New resting-state fMRI related studies at PubMed

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Resting-State NIRS-EEG in Unresponsive Patients with Acute Brain Injury: A Proof-of-Concept Study.

Sun, 04/26/2020 - 16:00
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Resting-State NIRS-EEG in Unresponsive Patients with Acute Brain Injury: A Proof-of-Concept Study.

Neurocrit Care. 2020 Apr 24;:

Authors: Othman MH, Bhattacharya M, Møller K, Kjeldsen S, Grand J, Kjaergaard J, Dutta A, Kondziella D

Abstract
BACKGROUND: Neurovascular-based imaging techniques such as functional MRI (fMRI) may reveal signs of consciousness in clinically unresponsive patients but are often subject to logistical challenges in the intensive care unit (ICU). Near-infrared spectroscopy (NIRS) is another neurovascular imaging technique but low cost, can be performed serially at the bedside, and may be combined with electroencephalography (EEG), which are important advantages compared to fMRI. Combined NIRS-EEG, however, has never been evaluated for the assessment of neurovascular coupling and consciousness in acute brain injury.
METHODS: We explored resting-state oscillations in eight-channel NIRS oxyhemoglobin and eight-channel EEG band-power signals to assess neurovascular coupling, the prerequisite for neurovascular-based imaging detection of consciousness, in patients with acute brain injury in the ICU (n = 9). Conscious neurological patients from step-down units and wards served as controls (n = 14). Unsupervised adaptive mixture-independent component analysis (AMICA) was used to correlate NIRS-EEG data with levels of consciousness and clinical outcome.
RESULTS: Neurovascular coupling between NIRS oxyhemoglobin (0.07-0.13 Hz) and EEG band-power (1-12 Hz) signals at frontal areas was sensitive and prognostic to changing consciousness levels. AMICA revealed a mixture of five models from EEG data, with the relative probabilities of these models reflecting levels of consciousness over multiple days, although the accuracy was less than 85%. However, when combined with two channels of bilateral frontal neurovascular coupling, weighted k-nearest neighbor classification of AMICA probabilities distinguished unresponsive patients from conscious controls with > 90% accuracy (positive predictive value 93%, false discovery rate 7%) and, additionally, identified patients who subsequently failed to recover consciousness with > 99% accuracy.
DISCUSSION: We suggest that NIRS-EEG for monitoring of acute brain injury in the ICU is worthy of further exploration. Normalization of neurovascular coupling may herald recovery of consciousness after acute brain injury.

PMID: 32333214 [PubMed - as supplied by publisher]

Cortical source localization of sleep-stage specific oscillatory activity.

Sun, 04/26/2020 - 16:00
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Cortical source localization of sleep-stage specific oscillatory activity.

Sci Rep. 2020 Apr 24;10(1):6976

Authors: Brancaccio A, Tabarelli D, Bigica M, Baldauf D

Abstract
The oscillatory features of non-REM sleep states have been a subject of intense research over many decades. However, a systematic spatial characterization of the spectral features of cortical activity in each sleep state is not available yet. Here, we used magnetoencephalography (MEG) and electroencephalography (EEG) recordings during night sleep. We performed source reconstruction based on the individual subject's anatomical magnetic resonance imaging (MRI) scans and spectral analysis on each non-REM sleep epoch in eight standard frequency bands, spanning the complete spectrum, and computed cortical source reconstructions of the spectral contrasts between each sleep state in comparison to the resting wakefulness. Despite not distinguishing periods of high and low activity within each sleep stage, our results provide new information about relative overall spectral changes in the non-REM sleep stages.

PMID: 32332806 [PubMed - as supplied by publisher]

Music Intervention Reduces Persistent Fibromyalgia Pain and Alters Functional Connectivity Between the Insula and Default Mode Network.

Sat, 04/25/2020 - 15:00
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Music Intervention Reduces Persistent Fibromyalgia Pain and Alters Functional Connectivity Between the Insula and Default Mode Network.

Pain Med. 2020 Apr 24;:

Authors: Usui C, Kirino E, Tanaka S, Inami R, Nishioka K, Hatta K, Nakajima T, Nishioka K, Inoue R

Abstract
OBJECTIVE: The aims of the present study were to examine the effects of short-term music interventions among patients with fibromyalgia (FM) and to clarify the alterations in functional connectivity and persistent pain.
DESIGN: Pilot study.
SETTING: All participants were evaluated at Juntendo University from November 2017 to January 2019.
SUBJECTS: We enrolled female patients who had been clinically diagnosed with FM (N = 23).
METHODS: All participants listened to Mozart's Duo for Violin and Viola No. 1, K. 423, in a quiet room for 17 minutes. We compared the degree of pain using resting-state functional magnetic resonance imaging and the numeric rating scale before and after listening to music.
RESULTS: Pain scores were significantly reduced after listening to music. Further, we observed there was a significant difference in connectivity between the right insular cortex (IC) and posterior cingulate cortex (PCC)/precuneus (PCu) before and after listening to music. We also found that the difference between the right IC-PCu connectivity and the difference in pain scores were significantly correlated.
CONCLUSIONS: We found that a short period of music intervention reduced chronic pain and altered functional IC-default mode network connectivity. Furthermore, music potentially normalized the neural network via IC-default mode network connectivity, yielding temporary pain relief in patients with FM. Further longitudinal studies with larger sample sizes are required to confirm these results.

PMID: 32330259 [PubMed - as supplied by publisher]

Language lateralization from task-based and resting state functional MRI in patients with epilepsy.

Sat, 04/25/2020 - 15:00
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Language lateralization from task-based and resting state functional MRI in patients with epilepsy.

Hum Brain Mapp. 2020 Apr 24;:

Authors: Rolinski R, You X, Gonzalez-Castillo J, Norato G, Reynolds RC, Inati SK, Theodore WH

Abstract
We compared resting state (RS) functional connectivity and task-based fMRI to lateralize language dominance in 30 epilepsy patients (mean age = 33; SD = 11; 12 female), a measure used for presurgical planning. Language laterality index (LI) was calculated from task fMRI in frontal, temporal, and frontal + temporal regional masks using LI bootstrap method from SPM12. RS language LI was assessed using two novel methods of calculating RS language LI from bilateral Broca's area seed based connectivity maps across regional masks and multiple thresholds (p < .05, p < .01, p < .001, top 10% connections). We compared LI from task and RS fMRI continuous values and dominance classifications. We found significant positive correlations between task LI and RS LI when functional connectivity thresholds were set to the top 10% of connections. Concordance of dominance classifications ranged from 20% to 30% for the intrahemispheric resting state LI method and 50% to 63% for the resting state LI intra- minus interhemispheric difference method. Approximately 40% of patients left dominant on task showed RS bilateral dominance. There was no difference in LI concordance between patients with right-sided and left-sided resections. Early seizure onset (<6 years old) was not associated with atypical language dominance during task-based or RS fMRI. While a relationship between task LI and RS LI exists in patients with epilepsy, language dominance is less lateralized on RS than task fMRI. Concordance of language dominance classifications between task and resting state fMRI depends on brain regions surveyed and RS LI calculation method.

PMID: 32329951 [PubMed - as supplied by publisher]

Fronto-thalamic structural and effective connectivity and delusions in schizophrenia: a combined DTI/DCM study.

Sat, 04/25/2020 - 15:00
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Fronto-thalamic structural and effective connectivity and delusions in schizophrenia: a combined DTI/DCM study.

Psychol Med. 2020 Apr 24;:1-11

Authors: Csukly G, Szabó Á, Polgár P, Farkas K, Gyebnár G, Kozák LR, Stefanics G

Abstract
BACKGROUND: Schizophrenia (SZ) is a complex disorder characterized by a range of behavioral and cognitive symptoms as well as structural and functional alterations in multiple cortical and subcortical structures. SZ is associated with reduced functional network connectivity involving core regions such as the anterior cingulate cortex (ACC) and the thalamus. However, little is known whether effective coupling, the directed influence of one structure over the other, is altered during rest in the ACC-thalamus network.
METHODS: We collected resting-state fMRI and diffusion-weighted MRI data from 18 patients and 20 healthy controls. We analyzed fronto-thalamic effective connectivity using dynamic causal modeling for cross-spectral densities in a network consisting of the ACC and the left and right medio-dorsal thalamic regions. We studied structural connectivity using fractional anisotropy (FA).
RESULTS: We found decreased coupling strength from the right thalamus to the ACC and from the right thalamus to the left thalamus, as well as increased inhibitory intrinsic connectivity in the right thalamus in patients relative to controls. ACC-to-left thalamus coupling strength correlated with the Positive and Negative Syndrome Scale (PANSS) total positive syndrome score and with delusion score. Whole-brain structural analysis revealed several tracts with reduced FA in patients, with a maximum decrease in white matter tracts containing fronto-thalamic and cingulo-thalamic fibers.
CONCLUSIONS: We found altered effective and structural connectivity within the ACC-thalamus network in SZ. Our results indicate that ACC-thalamus network activity at rest is characterized by reduced thalamus-to-ACC coupling. We suggest that positive symptoms may arise as a consequence of compensatory measures to imbalanced fronto-thalamic coupling.

PMID: 32329710 [PubMed - as supplied by publisher]

Baclofen-induced Changes in the Resting Brain Modulate Smoking Cue Reactivity: A Double-blind Placebo-controlled Functional Magnetic Resonance Imaging Study in Cigarette Smokers.

Sat, 04/25/2020 - 15:00
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Baclofen-induced Changes in the Resting Brain Modulate Smoking Cue Reactivity: A Double-blind Placebo-controlled Functional Magnetic Resonance Imaging Study in Cigarette Smokers.

Clin Psychopharmacol Neurosci. 2020 May 31;18(2):289-302

Authors: Ketcherside A, Jagannathan K, Dolui S, Hager N, Spilka N, Nutor C, Rao H, Franklin T, Wetherill R

Abstract
Objective: Smoking cue-(SC) elicited craving can lead to relapse in SC-vulnerable individuals. Thus, identifying treatments that target SC-elicited craving is a top research priority. Reduced drug cue neural activity is associated with recovery and is marked by a profile of greater tonic (resting) activation in executive control regions, and increased connectivity between executive and salience regions. Evidence suggests the GABA-B agonist baclofen can reduce drug cue-elicited neural activity, potentially through its actions on the resting brain. Based on the literature, we hypothesize that baclofen's effects in the resting brain can predict its effects during SC exposure.
Methods: In this longitudinal, double blind, placebo-controlled neuropharmacological study 43 non-abstinent, sated treatment-seeking cigarette smokers (63% male) participated in an fMRI resting-state scan and a SC-reactivity task prior to (T1) and 3 weeks following randomization (T2; baclofen: 80 mg/day; n = 21). Subjective craving reports were acquired before and after SC exposure to explicitly examine SC-induced craving.
Results: Whole-brain full-factorial analysis revealed a group-by-time interaction with greater resting brain activation of the right dorsolateral prefrontal cortex (dlPFC) at T2 in the baclofen group (BAC) (pFWEcorr = 0.02), which was associated with reduced neural responses to SCs in key cue-reactive brain regions; the anterior ventral insula and ventromedial prefrontal cortex (pFWEcorr < 0.01). BAC, but not the placebo group reported decreased SC-elicited craving (p = 0.02).
Conclusion: Results suggest that baclofen mitigates the reward response to SCs through an increase in tonic activation of the dlPFC, an executive control region. Through these mechanisms, baclofen may offer SC-vulnerable smokers protection from SC-induced relapse.

PMID: 32329309 [PubMed]

Brain bases of recovery following cognitive rehabilitation for traumatic brain injury: a preliminary study.

Sat, 04/25/2020 - 15:00
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Brain bases of recovery following cognitive rehabilitation for traumatic brain injury: a preliminary study.

Brain Imaging Behav. 2020 Apr 23;:

Authors: Gimbel SI, Ettenhofer ML, Cordero E, Roy M, Chan L

Abstract
Many patients with traumatic brain injury (TBI) have persistent cognitive deficits, including decreased attention and working memory. This preliminary study examined fMRI data from a clinical trial implementing a 4-week virtual reality driving intervention to assess how sustained training can improve deficits related to traumatic brain injury. Previously-reported behavioral findings showed improvements in working memory and processing speed in those who received the intervention; this report explores the brain bases of these effects by comparing neural activity related to working memory (n-back task) and resting state connectivity before and after the intervention. In the baseline visit (n = 24), working memory activity was prominent in bilateral DLPFC and prefrontal cortex, anterior insula, medial superior frontal gyrus, left thalamus, bilateral supramarginal / angular gyrus, precuneus, and left posterior middle temporal gyrus. Following intervention, participants showed less global activation on the n-back task, with regions of activity only in the bilateral middle frontal cortex, posterior middle frontal gyrus, and supramarginal gyrus. Activity related to working memory load was reduced for the group that went through the intervention (n = 7) compared to the waitlist control group (n = 4). These results suggest that successful cognitive rehabilitation of working memory in TBI may be associated with increased efficiency of brain networks, evidenced by reduced activation of brain activity during cognitive processing. These results highlight the importance of examining brain activity related to cognitive rehabilitation of attention and working memory after brain injury.

PMID: 32328915 [PubMed - as supplied by publisher]

Preserved network functional connectivity underlies cognitive reserve in multiple sclerosis.

Sat, 04/25/2020 - 15:00
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Preserved network functional connectivity underlies cognitive reserve in multiple sclerosis.

Hum Brain Mapp. 2019 12 15;40(18):5231-5241

Authors: Fuchs TA, Benedict RHB, Bartnik A, Choudhery S, Li X, Mallory M, Oship D, Yasin F, Ashton K, Jakimovski D, Bergsland N, Ramasamy DP, Weinstock-Guttman B, Zivadinov R, Dwyer MG

Abstract
Cognitive reserve is one's mental resilience or resistance to the effects of structural brain damage. Reserve effects are well established in people with multiple sclerosis (PwMS) and Alzheimer's disease, but the neural basis of this phenomenon is unclear. We aimed to investigate whether preservation of functional connectivity explains cognitive reserve. Seventy-four PwMS and 29 HCs underwent neuropsychological assessment and 3 T MRI. Structural damage measures included gray matter (GM) atrophy and network white matter (WM) tract disruption between pairs of GM regions. Resting-state functional connectivity was also assessed. PwMS exhibited significantly impaired cognitive processing speed (t = 2.14, p = .037) and visual/spatial memory (t = 2.72, p = .008), and had significantly greater variance in functional connectivity relative to HCs within relevant networks (p < .001, p < .001, p = .016). Higher premorbid verbal intelligence, a proxy for cognitive reserve, predicted relative preservation of functional connectivity despite accumulation of GM atrophy (standardized-β = .301, p = .021). Furthermore, preservation of functional connectivity attenuated the impact of structural network WM tract disruption on cognition (β = -.513, p = .001, for cognitive processing speed; β = -.209, p = .066, for visual/spatial memory). The data suggests that preserved functional connectivity explains cognitive reserve in PwMS, helping to maintain cognitive capacity despite structural damage.

PMID: 31444887 [PubMed - indexed for MEDLINE]

Delineating functional segregations of the human middle temporal gyrus with resting-state functional connectivity and coactivation patterns.

Sat, 04/25/2020 - 15:00
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Delineating functional segregations of the human middle temporal gyrus with resting-state functional connectivity and coactivation patterns.

Hum Brain Mapp. 2019 12 15;40(18):5159-5171

Authors: Xu J, Lyu H, Li T, Xu Z, Fu X, Jia F, Wang J, Hu Q

Abstract
Although the middle temporal gyrus (MTG) has been parcellated into subregions with distinguished anatomical connectivity patterns, whether the structural topography of MTG can inform functional segregations of this area remains largely unknown. Accumulating evidence suggests that the brain's underlying organization and function can be directly and effectively delineated with resting-state functional connectivity (RSFC) by identifying putative functional boundaries between cortical areas. Here, RSFC profiles were used to explore functional segregations of the MTG and defined four subregions from anterior to posterior in two independent datasets, which showed a similar pattern with MTG parcellation scheme obtained using anatomical connectivity. The functional segregations of MTG were further supported by whole brain RSFC, coactivation, and specific RFSC, and coactivation mapping. Furthermore, the fingerprint with predefined 10 networks and functional characterizations of each subregion using meta-analysis also identified functional distinction between subregions. The specific connectivity analysis and functional characterization indicated that the bilateral most anterior subregions mainly participated in social cognition and semantic processing; the ventral middle subregions were involved in social cognition in left hemisphere and auditory processing in right hemisphere; the bilateral ventro-posterior subregions participated in action observation, whereas the left subregion was also involved in semantic processing; both of the dorsal subregions in superior temporal sulcus were involved in language, social cognition, and auditory processing. Taken together, our findings demonstrated MTG sharing similar structural and functional topographies and provide more detailed information about the functional organization of the MTG, which may facilitate future clinical and cognitive research on this area.

PMID: 31423713 [PubMed - indexed for MEDLINE]

Word up - Experiential and neurocognitive evidence for associations between autistic symptomology and a preference for thinking in the form of words.

Fri, 04/24/2020 - 13:40

Word up - Experiential and neurocognitive evidence for associations between autistic symptomology and a preference for thinking in the form of words.

Cortex. 2020 Mar 27;128:88-106

Authors: Turnbull A, Garfinkel SN, Ho NSP, Critchley HD, Bernhardt BC, Jefferies E, Smallwood J

Abstract
Autism symptomology has a profound impact on cognitive and affective functioning, yet we know relatively little about how it shapes patterns of ongoing thought. In an exploratory study in a large population of neurotypical individuals, we used experience sampling to characterise the relationship between ongoing cognition and self-reported autistic traits. We found that with increasing autistic symptom score, cognition was characterised by thinking more in words than images. Analysis of structural neuroimaging data found that autistic traits linked to social interaction were associated with greater cortical thickness in a region of lingual gyrus (LG) within the occipital cortex. Analysis of resting state functional neuroimaging data found autistic traits were associated with stronger connectivity between the LG and a region of motor cortex. Importantly, the strength of connectivity between the LG and motor cortex moderated the link between autistic symptoms and thinking in words: individuals showing higher connectivity showed a stronger association between autistic traits and thinking in words. Together we provide behavioural and neural evidence linking autistic traits to the tendency to think in words which may be rooted in underlying cortical organisation. These observations lay the groundwork for research into the form and content of self-generated thoughts in individuals with the established diagnosis of autism.

PMID: 32325277 [PubMed - as supplied by publisher]

Myeloarchitecture Gradients In The Human Insula: Histological Underpinnings And Association To Intrinsic Functional Connectivity.

Fri, 04/24/2020 - 13:40

Myeloarchitecture Gradients In The Human Insula: Histological Underpinnings And Association To Intrinsic Functional Connectivity.

Neuroimage. 2020 Apr 20;:116859

Authors: Royer J, Paquola C, Larivière S, Vos de Wael R, Tavakol S, Lowe AJ, Benkarim O, Evans AC, Bzdok D, Smallwood J, Frauscher B, Bernhardt BC

Abstract
Insular cortex is a core hub involved in multiple cognitive and socio-affective processes. Yet, the anatomical mechanisms that explain how it is involved in such a diverse array of functions remain incompletely understood. Here, we tested the hypothesis that changes in myeloarchitecture across the insular cortex explain how it can be involved in many different facets of cognitive function. Detailed intracortical profiling, performed across hundreds of insular locations on the basis of myelin-sensitive magnetic resonance imaging (MRI), was compressed into a lower-dimensional space uncovering principal axes of myeloarchitectonic variation. Leveraging two datasets with different high-resolution MRI contrasts, we obtained robust support for two principal dimensions of insular myeloarchitectonic differentiation in vivo, one running from ventral anterior to posterior banks and one radiating from dorsal anterior towards both ventral anterior and posterior subregions. Analyses of post mortem 3D histological data showed that the antero-posterior axis was mirrored in cytoarchitectural markers, even when controlling for sulco-gyral folding. Resting-state functional connectomics in the same individuals and ad hoc meta-analyses showed that myelin gradients in the insula relate to diverse affiliation to macroscale intrinsic functional systems, showing differential shifts in functional network embedding across each myelin-derived gradient. Collectively, our findings offer a novel approach to capture structure-function interactions of a key node of the limbic system, and suggest a multidimensional structural basis underlying the diverse functional roles of the insula.

PMID: 32325211 [PubMed - as supplied by publisher]

Alterations in Brain Function After Cognitive Behavioral Therapy for Migraine in Children and Adolescents.

Fri, 04/24/2020 - 13:40

Alterations in Brain Function After Cognitive Behavioral Therapy for Migraine in Children and Adolescents.

Headache. 2020 Apr 23;:

Authors: Nahman-Averbuch H, Schneider VJ, Chamberlin LA, Kroon Van Diest AM, Peugh JL, Lee GR, Radhakrishnan R, Hershey AD, King CD, Coghill RC, Powers SW

Abstract
OBJECTIVES: This basic mechanistic study examined the changes in brain activation and resting-state connectivity after 8 weeks of CBT in youth with migraine.
BACKGROUND: Cognitive behavioral therapy (CBT) is a psychological intervention that is effective in reducing pain in migraine patients. However, the neural mechanisms underlying CBT in adolescents with migraine are not yet known.
METHODS: Eighteen adolescents with migraine (15 females, age 15.1 ± 2.1 years [mean ± SD]) completed 8 weekly CBT sessions. Before the first and after the final CBT session, participants underwent structural and resting-state blood-oxygen-level-dependent contrast MRI scans. Arterial spin labeling was also used to examine brain activation during the resting state. For connectivity analyses, the right and left amygdala were chosen as seed regions. Relationships of the time courses within these seeds with voxels across the whole brain were evaluated.
RESULTS: Headache frequency decreased from 15 ± 7.4 headaches per month before CBT to 10 ± 7.4 after CBT (P < .001). After CBT, greater brain activations in frontal regions involved in cognitive regulation of pain were found. In addition, after CBT increased connectivity between the amygdala and frontal regions was observed. Associations between brain activation and amygdalar connectivity with a reduction in headache frequency were also observed.
CONCLUSIONS: Alterations in brain function and amygdalar connectivity with areas involved in nociceptive processing, cognitive function, and emotional regulation may underlie the ability of CBT to aid in the prevention of headaches in migraine patients.

PMID: 32323877 [PubMed - as supplied by publisher]

Abnormal large-scale resting-state functional networks in drug-free major depressive disorder.

Fri, 04/24/2020 - 13:40

Abnormal large-scale resting-state functional networks in drug-free major depressive disorder.

Brain Imaging Behav. 2020 Apr 22;:

Authors: Luo L, Wu H, Xu J, Chen F, Wu F, Wang C, Wang J

Abstract
Major depressive disorder (MDD) is associated with aberrant function and interaction encompassing large parts of cortical, subcortical and limbic regions that always organized into integrative networks implicated in specific tasks. And cumulative evidence suggests that MDD can be understood as a disorder of dysregulated network. Our study used resting-state fMRI and independent component analysis (ICA) to investigate intrinsic functional connectivity (FC) within and between resting-state networks (RSNs) in 27 drug-free MDD patients and 54 healthy control subjects (HCs). Granger causality analysis (GCA) was further used to identify the direct functional interaction between RSNs. We identified sixteen independent components (ICs) as meaningful RSNs. Compared with HCs, the MDD had significantly decreased intra-FC within lateral visual network (VN), parietal network (PN) and posterior default mode network (pDMN), decreased inter-FC between fronto-parietal network (FPN) and subcortical network, between pDMN and anterior DMN, and increased inter-FC between salience network and FPN, and enhanced effective connectivity from VN to PN and to cerebellum network. The functional synchronization of pDMN was negatively correlated with Hamilton Depression Rating Scores. The relatively small number of MDD, the use of medication and the application challenges of GCA on fMRI data may limit the interpretability. These findings indicated that MDD is indeed a disorder of dysregulated network, especially in the functional networks implicated in self-referential activities and emotional visual processing.

PMID: 32323112 [PubMed - as supplied by publisher]

Altered intrinsic brain activity and regional cerebral blood flow in patients with chronic neck and shoulder pain.

Fri, 04/24/2020 - 13:40

Altered intrinsic brain activity and regional cerebral blood flow in patients with chronic neck and shoulder pain.

Pol J Radiol. 2020;85:e155-e162

Authors: Yue X, Du Y

Abstract
Purpose: To identify the changes of intrinsic brain activity and regional cerebral blood flow in patients with chronic neck and shoulder pain (CNSP) by using amplitude of low-frequency fluctuation (ALFF) analysis and arterial spin labelling study.
Material and methods: In total, 28 CNSP patients and 25 age-matched and sex-matched healthy controls (HCs) participated in the study. Resting-state functional magnetic resonance imaging (rs-fMRI) and arterial spin labelling (ASL) MRI were acquired. Correlations between ALFF and cerebral blood flow (CBF) were analysed. Subsequently, the differences in ALFF and CBF were compared in the two groups. Finally, the visual analogue scale (VAS) was also assessed in the CNSP group.
Results: Compared with HCs, CNSP patients showed significantly abnormal ALFF and CBF in several brain regions, including the cerebellum posterior lobe, middle orbitofrontal gyrus, medial superior frontal gyrus, middle temporal gyrus, precuneus, cingulate gyrus, middle occipital gyrus, middle frontal gyrus, postcentral gyrus, precentral gyrus, and superior parietal gyrus. Correlation analysis showed that the ALFF value of the medial superior frontal gyrus positively correlated with the VAS score. However, no correlation was found between the CBF values and the VAS score.
Conclusions: The altered ALFF and CBF values in CNSP patients were observed in different pain-related brain regions that were involved in pain modulation and perception. The combination of rs-fMRI and ASL MRI might provide complementary information for increasing our understanding of the neuropathology in CNSP.

PMID: 32322322 [PubMed]

The use of functional magnetic resonance imaging techniques in the evaluation of patients with disorders of consciousness: a case report.

Fri, 04/24/2020 - 13:40

The use of functional magnetic resonance imaging techniques in the evaluation of patients with disorders of consciousness: a case report.

Pol J Radiol. 2020;85:e118-e124

Authors: Gębska-Kośla K, Głąbiński A, Sabiniewicz M, Wolak T, Wachowski M, Kruczykowska L, Majos A

Abstract
Purpose: The management of patients with disorders of consciousness (DOC) constitutes a challenge for clinicians.
Case report: We present the case of a 66-year-old man who developed coma with subsequent DOC after a severe traumatic brain injury. Behavioural assessment constitutes the gold standard in the evaluation of patients with DOC. In the case presented herein the neuropsychological findings were ambiguous, and the patient underwent functional magnetic resonance imaging (fMRI) to determine whether he was in a vegetative state or minimally conscious state. Three paradigms: passive, active, and resting state fMRI were used to study the brain activity in our patient.
Conclusions: fMRI provided reliable evidence of preserved minimal consciousness. The neuroimaging techniques used in our patient were vital for his further treatment.

PMID: 32322317 [PubMed]

Reduced Dynamic Complexity of BOLD Signals Differentiates Mild Cognitive Impairment From Normal Aging.

Fri, 04/24/2020 - 13:40

Reduced Dynamic Complexity of BOLD Signals Differentiates Mild Cognitive Impairment From Normal Aging.

Front Aging Neurosci. 2020;12:90

Authors: Zheng H, Onoda K, Nagai A, Yamaguchi S

Abstract
Mild cognitive impairment (MCI) is characterized as a transitional phase between cognitive decline associated with normal aging and Alzheimer's disease (AD). Resting-state functional magnetic resonance imaging (fMRI) measuring blood oxygenation level-dependent (BOLD) signals provides complementary information considered essential for understanding disease progression. Previous studies suggested that multi-scale entropy (MSE) analysis quantifying the complexity of BOLD signals is a novel and promising method for investigating neurodegeneration associated with cognitive decline in different stages of MCI. Therefore, the current study used MSE to explore the changes in the complexity of resting-state brain BOLD signals in patients with early MCI (EMCI) and late MCI (LMCI). We recruited 345 participants' data from the Alzheimer's Disease Neuroimaging Initiative database, including 176 normal control (NC) subjects, 87 patients with EMCI and 82 patients with LMCI. We observed a significant reduction of brain signal complexity toward regularity in the left fusiform gyrus region in the EMCI group and in the rostral anterior cingulate cortex in the LMCI group. Our results extend prior work by revealing that significant reductions of brain BOLD signal complexity can be detected in different stages of MCI independent of age, sex and regional atrophy. Notably, the reduction of BOLD signal complexity in the rostral anterior cingulate cortex was significantly associated with greater risk of progression to AD. The present study thus identified MSE as a potential imaging biomarker for the early diagnosis of pre-clinical Alzheimer's disease and provides further insights into the neuropathology of cognitive decline in prodromal AD.

PMID: 32322197 [PubMed]

Clinical predictivity of thalamic sub-regional connectivity in clinically isolated syndrome: a 7-year study.

Fri, 04/24/2020 - 13:40

Clinical predictivity of thalamic sub-regional connectivity in clinically isolated syndrome: a 7-year study.

Mol Psychiatry. 2020 Apr 22;:

Authors: Hidalgo de la Cruz M, Valsasina P, Mesaros S, Meani A, Ivanovic J, Martinovic V, Drulovic J, Filippi M, Rocca MA

Abstract
Here, we explored trajectories of sub-regional thalamic resting state (RS) functional connectivity (FC) modifications occurring in clinically isolated syndrome (CIS) patients early after their first clinical episode, and assessed their relationship with disability over 7 years. RS fMRI and clinical data were prospectively acquired from 59 CIS patients and 13 healthy controls (HC) over 2 years. A clinical re-assessment was performed in 53 (89%) patients after 7 years. Using a structural connectivity-based atlas, five thalamic sub-regions (frontal, motor, postcentral, occipital, and temporal) were used for seed-based RS FC. Thalamic RS FC abnormalities and their longitudinal changes were correlated with disability. Thirty-nine (66.1%) patients suffered a second clinical relapse, but the median EDSS remained stable over time. At baseline, CIS patients vs HC showed reduced RS FC (p < 0.001, uncorrected) with: (1) frontal cortices, for the whole thalamus, occipital, postcentral, and temporal thalamic sub-regions, (2) occipital cortices, for the occipital thalamic sub-region. In CIS, the longitudinal analysis revealed at year 2 vs baseline: (1) no significant whole-thalamic RS FC changes; (2) reduction of motor, postcentral, and temporal sub-regional RS FC with occipital cortices (p < 0.05, corrected); (3) an increase (p < 0.001, uncorrected) of postcentral and occipital sub-regional thalamic RS FC with frontal cortices, left putamen, and ipsi- and contralateral thalamus, this latter correlating with less severe clinical disability at year 7. Thalamo-cortical disconnections were present in CIS mainly in thalamic sub-regions closer to the third ventricle early after the demyelinating event, evolved in the subsequent 2 years, and were associated with long-term clinical disability.

PMID: 32322087 [PubMed - as supplied by publisher]

Functional connectivity changes of nucleus Accumbens Shell portion in left mesial temporal lobe epilepsy patients.

Thu, 04/23/2020 - 12:40
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Functional connectivity changes of nucleus Accumbens Shell portion in left mesial temporal lobe epilepsy patients.

Brain Imaging Behav. 2020 Apr 21;:

Authors: Yang R, Zhao X, Liu J, Yao X, Hou F, Xu Y, Feng Q

Abstract
Growing evidence has supported that the nucleus accumbens (NAc), especially its shell portion, has been involved in epileptogenesis. However, relevant studies on vivo human brain are quite limited. In this study, we investigated left mesial temporal lobe epilepsy (MTLE) related function connectivity (FC) changes of NAc subregions using resting-state functional magnetic resonance imaging. We calculated functional connectivity from two NAc subregions to both whole brain and 16 related targets. Two-sample t-test (Alphasim multiple comparisons corrected) was performed to identify the effect of the disease on each seed's whole brain network. Repeated-measures ANOVA and Post hoc pairwise t test (Bonferroni corrections) were performed to visualize the seed to target FC group differences in each subdivision. In whole brain FC networks, neither the left or right core show different FC changes. The left shell showed decreased FC with a cluster located around the right inferior frontal gyrus. The right shell portion showed increased FC with a cluster located around the left inferior temporal gyrus. The seed to targets results showed that the left shell of LTLE group exhibited lower FC with left posterior-parahippocampal gyrus and right caudate, putamen, thalamus, paracingulate gyrus but higher FC with right subcallosal cortex. The right core of LTLE group exhibited higher FC with right frontal pole and the right shell exhibited lower FC with left thalamus and left anterior-parahippocampal gyrus. This is the first study to investigate the functional connectivity changes of NAc subdivisions of epilepsy in vivo human brain. Our results showed that the left MTLE related FC changes on NAc are mainly on shell portion rather than core. The decrease FC between the left shell and right frontal area and the decrease FC between the right shell and left temporal area suggested they serve vital roles for MTLE.

PMID: 32318911 [PubMed - as supplied by publisher]

Frequency-Aware Summarization of Resting-State fMRI Data.

Thu, 04/23/2020 - 12:40
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Frequency-Aware Summarization of Resting-State fMRI Data.

Front Syst Neurosci. 2020;14:16

Authors: Yaesoubi M, Silva RF, Iraji A, Calhoun VD

Abstract
Many brain imaging modalities reveal interpretable patterns after the data dimensionality is reduced and summarized via data-driven approaches. In functional magnetic resonance imaging (fMRI) studies, such summarization is often achieved through independent component analysis (ICA). ICA transforms the original data into a relatively small number of interpretable bases in voxel space (referred to as ICA spatial components, or spatial maps) and corresponding bases in the time domain (referred to as time-courses of corresponding spatial maps) In this work, we use the word "basis" to broadly refer to either of the two factors resulting from the transformation. A precise summarization for fMRI requires accurately detecting co-activation of voxels by measuring temporal dependence. Accurate measurement of dependence requires a proper understanding of the underlying temporal characteristics of the data. One way to understand such characteristics is to study the frequency spectrum of fMRI data. Researchers have argued that information regarding the underlying neuronal activity might be spread over a range of frequencies as a result of the heterogeneous temporal nature of the neuronal activity, which is reflected in its frequency spectrum. Many studies have accounted for heterogeneous characteristics of the frequency of the signal by either directly inspecting the contents of frequency domain-transformed data or augmenting their analyses with such information. For example, studies on fMRI data have investigated brain functional connectivity by leveraging frequency-adjusted measures of dependence (e.g., when a correlation is measured as a function of frequency, as with "coherence"). Although these studies measure dependence as a function of frequency, the formulation does not capture all characteristics of the frequency-based dependence. Incorporating frequency information into a summarization approach would enable the retention of important frequency-related information that exists in the original space but might be lost after performing a frequency-independent summarization. We propose a novel data-driven approach built upon ICA, which is based on measuring dependence as a generalized function of frequency. Applying this approach to fMRI data provides evidence of existing cross-frequency functional connectivity between different areas of the brain.

PMID: 32317942 [PubMed]

Human Neural Stem Cell Induced Functional Network Stabilization After Cortical Stroke: A Longitudinal Resting-State fMRI Study in Mice.

Thu, 04/23/2020 - 12:40
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Human Neural Stem Cell Induced Functional Network Stabilization After Cortical Stroke: A Longitudinal Resting-State fMRI Study in Mice.

Front Cell Neurosci. 2020;14:86

Authors: Minassian A, Green C, Diedenhofen M, Vogel S, Hess S, Stoeber M, Radmilovic MD, Wiedermann D, Kloppenburg P, Hoehn M

Abstract
Most stroke studies dealing with functional deficits and assessing stem cell therapy produce extensive hemispheric damage and can be seen as a model for severe clinical strokes. However, mild strokes have a better prospect for functional recovery. Recently, anatomic and behavioral changes have been reported for distal occlusion of the middle cerebral artery (MCA), generating a well-circumscribed and small cortical lesion, which can thus be proposed as mild to moderate cortical stroke. Using this cortical stroke model of moderate severity in the nude mouse, we have studied the functional networks with resting-state functional magnetic resonance imaging (fMRI) for 12 weeks following stroke induction. Further, human neural stem cells (hNSCs) were implanted adjacent to the ischemic lesion, and the stable graft vitality was monitored with bioluminescence imaging (BLI). Differentiation of the grafted neural stem cells was analyzed by immunohistochemistry and by patch-clamp electrophysiology. Following stroke induction, we found a pronounced and continuously rising hypersynchronicity of the sensorimotor networks including both hemispheres, in contrast to the severe stroke filament model where profound reduction of the functional connectivity had been reported by us earlier. The vitality of grafted neural stem cells remained stable throughout the whole 12 weeks observation period. In the stem cell treated animals, functional connectivity did not show hypersynchronicity but was globally slightly reduced below baseline at 2 weeks post-stroke, normalizing thereafter completely. Our resting-state fMRI (rsfMRI) studies on cortical stroke reveal for the first time a hypersynchronicity of the functional brain networks. This hypersynchronicity appears as a hallmark of mild cortical strokes, in contrast to severe strokes with striatal involvement where exclusively hyposynchronicity has been reported. The effect of the stem cell graft was an early and persistent normalization of the functional sensorimotor networks across the whole brain. These novel functional results may help interpret future outcome investigations after stroke and demonstrate the highly promising potential of stem cell treatment for functional outcome improvement after stroke.

PMID: 32317940 [PubMed]

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