Most recent paper

Divergent alterations of structural-functional connectivity couplings in first-episode and chronic schizophrenia patients.

Wed, 02/17/2021 - 01:17
Related Articles

Divergent alterations of structural-functional connectivity couplings in first-episode and chronic schizophrenia patients.

Neuroscience. 2021 Feb 12;:

Authors: Kong LY, Huang YY, Lei BY, Ke PF, Li HH, Zhou J, Xiong DS, Li GX, Chen J, Li XB, Xiang ZM, Ning YP, Wu FC, Wu K

Abstract
Emerging evidence suggests that the coupling relating the structural connectivity (SC) of the brain to its functional connectivity (FC) exhibits remarkable changes during development, normal aging, and diseases. Although altered structural-functional connectivity couplings (SC-FC couplings) have been previously reported in schizophrenia patients, the alterations in SC-FC couplings of different illness stages of schizophrenia (SZ) remain largely unknown. In this study, we collected structural and resting-state functional MRI data from 73 normal controls (NCs), 61 first-episode (FeSZ) and 78 chronic (CSZ) schizophrenia patients. Positive and negative syndrome scale (PANSS) scores were assessed for all patients. Structural and functional brain networks were constructed using gray matter volume (GMV) and resting-state magnetic resonance imaging (rs-fMRI) time series measurements. At the connectivity level, the CSZ patients showed significantly increased SC-FC coupling strength compared with the FeSZ patients. At the node strength level, significant decreased SC-FC coupling strength was observed in the FeSZ patients compared to that of the NCs, and the coupling strength was positively correlated with negative PANSS scores. These results demonstrated divergent alterations of SC-FC couplings in FeSZ and CSZ patients. Our findings provide new insight into the neuropathological mechanisms underlying the developmental course of SZ.

PMID: 33588002 [PubMed - as supplied by publisher]

Adaptive Reconfiguration of Intrinsic Community Structure in Children with 5-Year Abacus Training.

Wed, 02/17/2021 - 01:17
Related Articles

Adaptive Reconfiguration of Intrinsic Community Structure in Children with 5-Year Abacus Training.

Cereb Cortex. 2021 Feb 13;:

Authors: Zhang Y, Wang C, Yao Y, Zhou C, Chen F

Abstract
Human learning can be understood as a network phenomenon, underpinned by the adaptive reconfiguration of modular organization. However, the plasticity of community structure (CS) in resting-state network induced by cognitive intervention has never been investigated. Here, we explored the individual difference of intrinsic CS between children with 5-year abacus-based mental calculation (AMC) training (35 subjects) and their peers without prior experience in AMC (31 subjects). Using permutation-based analysis between subjects in the two groups, we found the significant alteration of intrinsic CS, with training-attenuated individual difference. The alteration of CS focused on selective subsets of cortical regions ("core areas"), predominantly affiliated to the visual, somatomotor, and default-mode subsystems. These subsystems exhibited training-promoted cohesion with attenuated interaction between them, from the perspective of individuals' CS. Moreover, the cohesion of visual network could predict training-improved math ability in the AMC group, but not in the control group. Finally, the whole network displayed enhanced segregation in the AMC group, including higher modularity index, more provincial hubs, lower participation coefficient, and fewer between-module links, largely due to the segregation of "core areas." Collectively, our findings suggested that the intrinsic CS could get reconfigured toward more localized processing and segregated architecture after long-term cognitive training.

PMID: 33585902 [PubMed - as supplied by publisher]

Resting-State Cerebello-Cortical Dysfunction in Parkinson's Disease.

Wed, 02/17/2021 - 01:17
Related Articles

Resting-State Cerebello-Cortical Dysfunction in Parkinson's Disease.

Front Neurol. 2020;11:594213

Authors: Palmer WC, Cholerton BA, Zabetian CP, Montine TJ, Grabowski TJ, Rane S

Abstract
Purpose: Recently, the cerebellum's role in Parkinson's disease (PD) has been highlighted. Therefore, this study sought to test the hypothesis that functional connectivity (FC) between cerebellar and cortical nodes of the resting-state networks differentiates PD patients from controls by scanning participants at rest using functional magnetic resonance imaging (fMRI) and investigating connectivity of the cerebellar nodes of the resting-state networks. Materials and Methods: Sixty-two PD participants off medication for at least 12 h and 33 normal controls (NCs) were scanned at rest using blood oxygenation level-dependent fMRI scans. Motor and cognitive functions were assessed with the Movement Disorder Society's Revision of the Unified Parkinson's Disease Rating Scale III and Montreal Cognitive Assessment, respectively. Connectivity was investigated with cerebellar seeds defined by Buckner's 7-network atlas. Results: PD participants had significant differences in FC when compared to NC participants. Most notably, PD patients had higher FC between cerebellar nodes of the somatomotor network (SMN) and the corresponding cortical nodes. Cognitive functioning was differentially associated with connectivity of the cerebellar SMN and dorsal attention network. Further, cerebellar connectivity of frontoparietal and default mode networks correlated with the severity of motor function. Conclusion: Our study demonstrates altered cerebello-cortical FC in PD, as well as an association of this FC with PD-related motor and cognitive disruptions, thus providing additional evidence for the cerebellum's role in PD.

PMID: 33584497 [PubMed]

Functional Connectivity of Nucleus Accumbens and Medial Prefrontal Cortex With Other Brain Regions During Early-Abstinence Is Associated With Alcohol Dependence and Relapse: A Resting-Functional Magnetic Resonance Imaging Study.

Wed, 02/17/2021 - 01:17
Related Articles

Functional Connectivity of Nucleus Accumbens and Medial Prefrontal Cortex With Other Brain Regions During Early-Abstinence Is Associated With Alcohol Dependence and Relapse: A Resting-Functional Magnetic Resonance Imaging Study.

Front Psychiatry. 2021;12:609458

Authors: Yang X, Meng YJ, Tao YJ, Deng RH, Wang HY, Li XJ, Wei W, Hua Y, Wang Q, Deng W, Zhao LS, Ma XH, Li ML, Xu JJ, Li J, Liu YS, Tang Z, Du XD, Coid JW, Greenshaw AJ, Li T, Guo WJ

Abstract
Background: Alcohol dependence (AD) is a chronic recurrent brain disease that causes a heavy disease burden worldwide, partly due to high relapse rates after detoxification. Verified biomarkers are not available for AD and its relapse, although the nucleus accumbens (NAc) and medial prefrontal cortex (mPFC) may play important roles in the mechanism of addiction. This study investigated AD- and relapse-associated functional connectivity (FC) of the NAc and mPFC with other brain regions during early abstinence. Methods: Sixty-eight hospitalized early-abstinence AD male patients and 68 age- and education-matched healthy controls (HCs) underwent resting-functional magnetic resonance imaging (r-fMRI). Using the NAc and mPFC as seeds, we calculated changes in FC between the seeds and other brain regions. Over a follow-up period of 6 months, patients were measured with the Alcohol Use Disorder Identification Test (AUDIT) scale to identify relapse outcomes (AUDIT ≥ 8). Results: Thirty-five (52.24%) of the AD patients relapsed during the follow-up period. AD displayed lower FC of the left fusiform, bilateral temporal superior and right postcentral regions with the NAc and lower FC of the right temporal inferior, bilateral temporal superior, and left cingulate anterior regions with the mPFC compared to controls. Among these FC changes, lower FC between the NAc and left fusiform, lower FC between the mPFC and left cingulate anterior cortex, and smoking status were independently associated with AD. Subjects in relapse exhibited lower FC of the right cingulate anterior cortex with NAc and of the left calcarine sulcus with mPFC compared to non-relapsed subjects; both of these reductions in FC independently predicted relapse. Additionally, FC between the mPFC and right frontal superior gyrus, as well as years of education, independently predicted relapse severity. Conclusion: This study found that values of FC between selected seeds (i.e., the NAc and the mPFC) and some other reward- and/or impulse-control-related brain regions were associated with AD and relapse; these FC values could be potential biomarkers of AD or for prediction of relapse. These findings may help to guide further research on the neurobiology of AD and other addictive disorders.

PMID: 33584384 [PubMed]

Seizure Freedom After Epilepsy Surgery and Higher Baseline Cognition May Be Associated With a Negatively Correlated Epilepsy Network in Temporal Lobe Epilepsy.

Wed, 02/17/2021 - 01:17
Related Articles

Seizure Freedom After Epilepsy Surgery and Higher Baseline Cognition May Be Associated With a Negatively Correlated Epilepsy Network in Temporal Lobe Epilepsy.

Front Neurosci. 2020;14:629667

Authors: Neal EG, Schoenberg MR, Maciver S, Bezchlibnyk YB, Vale FL

Abstract
Background: Brain regions positively correlated with the epileptogenic zone in patients with temporal lobe epilepsy vary in spread across the brain and in the degree of correlation to the temporal lobes, thalamus, and limbic structures, and these parameters have been associated with pre-operative cognitive impairment and seizure freedom after epilepsy surgery, but negatively correlated regions have not been as well studied. We hypothesize that connectivity within a negatively correlated epilepsy network may predict which patients with temporal lobe epilepsy will respond best to surgery. Methods: Scalp EEG and resting state functional MRI (rsfMRI) were collected from 19 patients with temporal lobe epilepsy and used to estimate the irritative zone. Using patients' rsfMRI, the negatively correlated epilepsy network was mapped by determining all the brain voxels that were negatively correlated with the voxels in the epileptogenic zone and the spread and average connectivity within the network was determined. Results: Pre-operatively, connectivity within the negatively correlated network was inversely related to the spread (diffuseness) of that network and positively associated with higher baseline verbal and logical memory. Pre-operative connectivity within the negatively correlated network was also significantly higher in patients who would go on to be seizure free. Conclusion: Patients with higher connectivity within brain regions negatively correlated with the epilepsy network had higher baseline memory function, narrower network spread, and were more likely to be seizure free after surgery.

PMID: 33584184 [PubMed]

Altered intrinsic brain activity in patients with hepatic encephalopathy

Sun, 02/14/2021 - 19:00

J Neurosci Res. 2021 Feb 13. doi: 10.1002/jnr.24788. Online ahead of print.

ABSTRACT

Neuropsychiatric deficits are common in patients with liver cirrhosis (LC), especially in those with hepatic encephalopathy (HE). Previous studies reveal abnormalities in brain activity underlying the neuropsychiatric deficits in LC patients; however, the results are inconsistent. We conducted a meta-analysis of resting-state functional magnetic resonance imaging studies using anisotropic effect-size signed differential mapping software on LC patients to characterize the most consistent regional activity alterations, and to evaluate the potential effect of liver transplantation (LT) on brain function. Meta-regression analyses were performed to explore the relationship between brain alterations and clinical variables. Compared with healthy controls, the typical patterns of increased regional activity in the fronto-striato-cerebellar network and decreased activity in the visuo-sensorimotor network and cingulate gyrus were identified in LC patients, which remained significant in the subgroup meta-analyses of minimal HE (MHE) and overt HE (OHE) patients. Functional deficits in the default mode network (DMN) were found in OHE patients compared with MHE patients. Ammonia level positively correlated with brain activity in the right middle temporal gyrus, and the completion time of number connection test A negatively correlated with brain activity in the left anterior cingulate gyrus. In addition, patients showed increased activity in the visuo-sensorimotor network and precuneus after LT. Our study suggests that alterations in the fronto-striato-cerebellar and visuo-sensorimotor networks may be the potential pathophysiological mechanisms underlying HE, and deficits in the DMN may indicate the progression of HE. LT may improve brain function in the visuo-sensorimotor network. This study has registered in the PROSPERO (CRD42020212758).

PMID:33583085 | DOI:10.1002/jnr.24788

Whole-brain functional MRI registration based on a semi-supervised deep learning model

Sun, 02/14/2021 - 19:00

Med Phys. 2021 Feb 14. doi: 10.1002/mp.14777. Online ahead of print.

ABSTRACT

PURPOSE: Traditional registration of functional magnetic resonance images (fMRI) is typically achieved through registering their co-registered structural MRI. However, it cannot achieve accurate performance in that functional units which are not necessarily located relative to anatomical structures. In addition, registration methods based on functional information focus on gray matter (GM) information but ignore the importance of white matter (WM). To overcome the limitations of exiting techniques, in this paper, we aim to register resting-state fMRI (rs-fMRI) based directly on rs-fMRI data and make full use of GM and WM information to improve the registration performance.

METHODS: We provide a robust representation of WM functional connectivity features using tissue-specific patch-based functional correlation tensors (ts-PFCTs) as auxiliary information to assist registration. Furthermore, we propose a semi-supervised deep learning model that uses GM and WM information (GM ts-PFCTs and WM ts-PFCTs) during training as a fine tweak to improve registration accuracy when such information is not provided in new test image pairs. We implement our method on the 1000 Functional Connectomes Project dataset. To evaluate our method, a group-level analysis was implemented in resting-state brain functional networks after registration, resulting in t maps.

RESULTS: Our method increases the peak t values of the t maps of default mode network, visual network, central executive network, and sensorimotor network to 21.4, 20.0, 18.4, and 19.0, respectively. Through comparison with traditional methods (FMRIB Software Library(FSL), Statistical Parametric Mapping _ Echo Planar Image(SPM_EPI), and SPM_T1), our method achieves an average improvement of 67.39%, 12.96%, and 25.14%.

CONCLUSION: We propose a semi-supervised deep learning network by adding GM and WM information as auxiliary information for resting-state fMRI registration. GM and WM information is extracted and described as GM ts-PFCTs and WM ts-PFCTs. Experimental results show that our method achieves superior registration performance.

PMID:33583029 | DOI:10.1002/mp.14777

Functional connectivity disturbances of ascending reticular activating system and posterior thalamus in juvenile myoclonic epilepsy in relation with photosensitivity: A resting-state fMRI study

Sun, 02/14/2021 - 19:00

Epilepsy Res. 2021 Feb 3;171:106569. doi: 10.1016/j.eplepsyres.2021.106569. Online ahead of print.

ABSTRACT

OBJECTIVE: Juvenile myoclonic epilepsy (JME) is typified by the occurrence of myoclonic seizures after awakening, though another common trait is myoclonic seizures triggered by photic stimulation. We aimed to investigate the functional connectivity (FC) of nuclei in the ascending reticular activating system (ARAS), thalamus and visual cortex in JME with and without photosensitivity.

METHODS: We examined 29 patients with JME (16 photosensitive (PS), 13 non- photosensitive-(NPS)) and 28 healthy controls (HCs) using resting-state functional magnetic resonance imaging (rs-fMRI). Seed-to-voxel FC analyses were performed using 25 seeds, including the thalamus, visual cortex, and ARAS nuclei.

RESULTS: Mesencephalic reticular formation seed revealed significant hyperconnectivity between the bilateral paracingulate gyrus and anterior cingulate cortex in JME group, and in both JME-PS and JME-NPS subgroups compared to HCs (pFWE-corr < 0.001; pFWE-corr < 0.001; pFWE-corr = 0.002, respectively). Locus coeruleus seed displayed significant hyperconnectivity with the bilateral lingual gyri, intracalcarine cortices, occipital poles and left occipital fusiform gyrus in JME-PS group compared to HCs (pFWE-corr <0.001). Additionally, locus coeruleus seed showed significant hyperconnectivity in JME-PS group compared to JME-NPS group with a cluster corresponding to the bilateral lingual gyri and right intracalcarine cortex (pFWE-corr < 0.001). Lastly, the right posterior nuclei of thalamus revealed significant hyperconnectivity with the right superior lateral occipital cortex in JME-PS group compared to HCs (pFWE-corr < 0.002).

CONCLUSIONS: In JME, altered functional connectivity of the arousal networks might contribute to the understanding of myoclonia after awakening, whereas increased connectivity of posterior thalamus might explain photosensitivity.

PMID:33582535 | DOI:10.1016/j.eplepsyres.2021.106569

Higher-order sensorimotor circuit of the brain's global network supports human consciousness

Sun, 02/14/2021 - 19:00

Neuroimage. 2021 Feb 12;231:117850. doi: 10.1016/j.neuroimage.2021.117850. Online ahead of print.

ABSTRACT

Consciousness is a mental characteristic of the human mind, whose exact neural features remain unclear. We aimed to identify the critical nodes within the brain's global functional network that support consciousness. To that end, we collected a large fMRI resting state dataset with subjects in at least one of the following three consciousness states: preserved (including the healthy awake state, and patients with a brain injury history (BI) that is fully conscious), reduced (including the N1-sleep state, and minimally conscious state), and lost (including the N3-sleep state, anesthesia, and unresponsive wakefulness state). We also included a unique dataset of subjects in rapid eye movement sleep state (REM-sleep) to test for the presence of consciousness with minimum movements and sensory input. To identify critical nodes, i.e., hubs, within the brain's global functional network, we used a graph-theoretical measure of degree centrality conjoined with ROI-based functional connectivity. Using these methods, we identified various higher-order sensory and motor regions including the supplementary motor area, bilateral supramarginal gyrus (part of inferior parietal lobule), supragenual/dorsal anterior cingulate cortex, and left middle temporal gyrus, that could be important hubs whose degree centrality was significantly reduced when consciousness was reduced or absent. Additionally, we identified a sensorimotor circuit, in which the functional connectivity among these regions was significantly correlated with levels of consciousness across the different groups, and remained present in the REM-sleep group. Taken together, we demonstrated that regions forming a higher-order sensorimotor integration circuit are involved in supporting consciousness within the brain's global functional network. That offers novel and more mechanism-guided treatment targets for disorders of consciousness.

PMID:33582277 | DOI:10.1016/j.neuroimage.2021.117850

Whole-brain modelling of resting state fMRI differentiates ADHD subtypes and facilitates stratified neuro-stimulation therapy.

Sat, 02/13/2021 - 19:14
Related Articles

Whole-brain modelling of resting state fMRI differentiates ADHD subtypes and facilitates stratified neuro-stimulation therapy.

Neuroimage. 2021 Feb 09;:117844

Authors: Iravani B, Arshamian A, Fransson P, Kaboodvand N

Abstract
Recent advances in non-linear computational and dynamical modelling have opened up the possibility to parametrize dynamic neural mechanisms that drive complex behavior. Importantly, building models of neuronal processes is of key importance to fully understand disorders of the brain as it may provide a quantitative platform that is capable of binding multiple neurophysiological processes to phenotype profiles. In this study, we apply a newly developed adaptive frequency-based model of whole-brain oscillations to resting-state fMRI data acquired from healthy controls and a cohort of attention deficit hyperactivity disorder (ADHD) subjects. As expected, we found that healthy control subjects differed from ADHD in terms of attractor dynamics. However, we also found a marked dichotomy in neural dynamics within the ADHD cohort. Next, we classified the ADHD group according to the level of distance of each individual's empirical network from the two model-based simulated networks. Critically, the model was mirrored in the empirical behavior data with the two ADHD subgroups displaying distinct behavioral phenotypes related to emotional instability (i.e., depression and hypomanic personality traits). Finally, we investigated the applicability and feasibility of our whole-brain model in a therapeutic setting by conducting in silico excitatory stimulations to parsimoniously mimic clinical neuro-stimulation paradigms in ADHD. We tested the effect of stimulating any individual brain region on the key network measures derived from the simulated brain network and its contribution in rectifying the brain dynamics to that of the healthy brain, separately for each ADHD subgroup. This showed that this was indeed possible for both subgroups. However, the current effect sizes were small suggesting that the stimulation protocol needs to be tailored at the individual level. These findings demonstrate the potential of this new modelling framework to unveil hidden neurophysiological profiles and establish tailored clinical interventions.

PMID: 33577937 [PubMed - as supplied by publisher]

Temporal organisation of the brain's intrinsic motor network: the relationship with circadian phenotype and motor performance.

Sat, 02/13/2021 - 19:14
Related Articles

Temporal organisation of the brain's intrinsic motor network: the relationship with circadian phenotype and motor performance.

Neuroimage. 2021 Feb 09;:117840

Authors: Facer-Childs ER, de Campos BM, Middleton B, Skene DJ, Bagshaw AP

Abstract
BACKGROUND: Functional connectivity (FC) of the motor network (MN) is often used to investigate how intrinsic properties of the brain are associated with motor abilities and performance. In addition, the MN is a key feature in clinical work to map the recovery after stroke and aid the understanding of neurodegenerative disorders. Time of day variation and individual differences in circadian timing, however, have not yet been considered collectively when looking at FC.
METHODS: A total of 33 healthy, right handed individuals (13 male, 23.1 ± 4.2 years) took part in the study. Actigraphy, sleep diaries and circadian phase markers (dim light melatonin onset and cortisol awakening response) were used to determine early (ECP, n =13) and late (LCP, n = 20) circadian phenotype groups. Resting state functional MRI testing sessions were conducted at 14:00 h, 20:00 h and 08:00 h and preceded by a maximum voluntary contraction test for isometric grip strength to measure motor performance.
RESULTS: Significant differences in FC of the MN between ECPs and LCPs were found, as well as significant variations between different times of day. A higher amplitude in diurnal variation of FC and performance was observed in LCPs compared to ECPs, with the morning being most significantly affected. Overall, lower FC was significantly associated with poorer motor performance.
DISCUSSION: Our findings uncover intrinsic differences between times of day and circadian phenotype groups. This suggests that central mechanisms contribute to diurnal variation in motor performance and the functional integrity of the MN at rest influences the ability to perform in a motor task.

PMID: 33577933 [PubMed - as supplied by publisher]

Altered default mode network activity and cortical thickness as vulnerability indicators for SCZ: a preliminary resting state MRI study.

Sat, 02/13/2021 - 19:14
Related Articles

Altered default mode network activity and cortical thickness as vulnerability indicators for SCZ: a preliminary resting state MRI study.

Eur Rev Med Pharmacol Sci. 2021 Jan;25(2):669-677

Authors: Jamea AA, Alblowi M, Alghamdi J, Alosaimi FD, Albadr F, Abualait T, Bashir S

Abstract
OBJECTIVE: Alterations in brain function in patients with schizophrenia (SCZ) and other neuropsychiatric disorders are evident not only during specific cognitive challenges, but also from functional MRI data obtained during a resting state. Patients with chronic SCZ have shown deficits in default mood network (DMN) and gray matter volume in resting-state functional magnetic resonance imaging (rs-fMRI). However, cortical thickness and surface area in first-episode schizophrenic patients have rarely been investigated.
PATIENTS AND METHODS: In the present study, we applied independent component analysis (ICA) to a series of rs-fMRIs of 15 SCZ patients and 15 matched healthy controls. The data were analyzed using MELODIC of FMRIB's Software Library (FSL version 5.9; www.fmrib.ox.ac.uk/fsl) to identify large-scale patterns of temporal signal-intensity coherence.
RESULTS: Patients with SCZ showed significantly higher functional connectivity in the DMN, auditory network, and cerebellum network (p=0.049, p=0.05, and p=0.007, respectively) than matched healthy controls. The patients also exhibited significantly less cortical thickness, primarily in the bilateral prefrontal and parietal cortex, and higher thickness in the bilateral anterior temporal lobes, left medial orbitofrontal cortex, and left cuneus than the matched healthy controls.
CONCLUSIONS: These results indicate that significantly abnormal DMN connectivity and cortical thickness contribute to local functional pathology in patients with SCZ.

PMID: 33577021 [PubMed - as supplied by publisher]

Altered Complexity of Spontaneous Brain Activity in Schizophrenia and Bipolar Disorder Patients.

Sat, 02/13/2021 - 19:14
Related Articles

Altered Complexity of Spontaneous Brain Activity in Schizophrenia and Bipolar Disorder Patients.

J Magn Reson Imaging. 2021 Feb 11;:

Authors: Zhang N, Niu Y, Sun J, An W, Li D, Wei J, Yan T, Xiang J, Wang B

Abstract
BACKGROUND: Schizophrenia (SC) and bipolar disorder (BP) share elements of symptoms and the underlying neural mechanisms for both remain unclear. Recently, the complexity of spontaneous functional MRI (fMRI) signals in brain activity has been investigated in SC and BP using multiscale sample entropy (MSE) with inconsistent results.
PURPOSE: To perform MSE analysis across five time scales to assess differences in resting-state fMRI signal complexity in SC, BP, and normal controls (NC).
STUDY TYPE: Retrospective.
POPULATION: Fifty SC, 49 BP, and 49 NC.
FIELD STRENGTH/SEQUENCE: A 3 T, T2* weighted echo planar imaging (EPI) sequence.
ASSESSMENT: The mean MSEs of all gray matter (GM) and of 12 regions of interest (ROIs) were extracted using masks across the five scales. The regional homogeneity (ReHo) and amplitude of low-frequency fluctuation (ALFF) in these ROIs were also determined and the relationship between the three measures was investigated. The correlations between cognitive assessment scores and MSE values were also explored.
STATISTICAL TESTS: Bonferroni correction, One-way ANOVA, Spearman rank correlation coefficient (r), Gaussian random field (GRF) correction.
RESULTS: There were decreased GM MSE values in the patient groups (F = 9.629, P < 0.05). SC and BP patients demonstrated lower complexity than NCs in the calcarine fissure, precuneus, inferior occipital gyrus, lingual gyrus and cerebellum, and higher complexity in the median cingulate, thalamus, hippocampus, middle temporal gyrus and middle frontal gyrus. There were significant differences between SC and BP patients in the precuneus (F = 4.890, P < 0.05) and inferior occipital gyrus (F = 5.820, P < 0.05). Calcarine fissure, cingulate, temporal gyrus, occipital gyrus, hippocampus, precuneus, frontal gyrus, and lingual gyrus MSE values were significantly correlated with both ReHo (r > 0.282, P < 0.05) and ALFF (r > 0.278, P < 0.05). Furthermore, median temporal MSE (r = -0.321, P < 0.05) on scale 3 and (r = -0.307, P < 0.05) on scale 4 and median cingulate MSE (r = -0.337, P < 0.05) on scale 5 was significantly negatively correlated with cognitive assessment scores.
DATA CONCLUSION: These data highlight different patterns of brain signal intensity complexity in SC and BP.
LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY: Stage 1.

PMID: 33576137 [PubMed - as supplied by publisher]

Reliability modelling of resting-state functional connectivity

Sat, 02/13/2021 - 19:00

Neuroimage. 2021 Feb 11;231:117842. doi: 10.1016/j.neuroimage.2021.117842. Online ahead of print.

ABSTRACT

Resting-state functional magnetic resonance imaging (rs-fMRI) has an inherently low signal-to-noise ratio largely due to thermal and physiological noise that attenuates the functional connectivity (FC) estimates. Such attenuation limits the reliability of FC and may bias its association with other traits. Low reliability also limits heritability estimates. Classical test theory can be used to obtain a true correlation estimate free of random measurement error from parallel tests, such as split-half sessions of a rs-fMRI scan. We applied a measurement model to split-half FC estimates from the resting-state fMRI data of 1003 participants from the Human Connectome Project (HCP) to examine the benefit of reliability modelling of FC in association with traits from various domains. We evaluated the efficiency of the measurement model on extracting a stable and reliable component of FC and its association with several traits for various sample sizes and scan durations. In addition, we aimed to replicate our previous findings of increased heritability estimates when using a measurement model in a longitudinal adolescent twin cohort. The split-half measurement model improved test-retest reliability of FC on average with +0.33 points (from +0.49 to +0.82), improved strength of associations between FC and various traits on average 1.2-fold (range 1.09-1.35), and increased heritability estimates on average with +20% points (from 39% to 59%) for the full HCP dataset. On average, about half of the variance in split-session FC estimates was attributed to the stable and reliable component of FC. Shorter scan durations showed greater benefit of reliability modelling (up to 1.6-fold improvement), with an additional gain for smaller sample sizes (up to 1.8-fold improvement). Reliability modelling of FC based on a split-half using a measurement model can benefit genetic and behavioral studies by extracting a stable and reliable component of FC that is free from random measurement error and improves genetic and behavioral associations.

PMID:33581291 | DOI:10.1016/j.neuroimage.2021.117842

Intermittent theta burst stimulation for negative symptoms of schizophrenia-A double-blind, sham-controlled pilot study

Sat, 02/13/2021 - 19:00

NPJ Schizophr. 2021 Feb 12;7(1):10. doi: 10.1038/s41537-021-00138-3.

ABSTRACT

Optimal noninvasive brain stimulation parameters for the treatment of negative symptoms of schizophrenia remain unclear. Here, we aimed to investigate the clinical and biological effects of intermittent theta burst transcranial magnetic stimulation (iTBS) in patients with treatment-resistant negative symptoms of schizophrenia (NCT00875498). In a randomized sham-controlled 2-arm study, 22 patients with schizophrenia and treatment-resistant negative symptoms received 20 sessions of either active (n = 12) or sham (n = 10) iTBS. Sessions were delivered twice a day on 10 consecutive working days. Negative symptom severity was assessed 5 times using the Scale for the Assessment of Negative Symptoms (SANS): before iTBS, after iTBS, and 1, 3, and 6 months after iTBS. As a secondary objective, we explored the acute effects of iTBS on functional connectivity of the left dorsolateral prefrontal cortex (DLPFC) using seed-based resting-state functional connectivity MRI (rsFC fMRI) images acquired before and after iTBS. Active iTBS over the left DLPFC significantly decreased negative symptoms severity compared to sham iTBS (F(3,60) = 3.321, p = 0.026). Post hoc analyses revealed that the difference between groups was significant 6 months after the end of stimulation sessions. Neuroimaging revealed an increase in rsFC between the left DLPFC and a brain region encompassing the right lateral occipital cortex and right angular gyrus and a right midbrain region that may encompass dopamine neuron cell bodies. Thus, iTBS over the left DLPFC can alleviate negative symptoms of schizophrenia. The effect might be driven by significant modulation of dopamine transmission.

PMID:33580032 | DOI:10.1038/s41537-021-00138-3

Correlation between cortical gene expression and resting-state functional network centrality in healthy young adults.

Fri, 02/12/2021 - 19:13
Related Articles

Correlation between cortical gene expression and resting-state functional network centrality in healthy young adults.

Hum Brain Mapp. 2021 Feb 11;:

Authors: Zhu D, Yuan T, Gao J, Xu Q, Xue K, Zhu W, Tang J, Liu F, Wang J, Yu C

Abstract
Resting-state functional connectivity in the human brain is heritable, and previous studies have investigated the genetic basis underlying functional connectivity. However, at present, the molecular mechanisms associated with functional network centrality are still largely unknown. In this study, functional networks were constructed, and the graph-theory method was employed to calculate network centrality in 100 healthy young adults from the Human Connectome Project. Specifically, functional connectivity strength (FCS), also known as the "degree centrality" of weighted networks, is calculated to measure functional network centrality. A multivariate technique of partial least squares regression (PLSR) was then conducted to identify genes whose spatial expression profiles best predicted the FCS distribution. We found that FCS spatial distribution was significantly positively correlated with the expression of genes defined by the first PLSR component. The FCS-related genes we identified were significantly enriched for ion channels, axon guidance, and synaptic transmission. Moreover, FCS-related genes were preferentially expressed in cortical neurons and young adulthood and were enriched in numerous neurodegenerative and neuropsychiatric disorders. Furthermore, a series of validation and robustness analyses demonstrated the reliability of the results. Overall, our results suggest that the spatial distribution of FCS is modulated by the expression of a set of genes associated with ion channels, axon guidance, and synaptic transmission.

PMID: 33570215 [PubMed - as supplied by publisher]

Dynamics and Concordance Abnormalities Among Indices of Intrinsic Brain Activity in Individuals With Subjective Cognitive Decline: A Temporal Dynamics Resting-State Functional Magnetic Resonance Imaging Analysis.

Fri, 02/12/2021 - 19:13
Related Articles

Dynamics and Concordance Abnormalities Among Indices of Intrinsic Brain Activity in Individuals With Subjective Cognitive Decline: A Temporal Dynamics Resting-State Functional Magnetic Resonance Imaging Analysis.

Front Aging Neurosci. 2020;12:584863

Authors: Yang Y, Zha X, Zhang X, Ke J, Hu S, Wang X, Su Y, Hu C

Abstract
Individuals with subjective cognitive decline (SCD) are more likely to develop into Alzheimer disease (AD) in the future. Resting-state functional magnetic resonance imaging (rs-fMRI) studies have shown alterations of intrinsic brain activity (IBA) in SCD individuals. However, rs-fMRI studies to date have mainly focused on static characteristics of IBA, with few studies reporting dynamics- and concordance-related changes in IBA indices in SCD individuals. To investigate these aberrant changes, a temporal dynamic analysis of rs-fMRI data was conducted on 94 SCD individuals (71.07 ± 6.18 years, 60 female), 75 (74.36 ± 8.42 years, 35 female) mild cognitive impairment (MCI) patients, and 82 age-, gender-, and education-matched controls (NCs; 73.88 ± 7.40 years, 49 female) from the Alzheimer's Disease Neuroimaging Initiative database. The dynamics and concordance of the rs-fMRI indices were calculated. The results showed that SCD individuals had a lower amplitude of low-frequency fluctuations dynamics in bilateral hippocampus (HP)/parahippocampal gyrus (PHG)/fusiform gyrus (FG) and bilateral cerebellum, a lower fractional amplitude of low-frequency fluctuation dynamics in bilateral precuneus (PreCu) and paracentral lobule, and a lower regional homogeneity dynamics in bilateral cerebellum, vermis, and left FG compared with the other two groups, whereas those in MCI patients were higher (Gaussian random field-corrected, voxel-level P < 0.001, cluster-level P < 0.05). Furthermore, SCD individuals had higher concordance in bilateral HP/PHG/FG, temporal lobe, and left midcingulate cortex than NCs, but those in MCI were lower than those in NCs. No correlation between concordance values and neuropsychological scale scores was found. SCD individuals showed both dynamics and concordance-related alterations in IBA, which indicates a compensatory mechanism in SCD individuals. Temporal dynamics analysis offers a novel approach to capturing brain alterations in individuals with SCD.

PMID: 33568986 [PubMed]

Jumping over baselines with new methods to predict activation maps from resting-state fMRI.

Fri, 02/12/2021 - 19:13
Related Articles

Jumping over baselines with new methods to predict activation maps from resting-state fMRI.

Sci Rep. 2021 Feb 10;11(1):3480

Authors: Lacosse E, Scheffler K, Lohmann G, Martius G

Abstract
Cognitive fMRI research primarily relies on task-averaged responses over many subjects to describe general principles of brain function. Nonetheless, there exists a large variability between subjects that is also reflected in spontaneous brain activity as measured by resting state fMRI (rsfMRI). Leveraging this fact, several recent studies have therefore aimed at predicting task activation from rsfMRI using various machine learning methods within a growing literature on 'connectome fingerprinting'. In reviewing these results, we found lack of an evaluation against robust baselines that reliably supports a novelty of predictions for this task. On closer examination to reported methods, we found most underperform against trivial baseline model performances based on massive group averaging when whole-cortex prediction is considered. Here we present a modification to published methods that remedies this problem to large extent. Our proposed modification is based on a single-vertex approach that replaces commonly used brain parcellations. We further provide a summary of this model evaluation by characterizing empirical properties of where prediction for this task appears possible, explaining why some predictions largely fail for certain targets. Finally, with these empirical observations we investigate whether individual prediction scores explain individual behavioral differences in a task.

PMID: 33568695 [PubMed - in process]

How to Interpret Resting-State fMRI: Ask Your Participants.

Fri, 02/12/2021 - 19:13
Related Articles

How to Interpret Resting-State fMRI: Ask Your Participants.

J Neurosci. 2021 Feb 10;41(6):1130-1141

Authors: Gonzalez-Castillo J, Kam JWY, Hoy CW, Bandettini PA

Abstract
Resting-state fMRI (rsfMRI) reveals brain dynamics in a task-unconstrained environment as subjects let their minds wander freely. Consequently, resting subjects navigate a rich space of cognitive and perceptual states (i.e., ongoing experience). How this ongoing experience shapes rsfMRI summary metrics (e.g., functional connectivity) is unknown, yet likely to contribute uniquely to within- and between-subject differences. Here we argue that understanding the role of ongoing experience in rsfMRI requires access to standardized, temporally resolved, scientifically validated first-person descriptions of those experiences. We suggest best practices for obtaining those descriptions via introspective methods appropriately adapted for use in fMRI research. We conclude with a set of guidelines for fusing these two data types to answer pressing questions about the etiology of rsfMRI.

PMID: 33568446 [PubMed - in process]

Brain Structure and Function of Chronic Low Back Pain Patients on Long-Term Opioid Analgesic Treatment: A Preliminary Study.

Fri, 02/12/2021 - 19:13
Related Articles

Brain Structure and Function of Chronic Low Back Pain Patients on Long-Term Opioid Analgesic Treatment: A Preliminary Study.

Mol Pain. 2021 Jan-Dec;17:1744806921990938

Authors: Murray K, Lin Y, Makary MM, Whang PG, Geha P

Abstract
Chronic low back pain (CLBP) is often treated with opioid analgesics (OA), a class of medications associated with a significant risk of misuse. However, little is known about how treatment with OA affect the brain in chronic pain patients. Gaining this knowledge is a necessary first step towards understanding OA associated analgesia and elucidating long-term risk of OA misuse. Here we study CLBP patients chronically medicated with opioids without any evidence of misuse and compare them to CLBP patients not on opioids and to healthy controls using structural and functional brain imaging. CLBP patients medicated with OA showed loss of volume in the nucleus accumbens and thalamus, and an overall significant decrease in signal to noise ratio in their sub-cortical areas. Power spectral density analysis (PSD) of frequency content in the accumbens' resting state activity revealed that both medicated and unmedicated patients showed loss of PSD within the slow-5 frequency band (0.01-0.027 Hz) while only CLBP patients on OA showed additional density loss within the slow-4 frequency band (0.027-0.073 Hz). We conclude that chronic treatment with OA is associated with altered brain structure and function within sensory limbic areas.

PMID: 33567986 [PubMed - in process]