New resting-state fMRI related studies at PubMed

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Collective sparse symmetric non-negative matrix factorization for identifying overlapping communities in resting-state brain functional networks.

Thu, 11/09/2017 - 14:20
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Collective sparse symmetric non-negative matrix factorization for identifying overlapping communities in resting-state brain functional networks.

Neuroimage. 2017 Nov 05;:

Authors: Li X, Gan JQ, Wang H

Abstract
Resting-state functional magnetic resonance imaging (rs-fMRI) provides a valuable tool to study spontaneous brain activity. Using rs-fMRI, researchers have extensively studied the organization of the brain functional network and found several consistent communities consisting of functionally connected but spatially separated brain regions across subjects. However, increasing evidence in many disciplines has shown that most realistic complex networks have overlapping community structure. Only recently has the overlapping community structure drawn increasing interest in the domain of brain network studies. Another issue is that the inter-subject variability is often not directly reflected in the process of community detection at the group level. In this paper, we propose a novel method called collective sparse symmetric non-negative matrix factorization (cssNMF) to address these issues. The cssNMF approach identifies the group-level overlapping communities across subjects and in the meantime preserves the information of individual variation in brain functional network organization. To comprehensively validate cssNMF, a simulated fMRI dataset with ground-truth, a real rs-fMRI dataset with two repeated sessions and another different real rs-fMRI dataset have been used for performance comparison in the experiment. Experimental results show that the proposed cssNMF method accurately and stably identifies group-level overlapping communities across subjects as well as individual differences in network organization with neurophysiologically meaningful interpretations. This research extends our understanding of the common underlying community structures and individual differences in community strengths in brain functional network organization.

PMID: 29117581 [PubMed - as supplied by publisher]

Dynamic Network Communication in the Human Functional Connectome Predicts Perceptual Variability in Visual Illusion.

Thu, 11/09/2017 - 14:20
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Dynamic Network Communication in the Human Functional Connectome Predicts Perceptual Variability in Visual Illusion.

Cereb Cortex. 2016 Nov 22;:1-15

Authors: Wang Z, Zeljic K, Jiang Q, Gu Y, Wang W, Wang Z

Abstract
Ubiquitous variability between individuals in visual perception is difficult to standardize and has thus essentially been ignored. Here we construct a quantitative psychophysical measure of illusory rotary motion based on the Pinna-Brelstaff figure (PBF) in 73 healthy volunteers and investigate the neural circuit mechanisms underlying perceptual variation using functional magnetic resonance imaging (fMRI). We acquired fMRI data from a subset of 42 subjects during spontaneous and 3 stimulus conditions: expanding PBF, expanding modified-PBF (illusion-free) and expanding modified-PBF with physical rotation. Brain-wide graph analysis of stimulus-evoked functional connectivity patterns yielded a functionally segregated architecture containing 3 discrete hierarchical networks, commonly shared between rest and stimulation conditions. Strikingly, communication efficiency and strength between 2 networks predominantly located in visual areas robustly predicted individual perceptual differences solely in the illusory stimulus condition. These unprecedented findings demonstrate that stimulus-dependent, not spontaneous, dynamic functional integration between distributed brain networks contributes to perceptual variability in humans.

PMID: 29117288 [PubMed - as supplied by publisher]

Altered DMN functional connectivity and regional homogeneity in partial epilepsy patients: a seventy cases study.

Thu, 11/09/2017 - 14:20
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Altered DMN functional connectivity and regional homogeneity in partial epilepsy patients: a seventy cases study.

Oncotarget. 2017 Oct 06;8(46):81475-81484

Authors: Hu CY, Gao X, Long L, Long X, Liu C, Chen Y, Xie Y, Liu C, Xiao B, Hu ZY

Abstract
Purpose: Clinically diagnosed partial epilepsy is hard to be functionally diagnosed by regular electroencephalograph (EEG) and conventional magnetic resonance imaging (MRI). By collecting transient brain regional signals, blood oxygenation level-dependent (BOLD) function MRI (BOLD-fMRI) can provide brain function change information with high accuracy. By using resting state BOLD-fMRI technique, we aim to investigate the changes of brain function in partial epilepsy patients.
Methods: BOLD-fMRI scanning was performed in 70 partial epilepsy and 70 healthy people. BOLD-fMRI data was analyzed by using the Regional Homogeneity (ReHo) method and functional connectivity of Default Mode Network (DMN) methods. The abnormal brain functional connectivity in partial epilepsy patients was detected by Statistical Parametric Mapping 8 (SPM8) analysis.
Results: Compared to healthy group, epilepsy patients showed significant decreased ReHo in left inferior parietal lobule/pre- and post-central gyrus, right thalamus/paracentral lobule/Cerebellum anterior and posterior Lobe, bilateral insula. The DMN functional connectivity regions decreased significantly in right uncus, left Inferior parietal lobule, left supramarginal gyrus, left uncus, left parahippocampa gyrus, and left superior temporal gyrus, in epilepsy patients, compared to healthy controls.
Significance: This study clarified that both ReHo and functional connectivity of DMN decreased in partial epilepsy patients compared to healthy controls. While left inferior parietal lobule was detected in both ReHo and DMN, many other identified regions were different by using these two BOLD-fMRI techniques. We propose that both ReHo and DMN patterns in BOLD-fMRI may suggest networks responsible for partial epilepsy genesis or progression.

PMID: 29113406 [PubMed]

Altered putamen functional connectivity is associated with anxiety disorder in Parkinson's disease.

Thu, 11/09/2017 - 14:20
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Altered putamen functional connectivity is associated with anxiety disorder in Parkinson's disease.

Oncotarget. 2017 Oct 06;8(46):81377-81386

Authors: Wang X, Li J, Yuan Y, Wang M, Ding J, Zhang J, Zhu L, Shen Y, Zhang H, Zhang K

Abstract
In this study, we used resting state-functional magnetic resonance imaging (rs-fMRI) to explore altered putamen functional connectivity (FC) in Parkinson's disease patients with anxiety disorder. We divided 65 Parkinson's disease patients into anxiety (PD-A; n=18) and non-anxiety (PD-NA; n=45) groups based on a Hamilton Anxiety Rating Scale cutoff score of 12. The PD-A patients exhibited altered putamen FC with cortical and subcortical regions. The PD-A patients showed enhanced putamen FC with the caudatum, which correlated with increased emotional processing during anxiety. Decreased putamen FC with the orbitofrontal gyrus and cerebellum also correlated with increased anxiety in Parkinson's disease. Our findings demonstrate that anxiety disorder in Parkinson's disease is associated with abnormal putamen FC networks, especially with caudatum, orbitofrontal gyrus and cerebellum.

PMID: 29113397 [PubMed]

Chemotherapy-induced changes of cerebral activity in resting-state functional magnetic resonance imaging and cerebral white matter in diffusion tensor imaging.

Thu, 11/09/2017 - 14:20
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Chemotherapy-induced changes of cerebral activity in resting-state functional magnetic resonance imaging and cerebral white matter in diffusion tensor imaging.

Oncotarget. 2017 Oct 06;8(46):81273-81284

Authors: Mo C, Lin H, Fu F, Lin L, Zhang J, Huang M, Wang C, Xue Y, Duan Q, Lin W, Chen X

Abstract
While chemotherapy related cognitive disorder has been described in many studies, but we still lack relatively reliable and objective diagnostic tools, and there are few similar studies in Asian patients. We recruited Asian breast cancer patients to perform a cohort study to uncover chemotherapy related cognitive disorder by using resting-state functioning magnetic resonance imaging (RS-fMRI) and magnetic resonance diffusion tensor imaging (DTI) combined with neuropsychologic assessments. This is the first prospective study which combines RS-fMRI and DTI to detect chemotherapy related cognitive disorder. The neuropsychologic tests and MRI were performed before and after the chemotherapy. The healthy controls were tested at matched times. The chemotherapy-treated group performed worse on memory and we found significant changes in the cerebellum, right orbitofrontal area, right middle and superior temporal gyrus, right subcentral area, left dorsolateral prefrontal cortex, and precentral gyrus in RS-fMRI after chemotherapy. We found changes in the fornix and superior fronto-occipital fasciculus with DTI. There was a correlation between some cognitive function and MRI measurements in the correlation analysis, but it was not significant after false discovery rate (FDR) multiple testing corrections. The results indicate that RS-fMRI and DTI may be a prospective application for assessing chemotherapy related cognitive disorder.

PMID: 29113386 [PubMed]

Differential association of default mode network connectivity and rumination in healthy individuals and remitted MDD patients.

Thu, 11/09/2017 - 14:20
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Differential association of default mode network connectivity and rumination in healthy individuals and remitted MDD patients.

Soc Cogn Affect Neurosci. 2016 Nov;11(11):1792-1801

Authors: Lois G, Wessa M

Abstract
Rumination is associated with increased default-mode network (DMN) activity and functional connectivity (FC) in depressed and healthy individuals. In this study, we sought to examine the relationship between self-reported rumination and resting-state FC in the DMN and cognitive control networks in 25 remitted depressed patients and 25 matched healthy controls using independent component and seed-based analyses. We also explored potential group differences in the global pattern of resting-state FC. Healthy subjects with increased levels of rumination exhibited increased anterior DMN connectivity with the posterior DMN and the dorsal attention network and low connectivity within the anterior DMN. On the other hand, remitted depressed ruminators patients were associated with the opposite FC pattern in these regions. Based on global FC patterns, a support vector machine algorithm correctly classified 92% of the subjects into their respective group by a leave-one-out cross-validation. Whole-brain FC analysis also revealed a group by rumination interaction effect within the DMN. The present findings highlight the different functional roles of the anterior and the posterior DMN, and provide novel insights into the underlying neural mechanisms leading to depression relapse.

PMID: 27405616 [PubMed - indexed for MEDLINE]

Role of spontaneous brain activity in explicit and implicit aspects of cognitive flexibility under socially conflicting situations: a resting-state fMRI study using fractional amplitude of low-frequency fluctuations.

Wed, 11/08/2017 - 13:00
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Role of spontaneous brain activity in explicit and implicit aspects of cognitive flexibility under socially conflicting situations: a resting-state fMRI study using fractional amplitude of low-frequency fluctuations.

Neuroscience. 2017 Oct 27;:

Authors: Fujino J, Tei S, Jankowski KF, Kawada R, Murai T, Takahashi H

Abstract
We are constantly exposed to socially conflicting situations in everyday life, and cognitive flexibility is essential for adaptively coping with such difficulties. Flexible goal choice and pursuit are not exclusively conscious, and therefore cognitive flexibility involves both explicit and implicit forms of processing. However, it is unclear how individual differences in explicit and implicit aspects of flexibility are associated with neural activity in a resting state. Here, we measured intrinsic fractional amplitude of low-frequency fluctuations (fALFF) by resting-state functional magnetic imaging (RS-fMRI) as an indicator of regional brain spontaneous activity, together with explicit and implicit aspects of cognitive flexibility using the Cognitive Flexibility Scale (CFS) and Implicit Association Test (IAT). Consistent with the dual processing theory, there was a strong association between explicit aspects of flexibility (CFS score) and "rationalism" thinking style and between implicit aspects (IAT effect) and "experientialism." The level of explicit flexibility was also correlated with fALFF values in the left lateral prefrontal cortex, whereas the level of implicit flexibility was correlated with fALFF values in the right cerebellum. Furthermore, the fALFF values in both regions predicted individual preference for flexible decision-making strategy in a vignettes simulation task. These results add to our understanding of the neural mechanisms underlying flexible decision-making for solving social conflicts. More generally, our findings highlight the utility of RS-fMRI combined with both explicit and implicit psychometric measures for better understanding individual differences in social cognition.

PMID: 29111359 [PubMed - as supplied by publisher]

Integrated cross-network connectivity of amygdala, insula, and subgenual cingulate associated with facial emotion perception in healthy controls and remitted major depressive disorder.

Wed, 11/08/2017 - 13:00
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Integrated cross-network connectivity of amygdala, insula, and subgenual cingulate associated with facial emotion perception in healthy controls and remitted major depressive disorder.

Cogn Affect Behav Neurosci. 2017 Nov 06;:

Authors: Jenkins LM, Stange JP, Barba A, DelDonno SR, Kling LR, Briceño EM, Weisenbach SL, Phan KL, Shankman SA, Welsh RC, Langenecker SA

Abstract
Emotion perception deficits could be due to disrupted connectivity of key nodes in the salience and emotion network (SEN), including the amygdala, subgenual anterior cingulate cortex (sgACC), and insula. We examined SEN resting-state (rs-)fMRI connectivity in rMDD in relation to Facial Emotion Perception Test (FEPT) performance. Fifty-two medication-free people ages 18 to 23 years participated. Twenty-seven had major depressive disorder (MDD) in remission (rMDD, 10 males), as MDD is associated with emotion perception deficits and alterations in rsfMRI. Twenty-five healthy controls (10 males) also participated. Participants completed the FEPT during fMRI, in addition to an 8-minute eyes-open resting-state scan. Seed regions of interest were defined in the amygdala, anterior insula and sgACC. Multiple regression analyses co-varied diagnostic group, sex and movement parameters. Emotion perception accuracy was positively associated with connectivity between amygdala seeds and regions primarily in the SEN and cognitive control network (CCN), and also the default mode network (DMN). Accuracy was also positively associated with connectivity between the sgACC seeds and other SEN regions, and the DMN, particularly for the right sgACC. Connectivity negatively associated with emotion perception was mostly with regions outside of these three networks, other than the left insula and part of the DMN. This study is the first to our knowledge to demonstrate relationships between facial emotion processing and resting-state connectivity with SEN nodes and between SEN nodes and regions located within other neural networks.

PMID: 29110183 [PubMed - as supplied by publisher]

Cognitive behavioral therapy increases amygdala connectivity with the cognitive control network in both MDD and PTSD.

Wed, 11/08/2017 - 13:00
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Cognitive behavioral therapy increases amygdala connectivity with the cognitive control network in both MDD and PTSD.

Neuroimage Clin. 2017;14:464-470

Authors: Shou H, Yang Z, Satterthwaite TD, Cook PA, Bruce SE, Shinohara RT, Rosenberg B, Sheline YI

Abstract
BACKGROUND: Both major depressive disorder (MDD) and post-traumatic stress disorder (PTSD) are characterized by alterations in intrinsic functional connectivity. Here we investigated changes in intrinsic functional connectivity across these disorders as a function of cognitive behavioral therapy (CBT), an effective treatment in both disorders.
METHODS: 53 unmedicated right-handed participants were included in a longitudinal study. Patients were diagnosed with PTSD (n = 18) and MDD (n = 17) with a structured diagnostic interview and treated with 12 sessions of manualized CBT over a 12-week period. Patients received an MRI scan (Siemens 3 T Trio) before and after treatment. Longitudinal functional principal components analysis (LFPCA) was performed on functional connectivity of the bilateral amygdala with the fronto-parietal network. A matched healthy control group (n = 18) was also scanned twice for comparison.
RESULTS: LFPCA identified four eigenimages or principal components (PCs) that contributed significantly to the longitudinal change in connectivity. The second PC differentiated CBT-treated patients from controls in having significantly increased connectivity of the amygdala with the fronto-parietal network following CBT.
LIMITATIONS: Analysis of CBT-induced amygdala connectivity changes was restricted to the a priori determined fronto-parietal network. Future studies are needed to determine the generalizability of these findings, given the small and predominantly female sample.
CONCLUSION: We found evidence for the hypothesis that CBT treatment is associated with changes in connectivity between the amygdala and the fronto-parietal network. CBT may work by strengthening connections between the amygdala and brain regions that are involved in cognitive control, potentially providing enhanced top-down control of affective processes that are dysregulated in both MDD and PTSD.

PMID: 28275546 [PubMed - indexed for MEDLINE]

Dynamic association between perfusion and white matter integrity across time since injury in Veterans with history of TBI.

Wed, 11/08/2017 - 13:00
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Dynamic association between perfusion and white matter integrity across time since injury in Veterans with history of TBI.

Neuroimage Clin. 2017;14:308-315

Authors: Clark AL, Bangen KJ, Sorg SF, Schiehser DM, Evangelista ND, McKenna B, Liu TT, Delano-Wood L

Abstract
OBJECTIVE: Cerebral blood flow (CBF) plays a critical role in the maintenance of neuronal integrity, and CBF alterations have been linked to deleterious white matter changes. Although both CBF and white matter microstructural alterations have been observed within the context of traumatic brain injury (TBI), the degree to which these pathological changes relate to one another and whether this association is altered by time since injury have not been examined. The current study therefore sought to clarify associations between resting CBF and white matter microstructure post-TBI.
METHODS: 37 veterans with history of mild or moderate TBI (mmTBI) underwent neuroimaging and completed health and psychiatric symptom questionnaires. Resting CBF was measured with multiphase pseudocontinuous arterial spin labeling (MPPCASL), and white matter microstructural integrity was measured with diffusion tensor imaging (DTI). The cingulate cortex and cingulum bundle were selected as a priori regions of interest for the ASL and DTI data, respectively, given the known vulnerability of these regions to TBI.
RESULTS: Regression analyses controlling for age, sex, and posttraumatic stress disorder (PTSD) symptoms revealed a significant time since injury × resting CBF interaction for the left cingulum (p < 0.005). Decreased CBF was significantly associated with reduced cingulum fractional anisotropy (FA) in the chronic phase; however, no such association was observed for participants with less remote TBI.
CONCLUSIONS: Our results showed that reduced CBF was associated with poorer white matter integrity in those who were further removed from their brain injury. Findings provide preliminary evidence of a possible dynamic association between CBF and white matter microstructure that warrants additional consideration within the context of the negative long-term clinical outcomes frequently observed in those with history of TBI. Additional cross-disciplinary studies integrating multiple imaging modalities (e.g., DTI, ASL) and refined neuropsychiatric assessment are needed to better understand the nature, temporal course, and dynamic association between brain changes and clinical outcomes post-injury.

PMID: 28210542 [PubMed - indexed for MEDLINE]

Methylphenidate alters brain connectivity after enhanced physical performance.

Tue, 11/07/2017 - 12:00

Methylphenidate alters brain connectivity after enhanced physical performance.

Brain Res. 2017 Oct 28;:

Authors: King M, Breda KV, Rauch LH, Brooks SJ, Stein DJ, Ipser J

Abstract
Muscle fatigue is a disturbed homeostatic state characterized by a temporary inability to maintain force output and has lasting effects on the brain in the period immediately after exercise, such as decreased interhemispheric functional connectivity (FC). Stimulants that increase dopamine and norepinephrine neurotransmission can enhance performance during muscle fatiguing exercise (i.e. are ergogenic). We recently demonstrated that methylphenidate (MPH) increased force output and increased FC between the insular (IC) and hand motor cortex during a fatiguing handgrip task. However, whether resting FC is altered in the recovery period after enhanced force is unknown. The objective of these follow-up analyses was to examine the effects of performing a fatiguing handgrip task with MPH on subsequent resting state FC. In a double-blind counter-balanced design, participants ingested placebo or MPH and in a magnetic resonance imaging scanner performed: a six-minute pre-task resting scan, a fatiguing handgrip task during scanning, and then a sixminute post-task resting scan. We investigated task-related force and resting state FC pre and post task between: (1) interhemispheric motor cortex (M1) FC and (2) the right IC and left hand motor area. We found reduced interhemispheric M1 FC post task and that this decrease was negatively associated with percent increase in mean trial force in MPH conditions. Further, MPH but not placebo increased right IC - left hand motor area FC post task. This study demonstrates that using MPH during a muscle fatiguing task has lasting effects on the brain that are markedly different from drug naïve conditions.

PMID: 29107662 [PubMed - as supplied by publisher]

Distance-dependent alterations in local functional connectivity in drug-naive major depressive disorder.

Tue, 11/07/2017 - 12:00

Distance-dependent alterations in local functional connectivity in drug-naive major depressive disorder.

Psychiatry Res. 2017 Oct 25;270:80-85

Authors: Zhu J, Lin X, Lin C, Zhuo C

Abstract
Previous studies using resting-state functional magnetic resonance imaging (fMRI) have found abnormal functional connectivity in patients with major depressive disorder (MDD). Yet, effect of distance thresholds on local functional connectivity changes in MDD is largely unknown. Here, we used resting-state fMRI data and functional connectivity strength (FCS) method to test local functional connectivity differences at different distance thresholds between 47 drug-naive patients with MDD and 47 healthy controls. For the distribution of functional brain hubs with high local FCS, the overall changing trend from distance thresholds of 10mm to 100mm was from lateral to medial. Compared to controls, MDD patients exhibited decreased local FCS independent of distance threshold in the sensorimotor system (postcentral gyrus, paracentral lobule, and supplementary motor area). MDD Patients exhibited increased local FCS in the inferior temporal gyrus at two lower distance thresholds (20mm and 30mm) and a higher distance threshold (100mm). In addition, MDD patients showed increased local FCS in the putamen at higher distance thresholds (80-100mm). These findings suggest that local functional connectivity abnormalities in MDD are dependent on distance thresholds and that future studies should take the distance thresholds into account when measuring local functional connectivity in MDD.

PMID: 29107212 [PubMed - as supplied by publisher]

Intrinsic Frequency Specific Brain Networks for Identification of MCI individuals using resting-state fMRI.

Tue, 11/07/2017 - 12:00

Intrinsic Frequency Specific Brain Networks for Identification of MCI individuals using resting-state fMRI.

Neurosci Lett. 2017 Oct 26;:

Authors: Qian L, Zheng L, Shang Y, Zhang Y, Zhang Y, Alzheimer’s disease Neuroimaging Initiative

Abstract
Numerous brain oscillations are well organized into several brain rhythms to support complex brain activities within distinct frequency bands. These rhythms temporally coexist in the same or different brain areas and may interact with each other with specific properties and physiological functions. However, the identification and evaluation of these various brain rhythms derived from BOLD-fMRI signals are obscure. To address this issue, we introduced a data-driven method named Complementary Ensemble Empirical Mode Decomposition (CEEMD) to automatically decompose the BOLD oscillations into several brain rhythms within distinct frequency bands. Thereafter, in order to evaluate the performance of CEEMD in the detection of subtle BOLD signals, a novel CEEMD-based high-dimensional pattern classification framework was proposed to accurately identify mild cognitive impairment individuals from the healthy controls. Our results showed CEEMD is a stable frequency decomposition method. Furthermore, CEEMD-based frequency specific topological profiles provided a classification accuracy of 93.33%, which was saliently higher than that of the conventional frequency separation based scheme. Importantly, our findings demonstrated that CEEMD could provide an effective means for brain oscillation separation, by which a more meaningful frequency bins could be used to detect the subtle changes embedded in the BOLD signals.

PMID: 29107088 [PubMed - as supplied by publisher]

Identifying Autism from Resting-State fMRI Using Long Short-Term Memory Networks.

Tue, 11/07/2017 - 12:00
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Identifying Autism from Resting-State fMRI Using Long Short-Term Memory Networks.

Mach Learn Med Imaging. 2017 Sep;10541:362-370

Authors: Dvornek NC, Ventola P, Pelphrey KA, Duncan JS

Abstract
Functional magnetic resonance imaging (fMRI) has helped characterize the pathophysiology of autism spectrum disorders (ASD) and carries promise for producing objective biomarkers for ASD. Recent work has focused on deriving ASD biomarkers from resting-state functional connectivity measures. However, current efforts that have identified ASD with high accuracy were limited to homogeneous, small datasets, while classification results for heterogeneous, multi-site data have shown much lower accuracy. In this paper, we propose the use of recurrent neural networks with long short-term memory (LSTMs) for classification of individuals with ASD and typical controls directly from the resting-state fMRI time-series. We used the entire large, multi-site Autism Brain Imaging Data Exchange (ABIDE) I dataset for training and testing the LSTM models. Under a cross-validation framework, we achieved classification accuracy of 68.5%, which is 9% higher than previously reported methods that used fMRI data from the whole ABIDE cohort. Finally, we presented interpretation of the trained LSTM weights, which highlight potential functional networks and regions that are known to be implicated in ASD.

PMID: 29104967 [PubMed]

Cerebellum and neurodegenerative diseases: Beyond conventional magnetic resonance imaging.

Tue, 11/07/2017 - 12:00
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Cerebellum and neurodegenerative diseases: Beyond conventional magnetic resonance imaging.

World J Radiol. 2017 Oct 28;9(10):371-388

Authors: Mormina E, Petracca M, Bommarito G, Piaggio N, Cocozza S, Inglese M

Abstract
The cerebellum plays a key role in movement control and in cognition and cerebellar involvement is described in several neurodegenerative diseases. While conventional magnetic resonance imaging (MRI) is widely used for brain and cerebellar morphologic evaluation, advanced MRI techniques allow the investigation of cerebellar microstructural and functional characteristics. Volumetry, voxel-based morphometry, diffusion MRI based fiber tractography, resting state and task related functional MRI, perfusion, and proton MR spectroscopy are among the most common techniques applied to the study of cerebellum. In the present review, after providing a brief description of each technique's advantages and limitations, we focus on their application to the study of cerebellar injury in major neurodegenerative diseases, such as multiple sclerosis, Parkinson's and Alzheimer's disease and hereditary ataxia. A brief introduction to the pathological substrate of cerebellar involvement is provided for each disease, followed by the review of MRI studies exploring structural and functional cerebellar abnormalities and by a discussion of the clinical relevance of MRI measures of cerebellar damage in terms of both clinical status and cognitive performance.

PMID: 29104740 [PubMed]

Altered function but not structure of the amygdala in nicotine-dependent individuals.

Tue, 11/07/2017 - 12:00
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Altered function but not structure of the amygdala in nicotine-dependent individuals.

Neuropsychologia. 2017 Nov 02;:

Authors: Shen Z, Huang P, Wang C, Qian W, Luo X, Guan X, Qiu T, Yang Y, Zhang M

Abstract
Tobacco use disorder is frequently comorbid with emotional disorders, each exerting reciprocal influence on the other. As an important hub for emotional processing, amygdala may also play a critical role in tobacco addiction. Therefore, we aimed to investigate the volume and spontaneous activity of the amygdala in nicotine-dependent individuals and their relationships with cigarette use. A total of 84 smokers (aged 22-54 years) and 41 nonsmokers (aged 26-56 years) were enrolled in the present study. 3D-T1 weighted images and resting-state fMRI images were acquired from all participants. We used ROI-wise volume, fractional amplitude of low frequency fluctuation (fALFF) and resting-state functional connectivity (FC) to assess structural and functional changes of the amygdala in the smokers. There was no significant difference between smokers and nonsmokers on amygdala volume (p>0.05). When compared to nonsmokers, increased fALFF in the right amygdala was observed in smokers (p=0.024). In addition, increased FC between the left amygdala and the right precuneus and decreased FC between the right amygdala and the right orbitofrontal cortex (OFC) was found in smokers. In smokers, these amygdala measures did not correlate with any measures of cigarette use. The results revealed that the amygdala function but not volume was affected in nicotine addiction. When considering the fALFF and FC results, we propose that the OFC top-down control may regulate the amygdala activity in nicotine addicts. The pattern of amygdala-based FC in smokers revealed in our study may provide new information about the brain circuitry of tobacco dependence.

PMID: 29104080 [PubMed - as supplied by publisher]

Acute effects of vortioxetine and duloxetine on resting-state functional connectivity in the awake rat.

Tue, 11/07/2017 - 12:00
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Acute effects of vortioxetine and duloxetine on resting-state functional connectivity in the awake rat.

Neuropharmacology. 2017 Nov 02;:

Authors: Pérez PD, Ma Z, Hamilton C, Sánchez C, Mørk A, Pehrson AL, Bundgaard C, Zhang N

Abstract
The antidepressant vortioxetine exerts its effects via modulation of several serotonin (5-HT) receptors and inhibition of the 5-HT transporter (SERT). Additionally, vortioxetine has beneficial effects on aspects of cognitive dysfunction in depressed patients. However, a global examination of the drug effect on brain network connectivity is still missing. Here we compared the effects of vortioxetine and a serotonin norepinephrine reuptake inhibitor, duloxetine, on resting-state functional connectivity (RSFC) across the whole brain in awake rats using a combination of pharmacological and awake animal resting-state functional magnetic resonance imaging (rsfMRI) techniques. Our data showed that vortioxetine and duloxetine affected different inter-areal connections with limited overlap, indicating that in addition to different primary target profiles, these two antidepressants have distinct mechanisms of action at the systems level. Further, our data suggest that vortioxetine can affect specific brain areas with distinct 5-HT receptor expression profiles. Taken together, this study demonstrates that the awake animal fMRI approach provides a powerful tool to elucidate the effects of drugs on the brain with high spatial specificity and a global field of view. This capability is valuable to understand how different drugs affect the systems-level brain function, and provides important guidance to dissect specific brain regions and connections for further detailed mechanistic studies. This study also highlights the translational opportunity of the awake animal fMRI approach between preclinical results and human studies.

PMID: 29104073 [PubMed - as supplied by publisher]

Cognitive and behavioral comorbidities in Rolandic epilepsy and their relation with default mode network's functional connectivity and organization.

Tue, 11/07/2017 - 12:00
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Cognitive and behavioral comorbidities in Rolandic epilepsy and their relation with default mode network's functional connectivity and organization.

Epilepsy Behav. 2017 Nov 02;:

Authors: Ofer I, Jacobs J, Jaiser N, Akin B, Hennig J, Schulze-Bonhage A, LeVan P

Abstract
OBJECTIVE: Rolandic epilepsy (RE) is characterized by typical interictal-electroencephalogram (EEG) patterns mainly localized in centrotemporal and parietooccipital areas. An aberrant intrinsic organization of the default mode network (DMN) due to repeated disturbances from spike-generating areas may be able to account for specific cognitive deficits and behavioral problems in RE. The aim of the present study was to investigate cognitive development (CD) and socioemotional development (SED) in patients with RE during active disease in relation to DMN connectivity and network topology.
METHODS: In 10 children with RE and active EEG, CD was assessed using the Wechsler Intelligence Scale for Children-IV (WISC-IV); SED was assessed using the Fünf-Faktoren-Fragebogen für Kinder (FFFK), a Big-Five inventory for the assessment of personality traits in children. Functional connectivity (FC) in the DMN was determined from a 15-minute resting state functional magnetic resonance imaging (fMRI), and network properties were calculated using standard graph-theoretical measures.
RESULTS: More severe deficits of verbal abilities tended to be associated with an earlier age at epilepsy onset, but were not directly related to the number of seizures and disease duration. Nonetheless, at the network level, disease duration was associated with alterations of the efficiency and centrality of parietal network nodes and midline structures. Particularly, centrality of the left inferior parietal lobe (IPL) was found to be linked with CD. Reduced centrality of the left IPL and alterations supporting a rather segregated processing within DMN's subsystems was associated with a more favorable CD. A more complicated SED was associated with high seizure frequency and long disease duration, and revealed links with a less favorable CD.
SIGNIFICANCE: An impaired CD and - because of their interrelation - SED might be mediated by a common pathomechanism reflected in an aberrant organization, and thus, a potential functional deficit of the DMN. A functional segregation of (left) parietal network nodes from the DMN and a rather segregated processing mode within the DMN might have positive implications/protective value for CD in patients with RE.

PMID: 29103838 [PubMed - as supplied by publisher]

Low frequency fluctuation of brain spontaneous activity and obsessive-compulsive symptoms in a large school-age sample.

Mon, 11/06/2017 - 17:00

Low frequency fluctuation of brain spontaneous activity and obsessive-compulsive symptoms in a large school-age sample.

J Psychiatr Res. 2017 Oct 16;96:224-230

Authors: Hoexter MQ, Biazoli CE, Alvarenga PG, Batistuzzo MC, Salum GA, Gadelha A, Pan PM, Anés M, Mancini-Martins L, Moura LM, Soriano-Mas C, Del' Aquilla MAG, Amaro E, Rohde LA, Jackowski AP, Bressan RA, Miguel EC, do Rosario MC, Sato JR

Abstract
BACKGROUND: The present study was designed to explore alterations in brain dynamics at rest that are associated with Obsessive Compulsive Symptoms (OCS) in childhood by measuring low frequency fluctuation of spontaneous brain activity in a large school community sample from a developing country.
METHOD: Resting state functional magnetic resonance imaging data were collected in a sample of 655 children and adolescents (6-15 years old) from the brazilian 'High Risk Cohort Study for Psychiatric Disorders (HRC)'. OCS were assessed using items from the Compulsion and Obsessions section of the Development and Well-Being Assessment (DAWBA). The correlation between the fractional amplitude of low frequency fluctuations (fALFF) and the number of OCS were explored by using a general linear model, considering fALFF as response variable, OCS score as regressor and age, gender and site as nuisance variables.
RESULTS: The number of OCS was positively correlated with the fALFF coefficients at the right sensorimotor cortex (pre-motor, primary motor cortex and post-central gyrus) and negatively correlated with the fALFF coefficients at the insula/superior temporal gyrus of both hemispheres. Our results were specific to OCS and not due to associations with overall psychopathology.
CONCLUSIONS: Our results suggest that brain spontaneous activity at rest in the sensorimotor and insular/superior-temporal cortices may be involved in OCS in children. These findings need independent replication and future studies should determine whether brain spontaneous activity changes within these regions might be predictors of risk for obsessive-compulsive disorder latter in life.

PMID: 29102817 [PubMed - as supplied by publisher]

Double temporal sparsity based accelerated reconstruction of compressively sensed resting-state fMRI.

Sun, 11/05/2017 - 16:00
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Double temporal sparsity based accelerated reconstruction of compressively sensed resting-state fMRI.

Comput Biol Med. 2017 Oct 29;91:255-266

Authors: Aggarwal P, Gupta A

Abstract
A number of reconstruction methods have been proposed recently for accelerated functional Magnetic Resonance Imaging (fMRI) data collection. However, existing methods suffer with the challenge of greater artifacts at high acceleration factors. This paper addresses the issue of accelerating fMRI collection via undersampled k-space measurements combined with the proposed method based on l(1)-l(1) norm constraints, wherein we impose first l(1)-norm sparsity on the voxel time series (temporal data) in the transformed domain and the second l(1)-norm sparsity on the successive difference of the same temporal data. Hence, we name the proposed method as Double Temporal Sparsity based Reconstruction (DTSR) method. The robustness of the proposed DTSR method has been thoroughly evaluated both at the subject level and at the group level on real fMRI data. Results are presented at various acceleration factors. Quantitative analysis in terms of Peak Signal-to-Noise Ratio (PSNR) and other metrics, and qualitative analysis in terms of reproducibility of brain Resting State Networks (RSNs) demonstrate that the proposed method is accurate and robust. In addition, the proposed DTSR method preserves brain networks that are important for studying fMRI data. Compared to the existing methods, the DTSR method shows promising potential with an improvement of 10-12 dB in PSNR with acceleration factors upto 3.5 on resting state fMRI data. Simulation results on real data demonstrate that DTSR method can be used to acquire accelerated fMRI with accurate detection of RSNs.

PMID: 29101794 [PubMed - as supplied by publisher]

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