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A Pilot Study of Changes in Medial Temporal Lobe Fractional Amplitude of Low Frequency Fluctuations after Sildenafil Administration in Patients with Alzheimer's Disease.

Tue, 06/04/2019 - 20:33
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A Pilot Study of Changes in Medial Temporal Lobe Fractional Amplitude of Low Frequency Fluctuations after Sildenafil Administration in Patients with Alzheimer's Disease.

J Alzheimers Dis. 2019 May 25;:

Authors: Samudra N, Motes M, Lu H, Sheng M, Diaz-Arrastia R, Devous M, Hart J, Womack KB

Abstract
Alzheimer's disease (AD) is the most common cause of neurodegenerative cognitive impairment, defined by abnormal accumulations of amyloid-β and tau. Approaches directly targeting these proteins have not resulted in a disease modifying therapy. Neurovascular unit dysfunction is a feature of AD offering an alternative target for intervention. Sildenafil, a phosphodiesterase 5 (PDE5) inhibitor, improves cognitive functioning in mouse models of AD. Recent work in AD patients has demonstrated increased cerebral blood flow, as well as brain oxygen utilization after a single dose of sildenafil. Its effect on nitric oxide-cGMP signaling may have downstream effects on neuroplasticity, amyloid-β processing, and improved neurovascular unit function. Fractional amplitude of low frequency fluctuations (fALFF) assesses spontaneous neural activity via resting state fMRI BOLD signal (0.01-0.08 or 0.10 Hz). In AD, other assessments have revealed increased fALFF in hippocampi and parahippocampal gyri. Here, we examined the effects of a single dose of sildenafil on fALFF in a cohort of 10 AD patients. We found a decrease (p < 0.03, α= 0.05) in fALFF an hour after sildenafil administration in the right hippocampus. Additionally, cerebral vascular reactivity in response to carbon dioxide inhalation, a measure of neural vascular reserve previously collected on most of these participants, was not significantly correlated with this decrease, implying that change in fALFF may not have been solely due to altered vascular reactivity to CO2. We demonstrate that in patients with AD, hippocampal fALFF decreases in response to sildenafil, suggesting a normalization. These findings support further investigation into the effects of sildenafil in AD.

PMID: 31156166 [PubMed - as supplied by publisher]

Consciousness in a multilevel architecture: What causes the lateralization of effective connectivity under resting state?

Tue, 06/04/2019 - 20:33
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Consciousness in a multilevel architecture: What causes the lateralization of effective connectivity under resting state?

Conscious Cogn. 2019 May 30;73:102755

Authors: Velichkovsky BM, Ushakov VL, Sharaev MG

Abstract
Here we present our answers to a critical commentary by Elkhonon Goldberg on our recent publication (Velichkovsky et al., 2018). To avoid discussions about novelty effects in the human brain activity and memory processes, we narrowed down this response to a reanalysis of our data along the lines proposed in the commentary, namely to comparing the effective links between symmetrical brain structures during the first and the last parts of a prolonged resting-state fMRI experiment. We also tested for sex differences in our results and checked for a stability of top-down interactions during the course of experiment because learning is often expressed in the weakening of upper level control over low-level mechanisms. Our attempts to test the predictions based on the novelty hypothesis has led to mixed results suggesting that the discovered right-to-left dominance of causal connections at rest may have a deeper origin than supposed in the Goldberg's commentary.

PMID: 31154020 [PubMed - as supplied by publisher]

Resting-state connectivity alterations during transient global amnesia.

Tue, 06/04/2019 - 20:33
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Resting-state connectivity alterations during transient global amnesia.

Neuroimage Clin. 2019 May 23;23:101869

Authors: Zidda F, Griebe M, Ebert A, Ruttorf M, Roßmanith C, Gass A, Andoh J, Nees F, Szabo K

Abstract
While the pathophysiology of transient global amnesia (TGA) is not understood, due to the specific nature of the clinical deficits, transient dysfunction in the medial temporal lobe, especially in the hippocampus, is assumed; however, concomitant disturbances in other brain regions and in executive function have been postulated. In this study, a cohort of 16 patients was prospectively recruited from the emergency department for resting-state functional MRI (fMRI) during the acute stage of TGA, as confirmed by a standardized neuropsychological assessment. Twenty age- and sex-matched controls, as well as twenty patients with a history of TGA, were recruited for comparison. Functional data were processed using independent component analysis (ICA), allowing the complete automatic (data-driven) identification of spontaneous network dynamics. We documented a severe disturbance in anterograde episodic long-term memory in all patients. Group-based ICA of resting-state data in acute TGA patients versus that of controls and patients with a past TGA episode demonstrated reduced FC mainly of structures belonging to the executive network (EN), but also the hippocampus, confirming its pathophysiological involvement in the disorder, as well as areas belonging to the salience network and other subcortical regions. No significant differences were found when comparing connectivity in patients with a history of TGA and controls. Our findings strengthen previous empirical and theoretical accounts of hippocampal and executive dysfunction in TGA. The disruption of frontal, parietal and insular control regions, together with disruption in the hippocampus, provides a new interpretation for the pathophysiology and neuropsychological profile of this neurological disorder on a large-scale network level.

PMID: 31153000 [PubMed - as supplied by publisher]

Structural variability in the human brain reflects fine-grained functional architecture at the population level.

Tue, 06/04/2019 - 20:33
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Structural variability in the human brain reflects fine-grained functional architecture at the population level.

J Neurosci. 2019 May 31;:

Authors: Smith S, Duff E, Groves A, Nichols TE, Jbabdi S, Westlye LT, Tamnes CK, Engvig A, Walhovd KB, Fjell AM, Johansen-Berg H, Douaud G

Abstract
Human brain structure topography is thought to be related in part to functional specialisation. However, the extent of such relationships is unclear. Here, using a data-driven, multi-modal approach for studying brain structure across the lifespan (n=484, 260 females), we demonstrate that numerous structural networks, covering the entire brain, follow a functionally-meaningful architecture. These grey matter networks emerge from the co-variation of grey matter volume and cortical area at the population level. We further reveal fine-grained anatomical signatures of functional connectivity. For example, within the cerebellum, a structural separation emerges between lobules that are functionally connected to distinct, mainly sensorimotor, cognitive and limbic regions of the cerebral cortex and subcortex. Structural modes of variation also replicate the fine-grained functional architecture seen in 8 well-defined visual areas in both task and resting-state fMRI. Furthermore, our study shows a structural distinction corresponding to the established segregation between anterior and posterior default-mode networks. These fine-grained grey matter networks further cluster together to form functionally-meaningful larger-scale organisation. In particular, we identify a structural architecture bringing together the functional posterior default-mode network and its anti-correlated counterpart. In summary, our results demonstrate that the relationship between structural and functional connectivity is fine-grained, widespread across the entire brain, and driven by co-variation in cortical area, i.e. likely differences in shape, depth or number of foldings. These results suggest that neurotrophic events occur during development to dictate that the size and folding pattern of distant, functionally-connected brain regions should vary together across subjects.SIGNIFICANCE STATEMENTQuestions over the relationship between structure and function in the human brain have engaged neuroscientists for centuries in a debate that continues to this day. Here, by interrogating inter-subject variation in brain structure across a large number of individuals, we reveal modes of structural variation that map onto fine-grained functional organisation across the entire brain, and specifically in the cerebellum, visual areas and default-mode network. This functionally-meaningful structural architecture emerges from the co-variation of grey matter volume and cortical folding. These results suggest that the neurotrophic events at play during development, and possibly evolution, which dictate that the size and folding pattern of distant brain regions should vary together across subjects, might also play a role in functional cortical specialisation.

PMID: 31152123 [PubMed - as supplied by publisher]

Multivariate graph learning for detecting aberrant connectivity of dynamic brain networks in autism.

Mon, 06/03/2019 - 23:32
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Multivariate graph learning for detecting aberrant connectivity of dynamic brain networks in autism.

Med Image Anal. 2019 May 25;56:11-25

Authors: Aggarwal P, Gupta A

Abstract
Alterations in static functional brain networks have previously been reported in Autistic Spectrum Disorder (ASD). Although functional brain networks are known to be time-varying, alterations in time-varying or dynamic brain networks in ASD is largely unknown. Hence, in this study, we analyze resting-state fMRI data of ASD group versus Typically Developing Control (TDC) group to understand alterations in dynamic functional brain networks in ASD vis-à-vis healthy controls. We introduce a new framework for extracting overlapping dynamic functional brain networks to study these alterations. We utilize sliding window approach along with the recent Multivariate Vector Regression-based Connectivity (MVRC) method to construct functional connectivity (FC) matrices in each time-window. Further, we build three-mode subject-summarized spatio-temporal tensor in both ASD and TDC groups. This tensor is utilized to determine a set of overlapping dynamic functional brain networks and their temporal profiles. This helps us in studying alterations in dynamic brain networks in ASD subjects at the group-level. The proposed framework is tested on two publicly available resting-state fMRI dataset of ASD and normal controls. Our analyses on resting-state fMRI data indicate that dynamic functional brain networks of ASD subjects are altered compared to the TDC group. Two-sample t-test is used to establish the statistical significance of the differences observed in network strengths of the two groups. Compared to the TDC subjects, autistic subjects showed alterations in multiple functional brain networks including cognitive control, subcortical, auditory, visual, bilateral limbic, and default mode network. The proposed methodology is able to provide information on alterations in dynamic functional brain networks in ASD and may provide potential biomarkers for studying human brain disorders.

PMID: 31150935 [PubMed - as supplied by publisher]

Abnormal Brain Functional Connectivity strength in the overactive bladder syndrome: A Resting-State fMRI Study.

Mon, 06/03/2019 - 23:32
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Abnormal Brain Functional Connectivity strength in the overactive bladder syndrome: A Resting-State fMRI Study.

Urology. 2019 May 28;:

Authors: Zuo L, Zhou Y, Wang S, Wang B, Gu H, Chen J

Abstract
OBJECTIVE: To investigate the whole-brain functional connectivity strength (FCS) of patients with the overactive bladder syndrome (OAB).
METHODS: This study investigates the changes of intrinsic whole brain functional connectivity pattern in OAB using FCS. We acquired resting-state fMRI data from twenty-six OAB patients and twenty-eight healthy controls. FCS was used to compute the long-range and short-range FCS values for each voxel in the brain of each subject. The long or short-range FCS maps were compared between OAB patients and healthy controls. Pearson's correlation coefficients was also performed between abnormal FCS regions and clinical/psychometric scores in patients.
RESULTS: Compared with healthy control subjects, the OAB patients exhibited significantly decreased short-range FCS in the right medial superior frontal gyrus and bilateral anterior cingulate gyrus, and increased short-range FCS in the middle frontal gyrus, the precentral gyrus, and bilateral caudate nucleus. In addition, significantly decreased long-range FCS was found in bilateral middle cingulate gyrus and posterior cingulate gyrus. Furthermore, the abnormal FCS values in the right caudate nucleus showed significantly negative correlation with self-rating depression scale of OAB patients.
CONCLUSION: Patients with OAB have abnormal short-range and long-range FCS in brain regions associated with brain-bladder network. Our study provides new insights into the underlying brain network topology of OAB.

PMID: 31150692 [PubMed - as supplied by publisher]

Abnormal Functional Relationship of Sensorimotor Network With Neurotransmitter-Related Nuclei via Subcortical-Cortical Loops in Manic and Depressive Phases of Bipolar Disorder.

Mon, 06/03/2019 - 23:32
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Abnormal Functional Relationship of Sensorimotor Network With Neurotransmitter-Related Nuclei via Subcortical-Cortical Loops in Manic and Depressive Phases of Bipolar Disorder.

Schizophr Bull. 2019 May 31;:

Authors: Martino M, Magioncalda P, Conio B, Capobianco L, Russo D, Adavastro G, Tumati S, Tan Z, Lee HC, Lane TJ, Amore M, Inglese M, Northoff G

Abstract
OBJECTIVE: Manic and depressive phases of bipolar disorder (BD) show opposite psychomotor symptoms. Neuronally, these may depend on altered relationships between sensorimotor network (SMN) and subcortical structures. The study aimed to investigate the functional relationships of SMN with substantia nigra (SN) and raphe nuclei (RN) via subcortical-cortical loops, and their alteration in bipolar mania and depression, as characterized by psychomotor excitation and inhibition.
METHOD: In this resting-state functional magnetic resonance imaging (fMRI) study on healthy (n = 67) and BD patients (n = 100), (1) functional connectivity (FC) between thalamus and SMN was calculated and correlated with FC from SN or RN to basal ganglia (BG)/thalamus in healthy; (2) using an a-priori-driven approach, thalamus-SMN FC, SN-BG/thalamus FC, and RN-BG/thalamus FC were compared between healthy and BD, focusing on manic (n = 34) and inhibited depressed (n = 21) patients.
RESULTS: (1) In healthy, the thalamus-SMN FC showed a quadratic correlation with SN-BG/thalamus FC and a linear negative correlation with RN-BG/thalamus FC. Accordingly, the SN-related FC appears to enable the thalamus-SMN coupling, while the RN-related FC affects it favoring anti-correlation. (2) In BD, mania showed an increase in thalamus-SMN FC toward positive values (ie, thalamus-SMN abnormal coupling) paralleled by reduction of RN-BG/thalamus FC. By contrast, inhibited depression showed a decrease in thalamus-SMN FC toward around-zero values (ie, thalamus-SMN disconnection) paralleled by reduction of SN-BG/thalamus FC (and RN-BG/thalamus FC). The results were replicated in independent HC and BD datasets.
CONCLUSIONS: These findings suggest an abnormal relationship of SMN with neurotransmitters-related areas via subcortical-cortical loops in mania and inhibited depression, finally resulting in psychomotor alterations.

PMID: 31150559 [PubMed - as supplied by publisher]

Intrinsic Connectivity of the Globus Pallidus: An Uncharted Marker of Functional Prognosis in People With First-Episode Schizophrenia.

Mon, 06/03/2019 - 23:32
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Intrinsic Connectivity of the Globus Pallidus: An Uncharted Marker of Functional Prognosis in People With First-Episode Schizophrenia.

Schizophr Bull. 2019 May 31;:

Authors: Tarcijonas G, Foran W, Haas GL, Luna B, Sarpal DK

Abstract
There is growing evidence suggesting that abnormalities in cortical-basal ganglia circuitry may play a significant role in determining outcomes in schizophrenia. The globus pallidus (GP), a critical structure within this circuitry, unique in its role as a mediator of competing inputs through the striatum, has not been well characterized in schizophrenia. The following study examined functional interactions of the GP in individuals with first-episode schizophrenia (FES). To probe the large-scale intrinsic connectivity of the GP, resting-state fMRI scans were obtained from patients with FES and sex and age-matched healthy controls. Participants with FES were also evaluated after 6 months via the Strauss-Carpenter Outcomes Scale to assess overall functional trajectory. The GP was parcellated to generate seeds within its substructures, and connectivity maps were generated. Our FES cohort showed significantly lower functional connectivity between the left GP interna and a network of regions including the dorsolateral prefrontal cortex, caudate, and cerebellum at baseline. In addition, FES participants with lower overall scores of functioning at 6 months showed significantly decreased connectivity between the GP interna and the dorsal anterior cingulate and bilateral insula, all regions important for motivational salience. These results provide novel evidence for unique abnormalities in functional interactions of the GP with key prefrontal cortical regions in FES. Our findings also suggest that reduced prefrontal-pallidal connectivity may serve as a predictor of early functional outcome.

PMID: 31150557 [PubMed - as supplied by publisher]

Intranasal oxytocin alters amygdala-temporal resting-state functional connectivity in body dysmorphic disorder: A double-blind placebo-controlled randomized trial.

Sat, 06/01/2019 - 02:29
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Intranasal oxytocin alters amygdala-temporal resting-state functional connectivity in body dysmorphic disorder: A double-blind placebo-controlled randomized trial.

Psychoneuroendocrinology. 2019 May 22;107:179-186

Authors: Grace SA, Labuschagne I, Castle DJ, Rossell SL

Abstract
The aetiology of body dysmorphic disorder (BDD) is poorly understood. Recent evidence from functional brain imaging studies suggests that BDD is associated with aberrant task-based functional connectivity and that intranasal oxytocin (OXT) may improve network connectivity in BDD patients. Thus, the aim of this study was to investigate the effect of intranasal OXT on amygdala resting-state functional connectivity (rsFC) in BDD. In a randomized, double-blind, cross-over design, 19 BDD participants and 17 demographically matched healthy control participants received intranasal OXT (24 IU) or placebo prior to resting-state functional magnetic resonance imaging. The left and right amygdala were seeded as regions of interest, and temporal correlations between the amygdalae and all other voxels comprising cortical and subcortical grey matter were investigated. Compared to healthy controls, BDD patients showed greater baseline (placebo) rsFC between the left amygdala and two clusters within the left temporal lobe and one cluster within the superior frontal gyrus which was reversed following OXT administration. The control group also showed significantly greater rsFC between the left amygdala and anterior prefrontal cortex in the OXT session compared to placebo. Whilst preliminary, these findings suggest that BDD patients exhibit abnormal amygdala-temporal connectivity at rest, and OXT might have a role in changing this functional relationship.

PMID: 31146138 [PubMed - as supplied by publisher]

Default mode dysfunction underpins suicidal activity in mood disorders.

Sat, 06/01/2019 - 02:29
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Default mode dysfunction underpins suicidal activity in mood disorders.

Psychol Med. 2019 May 30;:1-10

Authors: Malhi GS, Das P, Outhred T, Bryant RA, Calhoun V, Mann JJ

Abstract
BACKGROUND: Suicide is a serious and not uncommon consequence of mood disorders that occurs primarily when individuals are depressed. Understanding the neurobiology of suicidal activity (thoughts or behaviors) is likely to facilitate prevention.
METHOD: Seventy-nine adult depressed mood disorder patients (MDP), of which 25 had attempted suicide at least once, and 66 healthy controls (HC) participated in this study. Resting-state functional MRI was used to identify neural activity differences between suicide attempters (SA) and non-attempters (NA). Specifically, differences were examined in functional connectivity both within and between four large cognitive networks [Executive Control (ECN), Default Mode (DMN), Salience (SN), and Basal Ganglia (BGN)] and their respective associations with suicidal activity.
RESULTS: Compared to HCs, patients had greater posterior DMN activity, but less activity in the BGN, and less low-frequency spectral power in the dorso-medial DMN. Furthermore, increased posterior DMN activity in SA was associated with recent suicidal activity, whereas NA had reduced BGN activity and less dorso-medial DMN spectral power, the latter being associated with lifelong suicidal thinking. SA also had greater activity in midline circuitry compared to both HC and NA, and the pattern of BGN and DMN co-activity differed between SA and NA.
CONCLUSIONS: DMN engagement raises the possibility that suicidal activity in mood disorder patients may be a consequence of impaired self-referential thought processing. Furthermore, differential BGN and DMN co-activation according to suicide attempt status suggests that attempting suicide perhaps alters cognitive flexibility. These insights are potentially useful for understanding the neural basis of suicide activity.

PMID: 31144614 [PubMed - as supplied by publisher]

Structural and functional MRI correlates of T2 hyperintensities of brain white matter in young neurologically asymptomatic adults.

Sat, 06/01/2019 - 02:29
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Structural and functional MRI correlates of T2 hyperintensities of brain white matter in young neurologically asymptomatic adults.

Eur Radiol. 2019 May 29;:

Authors: Keřkovský M, Stulík J, Dostál M, Kuhn M, Lošák J, Praksová P, Hulová M, Bednařík J, Šprláková-Puková A, Mechl M

Abstract
OBJECTIVES: Although white matter hyperintensities (WMHs) are quite commonly found incidentally, their aetiology, structural characteristics, and functional consequences are not entirely known. The purpose of this study was to quantify WMHs in a sample of young, neurologically asymptomatic adults and evaluate the structural and functional correlations of lesion load with changes in brain volume, diffusivity, and functional connectivity.
METHODS: MRI brain scan using multimodal protocol was performed in 60 neurologically asymptomatic volunteers (21 men, 39 women, mean age 34.5 years). WMHs were manually segmented in 3D FLAIR images and counted automatically. The number and volume of WMHs were correlated with brain volume, resting-state functional MRI (rs-fMRI), and diffusion tensor imaging (DTI) data. Diffusion parameters measured within WMHs and normally appearing white matter (NAWM) were compared.
RESULTS: At least 1 lesion was found in 40 (67%) subjects, median incidence was 1 lesion (interquartile range [IQR] = 4.5), and median volume was 86.82 (IQR = 227.23) mm3. Neither number nor volume of WMHs correlated significantly with total brain volume or volumes of white and grey matter. Mean diffusivity values within WMHs were significantly higher compared with those for NAWM, but none of the diffusion parameters of NAWM were significantly correlated with WMH load. Both the number and volume of WMHs were correlated with the changes of functional connectivity between several regions of the brain, mostly decreased connectivity of the cerebellum.
CONCLUSIONS: WMHs are commonly found even in young, neurologically asymptomatic adults. Their presence is not associated with brain atrophy or global changes of diffusivity, but the increasing number and volume of these lesions correlate with changes of brain connectivity, and especially that of the cerebellum.
KEY POINTS: • White matter hyperintensities (WMHs) are commonly found in young, neurologically asymptomatic adults. • The presence of WMHs is not associated with brain atrophy or global changes of white matter diffusivity. • The increasing number and volume of WMHs correlate with changes of brain connectivity, and especially with that of the cerebellum.

PMID: 31144071 [PubMed - as supplied by publisher]

Altered functional connectivity density in primary angle-closure glaucoma patients at resting-state.

Sat, 06/01/2019 - 02:29
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Altered functional connectivity density in primary angle-closure glaucoma patients at resting-state.

Quant Imaging Med Surg. 2019 Apr;9(4):603-614

Authors: Chen L, Li S, Cai F, Wu L, Gong H, Pei C, Zhou F, Zeng X

Abstract
Background: Primary angle-closure glaucoma (PACG) is a neurodegenerative disease. Previous structural and functional studies of functional magnetic resonance imaging (fMRI) have demonstrated widespread dysfunction of spontaneous activity in the PACG brain. In this study, we applied a data-driven graph theory approach of functional connectivity density (FCD) mapping to investigate the altered local and global functional connectivity (FC) of the cortex in PACG.
Methods: Forty-five PACG patients (53.28±10.79 years, 17 males/28 females) and 46 well-matched healthy controls (HCs) (52.67±11.01 years,18 males/28 females) received resting-state fMRI scans. All PACG patients finished complete ophthalmologic examinations, including retinal nerve fiber layer thickness (RNFLT), intraocular pressure (IOP), average cup to disc ratio (A-C/D), and vertical cup to disc ratio (V-C/D). We calculated the between-group FCD difference for short-range and long-range in each voxel. Then, we generated the intrinsic FC of the seed region with the whole brain. Finally, correlations were investigated between FCD value of the altered regions and clinical variables.
Results: PACG patients showed increased short-range FCD in the left inferior frontal gyrus (IFG)/insula/parahippocampal gyrus and right IFG/insula (P<0.05, corrected), compared with the HCs. Simultaneously, the decreased regions in short-range FCD map were the occipital/cuneus/precuneus/superior parietal/postcentral lobe (P<0.05, corrected). In the PACG groups, decreased long-range FCD was observed in the left middle frontal gyrus compared to the HC (P<0.05, corrected). RNFLT was positively correlated with decreased short-range FCD value of the occipital/cuneus/precuneus/superior parietal/postcentral lobes, and the A-C/D was negatively correlated with the increased short-range FCD value of the left IFG/insula/parahippocampal gyrus, and the right IFG/insula.
Conclusions: Our findings suggest that PACG can induce extensive brain dysfunction, and showed different spatial distribution in short- and long-range FCD.

PMID: 31143651 [PubMed]

Effect of cervical manipulation on vertebral artery and cerebral haemodynamics in patients with chronic neck pain: a crossover randomised controlled trial.

Sat, 06/01/2019 - 02:29
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Effect of cervical manipulation on vertebral artery and cerebral haemodynamics in patients with chronic neck pain: a crossover randomised controlled trial.

BMJ Open. 2019 May 28;9(5):e025219

Authors: Moser N, Mior S, Noseworthy M, Côté P, Wells G, Behr M, Triano J

Abstract
OBJECTIVE: It is hypothesised that cervical manipulation may increase the risk of cerebrovascular accidents. We aimed to determine whether cervical spine manipulation is associated with changes in vertebral artery and cerebrovascular haemodynamics measured with MRI compared with neutral neck position and maximum neck rotation in patients with chronic neck pain.
SETTING: The Imaging Research Centre at St. Joseph's Hospital in Hamilton, Ontario, Canada.
PARTICIPANTS: Twenty patients were included. The mean age was 32 years (SD ±12.5), mean neck pain duration was 5.3 years (SD ±5.7) and mean neck disability index score was 13/50 (SD ±6.4).
INTERVENTIONS: Following baseline measurement of cerebrovascular haemodynamics, we randomised participants to: (1) maximal neck rotation followed by cervical manipulation or (2) cervical manipulation followed by maximal neck rotation. The primary outcome, vertebral arteries and cerebral haemodynamics, was measured after each intervention and was obtained by measuring three-dimensional T1-weighted high-resolution anatomical images, arterial spin labelling and phase-contrast flow encoded MRI. Our secondary outcome was functional connectivity within the default mode network measured with resting state functional MRI.
RESULTS: Compared with neutral neck position, we found a significant change in contralateral blood flow following maximal neck rotation. There was also a significant change in contralateral vertebral artery blood velocity following maximal neck rotation and cervical manipulation. We found no significant changes within the cerebral haemodynamics following cervical manipulation or maximal neck rotation. However, we observed significant increases in functional connectivity in the posterior cerebrum and cerebellum (resting state MRI) after manipulation and maximum rotation.
CONCLUSION: Our results are in accordance with previous work, which has shown a decrease in blood flow and velocity in the contralateral vertebral artery with head rotation. This may explain why we also observed a decrease in blood velocity with manipulation because it involves neck rotation. Our work is the first to show that cervical manipulation does not result in brain perfusion changes compared with a neutral neck position or maximal neck rotation. The changes observed were found to not be clinically meaningful and suggests that cervical manipulation may not increase the risk of cerebrovascular events through a haemodynamic mechanism.
TRIAL REGISTRATION NUMBER: NCT02667821.

PMID: 31142519 [PubMed - in process]

Functional connectivity of language networks after perinatal stroke.

Thu, 05/30/2019 - 20:28
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Functional connectivity of language networks after perinatal stroke.

Neuroimage Clin. 2019 May 21;23:101861

Authors: Carlson HL, Sugden C, Brooks BL, Kirton A

Abstract
Successful language acquisition during development is imperative for lifelong function. Complex language networks develop throughout childhood. Perinatal stroke may cause significant language disabilities but function can also be remarkably normal. Studying such very early brain injury populations may inform developmental plasticity models of language networks. We examined functional connectivity (FC) of language networks in children with arterial and venous perinatal stroke and typically developing controls (TDC) in a population-based, controlled, cohort study. Resting state functional MRI was performed at 3 T (TR/TE = 2000/30 ms, 150 volumes, 3.6mm3 voxels). Seed-based analyses used bilateral inferior frontal and superior temporal gyri. A subset of stroke participants completed clinical language testing. Sixty-six children participated (median age: 12.85±3.8y, range 6-19; arterial N = 17; venous N = 15; TDC N = 34]. Children with left hemisphere strokes had comparable FC in their right hemispheres compared to TDC. Inter- and intra-hemispheric connectivity strengths were similar between TDC and PVI but lower for AIS. Reduced FC was associated with poorer language comprehension. Language networks can be estimated using resting-state fMRI in children with perinatal stroke. Altered connectivity may occur in both hemispheres, is more pronounced with arterial lesions, and is associated with clinical function. Our results have implications for therapeutic language interventions after early stroke.

PMID: 31141787 [PubMed - as supplied by publisher]

Abnormal functional network of the thalamic subregions in adult patients with obsessive-compulsive disorder.

Thu, 05/30/2019 - 20:28
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Abnormal functional network of the thalamic subregions in adult patients with obsessive-compulsive disorder.

Behav Brain Res. 2019 May 26;:111982

Authors: Li K, Zhang H, Yang Y, Zhu J, Wang B, Shi Y, Li X, Meng Z, Lv L, Zhang H

Abstract
The thalamus plays an important role in pathological mechanisms underlying obsessive-compulsive disorder (OCD). As the thalamus is a heterogeneous brain region, functional connectivity (FC) between thalamic subregions and other brain regions is worth investigating in OCD. In addition, the relationship between abnormal FC and clinical symptoms is still unclear. In this study, we used resting-state functional magnetic resonance imaging to scan 45 OCD patients and 43 well-matched healthy controls (HCs). Thalamic subregions were defined according to the Human Brainnetome Atlas. The fractional amplitude of low-frequency fluctuations (fALFF) and FC seeding-based connectivity were compared using a two-sample t-test. Correlations between abnormal FC and clinical symptoms were analyzed in OCD patients. Compared with HCs, increased fALFF was found in the bilateral thalamus, and increased FC was observed between the right posterior parietal thalamus (PPtha) and left middle occipital gyrus (LMOG) and between the right occipital thalamus (Otha) and right middle occipital gyrus (RMOG) in OCD patients. In addition, OCD patients had reduced FC between the left sensory thalamus (Stha) and left orbital inferior frontal gyrus, right PPtha and left prefrontal cortex, and between the right Otha and left inferior parietal gyrus (LIPG), respectively. Within the OCD group, the FC between right PPtha-LMOG was correlated with severity of clinical symptoms. These results revealed that the FC between the thalamus and occipital is related to obsessive-compulsive symptoms in OCD patients. This finding provides more accurate information about the involvement of the thalamus in the pathophysiology of OCD.

PMID: 31141727 [PubMed - as supplied by publisher]

Altered amplitude of low-frequency fluctuation in basal ganglia correlates to pulmonary ventilation function in COPD patients: A resting-state fMRI study.

Thu, 05/30/2019 - 20:28
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Altered amplitude of low-frequency fluctuation in basal ganglia correlates to pulmonary ventilation function in COPD patients: A resting-state fMRI study.

Brain Behav. 2019 May 29;:e01336

Authors: Lu CQ, Xu W, Zeng CH, Ge LY, Wang YC, Meng XP, Yu Q, Wu D, Ju S

Abstract
INTRODUCTION: Patients under chronic obstructive pulmonary disease (COPD) has been reported to be associated with a higher prevalence of cognitive impairment (CI). However, it is still largely unknown whether the aberrant resting-state spontaneous neuronal activity pattern reflected by the amplitude of low-frequency fluctuation (ALFF) analysis will be associated with the CI in COPD patients.
MATERIALS: A total of 28 COPD patients and 26 healthy controls were enrolled in this study. Of all the subjects, structural and functional MRI data, spirometry tests performance and neuropsychological assessments of different cognitive domains were collected. Voxel-based two-sample t tests were used to detect brain regions showing differences in the ALFF value between COPD patients and healthy controls. An additional fMRI runs with supplementary oxygen delivery were employed to explore the impact of elevated partial pressure of oxygen (PaO2 ) or moderate hyperoxia on ALFF in COPD patients and healthy controls respectively.
RESULTS: More extensive white matter lesion was detected in COPD patients. COPD patients exhibit decreased ALFF value in bilateral basal ganglia areas and right thalamus, and aberrant ALFF value is correlated with PaO2 and pulmonary ventilation function (FEV1%pred). COPD patients performed worse in the Digit Span Test (reverse), Digit Symbol Substitution Test, Trail-making test (A and B) than controls. After supplementary oxygen inhalation, the ALFF value of basal ganglia and right thalamus significantly increased in the controls, but not in the COPD patients.
CONCLUSIONS: COPD patients mainly exhibit impaired executive function but not long-term memory in cognitive function assessment. Aberrant ALFF alteration in the deep brain may be directly related to lower PaO2 in COPD patients.

PMID: 31140760 [PubMed - as supplied by publisher]

Relating brain connectivity with persistent symptoms in pediatric concussion.

Thu, 05/30/2019 - 20:28
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Relating brain connectivity with persistent symptoms in pediatric concussion.

Ann Clin Transl Neurol. 2019 May;6(5):954-961

Authors: Iyer KK, Barlow KM, Brooks B, Ofoghi Z, Zalesky A, Cocchi L

Abstract
Persistent post-concussion symptoms (PCS) in children following a mild traumatic brain injury (mTBI) are a growing public health concern. There is a pressing need to understand the neural underpinning of PCS. Here, we examined whole-brain functional connectivity from resting-state fMRI with behavioral assessments in a cohort of 110 children with mTBI. Children with mTBI and controls had similar levels of connectivity. PCS symptoms and behaviors including poor cognition and sleep were associated with connectivity within functional brain networks. The identification of a single "positive-negative" dimension linking connectivity with behaviors enables better prognosis and stratification toward personalized therapeutic interventions.

PMID: 31139693 [PubMed]

Music in premature infants enhances high-level cognitive brain networks.

Thu, 05/30/2019 - 20:28
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Music in premature infants enhances high-level cognitive brain networks.

Proc Natl Acad Sci U S A. 2019 May 28;:

Authors: Lordier L, Meskaldji DE, Grouiller F, Pittet MP, Vollenweider A, Vasung L, Borradori-Tolsa C, Lazeyras F, Grandjean D, Van De Ville D, Hüppi PS

Abstract
Neonatal intensive care units are willing to apply environmental enrichment via music for preterm newborns. However, no evidence of an effect of music on preterm brain development has been reported to date. Using resting-state fMRI, we characterized a circuitry of interest consisting of three network modules interconnected by the salience network that displays reduced network coupling in preterm compared with full-term newborns. Interestingly, preterm infants exposed to music in the neonatal intensive care units have significantly increased coupling between brain networks previously shown to be decreased in premature infants: the salience network with the superior frontal, auditory, and sensorimotor networks, and the salience network with the thalamus and precuneus networks. Therefore, music exposure leads to functional brain architectures that are more similar to those of full-term newborns, providing evidence for a beneficial effect of music on the preterm brain.

PMID: 31138687 [PubMed - as supplied by publisher]

[A preliminary study on resting-state functional magnetic resonance imaging of brain after anterior cruciate ligament preservation reconstruction with autologous tendon].

Thu, 05/30/2019 - 20:28
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[A preliminary study on resting-state functional magnetic resonance imaging of brain after anterior cruciate ligament preservation reconstruction with autologous tendon].

Zhonghua Yi Xue Za Zhi. 2019 May 21;99(19):1479-1483

Authors: Wang JQ, Liu H, Wang XB, Zhang YQ, Wang SQ, Shi YQ, Zhang M, Zhao XH

Abstract
Objective: To preliminarily study on the possible mechanism of cerebral cortical dysfunction pattern after anterior cruciate ligament (ACL) preservation reconstruction with autologous tendon through resting-state functional magnetic resonance imaging (fMRI). Methods: From June 2015 to February 2019, 18 patients (10 males and 8 females with an average age of (36±10) years) with left anterior cruciate ligament rupture and treated with arthroscopic preservation reconstruction with autologous tendon were enrolled in this study, and 17 comparable healthy controls were included in Tongji Hospital of Tongji University. fMRI was performed after the postoperative period (2 to 12 weeks). The fMRI data were preprocessed by SPM8 software package and RESTplus software. The amplitude of low-frequency fluctuation (ALFF) and the fractional amplitude of low-frequency fluctuation (fALFF) in those two groups were calculated. Two-sample t-test was performed on ALFF and fALFF of the two groups, and multiple test corrections were performed by using AlphaSim. These methods were used for contrast studies on the characteristic activities of the brain dysfunction. Results: Compared with those in the control, ALFF in the central cingulate gyrus (cingulum_mid_bilateral), involving the auxiliary movement zone (supp_motor_ area) were significantly higher in the patients (P<0.01 before correction, P<0.05 after AlphaSim correction). The fALFF in activation cluster 1 was significantly higher in the right central gyrus (postcentral_R), the right lower lobule (parietal_inf_R), and the right upper margin (supramarginal_R) in the patients than that in the normal control group, respectively (P<0.01 before correction, P<0.05 after AlphaSim correction); the fALFF in activation cluster 2 in the right central cingulate gyrus (cingulum_mid_R), involving the right auxiliary movement zone (supp_motor_area_R) was significantly higher in the patients than that in the normal control group, respectively (P<0.01 before correction, P<0.05 after AlphaSim correction). Conclusion: The patients' cerebrum cortical function associated with the kinesthesis and their regulations are abnormally changed after anterior cruciate ligament preservation reconstruction with autologous tendon.

PMID: 31137138 [PubMed - in process]

Language as a Threat: Multimodal Evaluation and Interventions for Overwhelming Linguistic Anxiety in Severe Aphasia.

Wed, 05/29/2019 - 05:27
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Language as a Threat: Multimodal Evaluation and Interventions for Overwhelming Linguistic Anxiety in Severe Aphasia.

Front Psychol. 2019;10:678

Authors: Torres-Prioris MJ, López-Barroso D, Paredes-Pacheco J, Roé-Vellvé N, Dawid-Milner MS, Berthier ML

Abstract
Linguistic anxiety (LA) is an abnormal stress response induced by situations that require the use of verbal behavior, and it is accentuated during language testing in persons with aphasia (PWA). The presence of LA in PWA may jeopardize the interpretation of cognitive evaluations, leading to biased conclusions about the severity of the language alteration and the effectiveness of the treatments. In the present study, we report the case of a woman (Mrs. A) with severe chronic mixed transcortical aphasia due to left frontal and parietal hemorrhages that partially spared the perisylvian area. Mrs. A was treated with the dopamine agonist Rotigotine alone and combined with Intensive Language-Action Therapy (ILAT). Complementary evaluations included autonomic reactivity during the performance of different language tasks, resting state functional magnetic resonance imaging (rs-fMRI) and [18F]-fluorodeoxyglucose positron emission tomography (18F-FDG-PET). We found that formal language testing in a clinical setting triggered a dramatic increase of automatic echolalia, perseverations and frustration, making the task completion difficult. The treatment improved aphasia, but gains were more robust when evaluation was performed by Mrs. A's husband at home than by clinicians. Autonomic evaluation under Rotigotine revealed higher reactivity during tasks tapping an impaired function in comparison with a task evaluating a preserved function (verbal repetition). Baseline 18F-FDG-PET analysis showed decreased metabolic activity in left limbic-paralimbic areas, whereas rs-fMRI revealed compensatory activity in the right hemisphere. We also analyzed the different factors (e.g., premorbid personality traits, task difficulty) that may have contributed to LA in Mrs. A during language testing. Our findings emphasize the usefulness of implicating adequately trained laypersons in the evaluation and treatment of PWA showing LA. Further studies using multidimensional evaluations are needed to disentangle the interplay between anxiety and abnormal language as well as the neural mechanisms underpinning LA in PWA.

PMID: 31133908 [PubMed]