Search Results Heading

MBRLSearchResults

mbrl.module.common.modules.added.book.to.shelf
Title added to your shelf!
View what I already have on My Shelf.
Oops! Something went wrong.
Oops! Something went wrong.
While trying to add the title to your shelf something went wrong :( Kindly try again later!
Are you sure you want to remove the book from the shelf?
Oops! Something went wrong.
Oops! Something went wrong.
While trying to remove the title from your shelf something went wrong :( Kindly try again later!
    Done
    Filters
    Reset
  • Discipline
      Discipline
      Clear All
      Discipline
  • Is Peer Reviewed
      Is Peer Reviewed
      Clear All
      Is Peer Reviewed
  • Item Type
      Item Type
      Clear All
      Item Type
  • Subject
      Subject
      Clear All
      Subject
  • Year
      Year
      Clear All
      From:
      -
      To:
  • More Filters
      More Filters
      Clear All
      More Filters
      Source
    • Language
5,102 result(s) for "grey matter"
Sort by:
Effects of Silexan on the Serotonin-1A Receptor and Microstructure of the Human Brain: A Randomized, Placebo-Controlled, Double-Blind, Cross-Over Study with Molecular and Structural Neuroimaging
Background:Recently, Silexan, a patented active substance comprised of an essential oil produced from Lavandula angustifolia flowers, has been authorized in Germany as a medicinal product for the treatment of states of restlessness related to anxious mood. Its efficacy has been shown in several forms of anxiety disorders. Findings from preclinical and clinical studies attribute a major role to the serotonin-1A receptor in the pathogenesis and treatment of anxiety.Methods:To elucidate the effect of Silexan on serotonin-1A receptor binding, 17 healthy men underwent 2 positron emission tomography measurements using the radioligand [carbonyl-11C]WAY-100635 following the daily intake of 160mg Silexan or placebo for a minimum of 8 weeks (randomized, double-blind, cross-over design). Additionally, structural magnetic resonance imaging and voxel-based morphometry analysis was performed to determine potential effects on gray matter microstructure.Results:Serotonin-1A receptor binding potential was shown to be significantly reduced following the intake of Silexan compared with placebo in 2 large clusters encompassing the temporal gyrus, the fusiform gyrus and the hippocampus on one hand as well as the insula and anterior cingulate cortex on the other hand. No effects of Silexan on gray matter volume could be detected in this investigation.Conclusion:This positron emission tomography study proposes an involvement of the serotonin-1A receptor in the anxiolytic effects of Silexan.The study was registered in the International Standard Randomized Controlled Trial Number Register as ISRCTN30885829 (http://www.controlled-trials.com/isrctn/).
Cerebral blood flow and arterial transit time responses to exercise training in older adults
•Home-based high-intensity interval training increases cardiorespiratory fitness in older adults.•High cardiorespiratory fitness gains were associated with cerebral blood flow reductions.•Exercise training did not affect arterial transit time or cognitive function in older adults. Brain vascular health worsens with age, as is made evident by resting grey matter cerebral blood flow (CBFGM) reductions and lengthening arterial transit time (ATTGM). Exercise training can improve aspects of brain health in older adults, yet its effects on CBFGM and ATTGM remain unclear. This randomised controlled trial assessed responses of CBFGM and ATTGM to a 26 week exercise intervention in 65 healthy older adults (control: n = 33, exercise: n = 32, aged 60–81 years), including whether changes in CBFGM or ATTGM were associated with changes in cognitive functions. Multiple-delay pseudo-continuous arterial spin labelling data were used to estimate resting global and regional CBFGM and ATTGM. Results showed no between-group differences in CBFGM or ATTGM following the intervention. However, exercise participants with the greatest cardiorespiratory gains (n = 17; ∆V̇O2peak >2 mL/kg/min) experienced global CBFGM reductions (-4.0 [-7.3, -0.8] mL/100 g/min). Cognitive functions did not change in either group and changes were not associated with changes in CBFGM or ATTGM. Our findings indicate that exercise training in older adults may induce global CBFGM reductions when high cardiorespiratory fitness gains are induced, but this does not appear to affect cognitive functions.
Menopause impacts human brain structure, connectivity, energy metabolism, and amyloid-beta deposition
All women undergo the menopause transition (MT), a neuro-endocrinological process that impacts aging trajectories of multiple organ systems including brain. The MT occurs over time and is characterized by clinically defined stages with specific neurological symptoms. Yet, little is known of how this process impacts the human brain. This multi-modality neuroimaging study indicates substantial differences in brain structure, connectivity, and energy metabolism across MT stages (pre-menopause, peri-menopause, and post-menopause). These effects involved brain regions subserving higher-order cognitive processes and were specific to menopausal endocrine aging rather than chronological aging, as determined by comparison to age-matched males. Brain biomarkers largely stabilized post-menopause, and gray matter volume (GMV) recovered in key brain regions for cognitive aging. Notably, GMV recovery and in vivo brain mitochondria ATP production correlated with preservation of cognitive performance post-menopause, suggesting adaptive compensatory processes. In parallel to the adaptive process, amyloid-β deposition was more pronounced in peri-menopausal and post-menopausal women carrying apolipoprotein E-4 (APOE-4) genotype, the major genetic risk factor for late-onset Alzheimer’s disease, relative to genotype-matched males. These data show that human menopause is a dynamic neurological transition that significantly impacts brain structure, connectivity, and metabolic profile during midlife endocrine aging of the female brain.
The SIGMA rat brain templates and atlases for multimodal MRI data analysis and visualization
Preclinical imaging studies offer a unique access to the rat brain, allowing investigations that go beyond what is possible in human studies. Unfortunately, these techniques still suffer from a lack of dedicated and standardized neuroimaging tools, namely brain templates and descriptive atlases. Here, we present two rat brain MRI templates and their associated gray matter, white matter and cerebrospinal fluid probability maps, generated from ex vivo T 2 * -weighted images (90 µm isotropic resolution) and in vivo T 2 -weighted images (150 µm isotropic resolution). In association with these templates, we also provide both anatomical and functional 3D brain atlases, respectively derived from the merging of the Waxholm and Tohoku atlases, and analysis of resting-state functional MRI data. Finally, we propose a complete set of preclinical MRI reference resources, compatible with common neuroimaging software, for the investigation of rat brain structures and functions. Magnetic resonance imaging (MRI) is widely used to study the rat brain. Here, the authors provide standardized MRI brain templates and descriptive atlases for the rat, incorporating both structural and functional MRI data, along with associated resources.
Meningeal inflammation changes the balance of TNF signalling in cortical grey matter in multiple sclerosis
Background Recent studies of cortical pathology in secondary progressive multiple sclerosis have shown that a more severe clinical course and the presence of extended subpial grey matter lesions with significant neuronal/glial loss and microglial activation are associated with meningeal inflammation, including the presence of lymphoid-like structures in the subarachnoid space in a proportion of cases. Methods To investigate the molecular consequences of pro-inflammatory and cytotoxic molecules diffusing from the meninges into the underlying grey matter, we carried out gene expression profiling analysis of the motor cortex from 20 post-mortem multiple sclerosis brains with and without substantial meningeal inflammation and 10 non-neurological controls. Results Gene expression profiling of grey matter lesions and normal appearing grey matter not only confirmed the substantial pathological cell changes, which were greatest in multiple sclerosis cases with increased meningeal inflammation, but also demonstrated the upregulation of multiple genes/pathways associated with the inflammatory response. In particular, genes involved in tumour necrosis factor (TNF) signalling were significantly deregulated in MS cases compared with controls. Increased meningeal inflammation was found to be associated with a shift in the balance of TNF signalling away from TNFR1/TNFR2 and NFkB-mediated anti-apoptotic pathways towards TNFR1- and RIPK3-mediated pro-apoptotic/pro-necroptotic signalling in the grey matter, which was confirmed by RT-PCR analysis. TNFR1 was found expressed preferentially on neurons and oligodendrocytes in MS cortical grey matter, whereas TNFR2 was predominantly expressed by astrocytes and microglia. Conclusions We suggest that the inflammatory milieu generated in the subarachnoid space of the multiple sclerosis meninges by infiltrating immune cells leads to increased demyelinating and neurodegenerative pathology in the underlying grey matter due to changes in the balance of TNF signalling.
Phagocyte-mediated synapse removal in cortical neuroinflammation is promoted by local calcium accumulation
Cortical pathology contributes to chronic cognitive impairment of patients suffering from the neuroinflammatory disease multiple sclerosis (MS). How such gray matter inflammation affects neuronal structure and function is not well understood. In the present study, we use functional and structural in vivo imaging in a mouse model of cortical MS to demonstrate that bouts of cortical inflammation disrupt cortical circuit activity coincident with a widespread, but transient, loss of dendritic spines. Spines destined for removal show local calcium accumulations and are subsequently removed by invading macrophages or activated microglia. Targeting phagocyte activation with a new antagonist of the colony-stimulating factor 1 receptor prevents cortical synapse loss. Overall, our study identifies synapse loss as a key pathological feature of inflammatory gray matter lesions that is amenable to immunomodulatory therapy. Synapse loss is prominent in the cortex in multiple sclerosis (MS). In a cortical MS model, Jafari et al. show that phagocytes remove synapses by engulfment, which is triggered by local calcium accumulations and prevented by blocking colony-stimulating factor 1 signaling.
Neurotoxicity in breast cancer survivors ≥10 years post-treatment is dependent on treatment type
Adjuvant chemotherapy (CT) for breast cancer (BC) is associated with very late side-effects on brain function and structure. However, little is known about neurotoxicity of specific treatment regimens. To compare neurotoxicity profiles after different treatment strategies, we used neurocognitive testing and multimodality MRI in BC survivors randomized to high-dose (HI), conventional-dose (CON-) CT or radiotherapy (RT) only and a healthy control (HC) group. BC survivors who received CON-CT ( n  = 20) and HC ( n  = 20) were assessed using a neurocognitive test battery and multimodality MRI including 3D-T1, Diffusion Tensor Imaging (DTI) and 1H-MR spectroscopy (1H-MRS) to measure various aspects of cerebral white (WM) and gray matter (GM). Data were compared to previously assessed groups of BC survivors who received HI-CT ( n  = 17) and RT-only ( n  = 15). Testing took place on average 11.5 years post-CT. 3D-T1 showed focal GM volume reductions both for HI-CT and CON-CT compared to RT-only ( p  < .004). DTI-derived mean diffusivity and 1H-MRS derived N-acetyl aspartate showed WM injury specific to HI-CT but not CON-CT ( p  < .05). Residual effects were revealed in the RT-only group compared to HC on MRI and neurocognitive measurements ( p  < .05). Ten years after adjuvant CT for BC lower cerebral GM volume was found in HI as well as CON-CT BC survivors whereas injury to WM is restricted to HI-CT. This might indicate that WM brain changes after BC treatment may show more pronounced (partial) recovery than GM. Furthermore, our results suggest residual neurotoxicity in the RT-only group, which warrants further investigation.
Reduced tactile acuity in chronic low back pain is linked with structural neuroplasticity in primary somatosensory cortex and is modulated by acupuncture therapy
Prior studies have shown that patients suffering from chronic Low Back Pain (cLBP) have impaired somatosensory processing including reduced tactile acuity, i.e. reduced ability to resolve fine spatial details with the perception of touch. The central mechanism(s) underlying reduced tactile acuity are unknown but may include changes in specific brain circuitries (e.g. neuroplasticity in the primary somatosensory cortex, S1). Furthermore, little is known about the linkage between changes in tactile acuity and the amelioration of cLBP by somatically-directed therapeutic interventions, such as acupuncture. In this longitudinal neuroimaging study, we evaluated healthy control adults (HC, N ​= ​50) and a large sample of cLBP patients (N ​= ​102) with structural brain imaging (T1-weighted MRI for Voxel-Based Morphometry, VBM; Diffusion Tensor Imaging, DTI) and tactile acuity testing using two-point discrimination threshold (2PDT) over the lower back (site of pain) and finger (control) locations. Patients were evaluated at baseline and following a 4-week course of acupuncture, with patients randomized to either verum acupuncture, two different forms of sham acupuncture (designed with or without somatosensory afference), or no-intervention usual care control. At baseline, cLBP patients demonstrated reduced acuity (greater 2PDT, P ​= ​0.01) over the low back, but not finger (P ​= ​0.29) locations compared to HC, suggesting that chronic pain affects tactile acuity specifically at body regions encoding the experience of clinical pain. At baseline, Gray Matter Volume (GMV) was elevated and Fractional Anisotropy (FA) was reduced, respectively, in the S1-back region of cLBP patients compared to controls (P ​< ​0.05). GMV in cLBP correlated with greater 2PDT-back scores (ρ ​= ​0.27, P ​= ​0.02). Following verum acupuncture, tactile acuity over the back was improved (reduced 2PDT) and greater improvements were associated with reduced S1-back GMV (ρ ​= ​0.52, P ​= ​0.03) and increased S1-back adjacent white matter FA (ρ ​= ​−0.56, P ​= ​0.01). These associations were not seen for non-verum control interventions. Thus, S1 neuroplasticity in cLBP is linked with deficits in tactile acuity and, following acupuncture therapy, may represent early mechanistic changes in somatosensory processing that track with improved tactile acuity.
Deficits in ascending and descending pain modulation pathways in patients with postherpetic neuralgia
•PHN patients had increased state and trait anxiety and depression than controls.•PHN patients had smaller gray matter volumes of thalamus and amygdala than controls.•The thalamus volume was negatively correlated with pain intensity in PHN patients.•Abnormal FC patterns within pain modulation pathways were observed in PHN patients.•The effect of depression on pain was mediated by the PAG-SI FC in PHN patients. Postherpetic Neuralgia (PHN), develops after the resolution of the herpes zoster mucocutaneous eruption, is a debilitating chronic pain. However, there is a lack of knowledge regarding the underlying mechanisms associated with ascending and descending pain modulations in PHN patients. Here, we combined psychophysics with structural and functional magnetic resonance imaging (MRI) techniques to investigate the brain alternations in PHN patients. Psychophysical tests showed that compared with healthy controls, PHN patients had increased state and trait anxiety and depression. Structural MRI data indicated that PHN patients had significantly smaller gray matter volumes of the thalamus and amygdala than healthy controls, and the thalamus volume was negatively correlated with pain intensity (assessed using the Short-form of the McGill pain questionnaire) in PHN patients. When the thalamus and periaqueductal gray matter (PAG) were used as the seeds, resting-state functional MRI data revealed abnormal patterns of functional connectivity within ascending and descending pain pathways in PHN patients, e.g., increased functional connectivity between the thalamus and somatosensory cortices and decreased functional connectivity between the PAG and frontal cortices. In addition, subjective ratings of both Present Pain Index (PPI) and Beck-Depression Inventory (BDI) were negatively correlated with the strength of functional connectivity between the PAG and primary somatosensory cortex (SI), and importantly, the effect of BDI on PPI was mediated by the PAG-SI functional connectivity. Overall, our results provided evidence suggesting deficits in ascending and descending pain modulation pathways, which were highly associated with the intensity of chronic pain and its emotional comorbidities in PHN patients. Therefore, our study deepened our understanding of the pathogenesis of PHN, which would be helpful in determining the optimized treatment for the patients.
Global and regional annual brain volume loss rates in physiological aging
The objective is to estimate average global and regional percentage brain volume loss per year (BVL/year) of the physiologically ageing brain. Two independent, cross-sectional single scanner cohorts of healthy subjects were included. The first cohort ( n  = 248) was acquired at the Medical Prevention Center (MPCH) in Hamburg, Germany. The second cohort ( n  = 316) was taken from the Open Access Series of Imaging Studies (OASIS). Brain parenchyma (BP), grey matter (GM), white matter (WM), corpus callosum (CC), and thalamus volumes were calculated. A non-parametric technique was applied to fit the resulting age–volume data. For each age, the BVL/year was derived from the age–volume curves. The resulting BVL/year curves were compared between the two cohorts. For the MPCH cohort, the BVL/year curve of the BP was an increasing function starting from 0.20% at the age of 35 years increasing to 0.52% at 70 years (corresponding values for GM ranged from 0.32 to 0.55%, WM from 0.02 to 0.47%, CC from 0.07 to 0.48%, and thalamus from 0.25 to 0.54%). Mean absolute difference between BVL/year trajectories across the age range of 35–70 years was 0.02% for BP, 0.04% for GM, 0.04% for WM, 0.11% for CC, and 0.02% for the thalamus. Physiological BVL/year rates were remarkably consistent between the two cohorts and independent from the scanner applied. Average BVL/year was clearly age and compartment dependent. These results need to be taken into account when defining cut-off values for pathological annual brain volume loss in disease models, such as multiple sclerosis.