Genetic Basis and Evolution of Structural Color Polymorphism in an Australian Songbird.

Island organisms often evolve phenotypes divergent from their mainland counterparts, providing a useful system for studying adaptation under differential selection. In the white-winged fairywren (Malurus leucopterus), subspecies on two islands have a black nuptial plumage whereas the subspecies on the Australian mainland has a blue nuptial plumage. The black subspecies have a feather nanostructure that could in principle produce a blue structural color, suggesting a blue ancestor. An earlier study proposed independent evolution of melanism on the islands based on the history of subspecies divergence. However, the genetic basis of melanism and the origin of color differentiation in this group are still unknown. Here, we used whole-genome resequencing to investigate the genetic basis of melanism by comparing the blue and black M. leucopterus subspecies to identify highly divergent genomic regions. We identified a well-known pigmentation gene ASIP and four candidate genes that may contribute to feather nanostructure development. Contrary to the prediction of convergent evolution of island melanism, we detected signatures of a selective sweep in genomic regions containing ASIP and SCUBE2 not in the black subspecies but in the blue subspecies, which possesses many derived SNPs in these regions, suggesting that the mainland subspecies has re-evolved a blue plumage from a black ancestor. This proposed re-evolution was likely driven by a preexisting female preference. Our findings provide new insight into the evolution of plumage coloration in island versus continental populations, and, importantly, we identify candidate genes that likely play roles in the development and evolution of feather structural coloration.

Development and validation of a perivascular space segmentation method in multi-center datasets.

BACKGROUND: Perivascular spaces (PVS) visible on magnetic resonance imaging (MRI) are significant markers associated with various neurological diseases. Although quantitative analysis of PVS may enhance sensitivity and improve consistency across studies, the field lacks a universally validated method for analyzing images from multi-center studies. METHODS: We annotated PVS on multi-center 3D T1-weighted (T1w) images acquired using scanners from three major vendors (Siemens, General Electric, and Philips). A neural network, mcPVS-Net (multi-center PVS segmentation network), was trained using data from 40 subjects and then tested in a separate cohort of 15 subjects. We assessed segmentation accuracy against ground truth masks tailored for each scanner vendor. Additionally, we evaluated the agreement between segmented PVS volumes and visual scores for each scanner. We also explored correlations between PVS volumes and various clinical factors such as age, hypertension, and white matter hyperintensities (WMH) in a larger sample of 1020 subjects. Furthermore, mcPVS-Net was applied to a new dataset comprising both T1w and T2-weighted (T2w) images from a United Imaging scanner to investigate if PVS volumes could discriminate between subjects with differing visual scores. We also compared the mcPVS-Net with a previously published method that segments PVS from T1 images. RESULTS: In the test dataset, mcPVS-Net achieved a mean DICE coefficient of 0.80, with an average Precision of 0.81 and Recall of 0.79, indicating good specificity and sensitivity. The segmented PVS volumes were significantly associated with visual scores in both the basal ganglia (r = 0.541, p < 0.001) and white matter regions (r = 0.706, p < 0.001), and PVS volumes were significantly different among subjects with varying visual scores. Segmentation performance was consistent across different scanner vendors. PVS volumes exhibited significant associations with age, hypertension, and WMH. In the United Imaging scanner dataset, PVS volumes showed good associations with PVS visual scores evaluated on either T1w or T2w images. Compared to a previously published method, mcPVS-Net showed a higher accuracy and improved PVS segmentation in the basal ganglia region. CONCLUSION: The mcPVS-Net demonstrated good accuracy for segmenting PVS from 3D T1w images. It may serve as a useful tool for future PVS research.

Higher intracranial arterial pulsatility is associated with presumed imaging markers of the glymphatic system: An explorative study.

BACKGROUND: Arterial pulsation has been suggested as a key driver of paravascular cerebrospinal fluid flow, which is the foundation of glymphatic clearance. However, whether intracranial arterial pulsatility is associated with glymphatic markers in humans has not yet been studied. METHODS: Seventy-three community participants were enrolled in the study. 4D phase-contrast magnetic resonance imaging (MRI) was used to quantify the hemodynamic parameters including flow pulsatility index (PIflow) and area pulsatility index (PIarea) from 13 major intracerebral arterial segments. Three presumed neuroimaging markers of the glymphatic system were measured: including dilation of perivascular space (PVS), diffusivity along the perivascular space (ALPS), and volume fraction of free water (FW) in white matter. We explored the relationships between PIarea, PIflow, and the presumed glymphatic markers, controlling for related covariates. RESULTS: PIflow in the internal carotid artery (ICA) C2 segment (OR, 1.05; 95 % CI, 1.01-1.10, per 0.01 increase in PI) and C4 segment (OR, 1.05; 95 % CI, 1.01-1.09) was positively associated with the dilation of basal ganglia PVS, and PIflow in the ICA C4 segment (OR, 1.06, 95 % CI, 1.02-1.10) was correlated with the dilation of PVS in the white matter. ALPS was associated with PIflow in the basilar artery (ß, -0.273, p, 0.046) and PIarea in the ICA C2 (ß, -0.239, p, 0.041) and C7 segments (ß, -0.238, p, 0.037). CONCLUSIONS: Intracranial arterial pulsatility was associated with presumed neuroimaging markers of the glymphatic system, but the results were not consistent across different markers. Further studies are warranted to confirm these findings.

Microstructural alterations of the hypothalamus in Parkinson's disease and probable REM sleep behavior disorder.

BACKGROUND: Whether there is hypothalamic degeneration in Parkinson's disease (PD) and its association with clinical symptoms and pathophysiological changes remains controversial. OBJECTIVES: We aimed to quantify microstructural changes in hypothalamus using a novel deep learning-based tool in patients with PD and those with probable rapid-eye-movement sleep behavior disorder (pRBD). We further assessed whether these microstructural changes associated with clinical symptoms and free thyroxine (FT4) levels. METHODS: This study included 186 PD, 67 pRBD, and 179 healthy controls. Multi-shell diffusion MRI were scanned and mean kurtosis (MK) in hypothalamic subunits were calculated. Participants were assessed using Unified Parkinson's Disease Rating Scale (UPDRS), RBD Questionnaire-Hong Kong (RBDQ-HK), Hamilton Depression Rating Scale (HAMD), and Activity of Daily Living (ADL) Scale. Additionally, a subgroup of PD (n = 31) underwent assessment of FT4. RESULTS: PD showed significant decreases of MK in anterior-superior (a-sHyp), anterior-inferior (a-iHyp), superior tubular (supTub), and inferior tubular hypothalamus when compared with healthy controls. Similarly, pRBD exhibited decreases of MK in a-iHyp and supTub. In PD group, MK in above four subunits were significantly correlated with UPDRS-I, HAMD, and ADL. Moreover, MK in a-iHyp and a-sHyp were significantly correlated with FT4 level. In pRBD group, correlations were observed between MK in a-iHyp and UPDRS-I. CONCLUSIONS: Our study reveals that microstructural changes in the hypothalamus are already significant at the early neurodegenerative stage. These changes are associated with emotional alterations, daily activity levels, and thyroid hormone levels.

Hyperfractionation compared with standard fractionation in intensity-modulated radiotherapy for patients with locally advanced recurrent nasopharyngeal carcinoma: a multicentre, randomised, open-label, phase 3 trial.

BACKGROUND: Reirradiation in standard fractionation for locally advanced recurrent nasopharyngeal carcinoma after a previous course of high-dose radiotherapy is often associated with substantial late toxicity, negating its overall benefit. We therefore aimed to investigate the efficacy and safety of hyperfractionation compared with standard fractionation in intensity-modulated radiotherapy. METHODS: This multicentre, randomised, open-label, phase 3 trial was done in three centres in Guangzhou, China. Eligible patients were aged 18-65 years with histopathologically confirmed undifferentiated or differentiated, non-keratinising, advanced locally recurrent nasopharyngeal carcinoma. Participants were randomly assigned (1:1) to either receive hyperfractionation (65 Gy in 54 fractions, given twice daily with an interfractional time interval of at least 6 h) or standard fractionation (60 Gy in 27 fractions, given once a day). Intensity-modulated radiotherapy was used in both groups. A computer program generated the assignment sequence and randomisation was stratified by treatment centre, recurrent tumour stage (T2-T3 vs T4), and recurrent nodal stage (N0 vs N1-N2), determined at the time of randomisation. The two primary endpoints were the incidence of severe late complications defined as the incidence of grade 3 or worse late radiation-induced complications occurring 3 months after the completion of radiotherapy until the latest follow-up in the safety population, and overall survival defined as the time interval from randomisation to death due to any cause in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT02456506. FINDINGS: Between July 10, 2015, and Dec 23, 2019, 178 patients were screened for eligibility, 144 of whom were enrolled and randomly assigned to hyperfractionation or standard fractionation (n=72 in each group). 35 (24%) participants were women and 109 (76%) were men. After a median follow-up of 45·0 months (IQR 37·3-53·3), there was a significantly lower incidence of grade 3 or worse late radiation-induced toxicity in the hyperfractionation group (23 [34%] of 68 patients) versus the standard fractionation group (39 [57%] of 68 patients; between-group difference -23% [95% CI -39 to -7]; p=0·023). Patients in the hyperfractionation group had better 3-year overall survival than those in the standard fractionation group (74·6% [95% CI 64·4 to 84·8] vs 55·0% [43·4 to 66·6]; hazard ratio for death 0·54 [95% CI 0·33 to 0·88]; p=0·014). There were fewer grade 5 late complications in the hyperfractionation group (five [7%] nasal haemorrhage) than in the standard fractionation group (16 [24%], including two [3%] nasopharyngeal necrosis, 11 [16%] nasal haemorrhage, and three [4%] temporal lobe necrosis). INTERPRETATION: Hyperfractionated intensity-modulated radiotherapy could significantly decrease the rate of severe late complications and improve overall survival among patients with locally advanced recurrent nasopharyngeal carcinoma. Our findings suggest that hyperfractionated intensity-modulated radiotherapy could be used as the standard of care for these patients. FUNDING: Key-Area Research and Development of Guangdong Province, the National Natural Science Foundation of China, the Special Support Program for High-level Talents in Sun Yat-sen University Cancer Center, the Guangzhou Science and Technology Plan Project, and the National Ten Thousand Talents Program Science and Technology Innovation Leading Talents, Sun Yat-Sen University Clinical Research 5010 Program.

Small vessel disease and cognitive reserve oppositely modulate global network redundancy and cognitive function: A study in middle-to-old aged community participants.

Cerebral small vessel disease (SVD) can disrupt the global brain network and lead to cognitive impairment. Conversely, cognitive reserve (CR) can improve one's cognitive ability to handle damaging effects like SVD, partly by optimizing the brain network's organization. Understanding how SVD and CR collectively influence brain networks could be instrumental in preventing cognitive impairment. Recently, brain redundancy has emerged as a critical network protective metric, providing a nuanced perspective of changes in network organization. However, it remains unclear how SVD and CR affect global redundancy and subsequently cognitive function. Here, we included 121 community-dwelling participants who underwent neuropsychological assessments and a multimodal MRI examination. We visually examined common SVD imaging markers and assessed lifespan CR using the Cognitive Reserve Index Questionnaire. We quantified the global redundancy index (RI) based on the dynamic functional connectome. We then conducted multiple linear regressions to explore the specific cognitive domains related to RI and the associations of RI with SVD and CR. We also conducted mediation analyses to explore whether RI mediated the relationships between SVD, CR, and cognition. We found negative correlations of RI with the presence of microbleeds (MBs) and the SVD total score, and a positive correlation of RI with leisure activity-related CR (CRI-leisure). RI was positively correlated with memory and fully mediated the relationships between the MBs, CRI-leisure, and memory. Our study highlights the potential benefits of promoting leisure activities and keeping brain redundancy for memory preservation in older adults, especially those with SVD.

An Investigation of Cerebral Vascular Functional Properties in Middle-to-Old Age Community People With High Vascular Risk Profiles.

BACKGROUND: Vascular degeneration is an important cause of brain damage in aging. Assessing the functional properties of the cerebral vascular system may aid early diagnosis and prevention. PURPOSE: To investigate the relationships between potential vascular functional markers and vascular risks, brain parenchymal damage, and cognition. STUDY TYPE: Retrospective. SUBJECTS: Two hundred two general community subjects (42-80 years, males/females: 127/75). FIELD STRENGTH/SEQUENCE: 3 T, spin echo T1W/T2W/FLAIR, resting-state functional MRI with an echo-planar sequence (rsfMRI), pseudo-continuous arterial spin labeling (pCASL) with a three-dimensional gradient-spin echo sequence. ASSESSMENT: Cerebral blood flow (CBF) in gray matter calculated using pCASL, blood transit times calculated using rsfMRI, and the SD of internal carotid arteries signal (ICAstd) calculated using rsfMRI; visual assessment for lacunes; quantification of white matter hyperintensity volume; permutation test for quality control; collection of demographic and clinical data, Montreal Cognitive Assessment, Mini-Mental State Examination. STATISTICAL TESTS: Kolmogorov-Smirnov test; Spearman rank correlation analysis; Multivariable linear regression analysis controlling for covariates; The level of statistical significance was set at P < 0.05. RESULTS: Age was negatively associated with ICAstd (ß = -0.180). Diabetes was associated with longer blood transit time from large arteries to capillary bed (ß = 0.185, adjusted for age, sex, and intracranial volume). Larger ICAstd was associated with less presence of lacunes (odds ratio: 0.418, adjusted for age and sex). Higher gray matter CBF (ß = 0.154) and larger ICAstd (ß = 0.136) were associated with better MoCA scores (adjusted for age, sex, and education). DATA CONCLUSION: Prolonged blood transit time, decreased ICAstd, and diminished CBF were associated with vascular dysfunction and cognitive impairment. They may serve as vascular functional markers in future studies. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 3.

Glymphatic system dysfunction and risk of clinical milestones in patients with Parkinson disease.

BACKGROUND AND PURPOSE: Glymphatic dysfunction may play a significant role in the development of neurodegenerative diseases. We aimed to evaluate the association between glymphatic dysfunction and the risk of malignant event/clinical milestones in Parkinson disease (PD). METHODS: This study included 236 patients from August 2014 to December 2020. Diffusion tensor imaging analysis along the perivascular space (DTI-ALPS) index was calculated as an approximate measure of glymphatic function. The primary outcomes were four clinical milestones including recurrent falls, wheelchair dependence, dementia, and placement in residential or nursing home care. The associations of DTI-ALPS with the risk of clinical milestones were examined using multivariate Cox proportional hazards regression models. Then, logistic regression was repeated using clinical variables and DTI-ALPS index individually and in combination of the two to explore the ability to distinguish patients who reached clinical milestones within a 5-year period. RESULTS: A total of 175 PD patients with baseline DTI-ALPS index and follow-up clinical assessments were included. A lower DTI-ALPS was independently associated with increased risk of recurrent falls, wheelchair dependence, and dementia. Additionally, in 103 patients monitored over 5 years, a logistic regression model combining clinical variables and DTI-ALPS index showed better performance for predicting wheelchair dependence within 5 years than a model using clinical variables or DTI-ALPS index alone. CONCLUSIONS: Glymphatic dysfunction, as measured by the DTI-ALPS index, was associated with increased risk of clinical milestones in patients with PD. This finding implies that therapy targeting the glymphatic system may serve as a viable strategy for slowing down the progression of PD.

Cholinergic basal forebrain system degeneration underlies postural instability/gait difficulty and attention impairment in Parkinson's disease.

BACKGROUND AND PURPOSE: The specific pathophysiological mechanisms underlying postural instability/gait difficulty (PIGD) and cognitive function in Parkinson's disease (PD) remain unclear. Both postural and gait control, as well as cognitive function, are associated with the cholinergic basal forebrain (cBF) system. METHODS: A total of 84 PD patients and 82 normal controls were enrolled. Each participant underwent motor and cognitive assessments. Diffusion tensor imaging was used to detect structural abnormalities in the cBF system. The cBF was segmented using FreeSurfer, and its fiber tract was traced using probabilistic tractography. To provide information on extracellular water accumulation, free-water fraction (FWf) was quantified. FWf in the cBF and its fiber tract, as well as cortical projection density, were extracted for statistical analyses. RESULTS: Patients had significantly higher FWf in the cBF (p < 0.001) and fiber tract (p = 0.021) than normal controls, as well as significantly lower cBF projection in the occipital (p < 0.001), parietal (p < 0.001) and prefrontal cortex (p = 0.005). In patients, a higher FWf in the cBF correlated with worse PIGD score (r = 0.306, p = 0.006) and longer Trail Making Test A time (r = 0.303, p = 0.007). Attentional function (Trail Making Test A) partially mediated the association between FWf in the cBF and PIGD score (indirect effect, a*b = 0.071; total effect, c = 0.256; p = 0.006). CONCLUSIONS: Our findings suggest that degeneration of the cBF system in PD, from the cBF to its fiber tract and cortical projection, plays an important role in cognitive-motor interaction.

"Building bridges"-communication education for residents in radiology: a scoping review.

BACKGROUND: Good communication is an important professional attribute for radiologists. However, explorations of communication education and their outcomes in radiology residents are sparse. This scoping review aims to evaluate the existing literature on communication education for radiology residents, identify gaps in current practices, and suggest directions for future studies. METHODS: A scoping review following the six-step approach of Arksey and O'Malley was undertaken. We searched through PubMed, Embase, ERIC, and Web of Science databases, focusing on communication education in radiology residents. RESULTS: Sixteen of the 3096 identified articles were included in the analysis. Most studies (13/16) originated from the United States. The studies varied in study design, including quantitative, qualitative and mixed-methods approaches. The sample sizes of most studies were small to moderate, with more than half of the studies had fewer than 30 participants. The identified studies predominantly focused on communication with patients and healthcare professionals. The need for communication education, the efficacy of specific communication education programs, and the capability of some assessment tools for evaluating residents' communication skills were investigated. CONCLUSIONS: This scoping review reveals the gap between the need for communication education and the lack of comprehensive education programs in radiology residents globally. Future studies should develop tailored interventions and use reliable assessment tools, engaging more participants with extended follow-up periods, and expand the scope of communication training to include all relevant stakeholders.

Role of chemotherapy in patients with nasopharynx carcinoma treated with radiotherapy (MAC-NPC): an updated individual patient data network meta-analysis.

BACKGROUND: The meta-analysis of chemotherapy for nasopharynx carcinoma (MAC-NPC) collaborative group previously showed that the addition of adjuvant chemotherapy to concomitant chemoradiotherapy had the highest survival benefit of the studied treatment regimens in nasopharyngeal carcinoma. Due to the publication of new trials on induction chemotherapy, we updated the network meta-analysis. METHODS: For this individual patient data network meta-analysis, trials of radiotherapy with or without chemotherapy in patients with non-metastatic nasopharyngeal carcinoma that completed accrual before Dec 31, 2016, were identified and updated individual patient data were obtained. Both general databases (eg, PubMed and Web of Science) and Chinese medical literature databases were searched. Overall survival was the primary endpoint. A frequentist network meta-analysis approach with a two-step random effect stratified by trial based on hazard ratio Peto estimator was used. Global Cochran Q statistic was used to assess homogeneity and consistency, and p score to rank treatments, with higher scores indicating higher benefit therapies. Treatments were grouped into the following categories: radiotherapy alone, induction chemotherapy followed by radiotherapy, induction chemotherapy without taxanes followed by chemoradiotherapy, induction chemotherapy with taxanes followed by chemoradiotherapy, chemoradiotherapy, chemoradiotherapy followed by adjuvant chemotherapy, and radiotherapy followed by adjuvant chemotherapy. This study is registered with PROSPERO, CRD42016042524. FINDINGS: The network comprised 28 trials and included 8214 patients (6133 [74·7%] were men, 2073 [25·2%] were women, and eight [0·1%] had missing data) enrolled between Jan 1, 1988, and Dec 31, 2016. Median follow-up was 7·6 years (IQR 6·2-13·3). There was no evidence of heterogeneity (p=0·18), and inconsistency was borderline (p=0·10). The three treatments with the highest benefit for overall survival were induction chemotherapy with taxanes followed by chemoradiotherapy (hazard ratio 0·75; 95% CI 0·59-0·96; p score 92%), induction chemotherapy without taxanes followed by chemoradiotherapy (0·81; 0·69-0·95; p score 87%), and chemoradiotherapy followed by adjuvant chemotherapy (0·88; 0·75-1·04; p score 72%), compared with concomitant chemoradiotherapy (p score 46%). INTERPRETATION: The inclusion of new trials modified the conclusion of the previous network meta-analysis. In this updated network meta-analysis, the addition of either induction chemotherapy or adjuvant chemotherapy to chemoradiotherapy improved overall survival over chemoradiotherapy alone in nasopharyngeal carcinoma. FUNDING: Institut National du Cancer and Ligue Nationale Contre le Cancer.

Predictability of inter-regional cerebral perfusion similarity on dopamine responsiveness and the moderation role of cognition in PD patients.

BACKGROUND: Large heterogeneity can be found in dopamine responsiveness of patients with Parkinson's disease (PD). Instantly and objectively understanding dopamine responsiveness of patients may help clinical practice. PURPOSE: This PD study explored the predictability of off-state inter-regional cerebral blood flow (CBF) perfusion similarity on patient's dopamine responsiveness and tested whether the predictive power could be moderated by patient's cognitive status. MATERIALS AND METHOD: The PD cohort with 192 patients (containing off state and on state (PD-off and PD-on)) and the normal control (NC) cohort with 92 subjects were included. The intra-individual CBF relative variation networks were constructed and compared between PD-off and PD-on, PD-off and NC to identify the alterations caused by dopamine depletion. Based on that, regression analysis of off-state inter-regional CBF perfusion similarity on patient's dopamine responsiveness was performed. Finally, moderation analysis was conducted to test the moderation role of cognition on the regression model. RESULTS: In the PD-off cohort, a total of 82 edges in the network were identified that affected by dopamine depletion. Off-state inter-regional CBF perfusion similarity was found that had a significant influence on patient's dopamine responsiveness. Cognitive status was validated that positively moderated the relationship between off-state inter-regional CBF perfusion similarity and dopamine responsiveness. CONCLUSION: Dopamine responsiveness of PD patient could be predicted by off-state inter-regional CBF perfusion similarity. Patient's cognitive status might have a positive moderation effect on his/her dopamine responsiveness.

Assessment of vibration modulated regional cerebral blood flow with MRI.

Human brain experiences vibration of certain magnitude and frequency during various physical activities such as vehicle transportation and machine operation, which may cause traumatic brain injury or other brain diseases. However, the mechanisms of brain pathogenesis due to vibration are not fully elucidated due to the lack of techniques to study brain functions while applying vibration to the brain at a specific magnitude and frequency. Here, this study reported a custom-built head-worn electromagnetic actuator that applied vibration to the brain in vivo at an accurate frequency inside a magnetic resonance imaging scanner while cerebral blood flow (CBF) was acquired. Using this technique, CBF values from 45 healthy volunteers were quantitatively measured immediately following vibration at 20, 30, 40 Hz, respectively. Results showed increasingly reduced CBF with increasing frequency at multiple regions of the brain, while the size of the regions expanded. Importantly, the vibration-induced CBF reduction regions largely fell inside the brain's default mode network (DMN), with about 58 or 46% overlap at 30 or 40 Hz, respectively. These findings demonstrate that vibration as a mechanical stimulus can change strain conditions, which may induce CBF reduction in the brain with regional differences in a frequency-dependent manner. Furthermore, the overlap between vibration-induced CBF reduction regions and DMN suggested a potential relationship between external mechanical stimuli and cognitive functions.

Gray matter structural covariance networks patterns associated with autopsy-confirmed LATE-NC compared to Alzheimer's disease pathology.

BACKGROUND: Cases with the limbic-predominant age-related TAR DNA-binding protein 43 (TDP-43) encephalopathy neuropathologic change (LATE-NC), Alzheimer's disease (AD), and mixed AD+TDP-43 pathology (AD+LATE-NC) share similar symptoms, which makes it a challenge for accurate diagnosis. Exploring the patterns of gray matter structural covariance networks (SCNs) in these three types may help to clarify the underlying mechanism and provide a basis for clinical interventions. METHODS: We included ante-mortem MRI data of 10 LATE-NC, 39  AD, and 25  AD+LATE-NC from the ADNI autopsy sample. We used four regions of interest (left posterior cingulate cortex, right entorhinal cortex, frontoinsular and dorsolateral prefrontal cortex) to anchor the default mode network (DMN), salience network (SN), and executive control network (ECN). Finally, we assessed the SCN alternations using a multi-regression model-based linear-interaction analysis. RESULTS: Cases with autopsy-confirmed LATE-NC and AD showed increased structural associations involving DMN, ECN, and SN. Cases with AD+LATE-NC showed increased structural association within DMN while decreased structural association between DMN and ECN. The volume of peak clusters showed significant associations with cognition and AD pathology. CONCLUSIONS: This study showed different SCN patterns in the cases with LATE-NC, AD, and AD+LATE-NC, and indicated the network disconnection mechanism underlying these three neuropathological progressions. Further, SCN may serve as an effective biomarker to distinguish between different types of dementia.

Functional connectome predicting individual gait function and its relationship with molecular architecture in Parkinson's disease.

Gait impairment is a common symptom of Parkinson's disease (PD), but its neural signature remains unclear due to the interindividual variability of gait performance. Identifying a robust gait-brain correlation at the individual level would provide insight into a generalizable neural basis of gait impairment. In this context, this study aimed to detect connectome that can predict individual gait function of PD, and follow-up analyses assess the molecular architecture underlying the connectome by relating it to the neurotransmitter-receptor/transporter density maps. Resting-state functional magnetic resonance imaging was used to detect the functional connectome, and gait function was assessed via a 10 m-walking test. The functional connectome was first detected within drug-naive patients (N = 48) by using connectome-based predictive modeling following cross-validation and then successfully validated within drug-managed patients (N = 30). The results showed that the motor, subcortical, and visual networks played an important role in predicting gait function. The connectome generated from patients failed to predict the gait function of 33 normal controls (NCs) and had distinct connection patterns compared to NCs. The negative connections (connection negatively correlated with 10 m-walking-time) pattern of the PD connectome was associated with the density of the D2 receptor and VAChT transporter. These findings suggested that gait-associated functional alteration induced by PD pathology differed from that induced by aging degeneration. The brain dysfunction related to gait impairment was more commonly found in regions expressing more dopaminergic and cholinergic neurotransmitters, which may aid in developing targeted treatments.

Normalization effect of dopamine replacement therapy on brain functional connectome in Parkinson's disease.

Dopamine replacement therapy (DRT) represents the standard treatment for Parkinson's disease (PD), however, instant and long-term medication influence on patients' brain function have not been delineated. Here, a total of 97 drug-naïve patients, 43 patients under long-term DRT, and 94 normal control (NC) were, retrospectively, enrolled. Resting-state functional magnetic resonance imaging data and motor symptom assessments were conducted before and after levodopa challenge test. Whole-brain functional connectivity (FC) matrices were constructed. Network-based statistics were performed to assess FC difference between drug-naïve patients and NC, and these significant FCs were defined as disease-related connectomes, which were used for further statistical analyses. Patients showed better motor performances after both long-term DRT and levodopa challenge test. Two disease-related connectomes were observed with distinct patterns. The FC of the increased connectome, which mainly consisted of the motor, visual, subcortical, and cerebellum networks, was higher in drug-naïve patients than that in NC and was normalized after long-term DRT (p-value <.050). The decreased connectome was mainly composed of the motor, medial frontal, and salience networks and showed significantly lower FC in all patients than NC (p-value <.050). The global FC of both increased and decreased connectome was significantly enhanced after levodopa challenge test (q-value <0.050, false discovery rate-corrected). The global FC of increased connectome in ON-state was negatively associated with levodopa equivalency dose (r = -.496, q-value = 0.007). Higher global FC of the decreased connectome was related to better motor performances (r = -.310, q-value = 0.022). Our findings provided insights into brain functional alterations under dopaminergic medication and its benefit on motor symptoms.

Neuropsychiatric symptoms associated multimodal brain networks in Alzheimer's disease.

Concomitant neuropsychiatric symptoms (NPS) are associated with accelerated Alzheimer's disease (AD) progression. Identifying multimodal brain imaging patterns associated with NPS may help understand pathophysiology correlates AD. Based on the AD continuum, a supervised learning strategy was used to guide four-way multimodal neuroimaging fusion (Amyloid, Tau, gray matter volume, brain function) by using NPS total score as the reference. Loadings of the identified multimodal patterns were compared across the AD continuum. Then, regression analyses were performed to investigate its predictability of longitudinal cognition performance. Furthermore, the fusion analysis was repeated in the four NPS subsyndromes. Here, an NPS-associated pathological-structural-functional covaried pattern was observed in the frontal-subcortical limbic circuit, occipital, and sensor-motor region. Loading of this multimodal pattern showed a progressive increase with the development of AD. The pattern significantly correlates with multiple cognitive domains and could also predict longitudinal cognitive decline. Notably, repeated fusion analysis using subsyndromes as references identified similar patterns with some unique variations associated with different syndromes. Conclusively, NPS was associated with a multimodal imaging pattern involving complex neuropathologies, which could effectively predict longitudinal cognitive decline. These results highlight the possible neural substrate of NPS in AD, which may provide guidance for clinical management.

An artificial-intelligence-based age-specific template construction framework for brain structural analysis using magnetic resonance images.

It is an essential task to construct brain templates and analyze their anatomical structures in neurological and cognitive science. Generally, templates constructed from magnetic resonance imaging (MRI) of a group of subjects can provide a standard reference space for analyzing the structural and functional characteristics of the group. With recent development of artificial intelligence (AI) techniques, it is desirable to explore AI registration methods for quantifying age-specific brain variations and tendencies across different ages. In this article, we present an AI-based age-specific template construction (called ASTC) framework for longitudinal structural brain analysis using T1-weighted MRIs of 646 subjects from 18 to 82 years old collected from four medical centers. Altogether, 13 longitudinal templates were constructed at a 5-year age interval using ASTC, and tissue segmentation and substructure parcellation were performed for analysis across different age groups. The results indicated consistent changes in brain structures along with aging and demonstrated the capability of ASTC for longitudinal neuroimaging study.

Current coffee consumption is associated with decreased striatal dopamine transporter availability in Parkinson's disease patients and healthy controls.

BACKGROUND: Coffee is the most widely consumed psychostimulant worldwide. Emerging evidence indicates that coffee consumption habit significantly reduces the risk of developing Parkinson's disease (PD). However, the effect of coffee consumption on nigrostriatal dopaminergic neurodegeneration is still largely unknown. We therefore aim to investigate the role of coffee consumption in nigrostriatal dopaminergic neurodegeneration using dopamine transporter (DAT) imaging in PD and healthy controls (HC). METHODS: A total of 138 PD patients and 75 HC with questionnaires about coffee consumption, and DAT scans were recruited from the Parkinson's Progression Markers Initiative cohort. Demographic, clinical, and striatal DAT characteristics were compared across subgroups of current, former, and never coffee consumers in PD and HC, respectively. Furthermore, partial correlation analyses were performed to determine whether there was a relationship between coffee cups consumed per day and striatal DAT characteristics in each striatal region. In addition, the factors that may have influenced the loss of nigrostriatal dopaminergic neurons were included in multiple linear regression analyses to identify significant contributing factors to DAT availability in each striatal region. RESULTS: PD patients had lower DAT availability in each striatal region than HC (p < 0.001). In PD patients, there were significant differences in DAT availability in the caudate (p = 0.008, Bonferroni corrected) across three PD subgroups. Specifically, post hoc tests showed that current coffee consumers had significantly lower DAT availability in the caudate than former coffee consumers (p = 0.01) and never coffee consumers (p = 0.022). In HC, there were significant differences in DAT availability in the caudate (p = 0.031, Bonferroni uncorrected) across three HC subgroups. Specifically, post hoc tests showed that current coffee consumers had significantly lower DAT availability in the caudate than former coffee consumers (p = 0.022). Moreover, correlation analysis revealed that cups per day were negatively correlated with DAT availability in the caudate in current consumers of PD patients (r = - 0.219, p = 0.047). In addition, multiple linear regression analyses showed that current coffee consumption remained an independent predictor of decreased DAT availability in the caudate in PD patients and HC. CONCLUSIONS: This study demonstrates that current coffee consumption is associated with decreased striatal DAT availability in the caudate. However, the effects of caffeine on striatal DAT may fade and disappear after quitting coffee consumption. TRIAL REGISTRATION: ClinicalTrials.gov, NCT01141023.

Increased iron deposition in nucleus accumbens associated with disease progression and chronicity in migraine.

BACKGROUND: Migraine is one of the world's most prevalent and disabling diseases. Despite huge advances in neuroimaging research, more valuable neuroimaging markers are still urgently needed to provide important insights into the brain mechanisms that underlie migraine symptoms. We therefore aim to investigate the regional iron deposition in subcortical nuclei of migraineurs as compared to controls and its association with migraine-related pathophysiological assessments. METHODS: A total of 200 migraineurs (56 chronic migraine [CM], 144 episodic migraine [EM]) and 41 matched controls were recruited. All subjects underwent MRI and clinical variables including frequency/duration of migraine, intensity of migraine, 6-item Headache Impact Test (HIT-6), Migraine Disability Assessment (MIDAS), and Pittsburgh Sleep Quality Index (PSQI) were recorded. Quantitative susceptibility mapping was employed to quantify the regional iron content in subcortical regions. Associations between clinical variables and regional iron deposition were studied as well. RESULTS: Increased iron deposition in the putamen, caudate, and nucleus accumbens (NAC) was observed in migraineurs more than controls. Meanwhile, patients with CM had a significantly higher volume of iron deposits compared to EM in multiple subcortical nuclei, especially in NAC. Volume of iron in NAC can be used to distinguish patients with CM from EM with a sensitivity of 85.45% and specificity of 71.53%. As the most valuable neuroimaging markers in all of the subcortical nuclei, higher iron deposition in NAC was significantly associated with disease progression, and higher HIT-6, MIDAS, and PSQI. CONCLUSIONS: These findings provide evidence that iron deposition in NAC may be a biomarker for migraine chronicity and migraine-related dysfunctions, thus may help to understand the underlying vascular and neural mechanisms of migraine. TRIAL REGISTRATION: ClinicalTrials.gov, number NCT04939922.