49-1.46).

Conclusions: SEEG dynamic tractography enables localization of spike sources beyond the limits of electrode sampling and visualization of their propagation along white-matter pathways. The extent of ESS removal predicted favorable outcomes-particularly in unilateral cases-suggesting potential utility as a biomarker of the epileptogenic zone.

Background: Cognitive training is a widely recommended technique for cognitive decline and has been shown to improve cognitive functioning. However, the findings on its effect on objective biomarkers of cognitive impairment are highly ambiguous. This study therefore aims to clarify how cognitive training alters brain structure and physiology.

Methods: A systematic search was conducted in three databases (MEDLINE, Embase, and CENTRAL) for eligible articles in November 2023. The search identified 6.134 articles from which 501 remained after title and abstract selection. Eight articles were identified that assessed the efficacy of cognitive training on objective parameters in non-demented adults. Mean differences (MD) and standardized mean differences (SMD of changes between pre- and post-training data were calculated using random-effects models.

Results: 4767 records remained after the removal of duplicates. The selection process ended with 40 eligible articles for qualitative and 8 for quantitative analysis. We did not identify enough articles for the analysis of PET, functional MRI and fluid-based parameters. No significant differences were found in fractional anisotropy (MD=0.01, 95 % Confidence interval (CI): -0.01; 0.04) or in hippocampal volume (SMD=0.03, 95 % CI: -0.01; 0.06). Heterogeneity was high in all analyses.

Conclusions: Training groups showed no significant morphological or microstructural modifications compared to control conditions. The current results of objective markers are not powerful enough to recommend cognitive training as a preventive method. Future research should focus on proper randomization, elimination of baseline differences and use standardized techniques. The review was pre-registered with PROSPERO (ID: CRD42023485440).