Alteration of spontaneous brain activity in COPD patients

Functional connectivity alterations in the thalamus among patients with bronchial asthma

Objective

Bronchial Asthma (BA) is a common chronic respiratory disease worldwide. Earlier research has demonstrated abnormal functional connectivity (FC) in multiple cognition-related cortices in asthma patients. The thalamus (Thal) serves as a relay center for transmitting sensory signals, yet the modifications in the thalamic FC among individuals with asthma remain uncertain. This research employed the resting-state functional connectivity (rsFC) approach to explore alterations in thalamic functional connectivity among individuals with BA.

Patients and methods

After excluding participants who did not meet the criteria, this study finally included 31 patients with BA, with a gender distribution of 16 males and 15 females. Subsequently, we recruited 31 healthy control participants (HC) matched for age, gender, and educational background. All participants underwent the Montreal Cognitive Assessment (MoCA) and the Hamilton Depression Rating Scale (HAMD) assessment. Following this, both groups underwent head magnetic resonance imaging scans, and resting-state functional magnetic resonance imaging (rs-fMRI) data was collected. Based on the AAL (Automated Anatomical Labeling) template, the bilateral thalamic regions were used as seed points (ROI) for subsequent rsFC research. Pearson correlation analysis was used to explore the relationship between thalamic functional connectivity and neuropsychological scales in both groups. After controlling for potential confounding factors such as age, gender, intelligence, and emotional level, a two-sample t-test was further used to explore differences in thalamic functional connectivity between the two groups of participants.

Result

Compared to the HC group, the BA group demonstrated heightened functional connectivity (FC) between the left thalamus and the left cerebellar posterior lobe (CPL), left postcentral gyrus (PCG), and right superior frontal gyrus (SFG). Concurrently, there was a decrease in FC with both the Lentiform Nucleus (LN) and the left corpus callosum (CC). Performing FC analysis with the right thalamus as the Region of Interest (ROI) revealed an increase in FC between the right thalamus and the right SFG as well as the left CPL. Conversely, a decrease in FC was observed between the right thalamus and the right LN as well as the left CC.

Conclusion

In our study, we have verified the presence of aberrant FC patterns in the thalamus of BA patients. When compared to HCs, BA patients exhibit aberrant alterations in FC between the thalamus and various brain areas connected to vision, hearing, emotional regulation, cognitive control, somatic sensations, and wakefulness. This provides further confirmation of the substantial role played by the thalamus in the advancement of BA.

The Abnormal Alternations of Brain Imaging in Patients with Chronic Obstructive Pulmonary Disease: A Systematic Review

Background

Cognitive impairment (CI) is an important extrapulmonary complication in patients with chronic obstructive pulmonary disease (COPD). Multimodal Neuroimaging Examination can display changes in brain structure and functions in patients with COPD.

Objective

The purpose of this systematic review is to provide an overview of the variations in brain imaging in patients with COPD and their potential relationship with CI. Furthermore, we aim to provide new ideas and directions for future research.

Methods

Literature searches were performed using the electronic databases PubMed, Scopus, and ScienceDirect. All articles published between January 2000 and November 2021 that met the eligibility criteria were included.

Results

Twenty of the 23 studies focused on changes in brain structure and function. Alterations in the brain's macrostructure are manifested in the bilateral frontal lobe, hippocampus, right temporal lobe, motor cortex, and supplementary motor area. The white matter microstructural changes initially appear in the bilateral frontal subcortical region. Regarding brain function, patients with COPD exhibited reduced frontal cerebral perfusion and abnormal alterations in intrinsic brain activity in the bilateral posterior cingulate cortex, precuneus, right lingual gyrus, and left anterior central gyrus. Currently, there is limited research related to brain networks.

Conclusion

CI in patients with COPD may present as a type of dementia different from Alzheimer's disease, which tends to manifest as frontal cognitive decline early in the disease. Further studies are required to clarify the neurobiological pathways of CI in patients with COPD from the perspective of brain connectomics based on the whole-brain system in the future.

The adjusted impact of different severities of acute exacerbations and medications on the risk of developing dementia in COPD patients

BACKGROUND

Although a relationship between chronic obstructive pulmonary disease (COPD) and dementia has been reported, the initial severity upon emergency department (ED) visits and the medications used have not been well evaluated as risk factors for increased dementia occurrence. We aimed to analyze the risks of dementia development over 5 years among patients with COPD compared to matched controls (primary) and the impact of different severities of acute exacerbations (AEs) of COPD and medications on the risk of dementia development among COPD patients (secondary).

METHOD

This study used the Taiwanese government deidentified health care database. We enrolled patients during the 10-year study period (January 1, 2000, to December 31, 2010), and each patient was followed up for 5 years. Once these patients received a diagnosis of dementia or died, they were no longer followed up. The study group included 51,318 patients who were diagnosed with COPD and 51,318 matched (in terms of age, sex, and the number of hospital visits) non-COPD patients from the remaining patients as the control group. Each patient was followed up for 5 years to analyze the risk of dementia with Cox regression analysis. Data on medications (antibiotics, bronchodilators, corticosteroids) and severity at the initial ED visit (ED treatment only, hospital admission, or ICU admission) were collected for both groups, as well as demographics and baseline comorbidities, which were considered confounding factors.

RESULTS

In the study and control groups, 1,025 (2.0%) and 423 (0.8%) patients suffered from dementia, respectively. The unadjusted HR for dementia was 2.51 (95% CI: 2.24-2.81) in the study group. Bronchodilator treatment was associated with the HRs, especially among those who received long-term (> 1 month) treatment (HR = 2.10, 95% CI: 1.91-2.45). Furthermore, among 3,451 AE of COPD patients who initially visited the ED, patients who required ICU admission (n = 164, 4.7%) had a higher risk of dementia occurrence (HR = 11.05, 95% CI: 7.77-15.71).

CONCLUSION

Bronchodilator administration might be associated with a decreased risk of dementia development. More importantly, patients who suffered AEs of COPD and initially visited the ED and required ICU admission had a higher risk of developing dementia.

Cerebral neurovascular alterations in stable chronic obstructive pulmonary disease: a preliminary fMRI study

Purpose

Cognitive impairment (CI) is very common in patients with chronic obstructive pulmonary disease (COPD). Cerebral structural and functional abnormalities have been reported in cognitively impaired patients with COPD, and the neurovascular coupling changes are rarely investigated. To address this issue, arterial spin labeling (ASL) and resting-state blood oxygenation level dependent (BOLD) fMRI techniques were used to determine whether any neurovascular changes in COPD patients.

Methods

Forty-five stable COPD patients and forty gender- and age-matched healthy controls were recruited. Furthermore, resting-state BOLD fMRI and ASL were acquired to calculate degree centrality (DC) and cerebral blood flow (CBF) respectively. The CBF-DC coupling and CBF/DC ratio were compared between the two groups.

Results

COPD patients showed abnormal CBF, DC and CBF/DC ratio in several regions. Moreover, lower CBF/DC ratio in the left lingual gyrus negatively correlated with naming scores, lower CBF/DC ratio in medial frontal cortex/temporal gyrus positively correlated with the Montreal Cognitive Assessment (MoCA), visuospatial/executive and delayed recall scores.

Conclusion

These findings may provide new potential insights into neuropathogenesis of cognition decline in stable COPD patients.

Abnormal static and dynamic functional network connectivity in stable chronic obstructive pulmonary disease

Objective

Many studies have explored the neural mechanisms of cognitive impairment in chronic obstructive pulmonary disease (COPD) patients using the functional MRI. However, the dynamic properties of brain functional networks are still unclear. The purpose of this study was to explore the changes in dynamic functional network attributes and their relationship with cognitive impairment in stable COPD patients.

Materials and methods

The resting-state functional MRI and cognitive assessments were performed on 19 stable COPD patients and 19 age-, sex-, and education-matched healthy controls (HC). We conducted the independent component analysis (ICA) method on the resting-state fMRI data, and obtained seven resting-state networks (RSNs). After that, the static and dynamic functional network connectivity (sFNC and dFNC) were respectively constructed, and the differences of functional connectivity (FC) were compared between the COPD patients and the HC groups. In addition, the correlation between the dynamic functional network attributes and cognitive assessments was analyzed in COPD patients.

Results

Compared to HC, there were significant differences in sFNC among COPD patients between and within networks. COPD patients showed significantly longer mean dwell time and higher fractional windows in weaker connected State I than that in HC. Besides, in comparison to HC, COPD patients had more extensive abnormal FC in weaker connected State I and State IV, and less abnormal FC in stronger connected State II and State III, which were mainly located in the default mode network, executive control network, and visual network. In addition, the dFNC properties including mean dwell time and fractional windows, were significantly correlated with some essential clinical indicators such as FEV₁, FEV₁/FVC, and c-reactive protein (CRP) in COPD patients.

Conclusion

These findings emphasized the differences in sFNC and dFNC of COPD patients, which provided a new perspective for understanding the cognitive neural mechanisms, and these indexes may serve as neuroimaging biomarkers of cognitive performance in COPD patients.

Abnormal intrinsic functional hubs and connectivity in stable patients with COPD: a resting-state MRI study

Chronic obstructive pulmonary disease (COPD) affects a large population and is closely associated with cognitive impairment. However, the mechanisms of cognitive impairment in COPD patients have not been unraveled. This study investigated the change in patterns of intrinsic functional hubs using a degree centrality (DC) analysis. The connectivity between these abnormal hubs with the remaining brain was also investigated using functional connectivity (FC). Nineteen stable patients with COPD and 20 normal controls(NC) underwent functional magnetic resonance imaging (MRI) examinations and clinical and neuropsychologic assessments. We measured the voxel-wise DC across the whole brain gray matter and the seed-based FC between these abnormal hubs in the remaining brain matter; the group difference was calculated. A partial correlation analysis was performed to assess the relationship between the abnormal DC and clinical variables in COPD patients. Compared to NC, the patients with COPD exhibited significantly decreased DC in the right lingual gyrus (LG), bilateral supplementary motor area (SMA), and right paracentral lobule (PCL). A further seed-based FC analysis found that COPD patients demonstrated significantly decreased FC between these abnormal hubs in several brain areas, including the left cerebellum anterior lobe, left lingual gyrus, left fusiform gyrus, right insula, right inferior frontal gyrus, limbic lobe, cingulate gyrus, left putamen, lentiform nucleus, right precuneus, and right paracentral lobule. A partial correlation analysis showed that the decreased DC in the right PCL was positively correlated with the FEV1 and FEV1/FVC, and the decreased DC in the SMA was positively correlated with naming and pH in COPD patients. This study demonstrates that there are intrinsic functional hubs and connectivity alterations that may reflect the aberrant information communication in the brain of COPD patients. These findings may help provide new insight for understanding the mechanisms of COPD-related cognitive impairment from whole brain functional connections.

Intrinsic low-frequency oscillation changes in multiple-frequency bands in stable patients with chronic obstructive pulmonary disease

Abnormal local spontaneous brain activity during the resting state has been observed in chronic obstructive pulmonary disease (COPD). However, it is still largely unclear whether the abnormalities are related to specific frequency bands. Our purpose was to explore intrinsic neural activity changes in different frequency bands by using the amplitude of low-frequency fluctuation (ALFF) method in stable COPD patients. Nineteen stable COPD patients and twenty gender-, age- and education-matched normal controls (NCs) underwent functional magnetic resonance imaging scans, cognitive function tests and lung function tests. Two different frequency bands (slow-4: 0.027-0.073 Hz; slow-5: 0.01-0.027 Hz) were calculated and analyzed for frequency-dependent intrinsic neural activity by using the ALFF method. A two-way analysis of variance test was used to compare the main effects of the groups and the frequency bands in the ALFF method. Further post-hoc t-tests were used to compare the differences between COPD patients and NCs in terms of the different frequency bands. A Pearson's correlation analysis was performed to explore the relationship between the altered ALFF brain areas in the different frequency bands and the clinical evaluations in the COPD patients. There were main effects of the groups including significantly higher ALFF values in the right superior temporal gyrus (STG), the bilateral cerebellum posterior lobe (CPL), the right lingual gyrus (LG) and the right brainstem, and as well as significantly decreased ALFF values in the right inferior parietal lobule (IPL) and the angular. The main effect of frequency was demonstrated in the CPL, the STG, the prefrontal cortex and the middle cingulate gyrus. Furthermore, COPD patients exhibited more widespread alterations in intrinsic brain activity in the slow-5 band than in the slow-4 band. Moreover, the abnormal intrinsic brain activity in the slow-4 and slow-5 bands were associated with PaCO₂ in COPD patients. These current results indicated that COPD patients showed abnormal intrinsic brain activity in two different frequency bands, and abnormal intrinsic neuronal activity in different brain regions could be better detected by slow-5 band. These observations may provide a neoteric view into understanding the local neural psychopathology in stable COPD patients.

Alterations of grey matter volumes and network-level functions in patients with stable chronic obstructive pulmonary disease

OBJECTIVE

The purpose of this study was to investigate structural and functional alterations of the brain in the patients with stable chronic obstructive pulmonary disorder (COPD) and further investigate how these alterations correlated to parameters of pulmonary function test, cognitive function and disease duration in patients with COPD.

METHOD

Forty-five patients with stable COPD and forty age- and gender-matched healthy controls were enrolled into this study. Both resting-state fMRI and structural MRI were acquired for each participant. Voxel-based morphology was utilized to analyze alterations of the grey matter volume (GMV), and the seed-based resting-state functional connectivity (FC) was used to evaluate the network-level functional alterations.

RESULTS

Compared to healthy controls, patients with stable COPD showed decreased GMV in the left supramarginal gyrus/precentral gyrus (SMG/PreCG), bilateral posterior midcingulate cortex (pMCC), right middle occipital gyrus (MOG) and right SMG. Furthermore, COPD patients mainly showed decreased FC within the visual network, frontoparietal network and other brain regions. Subsequent correlational analyses revealed that the decreased FC within visual network, frontoparietal network were positively correlated with the Montreal Cognitive Assessment score, language-domain score, attention-domain score and disease duration in patients with COPD.

CONCLUSION

Our findings provided evidence that COPD patients showed decreased GMV and regional and network-level functional alterations within the visual network, frontoparietal network and other networks. We speculated that atrophic GMV and FC of visual network and frontoparietal network are involved in the neural mechanism of mild cognitive impairment in stable COPD patients.

Disrupted resting-state spontaneous neural activity in stable COPD

Introduction and aim

Abnormal brain structure and function in COPD has been reported on MRI. However, the deficit in local synchronization of spontaneous activity in patients with stable COPD remains unknown. The main aim of the present study was to explore spontaneous brain activity in patients with COPD compared with normal controls using the regional homogeneity (ReHo) method based on resting-state functional MRI.

Methods

Nineteen patients with stable COPD and 20 well-matched (including age, sex, and number of years of education) normal controls who were recruited for the present study underwent resting-state functional MRI examinations and a series of neuropsychological and clinical assessments. The ReHo method was used to assess the strength of local brain signal synchrony. The mean ReHo values in brain areas with abnormal ReHo were evaluated with a receiver operating characteristic curve. The relationships between the brain regions with altered ReHo values and the clinical and neuropsychological parameters in COPD patients were assessed using Pearson’s correlation.

Results

Patients with COPD showed significantly lower ReHo values in the left occipital lobe and the right lingual, bilateral precuneus, and right precentral gyrus. The result of receiver operating characteristic curve analysis showed that the altered average ReHo values have high efficacy for distinguishing function. The mean lower ReHo values in the precuneus gyrus showed a significant positive correlation with FEV₁%, FEV₁/FVC, and orientation function but a significant negative correlation with arterial partial pressure of carbon dioxide.

Conclusion

The COPD patients demonstrated abnormal synchrony of regional spontaneous activity, and the regions with abnormal activity were all correlated with visual processing pathways, which might provide us with a new perspective to further understand the underlying pathophysiology of cognitive impairment in patients with COPD.

Alterations of the default mode network and cognitive impairments in patients with chronic obstructive pulmonary disease

Background and objectives

Cognitive impairment is a common extrapulmonary comorbidity in COPD patients. The default mode network (DMN) plays a critical role in maintaining the normal activities of humans, and its function can be evaluated by resting state functional magnetic resonance imaging. The aim of this study was to investigate the correlations between cognition and function changes of the DMN in COPD patients.

Methods

One hundred and thirteen eligible participants including 30 control subjects and 83 COPD patients matched for demographic characteristics were recruited. All participants performed cognitive function tests and underwent resting state functional magnetic resonance imaging.

Results

The total cognitive function scores of COPD patients were significantly different from those of control subjects (P<0.05) and worsened with the degree of airflow obstruction. The activated brain regions in the DMN of COPD patients were less than those of normal controls. Six activated brain regions in the DMN were found to develop significantly different functional connectivity (FC) values among the subjects. Meanwhile, the FC values of the left posterior cingulate cortex and left hippocampus correlated well with cognitive functions and pulmonary function.

Conclusion

COPD patients have cognitive impairments that correlate well with disease severity. FC changes in activated brain regions in the DMN may predict cognitive impairment, and the left posterior cingulate cortex and left hippocampus may be important brain regions related to cognitive impairment in COPD patients.

Abnormal intrinsic brain activities in stable patients with COPD: a resting-state functional MRI study

OBJECTIVE

The majority of previous neuroimaging studies have reported both structural and functional changes in COPD, whereas the intrinsic low-frequency oscillations changes and the relationship between the abnormal brain regions and the clinical performances remain unknown. The present study was conducted with the aim of evaluating the intrinsic brain activity in COPD patients using the amplitude of low-frequency fluctuation (ALFF) method.

METHODS

All participants, including 19 stable patients with COPD and 20 normal controls (NCs) matched in age, sex, and education, underwent resting-state functional MRI scans and performed cognitive function tests and respiratory functions tests. The local spontaneous brain activity was examined using the voxel-wise ALFF. Pearson's correlation analysis was used to investigate the relationships between the brain regions with altered ALFF signal values and the clinical features in COPD patients.

RESULTS

Compared with the NCs, COPD patients showed significantly lower cognitive function scores. Also, lower ALFF areas in the cluster of the posterior cingulate cortex (PCC) and precuneus, as well as a higher ALFF area in the brainstem were also found in COPD patients. The mean ALFF values in the PCC, precuneus, and brainstem showed high sensitivity and specificity in operating characteristic curves analysis, which might have the ability to distinguish COPD from NCs. Meanwhile, the mean signal values of the lower ALFF cluster displayed significant positive correlations with FEV₁/FVC proportion and significant negative correlation with PaCO₂; the higher ALFF cluster showed significant positive correlation with FEV₁ proportion in COPD.

CONCLUSION

According to the results of the present study, the COPD patients showed abnormal intrinsic brain activities in the precuneus, PCC, and brainstem, which might provide useful information to better understand the underlying pathophysiology of cognitive impairment.

Mechanism of Cerebralcare Granule® for Improving Cognitive Function in Resting-State Brain Functional Networks of Sub-healthy Subjects

Cerebralcare Granule® (CG), a Chinese herbal medicine, has been used to ameliorate cognitive impairment induced by ischemia or mental disorders. The ability of CG to improve health status and cognitive function has drawn researchers' attention, but the relevant brain circuits that underlie the ameliorative effects of CG remain unclear. The present study aimed to explore the underlying neurobiological mechanisms of CG in ameliorating cognitive function in sub-healthy subjects using resting-state functional magnetic resonance imaging (fMRI). Thirty sub-healthy participants were instructed to take one 2.5-g package of CG three times a day for 3 months. Clinical cognitive functions were assessed with the Chinese Revised Wechsler Adult Intelligence Scale (WAIS-RC) and Wechsler Memory Scale (WMS), and fMRI scans were performed at baseline and the end of intervention. Functional brain network data were analyzed by conventional network metrics (CNM) and frequent subgraph mining (FSM). Then 21 other sub-healthy participants were enrolled as a blank control group of cognitive functional. We found that administrating CG can improve the full scale of intelligence quotient (FIQ) and Memory Quotient (MQ) scores. At the same time, following CG treatment, in CG group, the topological properties of functional brain networks were altered in various frontal, temporal, occipital cortex regions, and several subcortical brain regions, including essential components of the executive attention network, the salience network, and the sensory-motor network. The nodes involved in the FSM results were largely consistent with the CNM findings, and the changes in nodal metrics correlated with improved cognitive function. These findings indicate that CG can improve sub-healthy subjects' cognitive function through altering brain functional networks. These results provide a foundation for future studies of the potential physiological mechanism of CG.