Differences in the expression of cortex-wide neural dynamics are related to behavioral phenotype

Individual Differences in White-Matter Microstructure Reflect Variation in Functional Connectivity during Choice

A wealth of neuroscience evidence demonstrates that diet and nutrition play an important role in structural brain plasticity, promoting the development of gray matter volume and maintenance of white matter integrity across the lifespan. However, the role of nutrition in shaping individual differences in the functional brain connectome remains to be well established. We therefore investigated whether nutrient biomarkers known to have beneficial effects on brain structure (i.e., the omega-3 polyunsaturated fatty acids; ω-3 PUFAs), explain individual differences in functional brain connectivity within healthy older adults (N = 96). Our findings demonstrate that ω-3 PUFAs are associated with individual differences in functional connectivity within regions that support executive function (prefrontal cortex), memory (hippocampus), and emotion (amygdala), and provide key evidence that the influence of these regions on global network connectivity reliably predict general, fluid, and crystallized intelligence. The observed findings not only elucidate the role of ω-3 PUFAs in functional brain plasticity and intelligence, but also motivate future studies to examine their impact on psychological health, aging, and disease.

<bold>Objective</bold> To observe the differences in brain network activation and functional connectivity of patients with post-stroke cognitive impairment (PSCI) of different severity using functional near-infrared spectroscopy (fNIRS). <bold>Methods</bold> A total of 40 stroke patients in the outpatient and inpatient Rehabilitation Department in the Pudong District of Huashan Hospital, Fudan University from April to November 2020 were recruited and divided into normal group (<italic>n</italic>=14), mild to moderate group (<italic>n</italic>=11) and severe group (<italic>n</italic>=15) according to the mini-mental state examination (MMSE) score. Fugl-Meyer assessment scale (FMA) and functional comprehensive assessment (FCA) were used to evaluate the motor function of upper and lower limbs; 64-channel fNIRS functional imaging device was used to collect the resting-state brain network data of patients. The whole brain functional connectivity was analyzed based on oxyhemoglobin (HbO₂) and deoxyhemoglobin (HbR). Differences in functional connectivity strengths between homologous and heterologous brain networks in dorsal attention network (DAN), sensorimotor network (SEN), ventral attention network (VAN), frontoparietal network (FPN), default mode network (DMN) and visual network (VIS) regions were analyzed. <bold>Results</bold> (1) Motor function: there was no significant difference in FMA and FCA scores in three groups (<italic>P</italic>&gt;0.05). (2) Whole brain functional connectivity and strength of homologous brain network functional connectivity: there was no significant difference in whole brain functional connectivity based on HbO₂ and HbR in three groups (<italic>P</italic>&gt;0.05). Compared with the normal group, there were significant differences in the strength of functional connectivity of the in the SEN and FPN regions of the HbO₂-based homologous brain network in the severe group (<italic>P</italic>&lt;0.05), but there were no significant differences in the regions of interest of the HbR-based homologous brain network in the three groups (<italic>P</italic>&gt;0.05). (3) Functional connectivity strength of heterologous brain networks: compared with the normal group, the functional connectivity of SEN-VAN, SEN-DMN, SEN-FPN, VAN-FPN and DMN-FPN in the severe group decreased significantly, and the differences were statistically significant (<italic>P</italic>&lt;0.05). Compared with the mild to moderate group, the functional connectivity of SEN-DAN and SEN-FPN in the severe group decreased significantly, and the differences were statistically significant (<italic>P</italic>&lt;0.05). There was no significant difference of strength of functional connectivity based on HbR in the three groups (<italic>P</italic>&gt;0.05). (4) Correlation analysis between SEN-FPN heterologous functional connectivity and MMSE, FCA scores: MMSE score (<italic>r</italic>=0.32, <italic>P</italic>&lt;0.05) and FCA score (<italic>r</italic>=0.38, <italic>P</italic>&lt;0.05) were positively correlated with SEN-FPN functional connectivity. <bold>Conclusion</bold> The SEN-FPN functional connectivity may play an important role in the cognitive function of stroke patients. Altered functional connectivity patterns of SEN-FPN may be closely related to the occurrence and progression of PSCI, and changes in functional connectivity strength of SEN-FPN may be a potential imaging indicator of PSCI.

Functional connectomics is a popular approach to investigate the neural underpinnings of developmental disorders of which attention deficit hyperactivity disorder (ADHD) is one of the most prevalent. Nonetheless, neuronal mechanisms driving the aberrant functional connectivity resulting in ADHD symptoms remain largely unclear. Whereas resting state activity reflecting intrinsic tonic background activity is only vaguely connected to behavioral effects, naturalistic neuroscience has provided means to measure phasic brain dynamics associated with overt manifestation of the symptoms. Here we collected functional magnetic resonance imaging (fMRI) data in three experimental conditions, an active virtual reality (VR) task where the participants execute goal-directed behaviors, a passive naturalistic Video Viewing task, and a standard Resting State condition. Thirty-nine children with ADHD and thirty-seven typically developing (TD) children participated in this preregistered study. Functional connectivity was examined with network-based statistics (NBS) and graph theoretical metrics. During the naturalistic VR task, the ADHD group showed weaker task performance and stronger functional connectivity than the TD group. Group differences in functional connectivity were observed in widespread brain networks: particularly subcortical areas showed hyperconnectivity in ADHD. More restricted group differences in functional connectivity were observed during the Video Viewing, and there were no group differences in functional connectivity in the Resting State condition. These observations were consistent across NBS and graph theoretical analyses, although NBS revealed more pronounced group differences. Furthermore, during the VR task and Video Viewing, functional connectivity in TD controls was associated with task performance during the measurement, while Resting State activity in TD controls was correlated with ADHD symptoms rated over six months. We conclude that overt expression of the symptoms is correlated with aberrant brain connectivity in ADHD. Furthermore, naturalistic paradigms where clinical markers can be coupled with simultaneously occurring brain activity may further increase the interpretability of psychiatric neuroimaging findings.

Alzheimer's disease (AD) is a neurodegenerative disease characterized by cognitive decline. Sex differences in the progression of AD exist, but the neural mechanisms are not well understood. The purpose of the current study was to explore sex differences in brain functional connectivity (FC) at different stages of AD and their predictive ability on Montreal Cognitive Assessment (MoCA) scores using connectome-based predictive modeling (CPM). Resting-state functional magnetic resonance imaging was collected from 81 AD patients (44 females), 78 amnestic mild cognitive impairment patients (44 females), and 92 healthy controls (50 females). The FC analysis was conducted and the interaction effect between sex and group was investigated using two-factor variance analysis. The CPM was used to predict MoCA scores. There were sex-by-group interaction effects on FC between the left dorsolateral superior frontal gyrus and left middle temporal gyrus, left precuneus and right calcarine fissure surrounding cortex, left precuneus and left middle occipital gyrus, left middle temporal gyrus and left precentral gyrus, and between the left middle temporal gyrus and right cuneus. In the CPM, the positive network predictive model significantly predicted MoCA scores in both males and females. There were significant sex-by-group interaction effects on FC between the left precuneus and left middle occipital gyrus, and between the left middle temporal gyrus and right cuneus could predict MoCA scores in female patients. Our results suggest that there are sex differences in FC at different stages of AD. The sex-specific FC can further predict MoCA scores at individual level.

Differences in corticocerebral structure and function between males and females and their effects on behavior and the prevalence of various neuropsychiatric disorders have been considered as a fundamental topic in various fields of neuroscience. Recent studies on working memory (WM) reported the impact of sex on brain connectivity patterns, which reflect the important role of functional connectivity in the sex topic. Working memory, one of the most important cognitive tasks performed by regions of the PFC, can provide evidence regarding the presence of a difference between males and females. The present study aimed to assess sex differences in brain functional connectivity during working memory-related tasks by using functional near-infrared spectroscopy (fNIRS). In this regard, nine males and nine females completed a dual n-back working memory task with two target inputs of color and location stimuli in three difficulty levels (n = 0, 1, 2). Functional connectivity matrices were extracted for each subject for each memory load level. Females made less errors than males while spending more time performing the task for all workload levels except in 0-back related to the color stimulus, where the reaction time of females was shorter than males. The results of functional connectivity reveal the inverse behavior of two hemispheres at different memory workload levels between males and females. In the left hemisphere, males exhibited stronger connectivity compared to the females, while stronger connectivity was observed in the females' right hemisphere. Furthermore, an inverse trend was detected in the channel pairs with significant connectivity in the right hemisphere of males (falling) and females (rising) by enhancing working memory load level. Considering both behavioral and functional results for two sexes demonstrated a better performance in females due to the more effective use of the brain. The results indicate that sex affects functional connectivity between different areas in both hemispheres of the brain during cognitive tasks of varying difficulty levels although the general impression is that spatial capabilities are considered as a performance of the brain's right hemisphere. These results reinforce the presence of a sex effect in the functional imaging studies of hemodynamic function and emphasize the importance of evaluating brain network connectivity for achieving a better scientific understanding of sex differences.

Considerable advances in the role of oxytocin (OT) effect on behavior and the brain network have been made, but the effect of OT on the association between inter-individual differences in functional connectivity (FC) and behavior is elusive. Here, by using a face-perception task and multiple connectome-based predictive models, we aimed to (1) determine whether OT could enhance the association among behavioral performance, resting-state FC (rsFC), and task-state FC (tsFC) and (2) if so, explore the role of OT in enhancing this triangular association. We found that in the OT group, the prediction performance of using rsFC or tsFC to predict task behavior was higher than that of the PL group. Additionally, the correlation coefficient between rsFC and tsFC was substantially higher in the OT group than in the PL group. The strength of these associations could be partly explained by OT altering the brain's FCs related to social cognition and face perception in both the resting and task states, mainly in brain regions such as the limbic system, prefrontal cortex, temporal poles, and temporoparietal junction. Taken together, these results provide novel evidence and a corresponding mechanism for how neuropeptides cause increased associations among inter-individual differences across different levels (e.g., behavior and large-scale brain networks in both resting and task-state), and may inspire future research on the role of neuropeptides in the cross levels association of both clinical and nonclinical use.

An fMRI study of English and Spanish word reading in bilingual adults

Objective: The objective of this study was to investigate resting-state functional connectivity (FC) differences in insular sub-regions during the interictal phase in patients with migraine without aura (MWoA).Methods: Forty-nine MWoA patients (MWoA group) and 48 healthy individuals (healthy control group) were recruited for this study. All of the subjects underwent neurological examination and magnetic resonance imaging (MRI). The MRI data were processed using Brat 1.0 software to obtain a whole-brain FC diagram and using Rest 1.8 software to obtain the FC z-score of the sub-regions of both insulas (six sub-regions on each side). Therefore, there were a total of 12 regions of interest (ROIs) that were used as seed points for the statistical analysis.Results: There was abnormal FC between the insular sub-regions and multiple brain regions in the MWoA patients compared with the healthy control group, and a clear laterality was also observed. In addition, the FC z-score of certain sub-regions was negatively correlated with the disease duration.Conclusion: Different insular sub-regions are functionally associated with different regions of the brain and therefore have different functions. In MWoA, the FC between the insular sub-regions and other brain regions was mostly reduced, while a small amount was increased; additionally, the FC may be ipsilateral with a right-side advantage. Variations in the FC of insular sub-regions can be observed as an important indicator of MWoA.

The human entorhinal-hippocampal circuitry is characterized by an information-specific functional organization where two routes, that are preferentially connected to the parahippocampal cortex or the perirhinal and retrosplenial cortices, divide the entorhinal cortex as well as hippocampal subiculum and CA1 subregions.

To investigate gender differences in functional connectivity during the unattended processing of facial expressions, we recorded visual mismatch negativity (vMMN) in 34 adults using a deviant-standard reverse oddball paradigm. Using wavelet analysis, we calculated the time-frequency (TF) power at each electrode associated with happy-deviant, sad-deviant, happy-standard and sad-standard conditions. We also calculated the phase lag index (PLI) between electrode pairs and analyzed the dynamic network topologies of the functional connectivity for happy and sad vMMNs in the delta (0.5–4 Hz), theta (4–8 Hz), alpha (8–13 Hz), beta (13–30 Hz) and gamma (30–45 Hz) bands. The results showed that females induced stronger TF power and PLI values than males in only the alpha band over the whole brain regarding the vMMN. Moreover, females had a higher ratio of the number of connections between long-distance electrode pairs than males. While theoretical analysis of dynamic network topologies indicated that high node degree values were found in local brain regions of males and in almost the entire female brain, our findings suggested that female brain activation and connections between brain regions are not only stronger but also more widely distributed during the unattended processing of facial expressions than those in males.

Sex differences in resting state functional connectivity across the first two years of life

COVID-19 has been associated with various neurological complications, including cognitive impairments such as memory deficits, attention difficulties, and executive dysfunction. These symptoms raise concerns about potential long-term effects, particularly in individuals with preexisting neurodegenerative conditions. Emerging evidence suggests that systemic inflammation, blood-brain barrier (BBB) dysfunction, and neuroinflammation may contribute to cognitive decline in COVID-19 patients. However, the impact of COVID-19 on functional brain connectivity, particularly in dementia patients, remains unclear.This study aims to investigate the differences in functional connectivity across different frequency bands (delta, theta, alpha, beta, and gamma) in dementia patients with and without a history of COVID-19 (D-COVID and D-nCOVID) compared to a healthy control (HC) group. The study explores whether COVID-19 accelerates neurodegenerative processes by disrupting functional brain networks. Functional connectivity was assessed using electroencephalography (EEG)-based network analysis in three groups: D-COVID, D-nCOVID, and HC. Connectivity metrics were compared across frequency bands, with a focus on local efficiency (LE) and global network alterations. The Kruskal-Wallis test assessed statistical significance, while the Dunn test was used for post-hoc analysis. Findings indicate a significant reduction in functional connectivity across multiple brain regions in dementia patients, with the D-COVID group exhibiting more pronounced declines. The observed decrease in connectivity suggests that COVID-19 may accelerate neurodegenerative processes. Additionally, the HC group demonstrated stronger connectivity and higher LE metrics, highlighting the widespread impact of dementia on brain networks. These findings support the hypothesis that COVID-19 contributes to cognitive decline by exacerbating neurodegenerative mechanisms. The disruption of functional brain connectivity observed in D-COVID patients aligns with previous studies suggesting that SARS-CoV-2 may indirectly promote neuronal degeneration. Further longitudinal studies are needed to determine the long-term cognitive consequences of COVID-19 and potential therapeutic interventions to mitigate these effects.

Abnormal EEG synchronisation in heavily drinking students

Introduction: Stuttering is defined as speech characterized by verbal dysfluencies, but should not be seen as an isolated speech disorder, but as a generalized sensorimotor timing deficit due to impaired communication between speech related brain areas. Therefore we focused on resting state brain activity and functional connectivity.Method: We included 11 patients with developmental stuttering and 11 age matched controls. To objectify stuttering severity and the impact on quality of life (QoL), we used the Dutch validated Test for Stuttering Severity-Readers (TSS-R) and the Overall Assessment of the Speaker’s Experience of Stuttering (OASES), respectively. Furthermore, we used standardized low resolution brain electromagnetic tomography (sLORETA) analyses to look at resting state activity and functional connectivity differences and their correlations with the TSS-R and OASES.Results: No significant results could be obtained when looking at neural activity, however significant alterations in resting state functional connectivity could be demonstrated between persons who stutter (PWS) and fluently speaking controls, predominantly interhemispheric, i.e., a decreased functional connectivity for high frequency oscillations (beta and gamma) between motor speech areas (BA44 and 45) and the contralateral premotor (BA6) and motor (BA4) areas. Moreover, a positive correlation was found between functional connectivity at low frequency oscillations (theta and alpha) and stuttering severity, while a mixed increased and decreased functional connectivity at low and high frequency oscillations correlated with QoL.Discussion: PWS are characterized by decreased high frequency interhemispheric functional connectivity between motor speech, premotor and motor areas in the resting state, while higher functional connectivity in the low frequency bands indicates more severe speech disturbances, suggesting that increased interhemispheric and right sided functional connectivity is maladaptive.