Dorsal Attention Network Research Articles

A parcellation-based connectomic model of hemispatial neglect.

Hemispatial neglect is characterized by a reduced awareness to stimuli on the contralateral side. Current literature suggesting that damage to the right parietal lobe and attention networks may cause hemispatial neglect is conflicting and can be improved by investigating a connectomic model of the "neglect system" and the anatomical specificity of regions involved in it. A meta-analysis of voxel-based morphometry magnetic resonance imaging (MRI) studies of hemispatial neglect was used to identify regions associated with neglect. We applied parcellation schemes to these regions and performed diffusion spectrum imaging (DSI) tractography to determine their connectivity. By overlaying neglect areas and maps of the attention networks, we studied the relationship between them. The meta-analysis generated a list of 13 right hemisphere parcellations. These 13 neglect-related parcellations were predominantly linked by the superior longitudinal fasciculus (SLF) throughout a fronto-parietal-temporal network. We found that the dorsal and ventral attention networks showed partial overlap with the neglect system and included various other higher-order networks. We provide an anatomically specific connectomic model of the neurobehavioral substrates underlying hemispatial neglect. Our model suggests a fronto-parietal-temporal network linked via the SLF supports the functions impaired in neglect and implicates various higher-order networks which are not limited to the attention networks.

Large-scale effective connectivity analysis reveals the existence of two mutual inhibitory systems in patients with major depression

It is posited that cognitive and affective dysfunction in patients with major depression disorder (MDD) may be caused by dysfunctional signal propagation in the brain. By leveraging dynamic causal modeling, we investigated large-scale directed signal propagation (effective connectivity) among distributed large-scale brain networks with 43 MDD patients and 56 healthy controls. The results revealed the existence of two mutual inhibitory systems: the anterior default mode network, auditory network, sensorimotor network, salience network and visual networks formed an “emotional” brain, while the posterior default mode network, central executive networks, cerebellum and dorsal attention network formed a “rational brain”. These two networks exhibited excitatory intra-system connectivity and inhibitory inter-system connectivity. Patients were characterized by potentiated intra-system connections within the “emotional/sensory brain”, as well as over-inhibition of the “rational brain” by the “emotional/sensory brain”. The hierarchical architecture of the large-scale effective connectivity networks was then analyzed using a PageRank algorithm which revealed a shift of the controlling role of the “rational brain” to the “emotional/sensory brain” in the patients. These findings inform basic organization of distributed large-scale brain networks and furnish a better characterization of the neural mechanisms of depression, which may facilitate effective treatment.

Neurophysiological markers in community-dwelling older adults with mild cognitive impairment: an EEG study

BackgroundNeurodegeneration and structural changes in the brain due to amyloid deposition have been observed even in individuals with mild cognitive impairment (MCI). EEG measurement is considered an effective tool because it is noninvasive, has few restrictions on the measurement environment, and is simple and easy to use. In this study, we investigated the neurophysiological characteristics of community-dwelling older adults with MCI using EEG.MethodsDemographic characteristics, cognitive function, physical function, resting-state MRI and electroencephalogram (rs-EEG), event-related potentials (ERPs) during Simon tasks, and task proportion of correct responses and reaction times (RTs) were obtained from 402 healthy controls (HC) and 47 MCI participants. We introduced exact low-resolution brain electromagnetic tomography-independent component analysis (eLORETA-ICA) to assess the rs-EEG network in community-dwelling older adults with MCI.ResultsA lower proportion of correct responses to the Simon task and slower RTs were observed in the MCI group (p < 0.01). Despite no difference in brain volume between the HC and MCI groups, significant decreases in dorsal attention network (DAN) activity (p < 0.05) and N2 amplitude of ERP (p < 0.001) were observed in the MCI group. Moreover, DAN activity demonstrated a correlation with education (Rs = 0.32, p = 0.027), global cognitive function (Rs = 0.32, p = 0.030), and processing speed (Rs = 0.37, p = 0.010) in the MCI group. The discrimination accuracy for MCI with the addition of the eLORETA-ICA network ranged from 0.7817 to 0.7929, and the area under the curve ranged from 0.8492 to 0.8495.ConclusionsThe eLORETA-ICA approach of rs-EEG using noninvasive and relatively inexpensive EEG demonstrates specific changes in elders with MCI. It may provide a simple and valid assessment method with few restrictions on the measurement environment and may be useful for early detection of MCI in community-dwelling older adults.

Brain structural and functional signatures of multi-generational family history of suicidal behaviors in preadolescent children.

Parent-child transmission of suicidal behaviors has been extensively studied, but the investigation of a three-generation family suicide risk paradigm remains limited. In this study, we aimed to explore the behavioral and brain signatures of multi-generational family history of suicidal behaviors (FHoS) in preadolescents, utilizing a longitudinal design and the dataset from Adolescent Brain and Cognitive DevelopmentSM Study (ABCD Study®), which comprised 4 years of data and includes a total of 9,653 preadolescents. Our findings revealed that multi-generational FHoS was significantly associated with an increased risk of problematic behaviors and suicidal behaviors (suicide ideation and suicide attempt) in offspring. Interestingly, the problematic behaviors were further identified as a mediator in the multi-generational transmission of suicidal behaviors. Additionally, we observed alterations in brain structure within superior temporal gyrus (STG), precentral/postcentral cortex, posterior parietal cortex (PPC), cingulate cortex (CC), and planum temporale (PT), as well as disrupted functional connectivity of default mode network (DMN), ventral attention network (VAN), dorsal attention network (DAN), fronto-parietal network (FPN), and cingulo-opercular network (CON) among preadolescents with FHoS. These results provide compelling longitudinal evidence at the population level, highlighting the associations between multi-generational FHoS and maladaptive behavioral and neurodevelopmental outcomes in offspring. These findings underscore the need for early preventive measures aimed at mitigating the familial transmission of suicide risk and reducing the global burden of deaths among children and adolescents.

Resting-state fMRI is associated with trauma experiences, mood and psychosis in Afro-descendants with bipolar disorder and schizophrenia

BackgroundBipolar disorder (BD) and schizophrenia (SCZ) may exhibit functional abnormalities in several brain areas, including the medial temporal and prefrontal cortex and hippocampus; however, a less explored topic is how brain connectivity is linked to premorbid trauma experiences and clinical features in non-Caucasian samples of SCZ and BD. Methods: Sixty-two individuals with SCZ (n = 20), BD (n = 21), and healthy controls (HC, n = 21) from indigenous and African ethnicity were submitted to clinical screening (Di-PAD), traumata experiences (ETISR-SF), cognitive and functional MRI assessment. The item psychosis/hallucinations in SCZ patients showed a negative correlation with the global efficiency (GE) in the right dorsal attention network. The items mania, irritable mood, and racing thoughts in the Di-PAD scale had a significant negative correlation with the GE in the parietal right default mode network. Conclusions: Differences in the activation of specific networks were associated with earlier disease onset, history of physical abuse, and more severe psychotic and mood symptoms in SCZ and BD subjects of indigenous and black ethnicity. Findings provide further evidence on SZ and BD's brain connectivity disturbances, and their clinical significance, in non-Caucasian samples.

Resting state correlates of picture description informativeness in left vs. right hemisphere chronic stroke.

Despite a growing emphasis on discourse processing in clinical neuroscience, relatively little is known about the neurobiology of discourse production impairments. Individuals with a history of left or right hemisphere stroke can exhibit difficulty with communicating meaningful discourse content, which implies both cerebral hemispheres play a role in this skill. However, the extent to which successful production of discourse content relies on network connections within domain-specific vs. domain-general networks in either hemisphere is unknown. In this study, 45 individuals with a history of either left or right hemisphere stroke completed resting state fMRI and the Cookie Theft picture description task. Participants did not differ in the total number of content units or the percentage of interpretative content units they produced. Stroke survivors with left hemisphere damage produced significantly fewer content units per second than individuals with right hemisphere stroke. Intrinsic connectivity of the left language network was significantly weaker in the left compared to the right hemisphere stroke group for specific connections. Greater efficiency of communication of picture scene content was associated with stronger left but weaker right frontotemporal connectivity of the language network in patients with a history of left hemisphere (but not right hemisphere) stroke. No significant relationships were found between picture description measures and connectivity of the dorsal attention, default mode, or salience networks or with connections between language and other network regions. These findings add to prior behavioral studies of picture description skills in stroke survivors and provide insight into the role of the language network vs. other intrinsic networks during discourse production.

Differences in Brain Network Topology Based on Alcohol Use History in Adolescents.

Approximately 6 million youth aged 12 to 20 consume alcohol monthly in the United States. The effect of alcohol consumption in adolescence on behavior and cognition is heavily researched; however, little is known about how alcohol consumption in adolescence may alter brain function, leading to long-term developmental detriments. In order to investigate differences in brain connectivity associated with alcohol use in adolescents, brain networks were constructed using resting-state functional magnetic resonance imaging data collected by the National Consortium on Alcohol and NeuroDevelopment in Adolescence (NCANDA) from 698 youth (12-21 years; 117 hazardous drinkers and 581 no/low drinkers). Analyses assessed differences in brain network topology based on alcohol consumption in eight predefined brain networks, as well as in whole-brain connectivity. Within the central executive network (CEN), basal ganglia network (BGN), and sensorimotor network (SMN), no/low drinkers demonstrated stronger and more frequent connections between highly globally efficient nodes, with fewer and weaker connections between highly clustered nodes. Inverse results were observed within the dorsal attention network (DAN), visual network (VN), and frontotemporal network (FTN), with no/low drinkers demonstrating weaker connections between nodes with high efficiency and increased frequency of clustered nodes compared to hazardous drinkers. Cross-sectional results from this study show clear organizational differences between adolescents with no/low or hazardous alcohol use, suggesting that aberrant connectivity in these brain networks is associated with risky drinking behaviors.

The Pre-Interictal Network State in Idiopathic Generalized Epilepsies.

Generalized spike wave discharges (GSWDs) are the typical electroencephalographic findings of Idiopathic Generalized Epilepsies (IGEs). These discharges are either interictal or ictal and recent evidence suggests differences in their pathogenesis. The aim of this study is to investigate, through functional connectivity analysis, the pre-interictal network state in IGEs, which precedes the formation of the interictal GSWDs. A high-density electroencephalogram (HD-EEG) was recorded in twenty-one patients with IGEs, and cortical connectivity was analyzed based on lagged coherence and individual anatomy. Graph theory analysis was used to estimate network features, assessed using the characteristic path length and clustering coefficient. The functional connectivity analysis identified two distinct networks during the pre-interictal state. These networks exhibited reversed connectivity attributes, reflecting synchronized activity at 3-4 Hz (delta2), and desynchronized activity at 8-10.5 Hz (alpha1). The delta2 network exhibited a statistically significant (p < 0.001) decrease in characteristic path length and an increase in the mean clustering coefficient. In contrast, the alpha1 network showed opposite trends in these features. The nodes influencing this state were primarily localized in the default mode network (DMN), dorsal attention network (DAN), visual network (VIS), and thalami. In conclusion, the coupling of two networks defined the pre-interictal state in IGEs. This state might be considered as a favorable condition for the generation of interictal GSWDs.

The co-activation pattern between the DMN and other brain networks affects the cognition of older adults: evidence from naturalistic stimulation fMRI data.

Brain function changes affect cognitive functions in older adults, yet the relationship between cognition and the dynamic changes of brain networks during naturalistic stimulation is not clear. Here, we recruited the young, middle-aged and older groups from the Cambridge Center for Aging and Neuroscience to investigate the relationship between dynamic metrics of brain networks and cognition using functional magnetic resonance imaging data during movie-watching. We found six reliable co-activation pattern (CAP) states of brain networks grouped into three pairs with opposite activation patterns in three age groups. Compared with young and middle-aged adults, older adults dwelled shorter time in CAP state 4 with deactivated default mode network (DMN) and activated salience, frontoparietal and dorsal-attention networks (DAN), and longer time in state 6 with deactivated DMN and activated DAN and visual network, suggesting altered dynamic interaction between DMN and other brain networks might contribute to cognitive decline in older adults. Meanwhile, older adults showed easier transfer from state 6 to state 3 (activated DMN and deactivated sensorimotor network), suggesting that the fragile antagonism between DMN and other cognitive networks might contribute to cognitive decline in older adults. Our findings provided novel insights into aberrant brain network dynamics associated with cognitive decline.

Interaction between Oligomeric Amyloid‐β and Cardiovascular Risk Factors is Associated with Executive and Dorsal Attention Network Dysfunction in Pre‐dementia

AbstractBackgroundOligomeric amyloid‐β(OAβ) accumulation within brain tissue has been shown to be associated with major AD neuropathological features including tau pathology, synaptic loss, inflammation and oxidative damage; as well as cognitive impairment in dementia cohorts (Celine.E.N et.al.,2018). However, association of OAβ with functional connectivity (FC) and cardiovascular risk factors is not clearly known in the pre‐dementia stage. We aimed to examine association of FC with OAβ and other dementia risk factors in a pre‐dementia cohort to understand the underlying mechanisms related to OAβ.MethodsWe included 98 age and sex matched participants and classified them into OAβ+(28) and OAβ‐(70) subgroups using a OAβ cut‐off ratio of ≥ 0.9 (MDS‐ OAβ Test Kit, PeopleBio Inc, South Korea). Participants completed resting‐state functional MRI, clinical and lifestyle history questionnaires, blood, and neuropsychological assessments for global cognition on Montreal cognitive assessment and Visual Cognitive Assessment at Dementia Research Centre (Singapore). The Cardiovascular Risk Factors, Aging and Dementia (CAIDE) risk score was computed, and independent sample or chi‐squared analysis were performed to evaluate group‐level participant characteristics. Region‐of‐interest based FC analysis for 19 seeds from executive control (ECN), default‐mode, salience and dorsal‐attention networks (DAN) was performed to examine the network‐based FC differences in OAβ+ and OAβ‐ groups in association with CAIDE using ANCOVA model.ResultsMean age of OAβ+ and OAβ‐ were 62.04±8.84, and 62.05±8.07 (Table‐1). No significant FC differences were observed between OAβ+ vs OAβ‐ subjects. There were no significant FC differences related to CAIDE score in OAβ+ and OAβ‐ groups. Nonetheless, the OAβ*CAIDE interaction showed significant FC changes. The OAβ+*CAIDE interaction analyses showed reduced FC within ECN and DAN (Figure‐1a). Whereas OAβ‐*CAIDE interaction showed reduced FC only within ECN (Figure‐1b). Furthermore, OAβ interaction with apolipoprotein‐ε4 (OAβ*APOE4) was found to further influence FC trends in ECN and DAN (Figure‐1c,1d).ConclusionWhile no FC differences were observed between OAβ+ vs OAβ‐ subjects, the interaction between CAIDE and APOE4 moderated FC changes within the ECN and DAN. These observations in a pre‐dementia cohort suggest that the presence of cerebrovascular risk factors may result in differential FC dysfunction in ECN and DAN depending on APOE4 status.

Cerebellum Hyperactivity and its cortical connectivity in Alzheimer’s Disease (AD) utilizing FDG PET and Resting State Functional Magnetic Resonance.

AbstractBackgroundThe role of the cerebellum in Alzheimer’s disease (AD) is not fully understood. There are a few studies that have demonstrated impaired cortical – cerebellar connectivity in AD. Additionally, transgenic mouse studies clearly show amyloid‐β (Aβ) deposition in the cerebellum affecting synaptic transmission and plasticity, sometimes before plaque formation. To characterize metabolic activity in the cerebellum, we analyzed 18F‐fluorodeoxyglucose (FDG) positron emission tomography (PET) and resting‐state functional MRI (rs‐fMRI) data in AD, mild‐cognitive impaired (MCI), and age‐matched cognitively normal (CN) subjects from the Alzheimer’s Disease Neuroimaging Initiative (ADNI). Our focus was on the intrinsic functional connectivity of the cerebellum with three brain networks: the default mode network (DMN), dorsal attention network (DAN), and the primary olfactory cortex (POC) in the medial temporal lobe. We hypothesized that the resting state functional connectivity of cerebellar regions (that showed differential FDG metabolic activity) would exhibit impaired brain‐wide network connectivity.MethodA group of 272 ADNI subjects (CN = 80, MCI = 149, AD = 43) with FDG‐PET scans were analyzed in this study. All 272 subjects did not have consistent rs‐fMRI data therefore, we analyzed 160 subjects (CN = 80, MCI = 84, AD = 29) that had consistent rs‐fMRI data acquisition parameters. The PET preprocessing was performed in SPM12. Partial volume correction was performed using the Van‐Cittert deconvolution technique. The rs‐fMRI data was preprocessed in DPABI; PET and rs‐fMRI data were normalized to the Montreal Neurological Institute template. DMN and DAN masks were downloaded from neurovault.org. The Statistical analyses were performed in DPABI.ResultThe SPM group analysis of PET data identified crus II, right cerebellum 4,5 and vermis lobule 6 as hyperactive (increased glucose metabolism) in AD and MCI compared to CN (Figure 1). Subsequent analyses identified brain regions within the DMN, DAN, and POC that are correlated with hyperactive cerebellar regions. Similarity analyses detected impaired resting state functional connectivity of hyperactive cerebellar regions with the three brain networks (Figure 2).ConclusionThe hyper‐metabolism in the cerebellum may reflect disruption of local and brain‐wide network connectivity due to neurodegeneration. Observed hyper‐metabolism may be related to inhibitory dynamics of the cerebellum — providing a hypothetical mechanism to explain the susceptibility of brain networks in AD.

Relationship between loss of awareness of cognitive decline and tau pathology in the Alzheimer’s disease spectrum: modulatory role of resting‐state functional connectivity

AbstractBackgroundPatients with Alzheimer’s disease (AD) often demonstrate anosognosia, which is reduced awareness of cognitive decline. Anosognosia has been associated with tau accumulation (d'Oleire Uquillas et al., 2020) and impaired resting‐state functional connectivity (FC) in self‐referential networks (Vannini et al., 2017, Valera‐Bermejo et al., 2022). The explicit links between AD pathological deposits and large‐scale functional networks associated with anosognosia have yet to be elucidated. Here, we sought to examine whether FC plays a modulatory role in the effect of tau on awareness in participants across the AD spectrum.MethodWe included 58 participants from two observational cohorts—44 asymptomatic (Clinical Dementia Rating (CDR) global score = 0) and 14 symptomatic (CDR≥0.5) individuals (Table1). Awareness was measured as the participant‐study partner discrepancy on the Cognitive Function Index. Flortaucipir‐PET was used to quantify tau accumulation, and segregation analysis was applied to resting‐state fMRI data to asses within‐network connectivity. For both modalities, the mean value in each of the Yeo 7 networks was used. First, a linear regression model was performed to assess the association between awareness and group (i.e., symptomatic/asymptomatic). Linear regression models were also used to assess the relationship between awareness and tau in the 7 networks, separately. Finally, we examined the effect of the FC×tau interaction on awareness. All models were adjusted for age, sex, and education.ResultHolding age, sex, and education constant, mean awareness was 0.18 lower in symptomatic (vs. asymptomatic) participants (p&lt;0.01). Lower awareness was associated with a higher tau burden in all 7 networks (Table2). Interaction effects between tau and FC were observed. Specifically, reduced awareness was associated with high tau burden when the salience network was less functionally connected (Figure1A; β = ‐0.23, p = 0.02) and when the dorsal attention network was more functionally connected (Figure1B; β = 0.70, p = 0.03). For all other networks, the relationship between awareness and tau was not modified by the FC of the same network (Table2).ConclusionThese findings provide new insights into the neuropathological correlates of anosognosia in AD. It suggests that anosognosia is not only due to local pathology in single brain areas but also to altered connectivity between them, especially within self‐referential networks.

Executive functioning, ADHD symptoms and resting state functional connectivity in children with perinatal stroke

Perinatal stroke describes a group of focal, vascular brain injuries that occur early in development, often resulting in lifelong disability. Two types of perinatal stroke predominate, arterial ischemic stroke (AIS) and periventricular venous infarction (PVI). Though perinatal stroke is typically considered a motor disorder, other comorbidities commonly exist including attention-deficit hyperactivity disorder (ADHD) and deficits in executive function. Rates of ADHD symptoms are higher in children with perinatal stroke and deficits in executive function may also occur but underlying mechanisms are not known. We measured resting state functional connectivity in children with perinatal stroke using previously established dorsal attention, frontoparietal, and default mode network seeds. Associations with parental ratings of executive function and ADHD symptoms were examined. A total of 120 participants aged 6–19 years [AIS N = 31; PVI N = 30; Controls N = 59] were recruited. In comparison to typically developing peers, both the AIS and PVI groups showed lower intra- and inter-hemispheric functional connectivity values in the networks investigated. Group differences in between-network connectivity were also demonstrated, showing weaker anticorrelations between task-positive (frontoparietal and dorsal attention) and task-negative (default mode) networks in stroke groups compared to controls. Both within-network and between-network functional connectivity values were highly associated with parental reports of executive function and ADHD symptoms. These results suggest that differences in functional connectivity exist both within and between networks after perinatal stroke, the degree of which is associated with ADHD symptoms and executive function.

Relationship between default mode network and posterior resting‐state electroencephalographic delta rhythms in cognitively unimpaired seniors and patients with dementia due to Alzheimer’s

AbstractBackgroundAlzheimer’s disease dementia (ADD) is the most common neurodegenerative dementing disorder explaining about 60‐70% of 50 million patients worldwide (www.who.int). Some previous studies in ADD patients showed significant neurodegenerative processes as revealed by reduced gray matter volume in the cerebral cortex, including the default mode network (DMN), dorsal attention (DAN), and sensorimotor (SMN) cortical networks from structural magnetic resonance imaging (sMRI). Other studies in these patients reported the “slowing” of the resting‐state eyes‐closed electroencephalographic (rsEEG) rhythms reflecting vigilance dysfunctions. Here we tested the hypothesis of a significant relationship between these neurodegenerative and neurophysiological readouts, thus suggesting the sensitivity of rsEEG activity to intrinsic AD processes.MethodClinical, sMRI, and rsEEG rhythms in demographic‐ and age‐matched ADD (N = 45) and healthy cognitively unimpaired (Nold, N = 40) persons were available from an international archive (www.pdwaves.eu). Individual alpha frequency peak was used to determine the alpha frequency band on a personal basis. Fixed beta bands were considered. The eLORETA freeware estimated rsEEG sources in posterior (i.e., central, parietal, and occipital) cortical regions of interest. Freeware platforms served to estimate the normalized gray matter volume in the DMN, DAN, and SMN cortical networks from sMRI.ResultThe results (Fig. 1) showed: (1) lower DMN, DAN, and SMN volumes (maximum effects in the DMN), higher posterior rsEEG delta‐theta source activities, and lower rsEEG alpha source activities in the ADD than in the Nold group; (2) substantial inverse correlation between the DMN volume and the posterior rsEEG delta‐theta source activities in the ADD and Nold participants; and (3) a mediating effect of the posterior rsEEG delta‐theta source activities in the correlation between the DMN volume and the global cognitive status across all participants.ConclusionThese results suggest a prominent relationship between DMN atrophy and the posterior rsEEG delta‐theta rhythms across physiological and AD‐related aging. As such, they support the enrichment of the ATN model for an extension to “Physiology” (P) = A‐T‐P‐N, as the physiology of the oscillatory activity within large inter‐connected neuronal populations due to disruptive effects of AD‐related neuropathology can be additionally informative.

EEG responses and mental health restoration according to VR soundscape experience

This study investigates the neural correlates of restorative responses to urban and natural soundscapes, utilizing Heart Rate Variability (HRV) and Electroencephalogram (EEG) measurements. Participants were exposed to various environments through Virtual Reality (VR), and significant differences were observed in the interactions within specific regions of the Visual and Dorsal Attention Networks. In the riverside setting, the restoration group demonstrated heightened perceptual engagement and more efficient attentional control. Additionally, a significant increase in global efficiency, a measure of brain network efficiency, was observed in the restoration group during soundscape exposure. These findings contribute to our understanding of the neural processes associated with the restorative effects of soundscapes, with implications for urban health and well-being strategies.

Association between gene expression and altered resting-state functional networks in type 2 diabetes

BackgroundType 2 diabetes (T2DM) is a polygenic metabolic disorder that accelerates brain aging and harms cognitive function. The underlying mechanism of T2DM-related brain functional changes has not been clarified.MethodsResting-fMRI data were obtained from 99 T2DM and 109 healthy controls (HCs). Resting-state functional connectivity networks (RSNs) were separated using the Independent Component Analysis (ICA) method, and functional connectivity (FC) differences between T2DM patients and HCs within the RSNs were detected. A partial least squares (PLS) regression was used to test the relation between gene expression from Allen Human Brain Atlas (AHBA) and intergroup FC differences within RSNs. Then the FC differences-related gene sets were enriched to determine the biological processes and pathways related to T2DM brain FC changes.ResultThe T2DM patients showed significantly increased FC in the left middle occipital gyrus (MOG) of the precuneus network (PCUN) and the right MOG / right precuneus of the dorsal attention network (DAN). FC differences within the PCUN were linked with the expression of genes enriched in the potassium channel and TrkB-Rac1 signaling pathways and biological processes related to synaptic function.ConclusionThis study linked FC and molecular alterations related to T2DM and suggested that the T2DM-related brain FC changes may have a genetic basis. This study hoped to provide a unique perspective to understand the biological substrates of T2DM-related brain changes.

Internal states as a source of subject-dependent movement variability are represented by large-scale brain networks

Humans’ ability to adapt and learn relies on reflecting on past performance. These experiences form latent representations called internal states that induce movement variability that improves how we interact with our environment. Our study uncovered temporal dynamics and neural substrates of two states from ten subjects implanted with intracranial depth electrodes while they performed a goal-directed motor task with physical perturbations. We identified two internal states using state-space models: one tracking past errors and the other past perturbations. These states influenced reaction times and speed errors, revealing how subjects strategize from trial history. Using local field potentials from over 100 brain regions, we found large-scale brain networks such as the dorsal attention and default mode network modulate visuospatial attention based on recent performance and environmental feedback. Notably, these networks were more prominent in higher-performing subjects, emphasizing their role in improving motor performance by regulating movement variability through internal states.

Left superior parietal lobe mediates the link between spontaneous mind-wandering tendency and task-switching performance

While increasing studies have documented the link between mind wandering and task switching, less is known about which brain regions mediate this relationship. Using the MPI-Leipzig Mind-Brain-Body dataset (N = 173), we investigated the association between trait-level tendencies of mind wandering, task-switching performance, structural connectivity, and resting-state functional connectivity. At the behavioral level, we found that higher spontaneous mind-wandering trait scores were associated with shorter reaction times on both repeat and switch trials. The whole brain cortical thickness analysis revealed a strong mediating role of the left superior parietal lobe, which is part of the dorsal attention network, in the link between spontaneous mind-wandering tendency and task-switching performance. The resting-state functional connectivity analysis further demonstrated that this association was partly mediated by the negative dorsal attention network-default mode network functional connectivity. No significant mediating effects were found for deliberate mind-wandering tendency. Overall, the findings highlight the pivotal role of the left superior parietal lobe in activating new mental set during mind-wandering and task-switching processes, providing another evidence in favor of a role for switching in mind wandering.

Effect of Meditation on Brain Activity during an Attention Task: A Comparison Study of ASL and BOLD Task fMRI.

Focused attention meditation (FAM) training has been shown to improve attention, but the neural basis of FAM on attention has not been thoroughly understood. Here, we aim to investigate the neural effect of a 2-month FAM training on novice meditators in a visual oddball task (a frequently adopted task to evaluate attention), evaluated with both ASL and BOLD fMRI. Using ASL, activation was increased in the middle cingulate (part of the salience network, SN) and temporoparietal (part of the frontoparietal network, FPN) regions; the FAM practice time was negatively associated with the longitudinal changes in activation in the medial prefrontal (part of the default mode network, DMN) and middle frontal (part of the FPN) regions. Using BOLD, the FAM practice time was positively associated with the longitudinal changes of activation in the inferior parietal (part of the dorsal attention network, DAN), dorsolateral prefrontal (part of the FPN), and precentral (part of the DAN) regions. The effect sizes for the activation changes and their association with practice time using ASL are significantly larger than those using BOLD. Our study suggests that FAM training may improve attention via modulation of the DMN, DAN, SN, and FPN, and ASL may be a sensitive tool to study the FAM effect on attention.

Aberrant brain intra- and internetwork functional connectivity in children with Prader-Willi syndrome

PurposePrader-Willi syndrome (PWS) suffers from brain functional reorganization and developmental delays during childhood, but the underlying neurodevelopmental mechanism is unclear. This paper aims to investigate the intra- and internetwork functional connectivity (FC) changes, and their relationships with developmental delays in PWS children.MethodsResting-state functional magnetic resonance imaging datasets of PWS children and healthy controls (HCs) were acquired. Independent component analysis was used to acquire core resting-state networks (RSNs). The intra- and internetwork FC patterns were then investigated.ResultsIn terms of intranetwork FC, children with PWS had lower FC in the dorsal attention network, the auditory network, the medial visual network (VN) and the sensorimotor network (SMN) than HCs (FWE-corrected, p < 0.05). In terms of internetwork FC, PWS children had decreased FC between the following pairs of regions: posterior default mode network (DMN) and anterior DMN; posterior DMN and SMN; SMN and posterior VN and salience network and medial VN (FDR-corrected, p < 0.05). Partial correlation analyses revealed that the intranetwork FC patterns were positively correlated with developmental quotients in PWS children, while the internetwork FC patterns were completely opposite (p < 0.05). Intranetwork FC patterns showed an area under the receiver operating characteristic curve of 0.947, with a sensitivity of 96.15% and a specificity of 81.25% for differentiating between PWS and HCs.ConclusionImpaired intra- and internetwork FC patterns in PWS children are associated with developmental delays, which may result from neural pathway dysfunctions. Intranetwork FC reorganization patterns can discriminate PWS children from HCs.Registration number on the Chinese Clinical Trail RegistryChiCTR2100046551.