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1.
Sci Rep ; 14(1): 1380, 2024 01 16.
Article in English | MEDLINE | ID: mdl-38228703

ABSTRACT

Oxytocin (OXT) is known to modulate social behavior and cognition and has been discussed as pathophysiological and therapeutic factor for autism spectrum disorder (ASD). An accumulating body of evidence indicates the hypothalamus to be of particular importance with regard to the underlying neurobiology. Here we used a region of interest voxel-based morphometry (VBM) approach to investigate hypothalamic gray matter volume (GMV) in autistic (n = 29, age 36.03 ± 11.0) and non-autistic adults (n = 27, age 30.96 ± 11.2). Peripheral plasma OXT levels and the autism spectrum quotient (AQ) were used for correlation analyses. Results showed no differences in hypothalamic GMV in autistic compared to non-autistic adults but suggested a differential association between hypothalamic GMV and OXT levels, such that a positive association was found for the ASD group. In addition, hypothalamic GMV showed a positive association with autistic traits in the ASD group. Bearing in mind the limitations such as a relatively small sample size, a wide age range and a high rate of psychopharmacological treatment in the ASD sample, these results provide new preliminary evidence for a potentially important role of the HTH in ASD and its relationship to the OXT system, but also point towards the importance of interindividual differences.


Subject(s)
Autism Spectrum Disorder , Autistic Disorder , Adult , Humans , Middle Aged , Young Adult , Autistic Disorder/complications , Gray Matter/diagnostic imaging , Autism Spectrum Disorder/complications , Oxytocin , Cross-Sectional Studies , Secondary Data Analysis , Hypothalamus/diagnostic imaging
2.
Complement Ther Clin Pract ; 54: 101825, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38169278

ABSTRACT

PURPOSE: This study aimed to investigate the relationship between physical fitness, gray matter volume (GMV), and autism severity in children with autism spectrum disorder (ASD). Besides, we sought to diagnose autism severity associated with physical fitness and GMV using machine learning methods. METHODS: Ninety children diagnosed with ASD underwent physical fitness tests, magnetic resonance imaging scans, and autism severity assessments. Diagnosis models were established using extreme gradient boosting (XGB), random forest (RF), support vector machine (SVM), and decision tree (DT) algorithms. Hyperparameters were optimized through the grid search cross-validation method. The shapley additive explanation (SHAP) method was employed to explain the diagnosis results. RESULTS: Our study revealed associations between muscular strength in physical fitness and GMV in specific brain regions (left paracentral lobule, bilateral thalamus, left inferior temporal gyrus, and cerebellar vermis I-II) with autism severity in children with ASD. The accuracy (95 % confidence interval) of the XGB, RF, SVM, and DT models were 77.9 % (77.3, 78.6 %), 72.4 % (71.7, 73.2 %), 71.9 % (71.1, 72.6 %), and 66.9 % (66.2, 67.7 %), respectively. SHAP analysis revealed that muscular strength and thalamic GMV significantly influenced the decision-making process of the XGB model. CONCLUSION: Machine learning methods can effectively diagnose autism severity associated with physical fitness and GMV in children with ASD. In this respect, the XGB model demonstrated excellent performance across various indicators, suggesting its potential for diagnosing autism severity.


Subject(s)
Autism Spectrum Disorder , Autistic Disorder , Child , Humans , Gray Matter/diagnostic imaging , Gray Matter/pathology , Autism Spectrum Disorder/diagnostic imaging , Autism Spectrum Disorder/pathology , Machine Learning , Physical Fitness
3.
Epilepsia ; 65(1): e1-e6, 2024 Jan.
Article in English | MEDLINE | ID: mdl-37945542

ABSTRACT

Recent morphometric magnetic resonance imaging (MRI) studies suggested the possibility that valproate (VPA) use is associated with parieto-occipital cortical thinning in patients with heterogeneous epilepsy syndromes. In this study, we examined the effect of VPA on the brain volume using a large number of homogenous patients with idiopathic generalized epilepsy. Voxel-based morphometry was used to compare regional gray matter (GM) volume between 112 patients currently taking VPA (VPA+ group), 81 patients not currently taking VPA (VPA- group), and 120 healthy subjects (control group). The VPA+ group showed a significant GM volume reduction in the bilateral cerebellum, hippocampus, insula, caudate nucleus, medial frontal cortex/anterior cingulate cortex, primary motor/premotor cortex, medial occipital cortex, and anteromedial thalamus, as compared to the control group. The VPA- group showed a significant GM volume reduction in the anteromedial thalamus and right hippocampus/temporal cortex, as compared to the control group. Compared to the VPA- group, the VPA+ group had a significant GM volume reduction in the bilateral cerebellum, primary motor/premotor cortex, and medial frontal cortex/anterior cingulate cortex. We have provided evidence that VPA use could result in GM volume reductions in the frontal cortex and cerebellum. Our findings should be acknowledged as a potential confounding factor in morphometric MRI studies that include subjects taking VPA.


Subject(s)
Epilepsy, Generalized , Gray Matter , Humans , Gray Matter/diagnostic imaging , Gray Matter/pathology , Valproic Acid/adverse effects , Epilepsy, Generalized/pathology , Cerebral Cortex , Frontal Lobe/diagnostic imaging , Frontal Lobe/pathology , Magnetic Resonance Imaging/methods , Brain/pathology
4.
Sci Rep ; 13(1): 18469, 2023 10 27.
Article in English | MEDLINE | ID: mdl-37891243

ABSTRACT

Mindfulness has become increasingly popular and the practice presents in many different forms. Research has been growing extensively with benefits shown across various outcomes. However, there is a lack of consensus over the efficacy of randomized controlled mindfulness interventions, both traditional and mind-body formats. This study aimed to investigate the structural brain changes in mindfulness-based interventions through a meta-analysis. Scopus, PubMed, Web of Science, and PsycINFO were searched up to April 2023. 11 studies (n = 581) assessing whole-brain voxel-based grey matter or cortical thickness changes after a mindfulness RCT were included. Anatomical likelihood estimation was used to carry out voxel-based meta-analysis with leave-one-out sensitivity analysis and behavioural analysis as follow-ups. One significant cluster (p < 0.001, Z = 4.76, cluster size = 632 mm3) emerged in the right insula and precentral gyrus region (MNI = 48, 10, 4) for structural volume increases in intervention group compared to controls. Behavioural analysis revealed that the cluster was associated with mental processes of attention and somesthesis (pain). Mindfulness interventions have the ability to affect neural plasticity in areas associated with better pain modulation and increased sustained attention. This further cements the long-term benefits and neuropsychological basis of mindfulness-based interventions.


Subject(s)
Mindfulness , Humans , Randomized Controlled Trials as Topic , Brain/diagnostic imaging , Pain , Gray Matter/diagnostic imaging
5.
Neuroimage ; 280: 120357, 2023 10 15.
Article in English | MEDLINE | ID: mdl-37661080

ABSTRACT

A sensitive and accurate imaging technique capable of tracking the disease progression of Alzheimer's Disease (AD) driven amnestic dementia would be beneficial. A currently available method for pathology detection in AD with high accuracy is Positron Emission Tomography (PET) imaging, despite certain limitations such as low spatial resolution, off-targeting error, and radiation exposure. Non-invasive MRI scanning with quantitative magnetic susceptibility measurements can be used as a complementary tool. To date, quantitative susceptibility mapping (QSM) has widely been used in tracking deep gray matter iron accumulation in AD. The present work proposes that by compartmentalizing quantitative susceptibility into paramagnetic and diamagnetic components, more holistic information about AD pathogenesis can be acquired. Particularly, diamagnetic component susceptibility (DCS) can be a powerful indicator for tracking protein accumulation in the gray matter (GM), demyelination in the white matter (WM), and relevant changes in the cerebrospinal fluid (CSF). In the current work, voxel-wise group analysis of the WM and the CSF regions show significantly lower |DCS| (the absolute value of DCS) value for amnestic dementia patients compared to healthy controls. Additionally, |DCS| and τ PET standardized uptake value ratio (SUVr) were found to be associated in several GM regions typically affected by τ deposition in AD. Therefore, we propose that the separated diamagnetic susceptibility can be used to track pathological neurodegeneration in different tissue types and regions of the brain. With the initial evidence, we believe the usage of compartmentalized susceptibility demonstrates substantive potential as an MRI-based technique for tracking AD-driven neurodegeneration.


Subject(s)
Alzheimer Disease , Humans , Alzheimer Disease/diagnostic imaging , Brain/diagnostic imaging , Cerebral Cortex , Disease Progression , Gray Matter/diagnostic imaging
6.
Psychiatry Res Neuroimaging ; 335: 111706, 2023 10.
Article in English | MEDLINE | ID: mdl-37651834

ABSTRACT

As a key center for sensory information processing and transmission, the thalamus plays a crucial role in the development of posttraumatic stress disorder (PTSD). However, the changes in the thalamus and its role in regulating different PTSD symptoms remain unclear. In this study, fourteen PTSD patients and eighteen healthy controls (HCs) were recruited. All subjects underwent whole-brain T1-weighted three-dimensional Magnetization Prepared Rapid Gradient Echo Imaging scans. Gray matter volume (GMV) in the thalamus and its subregions were estimated using voxel-based morphometry (VBM). Compared to HCs, PTSD patients exhibited significant GMV reduction in the left thalamus and its subregions, including anterior, mediodorsal, ventral-lateral-dorsal (VLD), ventral-anterior, and ventral-lateral-ventral (VLV). Among the significantly reduced thalamic subregions, we found positive correlations between the GMV values of the left VLD and VLV and the re-experiencing symptoms score, arousal symptoms score, and total CAPS score. When using the symptom-related GMV values of left VLV and VLD in combination as a predictor, receiver operating characteristic (ROC) analysis revealed that the area under the curve (AUC) for binary classification reached 0.813. This study highlights the neurobiological mechanisms of PTSD related to thalamic changes and may provide potential imaging markers for diagnosis and therapy targets.


Subject(s)
Stress Disorders, Post-Traumatic , Humans , Stress Disorders, Post-Traumatic/diagnostic imaging , Magnetic Resonance Imaging/methods , Brain , Gray Matter/diagnostic imaging , Thalamus/diagnostic imaging
7.
Hum Brain Mapp ; 44(15): 5167-5179, 2023 10 15.
Article in English | MEDLINE | ID: mdl-37605825

ABSTRACT

In this article, we focus on estimating the joint relationship between structural magnetic resonance imaging (sMRI) gray matter (GM), and multiple functional MRI (fMRI) intrinsic connectivity networks (ICNs). To achieve this, we propose a multilink joint independent component analysis (ml-jICA) method using the same core algorithm as jICA. To relax the jICA assumption, we propose another extension called parallel multilink jICA (pml-jICA) that allows for a more balanced weight distribution over ml-jICA/jICA. We assume a shared mixing matrix for both the sMRI and fMRI modalities, while allowing for different mixing matrices linking the sMRI data to the different ICNs. We introduce the model and then apply this approach to study the differences in resting fMRI and sMRI data from patients with Alzheimer's disease (AD) versus controls. The results of the pml-jICA yield significant differences with large effect sizes that include regions in overlapping portions of default mode network, and also hippocampus and thalamus. Importantly, we identify two joint components with partially overlapping regions which show opposite effects for AD versus controls, but were able to be separated due to being linked to distinct functional and structural patterns. This highlights the unique strength of our approach and multimodal fusion approaches generally in revealing potentially biomarkers of brain disorders that would likely be missed by a unimodal approach. These results represent the first work linking multiple fMRI ICNs to GM components within a multimodal data fusion model and challenges the typical view that brain structure is more sensitive to AD than fMRI.


Subject(s)
Functional Neuroimaging , Gray Matter , Alzheimer Disease/diagnostic imaging , Alzheimer Disease/physiopathology , Rest , Magnetic Resonance Imaging/methods , Humans , Gray Matter/diagnostic imaging , Male , Female , Middle Aged , Aged , Aged, 80 and over , Hippocampus/diagnostic imaging , Thalamus/diagnostic imaging , Functional Neuroimaging/methods
8.
Mult Scler Relat Disord ; 77: 104853, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37473593

ABSTRACT

BACKGROUND: Multiple Sclerosis (MS) is a chronic neuroinflammatory disease that affects the central nervous system. Asymmetry is one of the finding in brain MRI of these patients, which is related to the debilitating symptoms of the disease. This study aimed to investigate and compare the thalamic asymmetry in MS patients and its relationship with other MRI and clinical findings of these patients. METHODS: This cross-sectional study conducted on 83 patients with relapse-remitting MS (RRMS), 43 patients with secondary progressive MS (SPMS), and 89 healthy controls. The volumes of total intracranial, total gray matter, total white matter, lesions, thalamus, and also the thalamic asymmetry indices were calculated. The 9-hole peg test (9-HPT) and Expanded Disability Status Scale (EDSS) were assessed as clinical findings. RESULTS: We showed that the normalized whole thalamic volume in healthy subjects was higher than MS patients (both RRMS and SPMS). Thalamic asymmetry index (TAI) was significantly different between RRMS patients and SPMS patients (p = 0.011). The absolute value of TAI was significantly lower in healthy subjects than in RRMS (p < 0.001) and SPMS patients (p < 0.001), and SPMS patients had a higher absolute TAI compared to RRMS patients (p = 0.037). CONCLUSIONS: In this cross-sectional study we showed a relationship between normalized whole thalamic volume and MS subtype. Also, we showed that the asymmetric indices of the thalamus can be related to the progression of the disease. Eventually, we showed that thalamic asymmetry can be related to the disease progression and subtype changes in MS.


Subject(s)
Multiple Sclerosis, Chronic Progressive , Multiple Sclerosis, Relapsing-Remitting , Multiple Sclerosis , Humans , Multiple Sclerosis/complications , Multiple Sclerosis/diagnostic imaging , Multiple Sclerosis/pathology , Cross-Sectional Studies , Multiple Sclerosis, Chronic Progressive/diagnostic imaging , Multiple Sclerosis, Chronic Progressive/pathology , Gray Matter/diagnostic imaging , Gray Matter/pathology , Magnetic Resonance Imaging , Thalamus/diagnostic imaging , Atrophy/pathology , Multiple Sclerosis, Relapsing-Remitting/complications , Multiple Sclerosis, Relapsing-Remitting/diagnostic imaging , Multiple Sclerosis, Relapsing-Remitting/pathology , Brain/pathology
9.
Int J Psychol ; 58(4): 360-367, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37012075

ABSTRACT

The ability to make suitable risky decision is necessary for individuals' survival and development. However, individuals vary in risk preference. The current study, adopting a decision task, aimed to explore the emotional sensitivity to missed opportunity and grey matter volume (GMV) of thalamus in high risk-takers by using voxel-based morphology analysis. In the task, eight boxes should be opened successively. Seven boxes contained coins and one box contained the devil to zero coins. Once stopped, collected and missed (missed opportunity) coins were presented. Participants were divided into high- and low risk-takers according to their risk-taking behaviour in the decision task. We found that high risk-takers showed stronger emotional sensitivity to missed opportunity and smaller GMV of thalamus than low risk-takers. In addition, the GMV of thalamus partially mediated the effect of emotional sensitivity to missed opportunity on risk-taking behaviour among all participants. Overall, the current study highlights the role of emotional sensitivity to missed opportunity and the GMV of thalamus in risk-taking behaviour, which helps us understand the possible reason for the variation among individuals in risk preference.


Subject(s)
Gray Matter , Magnetic Resonance Imaging , Humans , Gray Matter/diagnostic imaging , Thalamus/diagnostic imaging , Risk-Taking , Brain
10.
Neuromodulation ; 26(8): 1705-1713, 2023 Dec.
Article in English | MEDLINE | ID: mdl-35088745

ABSTRACT

BACKGROUND: The dentato-rubro-thalamic tract (DRT) is currently considered as a potential target in deep brain stimulation (DBS) for various types of tremor. However, tractography depiction can vary depending on the included brain regions. The fast gray matter acquisition T1 inversion recovery (FGATIR) sequence, with excellent delineation of gray and white matter, possibly provides anatomical identification of rubro-thalamic DRT fibers. OBJECTIVE: This study aimed to evaluate the FGATIR sequence by comparison with DRT depiction, electrode localization, and effectiveness of DBS therapy. MATERIALS AND METHODS: In patients with DBS therapy because of medication-refractory tremor, the FGATIR sequence was evaluated for depiction of the thalamus, red nucleus (RN), and rubro-thalamic connections. Deterministic tractography of the DRT, electrode localization, and tremor control were compared. The essential tremor rating scale was used to assess (hand) tremor. Tremor control was considered successful when complete tremor suppression (grade 0) or almost complete suppression (grade 1) was observed. RESULTS: In the postoperative phase, we evaluated 14 patients who underwent DRT-guided DBS: 12 patients with essential tremor, one with tremor-dominant Parkinson disease, and one with multiple sclerosis, representing 24 trajectories. Mean follow-up was 11.3 months (range 6-19 months). The FGATIR sequence provided a clear delineation of a hypointense white matter tract within the hyperintense thalamus. In coronal plane, this tract was most readily recognizable as a "rubral wing," with the round RN as base and lateral triangular convergence. The deterministic DRT depiction was consistently situated within the rubral wing. The number of active contacts located within the DRT (and rubral wing) was 22 (92%), of which 16 (73%) showed successful tremor control. CONCLUSIONS: The FGATIR sequence offers visualization of the rubro-thalamic connections that form the DRT, most readily recognizable as a "rubral wing" in coronal plane. This sequence contributes to tractographic depiction of DRT and provides a direct anatomical DBS target area for tremor control.


Subject(s)
Deep Brain Stimulation , Essential Tremor , Humans , Tremor/therapy , Tremor/surgery , Essential Tremor/therapy , Gray Matter/diagnostic imaging , Diffusion Tensor Imaging , Thalamus/diagnostic imaging , Thalamus/surgery
11.
Cereb Cortex ; 33(7): 3664-3673, 2023 03 21.
Article in English | MEDLINE | ID: mdl-35972417

ABSTRACT

The kidney and brain expressed protein (KIBRA) rs17070145 polymorphism is associated with both structure and activation of the olfactory cortex. However, no studies have thus far examined whether KIBRA can be linked with olfactory function and whether brain structure plays any role in the association. We addressed these questions in a population-based cross-sectional study among rural-dwelling older adults. This study included 1087 participants derived from the Multidomain Interventions to Delay Dementia and Disability in Rural China, who underwent the brain MRI scans in August 2018 to October 2020; of these, 1016 took the 16-item Sniffin' Sticks identification test and 634 (62.40%) were defined with olfactory impairment (OI). Data were analyzed using the voxel-based morphometry analysis and general linear, logistic, and structural equation models. The KIBRA rs17070145 C-allele (CC or CT vs. TT genotype) was significantly associated with greater gray matter volume (GMV) mainly in the bilateral orbitofrontal cortex and left thalamus (P < 0.05) and with the multi-adjusted odds ratio of 0.73 (95% confidence interval 0.56-0.95) for OI. The left thalamic GMV could mediate 8.08% of the KIBRA-olfaction association (P < 0.05). These data suggest that the KIBRA rs17070145 C-allele is associated with a reduced likelihood of OI among older adults, partly mediated through left thalamic GMV.


Subject(s)
Gray Matter , Olfaction Disorders , Aged , Humans , Brain , Cerebral Cortex , Cross-Sectional Studies , Gray Matter/diagnostic imaging , Magnetic Resonance Imaging , Thalamus/diagnostic imaging
12.
Neuroimage ; 264: 119722, 2022 12 01.
Article in English | MEDLINE | ID: mdl-36323383

ABSTRACT

The thalamus is heavily involved in relaying sensory signals to the cerebral cortex. A relevant issue is how the deprivation of congenital visual sensory information modulates the development of the thalamocortical network. The answer is unclear because previous studies on this topic did not investigate network development, structure-function combinations, and cognition-related behaviors in the same study. To overcome these limitations, we recruited 30 congenitally blind subjects (8 children, 22 adults) and 31 sighted subjects (10 children, 21 adults), and conducted multiple analyses [i.e., gray matter volume (GMV) analysis using the voxel-based morphometry (VBM) method, resting-state functional connectivity (FC), and brain-behavior correlation]. We found that congenital blindness elicited significant changes in the development of GMV in visual and somatosensory thalamic regions. Blindness also resulted in significant changes in the development of FC between somatosensory thalamic regions and visual cortical regions as well as advanced information processing regions. Moreover, the somatosensory thalamic regions and their FCs with visual cortical regions were reorganized to process high-level tactile language information in blind individuals. These findings provide a refined understanding of the neuroanatomical and functional plasticity of the thalamocortical network.


Subject(s)
Magnetic Resonance Imaging , Visual Cortex , Adult , Child , Humans , Magnetic Resonance Imaging/methods , Visual Cortex/diagnostic imaging , Blindness , Thalamus/diagnostic imaging , Gray Matter/diagnostic imaging
13.
Neuropsychobiology ; 81(6): 531-538, 2022.
Article in English | MEDLINE | ID: mdl-36380634

ABSTRACT

INTRODUCTION: Recently, several mindfulness-based programs showed promising clinical effects in the treatment of psychiatric disorders including substance use disorders. However, very little is known about the effects of mindfulness-based interventions (MBIs) on brain structure in such patients. METHODS: This study aimed to detect changes in gray matter volume (GMV) in opioid-dependent patients receiving MBI during their first month of treatment. Thirty patients were assigned to either 3 weeks of MBI (n = 16) or treatment as usual (TAU, n = 14) and were investigated using structural magnetic resonance imaging before and after treatment. Longitudinal pipeline of the Computational Anatomy Toolbox for SPM (CAT12) was used to detect significant treatment-related changes over time. The identified GMV changes following treatment were related to clinically relevant measures such as impulsivity, distress tolerance, and mindfulness. RESULTS: After treatment, increased mindfulness scores were found in individuals receiving MBI compared to TAU. In the MBI group, there were also significant differences with respect to distress tolerance and impulsivity. Effects on mindfulness, distress tolerance, and impulsivity were also found in the TAU group. Longitudinal within-group analysis revealed increased left anterior insula GMV in individuals receiving MBI. Anterior insula volume increase was associated with decreased impulsivity levels. In the TAU group, significant GMV changes were found in the right lingual gyrus and right entorhinal cortex. DISCUSSION/CONCLUSION: MBI can yield significant clinical effects during early abstinence from opioid dependence. MBI is particularly associated with increased insula GMV, supporting an important role of this region in the context of MBI-induced neural changes.


Subject(s)
Gray Matter , Mindfulness , Opioid-Related Disorders , Humans , Gray Matter/diagnostic imaging , Gray Matter/pathology , Magnetic Resonance Imaging , Opioid-Related Disorders/diagnostic imaging , Opioid-Related Disorders/therapy , Treatment Outcome
14.
Brain Imaging Behav ; 16(6): 2556-2568, 2022 Dec.
Article in English | MEDLINE | ID: mdl-35922652

ABSTRACT

Type 2 diabetes mellitus (T2DM) is associated with brain damage and cognitive decline. Despite the fact that the thalamus involves aspects of cognition and is typically affected in T2DM, existing knowledge of subregion-level thalamic damage and its associations with cognitive performance in T2DM patients is limited. The thalamus was subdivided into 8 subregions in each hemisphere. Resting-state functional and structural MRI data were collected to calculate resting-state functional connectivity (rsFC) and gray matter volume (GMV) of each thalamic subregion in 62 T2DM patients and 50 healthy controls. Compared with controls, T2DM patients showed increased rsFC of the medial pre-frontal thalamus, posterior parietal thalamus, and occipital thalamus with multiple cortical regions. Moreover, these thalamic functional hyperconnectivity were associated with better cognitive performance and lower glucose variability in T2DM patients. However, there were no group differences in GMV for any thalamic subregions. These findings suggest a possible neural compensation mechanism whereby selective thalamocortical functional hyperconnectivity facilitated by better glycemic control help to preserve cognitive ability in T2DM patients, which may ultimately inform intervention and prevention of T2DM-related cognitive decline in real-world clinical settings.


Subject(s)
Cognitive Dysfunction , Diabetes Mellitus, Type 2 , Humans , Magnetic Resonance Imaging , Diabetes Mellitus, Type 2/complications , Diabetes Mellitus, Type 2/diagnostic imaging , Thalamus/diagnostic imaging , Gray Matter/diagnostic imaging
15.
Brain Stimul ; 15(5): 1153-1162, 2022.
Article in English | MEDLINE | ID: mdl-35988862

ABSTRACT

BACKGROUND AND OBJECTIVE: Transcranial direct current stimulation (tDCS) has wide ranging applications in neuro-behavioural and physiological research, and in neurological rehabilitation. However, it is currently limited by substantial inter-subject variability in responses, which may be explained, at least in part, by anatomical differences that lead to variability in the electric field (E-field) induced in the cortex. Here, we tested whether the variability in the E-field in the stimulated cortex during anodal tDCS, estimated using computational simulations, explains the variability in tDCS induced changes in GABA, a neurophysiological marker of stimulation effect. METHODS: Data from five previously conducted MRS studies were combined. The anode was placed over the left primary motor cortex (M1, 3 studies, N = 24) or right temporal cortex (2 studies, N = 32), with the cathode over the contralateral supraorbital ridge. Single voxel spectroscopy was performed in a 2x2x2cm voxel under the anode in all cases. MRS data were acquired before and either during or after 1 mA tDCS using either a sLASER sequence (7T) or a MEGA-PRESS sequence (3T). sLASER MRS data were analysed using LCModel, and MEGA-PRESS using FID-A and Gannet. E-fields were simulated in a finite element model of the head, based on individual structural MR images, using SimNIBS. Separate linear mixed effects models were run for each E-field variable (mean and 95th percentile; magnitude, and components normal and tangential to grey matter surface, within the MRS voxel). The model included effects of time (pre or post tDCS), E-field, grey matter volume in the MRS voxel, and a 3-way interaction between time, E-field and grey matter volume. Additionally, we ran a permutation analysis using PALM to determine whether E-field anywhere in the brain, not just in the MRS voxel, correlated with GABA change. RESULTS: In M1, higher mean E-field magnitude was associated with greater anodal tDCS-induced decreases in GABA (t(24) = 3.24, p = 0.003). Further, the association between mean E-field magnitude and GABA change was moderated by the grey matter volume in the MRS voxel (t(24) = -3.55, p = 0.002). These relationships were consistent across all E-field variables except the mean of the normal component. No significant relationship was found between tDCS-induced GABA decrease and E-field in the temporal voxel. No significant clusters were found in the whole brain analysis. CONCLUSIONS: Our data suggest that the electric field induced by tDCS within the brain is variable, and is significantly related to anodal tDCS-induced decrease in GABA, a key neurophysiological marker of stimulation. These findings strongly support individualised dosing of tDCS, at least in M1. Further studies examining E-fields in relation to other outcome measures, including behaviour, will help determine the optimal E-fields required for any desired effects.


Subject(s)
Motor Cortex , Transcranial Direct Current Stimulation , Brain/diagnostic imaging , Gray Matter/diagnostic imaging , Motor Cortex/diagnostic imaging , Motor Cortex/physiology , Transcranial Direct Current Stimulation/methods , gamma-Aminobutyric Acid
16.
AJNR Am J Neuroradiol ; 43(7): 991-997, 2022 07.
Article in English | MEDLINE | ID: mdl-35798390

ABSTRACT

BACKGROUND AND PURPOSE: Brain iron dyshomeostasis is increasingly recognized as an important contributor to neurodegeneration. Hereditary hemochromatosis is the most commonly inherited disorder of systemic iron overload. Although there is an increasing interest in excessive brain iron deposition, there is a paucity of evidence showing changes in brain iron exceeding that in healthy controls. Quantitative susceptibility mapping and R2* mapping are established MR imaging techniques that we used to noninvasively quantify brain iron in subjects with hereditary hemochromatosis. MATERIALS AND METHODS: Fifty-two patients with hereditary hemochromatosis and 47 age- and sex-matched healthy controls were imaged using a multiecho gradient-echo sequence at 3T. Quantitative susceptibility mapping and R2* data were generated, and regions within the deep gray matter were manually segmented. Mean susceptibility and R2* relaxation rates were calculated for each region, and iron content was compared between the groups. RESULTS: We noted elevated iron levels in patients with hereditary hemochromatosis compared with healthy controls using both R2* and QSM methods in the caudate nucleus, putamen, pulvinar thalamus, red nucleus, and dentate nucleus. Additionally, the substantia nigra showed increased susceptibility while the thalamus showed an increased R2* relaxation rate compared with healthy controls, respectively. CONCLUSIONS: Both quantitative susceptibility mapping and R2* showed abnormal levels of brain iron in subjects with hereditary hemochromatosis compared with controls. Quantitative susceptibility mapping and R2* can be acquired in a single MR imaging sequence and are complementary in quantifying deep gray matter iron.


Subject(s)
Brain Mapping , Hemochromatosis , Brain/diagnostic imaging , Brain Mapping/methods , Gray Matter/diagnostic imaging , Hemochromatosis/diagnostic imaging , Humans , Iron , Magnetic Resonance Imaging/methods
17.
Acta Neurol Belg ; 122(3): 735-743, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35113361

ABSTRACT

PURPOSE: To investigate the impact of Mindfulness-Based Stress Reduction (MBSR) on gray matter volume (GMV) in female breast cancer survivors who suffer from chronic neuropathic pain (CNP). METHODS: Voxel-based morphometry (VBM) was used to explore differences in GMV in 13 MBSR trainees and 10 waitlisted controls, with MRI scans and self-report measures completed pre- and post-8 weeks of training. RESULTS: Compared to controls, the MBSR group had greater GMV in the angular gyrus and middle frontal gyrus post-training. The MBSR group's right parahippocampal gyrus GMV increased from pre- to post-training, whereas the control group's left parahippocampal gyrus, precuneus, middle temporal gyrus, and right cuneus GMV decreased over the same time period. Pain interference was significantly reduced and mindfulness was significantly increased following MBSR for the intervention group only. CONCLUSIONS: MBSR was associated with increased GMV in regions where GMV is known to (1) increase with mindfulness and reorientation of attention and (2) decrease with the experience of chronic neuropathic pain. By contrast, the control group's decreases in GMV may be due to the negative effects of CNP which potentially may be reduced with MBSR, though further research is needed. IMPLICATIONS FOR CANCER SURVIVORS: Given the poor efficiency of pharmacotherapies in a high percentage of women with neuropathic pain following breast cancer treatment, adjunct methods are required. MBSR may affect the brain to help alter attention and perception of pain, thus playing a potentially important role in the path to wellness for breast cancer survivors.


Subject(s)
Breast Neoplasms , Cancer Survivors , Mindfulness , Neuralgia , Breast Neoplasms/complications , Breast Neoplasms/therapy , Female , Gray Matter/diagnostic imaging , Humans , Magnetic Resonance Imaging , Neuralgia/complications , Neuralgia/diagnostic imaging , Neuralgia/therapy , Stress, Psychological/therapy
18.
Neurosci Lett ; 772: 136484, 2022 02 16.
Article in English | MEDLINE | ID: mdl-35108589

ABSTRACT

Occupational burnout has become a pervasive problem, especially among medical professionals who are highly vulnerable to burnout. Since the beginning of the COVID-19 pandemic, medical professionals have faced greater levels of stress. It is critical to increase our understanding of the neurobiological mechanisms of burnout among medical professionals for the benefit of healthcare systems. Therefore, in this study, we investigated structural brain correlates of burnout severity in medical professionals using a voxel-based morphometric technique. Nurses in active service underwent structural magnetic resonance imaging. Two core dimensions of burnout, namely, emotional exhaustion and depersonalization, were assessed using self-reported psychological questionnaires. Levels of emotional exhaustion were found to be negatively correlated with gray matter (GM) volumes in the bilateral ventromedial prefrontal cortex (vmPFC) and left insula. Moreover, levels of depersonalization were negatively correlated with GM volumes in the left vmPFC and left thalamus. Altogether, these findings contribute to a better understanding of the neural mechanisms of burnout and may provide helpful insights for developing effective interventions for medical professionals.


Subject(s)
Brain/diagnostic imaging , Burnout, Professional/diagnostic imaging , Adult , COVID-19 , Cerebral Cortex/diagnostic imaging , Depersonalization , Emotions , Female , Gray Matter/diagnostic imaging , Humans , Image Processing, Computer-Assisted , Magnetic Resonance Imaging , Male , Neuropsychological Tests , Nurses , Pandemics , Prefrontal Cortex/diagnostic imaging , Self Report , Surveys and Questionnaires , Thalamus/diagnostic imaging , Young Adult
19.
J Neuroradiol ; 49(1): 66-72, 2022 Jan.
Article in English | MEDLINE | ID: mdl-32540338

ABSTRACT

OBJECTIVE: To investigate structural and functional alterations in patients with idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD) compared with healthy controls. METHODS: Twenty-seven patients with polysomnography-confirmed iRBD and 33 healthy subjects were recruited. All subjects underwent a 3-tesla structural and resting-state functional magnetic resonance imaging (fMRI) examination. Voxel-based morphometry (VBM) analysis was performed to assess grey matter alterations between groups. The amplitude of low-frequency fluctuations (ALFF) was calculated and then compared to measure differences in spontaneous brain activity. Correlations were performed to explore associations between imaging metrics and clinical characteristics in iRBD patients. RESULTS: Compared with healthy controls, patients with iRBD had decreased grey matter volume in the frontal, temporal, parietal, occipital cortices as well as increased grey matter volume in cerebellum posterior lobe, putamen, and thalamus. Patients with iRBD also exhibited increased ALFF values in the right parahippocampal gyrus. Olfaction correlated with ALFF value changes in occipital cortices. CONCLUSIONS: Patients with iRBD had widespread decreases of grey matter volume. Increases of grey matter volume in cerebellum, putamen, and thalamus may suggest a compensatory effect, while the altered ALFF values in parahippocampal gyrus and occipital cortices may play a role in the underlying process of neurodegeneration in this disorder.


Subject(s)
REM Sleep Behavior Disorder , Brain/diagnostic imaging , Gray Matter/diagnostic imaging , Humans , Magnetic Resonance Imaging , REM Sleep Behavior Disorder/diagnostic imaging , Thalamus
20.
Mult Scler ; 28(4): 550-560, 2022 Apr.
Article in English | MEDLINE | ID: mdl-34378437

ABSTRACT

BACKGROUND: The underlying pathogenesis of surface-in grey matter abnormalities in MS, demonstrated by both neuropathology and advanced MRI analyses, is under investigation and it might be related to CSF-mediated mechanism of inflammation and/or damage. OBJECTIVE: To examine the link of CSF inflammatory profile with the damage of three regions early-involved in MS and bordering with CSF: thalamus, hippocampus and cerebellum. METHODS: In this longitudinal, prospective study, we evaluated, in 109 relapsing-remitting MS patients, at diagnosis and after 2-year follow-up, the association between the baseline CSF level of 19 inflammatory mediators and the volume changes of thalamus, hippocampus, cerebellar cortex and control regions (globus pallidus, putamen). RESULTS: The multivariable analysis showed that the CXCL13 and sCD163 CSF levels at baseline were independent predictors of thalamus (Rmodel2=0.80; p < 0.001) and hippocampus (Rmodel2=0.47; p < 0.001) volume change after 2-year follow-up. These molecules, plus CCL25, IFN-γ and fibrinogen, were independent predictors of the cerebellar cortex volume loss (Rmodel2=0.60; p < 0.001). No independent predictors of volume changes of the control regions were found. CONCLUSION: Our results indicate an association between the CSF inflammatory profile and grey matter volume loss of regions anatomically close to CSF boundaries, thus supporting the hypothesis of a surface-in GM damage in MS.


Subject(s)
Multiple Sclerosis, Relapsing-Remitting , Atrophy/pathology , Brain/pathology , Cerebellum/diagnostic imaging , Cerebellum/pathology , Gray Matter/diagnostic imaging , Gray Matter/pathology , Hippocampus/diagnostic imaging , Hippocampus/pathology , Humans , Magnetic Resonance Imaging , Multiple Sclerosis, Relapsing-Remitting/pathology , Prospective Studies , Thalamus/diagnostic imaging , Thalamus/pathology
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