The fact that a single bout of acute physical exercise has a positive impact on cognition is well-established in the literature, but the neural correlates that underlie these cognitive improvements are not well understood. Here, the use of neuroimaging techniques, such as functional magnetic resonance imaging (fMRI), offers great potential, which is just starting to be recognized. This review aims at providing an overview of those studies that used fMRI to investigate the effects of acute physical exercises on cerebral hemodynamics and cognition. To this end, a systematic literature survey was conducted by two independent reviewers across five electronic databases. The search returned 668 studies, of which 14 studies met the inclusion criteria and were analyzed in this systematic review. Although the findings of the reviewed studies suggest that acute physical exercise (e.g., cycling) leads to profound changes in functional brain activation, the small number of available studies and the great variability in the study protocols limits the conclusions that can be drawn with certainty. In order to overcome these limitations, new, more well-designed trials are needed that (i) use a more rigorous study design, (ii) apply more sophisticated filter methods in fMRI data analysis, (iii) describe the applied processing steps of fMRI data analysis in more detail, and (iv) provide a more precise exercise prescription.

Age-related deterioration in postural control is an important factor decreasing quality of life. Functional neuroimaging studies have shown that the activation of the prefrontal cortex (PFC) during balancing is typically higher in older (OA) compared to younger adults (YA), probably reflecting a mechanism contributing to worsened balance control with aging. Here, we hypothesized that balance training (BAL) shifts PFC activation towards a more efficient pattern, enabling improved balance performance. To test this hypothesis, we conducted a randomized controlled trial with healthy older (65-80 y) and young adults (18-35 y) of both sexes (n = 63) comparing the effects of a 6-month BAL intervention (1 h of BAL twice weekly) against age-matched, non-BAL controls (CON). In both age groups, we found that BAL led to a significant reduction in sway in trained and untrained balance tasks compared to CON, which could still be observed 6 months after the end of training (multivariate p's < .003). In OA, we found a larger reduction in PFC activation assessed with functional near-infrared spectroscopy in BAL compared to CON after training (multivariate p < .02), and a similar yet not significant trend was observed in YA (p < .06). Importantly, in OA, both cross-sectional correlations and longitudinal correlated changes showed that reduced PFC activation was associated with better balance performance. Our results support the idea that BAL may reduce dysfunctional PFC activation in OA, resulting in activation patterns more similar to those of YA, with positive effects on postural control and possibly fall risk.

Multiparameter mapping (MPM) is a quantitative MRI protocol that is promising for studying microstructural brain changes in vivo with high specificity. Reliability values are an important prior knowledge for efficient study design and facilitating replicable findings in development, aging and neuroplasticity research. To explore longitudinal reliability of MPM we acquired the protocol in 31 healthy young subjects twice over a rescan interval of 4 weeks. We assessed the within-subject coefficient of variation (WCV), the between-subject coefficient of variation (BCV), and the intraclass correlation coefficient (ICC). Using these metrics, we investigated the reliability of (semi-) quantitative magnetization transfer saturation (MT_sat), proton density (PD), transversal relaxation (R2*) and longitudinal relaxation (R1). To increase relevance for explorative studies in development and training-induced plasticity, we assess reliability both on local voxel- as well as ROI-level. Finally, we disentangle contributions and interplay of within- and between-subject variability to ICC and assess the optimal degree of spatial smoothing applied to the data. We reveal evidence that voxelwise ICC reliability of MPMs is moderate to good with median values in cortex (subcortical GM): MT: 0.789 (0.447) PD: 0.553 (0.264) R1: 0.555 (0.369) R2*: 0.624 (0.477). The Gaussian smoothing kernel of 2 to 4 mm FWHM resulted in optimal reproducibility. We discuss these findings in the context of longitudinal intervention studies and the application to research designs in neuroimaging field.

The temporal occlusion paradigm is often used in anticipation and decision-making research in sports. Although it is considered as a valid measurement tool, evidence of its reproducibility is lacking but required for future cross-sectional and repeated-measures designs. Moreover, only a few studies on decision making in real-world environments exist. Here, we aimed at (a) implementing a temporal occlusion test with multi-dimensional motor response characteristics, and (b) assessing intra- and inter-session item reliability. Temporally occluded videos of attack sequences in a team handball scenario were created and combined with the SpeedCourt^® contact plate system. Participants were instructed to perform pre-specified defensive actions in response to the video stimuli presented on a life-size projection screen. The intra- and inter-session (after at least 24 h) reproducibility of subjects’ motor responses were analyzed. Significant Cohen’s (0.44–0.54) and Fleiss’ (0.33–0.51) kappa statistics revealed moderate agreement of motor responses with the majority of attack situations in both intra- and inter-session analyses. Participants made faster choices with more visual information about the opponents’ unfolding action. Our findings indicate reliable decisions in a complex, near-game test environment for team handball players. The test provides a foundation for future temporal occlusion studies, including recommendations for new explanatory approaches in cognition research.

The human brain can show remarkable experience‐induced plasticity under conditions such as aging and pathology. However, the mapping of changes provided by many imaging approaches often lacks specificity with respect to biological tissue properties, which is relevant for treatment optimization and the evaluation of health‐promoting lifestyle factors. Training‐induced structural changes in cortical and subcortical gray matter likely reflect a mixture of various microstructural processes. In order to non‐invasively map these different microstructural contributions, we used quantitative magnetic resonance imaging (qMRI) to measure clinically‐relevant brain tissue property changes (such as iron, myelin, and water) in response to 4 weeks of motor balance training in 26 healthy young adults. Training resulted in a regionally‐specific decrease in myelin‐related magnetization transfer saturation (MT_sat) in the left frontal cortex. We also found performance‐related changes in iron‐sensitive transverse relaxation rate (R2*) in visual cortical (signal increase along with positive performance correlation) and limbic subcortical (signal decrease along with negative performance correlation) brain areas. Our study contributes to a growing body of literature investigating motor training‐induced microstructural brain plasticity. Specifically, we provide new insights into microstructural brain changes using whole‐body motor learning (balance practice) and longitudinal quantitative mapping of brain tissue properties.

Motor learning induces widespread brain changes, yet the microstructural mechanisms underlying human white matter (WM) plasticity remain poorly understood. Animal studies have identified roles for neurites, glia, and myelin, but in vivo human evidence has been limited by measurement specificity. Here, we combine multi-contrast quantitative MRI (qMRI), tractometry, and a novel multivariate analysis framework to investigate the microstructural basis of WM plasticity during motor skill learning. In a longitudinal within-subject study, 24 healthy adults completed 4 weeks of balance training following a baseline control period without training. We mapped changes across tractography-defined WM pathways using complementary qMRI markers related to tissue density, myelin, neurite architecture, and iron. Multivariate analysis revealed biologically plausible, behaviorally relevant plasticity in distributed pathways—including the cortico-ponto-cerebello-thalamo-cortical loop, anterior thalamic radiation, and corticospinal tracts—with important contributions from myelin-related metrics. Notably, we observed changes consistent with training-related modulation of the aggregate g -ratio in humans. These spatially distributed effects converged into a single latent dimension predicting neocortical plasticity, suggesting a coordinated, cross-tissue mechanism of brain adaptation. This biologically interpretable framework offers a powerful new approach for investigating WM microstructure in the contexts of plasticity, development, aging, disease, and rehabilitation.