Brain Imaging and Behavior最新文献

Magnetic resonance imaging (MRI) is frequently used to monitor disease progression in multiple sclerosis (MS). This study aims to systematically evaluate the correlation between MRI measures and histopathological changes, including demyelination, axonal loss, and gliosis, in the central nervous system of MS patients. We systematically reviewed post-mortem histological studies evaluating myelin density, axonal loss, and gliosis using quantitative imaging in MS. Relevant studies were identified through searches in PubMed, EMBASE, and Web of Science. A total of 38 studies involving 1782 regions of interest from 229 subjects were included. Pooled random-effects models were used to calculate the correlation between demyelination, axonal loss, gliosis, and various MRI parameters, including magnetization transfer ratio (MTR), T1 and T2 relaxation times, myelin water fraction (MWF), proton density (PD), and diffusivities. Pair-wise analyses compared results between lesioned and non-lesioned tissues. Our results demonstrated moderate to strong correlations between MRI parameters and myelin density in MS, with correlation coefficients: T1 (0.72), T2 (0.72), MTR (-0.73), FA (-0.73), RD (0.70), MD (0.70), MWF (-0.82), and PD (0.73). Interestingly, stronger correlations were found in lesioned tissues compared to non-lesioned tissues (P < 0.001). Moderate correlations were found between MRI parameters and axonal loss and gliosis. Our study reveals significant correlations between MRI techniques and histological assessments of myelin, axonal damage, and gliosis in MS. MRI metrics exhibited a more robust association with demyelination in lesioned areas than in non-lesioned brain tissue, highlighting the pronounced degree of myelin degradation in MS lesions. Further investigation is warranted to corroborate these results and refine MRI-based monitoring of MS pathology.

Tryptophan has been shown to improve cognitive functions, but whether these benefits emanate from changes in hippocampal structure or other mechanisms like enhanced serotonin pathways remains unclear. This study aimed to examine the relationship between tryptophan levels and hippocampal volumes in individuals with mild cognitive impairment (MCI) and to determine if changes in hippocampal volume correlate with cognitive function. A total of 499 individuals with MCI were recruited based on ADNI's clinical criteria. Cognitive function was assessed using the ADAS-Cog scale, and hippocampal volumes were measured through MRI using semi-automated Medtronic Surgical Navigation Technologies (SNT). Tryptophan levels in plasma were analyzed using a nuclear magnetic resonance (NMR)-based assay. This study used two models: One unadjusted and another adjusted for covariates such as age, gender, handedness, and ApoE ɛ3 and ɛ4. In both models, higher tryptophan levels were significantly associated with increased bilateral hippocampal volumes, with a stronger effect in the left hippocampus. Furthermore, larger hippocampal volumes were linked to improved cognitive performance. Mediation analysis showed that hippocampal volumes mediated the relationship between plasma tryptophan levels and cognitive function. These findings suggested that elevated plasma tryptophan levels support cognitive health by maintaining hippocampal structural integrity, underscoring its potential role in preserving cognitive function in individuals with MCI.

To characterize local functional connectivity (FC) differences in children with autism spectrum disorder (ASD) compared to typically developed (TD) children, and to analyze the correlation between local FC and the atypical behavior in autistic children. Thirty children with ASD and 25 TD children were recruited. Participants underwent rs-fMRI scans, and regional homogeneity (ReHo) of specific brain regions was measured. Performance was assessed using the Autism Behavior Checklist (ABC) and the Gesell Development Diagnosis Scale (GDDS). Children with ASD demonstrated reduced ReHo in the right occipital lobe lingual, left postcentral, and left precuneus compared with TD children. Within the ASD group, the ABC total score was negatively related to ReHo values in both the left postcentral and left precuneus. The ReHo value in the left postcentral was negatively correlated with ABC scores related to sensory and body/object use, while the ReHo value in the left precuneus was negatively correlated with scores related to social skills and self-help. The mean Developmental Quotient (DQ) of GDDS was positively correlated with the ReHo value in the right occipital lobe lingual. Besides, the ReHo value in this region was positively correlated with the DQ of adaptive behavior. The ReHo value in the left postcentral was positively correlated with the DQ of fine motor skills (p < 0.05 for all). Children with ASD exhibit reduced local FC in specific brain regions, which are associated with specific performances in autism. These findings may provide a novel insight into the pathophysiological mechanisms of ASD.

Children diagnosed with attention-deficit/hyperactivity disorder (ADHD) often display reduced cortical volume and thickness, as well as changes in cortical folding. However, the impact of ADHD on cortical morphology in young adults remains elusive. This study aimed to characterize cortical thickness, gyrification, and sulcal depth profiles in adults aged 18-26 years old with ADHD. In this cross-sectional study, we employed multiparameter analyses between two groups: an ADHD group of individuals diagnosed with and medicated daily for ADHD (n = 30) and a non-ADHD group with age- and sex-matched individuals free from lifetime ADHD diagnosis (n = 30). The ADHD group exhibited significant cortical thinning in fronto-parieto-temporal regions, including the left superior parietal lobule, bilateral inferior temporal gyrus, and right lateral orbitofrontal gyrus, relative to the non-ADHD group. Greater gyrification and deeper sulcal depth were evident in various fronto-occipital-temporal regions in the ADHD group, although two regions (right postcentral and inferior temporal gyri) displayed shallower sulcal depth compared to the non-ADHD group. These data suggest that ADHD-related disparities persist into young adulthood, with alterations in brain morphology potentially serving as biomarkers for ADHD diagnosis in young adults.

Resting-state functional connectivity has become a valuable tool in studying post-stroke aphasia (PSA). However, the specific distribution of increased functional connectivity areas (IFCAs) in PSA patients after speech-language therapy (SLT) remains unclear, particularly compared with the intrinsic brain network (IBN) observed in healthy controls. This study aimed to explore the effects of SLT and spontaneous recovery on functional connectivity changes in the brain. We recruited twenty healthy controls and twelve PSA patients, each of whom underwent one month of SLT. The Chinese version of the Western Aphasia Battery (WAB) was administered to assess language function recovery. The Dice coefficients were calculated between each patient's lesion and the reference lesion, which showed moderate to high intensity. The results revealed a close association between the spatial distribution of IFCAs and improvements in specific language functions. Our findings indicate that the distribution pattern of IFCAs may serve as a significant marker of recovery in PSA patients.

Here, we explore the relationship between transcranial direct current stimulation (tDCS) and brain-behavior interactions. We propose that tDCS perturbation allows for the investigation of relationships between brain volume and behavior. We focused on the hippocampus (HPC) and cerebellum (CB) regions that are implicated in our understanding of memory and motor skill acquisition. Seventy-four young adults (mean age: 22 ± 0.42 years, mean education: 14.7 ± 0.25 years) were randomly assigned to receive either anodal, cathodal, or sham stimulation. Following stimulation, participants completed computerized tasks assessing working memory and sequence learning in a magnetic resonance imaging (MRI) environment. We investigated the statistical interaction between CB and HPC volumes. Our findings showed that individuals with larger cerebellar volumes had shorter reaction times (RT) on a high-load working memory task in the sham stimulation group. In contrast, the anodal stimulation group exhibited faster RTs during the low-load working memory condition. These RT differences were associated with the cortical volumetric interaction between CB-HPC. Literature suggests that anodal stimulation down-regulates the CB and here, those with larger volumes perform more quickly, suggesting the potential need for additional cognitive resources to compensate for cerebellar downregulation or perturbation. This new insight suggests that tDCS can aid in revealing structure-function relationships, due to greater performance variability, especially in young adults. It may also reveal new targets of interest in the study of aging or in diseases where there is also greater behavioral variability.

Physical exercise is a promising intervention to improve brain white matter integrity. In the PAM study, exercise intervention effects on white matter integrity were investigated in breast cancer patients. Chemotherapy-treated breast cancer patients with cognitive problems were randomized 2-4 years post-diagnosis to an exercise (n = 91) or control group (n = 90). The 6-month exercise intervention consisted of four hours/week of aerobic and resistance training. White matter integrity was measured at baseline and 6-month follow-up with fractional anisotropy (FA) and mean diffusivity (MD), which were derived from magnetic resonance diffusion tensor imaging (DTI). Both DTI metrics were analyzed whole brain and voxel-wise with a modified tract based spatial statistics (TBSS) procedure. Other measurements included cognition and physical fitness. Exercise effects were analyzed with multiple regression analyses. An explorative analysis was conducted in highly fatigued patients. DTI scans were available for 69 patients of the intervention (age = 52.3 ± 8.9yrs.) and 72 patients of the control group (age = 53.2 ± 8.6yrs.). Whole brain and voxel-wise analyses revealed no significant intervention effects on FA and MD. In highly fatigued patients (exercise: n = 32; control: n = 24), significant clusters of decreased FA post-intervention were observed in the left inferior and superior longitudinal fasciculus. Mean FA in these clusters was not predictive of cognition. A 6-month exercise intervention did not affect white matter integrity in chemotherapy-treated breast cancer patients. However, in highly fatigued breast cancer patients a significant FA decrease was observed post-intervention. The direction of these results is unexpected, and more research is needed to further understand these results.

Childhood obstructive sleep apnea syndrome (OSAS) disrupts normal ventilation and sleep structure and affects cognitive functions. However, the neurophysiological mechanisms underlying cognitive impairment are unclear. This study investigates the topological connectivity of white matter networks in children with moderate to severe OSAS and explores the underlying mechanisms of cognitive impairment. We collected clinical data of patients with moderate to severe OSAS (n = 43) and non-OSAS (n = 30). Intelligence testing was conducted using the China Wechsler Intelligence Scale for Children-Fourth Edition (C-WISC IV), including Processing speed, Working memory, Verbal comprehension, Perceptual reasoning, and Full-scale intelligence quotient (FSIQ). DTI data were collected using 3.0T MRI scanner (Ingenia, Philips, Netherlands). White matter network topology connections were analyzed using FSL and DSI Studio and inter group differences were statistically assessed. The difference of clinical and intelligence test was calculated by two sample t-test. Pearson correlation analysis was employed to examine the correlation between the abnormal white matter network metrics and cognitive function in OSAS patients. Clustering coefficient (Cp) and global efficiency (Eg), nodal degree (Dc), and nodal efficiency (Ne) were lower in the OSAS group (p < 0.05). Correlations between white matter network metrics and cognitive function: The Cp and Eg were positively correlated with Perceptual reasoning, and the shortest path length (Lp) was negatively correlated with Perceptual reasoning. The results indicate that there was impairment of cognitive function and abnormality of topological structural connectivity in white matter networks for children with OSAS. The Cp, Eg, and Lp correlate with Perceptual reasoning, indicating that abnormal topological structural connectivity of the white matter network might be neurofunctional basis for impaired perceptual reasoning.

This study aims to determine if the six different types of communication (Directive, Imaginative, Reflective, Persuasive, Harmonizing, Promoting), as presented in the Process Communication Model, correlate with a respective neural pathway. Participants were 30 medical students with no past medical history. They underwent functional magnetic resonance imaging (fMRI) while watching videos typical of each communication type. By comparing each of the six experimental conditions with all the other ones, common activations were detected in the core memory network. Assertive communication styles (Directive, Imaginative) generated activations in conflict detection and resolution related areas, with a predominance in the frontal lobe. Emotive communication (Harmonizing, Promoting) highlighted activations associated with the interpretation of social and emotional cues, with a temporo-occipital predominance. There were no significant activations for the Reflective and Persuasive channel, the two channels that were most coherent with the subjects' base patterns and communication. This study indicated that out of the six communication types that were analyzed, four have a specific and congruous underlying cerebral process. This shows that neural response patterns vary across different communication styles, reflecting differences in cognitive and emotional processing.

Concussion is a common injury in sports that causes neurological damage, leading to memory loss and difficulty concentrating. Insufficient recovery time may result in significant long-term harm to individuals. Several neuroimaging techniques have been used to understand the pathophysiological changes following concussion, and how long individuals need to recover before returning to play. Despite the progress in neuroimaging concussion research, few studies have considered whether females sustain different effects on the brain and how recovery from concussion might differ from males. Thus, we conducted a systematic review of the existing literature to highlight sex differences in concussion with neuroimaging techniques. By searching four different databases, studies were selected if they used a neuroimaging technique to examine sex differences following concussion in athletes over the age of 18. After screening 2295 studies from an initial search, 15 were found to match the selection criteria. Nine papers established some difference between males and females, however many of these studies were not designed to specifically examine sex differences, and hence conclusions in this regard are somewhat limited. A further common limitation among these papers was a lack of whole brain scans, instead relying on regions of interest analyses, which reduces the ability to compare studies effectively. The current systematic review has highlighted the need for future studies to specifically consider whether, and how sex influences the impact and trajectory of brain recovery from concussion. This can then help to inform suitable amendments to current concussion return-to-play protocols for male and female athletes.