New resting-state fMRI related studies at PubMed

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Common and distinct neural activities in frontoparietal network in first-episode bipolar disorder and major depressive disorder: Preliminary findings from a follow-up resting state fMRI study.

3 hours 4 min ago
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Common and distinct neural activities in frontoparietal network in first-episode bipolar disorder and major depressive disorder: Preliminary findings from a follow-up resting state fMRI study.

J Affect Disord. 2019 Sep 12;260:653-659

Authors: Jiang X, Fu S, Yin Z, Kang J, Wang X, Zhou Y, Wei S, Wu F, Kong L, Wang F, Tang Y

Abstract
BACKGROUND: It is difficult to distinguish bipolar disorder (BD) from major depressive disorder (MDD), especially with the initial depressive episode. In this study, we compared neural activities of BD and MDD patients during the first-episode (FE) to investigate common and distinct neural activities and further explore predictive indicators in the two diseases.
METHODS: FE-MDD patients were performed resting state functional magnetic resonance imaging and followed up after scanning. After follow-up, FE-MDD patients were regrouped into FE-BD and FE-MDD patients. The study included 24 FE-BD patients, 28 FE-MDD patients, and 30 age- and sex-matched healthy controls (HC) to investigate neural activities with regional homogeneity (ReHo) analysis among the 3 groups.
RESULTS: Compared to HC, FE-BD patients displayed significantly higher ReHo values in the superior frontal gyrus, the medial superior frontal gyrus within right-side cerebral hemisphere than FE-MDD patients and HC. Compared to HC, FE-BD and FE-MDD patients displayed significant decreased ReHo values in the paracentral lobule, the precuneus and the median cingulate and paracingulate gyrus within bilateral cerebral hemisphere, and the postcentral gyrus and the precentral gyrus within the right-side. FE-BD displayed significant lower ReHo values than FE-MDD patients in these regions.
LIMITATIONS: The potential effects of medicine, age, course of disease and handedness on results could not be ignored.
CONCLUSIONS: Abnormal neural activities of frontoparietal network may provide common and distinct markers to affective disorders and scientific basis for further prediction researches of affective disorders.

PMID: 31542559 [PubMed - as supplied by publisher]

Altered dynamic functional connectivity in weakly-connected state in major depressive disorder.

Sun, 09/22/2019 - 11:40
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Altered dynamic functional connectivity in weakly-connected state in major depressive disorder.

Clin Neurophysiol. 2019 Aug 23;130(11):2096-2104

Authors: Yao Z, Shi J, Zhang Z, Zheng W, Hu T, Li Y, Yu Y, Zhang Z, Fu Y, Zou Y, Zhang W, Wu X, Hu B

Abstract
OBJECTIVE: Major depressive disorder (MDD) is accompanied by abnormal changes in dynamic functional connectivity (FC) among brain regions. The aim of this study is to investigate whether the abnormalities of dynamic FC in MDD are state-dependent (related to a specific connectivity state).
METHODS: We performed time-varying connectivity analysis on resting-state functional magnetic resonance imaging (rs-fMRI) of 49 MDD patients and 54 matched healthy controls (HCs). FC differences between groups in each connectivity state were analyzed and associations between disease severity and dynamics of aberrant FC were explored.
RESULTS: Two distinct connectivity states (i.e., weakly-connected and strongly-connected state) were identified. Compared to HCs, MDD patients were associated with increased mean dwell time and decreased FC between and within subnetworks in the weakly-connected state. Dynamics of reduced FC between cognitive control network and default mode network as well as within cognitive control network predicted individual differences in depression symptom severity.
CONCLUSIONS: Our findings suggested that the MDD-caused FC alterations mostly appeared in the weakly-connected state, which might contribute to clinical diagnosis of MDD.
SIGNIFICANCE: These findings provide new perspectives for understanding the state-dependent neurophysiological mechanisms in MDD.

PMID: 31541987 [PubMed - as supplied by publisher]

Topological reorganization of the default mode network in patients with poststroke depressive symptoms: A resting-state fMRI study.

Sat, 09/21/2019 - 10:40

Topological reorganization of the default mode network in patients with poststroke depressive symptoms: A resting-state fMRI study.

J Affect Disord. 2019 Sep 11;260:557-568

Authors: Liang Y, Yao YC, Zhao L, Shi L, Chen YK, Mok VC, Ungvari GS, Chu WC, Tang WK

Abstract
OBJECTIVE: This study mapped the topological configuration of the default mode network (DMN) in patients with depressive symptoms after acute ischemic stroke.
METHODS: The study sample comprised 63 patients: 36 with poststroke depressive symptoms (PSD) and 37 without PSD matched according to age, gender and the severity of stroke. PSD was defined by a cutoff of ≥ 7 on the 15-item Geriatric Depression Scale (GDS). Resting-state functional magnetic resonance imaging (fMRI) was used to examine functional connectivity (FC) to reconstruct the DMN. Network based statistics estimated the FC differences of the DMN between the PSD and non-PSD groups. Graph theoretical approaches were used to characterize the topological properties of this network.
RESULTS: The study sample mainly comprised patients with mild to moderate stroke. A widespread hyper-connected configuration of the functional DMN was characterized in PSD group. The orbital frontal, dorsolateral prefrontal, dorsal medial prefrontal and, ventromedial prefrontal corticis, the middle temporal gyrus and the inferior parietal lobule were the functional hubs related to PSD. The nodal topology in inferior parietal lobule and superior frontal gyrus, overlapping with dorsal medial prefrontal and, ventromedial prefrontal cortices, tended to be functionally integrated in patients with PSD. After False Discovery Rate correction, no significant difference between the PSD and non-PSD groups was found with respect to the global and nodal metrics of the DMN. However, the correlations between these altered network metrics and severity of PSD were lacking.
LIMITATIONS: The diagnosis of PSD was based on the GDS score rather than established with a structured clinical interview.
CONCLUSIONS: The DMN in PSD was functionally integrated and more specialized in some core hubs such as the inferior parietal lobule and dorsal prefrontal cortex. The configuration of the subnetwork like DMN may be more essential in the pathogenesis of PSD than single stroke lesions.

PMID: 31539693 [PubMed - as supplied by publisher]

Connectivity between the anterior insula and dorsolateral prefrontal cortex links early symptom improvement to treatment response.

Sat, 09/21/2019 - 10:40

Connectivity between the anterior insula and dorsolateral prefrontal cortex links early symptom improvement to treatment response.

J Affect Disord. 2019 Sep 09;260:490-497

Authors: Yuan H, Zhu X, Tang W, Cai Y, Shi S, Luo Q

Abstract
BACKGROUND: Early improvement (EI) following treatment with antidepressants is a widely reported predictor to the treatment response. This study aimed to identify the resting-state functional connectivity (rs-FC) and its related clinical features that link the treatment response at the time of EI.
METHODS: This study included 23 first-episode treatment-naive patients with MDD. After 2 weeks of antidepressant treatment, these patients received 3.0 Tesla resting-state functional magnetic resonance imaging scanning and were subgrouped into an EI group (N = 13) and a non-EI group (N = 10). Using the anterior insula (rAI) as a seed region, this study identified the rs-FC that were associated with both EI and the treatment response at week 12, and further tested the associations of the identified rs-FC with either the clinical features or the early symptom improvement.
RESULTS: Rs-FC between rAI and the left dorsolateral prefrontal cortex (dlPFC) was associated with EI (t21 = -6.091, p = 0.022 after FDR correction for multiple comparisons). This rs-FC was also associated with an interaction between EI and the treatment response at the week 12 (t21 = -5.361, p = 6.37e-5). Moreover, among the clinical features, this rs-FC was associated with the early symptom improvement in the insomnia, somatic symptoms, and anxiety symptoms, and these early symptom improvements were associated with the treatment response.
CONCLUSION: Rs-FC between the rAI and the left dlPFC played a crucial role in the early antidepressant effect, which linked the treatment response. The early treatment effect relating to rAI may represent an early symptom improvement in self-perceptual anxiety, somatic symptoms and insomnia.

PMID: 31539685 [PubMed - as supplied by publisher]

Elucidating the putative link between prefrontal neurotransmission, functional connectivity, and affective symptoms in irritable bowel syndrome.

Sat, 09/21/2019 - 10:40
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Elucidating the putative link between prefrontal neurotransmission, functional connectivity, and affective symptoms in irritable bowel syndrome.

Sci Rep. 2019 Sep 19;9(1):13590

Authors: Icenhour A, Tapper S, Bednarska O, Witt ST, Tisell A, Lundberg P, Elsenbruch S, Walter S

Abstract
Altered neural mechanisms are well-acknowledged in irritable bowel syndrome (IBS), a disorder of brain-gut-communication highly comorbid with anxiety and depression. As a key hub in corticolimbic inhibition, medial prefrontal cortex (mPFC) may be involved in disturbed emotion regulation in IBS. However, aberrant mPFC excitatory and inhibitory neurotransmission potentially contributing to psychological symptoms in IBS remains unknown. Using quantitative magnetic resonance spectroscopy (qMRS), we compared mPFC glutamate + glutamine (Glx) and γ-aminobutyric acid (GABA+) concentrations in 64 women with IBS and 32 age-matched healthy women (HCs) and investigated their association with anxiety and depression in correlational and subgroup analyses. Applying functional magnetic resonance imaging (fMRI), we explored whether altered neurotransmission was paralleled by aberrant mPFC resting-state functional connectivity (FC). IBS patients did not differ from HCs with respect to mPFC GABA+ or Glx levels. Anxiety was positively associated with mPFC GABA+ concentrations in IBS, whereas Glx was unrelated to psychological or gastrointestinal symptoms. Subgroup comparisons of patients with high or low anxiety symptom severity and HCs revealed increased GABA+ in patients with high symptom severity, and lower mPFC FC with adjacent anterior cingulate cortex (ACC), a crucial region of emotion modulation. Our findings provide novel evidence that altered prefrontal inhibitory neurotransmission may be linked to anxiety in IBS.

PMID: 31537890 [PubMed - in process]

A Multi-Domain Connectome Convolutional Neural Network for Identifying Schizophrenia from EEG Connectivity Patterns.

Fri, 09/20/2019 - 15:40
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A Multi-Domain Connectome Convolutional Neural Network for Identifying Schizophrenia from EEG Connectivity Patterns.

IEEE J Biomed Health Inform. 2019 Sep 13;:

Authors: Phang CR, Noman FM, Hussain H, Ting CM, Ombao H

Abstract
OBJECTIVE: We exploit altered patterns in brain functional connectivity as features for automatic discriminative analysis of neuropsychiatric patients. Deep learning methods have been introduced to functional network classification only very recently for fMRI, and the proposed architectures essentially focused on a single type of connectivity measure.
METHODS: We propose a deep convolutional neural network (CNN) framework for classification of electroencephalogram (EEG)-derived brain connectome in schizophrenia (SZ). To capture complementary aspects of disrupted connectivity in SZ, we explore combination of various connectivity features consisting of time and frequency-domain metrics of effective connectivity based on vector autoregressive model and partial directed coherence, and complex network measures of network topology. We design a novel multi-domain connectome CNN (MDC-CNN) based on a parallel ensemble of 1D and 2D CNNs to integrate the features from various domains and dimensions using different fusion strategies. We also consider an extension to dynamic brain connectivity using the recurrent neural networks.
RESULTS: Hierarchical latent representations learned by the multiple convolutional layers from EEG connectivity reveal apparent group differences between SZ and healthy controls (HC). Results on a large resting-state EEG dataset show that the proposed CNNs significantly outperform traditional support vector machine classifiers. The MDC-CNN with combined connectivity features further improves performance over single-domain CNNs using individual features, achieving remarkable accuracy of 91.69% with a decision-level fusion.
CONCLUSION: The proposed MDC-CNN by integrating information from diverse brain connectivity descriptors is able to accurately discriminate SZ from HC.
SIGNIFICANCE: The new framework is potentially useful for developing diagnostic tools for SZ and other disorders.

PMID: 31536026 [PubMed - as supplied by publisher]

The reorganization of resting-state brain networks associated with motor imagery training in chronic stroke patients.

Fri, 09/20/2019 - 15:40
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The reorganization of resting-state brain networks associated with motor imagery training in chronic stroke patients.

IEEE Trans Neural Syst Rehabil Eng. 2019 Sep 13;:

Authors: Wang H, Xu G, Wang X, Sun C, Zhu B, Fan M, Jia J, Guo X, Sun L

Abstract
A number of studies have suggested that motor imagery training (MIT) has a positive influence on the upper extremity motor recovery in stroke patients, but little is known about its neural basis. To investigate the cortical motor network plasticity after MIT, 34 chronic hemiplegic subjects with subcortical stroke were recruited and randomly allocated to either the conventional rehabilitation therapy (CRT) or the CRT+MIT. The patients were assessed with the upper limb section of Fugl-Meyer assessment Scale (FM-UL) and resting-state fMRI before and after the 4 weeks of treatment. Seed-based functional connectivity (FC) of the ipsilesional primary motor cortex (M1) and graph-theory based analysis were used to explore the relationships between the motor recovery and reorganization of motor networks. We found that the patients in the MIT group showed more improvement in the FM-UL scores compared with the CRT group. Both groups presented increased inter-hemispheric and decreased intra-hemispheric FC of the ipsilesional M1 after intervention. However, the MIT group showed increased FC of the ipsilesional M1 with the ipsilesional precentral and postcentral gyri, middle cingulate gyrus and supramarginal gyrus after intervention, while the CRT group showed decreased FC in these regions. In addition, the clustering coefficient was significantly increased in the MIT group but not in the CRT group, and the increment of clustering coefficient was significantly positively correlated with improvement of FM-UL scores. Therefore, MIT might contribute to the motor recovery in stroke patients through the following network reorganization, i.e., promoting the efficiency of regional neuronal communication and the reorganization of intrinsic FC of the ipsilesional M1 involving widely distributed motor network in both hemispheres.

PMID: 31536007 [PubMed - as supplied by publisher]

Aberrant brain network connectivity in presymptomatic and manifest Huntington's disease: A systematic review.

Thu, 09/19/2019 - 14:20
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Aberrant brain network connectivity in presymptomatic and manifest Huntington's disease: A systematic review.

Hum Brain Mapp. 2019 Sep 18;:

Authors: Pini L, Jacquemot C, Cagnin A, Meneghello F, Semenza C, Mantini D, Vallesi A

Abstract
Resting-state functional magnetic resonance imaging (rs-fMRI) has the potential to shed light on the pathophysiological mechanisms of Huntington's disease (HD), paving the way to new therapeutic interventions. A systematic literature review was conducted in three online databases according to PRISMA guidelines, using keywords for HD, functional connectivity, and rs-fMRI. We included studies investigating connectivity in presymptomatic (pre-HD) and manifest HD gene carriers compared to healthy controls, implementing seed-based connectivity, independent component analysis, regional property, and graph analysis approaches. Visual network showed reduced connectivity in manifest HD, while network/areas underpinning motor functions were consistently altered in both manifest HD and pre-HD, showing disease stage-dependent changes. Cognitive networks underlying executive and attentional functions showed divergent anterior-posterior alterations, possibly reflecting compensatory mechanisms. The involvement of these networks in pre-HD is still unclear. In conclusion, aberrant connectivity of the sensory-motor network is observed in the early stage of HD while, as pathology spreads, other networks might be affected, such as the visual and executive/attentional networks. Moreover, sensory-motor and executive networks exhibit hyper- and hypo-connectivity patterns following different spatiotemporal trajectories. These findings could potentially help to implement future huntingtin-lowering interventions.

PMID: 31532053 [PubMed - as supplied by publisher]

Ketamine effects on default mode network activity and vigilance: A randomized, placebo-controlled crossover simultaneous fMRI/EEG study.

Thu, 09/19/2019 - 14:20
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Ketamine effects on default mode network activity and vigilance: A randomized, placebo-controlled crossover simultaneous fMRI/EEG study.

Hum Brain Mapp. 2019 Sep 18;:

Authors: Zacharias N, Musso F, Müller F, Lammers F, Saleh A, London M, de Boer P, Winterer G

Abstract
In resting-state functional connectivity experiments, a steady state (of consciousness) is commonly supposed. However, recent research has shown that the resting state is a rather dynamic than a steady state. In particular, changes of vigilance appear to play a prominent role. Accordingly, it is critical to assess the state of vigilance when conducting pharmacodynamic studies with resting-state functional magnetic resonance imaging (fMRI) using drugs that are known to affect vigilance such as (subanesthetic) ketamine. In this study, we sought to clarify whether the previously described ketamine-induced prefrontal decrease of functional connectivity is related to diminished vigilance as assessed by electroencephalography (EEG). We conducted a randomized, double-blind, placebo-controlled crossover study with subanesthetic S-Ketamine in N = 24 healthy, young subjects by simultaneous acquisition of resting-state fMRI and EEG data. We conducted seed-based default mode network functional connectivity and EEG power spectrum analyses. After ketamine administration, decreased functional connectivity was found in medial prefrontal cortex whereas increased connectivities were observed in intraparietal cortices. In EEG, a shift of energy to slow (delta, theta) and fast (gamma) wave frequencies was seen in the ketamine condition. Frontal connectivity is negatively related to EEG gamma and theta activity while a positive relationship is found for parietal connectivity and EEG delta power. Our results suggest a direct relationship between ketamine-induced functional connectivity changes and the concomitant decrease of vigilance in EEG. The observed functional changes after ketamine administration may serve as surrogate end points and provide a neurophysiological framework, for example, for the antidepressant action of ketamine (trial name: 29JN1556, EudraCT Number: 2009-012399-28).

PMID: 31532029 [PubMed - as supplied by publisher]

Projection from the Anterior Cingulate Cortex to the Lateral Part of Mediodorsal Thalamus Modulates Vicarious Freezing Behavior.

Thu, 09/19/2019 - 14:20
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Projection from the Anterior Cingulate Cortex to the Lateral Part of Mediodorsal Thalamus Modulates Vicarious Freezing Behavior.

Neurosci Bull. 2019 Sep 17;:

Authors: Zheng C, Huang Y, Bo B, Wei L, Liang Z, Wang Z

Abstract
Emotional contagion, a primary form of empathy, is present in rodents. Among emotional contagion behaviors, social transmission of fear is the most studied. Here, we modified a paradigm used in previous studies to more robustly assess the social transmission of fear in rats that experienced foot-shock. We used resting-state functional magnetic resonance imaging to show that foot-shock experience enhances the regional connectivity of the anterior cingulate cortex (ACC). We found that lesioning the ACC specifically attenuated the vicarious freezing behavior of foot-shock-experienced observer rats. Furthermore, ablation of projections from the ACC to the mediodorsal thalamus (MDL) bilaterally delayed the vicarious freezing responses, and activation of these projections decreased the vicarious freezing responses. Overall, our results demonstrate that, in rats, the ACC modulates vicarious freezing behavior via a projection to the MDL and provide clues to understanding the mechanisms underlying empathic behavior in humans.

PMID: 31531804 [PubMed - as supplied by publisher]

Perturbations of language network connectivity in primary progressive aphasia.

Thu, 09/19/2019 - 14:20
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Perturbations of language network connectivity in primary progressive aphasia.

Cortex. 2019 Sep 09;:

Authors: Bonakdarpour B, Hurley RS, Wang AR, Fereira HR, Basu A, Chatrathi A, Guillaume K, Rogalski EJ, Mesulam MM

Abstract
Aphasias are caused by disruption in structural integrity and interconnectivity within a large-scale distributed language network. We investigated the distribution and behavioral consequences of altered functional connectivity in three variants of primary progressive aphasia (PPA). The goal was to clarify relationships among atrophy, resting connectivity, and the resulting behavioral changes in 73 PPA and 33 control participants. Three core regions of the left perisylvian language network: the inferior frontal gyrus (IFG), middle temporal gyrus (MTG), and anterior temporal lobe (ATL) were evaluated in agrammatic (PPA-G), logopenic (PPA-L), and semantic (PPA-S) PPA variants. All PPA groups showed decreased connectivity between IFG and MTG. The PPA-S group also showed additional loss of connectivity strength between ATL and the other language regions. Decreased connectivity between the IFG and MTG nodes in PPA-G remained significant even when controlled for the effect of atrophy. In the PPA group as a whole, IFG-MTG connectivity strength correlated with repetition and grammar scores, whereas MTG-ATL connectivity correlated with picture naming and single-word comprehension. There was no significant change in the connectivity of homologous regions in the right hemisphere. These results show that language impairments in PPA are associated with perturbations of functional connectivity within behaviorally concordant components of the language network. Altered connectivity in PPA may reflect not only the irreversible loss of cortical components indexed by atrophy, but also the dysfunction of remaining neurons.

PMID: 31530376 [PubMed - as supplied by publisher]

Maternal immune activation during pregnancy impacts on brain structure and function in the adult offspring.

Thu, 09/19/2019 - 14:20
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Maternal immune activation during pregnancy impacts on brain structure and function in the adult offspring.

Brain Behav Immun. 2019 Sep 14;:

Authors: Kreitz S, Zambon A, Ronovsky M, Budinsky L, Helbich TH, Sideromenos S, Ivan C, Konerth L, Wank I, Berger A, Pollak A, Hess A, Pollak DD

Abstract
Gestational infection constitutes a risk factor for the occurrence of psychiatric disorders in the offspring. Activation of the maternal immune system (MIA) with subsequent impact on the development of the fetal brain is considered to form the neurobiological basis for aberrant neural wiring and the psychiatric manifestations later in offspring life. The examination of validated animal models constitutes a premier resource. Here we used a mouse model of MIA based upon systemic treatment of pregnant mice with Poly(I:C) (polyriboinosinic-polyribocytidilic acid), for the unbiased and comprehensive analysis of the impact of MIA on adult offspring brain activity, morphometry, connectivity and function by a magnetic resonance imaging (MRI) approach. Overall lower neural activity, smaller brain regions and less effective fiber structure were observed for Poly(I:C) offspring compared to the control group. The corpus callosum was significantly smaller and presented with a disruption in myelin/ fiber structure in the MIA progeny. Subsequent resting-state functional MRI experiments demonstrated a paralleling dysfunctional interhemispheric connectivity. Additionally, while the overall flow of information was intact, cortico-limbic connectivity was hampered and limbic circuits revealed hyperconnectivity in Poly(I:C) offspring. Our study sheds new light on the impact of maternal infection during pregnancy on the offspring brain and identifies aberrant resting-state functional connectivity patterns as possible correlates of the behavioral phenotype with relevance for psychiatric disorders.

PMID: 31526827 [PubMed - as supplied by publisher]

Adolescent alcohol exposure decreases frontostriatal resting-state functional connectivity in adulthood.

Thu, 09/19/2019 - 14:20
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Adolescent alcohol exposure decreases frontostriatal resting-state functional connectivity in adulthood.

Addict Biol. 2018 03;23(2):810-823

Authors: Broadwater MA, Lee SH, Yu Y, Zhu H, Crews FT, Robinson DL, Shih YI

Abstract
Connectivity of the prefrontal cortex (PFC) matures through adolescence, coinciding with emergence of adult executive function and top-down inhibitory control over behavior. Alcohol exposure during this critical period of brain maturation may affect development of PFC and frontolimbic connectivity. Adult rats exposed to adolescent intermittent ethanol (AIE; 5 g/kg ethanol, 25 percent v/v in water, intragastrically, 2-day-on, 2-day-off, postnatal day 25-54) or water control underwent resting-state functional MRI to test the hypothesis that AIE induces persistent changes in frontolimbic functional connectivity under baseline and acute alcohol conditions (2 g/kg ethanol or saline, intraperitoneally administered during scanning). Data were acquired on a Bruker 9.4-T MR scanner with rats under dexmedetomidine sedation in combination with isoflurane. Frontolimbic network regions-of-interest for data analysis included PFC [prelimbic (PrL), infralimbic (IL), and orbitofrontal cortex (OFC) portions], nucleus accumbens (NAc), caudate putamen (CPu), dorsal hippocampus, ventral tegmental area, amygdala, and somatosensory forelimb used as a control region. AIE decreased baseline resting-state connectivity between PFC subregions (PrL-IL and IL-OFC) and between PFC-striatal regions (PrL-NAc, IL-CPu, IL-NAc, OFC-CPu, and OFC-NAc). Acute ethanol induced negative blood-oxygen-level-dependent changes within all regions of interest examined, along with significant increases in functional connectivity in control, but not AIE animals. Together, these data support the hypothesis that binge-like adolescent alcohol exposure causes persistent decreases in baseline frontolimbic (particularly frontostriatal) connectivity and alters sensitivity to acute ethanol-induced increases in functional connectivity in adulthood.

PMID: 28691248 [PubMed - indexed for MEDLINE]

Altered interhemispheric resting-state functional connectivity in young male smokers.

Thu, 09/19/2019 - 14:20
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Altered interhemispheric resting-state functional connectivity in young male smokers.

Addict Biol. 2018 03;23(2):772-780

Authors: Yu D, Yuan K, Bi Y, Luo L, Zhai J, Liu B, Li Y, Cheng J, Guan Y, Xue T, Bu L, Su S, Ma Y, Qin W, Tian J, Lu X

Abstract
With the help of advanced neuroimaging approaches, previous studies revealed structural and functional brain changes in smokers compared with healthy non-smokers. Homotopic resting-state functional connectivity between the corresponding regions in cerebral hemispheres may help us to deduce the changes of functional coordination in the whole brain of young male smokers. Functional homotopy reflects an essential aspect of brain function and communication between the left and right cerebral hemispheres, which is important for the integrity of brain function. However, few studies used voxel mirrored homotopic connectivity (VMHC) method to investigate the changes of homotopic connectivity in young male smokers. Twenty-seven young male smokers and 27 matched healthy male non-smokers were recruited in our study. Compared with healthy male non-smokers, young male smokers showed decreased VMHC values in the insula and putamen, and increased VMHC values in the prefrontal cortex. Correlation analysis demonstrated that there were significant positive correlations between the average VMHC values of the prefrontal cortex and pack-years in young male smokers. In addition, significant negative correlation was found between the average VMHC values in the insula and pack-years. Our results revealed the disrupted homotopic resting-state functional connectivity in young male smokers. The novel findings may extend our understanding of smoking.

PMID: 28474806 [PubMed - indexed for MEDLINE]

Estimating repetitive spatiotemporal patterns from many subjects' resting-state fMRIs.

Tue, 09/17/2019 - 12:00

Estimating repetitive spatiotemporal patterns from many subjects' resting-state fMRIs.

Neuroimage. 2019 Sep 13;:116182

Authors: Takeda Y, Itahashi T, Sato MA, Yamashita O

Abstract
Recently, we proposed a method to estimate repetitive spatiotemporal patterns from resting-state brain activity data (SpatioTemporal Pattern estimation, STeP) (Takeda et al., 2016). From such resting-state data as functional MRI (fMRI), STeP can estimate several spatiotemporal patterns and their onsets even if they are overlapping. Nowadays, a growing number of resting-state data are publicly available from such databases as the Autism Brain Imaging Data Exchange (ABIDE), which promote a better understanding of resting-state brain activities. In this study, we extend STeP to make it applicable to such big databases, thus proposing the method we call BigSTeP. From many subjects' resting-state data, BigSTeP estimates spatiotemporal patterns that are common across subjects (common spatiotemporal patterns) as well as the corresponding spatiotemporal patterns in each subject (subject-specific spatiotemporal patterns). After verifying the performance of BigSTeP by simulation tests, we applied it to over 1,000 subjects' resting-state fMRIs (rsfMRIs) obtained from ABIDE I. This revealed two common spatiotemporal patterns and the corresponding subject-specific spatiotemporal patterns. The common spatiotemporal patterns included spatial patterns resembling the default mode (DMN), sensorimotor, auditory, and visual networks, suggesting that these networks are time-locked with each other. We compared the subject-specific spatiotemporal patterns between autism spectrum disorder (ASD) and typically developed (TD) groups. As a result, significant differences were concentrated at a specific time in a pattern, when the DMN exhibited large positive activity. This suggests that the differences are context-dependent, that is, the differences in fMRI activities between ASDs and TDs do not always occur during the resting state but tend to occur when the DMN exhibits large positive activity. All of these results demonstrate the usefulness of BigSTeP in extracting inspiring hypotheses from big databases in a data-driven way.

PMID: 31525496 [PubMed - as supplied by publisher]

Capturing the Forest But Missing the Trees: Microstates Inadequate for Characterizing Shorter-Scale EEG Dynamics.

Tue, 09/17/2019 - 12:00

Capturing the Forest But Missing the Trees: Microstates Inadequate for Characterizing Shorter-Scale EEG Dynamics.

Neural Comput. 2019 Sep 16;:1-35

Authors: Shaw SB, Dhindsa K, Reilly JP, Becker S

Abstract
The brain is known to be active even when not performing any overt cognitive tasks, and often it engages in involuntary mind wandering. This resting state has been extensively characterized in terms of fMRI-derived brain networks. However, an alternate method has recently gained popularity: EEG microstate analysis. Proponents of microstates postulate that the brain discontinuously switches between four quasi-stable states defined by specific EEG scalp topologies at peaks in the global field potential (GFP). These microstates are thought to be "atoms of thought," involved with visual, auditory, salience, and attention processing. However, this method makes some major assumptions by excluding EEG data outside the GFP peaks and then clustering the EEG scalp topologies at the GFP peaks, assuming that only one microstate is active at any given time. This study explores the evidence surrounding these assumptions by studying the temporal dynamics of microstates and its clustering space using tools from dynamical systems analysis, fractal, and chaos theory to highlight the shortcomings in microstate analysis. The results show evidence of complex and chaotic EEG dynamics outside the GFP peaks, which is being missed by microstate analysis. Furthermore, the winner-takes-all approach of only one microstate being active at a time is found to be inadequate since the dynamic EEG scalp topology does not always resemble that of the assigned microstate, and there is competition among the different microstate classes. Finally, clustering space analysis shows that the four microstates do not cluster into four distinct and separable clusters. Taken collectively, these results show that the discontinuous description of EEG microstates is inadequate when looking at nonstationary short-scale EEG dynamics.

PMID: 31525310 [PubMed - as supplied by publisher]

Cognitive remediation therapy modulates intrinsic neural activity in patients with major depression.

Tue, 09/17/2019 - 12:00

Cognitive remediation therapy modulates intrinsic neural activity in patients with major depression.

Psychol Med. 2019 Sep 16;:1-11

Authors: Schneider I, Schmitgen MM, Bach C, Listunova L, Kienzle J, Sambataro F, Depping MS, Kubera KM, Roesch-Ely D, Wolf RC

Abstract
BACKGROUND: Cognitive impairment is a core feature of major depressive disorder (MDD). Cognitive remediation may improve cognition in MDD, yet so far, the underlying neural mechanisms are unclear. This study investigated changes in intrinsic neural activity in MDD after a cognitive remediation trial.
METHODS: In a longitudinal design, 20 patients with MDD and pronounced cognitive deficits and 18 healthy controls (HC) were examined using resting-state functional magnetic resonance imaging. MDD patients received structured cognitive remediation therapy (CRT) over 5 weeks. The whole-brain fractional amplitude of low-frequency fluctuations was computed before the first and after the last training session. Univariate methods were used to address regionally-specific effects, and a multivariate data analysis strategy was employed to investigate functional network strength (FNS).
RESULTS: MDD patients significantly improved in cognitive function after CRT. Baseline comparisons revealed increased right caudate activity and reduced activity in the left frontal cortex, parietal lobule, insula, and precuneus in MDD compared to HC. In patients, reduced FNS was found in a bilateral prefrontal system at baseline (p < 0.05, uncorrected). In MDD, intrinsic neural activity increased in right inferior frontal gyrus after CRT (p < 0.05, small volume corrected). Left inferior parietal lobule, left insula, left precuneus, and right caudate activity showed associations with cognitive improvement (p < 0.05, uncorrected). Prefrontal network strength increased in patients after CRT, but this increase was not associated with improved cognitive performance.
CONCLUSIONS: Our findings support the role of intrinsic neural activity of the prefrontal cortex as a possible mediator of cognitive improvement following CRT in MDD.

PMID: 31524112 [PubMed - as supplied by publisher]

Reduced connectivity in anterior cingulate cortex as an early predictor for treatment response in drug-naive, first-episode schizophrenia: A global-brain functional connectivity analysis.

Tue, 09/17/2019 - 12:00
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Reduced connectivity in anterior cingulate cortex as an early predictor for treatment response in drug-naive, first-episode schizophrenia: A global-brain functional connectivity analysis.

Schizophr Res. 2019 Sep 12;:

Authors: Li H, Ou Y, Liu F, Chen J, Zhao J, Guo W, Fan X

Abstract
BACKGROUND: Antipsychotic medications may have acute effect on brain functional connectivity (FC) after only a few days of treatment. It is unclear if early changes in FC can predict treatment response in patients with schizophrenia.
METHODS: The study included 32 patients with drug-naive, first-episode schizophrenia and 32 healthy controls. Resting-state functional magnetic resonance imaging was obtained from the patients at two time-points (pre-treatment baseline and 1 week after treatment) and healthy controls at baseline. Patients were treated with olanzapine for 8 weeks, and clinical symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS) at three time points (baseline, 1 week and 8 weeks after treatment). Imaging data were analyzed using global-brain FC (GFC) and support vector regression (SVR).
RESULTS: At baseline, an increased GFC was observed in bilateral anterior cingulate cortex (ACC) in patients compared with healthy controls. After 1 week of olanzapine treatment, patients showed decreased GFC in bilateral ACC compared to the baseline values. SVR analysis suggested a positive relationship between GFC changes in bilateral ACC at week 1 and improvement in negative symptoms at week 8 (r = 0.957, p < 0.001).
CONCLUSION: An early decrease in GFC in bilateral ACC may serve as a predictor for treatment response in patients with schizophrenia. If further confirmed, our finding may be able to help clinicians decide, during the early treatment course, whether the patient should stay on the chosen antipsychotic medication or switch to a different one.

PMID: 31522869 [PubMed - as supplied by publisher]

3D-CNN based discrimination of schizophrenia using resting-state fMRI.

Mon, 09/16/2019 - 11:00

3D-CNN based discrimination of schizophrenia using resting-state fMRI.

Artif Intell Med. 2019 Jul;98:10-17

Authors: Qureshi MNI, Oh J, Lee B

Abstract
MOTIVATION: This study reports a framework to discriminate patients with schizophrenia and normal healthy control subjects, based on magnetic resonance imaging (MRI) of the brain. Resting-state functional MRI data from a total of 144 subjects (72 patients with schizophrenia and 72 healthy controls) was obtained from a publicly available dataset using a three-dimensional convolution neural network 3D-CNN based deep learning classification framework and ICA based features.
RESULTS: We achieved 98.09 ± 1.01% ten-fold cross-validated classification accuracy with a p-value < 0.001 and an area under the curve (AUC) of 0.9982 ± 0.015. In addition, differences in functional connectivity between the two groups were statistically analyzed across multiple resting-state networks. The disconnection between the visual and frontal network was prominent in patients, while they showed higher connectivity between the default mode network and other task-positive/ cerebellar networks. These ICA functional network maps served as highly discriminative three-dimensional imaging features for the discrimination of schizophrenia in this study.
CONCLUSION: Due to the very high AUC, this research with more validation on the cross diagnosis and publicly available dataset, may be translated in future as an adjunct tool to assist clinicians in the initial screening of schizophrenia.

PMID: 31521248 [PubMed - in process]

Alterations in basal ganglia-cerebello-thalamo-cortical connectivity and whole brain functional network topology in Tourette's syndrome.

Sat, 09/14/2019 - 15:00
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Alterations in basal ganglia-cerebello-thalamo-cortical connectivity and whole brain functional network topology in Tourette's syndrome.

Neuroimage Clin. 2019 Sep 03;24:101998

Authors: Ramkiran S, Heidemeyer L, Gaebler A, Shah NJ, Neuner I

Abstract
Tourette Syndrome (TS) is a neuropsychiatric disorder characterized by the presence of motor and vocal tics. Major pathophysiological theories posit a dysfunction of the cortico-striato-thalamo-cortical circuits as being a representative hallmark of the disease. Recent evidence suggests a more widespread dysfunction of brain networks in TS including the cerebellum and going even beyond classic motor pathways. In order to characterize brain network dysfunction in TS, in this study we investigated functional and effective-like connectivity as well as topological changes of basal ganglia-thalamo-cortical and cortico-cerebellar brain networks. We collected resting-state fMRI data from 28 TS patients (age: 32 ± 11 years) and 28 age-matched, healthy controls (age: 31 ± 9 years). Region of interest based (ROI-ROI) bivariate correlation and ROI-ROI bivariate regression were employed as measures of functional and effective-like connectivity, respectively. Graph theoretical measures of centrality (degree, cost, betweenness centrality), functional segregation (clustering coefficient, local efficiency) and functional integration (average path length, global efficiency) were used to assess topological brain network changes. In this study, TS patients exhibited increased basal ganglia-cortical and thalamo-cortical connectivity, reduced cortico-cerebellar connectivity, and an increase in parallel communication through the basal ganglia, thalamus and cerebellum (increased global efficiency). Additionally, we observed a reduction in serial information transfer (reduction in average path length) within the default mode and the salience network. In summary, our findings show that TS is characterized by increased connectivity and functional integration of multiple basal ganglia-thalamo-cortical circuits, suggesting a predominance of excitatory neurotransmission and a lack of brain maturation. Moreover, topological changes of cortico-cerebellar and brain networks involved in interoception may be underestimated neural correlates of tics and the crucial premonitory urge feeling.

PMID: 31518769 [PubMed - as supplied by publisher]

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