Amplitude Of Low-frequency Fluctuation Research Articles

Analysis of the Kidney-Brain Axis via the Fractional Amplitude of Low-Frequency Fluctuation in Patients with Diabetic Nephropathy

Analysis of the Kidney-Brain Axis via the Fractional Amplitude of Low-Frequency Fluctuation in Patients with Diabetic Nephropathy

Magnetic resonance imaging studies on acupuncture therapy in cerebral ischemic stroke: A systematic review

Research has started using Magnetic Resonance Imaging (MRI) to elucidate the action of acupuncture on neuroplasticity following ischemic stroke (IS). Acupuncture is thought to be a potentially beneficial treatment for IS. However, the results remain inconsistent because of MRI processing techniques and study design variations. Therefore, this coordinate-based meta-analysis and systematic review aimed to assess the current state of knowledge about the regional brain fMRI imaging characteristics in acupuncture-treated IS patients. Twenty studies—including 392 IS patients and 256 health controls—met the inclusion criteria after searches via Chinese and English databases. The design techniques utilized in this research were mainly owned before-and-after controlled and randomized controlled trials. Only one study used independent component analysis (ICA), while the majority of MRI analytical techniques focus on functional connectivity (FC) and fractional amplitude of low-frequency fluctuation (fALFF/ALFF). The findings demonstrated a significant rise in the ALFF value of the left supplementary motor region after treatment with acupuncture. The left cerebellum, right inferior frontal gyrus, and hemisphere lobule VIII all showed substantial activation of Reho values. The triangular portion, BA 48, the left inferior network and inferior longitudinal fasciculus, as well as other brain areas decreased in the left inferior frontal gyrus; most research has used FC analysis employing motor areas as seed regions. We found that acupuncture regulated the motor-related network and reorganized the language-related network. Furthermore, acupuncture appears therapeutic for several IS effects, which may be connected to how acupuncture regulates the brain's plasticity.

Brain Functional Alterations in Patients With Benign Paroxysmal Positional Vertigo Demonstrate the Visual-Vestibular Interaction and Integration.

This study aimed to analyze the features of resting-state functional magnetic resonance imaging (rs-fMRI) and clinical relevance in patients with benign paroxysmal positional vertigo (BPPV) that have undergone repositioning maneuvers. A total of 38 patients with BPPV who have received repositioning maneuvers and 38 matched healthy controls (HCs) were enrolled in the present study from March 2018 to August 2021. Imaging analysis software was employed for functional image preprocessing and indicator calculation, mainly including the amplitude of low-frequency fluctuation (ALFF), fractional ALFF (fALFF), percent amplitude of fluctuation (PerAF), and seed-based functional connectivity (FC). Statistical analysis of the various functional indicators in patients with BPPV and HCs was also conducted, and correlation analysis with clinical data was performed. Patients with BPPV displayed decrease in ALFF, fALFF, and PerAF values, mainly in the bilateral occipital lobes in comparison with HCs. Additionally, their ALFF and fALFF values in the proximal vermis region of the cerebellum increased relative to HCs. The PerAF values in the bilateral paracentral lobules, the right supplementary motor area (SMA), and the left precuneus decreased in patients with BPPV and were negatively correlated with dizziness visual analog scale (VAS) scores 1 week after repositioning (W1). In addition, in the left fusiform gyrus and lingual gyrus, the PerAF values show a negative correlation with dizziness handicap inventory (DHI) scores at initial visit (W0). Seed-based FC analysis using the seeds from differential clusters of fALFF, ALFF, and PerAF showed reductions between the left precuneus and bilateral occipital lobe, the left precuneus and left paracentral lobule, and within the occipital lobes among patients with BPPV. The spontaneous activity of certain brain regions in the bilateral occipital and frontoparietal lobes of patients with BPPV was reduced, whereas the activity in the cerebellar vermis was increased. Additionally, there were reductions in FC between the precuneus and occipital cortex or paracentral lobule, as well as within the occipital cortex. The functional alterations in these brain regions may be associated with the inhibitory interaction and functional integration of visual, vestibular, and sensorimotor systems. The functional alterations observed in the visual cortex and precuneus may represent adaptive responses associated with residual dizziness.

Effects of repetitive transcranial magnetic stimulation at different targets on brain function in stroke patients: a randomized controlled trial.

Repetitive transcranial magnetic stimulation (rTMS) can improve post stroke motor function. However, there is little research on targets. The purpose of this study is to investigate the effects of rTMS therapy with different targets on post stroke motor function and neural plasticity. Fifty-four subjects were randomly divided into M1 (Primary motor area) group, SMA (supplementary motor area) group and Sham group, and were given 10 Hz on the affected M1 area, SMA area and sham stimulation rTMS. The primary outcomes included Fugl-Meyer Assessment Upper Extremity Scale (FMA-UE), Fugl-Meyer Assessment Lower Extremity Scale (FMA-LE) and Berg balance scale (BBS). Secondary outcomes: amplitude of low frequency fluctuation (ALFF), regional homogeneity (ReHo) and functional connectivity (FC) were analyzed by functional magnetic resonance imaging (fMRI) to evaluate brain functional activation and functional connectivity changes. The 2-way repeated-measures ANOVA revealed a significant group × time interaction (F = 23.494, p < 0.001; F = 10.801, p < 0.001; F = 17.812, p < 0.001) in the FMA-UE, FMA-LE and BBS scores. Post hoc analysis indicated that 4 weeks of SMA rTMS resulted in an increase in FMA-UE, FMA-LE and BBS scores compared with Sham group (p = 0.006; p = 0.033; p = 0.012), SMA group was significantly increased in BBS compared with M1 group (p = 0.034). Moreover, there were significant effects of time in all 3 groups in the FMA-UE, FMA-LE and BBS scores (p < 0.001). In addition, the increase of ALFF in the supramarginal gyrus on the affected side was correlated with better FMA-UE recovery, the increase of ALFF in the middle temporal gyrus and the middle frontal gyrus on the affected side was positively correlated with the improvement of BBS, and the ALFF in the cerebellum on the healthy side was negatively correlated with the improvement of BBS. There was a positive correlation between FC (SMA - ipsilateral cerebellum) changes and BBS changes in SMA group. In conclusion, SMA-rTMS intervention has a better recovery effect on motor dysfunction after stroke than Sham-rTMS. SMA-rTMS led to similar improvement on motor function but significantly greater improvement on balance compared to M1-rTMS, and this may pave a new way for stroke rehabilitation. Registration number: ChiCTR2200060955, https://www.chictr.org.cn/.

Altered brain function in treatment-resistant depression patients: A resting-state functional magnetic resonance imaging study

BackgroundIt has been established that there are functional changes in the brain of treatment-resistant depression (TRD) patients, but previous studies of functional connectivity (FC) usually involved selection of regions of interest based on accumulated a priori knowledge of the disorder. In this study, we combine amplitude of low-frequency fluctuation (ALFF) and FC; this approach, based on the abnormal ALFF, may provide some insights into the neural basis of the disease in terms of fMRI signals of low-frequency fluctuations. MethodsA total of 16 TRD patients, who visited the Qingdao Mental Health Center, Shandong Province, China between March 2023 and January 2024, along with 16 normal subjects, were enrolled into this study for functional imaging. In this study, we first explored the ALFF changes of TRD patients at a baseline resting state. Second, we selected the regions that were significantly changed in the ALFF as seeds and calculated the regional activity and functional connectivity (FC) of these regions using a seed-based approach. We also calculated correlations between the percent change in the PDQ-5D scores and ALFF values in brain regions with differing activity for TRD patients. ResultsDuring the baseline resting state, by using the ALFF, we found a significantly decreased or increased ALFF in the TRD patients relative to the controls. These regions were located in the left/right postcentral gyrus (PoCG.L/PoCG.R), right cuneus(CUN.R). We found that the ALFF values of the right hippocampus (HIP.R) in the TRD group were negatively correlated with the PDQ-5D score. Then, we selected these brain regions as seeds to investigate the FC changes in brains of TRD patients. We found abnormal functional connectivity in left/right middle frontal gyrus(MFG.L/MFG.R), the right Inferior frontal gyrus, opercular part (IFGoperc.R), the left/right Anterior cingulate and paracingulate gyri (ACC.L/ACC.R), the right supramarginal gyrus (SMG.R), and the right Calcarine fissure and surrounding cortex (CAL.R). ConclusionWe found a larger range of altered brain regions in TRD patients compared to healthy controls, especially in the central executive network (CEN), salience network (SN) and default mode network (DMN).

Functional activity, functional connectivity and complex network biomarkers of progressive hyposmia Parkinson's disease with no cognitive impairment: evidences from resting-state fMRI study.

Olfactory dysfunction stands as one of the most prevalent non-motor symptoms in the initial stage of Parkinson's disease (PD). Nevertheless, the intricate mechanisms underlying olfactory deficits in Parkinson's disease still remain elusive. This study collected rs-fMRI data from 30 PD patients [15 with severe hyposmia (PD-SH) and 15 with no/mild hyposmia (PD-N/MH)] and 15 healthy controls (HC). To investigate functional segregation, the amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo) were utilized. Functional connectivity (FC) analysis was performed to explore the functional integration across diverse brain regions. Additionally, the graph theory-based network analysis was employed to assess functional networks in PD patients. Furthermore, Pearson correlation analysis was conducted to delve deeper into the relationship between the severity of olfactory dysfunction and various functional metrics. We discovered pronounced variations in ALFF, ReHo, FC, and topological brain network attributes across the three groups, with several of these disparities exhibiting a correlation with olfactory scores. Using fMRI, our study analyzed brain function in PD-SH, PD-N/MH, and HC groups, revealing impaired segregation and integration in PD-SH and PD-N/MH. We hypothesize that changes in temporal, frontal, occipital, and cerebellar activities, along with aberrant cerebellum-insula connectivity and node degree and betweenness disparities, may be linked to olfactory dysfunction in PD patients.

Abnormal brain regional activity in acute thyrotoxic myopathy assessed by resting-state functional MRI.

The neurophysiological mechanisms underlying manifestations of bulbar paralysis in acute thyrotoxic myopathy (ATM) and the afflicted brain areas are unclear. We used resting-state functional magnetic resonance imaging (rs-fMRI) to evaluate the regional brain activities in patients with ATM. In total, 16 patients with ATM, 16 patients with hyperthyroidism without ATM, and 16 healthy controls underwent functional MRI scans. By calculating the fractional amplitude of low-frequency fluctuation (fALFF), regional homogeneity (ReHo), and functional connectivity (FC), we assessed variations in resting-state cerebral activity. The correlation between the resting-state functional indexes and clinical assessments was also explored. Compared to the hyperthyroid patients, patients with ATM had stronger ReHo in the left precentral gyrus, reduced ReHo in the left orbitofrontal gyrus (OFG), and decreased FC in the left precentral gyri, left superior frontal gyrus (SFG), and left middle frontal gyrus (MFG). Patients with ATM showed reduced fALFF and ReHo in the right SFG and decreased ReHo in the bilateral supplementary motor area (SMA). A significantly decreased FC in the left SFG and left MFG, right precentral gyrus, and the orbital part of the right interior frontal gyrus was observed in patients with ATM compared to healthy controls. Additionally, fALFF and ReHo values were positively correlated with serum thyroid-related hormones and antibodies. The findings of rs-fMRI demonstrate that particular brain regions' functional activity was aberrant in individuals with ATM, especially in SFG area. This finding may help with better understanding of underlying pathophysiology of patients with ATM.

Altered static brain activity and functional connectivity after heat stroke.

This study aimed to investigate the alteration of brain function based on resting-state functional MRI in patients after heat stroke. This study included 10 cases of patients after heat stroke and 10 cases of healthy controls. Abnormal brain function was calculated using amplitude of low-frequency fluctuations (ALFF) and degree centrality analysis, as well as functional connectivity analysis based on regions of interest (ROI). Correlation analyses were performed to evaluate the association between brain function changes and clinical scales. Combining ALFF and degree centrality results, the decreased brain regions included the left cuneus and the right angular gyrus, while the increased brain regions included the right cerebellar_Crus1. Using the left cuneus with significant differences in ALFF and degree centrality as ROI, the functional connectivity results revealed decreased brain regions including bilateral lingual gyrus, bilateral postcentral cingulate gyrus, and left precentral gyrus. The degree centrality value of the right cerebellar_Crus1 was positively correlated with glasgow coma scale (GCS) scores ( r = 0.726, P = 0.027), and the functional connectivity value of the right posterior cingulate gyrus was positively correlated with GCS scores ( r = 0.717, P = 0.030). Heat stroke patients exhibit abnormal activity in multiple brain regions, which has important clinical significance for evaluating the severity of the disease.

PD-ARnet: a deep learning approach for Parkinson’s disease diagnosis from resting-state fMRI

Objective. The clinical diagnosis of Parkinson's disease (PD) relying on medical history, clinical symptoms, and signs is subjective and lacks sensitivity. Resting-state fMRI (rs-fMRI) has been demonstrated to be an effective biomarker for diagnosing PD.Approach.This study proposes a deep learning approach for the automatic diagnosis of PD using rs-fMRI, named PD-ARnet. Specifically, PD-ARnet utilizes Amplitude of Low Frequency Fluctuations and Regional Homogeneity extracted from rs-fMRI as inputs. The inputs are then processed through a developed dual-branch 3D feature extractor to perform advanced feature extraction. During this process, a Correlation-Driven weighting module is applied to capture complementary information from both features. Subsequently, the Attention-Enhanced fusion module is developed to effectively merge two types of features, and the fused features are input into a fully connected layer for automatic diagnosis classification.Main results.Using 145 samples from the PPMI dataset to evaluate the detection performance of PD-ARnet, the results indicated an average classification accuracy of 91.6% (95% confidence interval [CI]: 90.9%, 92.4%), precision of 94.7% (95% CI: 94.2%, 95.1%), recall of 86.2% (95% CI: 84.9%, 87.4%), F1 score of 90.2% (95% CI: 89.3%, 91.1%), and AUC of 92.8% (95% CI: 91.1%, 95.0%).Significance.The proposed method has the potential to become a clinical auxiliary diagnostic tool for PD, reducing subjectivity in the diagnostic process, and enhancing diagnostic efficiency and consistency.

Altered spontaneous brain activity patterns in hypertensive retinopathy using fractional amplitude of low-frequency fluctuations: a functional magnetic resonance imaging study.

To study functional brain abnormalities in patients with hypertensive retinopathy (HR) and to discuss the pathophysiological mechanisms of HR by fractional amplitude of low-frequency fluctuations (fALFFs) method. Twenty HR patients and 20 healthy controls (HCs) were respectively recruited. The age, gender, and educational background characteristics of the two groups were similar. After functional magnetic resonance imaging (fMRI) scanning, the subjects' spontaneous brain activity was evaluated with the fALFF method. Receiver operating characteristic (ROC) curve analysis was used to classify the data. Further, we used Pearson's correlation analysis to explore the relationship between fALFF values in specific brain regions and clinical behaviors in patients with HR. The brain areas of the HR group with lower fALFF values than HCs were the right orbital part of the middle frontal gyrus (RO-MFG) and right lingual gyrus. In contrast, the values of fALFFs in the left middle temporal gyrus (MTG), left superior temporal pole (STP), left middle frontal gyrus (MFG), left superior marginal gyrus (SMG), left superior parietal lobule (SPL), and right supplementary motor area (SMA) were higher in the HR group. The results of a t-test showed that the average values of fALFFs were statistically significantly different in the HR group and HC group (P<0.001). The fALFF values of the left middle frontal gyrus in HR patients were positively correlated with anxiety scores (r=0.9232; P<0.0001) and depression scores (r=0.9682; P<0.0001). fALFF values in multiple brain regions of HR patients are abnormal, suggesting that these brain regions in HR patients may be dysfunctional, which may help to reveal the pathophysiological mechanisms of HR.

Disruptive and complementary effects of depression symptoms on spontaneous brain activity in the subcortical vascular mild cognitive impairment.

Although depression symptoms are commonly reported in patients with subcortical vascular mild cognitive impairment (svMCI), their impact on brain functions remains largely unknown, with diagnoses mainly dependent on behavioral assessments. In this study, we analyzed resting-state fMRI data from a cohort of 34 svMCI patients, comprising 18 patients with depression symptoms (svMCI+D) and 16 patients without (svMCI-D), along with 34 normal controls (NC). The study used the fraction of the amplitude of low-frequency fluctuations (fALFF), resting-state functional connectivity, correlation analyses, and support vector machine (SVM) techniques. The fALFF of the right cerebellum (CERE.R) differed among the svMCI+D, svMCI-D, and NC groups. Specifically, the regional mean fALFF of CERE. R was lower in svMCI-D patients compared to NC but higher in svMCI+D patients compared to svMCI-D patients. Moreover, the adjusted fALFF of CERE. R showed a significant correlation with Montreal Cognitive Assessment (MOCA) scores in svMCI-D patients. The fALFF of the right orbital part of the superior frontal gyrus was significantly correlated with Hamilton Depression Scale scores in svMCI+D patients, whereas the fALFF of the right postcingulate cortex (PCC.R) showed a significant correlation with MOCA scores in svMCI-D patients. Furthermore, RSFC between PCC. R and right precuneus, as well as between CERE. R and the right lingual gyrus (LING.R), was significantly reduced in svMCI-D patients compared to NC. In regional analyses, the adjusted RSFC between PCC. R and PreCUN. R, as well as between CERE. R and LING. R, was decreased in svMCI-D patients compared to NC but increased in svMCI+D patients compared to svMCI-D. Further SVM analyses achieved good performances, with an area under the curve (AUC) of 0.82 for classifying svMCI+D, svMCI-D, and NC; 0.96 for classifying svMCI+D and svMCI-D; 0.82 for classifying svMCI+D and NC; and 0.92 for classifying svMCI-D and NC. The study revealed disruptive effects of cognitive impairment, along with both disruptive and complementary effects of depression symptoms on spontaneous brain activity in svMCI. Moreover, these findings suggest that the identified features might serve as potential biomarkers for distinguishing between svMCI+D, svMCI-D, and NC, thereby guiding clinical treatments such as transcranial magnetic stimulation for svMCI.

Spontaneous neural activity underlying neutral and happy speech recognition in noise and its association with psychiatric symptoms in patients with schizophrenia

BackgroundDeficits in speech and emotion perception are intertwined with psychiatric symptoms. How the happy prosody embedded in speech affects target speech-in-noise recognition (TSR) and relates to psychiatric symptoms in patients with schizophrenia (SCHs) remains unclear. This study examined spontaneous brain activity underlying happy TSR and its association with psychiatric symptom dimensions in SCHs. MethodsFifty-four SCHs and 59 healthy control participants (HCs) underwent the TSR task, Positive and Negative Syndrome Scale (PANSS) assessment, and magnetic resonance imaging scanning. Multivariate analyses of partial least squares (PLS) regression were used to explore the associations between whole-brain fractional amplitude of low-frequency fluctuations (fALFF), happy-neutral TSR (target pseudo-sentences were uttered in happy and neutral prosodies), and five PANSS factor scores (excitement/hostility, depression/anxiety, cognition, positive, and negative). ResultsThe happy prosody did not alter TSR or TSR changing rates in either SCHs or HCs. SCHs exhibited lower happy and neutral TSR than HCs. A fALFF PLS component (including precentral/postcentral gyrus, Subcallosal Cortex, several temporal regions, and cerebellum) was associated with happy and neutral TSR. SCHs demonstrated higher PLS fALFF scores and PLS TSR scores than HCs. In SCHs, PLS fALFF scores were correlated with the PANSS positive factor score, and PLS TSR scores were correlated with the PANSS cognition factor score. ConclusionsThe positive-psychiatric-symptoms-related spontaneous activity profile was associated with happy and neutral TSR, contributing to the cognition psychiatric symptoms dimension. The findings suggest the potential to improve positive and cognitive symptoms by enhancing happy and neutral TSR in schizophrenia based on neuroplasticity.

Neural adaptation of the reward system in primary dysmenorrhea.

Introduction: The brain's reward system (RS) reacts differently to pain and its alleviation. This study examined the correlation between RS activity and behavior during both painful and pain-free periods in individuals with primary dysmenorrhea (PDM) to elucidate their varying responses throughout the menstrual cycle. Methods: Ninety-two individuals with PDM and 90 control participants underwent resting-state functional magnetic resonance imaging (rsfMRI) scans during their menstrual and peri-ovulatory phases. Regional homogeneity (ReHo) and amplitude of low-frequency fluctuation (ALFF) analyses were used to evaluate RS responses. Psychological evaluations were conducted using the McGill Pain Questionnaire and the Pain Catastrophizing Scale. Results: ReHo analysis showed higher values in the left putamen and right amygdala of the PDM group during the peri-ovulatory phase compared to the menstrual phase. ALFF analysis revealed lower values in the putamen of the PDM group compared to controls, regardless of phase. ReHo and ALFF values in the putamen, amygdala, and nucleus accumbens were positively correlated with pain scales during menstruation, while ALFF values in the ventral tegmental area inversely correlated with pain intensity. Those with severe PDM (pain intensity ≥7) displayed distinct amygdala ALFF patterns between pain and pain-free phases. PDM participants also had lower ReHo values in the left insula during menstruation, with no direct correlation to pain compared to controls. Discussion: Our study highlights the pivotal role of the RS in dysmenorrhea management, exhibiting varied responses between menstrual discomfort and non-painful periods among individuals with PDM. During menstruation, the RS triggers mechanisms for pain avoidance and cognitive coping strategies, while it transitions to processing rewards during the peri-ovulatory phase. This demonstrates the flexibility of the RS in adapting to the recurring pain experienced by those with PDM.

Impact of high-frequency rTMS combined with pharmacotherapy on the left dorsolateral prefrontal cortex in treating major depressive disorder: A real-world study

BackgroundRepetitive transcranial magnetic stimulation (rTMS) combined with pharmacotherapy is a promising treatment method for depression. However, its treatment mechanism needs further research. MethodsThis study recruited 38 healthy individuals (HC) and 52 patients with severe depression (MDD) and divided patients into two treatment groups: the rTMS combined antidepressant (rTMS+ADP) group and the single antidepressant (ADP) group. We used functional magnetic resonance imaging to calculate the fractional amplitude of low-frequency fluctuations (fALFF) in the left dorsolateral prefrontal cortex (DLPFC) to investigate the functional change after treatment. ResultThe fALFF in the left DLPFC was significantly lower in the MDD group than that in the HC group (p < 0.05). In addition, fALFF values of the left DLPFC negatively correlated with HAMD-24 scores (r = −0.294, p = 0.005). After treatment, both MDD groups showed a significant decrease in HAMD-24 scores, with a response rate of 88.89 % and a remission rate of 62.96 % in the rTMS+ADP group, compared to 64 % response and 56 % remission rates in the ADP group. The fALFF values in patients' left DLPFC significantly reduced in the rTMS+ADP group (p < 0.05), but not in the ADP group. LimitationsOur study only focused on the treatment effect in the left DLPFC, without exploring the other brain regions or networks. ConclusionsThis study emphasizes the significance of the left DLPFC in MDD treatment. However, combined left DLPFC rTMS with ADP causes deviation from the normal resting brain function of the left DLPFC, indicating that future research should explore targeted treatment methods to normalize the left DLPFC.

Convergent Multimodal Imaging Abnormalities in the Dorsal Precuneus in Subjective Cognitive Decline.

A range of imaging modalities have reported Alzheimer's disease-related abnormalities in individuals experiencing subjective cognitive decline (SCD). However, there has been no consistent local abnormality identified across multiple neuroimaging modalities for SCD. We aimed to investigate the convergent local alterations in amyloid-β (Aβ) deposition, glucose metabolism, and resting-state functional MRI (RS-fMRI) metrics in SCD. Fifty SCD patients (66.4±5.7 years old, 19 men [38%]) and 15 normal controls (NC) (66.3±4.4 years old, 5 men [33.3%]) were scanned with both [18F]-florbetapir PET and [18F]-fluorodeoxyglucose PET, as well as simultaneous RS-fMRI from February 2018 to November 2018. Voxel-wise metrics were retrospectively analyzed, including Aβ deposition, glucose metabolism, amplitude of low frequency fluctuation (ALFF), regional homogeneity (ReHo), and degree centrality(DC). The SCD group showed increased Aβ deposition and glucose metabolism (p < 0.05, corrected), as well as decreased ALFF, ReHo, and DC (p < 0.05, uncorrected) in the left dorsal precuneus (dPCu). Furthermore, the dPCu illustrated negative resting-state functional connectivity with the default mode network. Regarding global Aβ deposition positivity, the Aβ deposition in the left dPCu showed a gradient change, i.e., Aβ positive SCD > Aβ negative SCD > Aβ negative NC. Additionally, both Aβ positive SCD and Aβ negative SCD showed increased glucose metabolism and decreased RS-fMRI metrics in the dPCu. The dorsal precuneus, an area implicated in early AD, shows convergent neuroimaging alterations in SCD, and might be more related to other cognitive functions (e.g., unfocused attention) than episodic memory.

Correlation Between the Fractional Amplitude of Low-Frequency Fluctuation and Cognitive Defects in Alzheimer's Disease.

The fractional amplitude of low-frequency fluctuations (fALFFs) can detect spontaneous brain activity. However, the association between abnormal brain activity and cognitive function, amyloid protein (Aβ), and emotion in Alzheimer's disease (AD) patients remains unclear. This study aimed to survey alterations in fALFF in different frequency bands and the relationship between abnormal brain activity, depressive mood, and cognitive function to determine the potential mechanism of AD. We enrolled 34 AD patients and 32 healthy controls (HC). All the participants underwent resting-state magnetic resonance imaging, and slow-4 and slow-5 fALFF values were measured. Subsequently, the study determined the correlation of abnormal brain activity with mood and cognitive function scores. AD patients revealed altered mfALFF values in the slow-5 and slow-4 bands. In the slow-4 band, the altered mfALFF regions were the right cerebellar crus I, right inferior frontal orbital gyrus (IFOG), right supramarginal gyrus, right precuneus, angular gyrus, and left middle cingulate gyrus. Elevated mfALFF values in the right IFOG were negatively associated with Montreal Cognitive Assessment scores, Boston Naming Test, and Aβ1-42 levels. The mfALFF value of the AD group was lower than the HC group in the slow-5 band, primarily within the right inferior parietal lobule and right precuneus. Altered mfALFF values in AD patients are linked with cognitive dysfunction. Compared with HCs, Aβ1-42 levels in AD patients are related to abnormal IFOG activity. Therefore, mfALFF could be a potential biomarker of AD.

Resting-state functional abnormalities in ischemic stroke: a meta-analysis of fMRI studies.

Ischemic stroke is a leading neurological cause of severe disabilities and death in the world and has a major negative impact on patients' quality of life. However, the neural mechanism of spontaneous fluctuating neuronal activity remains unclear. This meta-analysis explored brain activity during resting state in patients with ischemic stroke including 22 studies of regional homogeneity, amplitude of low-frequency fluctuation, and fractional amplitude of low-frequency fluctuation (692 patients with ischemic stroke, 620 healthy controls, age range 35-80years, 41% female, 175 foci). Results showed decreased regional activity in the bilateral caudate and thalamus and increased regional activity in the left superior occipital gyrus and left default mode network (precuneus/posterior cingulate cortex). Meta-analysis of the amplitude of low-frequency fluctuation studies showed that increased activity in the left inferior frontal gyrus was reduced across the progression from acute to chronic phases. These findings may indicate that disruption of the subcortical areas and default mode network could be one of the core functional abnormalities in ischemic stroke. Altered brain activity in the inferior frontal gyrus could be the imaging indicator of brain recovery/plasticity after stroke damage, which offers potential insight into developing prediction models and therapeutic strategies for ischemic stroke rehabilitation and recovery.

Molecular mechanisms and behavioral relevance underlying neural correlates of childhood neglect

BackgroundChildhood neglect is associated with brain changes, yet the molecular mechanisms and behavioral relevance underlying such associations remain elusive. MethodsWe calculated fractional amplitude of low-frequency fluctuations (fALFF) using resting-state functional MRI and tested their correlation with childhood neglect across a large sample of 510 healthy young adults. Then, we investigated the spatial relationships of the identified neural correlates of childhood neglect with gene expression, neurotransmitter, and behavioral domain atlases. ResultsWe found that more severe childhood neglect was correlated with higher fALFF in the bilateral anterior cingulate cortex. Remarkably, the identified neural correlates of childhood neglect were spatially correlated with expression of gene categories primarily involving neuron, synapse, ion channel, cognitive and perceptual processes, and physiological response and regulation. Concurrently, there were significant associations between the neural correlates and specific neurotransmitter systems including serotonin and GABA. Finally, neural correlates of childhood neglect were associated with diverse behavioral domains implicating mental disorders, emotion, cognition, and sensory perception. LimitationsThe cross-sectional study design cannot unequivocally establish causality. ConclusionsOur findings may not only add to the current knowledge regarding the relationship between childhood neglect and mental health, but also have clinical implications for developing preventive strategies for individuals exposed to childhood neglect who are at risk for mental disorders.

Disturbed Dynamic Brain Activity and Neurovascular Coupling in End-Stage Renal Disease Assessed With MRI.

Pathophysiological mechanisms underlying cognitive impairment in end-stage renal disease (ESRD) remain unclear, with limited studies on the temporal variability of neural activity and its coupling with regional perfusion. To assess neural activity and neurovascular coupling (NVC) in ESRD patients, evaluate the classification performance of these abnormalities, and explore their relationships with cognitive function. Prospective. Exactly 33 ESRD patients and 35 age, sex, and education matched healthy controls (HCs). The 3.0T/3D pseudo-continuous arterial spin labeling, resting-state functional MRI, and 3D-T1 weighted structural imaging. Dynamic (dfALFF) and static (sfALFF) fractional amplitude of low-frequency fluctuations and cerebral blood flow (CBF) were assessed. CBF-fALFF correlation coefficients and CBF/fALFF ratio were determined for ESRD patients and HCs. Their ability to distinguish ESRD patients from HCs was evaluated, alongside assessment of cerebral small vessel disease (CSVD) MRI features. All participants underwent blood biochemical and neuropsychological tests to evaluate cognitive decline. Chi-squared test, two-sample t-test, Mann-Whitney U tests, covariance analysis, partial correlation analysis, family-wise error, false discovery rate, Bonferroni correction, area under the receiver operating characteristic curve (AUC) and multivariate pattern analysis. P < 0.05 denoted statistical significance. ESRD patients exhibited higher dfALFF in triangular part of left inferior frontal gyrus (IFGtriang) and left middle temporal gyrus, lower CBF/dfALFF ratio in multiple brain regions, and decreased CBF/sfALFF ratio in bilateral superior temporal gyrus (STG). Compared with CBF/sfALFF ratio, dfALFF, and sfALFF, CBF/dfALFF ratio (AUC = 0.916) achieved the most powerful classification performance in distinguishing ESRD patients from HCs. In ESRD patients, decreased CBF/fALFF ratio correlated with more severe renal impairment, increased CSVD burden, and cognitive decline (0.4 < |r| < 0.6). ESRD patients exhibited abnormal dynamic brain activity and impaired NVC, with dynamic features demonstrating superior discriminative capacity and CBF/dfALFF ratio showing powerful classification performance. 1 TECHNICAL EFFICACY: Stage 1.

Reward system neurodynamics during menstrual pain modulated by COMT Val158Met polymorphisms.

Primary dysmenorrhea (PDM), characterized by cyclic pain, may involve pain modulation within the reward system (RS). The Catechol-O-methyltransferase (COMT) Val158Met polymorphism, which significantly influences dopamine activity, is linked to the regulation of both acute and chronic pain. This study examines the differential neurodynamic modulation in the RS associated with COMT Val158Met polymorphisms during menstrual pain among PDM subjects. Ninety-one PDM subjects underwent resting-state fMRI during menstruation and were genotyped for COMT Val158Met polymorphisms. The amplitude of low-frequency fluctuation (ALFF) and functional connectivity (FC) analyses were used to assess the RS response. Psychological evaluations included the McGill Pain Questionnaire, Pain Catastrophizing Scale, Beck Anxiety Inventory, and Beck Depression Inventory. Val/Val homozygotes (n = 50) and Met carriers (n = 41) showed no significant differences in McGill Pain Questionnaire, Beck Anxiety Inventory, and Beck Depression Inventory. However, Met carriers exhibited lower scores on the Pain Catastrophizing Scale. Distinct FC patterns was observed between Val/Val homozygotes and Met carriers, specifically between the nucleus accumbens (NAc) and prefrontal cortex, NAc and inferior parietal lobe, ventral tegmental area (VTA) and prefrontal cortex, VTA and precentral gyrus, and VTA and superior parietal lobe. Only Met carriers showed significant correlations between ALFF and FC values of the NAc and VTA with pain-related metrics (McGill Pain Questionnaire and Pain Catastrophizing Scale scores). NAc ALFF and NAc-prefrontal cortex FC values positively correlated with pain-related metrics, while VTA ALFF and VTA-prefrontal cortex and VTA-superior parietal lobe FC values negatively correlated with pain-related metrics. This study reveals that the COMT Val158Met polymorphism results in genotype-specific functional changes in the brain's RS during menstrual pain. In Met carriers, engagement of these regions is potentially linked to motivational reward-seeking and top-down modulation. This polymorphism likely influences the RS's responses, significantly contributing to individual differences in pain regulation.