Disbalanced recruitment of crossed and uncrossed cerebello-thalamic pathways during deep brain stimulation is predictive of delayed therapy escape in essential tremor.

BACKGROUND: Thalamic deep brain stimulation (DBS) is an efficacious treatment for drug-resistant essential tremor (ET) and the dentato-rubro-thalamic tract (DRT) constitutes an important target structure. However, up to 40% of patients habituate and lose treatment efficacy over time, frequently accompanied by a stimulation-induced cerebellar syndrome. The phenomenon termed delayed therapy escape (DTE) is insufficiently understood. Our previous work showed that DTE clinically is pronounced on the non-dominant side and suggested that differential involvement of crossed versus uncrossed DRT (DRTx/DRTu) might play a role in DTE development. METHODS: We retrospectively enrolled right-handed patients under bilateral thalamic DBS >12 months for ET from a cross-sectional study. They were characterized with the Fahn-Tolosa-Marin Tremor Rating Scale (FTMTRS) and Scale for the Assessment and Rating of Ataxia (SARA) scores at different timepoints. Normative fiber tractographic evaluations of crossed and uncrossed cerebellothalamic pathways and volume of activated tissue (VAT) studies together with [18F]Fluorodeoxyglucose positron emission tomography were applied. RESULTS: A total of 29 patients met the inclusion criteria. Favoring DRTu over DRTx in the non-dominant VAT was associated with DTE (R2 = 0.4463, p < 0.01) and ataxia (R2 = 0.2319, p < 0.01). Moreover, increasing VAT size on the right (non-dominant) side was associated at trend level with more asymmetric glucose metabolism shifting towards the right (dominant) dentate nucleus. CONCLUSION: Our results suggest that a disbalanced recruitment of DRTu in the non-dominant VAT induces detrimental stimulation effects on the dominant cerebellar outflow (together with contralateral stimulation) leading to DTE and thus hampering the overall treatment efficacy.

Thalamic segmentation based on diffusion tensor imaging in patients with trigeminal neuralgia.

Classical trigeminal neuralgia (CTN) refers to episodic pain that is strictly confined to the trigeminal distribution area, and the thalamus is an important component of the trigeminal sensory pathway. Probabilistic tracking imaging algorithm was used to identify specific connections between the thalamus and the cortex, in order to identify structural changes in the thalamus of patients with CTN and perform thalamic segmentation. A total of 32 patients with CTN and 32 healthy controls underwent DTI-MRI scanning (3.0 T). Differences in fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD) and mean diffusivity (MD) between the groups were studied. Correlation analysis was performed with clinical course and pain level. Compared to the healthy controls, patients in the CTN group had significantly reduced FA, increased AD, RD and MD in somatosensory subregion of the bilateral thalamus, increased RD in frontal subregion, increased RD and MD in motor subregion. Correlation analysis showed that patient history was positively correlated with pain grading, and that medical history was positively correlated with significantly reduced FA in somatosensory subregion, negatively correlated with increased RD and MD in motor subregion. We used DTI-based probabilistic fiber tracking to discover altered structural connectivity between the thalamus and cerebral cortex in patients with CTN and to obtain a thalamic segmentation atlas, which will help to further understand the pathophysiology of CTN and serve as a future reference for thalamic deep brain stimulation electrode implantation for the treatment of intractable pain.

Neurite orientation dispersion and density imaging quantifies microstructural impairment in the thalamus and its connectivity in amyotrophic lateral sclerosis.

AIMS: To evaluate microstructural impairment in the thalamus and thalamocortical connectivity using neurite orientation dispersion and density imaging (NODDI) in amyotrophic lateral sclerosis (ALS). METHODS: This study included 47 healthy controls and 43 ALS patients, whose structural and diffusion-weighted data were collected. We used state-of-the-art parallel transport tractography to identify thalamocortical pathways in individual spaces. Thalamus was then parcellated into six subregions based on its connectivity pattern with the priori defined cortical (i.e., prefrontal/motor/somatosensory/temporal/posterior-parietal/occipital) regions. For each of the thalamic and cortical subregions and thalamo-cortical tracts, we compared the following NODDI metrics between groups: orientation dispersion index (ODI), neurite density index (NDI), and isotropic volume fraction (ISO). We also used these metrics to conduct receiver operating characteristic curve (ROC) analyses and Spearman correlation. RESULTS: In ALS patients, we found decreased ODI and increased ISO in the thalamic subregion connecting the left motor cortex and other extramotor (e.g., somatosensory and occipital) cortex (Bonferroni-corrected p < 0.05). NDI decreased in the bilateral thalamo-motor and thalamo-somatosensory tracts and in the right thalamo-posterior-parietal and thalamo-occipital tracts (Bonferroni-corrected p < 0.05). NDI reduction in the bilateral thalamo-motor tract (p = 0.017 and 0.009) and left thalamo-somatosensory tract (p = 0.029) was correlated with disease severity. In thalamo-cortical tracts, NDI yielded a higher effect size during between-group comparisons and a greater area under ROC (p < 0.05) compared with conventional diffusion tensor imaging metrics. CONCLUSIONS: Microstructural impairment in the thalamus and thalamocortical connectivity is the hallmark of ALS. NODDI improved the detection of disrupted thalamo-cortical connectivity in ALS.

Arachidonic and docosahexaenoic acid supplementation and brain maturation in preterm infants; a double blind RCT.

BACKGROUND: Arachidonic acid (ARA) and docosahexaenoic acid (DHA) are important structural components of neural cellular membranes and possess anti-inflammatory properties. Very preterm infants are deprived of the enhanced placental supply of these fatty acids, but the benefit of postnatal supplementation on brain development is uncertain. The aim of this study was to test the hypothesis that early enteral supplementation with ARA and DHA in preterm infants improves white matter (WM) microstructure assessed by diffusion-weighted MRI at term equivalent age. METHODS: In this double-blind, randomized controlled trial, infants born before 29 weeks gestational age were allocated to either 100 mg/kg ARA and 50 mg/kg DHA (ARA:DHA group) or medium chain triglycerides (control). Supplements were started on the second day of life and provided until 36 weeks postmenstrual age. The primary outcome was brain maturation assessed by diffusion tensor imaging (DTI) using Tract-Based Spatial Statistics (TBSS) analysis. RESULTS: We included 120 infants (60 per group) in the trial; mean (range) gestational age was 26+3 (22+6 - 28+6) weeks and postmenstrual age at scan was 41+3 (39+1 - 47+0) weeks. Ninety-two infants underwent MRI imaging, and of these, 90 had successful T1/T2 weighted MR images and 74 had DTI data of acceptable quality. TBSS did not show significant differences in mean or axial diffusivity between the groups, but demonstrated significantly higher fractional anisotropy in several large WM tracts in the ARA:DHA group, including corpus callosum, the anterior and posterior limb of the internal capsula, inferior occipitofrontal fasciculus, uncinate fasciculus, and the inferior longitudinal fasciculus. Radial diffusivity was also significantly lower in several of the same WM tracts in the ARA:DHA group. CONCLUSION: This study suggests that supplementation with ARA and DHA at doses matching estimated fetal accretion rates improves WM maturation compared to control treatment, but further studies are needed to ascertain any functional benefit. CLINICAL TRIAL REGISTRATION: www. CLINICALTRIALS: gov; ID:NCT03555019.

Effects of web-based mindfulness training on psychological outcomes, attention, and neuroplasticity.

Mindfulness meditation training (MMT) reliably reduces stress and anxiety while also improving attention. The primary aim of this study was to investigate the relationship between MMT, stress and anxiety reduction, and its impact upon improvements in attention on the behavioral and neuronal levels. As a second aim, we sought to explore any relationship between MMT, attention, and modified states of mind such as flow. 118 healthy, meditation-naïve, participants were either assigned to a 31-day, web-based, MMT or an active control, health training (HT). Participants underwent functional magnetic resonance imaging while performing the attention network test (ANT) to assess functional and behavioural attentional changes, diffusion tensor imaging (DTI) to assess microstructural neuronal changes and completed relevant questionnaires to explore changes in psychological outcomes. Results confirmed a reduction in perceived stress and anxiety levels in the MMT group and significant improvements in the overall reaction time during the ANT, albeit no specific effects on the attentional components were observed. No statistically significant changes were found in the HT group. Interestingly, a significant group-by-time interaction was seen in flow experience. Functional data exhibited an increased activity in the superior frontal gyrus, posterior cingulate cortex, and right hippocampus during the alerting condition of the ANT after the MMT; decreased stress and trait anxiety were significantly correlated with the activation in the right hippocampus, and increased flow was also significantly correlated with all the aforementioned areas. DTI data showed increased fractional anisotropy values in the right uncinate fasciculus indicating white matter microarchitecture improvement between the right hippocampus and frontal areas of the brain. This study, therefore, demonstrates the effectiveness of web-based MMT on overall well-being and attentional performance, while also providing insight into the relationship between psychological outcomes, attention, and neuroplastic changes.

Application Study of Brain Structure and Functional Magnetic Resonance Imaging in Patients with Systemic Lupus Erythematosus and Cognitive Dysfunction.

Objective: This study was aimed to investigate the application value of brain magnetic resonance imaging (MRI) technique, including arterial spin labeling (ASL) and diffusion tensor imaging (DTI) in patients with systemic lupus erythematosus (SLE) and cognitive dysfunction (CDF). Methods: A total of 50 patients with SLE admitted to the hospital from September 2020 to December 2022 were selected and divided into the group with CDF (n = 21) and the group without CDF (n = 29) according to the score of Montreal Cognitive Assessment Scale (MoCA). Additionally, 10 healthy individuals who underwent physical examinations during the same period were recruited as controls. After the conventional MRI, DTI and ASL data of all subjects were collected, statistical parametric mapping software combined with voxel morphology is applied for gray matter volume, white matter and gray matter cerebral blood flow (CBF) analysis among different groups. Results: There is a statistically significant difference in conventional MRI findings between the SLE group and the control group (P < .05). However, There was no significant difference in white matter fractional anisotropy (FA) values between the two groups (P > .05). The apparent diffusion coefficients (ADC) of the right precuneus and the right Brodmann's area 21 and 6 in SLE patients with CDF were significantly higher than SLE patients without CDF (P < .05). In comparison to the non-CDF group, the CDF group exhibited reduced gray matter volume, primarily in the anterior cingulate gyrus, left frontal lobe, and right insula (P < .05). Meanwhile, the white matter and gray matter cerebral blood flow (CBF) of SLE patients with CDF were significantly lower than those without CDF. (P < .05). Correlation analysis showed that the MoCA score was positively associated with the volume of gray matter in the right insula, bilateral frontal lobe, left temporal lobe, and cingulate gyrus (P < .05). Additionally, MoCA score was also found to be positively associated with the CBF of white matter and gray matter (P < .05). Conclusions: Alterations in gray matter volume and CBF in SLE patients are closely associated with combined CDF and can be observed by DTI and ASL techniques.

Assessment of corticospinal tract remodeling based on diffusion tensor imaging in the treatment of motor dysfunction after ischemic stroke by acupuncture: A meta-analysis.

BACKGROUND: To investigate the efficacy of acupuncture in improving motor dysfunction after ischemic stroke (IS) and to investigate the effect of acupuncture on corticospinal tract (CST) remodeling using diffusion tensor imaging. METHODS: Published literature on the effect of acupuncture on CST remodeling after IS using diffusion tensor imaging in the form of randomized controlled trials (RCTs) were systematically retrieved and screened from Cochrane Library, Web of Science, PubMed, Embase, CNKI, CBM, VIP, and Wanfang databases from inception to December 2022. The methodological quality of the included studies was critically and independently evaluated by 2 reviewers using the Cochrane Risk of Bias Assessment Tool for RCTs. The correlated data were extracted using the pre-designed form, and all analyses were performed using Reviewer Manager version 5.4. RESULTS: Eleven eligible RCTs involving 459 patients were eventually included. The combined evidence results showed that the acupuncture group significantly improved patients' National Institute of Health stroke scale, Fugl-Meyer Assessment Scale, and Barthel index compared with conventional medical treatment. The acupuncture group significantly promoted remodeling of the CST, as reflected by an increase in fractional anisotropy (FA) throughout the CST [MD = 0.04, 95% CI (0.02, 0.07), P = .001], and in addition, subgroup analysis showed that the acupuncture group significantly improved FA in the infarct area compared with conventional medical treatment at around 4 weeks [MD = 0.04, 95% CI (0.02, 0.06), P = .0002] and FA of the affected cerebral peduncle [MD = 0.03, 95% CI (0.00, 0.07), P = .02]. Also, compared with conventional medical treatment, the acupuncture group significantly increased average diffusion coefficient of the affected cerebral peduncle [MD = -0.21, 95% CI (-0.28, -0.13), P < .00001]. CONCLUSION: The results of the meta-analysis suggest that acupuncture therapy can improve the clinical manifestations of motor dysfunction in patients after IS and advance a possibly beneficial effect on CST remodeling. However, due to the number and quality of eligible studies, these findings need to be further validated in more standardized, rigorous, high-quality clinical trials.

Aberrant dentato-rubro-thalamic pathway in action tremor but not rest tremor: A multi-modality magnetic resonance imaging study.

AIMS: The purpose of this study was to clarify the dentato-rubro-thalamic (DRT) pathway in action tremor in comparison to normal controls (NC) and disease controls (i.e., rest tremor) by using multi-modality magnetic resonance imaging (MRI). METHODS: This study included 40 essential tremor (ET) patients, 57 Parkinson's disease (PD) patients (29 with rest tremor, 28 without rest tremor), and 41 NC. We used multi-modality MRI to comprehensively assess major nuclei and fiber tracts of the DRT pathway, which included decussating DRT tract (d-DRTT) and non-decussating DRT tract (nd-DRTT), and compared the differences in DRT pathway components between action and rest tremor. RESULTS: Bilateral dentate nucleus (DN) in the ET group had excessive iron deposition compared with the NC group. Compared with the NC group, significantly decreased mean diffusivity and radial diffusivity were observed in the left nd-DRTT in the ET group, which were negatively correlated with tremor severity. No significant difference in each component of the DRT pathway was observed between the PD subgroup or the PD and NC. CONCLUSION: Aberrant changes in the DRT pathway may be specific to action tremor and were indicating that action tremor may be related to pathological overactivation of the DRT pathway.

Free-water correction DTI-based tractography in brain tumor surgery: assessment with functional and electrophysiological mapping of the white matter.

Peritumoral edema prevents fiber tracking from diffusion tensor imaging (DTI). A free-water correction may overcome this drawback, as illustrated in the case of a patient undergoing awake surgery for brain metastasis. The anatomical plausibility and accuracy of tractography with and without free-water correction were assessed with functional mapping and axono-cortical evoked-potentials (ACEPs) as reference methods. The results suggest a potential synergy between corrected DTI-based tractography and ACEPs to reliably identify and preserve white matter tracts during brain tumor surgery.

Dissociable Contributions of Thalamic-Subregions to Cognitive Impairment in Small Vessel Disease.

BACKGROUND: Structural network damage is a potentially important mechanism by which cerebral small vessel disease (SVD) can cause cognitive impairment. As a central hub of the structural network, the role of thalamus in SVD-related cognitive impairments remains unclear. We aimed to determine the associations between the structural alterations of thalamic subregions and cognitive impairments in SVD. METHODS: In this cross-sectional study, 205 SVD participants without thalamic lacunes from the third follow-up (2020) of the prospective RUN DMC study (Radboud University Nijmegen Diffusion Tensor and Magnetic Resonance Cohort), which was initiated in 2006, Nijmegen, were included. Cognitive functions included processing speed, executive function, and memory. Probabilistic tractography was performed from thalamus to 6 cortical regions, followed by connectivity-based thalamic segmentation to assess each thalamic subregion volume and connectivity (measured by mean diffusivity [MD] of the connecting white matter tracts) with the cortex. Least absolute shrinkage and selection operator regression analysis was conducted to identify the volumes or connectivity of the total thalamus and 6 thalamic subregions that have the strongest association with cognitive performance. Linear regression and mediation analyses were performed to test the association of least absolute shrinkage and selection operator-selected thalamic subregion volume or MD with cognitive performance, while adjusting for age and education. RESULTS: We found that higher MD of the thalamic-motor tract was associated with worse processing speed (ß=-0.27; P<0.001), higher MD of the thalamic-frontal tract was associated with worse executive function (ß=-0.24; P=0.001), and memory (ß=-0.28; P<0.001), respectively. The mediation analysis showed that MD of thalamocortical tracts mediated the association between corresponding thalamic subregion volumes and the cognitive performances in 3 domains. CONCLUSIONS: Our results suggest that the structural alterations of thalamus are linked to cognitive impairment in SVD, largely depending on the damage pattern of the white matter tracts connecting specific thalamic subregions and cortical regions.

[Efficacy and mechanism of scalp acupuncture for spastic cerebral palsy].

OBJECTIVE: To observe the clinical efficacy of scalp acupuncture for spastic cerebral palsy (CP), and to explore its possible mechanism based on brain white matter fiber bundles, nerve growth related proteins and inflammatory cytokines. METHODS: A total of 90 children with spastic CP were randomly divided into a scalp acupuncture group and a sham scalp acupuncture group, 45 cases in each group. The children in the two groups were treated with conventional comprehensive rehabilitation treatment. The children in the scalp acupuncture group were treated with scalp acupuncture at the parietal temporal anterior oblique line, parietal temporal posterior oblique line on the affected side, and parietal midline. The children in the sham scalp acupuncture group were treated with scalp acupuncture at 1 cun next to the above point lines. The needles were kept for 30 min, once a day, 5 days a week, for 12 weeks. Before and after treatment, the diffusion tensor imaging (DTI) indexes of magnetic resonance (FA values of corticospinal tract [CST], anterior limb of internal capsule [ICAL], posterior limb of internal capsule [ICPL], genu of internal capsule [ICGL], genu of corpus callosum [GCC], body of corpus callosum [BCC] and splenium of corpus callosum [SCC]), serum levels of nerve growth related proteins (neuron-specific enolase [NSE], glial fibrillary acidic protein [GFAP], myelin basic protein [MBP], ubiquitin carboxy terminal hydrolase-L1 [UCH-L1]) and inflammatory cytokines (interleukin 33 [IL-33], tumor necrosis factor α [TNF-α]), cerebral hemodynamic indexes (mean blood flow velocity [Vm], systolic peak flow velocity [Vs] and resistance index [RI], pulsatility index [PI] of cerebral artery), surface electromyography (SEMG) signal indexes (root mean square [RMS] values of rectus femoris, hamstring muscles, gastrocnemius muscles, tibialis anterior muscles), gross motor function measure-88 (GMFM-88) score, modified Ashworth scale (MAS) score, ability of daily living (ADL) score were observed in the two groups. The clinical effect of the two groups was compared. RESULTS: After treatment, the FA value of each fiber bundle, Vm, Vs, GMFM-88 scores and ADL scores in the two groups were higher than those before treatment (P<0.05), and the above indexes in the scalp acupuncture group were higher than those in the sham scalp acupuncture group (P<0.05). After treatment, the serum levels of NSE, GFAP, MBP, UCH-L1, IL-33, TNF-α as well as RI, PI, MAS scores and RMS values of each muscle were lower than those before treatment (P<0.05), and the above indexes in the scalp acupuncture group were lower than those in the sham scalp acupuncture group (P<0.05). The total effective rate was 95.6% (43/45) in the scalp acupuncture group, which was higher than 82.2% (37/45) in the sham scalp acupuncture group (P<0.05). CONCLUSION: Scalp acupuncture could effectively treat spastic CP, improve the cerebral hemodynamics and gross motor function, reduce muscle tension and spasticity, and improve the ability of daily life. The mechanism may be related to repairing the white matter fiber bundles and regulating the levels of nerve growth related proteins and inflammatory cytokines.

Analysis of changes in brain morphological structure of taekwondo athletes by diffusion tensor imaging.

OBJECTIVE: Taekwondo, which is the most preferred sport among the martial arts, is known to improve individuals physically, spiritually and mentally. The aim of this study is to reveal the effect of teakwondo sport on the brain and brain structures. DESIGN;: 30 taekwondo athletes and 15 control groups were included in this study. Diffusion tensor MR images of each participant were taken. The information was obtained by the self-declaration of the athletes, whether they were sports years, amateur or elite. METHOD: Total brain volume and volumes of white matter, gray matter, frontal lobe, precentral gyrus, corticospinal tract, basal nuclei, postcentral gyrus, hippocampus and amigdala and the ratio of these volumes to total brain volume were evaluated statistically between the groups using MriCloud software and ROIEditor program. RESULTS: An increase in total brain volume, gray matter, frontal lobe and precentral gyrus volume in athletes was associated with taekwondo training. When the ratio of brain parts to total brain volume was examined, it was determined that there was a difference in the ratio of gray matter, white matter volumes in amateur athletes, right frontal lobe, left corticospinal tract, right postcentral gyrus volumes in elite athletes, and left postcentral gyrus volumes of both athletes compared to sedentary individuals. CONCLUSIONS: The increase in the volume of gray matter, frontal lobe, postcentral gyrus and corticospinal tract together with the brain volume shows that taekwondo exercise contributes to physical, spiritual and mental development.

The effect of mindfulness-based intervention on neurobehavioural functioning and its association with white-matter microstructural changes in preterm young adolescents.

Very preterm (VPT) young adolescents are at high risk of executive, behavioural and socio-emotional difficulties. Previous research has shown significant evidence of the benefits of mindfulness-based intervention (MBI) on these abilities. This study aims to assess the association between the effects of MBI on neurobehavioral functioning and changes in white-matter microstructure in VPT young adolescents who completed an 8-week MBI program. Neurobehavioural assessments (i.e., neuropsychological testing, parents- and self-reported questionnaires) and multi-shell diffusion MRI were performed before and after MBI in 32 VPT young adolescents. Combined diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) measures were extracted on well-defined white matter tracts (TractSeg). A multivariate data-driven approach (partial least squares correlation) was used to explore associations between MBI-related changes on neurobehavioural measures and microstructural changes. The results showed an enhancement of global executive functioning using parent-reported questionnaire after MBI that was associated with a general pattern of increase in fractional anisotropy (FA) and decrease in axonal dispersion (ODI) in white-matter tracts involved in executive processes. Young VPT adolescents with lower gestational age at birth showed the greatest gain in white-matter microstructural changes after MBI.

Thalamic Segmentation and Neural Activation Modeling Based on Individual Tissue Microstructure in Deep Brain Stimulation for Essential Tremor.

OBJECTIVE: Thalamic deep brain stimulation (DBS) is the primary surgical therapy for essential tremor (ET). Thalamic DBS traditionally uses an atlas-based targeting approach, which, although nominally accurate, may obscure individual anatomic differences from population norms. The objective of this study was to compare this traditional atlas-based approach with a novel quantitative modeling methodology grounded in individual tissue microstructure (N-of-1 approach). MATERIALS AND METHODS: The N-of-1 approach uses individual patient diffusion tensor imaging (DTI) data to perform thalamic segmentation and volume of tissue activation (VTA) modeling. For each patient, the thalamus was individually segmented into 13 nuclei using DTI-based k-means clustering. DBS-induced VTAs associated with tremor suppression and side effects were then computed for each patient with finite-element electric-field models incorporating DTI microstructural data. Results from N-of-1 and traditional atlas-based modeling were compared for a large cohort of patients with ET treated with thalamic DBS. RESULTS: The size and shape of individual N-of-1 thalamic nuclei and VTAs varied considerably across patients (N = 22). For both methods, tremor-improving therapeutic VTAs showed similar overlap with motor thalamic nuclei and greater motor than sensory nucleus overlap. For VTAs producing undesirable sustained paresthesia, 94% of VTAs overlapped with N-of-1 sensory thalamus estimates, whereas 74% of atlas-based segmentations overlapped. For VTAs producing dysarthria/motor contraction, the N-of-1 approach predicted greater spread beyond the thalamus into the internal capsule and adjacent structures than the atlas-based method. CONCLUSIONS: Thalamic segmentation and VTA modeling based on individual tissue microstructure explain therapeutic stimulation equally well and side effects better than a traditional atlas-based method in DBS for ET. The N-of-1 approach may be useful in DBS targeting and programming, particularly when patient neuroanatomy deviates from population norms.

Evidence of An Association Between Cerebral Blood Flow and Microstructural Integrity in Normative Aging Using a Holistic MRI Approach.

BACKGROUND: Cerebral tissue integrity decline and cerebral blood flow (CBF) alteration are major aspects of motor and cognitive dysfunctions and neurodegeneration. However, little is known about the association between blood flow and brain microstructural integrity, especially in normal aging. PURPOSE: To assess the association between CBF and cerebral microstructural integrity. STUDY TYPE: Cross sectional. POPULATION: A total of 94 cognitively unimpaired adults (mean age 50.7 years, age range between 22 and 88 years, 56 Men). FIELD STRENGTH/SEQUENCE: A 3 T; pseudo-continuous arterial spin labeling (pCASL), diffusion tensor imaging (DTI), Bayesian Monte Carlo analysis of multicomponent driven equilibrium steady-state observation of T1 and T2 (BMC-mcDESPOT). ASSESSMENT: Lobar associations between CBF derived from pCASL, and longitudinal relaxation rate (R1 ), transverse relaxation rate (R2 ) and myelin water fraction (MWF) derived from BMC-mcDESPOT, or radial diffusivity (RD), axial diffusivity (AxD), mean diffusivity (MD) and fractional anisotropy (FA) derived from DTI were assessed. STATISTICAL TESTS: Multiple linear regression models were used using the mean region of interest (ROI) values for MWF, R1 , R2 , FA, MD, RD, or AxD as the dependent variable and CBF, age, age2 , and sex as the independent variables. A two-sided P value of <0.05 defined statistical significance. RESULTS: R1 , R2 , MWF, FA, MD, RD, and AxD parameters were associated with CBF in most of the cerebral regions evaluated. Specifically, higher CBF values were significantly associated with higher FA, MWF, R1 and R2 , or lower MD, RD and AxD values. DATA CONCLUSION: These findings suggest that cerebral tissue microstructure may be impacted by global brain perfusion, adding further evidence to the intimate relationship between cerebral blood supply and cerebral tissue integrity. EVIDENCE LEVEL: 4 TECHNICAL EFFICACY: Stage 4.

Mediation of Tremor Control by the Decussating and Nondecussating Part of the Dentato-Rubro-Thalamic Tract in Deep Brain Stimulation in Essential Tremor: Which Part Should Be Stimulated?

OBJECTIVES: The dentato-rubro-thalamic tract (DRTT) has been found to play a major role in the mechanisms of tremor alleviation by deep brain stimulation (DBS) in essential tremor (ET). Still, the influence of the two different parts of the DRTT, consisting of crossing and nondecussating fibers, is not yet clear with respect to tremor reduction. The aim of this study was to assess the influence of the crossing and the nondecussating part of the DRTT on tremor control in ET. MATERIALS AND METHODS: We investigated 80 electrode contacts in ten patients with ET who received bilateral DBS of the Nucleus ventralis intermedius of the thalamus (VIM). Preoperatively and with patients under general anesthesia, 3T magnetic resonance imaging scans were performed, including Diffusion Tensor Imaging scans with 64 gradient directions. We calculated the course of the two parts of the DRTT based on a workflow for probabilistic fiber tracking including protocols for correction of susceptibility- and eddy current-induced distortions. Distances of electrode contacts were correlated with clinical data from neurologic single pole testing. RESULTS: Voltage- and current-steered systems were analyzed separately. Regarding postural tremor, effective contacts showed significantly lower distances to both parts of the DRTT (crossing p < 0.001, nondecussating p < 0.05) in voltage-steered systems. Regarding intentional tremor, significant results were only found for the crossing part (p < 0.01). Regarding both tremor types, effective contacts were closer to the crossing part, unlike less effective contacts. Nonlinear regression analyses using a logistic model showed higher coefficients for the crossing part of the DRTT. Multivariate regression models including distances to both parts of the DRTT showed a significant influence of only the crossing part. Analysis of current-steered systems showed unstable data, probably because of the small number of analyzed patients. CONCLUSIONS: Our data suggest an involvement of both parts of the DRTT in tremor reduction, indicating mediation of DBS effects by both fiber bundles, although the crossing part showed stronger correlations with good clinical responses. Nevertheless, special attention should be paid to methodologic aspects when using probabilistic tractography for patient-specific targeting to avoid uncertain and inaccurate results.

Efficacy and mechanism of scalp acupuncture for spastic cerebral palsy / 中国针灸

OBJECTIVE@#To observe the clinical efficacy of scalp acupuncture for spastic cerebral palsy (CP), and to explore its possible mechanism based on brain white matter fiber bundles, nerve growth related proteins and inflammatory cytokines.@*METHODS@#A total of 90 children with spastic CP were randomly divided into a scalp acupuncture group and a sham scalp acupuncture group, 45 cases in each group. The children in the two groups were treated with conventional comprehensive rehabilitation treatment. The children in the scalp acupuncture group were treated with scalp acupuncture at the parietal temporal anterior oblique line, parietal temporal posterior oblique line on the affected side, and parietal midline. The children in the sham scalp acupuncture group were treated with scalp acupuncture at 1 cun next to the above point lines. The needles were kept for 30 min, once a day, 5 days a week, for 12 weeks. Before and after treatment, the diffusion tensor imaging (DTI) indexes of magnetic resonance (FA values of corticospinal tract [CST], anterior limb of internal capsule [ICAL], posterior limb of internal capsule [ICPL], genu of internal capsule [ICGL], genu of corpus callosum [GCC], body of corpus callosum [BCC] and splenium of corpus callosum [SCC]), serum levels of nerve growth related proteins (neuron-specific enolase [NSE], glial fibrillary acidic protein [GFAP], myelin basic protein [MBP], ubiquitin carboxy terminal hydrolase-L1 [UCH-L1]) and inflammatory cytokines (interleukin 33 [IL-33], tumor necrosis factor α [TNF-α]), cerebral hemodynamic indexes (mean blood flow velocity [Vm], systolic peak flow velocity [Vs] and resistance index [RI], pulsatility index [PI] of cerebral artery), surface electromyography (SEMG) signal indexes (root mean square [RMS] values of rectus femoris, hamstring muscles, gastrocnemius muscles, tibialis anterior muscles), gross motor function measure-88 (GMFM-88) score, modified Ashworth scale (MAS) score, ability of daily living (ADL) score were observed in the two groups. The clinical effect of the two groups was compared.@*RESULTS@#After treatment, the FA value of each fiber bundle, Vm, Vs, GMFM-88 scores and ADL scores in the two groups were higher than those before treatment (P<0.05), and the above indexes in the scalp acupuncture group were higher than those in the sham scalp acupuncture group (P<0.05). After treatment, the serum levels of NSE, GFAP, MBP, UCH-L1, IL-33, TNF-α as well as RI, PI, MAS scores and RMS values of each muscle were lower than those before treatment (P<0.05), and the above indexes in the scalp acupuncture group were lower than those in the sham scalp acupuncture group (P<0.05). The total effective rate was 95.6% (43/45) in the scalp acupuncture group, which was higher than 82.2% (37/45) in the sham scalp acupuncture group (P<0.05).@*CONCLUSION@#Scalp acupuncture could effectively treat spastic CP, improve the cerebral hemodynamics and gross motor function, reduce muscle tension and spasticity, and improve the ability of daily life. The mechanism may be related to repairing the white matter fiber bundles and regulating the levels of nerve growth related proteins and inflammatory cytokines.

A Hypothalamic Mechanism Regulates the Duration of a Migraine Attack: Insights from Microstructural and Temporal Complexity of Cortical Functional Networks Analysis.

The role of the hypothalamus and the limbic system at the onset of a migraine attack has recently received significant interest. We analyzed diffusion tensor imaging (DTI) parameters of the entire hypothalamus and its subregions in 15 patients during a spontaneous migraine attack and in 20 control subjects. We also estimated the non-linear measure resting-state functional MRI BOLD signal's complexity using Higuchi fractal dimension (FD) and correlated DTI/fMRI findings with patients' clinical characteristics. In comparison with healthy controls, patients had significantly altered diffusivity metrics within the hypothalamus, mainly in posterior ROIs, and higher FD values in the salience network (SN). We observed a positive correlation of the hypothalamic axial diffusivity with migraine severity and FD of SN. DTI metrics of bilateral anterior hypothalamus positively correlated with the mean attack duration. Our results show plastic structural changes in the hypothalamus related to the attacks severity and the functional connectivity of the SN involved in the multidimensional neurocognitive processing of pain. Plastic changes to the hypothalamus may play a role in modulating the duration of the attack.

Effects of hyperbaric oxygen therapy on functional and structural connectivity in post-COVID-19 condition patients: A randomized, sham-controlled trial.

INTRODUCTION: Post-COVID-19 condition refers to a range of persisting physical, neurocognitive, and neuropsychological symptoms after SARS-CoV-2 infection. Abnormalities in brain connectivity were found in recovered patients compared to non-infected controls. This study aims to evaluate the effect of hyperbaric oxygen therapy (HBOT) on brain connectivity in post-COVID-19 patients. METHODS: In this randomized, sham-controlled, double-blind trial, 73 patients were randomized to receive 40 daily sessions of HBOT (n = 37) or sham treatment (n = 36). We examined pre- and post-treatment resting-state brain functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) scans to evaluate functional and structural connectivity changes, which were correlated to cognitive and psychological distress measures. RESULTS: The ROI-to-ROI analysis revealed decreased internetwork connectivity in the HBOT group which was negatively correlated to improvements in attention and executive function scores (p < 0.001). Significant group-by-time interactions were demonstrated in the right hippocampal resting state function connectivity (rsFC) in the medial prefrontal cortex (PFWE = 0.002). Seed-to-voxel analysis also revealed a negative correlation in the brief symptom inventory (BSI-18) score and in the rsFC between the amygdala seed, the angular gyrus, and the primary sensory motor area (PFWE = 0.012, 0.002). Positive correlations were found between the BSI-18 score and the left insular cortex seed and FPN (angular gyrus) (PFWE < 0.0001). Tractography based structural connectivity analysis showed a significant group-by-time interaction in the fractional anisotropy (FA) of left amygdala tracts (F = 7.81, P = 0.007). The efficacy measure had significant group-by-time interactions (F = 5.98, p = 0.017) in the amygdala circuit. CONCLUSIONS: This study indicates that HBOT improves disruptions in white matter tracts and alters the functional connectivity organization of neural pathways attributed to cognitive and emotional recovery in post-COVID-19 patients. This study also highlights the potential of structural and functional connectivity analysis as a promising treatment response monitoring tool.

Presurgical diffusion metrics of the thalamus and thalamic nuclei in postoperative delirium: A prospective two-centre cohort study in older patients.

BACKGROUND: The thalamus seems to be important in the development of postoperative delirium (POD) as previously revealed by volumetric and diffusion magnetic resonance imaging. In this observational cohort study, we aimed to further investigate the impact of the microstructural integrity of the thalamus and thalamic nuclei on the incidence of POD by applying diffusion kurtosis imaging (DKI). METHODS: Older patients without dementia (≥65 years) who were scheduled for major elective surgery received preoperative DKI at two study centres. The DKI metrics fractional anisotropy (FA), mean diffusivity (MD), mean kurtosis (MK) and free water (FW) were calculated for the thalamus and - as secondary outcome - for eight predefined thalamic nuclei and regions. Low FA and MK and, conversely, high MD and FW, indicate aspects of microstructural abnormality. To assess patients' POD status, the Nursing Delirium Screening Scale (Nu-DESC), Richmond Agitation Sedation Scale (RASS), Confusion Assessment Method (CAM) and Confusion Assessment Method for the Intensive Care Unit score (CAM-ICU) and chart review were applied twice a day after surgery for the duration of seven days or until discharge. For each metric and each nucleus, logistic regression was performed to assess the risk of POD. RESULTS: This analysis included the diffusion scans of 325 patients, of whom 53 (16.3 %) developed POD. Independently of age, sex and study centre, thalamic MD was statistically significantly associated with POD [OR 1.65 per SD increment (95 %CI 1.17 - 2.34) p = 0.004]. FA (p = 0.84), MK (p = 0.41) and FW (p = 0.06) were not significantly associated with POD in the examined sample. Exploration of thalamic nuclei also indicated that only the MD in certain areas of the thalamus was associated with POD. MD was increased in bilateral hemispheres, pulvinar nuclei, mediodorsal nuclei and the left anterior nucleus. CONCLUSIONS: Microstructural abnormalities of the thalamus and thalamic nuclei, as reflected by increased MD, appear to predispose to POD. These findings affirm the thalamus as a region of interest in POD research.