New resting-state fMRI related studies at PubMed

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Aberrant functional connectivity of neural circuits associated with social and sensorimotor deficits in young children with autism spectrum disorder.

Tue, 11/27/2018 - 12:00

Aberrant functional connectivity of neural circuits associated with social and sensorimotor deficits in young children with autism spectrum disorder.

Autism Res. 2018 Nov 26;:

Authors: Chen H, Wang J, Uddin LQ, Wang X, Guo X, Lu F, Duan X, Wu L, Chen H

Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by atypical functional integration of brain regions. The vast majority of neuroimaging studies of ASD have focused on older children, adolescents, and adults with the disorder. Very little work has explored whole-brain functional connectivity of young children with ASD. Here, we collected resting-state functional magnetic resonance imaging data from 58 young children (mean age 4.98 years; 29 with ASD; 29 matched healthy controls [HC]). All children were under sedation during scanning. A functional "connectedness" method was first used to seek for brain regions showing atypical functional connectivity (FC) in children with ASD. Then, a recurrent-seek strategy was applied to reveal atypical FC circuits in ASD children. FC matrices between regions-of-interest (ROIs) were compared between ASD and HC. Finally, a support vector regression (SVR) method was used to assess the relationship between the FC circuits and ASD symptom severity. Two atypical FC circuits comprising 23 ROIs in ASD were revealed: one predominantly comprised brain regions involved with social cognition showing under-connectivity in ASD; the other predominantly comprised sensory-motor and visual brain regions showing over-connectivity in ASD. The SVR analysis showed that the two FC circuits were separately related to social deficits and restricted behavior scores. These findings indicate disrupted FC of neural circuits involved in the social and sensorimotor processes in young children with ASD. The finding of the atypical FC patterns in young children with ASD underscores the utility of studying younger children with the disorder, and highlights nuanced patterns of brain connectivity underlying behavior closer to disorder onset. Autism Res 2018. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Autism spectrum disorder (ASD) is an early-onset neurodevelopmental disorder. Understanding brain functional alterations at early ages is important for understanding biological mechanisms of ASD. Here, we found two atypical brain functional circuits in young children with ASD that were related to social and sensorimotor function. These results show how atypical patterns of brain functional connectivity in young children with of ASD may underlie core symptoms of the disorder.

PMID: 30475453 [PubMed - as supplied by publisher]

Resting-state brain activity in Chinese boys with low functioning autism spectrum disorder.

Tue, 11/27/2018 - 12:00
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Resting-state brain activity in Chinese boys with low functioning autism spectrum disorder.

Ann Gen Psychiatry. 2018;17:47

Authors: Li G, Rossbach K, Jiang W, Du Y

Abstract
Background: This study aimed to explore the resting-state fMRI changes in Chinese boys with low functioning autism spectrum disorder (LFASD) and the correlation with clinical symptoms.
Methods: The current study acquired resting-state fMRI data from 15 Chinese boys with LFASD and 15 typically developing (TD) boys to examine the local brain activity using the regional homogeneity (ReHo) and amplitude of low-frequency fluctuation (ALFF) indexes; the researchers also examined these measures and their possible relationships with clinical symptoms using the autism behavior checklist.
Results: Results indicated that boys with LFASD exhibited increased ReHo in the right precuneus and inferior parietal gyrus (IPG), increased ALFF in right middle temporal gyrus, angular gyrus and IPG. However, no correlation was found between the ALFF/ReHo score and clinical symptoms in the LFASD group.
Conclusions: Some of the brain regions had ReHo/ALFF values that were higher in the boys with LFASD than the TD group and these differentiated brain areas in boys with LFASD were all on the right cerebrum, which supported 'atypical rightward asymmetry' in boys with LFASD.

PMID: 30473720 [PubMed]

Increased cognitive complexity reveals abnormal brain network activity in individuals with corpus callosum dysgenesis.

Tue, 11/27/2018 - 12:00
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Increased cognitive complexity reveals abnormal brain network activity in individuals with corpus callosum dysgenesis.

Neuroimage Clin. 2018 Nov 14;:

Authors: Hearne LJ, Dean RJ, Robinson GA, Richards LJ, Mattingley JB, Cocchi L

Abstract
Cognitive reasoning is thought to require functional interactions between whole-brain networks. Such networks rely on both cerebral hemispheres, with the corpus callosum providing cross-hemispheric communication. Here we used high-field functional magnetic resonance imaging (7 T fMRI), a well validated cognitive task, and brain network analyses to investigate the functional networks underlying cognitive reasoning in individuals with corpus callosum dysgenesis (CCD), an anatomical abnormality that affects the corpus callosum. Participants with CCD were asked to solve cognitive reasoning problems while their brain activity was measured using fMRI. The complexity of these problems was parametrically varied by changing the complexity of relations that needed to be established between shapes within each problem matrix. Behaviorally, participants showed a typical reduction in task performance as problem complexity increased. Task-evoked neural activity was observed in brain regions known to constitute two key cognitive control systems: the fronto-parietal and cingulo-opercular networks. Under low complexity demands, network topology and the patterns of local neural activity in the CCD group closely resembled those observed in neurotypical controls. By contrast, when asked to solve more complex problems, participants with CCD showed a reduction in neural activity and connectivity within the fronto-parietal network. These complexity-induced, as opposed to resting-state, differences in functional network activity help resolve the apparent paradox between preserved network architecture found at rest in CCD individuals, and the heterogeneous deficits they display in response to cognitive task demands [preprint: https://doi.org/10.1101/312629].

PMID: 30473430 [PubMed - as supplied by publisher]

Neuroimaging Applications in Tourette's Syndrome.

Tue, 11/27/2018 - 12:00
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Neuroimaging Applications in Tourette's Syndrome.

Int Rev Neurobiol. 2018;143:65-108

Authors: Martino D, Ganos C, Worbe Y

Abstract
Tics are neurodevelopmental hyperkinetic symptoms typically associated with unpleasant sensory experiences called premonitory urges. Tourette syndrome (TS) is the primary chronic tic disorder for which medical surveillance is most frequently required, and is associated with a complex phenotypical spectrum encompassing different types of abnormal behaviors. Animal models of tics support their link to phasic activity changes throughout the sensorimotor loop of the cortico-basal ganglia-thalamo-cortical network. Event-related functional magnetic resonance imaging (fMRI) studies on patients with TS showed that the supplementary motor area relays preparatory signals related to tics to the primary motor area and other cortical regions relevant to action monitoring, following which cortico-basal ganglia-thalamo-cortical activation leads to the manifestation of tics. Despite their methodological heterogeneity, structural MRI studies highlighted the existence of anatomical markers of distinct sub-phenotypes of the TS spectrum. Initial evidence suggests that combining MRI structural methods and functional intrinsic connectivity assessed during resting state could even discriminate between TS patients and control groups. MR-spectroscopy and positron emission tomography studies suggest that TS may be related to a complex interplay between different neurotransmitters (particularly dopamine, GABA and glutamate), but discrepancy across studies prevents firm conclusions. Recent volumetric, cortical thickness and fMRI studies results showed an association between premonitory urges and somatosensory and insular cortical regions, involved in the processing of interoceptive and enteroceptive stimuli and motor output modulation. Finally, both structural and functional MRI studies have provided important support to the subtyping of the TS spectrum with respect to behavioral co-morbidities, in line with a "dimensional approach" to the classification of neuropsychiatric disorders, which is based on the identification of neurocognitive endophenotypes and of their anatomical substrate.

PMID: 30473198 [PubMed - in process]

Spatial and Temporal Organization of the Individual Human Cerebellum.

Tue, 11/27/2018 - 12:00
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Spatial and Temporal Organization of the Individual Human Cerebellum.

Neuron. 2018 Nov 21;100(4):977-993.e7

Authors: Marek S, Siegel JS, Gordon EM, Raut RV, Gratton C, Newbold DJ, Ortega M, Laumann TO, Adeyemo B, Miller DB, Zheng A, Lopez KC, Berg JJ, Coalson RS, Nguyen AL, Dierker D, Van AN, Hoyt CR, McDermott KB, Norris SA, Shimony JS, Snyder AZ, Nelson SM, Barch DM, Schlaggar BL, Raichle ME, Petersen SE, Greene DJ, Dosenbach NUF

Abstract
The cerebellum contains the majority of neurons in the human brain and is unique for its uniform cytoarchitecture, absence of aerobic glycolysis, and role in adaptive plasticity. Despite anatomical and physiological differences between the cerebellum and cerebral cortex, group-average functional connectivity studies have identified networks related to specific functions in both structures. Recently, precision functional mapping of individuals revealed that functional networks in the cerebral cortex exhibit measurable individual specificity. Using the highly sampled Midnight Scan Club (MSC) dataset, we found the cerebellum contains reliable, individual-specific network organization that is significantly more variable than the cerebral cortex. The frontoparietal network, thought to support adaptive control, was the only network overrepresented in the cerebellum compared to the cerebral cortex (2.3-fold). Temporally, all cerebellar resting state signals lagged behind the cerebral cortex (125-380 ms), supporting the hypothesis that the cerebellum engages in a domain-general function in the adaptive control of all cortical processes.

PMID: 30473014 [PubMed - in process]

The instability of functional connectivity in patients with schizophrenia and their siblings: A dynamic connectivity study.

Tue, 11/27/2018 - 12:00
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The instability of functional connectivity in patients with schizophrenia and their siblings: A dynamic connectivity study.

Schizophr Res. 2018 05;195:183-189

Authors: Guo S, Zhao W, Tao H, Liu Z, Palaniyappan L

Abstract
BACKGROUND: The distributed connectivity among brain regions is in a constant state of flux, even when a subject is at rest. This instability (temporal variability), when optimal, may contribute to efficient cross-network communications. We investigate the role of this variability in the genetic diathesis and symptom expression of schizophrenia.
METHODS: Resting state functional MRI data acquired from 116 subjects (28 patients with schizophrenia, 28 siblings and 60 matched healthy controls). Using a sliding-window dynamic connectivity approach, we quantified the variability of whole-brain connectivity (dynamic functional connectivity or dFC) of each of the 90 brain regions obtained using a parcellation scheme that covered all contiguous brain regions of the cerebral cortex.
RESULTS: We noted a high degree of instability anchored on the precuneus in patients with schizophrenia compared to both healthy controls (t=3.60, p=0.0005) and unaffected siblings (t=3.61, p=0.001) indicating a role for dFC of precuneus in the clinical expression of schizophrenia. Compared to patients, siblings also showed an increase in medial orbitofrontal but reduced putaminal instability; these latter changes were not seen in patients when compared to controls, indicating a lack of specificity for diathesis or expression related effects.
CONCLUSIONS: Instability in the intrinsic connectivity of precuneus, a functional core hub with a major role in task-free self-processing, is likely to be a core substrate of the clinical expression of schizophrenia.

PMID: 29153446 [PubMed - indexed for MEDLINE]

Visual deprivation selectively reshapes the intrinsic functional architecture of the anterior insula subregions.

Tue, 11/27/2018 - 12:00
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Visual deprivation selectively reshapes the intrinsic functional architecture of the anterior insula subregions.

Sci Rep. 2017 03 30;7:45675

Authors: Liu L, Yuan C, Ding H, Xu Y, Long M, Li Y, Liu Y, Jiang T, Qin W, Shen W, Yu C

Abstract
The anterior insula (AI) is the core hub of salience network that serves to identify the most relevant stimuli among vast sensory inputs and forward them to higher cognitive regions to guide behaviour. As blind subjects were usually reported with changed perceptive abilities for salient non-visual stimuli, we hypothesized that the resting-state functional network of the AI is selectively reorganized after visual deprivation. The resting-state functional connectivity (FC) of the bilateral dorsal and ventral AI was calculated for twenty congenitally blind (CB), 27 early blind (EB), 44 late blind (LB) individuals and 50 sighted controls (SCs). The FCs of the dorsal AI were strengthened with the dorsal visual stream, while weakened with the ventral visual stream in the blind than the SCs; in contrast, the FCs of the ventral AI of the blind was strengthened with the ventral visual stream. Furthermore, these strengthened FCs of both the dorsal and ventral AI were partially negatively associated with the onset age of blindness. Our result indicates two parallel pathways that selectively transfer non-visual salient information between the deprived "visual" cortex and salience network in blind subjects.

PMID: 28358391 [PubMed - indexed for MEDLINE]

Resting state functional connectivity patterns associated with pharmacological treatment resistance in temporal lobe epilepsy.

Mon, 11/26/2018 - 11:20

Resting state functional connectivity patterns associated with pharmacological treatment resistance in temporal lobe epilepsy.

Epilepsy Res. 2018 Nov 17;149:37-43

Authors: Pressl C, Brandner P, Schaffelhofer S, Blackmon K, Dugan P, Holmes M, Thesen T, Kuzniecky R, Devinsky O, Freiwald WA

Abstract
There are no functional imaging based biomarkers for pharmacological treatment response in temporal lobe epilepsy (TLE). In this study, we investigated whether there is an association between resting state functional brain connectivity (RsFC) and seizure control in TLE. We screened a large database containing resting state functional magnetic resonance imaging (Rs-fMRI) data from 286 epilepsy patients. Patient medical records were screened for seizure characterization, EEG reports for lateralization and location of seizure foci to establish uniformity of seizure localization within patient groups. Rs-fMRI data from patients with well-controlled left TLE, patients with treatment-resistant left TLE, and healthy controls were analyzed. Healthy controls and cTLE showed similar functional connectivity patterns, whereas trTLE exhibited a significant bilateral decrease in thalamo-hippocampal functional connectivity. This work is the first to demonstrate differences in neural network connectivity between well-controlled and treatment-resistant TLE. These differences are spatially highly focused and suggest sites for the etiology and possibly treatment of TLE. Altered thalamo-hippocampal RsFC thus is a potential new biomarker for TLE treatment resistance.

PMID: 30472489 [PubMed - as supplied by publisher]

Age-related differences in default-mode network connectivity in response to intermittent theta-burst stimulation and its relationships with maintained cognition and brain integrity in healthy aging.

Mon, 11/26/2018 - 11:20

Age-related differences in default-mode network connectivity in response to intermittent theta-burst stimulation and its relationships with maintained cognition and brain integrity in healthy aging.

Neuroimage. 2018 Nov 22;:

Authors: Abellaneda-Pérez K, Vaqué-Alcázar L, Vidal-Piñeiro D, Jannati A, Solana E, Bargalló N, Santarnecchi E, Pascual-Leone A, Bartrés-Faz D

Abstract
The default-mode network (DMN) is affected by advancing age, where particularly long-range connectivity has been consistently reported to be reduced as compared to young individuals. We examined whether there were any differences in the effects of intermittent theta-burst stimulation (iTBS) in DMN connectivity between younger and older adults, its associations with cognition and brain integrity, as well as with long-term cognitive status. Twenty-four younger and 27 cognitively normal older adults were randomly assigned to receive real or sham iTBS over the left inferior parietal lobule between two resting-state functional magnetic resonance imaging (rs-fMRI) acquisitions. Three years later, those older adults who had received real iTBS underwent a cognitive follow-up assessment. Among the younger adults, functional connectivity increased following iTBS in distal DMN areas from the stimulation site. In contrast, older adults exhibited increases in connectivity following iTBS in proximal DMN regions. Moreover, older adults with functional responses to iTBS resembling those of the younger participants exhibited greater brain integrity and higher cognitive performance at baseline and at the 3-year follow-up, along with less cognitive decline. Finally, we observed that 'young-like' functional responses to iTBS were also related to the educational background attained amongst older adults. The present study reveals that functional responses of the DMN to iTBS are modulated by age. Furthermore, combining iTBS and rs-fMRI in older adults may allow characterizing distinctive cognitive profiles in aging and its progression, probably reflecting network plasticity systems that may entail a neurobiological substrate of cognitive reserve.

PMID: 30472372 [PubMed - as supplied by publisher]

Interactions between gut permeability and brain structure and function in health and irritable bowel syndrome.

Mon, 11/26/2018 - 11:20

Interactions between gut permeability and brain structure and function in health and irritable bowel syndrome.

Neuroimage Clin. 2018 Nov 17;:

Authors: Witt ST, Bednarska O, Keita ÅV, Icenhour A, Jones MP, Elsenbruch S, Söderholm JD, Engström M, Mayer EA, Walter S

Abstract
Changes in brain-gut interactions have been implicated in the pathophysiology of chronic visceral pain in irritable bowel syndrome (IBS). Different mechanisms of sensitization of visceral afferent pathways may contribute to the chronic visceral pain reports and associated brain changes that characterize IBS. They include increased gut permeability and gut associated immune system activation, and an imbalance in descending pain inhibitory and facilitatory mechanisms. In order to study the involvement of these mechanisms, correlations between gut epithelial permeability and live bacterial passage, and structural and functional brain connectivity were measured in women with moderate-to-severe IBS and healthy women. The relationships between gut permeability and functional and anatomical connectivity were significantly altered in IBS compared with the healthy women. IBS participants with lower epithelial permeability reported increased IBS symptoms, which was associated with increased functional and structural connectivity in endogenous pain facilitation regions. The findings suggest that relationships between gut permeability and the brain are significantly altered in IBS and suggest the existence of IBS subtypes based on these interactions.

PMID: 30472166 [PubMed - as supplied by publisher]

Prism adaptation changes resting-state functional connectivity in the dorsal stream of visual attention networks in healthy adults: A fMRI study.

Mon, 11/26/2018 - 11:20

Prism adaptation changes resting-state functional connectivity in the dorsal stream of visual attention networks in healthy adults: A fMRI study.

Cortex. 2018 Oct 31;:

Authors: Tsujimoto K, Mizuno K, Nishida D, Tahara M, Yamada E, Shindo S, Kasuga S, Liu M

Abstract
Unilateral spatial neglect (USN) can be defined as a failure to orient to contra-lesional stimuli in the absence of either sensory or motor defects. Although the behavioral and clinical effects of prism adaptation (PA) are widely accepted, its underlying mechanisms are still controversial. However, recent neuroimaging and neurophysiological studies support the idea that PA affects the visual attention and sensorimotor networks including in the parietal cortex and cerebellum. We investigate the effect of PA on functional connectivity (FC) in attention and sensorimotor networks, evaluating changes of resting-state FC before and after PA in healthy individuals using functional magnetic resonance imaging (fMRI). MR sessions were conducted before PA, after PA (Post1), and 1 h after PA (Post2). The FC between the right frontal eye (FEF) field and the right intraparietal sulcus was significantly decreased at Post1 and that between the right FEF and the right anterior cingulate cortex was significantly increased after PA and recovered within 1 h. This is the first study to demonstrate transient changes of resting-state FC in the right dorsal attention network (DAN) by PA in healthy adults using fMRI. These results will contribute to the elucidation of the underling mechanism of PA therapy and to devising new therapies for USN and/or other higher cortical dysfunctions.

PMID: 30471844 [PubMed - as supplied by publisher]

Advances and challenges in neuroimaging studies on the effects of serotonergic hallucinogens: Contributions of the resting brain.

Mon, 11/26/2018 - 11:20

Advances and challenges in neuroimaging studies on the effects of serotonergic hallucinogens: Contributions of the resting brain.

Prog Brain Res. 2018;242:159-177

Authors: Müller F, Liechti ME, Lang UE, Borgwardt S

Abstract
The effects of hallucinogenic drugs on the human brain have been studied since the earliest days of neuroimaging in the 1990s. However, approaches are often hard to compare and results are heterogeneous. In this chapter, we summarize studies investigating the effects of hallucinogens on the resting brain, with a special emphasis on replicability and limitations. In previous studies, similarities were observed between psilocybin, LSD, and ayahuasca, with respect to decreases in cerebral blood flow and increases in global functional connectivity in the precuneus and thalamus. Additionally, LSD consistently decreased functional connectivity within distinct resting state networks. Little convergence was observed for connectivity between networks and for blood flow in other brain regions. Although these studies are limited by small sample sizes and might be biased by unspecific drug effects on physiological parameters and the vascular system, current results indicate that neuroimaging could be a useful tool to elucidate the neuronal correlates of hallucinogenic effects.

PMID: 30471679 [PubMed - in process]

Amyloid beta-positive subjects exhibit longitudinal network-specific reductions in spontaneous brain activity.

Sun, 11/25/2018 - 16:20
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Amyloid beta-positive subjects exhibit longitudinal network-specific reductions in spontaneous brain activity.

Neurobiol Aging. 2018 Oct 11;74:191-201

Authors: Avants BB, Hutchison RM, Mikulskis A, Salinas-Valenzuela C, Hargreaves R, Beaver J, Chiao P, Alzheimer's Disease Neuroimaging Initiative

Abstract
Amyloid beta (Aβ) deposition and cognitive decline are key features of Alzheimer's disease. The relationship between Aβ status and changes in neuronal function over time, however, remains unclear. We evaluated the effect of baseline Aβ status on reference region spontaneous brain activity (SBA-rr) using resting-state functional magnetic resonance imaging and fluorodeoxyglucose positron emission tomography in patients with mild cognitive impairment. Patients (N = 62, [43 Aβ-positive]) from the Alzheimer's Disease Neuroimaging Initiative were divided into Aβ-positive and Aβ-negative groups via prespecified cerebrospinal fluid Aβ42 or 18F-florbetapir positron emission tomography standardized uptake value ratio cutoffs measured at baseline. We analyzed interaction of biomarker-confirmed Aβ status with SBA-rr change over a 2-year period using mixed-effects modeling. SBA-rr differences between Aβ-positive and Aβ-negative subjects increased significantly over time within subsystems of the default and visual networks. Changes exhibit an interaction with memory performance over time but were independent of glucose metabolism. Results reinforce the value of resting-state functional magnetic resonance imaging in evaluating Alzheimer''s disease progression and suggest spontaneous neuronal activity changes are concomitant with cognitive decline.

PMID: 30471630 [PubMed - as supplied by publisher]

Amplitude of Low Frequency Fluctuation (ALFF) study of the spontaneous brain activities of patients with phantom limb pain.

Sat, 11/24/2018 - 15:00
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Amplitude of Low Frequency Fluctuation (ALFF) study of the spontaneous brain activities of patients with phantom limb pain.

Eur Rev Med Pharmacol Sci. 2018 Nov;22(21):7164-7171

Authors: Du JG, Xiao H, Zuo YX

Abstract
OBJECTIVE: Our objective was to use Amplitude of Low-Frequency Fluctuation (ALFF) method to investigate the changes in spontaneous brain activity in HM patients and their relationships with clinical features.
PATIENTS AND METHODS: This study was set out to observe, using Functional magnetic resonance imaging (fMRI), the changes in spontaneous brain activity in patients with phantom limb pain (PLP). Eleven amputees with PLP closely matched in age, sex, and education in a right side lower limb were scanned using fMRI to measure the amplitude of low-frequency fluctuation (ALFF) and functional connectivity (FC) in the resting state of the brain (GPLP) before use of prosthetic. They were then scanned again after recovering from PLP (GPLPr) after use of artificial limbs. Eleven healthy volunteers (GC) were also scanned.
RESULTS: When compared to GC, GPLP exhibited decreased ALFF in the left inferior parietal lobule, and GPLPr exhibited decreased ALFF in the left precuneus. When compared to GPLP, GC showed positive FC in the part regions of the limbic system structure. When compared to GC, the positive FC in GPLPr was significantly decreased in the midbrain. Finally, when compared to GPLPr, GPLP showed significantly decreased positive FC in the right precuneus and inferior parietal lobe. The central nervous system shows functional changes in the resting state of the brain in patients with PLP, which may indicate the presence of neurobiological changes. The recovery time of the changes may be longer than the pain symptoms of patients.
CONCLUSIONS: The technique of fMRI of the resting network of the brain in patients with PLP may be able to be used to monitor clinical therapeutic effects.

PMID: 30468457 [PubMed - in process]

Shifts in the functional topography of frontal cortex-striatum connectivity in alcohol use disorder.

Sat, 11/24/2018 - 15:00
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Shifts in the functional topography of frontal cortex-striatum connectivity in alcohol use disorder.

Addict Biol. 2018 Nov 23;:

Authors: Gerchen MF, Rentsch A, Kirsch M, Kiefer F, Kirsch P

Abstract
Frontostriatal circuits are centrally involved in the selection of behavioral programs and play a prominent role in alcohol use disorder (AUD) as well as other mental disorders. However, how frontal regions change their striatal connectivity to implement adaptive cognitive control is still not fully understood. Here, we developed an approach for functional magnetic resonance imaging (fMRI) connectivity analysis in which we change the focus from connectivity to individual voxels towards spatial information about the location of strongest functional connectivity. In resting state data of n = 66 participants with AUD and n = 40 healthy controls (HC) we used the approach to estimate frontostriatal connectivity gradients consistent with nonhuman primate tract-tracing studies, characterized for each frontal voxel the striatal peak connectivity location on this gradient (PeaCoG), and tested for group differences and associations with clinical variables. We identified a cluster in the right orbitofrontal cortex (rOFC) with a peak connectivity shift towards ventral striatal regions in AUD. Reduced variability of rOFC striatal peak connectivity in the AUD group suggests a "clamping" to the ventral striatum as the underlying effect. Within the AUD group striatal peak connectivity in the superior frontal gyrus was associated with self-efficacy to abstain from alcohol, in the medial frontal and dorsolateral prefrontal cortex with alcohol dependency, and in the right inferior frontal gyrus with the urge to consume alcohol. Our results demonstrate that the functional topography of frontostriatal circuits exhibits interindividual variability, which provides insight into frontostriatal network adaptations in AUD and potentially other mental disorders.

PMID: 30468293 [PubMed - as supplied by publisher]

fMRI data processing in MRTOOL: to what extent does anatomical registration affect the reliability of functional results?

Sat, 11/24/2018 - 15:00
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fMRI data processing in MRTOOL: to what extent does anatomical registration affect the reliability of functional results?

Brain Imaging Behav. 2018 Nov 22;:

Authors: Ganzetti M, Taberna GA, Mantini D

Abstract
Spatial registration is an essential step in the analysis of fMRI data because it enables between-subject analyses of brain activity, measured either during task performance or in the resting state. In this study, we investigated how anatomical registration with MRTOOL affects the reliability of task-related fMRI activity. We used as a benchmark the results from two other spatial registration methods implemented in SPM12: the Unified Segmentation algorithm and the DARTEL toolbox. Structural alignment accuracy and the impact on functional activation maps were assessed with high-resolution T1-weighted images and a set of task-related functional volumes acquired in 10 healthy volunteers. Our findings confirmed that anatomical registration is a crucial step in fMRI data processing, contributing significantly to the total inter-subject variance of the activation maps. MRTOOL and DARTEL provided greater registration accuracy than Unified Segmentation. Although DARTEL had superior gray matter and white matter tissue alignment than MRTOOL, there were no significant differences between DARTEL and MRTOOL in test-retest reliability. Likewise, we found only limited differences in BOLD activation morphology between MRTOOL and DARTEL. The test-retest reliability of task-related responses was comparable between MRTOOL and DARTEL, and both proved superior to Unified Segmentation. We conclude that MRTOOL, which is suitable for single-subject processing of structural and functional MR images, is a valid alternative to other SPM12-based approaches that are intended for group analysis. MRTOOL now includes a normalization module for fMRI data and is freely available to the scientific community.

PMID: 30467743 [PubMed - as supplied by publisher]

Correspondence Between Resting-State and Episodic Memory-Task Related Networks in Elderly Subjects.

Sat, 11/24/2018 - 15:00
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Correspondence Between Resting-State and Episodic Memory-Task Related Networks in Elderly Subjects.

Front Aging Neurosci. 2018;10:362

Authors: Simon-Vermot L, Taylor ANW, Araque Caballero MÀ, Franzmeier N, Buerger K, Catak C, Janowitz D, Kambeitz-Ilankovic LM, Ertl-Wagner B, Duering M, Ewers M

Abstract
Resting-state fMRI studies demonstrated temporally synchronous fluctuations in brain activity among ensembles of brain regions, suggesting the existence of intrinsic functional networks. A spatial match between some of the resting-state networks and regional brain activation during cognitive tasks has been noted, suggesting that resting-state networks support particular cognitive abilities. However, the spatial match and predictive value of any resting-state network and regional brain activation during episodic memory is only poorly understood. In order to address this research gap, we obtained fMRI acquired both during rest and a face-name association task in 38 healthy elderly subjects. In separate independent component analyses, networks of correlated brain activity during rest or the episodic memory task were identified. For the independent components identified for task-based fMRI, the design matrix of successful encoding or retrieval trials was regressed against the time course of each of the component to identify significantly activated networks. Spatial regression was used to assess the match of resting-state networks against those related to successful memory encoding or retrieval. We found that resting-state networks covering the medial temporal, middle temporal, and frontal areas showed increased activity during successful encoding. Resting-state networks located within posterior brain regions showed increased activity during successful recognition. However, the level of resting-state network connectivity was not predictive of the task-related activity in these networks. These results suggest that a circumscribed number of functional networks detectable during rest become engaged during successful episodic memory. However, higher intrinsic connectivity at rest may not translate into higher network expression during episodic memory.

PMID: 30467476 [PubMed]

Comparison of Resting-State Brain Activation Detected by BOLD, Blood Volume and Blood Flow.

Sat, 11/24/2018 - 15:00
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Comparison of Resting-State Brain Activation Detected by BOLD, Blood Volume and Blood Flow.

Front Hum Neurosci. 2018;12:443

Authors: Zhang K, Huang D, Shah NJ

Abstract
Resting-state brain activity has been widely investigated using blood oxygenation level dependent (BOLD) contrast techniques. However, BOLD signal changes reflect a combination of the effects of cerebral blood flow (CBF), cerebral blood volume (CBV), as well as the cerebral metabolic rate of oxygen (CMRO2). In this study, resting-state brain activation was detected and compared using the following techniques: (a) BOLD, using a gradient-echo echo planar imaging (GE-EPI) sequence; (b) CBV-weighted signal, acquired using gradient and spin echo (GRASE) based vascular space occupancy (VASO); and (c) CBF, using pseudo-continuous arterial spin labeling (pCASL). Reliable brain networks were detected using VASO and ASL, including sensorimotor, auditory, primary visual, higher visual, default mode, salience and left/right executive control networks. Differences between the resting-state activation detected with ASL, VASO and BOLD could potentially be due to the different temporal signal-to-noise ratio (tSNR) and the short post-labeling delay (PLD) in ASL, along with differences in the spin-echo readout of VASO. It is also possible that the dynamics of spontaneous fluctuations in BOLD, CBV and CBF could differ due to biological reasons, according to their location within the brain.

PMID: 30467468 [PubMed]

Cesarean Delivery Impacts Infant Brain Development.

Sat, 11/24/2018 - 15:00
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Cesarean Delivery Impacts Infant Brain Development.

AJNR Am J Neuroradiol. 2018 Nov 22;:

Authors: Deoni SC, Adams SH, Li X, Badger TM, Pivik RT, Glasier CM, Ramakrishnaiah RH, Rowell AC, Ou X

Abstract
BACKGROUND AND PURPOSE: The cesarean delivery rate has increased globally in the past few decades. Neurodevelopmental outcomes associated with cesarean delivery are still unclear. This study investigated whether cesarean delivery has any effect on the brain development of offspring.
MATERIALS AND METHODS: A total of 306 healthy children were studied retrospectively. We included 3 cohorts: 2-week-old neonates (cohort 1, n = 32/11 for vaginal delivery/cesarean delivery) and 8-year-old children (cohort 2, n = 37/23 for vaginal delivery/cesarean delivery) studied at Arkansas Children's Hospital, and a longitudinal cohort of 3-month to 5-year-old children (cohort 3, n = 164/39 for vaginal delivery/cesarean delivery) studied independently at Brown University. Diffusion tensor imaging, myelin water fraction imaging, voxel-based morphometry, and/or resting-state fMRI data were analyzed to evaluate white matter integrity, myelination, gray matter volume, and/or functional connectivity, respectively.
RESULTS: While not all MR imaging techniques were shared across the institutions/cohorts, post hoc analyses showed similar results of potential effects of cesarean delivery. The cesarean delivery group in cohort 1 showed significantly lower white matter development in widespread brain regions and significantly lower functional connectivity in the brain default mode network, controlled for a number of potential confounders. No group differences were found in cohort 2 in white matter integrity or gray matter volume. Cohort 3 had significantly different trajectories of white matter myelination between groups, with those born by cesarean delivery having reduced myelin in infancy but normalizing with age.
CONCLUSIONS: Cesarean delivery may influence infant brain development. The impact may be transient because similar effects were not observed in older children. Further prospective and longitudinal studies may be needed to confirm these novel findings.

PMID: 30467219 [PubMed - as supplied by publisher]

Spontaneous cognitive processes and the behavioral validation of time-varying brain connectivity.

Fri, 11/23/2018 - 14:00
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Spontaneous cognitive processes and the behavioral validation of time-varying brain connectivity.

Netw Neurosci. 2018;2(4):397-417

Authors: Kucyi A, Tambini A, Sadaghiani S, Keilholz S, Cohen JR

Abstract
In cognitive neuroscience, focus is commonly placed on associating brain function with changes in objectively measured external stimuli or with actively generated cognitive processes. In everyday life, however, many forms of cognitive processes are initiated spontaneously, without an individual's active effort and without explicit manipulation of behavioral state. Recently, there has been increased emphasis, especially in functional neuroimaging research, on spontaneous correlated activity among spatially segregated brain regions (intrinsic functional connectivity) and, more specifically, on intraindividual fluctuations of such correlated activity on various time scales (time-varying functional connectivity). In this Perspective, we propose that certain subtypes of spontaneous cognitive processes are detectable in time-varying functional connectivity measurements. We define these subtypes of spontaneous cognitive processes and review evidence of their representations in time-varying functional connectivity from studies of attentional fluctuations, memory reactivation, and effects of baseline states on subsequent perception. Moreover, we describe how these studies are critical to validating the use of neuroimaging tools (e.g., fMRI) for assessing ongoing brain network dynamics. We conclude that continued investigation of the behavioral relevance of time-varying functional connectivity will be beneficial both in the development of comprehensive neural models of cognition, and in informing on best practices for studying brain network dynamics.

PMID: 30465033 [PubMed]

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