| 1. |
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| 2. |
- Boscato, Noeli, et al.
(author)
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Is bruxism associated with changes in neural pathways? : A systematic review and meta-analysis of clinical studies using neurophysiological techniques
- 2022
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In: Brain Imaging and Behavior. - : Springer. - 1931-7557 .- 1931-7565. ; 16, s. 2268-2280
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Research review (peer-reviewed)abstract
- This study aimed to systematically review the literature to identify clinical studies assessing neuroplasticity changes induced by or associated with bruxism or a tooth-clenching task using neurophysiological techniques. Searches were performed in five electronic databases (PubMed, EMBASE, Scopus, Web of Science, and Google Scholar) in April 2020. This review included clinical studies using neurophysiological techniques to assess neuroplasticity changes in healthy participants before and after a tooth-clenching task or comparing bruxers and non-bruxers. The quality assessment was performed with the Joanna Briggs Institute tool and Grading of Recommendations Assessment, Development, and Evaluation. Meta-analyses were conducted with studies reporting similar comparisons regarding masseter motor evoked potential amplitude and signal change outcomes. Of 151 articles identified in the searches, nine were included, and five proceeded to meta-analysis. Included studies presented moderate to very low methodological quality. From these included studies, eight evaluated bruxers and non-bruxers, of which five of them observed brain activity differences between groups, and three found no differences. Even so, all studies have suggested distinct difference in the central excitability between bruxers and non-bruxers, the meta-analysis revealed no statistically significant differences (P > 0.05). It appears that bruxism seems, indeed, to be associated with distinct differences in the neural pathways related to the control of the jaw-closing muscles, but that considerable variability in terms of classification of bruxism and assessment of neuroplasticity hamper a definite conclusion. Future research projects should take these concerns into consideration in order to further the understanding of bruxism physiology and pathophysiology.
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| 3. |
- Emmert, Kirsten, et al.
(author)
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Active pain coping is associated with the response in real-time fMRI neurofeedback during pain
- 2017
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In: Brain Imaging and Behavior. - : Springer Science and Business Media LLC. - 1931-7557 .- 1931-7565. ; 11:3, s. 712-721
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Journal article (peer-reviewed)abstract
- Real-time functional magnetic resonance imaging (rt-fMRI) neurofeedback is used as a tool to gain voluntary control of activity in various brain regions. Little emphasis has been put on the influence of cognitive and personality traits on neurofeedback efficacy and baseline activity. Here, we assessed the effect of individual pain coping on rt-fMRI neurofeedback during heat-induced pain. Twenty-eight healthy subjects completed the Coping Strategies Questionnaire (CSQ) prior to scanning. The first part of the fMRI experiment identified target regions using painful heat stimulation. Then, subjects were asked to down-regulate the pain target brain region during four neurofeedback runs with painful heat stimulation. Functional MRI analysis included correlation analysis between fMRI activation and pain ratings as well as CSQ ratings. At the behavioral level, the active pain coping (first principal component of CSQ) was correlated with pain ratings during neurofeedback. Concerning neuroimaging, pain sensitive regions were negatively correlated with pain coping. During neurofeedback, the pain coping was positively correlated with activation in the anterior cingulate cortex, prefrontal cortex, hippocampus and visual cortex. Thermode temperature was negatively correlated with anterior insula and dorsolateral prefrontal cortex activation. In conclusion, self-reported pain coping mechanisms and pain sensitivity are a source of variance during rt-fMRI neurofeedback possibly explaining variations in regulation success. In particular, active coping seems to be associated with successful pain regulation.
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| 4. |
- Fathy, YY, et al.
(author)
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Differential insular cortex sub-regional atrophy in neurodegenerative diseases: a systematic review and meta-analysis
- 2020
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In: Brain imaging and behavior. - : Springer Science and Business Media LLC. - 1931-7565 .- 1931-7557. ; 14:6, s. 2799-2816
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Journal article (peer-reviewed)abstract
- The insular cortex is proposed to function as a central brain hub characterized by wide-spread connections and diverse functional roles. As a result, its centrality in the brain confers high metabolic demands predisposing it to dysfunction in disease. However, the functional profile and vulnerability to degeneration varies across the insular sub-regions. The aim of this systematic review and meta-analysis is to summarize and quantitatively analyze the relationship between insular cortex sub-regional atrophy, studied by voxel based morphometry, with cognitive and neuropsychiatric deficits in frontotemporal dementia (FTD), Alzheimer’s disease (AD), Parkinson’s disease (PD), and dementia with Lewy bodies (DLB). We systematically searched through Pubmed and Embase and identified 519 studies that fit our criteria. A total of 41 studies (n = 2261 subjects) fulfilled the inclusion criteria for the meta-analysis. The peak insular coordinates were pooled and analyzed using Anatomic Likelihood Estimation. Our results showed greater left anterior insular cortex atrophy in FTD whereas the right anterior dorsal insular cortex showed larger clusters of atrophy in AD and PD/DLB. Yet contrast analyses did not reveal significant differences between disease groups. Functional analysis showed that left anterior insular cortex atrophy is associated with speech, emotion, and affective-cognitive deficits, and right dorsal atrophy with perception and cognitive deficits. In conclusion, insular sub-regional atrophy, particularly the anterior dorsal region, may contribute to cognitive and neuropsychiatric deficits in neurodegeneration. Our results support anterior insular cortex vulnerability and convey the differential involvement of the insular sub-regions in functional deficits in neurodegenerative diseases.
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| 5. |
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| 6. |
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| 7. |
- Han, Pengfei, et al.
(author)
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Neural processing of odor-associated words : an fMRI study in patients with acquired olfactory loss
- 2020
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In: Brain Imaging and Behavior. - : Springer Science and Business Media LLC. - 1931-7557 .- 1931-7565. ; 14, s. 1164-1174
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Journal article (peer-reviewed)abstract
- Perception of olfactory information is mediated by both bottom-up (from molecules to perception) and top-down (e.g. cross-modal associative learning) processes. Acquired olfactory loss is a frequent disorder which is typically due to alterations in the bottom-up pathway. However, it is unclear how the top-down modulation of olfactory processing is affected by olfactory impairment. Our study aimed to investigate the top-down olfactory processing in patients with acquired olfactory loss and participants with normal olfaction. Using functional MRI, brain responses from 14 patients and 16 healthy controls were assessed during a task of expectation and reading of words with strong olfactory associations (OW) (e.g. “Rose”) and control words with little to no olfactory associations (CW) (e.g. “Door”). The expectation but not reading of the OW was associated with stronger neural activation in the angular gyrus and the inferior frontal gyrus extending to insula in the group of patients. During OW reading, the brain activation in the left OFC and right putamen was negatively correlated with odor identification score in patient and control groups, respectively. In addition, the duration of olfactory loss among patients was positively associated with activation in the left putamen during OW expectation. Taken together, these findings suggest an enhanced top-down olfactory modulation in patients with olfactory loss.
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| 8. |
- Hermann, Andrea, et al.
(author)
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Neural correlates of immediate and prolonged effects of cognitive reappraisal and distraction on emotional experience.
- 2017
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In: Brain Imaging and Behavior. - : Springer Science and Business Media LLC. - 1931-7557 .- 1931-7565. ; 11:5, s. 1227-1237
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Journal article (peer-reviewed)abstract
- Cognitive emotion regulation strategies are important components of cognitive-behavioral therapy (CBT). Additionally, up-regulation and difficulties in the down-regulation of negative feelings are associated with mental disorders. However, little is known about the lasting effects of cognitive emotion regulation strategies on emotional experience and associated neural activation. Therefore, this study investigated immediate and prolonged effects of emotion regulation using cognitive reappraisal and distraction on subjective report and its neural correlates. Twenty-seven healthy females took part in a 2-day functional magnetic resonance imaging study. They were instructed to either up-regulate or down-regulate their negative feelings using a situation-focused cognitive reappraisal strategy, to distract themselves by imagining a specific neutral situation, or to passively look at repeatedly presented aversive and neutral pictures. Re-exposure to the same stimuli without a regulation instruction was conducted one day later. Self-reported negative feelings and blood-oxygen-level-dependent responses served as main outcome variables. As expected, the results show successful immediate up- or down-regulation of negative feelings by cognitive reappraisal and down-regulation of negative feelings by distraction. Furthermore, these changes in negative feelings were correlated with amygdala activation. A lasting effect on emotional experience associated with stronger ventromedial prefrontal cortex activation was found for down-regulation of negative feelings via cognitive reappraisal. Compared to distraction, down-regulation via cognitive reappraisal led to reduced negative feelings and stronger dorso- and ventrolateral prefrontal cortex responses one day later. While cognitive reappraisal and distraction are both effective strategies during active regulation, only cognitive reappraisal had a lasting effect. These findings might have implications for CBT.
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| 9. |
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| 10. |
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| 11. |
- Luders, Eileen, et al.
(author)
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Gray matter increases within subregions of the hippocampal complex after pregnancy
- 2021
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In: Brain Imaging and Behavior. - : Springer Nature. - 1931-7557 .- 1931-7565. ; 15:6, s. 2790-2794
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Journal article (peer-reviewed)abstract
- Neuroimaging findings - although still relatively sparse in the realm of postpartum research - suggest significant tissue increases within the hippocampus or its vicinity after giving birth. Given that the hippocampus is not a homogenous structure, effects may manifest differently across the hippocampal complex. Thus, the goal of this study was to determine the presence, magnitude, and direction of postpartum gray matter changes within five hippocampal subregions, specifically the dentate gyrus, the subiculum, and the subfields of the cornu ammonis (CA1, CA2 and CA3). For this purpose, we analyzed brain images of 14 healthy women acquired at immediate postpartum (within 1-2 days of childbirth) and at late postpartum (at 4-6 weeks after childbirth). Changes in hippocampal gray matter between both time points were calculated for all subregions as well as the hippocampal complex as a whole by integrating imaging-based intensity information with microscopically defined cytoarchitectonic probabilities. Hippocampal gray matter increased significantly within the right subiculum, right CA2, and right CA3. These findings may suggest that brain tissue lost during pregnancy is being restored after giving birth, perhaps even expanded compared to before pregnancy. Possible events on the microanatomical level include dendritic branching as well as the generation of new synapses, glia cells, and blood vessels. Altogether, the outcomes of our study confirm that hippocampal gray matter increases in the female human brain after giving birth, with differential effects across the hippocampal complex.
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| 12. |
- Lyall, DM, et al.
(author)
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Association between APOE e4 and white matter hyperintensity volume, but not total brain volume or white matter integrity
- 2020
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In: Brain imaging and behavior. - : Springer Science and Business Media LLC. - 1931-7565 .- 1931-7557. ; 14:5, s. 1468-1476
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Journal article (peer-reviewed)abstract
- Apolipoprotein (APOE) e4 genotype is an accepted risk factor for accelerated cognitive aging and dementia, though its neurostructural substrates are unclear. The deleterious effects of this genotype on brain structure may increase in magnitude into older age. This study aimed to investigate in UK Biobank the association between APOE e4 allele presence vs. absence and brain imaging variables that have been associated with worse cognitive abilities; and whether this association varies by cross-sectional age. We used brain magnetic resonance imaging (MRI) and genetic data from a general-population cohort: the UK Biobank (N = 8395 after exclusions). We adjusted for the covariates of age in years, sex, Townsend social deprivation scores, smoking history and cardiometabolic diseases. There was a statistically significant association between APOE e4 genotype and increased (i.e. worse) white matter (WM) hyperintensity volumes (standardised beta = 0.088, 95% confidence intervals = 0.036 to 0.139, P = 0.001), a marker of poorer cerebrovascular health. There were no associations with left or right hippocampal, total grey matter (GM) or WM volumes, or WM tract integrity indexed by fractional anisotropy (FA) and mean diffusivity (MD). There were no statistically significant interactions with age. Future research in UK Biobank utilising intermediate phenotypes and longitudinal imaging hold significant promise for this area, particularly pertaining to APOE e4’s potential link with cerebrovascular contributions to cognitive aging.
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| 13. |
- Malik, Saima, et al.
(author)
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Deep TMS of the insula using the H-coil modulates dopamine release: a crossover [C-11] PHNO-PET pilot trial in healthy humans
- 2018
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In: Brain Imaging and Behavior. - : SPRINGER. - 1931-7557 .- 1931-7565. ; 12:5, s. 1306-1317
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Journal article (peer-reviewed)abstract
- Modulating the function of the insular cortex could be a novel therapeutic strategy to treat addiction to a variety of drugs of abuse as this region has been implicated in mediating drug reward and addictive processes. The recent advent of the H-coil has permitted the targeting of deeper brain structures which was not previously feasible. The goal of this study was to bilaterally target the insular region using the H-coil with repetitive Transcranial Magnetic Stimulation (rTMS) and subsequently measure changes in dopamine levels using Positron Emission Tomography (PET) with [11C]-(+)-propyl-hexahydro-naphtho-oxazin (PHNO). This was a within-subject, crossover, blinded and sham-controlled pilot study. Eight healthy, right-handed subjects, aged 19-45, participated in the investigation. All subjects underwent 3 PHNO-PET scans preceded by rTMS (sham, 1Hz or 10Hz), on 3 separate days. Low frequency rTMS (1Hz), targeting the insular cortex, significantly decreased dopamine levels in the substantia nigra, sensorimotor striatum and associative striatum. Replicating this study in tobacco smokers or alcoholics would be a logical follow-up to assess whether H-coil stimulation of the bilateral insula can be employed as a treatment option for addiction. Trial registration: NCT02212405
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| 14. |
- Nickchen, Katharina, et al.
(author)
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Reversal learning reveals cognitive deficits and altered prediction error encoding in the ventral striatum in Huntingtons disease
- 2017
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In: Brain Imaging and Behavior. - : SPRINGER. - 1931-7557 .- 1931-7565. ; 11:6, s. 1862-1872
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Journal article (peer-reviewed)abstract
- Huntingtons disease (HD) is an autosomal dominant neurodegenerative condition characterized by a triad of movement disorder, neuropsychiatric symptoms and cognitive deficits. The striatum is particularly vulnerable to the effects of mutant huntingtin, and cell loss can already be found in presymptomatic stages. Since the striatum is well known for its role in reinforcement learning, we hypothesized to find altered behavioral and neural responses in HD patients in a probabilistic reinforcement learning task performed during functional magnetic resonance imaging. We studied 24 HD patients without central nervous system (CNS)-active medication and 25 healthy controls. Twenty HD patients and 24 healthy controls were able to complete the task. Computational modeling was used to calculate prediction error values and estimate individual parameters. We observed that gray matter density and prediction error signals during the learning task were related to disease stage. HD patients in advanced disease stages appear to use a less complex strategy in the reversal learning task. In contrast, HD patients in early disease stages show intact encoding of learning signals in the degenerating left ventral striatum. This effect appears to be lost with disease progression.
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| 15. |
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| 16. |
- Racine, Annie M, et al.
(author)
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Association of longitudinal white matter degeneration and cerebrospinal fluid biomarkers of neurodegeneration, inflammation and Alzheimer’s disease in late-middle-aged adults
- 2019
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In: Brain imaging and behavior. - : Springer Science and Business Media LLC. - 1931-7565 .- 1931-7557. ; 13:1, s. 41-52
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Journal article (peer-reviewed)abstract
- Alzheimer's disease (AD) is characterized by substantial neurodegeneration, including both cortical atrophy and loss of underlying white matter fiber tracts. Understanding longitudinal alterations to white matter may provide new insights into trajectories of brain change in both healthy aging and AD, and fluid biomarkers may be particularly useful in this effort. To examine this, 151 late-middle-aged participants enriched with risk for AD with at least one lumbar puncture and two diffusion tensor imaging (DTI) scans were selected for analysis from two large observational and longitudinally followed cohorts. Cerebrospinal fluid (CSF) was assayed for biomarkers of AD-specific pathology (phosphorylated-tau/Aβ42 ratio), axonal degeneration (neurofilament light chain protein, NFL), dendritic degeneration (neurogranin), and inflammation (chitinase-3-like protein 1, YKL-40). Linear mixed effects models were performed to test the hypothesis that biomarkers for AD, neurodegeneration, and inflammation, or two-year change in those biomarkers, would be associated with worse white matter health overall and/or progressively worsening white matter health over time. At baseline in the cingulum, phosphorylated-tau/Aβ42 was associated with higher mean diffusivity (MD) overall (intercept) and YKL-40 was associated with increases in MD over time. Two-year change in neurogranin was associated with higher mean diffusivity and lower fractional anisotropy overall (intercepts) across white matter in the entire brain and in the cingulum. These findings suggest that biomarkers for AD, neurodegeneration, and inflammation are potentially important indicators of declining white matter health in a cognitively healthy, late-middle-aged cohort.
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| 17. |
- Ramezani, Mahdi, et al.
(author)
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Fusion analysis of functional MRI data for classification of individuals based on patterns of activation
- 2015
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In: BRAIN IMAGING AND BEHAVIOR. - : Springer Verlag (Germany). - 1931-7557 .- 1931-7565. ; 9:2, s. 149-161
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Journal article (peer-reviewed)abstract
- Classification of individuals based on patterns of brain activity observed in functional MRI contrasts may be helpful for diagnosis of neurological disorders. Prior work for classification based on these patterns have primarily focused on using a single contrast, which does not take advantage of complementary information that may be available in multiple contrasts. Where multiple contrasts are used, the objective has been only to identify the joint, distinct brain activity patterns that differ between groups of subjects; not to use the information to classify individuals. Here, we use joint Independent Component Analysis (jICA) within a Support Vector Machine (SVM) classification method, and take advantage of the relative contribution of activation patterns generated from multiple fMRI contrasts to improve classification accuracy. Young (age: 19-26) and older (age: 57-73) adults (16 each) were scanned while listening to noise alone and to speech degraded with noise, half of which contained meaningful context that could be used to enhance intelligibility. Functional contrasts based on these conditions (and a silent baseline condition) were used within jICA to generate spatially independent joint activation sources and their corresponding modulation profiles. Modulation profiles were used within a non-linear SVM framework to classify individuals as young or older. Results demonstrate that a combination of activation maps across the multiple contrasts yielded an area under ROC curve of 0.86, superior to classification resulting from individual contrasts. Moreover, class separability, measured by a divergence criterion, was substantially higher when using the combination of activation maps.
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| 18. |
- Rauchmann, Boris Stephan, et al.
(author)
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The impact of endurance training and table soccer on brain metabolites in schizophrenia
- 2020
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In: Brain Imaging and Behavior. - : Springer Science and Business Media LLC. - 1931-7557 .- 1931-7565. ; 14:2, s. 515-526
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Journal article (peer-reviewed)abstract
- Higher glutamate and glutamine (together: Glx) and lower N-acetyl-aspartate (NAA) levels were reported in schizophrenia. Endurance training normalizes NAA in the hippocampus, but its effects on other metabolites in the brain and the relationship of metabolites to clinical symptoms remain unknown. For 12 weeks, 20 schizophrenia inpatients (14 men, 6 women) and 23 healthy controls (16 men, 7 women) performed endurance training and a control group of 21 schizophrenia inpatients (15 men, 6 women) played table soccer. A computer-assisted cognitive performance training program was introduced after 6 weeks. We assessed cognitive performance, psychopathological symptoms, and everyday functioning at baseline and after 6 and 12 weeks and performed single voxel magnetic resonance spectroscopy of the hippocampus, left dorsolateral prefrontal cortex (DLPFC), and thalamus. We quantified NAA, Glx, total creatine (tCr), calculated NAA/tCr and Glx/tCr and correlated these ratios with physical fitness, clinical and neurocognitive scores, and everyday functioning. At baseline, in both schizophrenia groups NAA/tCr was lower in the left DLPFC and left hippocampus and Glx/tCr was lower in the hippocampus than in the healthy controls. After 6 weeks, NAA/tCr increased in the left DLPFC in both schizophrenia groups. Brain metabolites did not change significantly in the hippocampus or thalamus, but the correlation between NAA/tCr and Glx/tCr normalized in the left DLPFC. Global Assessment of Functioning improvements correlated with NAA/tCr changes in the left DLPFC. In our study, endurance training and table soccer induced normalization of brain metabolite ratios in the brain circuitry associated with neuronal and synaptic elements, including metabolites of the glutamatergic system.
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| 19. |
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| 20. |
- Stanisic, Nikola, et al.
(author)
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Pain's Adverse Impact on Training-Induced Performance and Neuroplasticity : A Systematic Review
- 2022
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In: Brain Imaging and Behavior. - : Springer. - 1931-7557 .- 1931-7565. ; 16, s. 2281-2306
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Research review (peer-reviewed)abstract
- Motor training is a widely used therapy in many pain conditions. The brain's capacity to undergo functional and structural changes i.e., neuroplasticity is fundamental to training-induced motor improvement and can be assessed by transcranial magnetic stimulation (TMS). The aim was to investigate the impact of pain on training-induced motor performance and neuroplasticity assessed by TMS. The review was carried out in accordance with the PRISMA-guidelines and a Prospero protocol (CRD42020168487). An electronic search in PubMed, Web of Science and Cochrane until December 13, 2019, identified studies focused on training-induced neuroplasticity in the presence of experimentally-induced pain, 'acute pain' or in a chronic pain condition, 'chronic pain'. Included studies were assessed by two authors for methodological quality using the TMS Quality checklist, and for risk of bias using the Newcastle-Ottawa Scale. The literature search identified 231 studies. After removal of 71 duplicates, 160 abstracts were screened, and 24 articles were reviewed in full text. Of these, 17 studies on acute pain (n = 7) or chronic pain (n = 10), including a total of 258 patients with different pain conditions and 248 healthy participants met the inclusion criteria. The most common types of motor training were different finger tasks (n = 6). Motor training was associated with motor cortex functional neuroplasticity and six of seven acute pain studies and five of ten chronic pain studies showed that, compared to controls, pain can impede such trainings-induced neuroplasticity. These findings may have implications for motor learning and performance and with putative impact on rehabilitative procedures such as physiotherapy.
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| 21. |
- Strandberg, Maria, et al.
(author)
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fMRI memory assessment in healthy subjects : a new approach to view lateralization data at an individual level
- 2011
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In: Brain Imaging and Behavior. - : Springer Science and Business Media LLC. - 1931-7557 .- 1931-7565. ; 5:1, s. 1-11
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Journal article (peer-reviewed)abstract
- We present a comprehensive and clinically applicable fMRI test-including both a verbal and a visuospatial task-for assessment of hemispheric specific memory in the medial temporal lobe (MTL). fMRI data was collected from 15 healthy right-handed volunteers. Whole-brain activation was analyzed as well as activation in two regions of interest: the MTL and the anterior speech area. Laterality indices (LI) and LI-curves were calculated using the LI toolbox of Wilke and Lidzba, 2007. The fMRI paradigms successfully visualized memory-related activity in the MTL, the verbal memory measure also provided information of language lateralization. Eleven subjects showed left lateralized verbal encoding in the MTL, visuospatial memory activation was divided equally between left and right, and 14/15 subjects had left lateralized language. Lateralization data at the group level were consistent with previous studies, but a variety of activation effects were found at the individual level indicating differences in strategy during verbal and visuospatial processing. Further studies using the presented method are needed to determine its clinical usefulness.
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| 22. |
- Thompson, Paul M., et al.
(author)
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The ENIGMA Consortium : large-scale collaborative analyses of neuroimaging and genetic data
- 2014
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In: BRAIN IMAGING BEHAV. - : Springer Science and Business Media LLC. - 1931-7557 .- 1931-7565. ; 8:2, s. 153-182
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Journal article (peer-reviewed)abstract
- The Enhancing NeuroImaging Genetics through Meta-Analysis (ENIGMA) Consortium is a collaborative network of researchers working together on a range of large-scale studies that integrate data from 70 institutions worldwide. Organized into Working Groups that tackle questions in neuroscience, genetics, and medicine, ENIGMA studies have analyzed neuroimaging data from over 12,826 subjects. In addition, data from 12,171 individuals were provided by the CHARGE consortium for replication of findings, in a total of 24,997 subjects. By meta-analyzing results from many sites, ENIGMA has detected factors that affect the brain that no individual site could detect on its own, and that require larger numbers of subjects than any individual neuroimaging study has currently collected. ENIGMA's first project was a genome-wide association study identifying common variants in the genome associated with hippocampal volume or intracranial volume. Continuing work is exploring genetic associations with subcortical volumes (ENIGMA2) and white matter microstructure (ENIGMA-DTI). Working groups also focus on understanding how schizophrenia, bipolar illness, major depression and attention deficit/hyperactivity disorder (ADHD) affect the brain. We review the current progress of the ENIGMA Consortium, along with challenges and unexpected discoveries made on the way.
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| 23. |
- Uhlmann, Anne, et al.
(author)
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White matter volume alterations in hair-pulling disorder (trichotillomania)
- 2020
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In: Brain Imaging and Behavior. - : Springer Science and Business Media LLC. - 1931-7557 .- 1931-7565. ; 14:6, s. 2202-2209
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Journal article (peer-reviewed)abstract
- Trichotillomania (TTM) is a disorder characterized by repetitive hair-pulling resulting in hair loss. Key processes affected in TTM comprise affective, cognitive, and motor functions. Emerging evidence suggests that brain matter aberrations in fronto-striatal and fronto-limbic brain networks and the cerebellum may characterize the pathophysiology of TTM. The aim of the present voxel-based morphometry (VBM) study was to evaluate whole brain grey and white matter volume alteration in TTM and its correlation with hair-pulling severity. High-resolution magnetic resonance imaging (3 T) data were acquired from 29 TTM patients and 28 age-matched healthy controls (CTRLs). All TTM participants completed the Massachusetts General Hospital Hair-Pulling Scale (MGH-HPS) to assess illness/pulling severity. Using whole-brain VBM, between-group differences in regional brain volumes were measured. Additionally, within the TTM group, the relationship between MGH-HPS scores, illness duration and brain volumes were examined. All data were corrected for multiple comparisons using family-wise error (FWE) correction at p < 0.05. Patients with TTM showed larger white matter volumes in the parahippocampal gyrus and cerebellum compared to CTRLs. Estimated white matter volumes showed no significant association with illness duration or MGH-HPS total scores. No significant between-group differences were found for grey matter volumes. Our observations suggest regional alterations in cortico-limbic and cerebellar white matter in patients with TTM, which may underlie deficits in cognitive and affective processing. Such volumetric white matter changes may precipitate impaired cortico-cerebellar communication leading to a reduced ability to control hair pulling behavior.
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| 24. |
- Witt, Suzanne T., et al.
(author)
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Evidence for cognitive resource imbalance in adolescents with narcolepsy
- 2018
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In: Brain Imaging and Behavior. - : Springer Science and Business Media LLC. - 1931-7557 .- 1931-7565. ; 12:2, s. 411-424
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Journal article (peer-reviewed)abstract
- The study investigated brain activity changes during performance of a verbal working memory task in a population of adolescents with narcolepsy. Seventeen narcolepsy patients and twenty healthy controls performed a verbal working memory task during simultaneous fMRI and EEG acquisition. All subjects also underwent MRS to measure GABA and Glutamate concentrations in the medial prefrontal cortex. Activation levels in the default mode network and left middle frontal gyrus were examined to investigate whether narcolepsy is characterized by an imbalance in cognitive resources. Significantly increased deactivation within the default mode network during task performance was observed for the narcolepsy patients for both the encoding and recognition phases of the task. No evidence for task performance deficits or reduced activation within the left middle frontal gyrus was noted for the narcolepsy patients. Correlation analyses between the spectroscopy and fMRI data indicated that deactivation of the anterior aspect of the default mode in narcolepsy patients correlated more with increased concentrations of Glutamate and decreased concentrations of GABA. In contrast, deactivation in the default mode was correlated with increased concentrations of GABA and decreased concentrations of Glutamate in controls. The results suggested that narcolepsy is not characterized by a deficit in working memory but rather an imbalance of cognitive resources in favor of monitoring and maintaining attention over actual task performance. This points towards dysregulation within the sustained attention system being the origin behind self-reported cognitive difficulties in narcolepsy.
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