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Disrupted Spontaneous Neural Activity Related to Cognitive Impairment in Postpartum Women.

Sat, 05/19/2018 - 14:40
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Disrupted Spontaneous Neural Activity Related to Cognitive Impairment in Postpartum Women.

Front Psychol. 2018;9:624

Authors: Zheng JX, Chen YC, Chen H, Jiang L, Bo F, Feng Y, Tang WW, Yin X, Gu JP

Abstract
Purpose: Prior research has demonstrated that the postpartum period is associated with an increased risk of cognitive impairment. This study aims to investigate whether disrupted spontaneous neural activity exists in postpartum women without depression using resting-state functional magnetic resonance imaging (rs-fMRI) and to detect the relationship between these abnormalities and cognitive impairment. Materials and Methods: Postpartum women (n = 22) were compared with age- and education-matched nulliparous women (n = 23) using rs-fMRI. We calculated the amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo) values to evaluate spontaneous neural activity and detect the relationship between rs-fMRI data and cognitive performance. Results: Relative to nulliparous women, postpartum women had significantly decreased ALFF and ReHo values primarily in the left posterior cingulate cortex (PCC) and prefrontal cortex and increased ALFF values in left cerebellar posterior lobe. We found a positive correlation between the ALFF and ReHo values in the PCC and the complex figure test (CFT)-delayed scores in postpartum women (r = 0.693, p = 0.001; r = 0.569, p = 0.011, respectively). Moreover, the clock-drawing test (CDT) scores showed positive correlations with the ALFF and ReHo values in the right superior frontal gyrus (SFG; r = 0.492, p = 0.033; r = 0.517, p = 0.023, respectively). Conclusion: Our combined ALFF and ReHo analyses revealed decreased spontaneous neural activity, mainly in the PCC and prefrontal cortex, which was correlated with specific impaired cognitive functioning in postpartum women. This study may elucidate the neurophysiological mechanisms underlying postpartum cognitive impairment and enhance our understanding of the neurobiological aspects of the postpartum period.

PMID: 29774003 [PubMed]

Functional brain networks related to individual differences in human intelligence at rest.

Sat, 05/19/2018 - 14:40
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Functional brain networks related to individual differences in human intelligence at rest.

Sci Rep. 2016 08 26;6:32328

Authors: Hearne LJ, Mattingley JB, Cocchi L

Abstract
Intelligence is a fundamental ability that sets humans apart from other animal species. Despite its importance in defining human behaviour, the neural networks responsible for intelligence are not well understood. The dominant view from neuroimaging work suggests that intelligent performance on a range of tasks is underpinned by segregated interactions in a fronto-parietal network of brain regions. Here we asked whether fronto-parietal interactions associated with intelligence are ubiquitous, or emerge from more widespread associations in a task-free context. First we undertook an exploratory mapping of the existing literature on functional connectivity associated with intelligence. Next, to empirically test hypotheses derived from the exploratory mapping, we performed network analyses in a cohort of 317 unrelated participants from the Human Connectome Project. Our results revealed a novel contribution of across-network interactions between default-mode and fronto-parietal networks to individual differences in intelligence at rest. Specifically, we found that greater connectivity in the resting state was associated with higher intelligence scores. Our findings highlight the need to broaden the dominant fronto-parietal conceptualisation of intelligence to encompass more complex and context-specific network dynamics.

PMID: 27561736 [PubMed - indexed for MEDLINE]

Cross-modal plasticity among sensory networks in neuromyelitis optica spectrum disorders.

Fri, 05/18/2018 - 13:40
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Cross-modal plasticity among sensory networks in neuromyelitis optica spectrum disorders.

Mult Scler. 2018 May 01;:1352458518778008

Authors: Rocca MA, Savoldi F, Valsasina P, Radaelli M, Preziosa P, Comi G, Falini A, Filippi M

Abstract
OBJECTIVE: To explore resting-state (RS) functional connectivity (FC) of the main sensory/motor networks of patients with neuromyelitis optica spectrum disorders (NMOSDs), clinically isolated optic neuritis (ON), and myelitis.
METHODS: Clinical evaluation and RS fMRI were obtained from 28 NMOSD, 11 recurrent ON, and 12 recurrent myelitis patients and 30 healthy controls. Between-group RS FC comparisons and correlations with motor performance were assessed (SPM12) on the main sensory/motor RS networks (RSNs) identified by independent component analysis. Functional network connectivity analysis estimated inter-network connectivity.
RESULTS: Intra- and inter-network RS FCs were reduced in RSNs associated to somatosensory modalities affected by pathology: regions of the primary visual network in ON patients, of the sensorimotor networks in myelitis patients, and of the sensorimotor and secondary visual networks in NMOSD patients. The opposite trend was observed in regions of RSNs spared by pathology: the auditory and part of visual networks in NMOSD, the secondary visual and sensorimotor networks in ON, and the primary visual network in myelitis patients. Better motor performance correlated with higher RS FC of spared RSNs.
CONCLUSION: Sensory and motor RSN abnormalities occur in NMOSD. Loss of function within disease-target networks may elicit cross-modal plasticity across sensory networks potentially preserving clinical function.

PMID: 29771186 [PubMed - as supplied by publisher]

Accurate nonlinear mapping between MNI volumetric and FreeSurfer surface coordinate systems.

Fri, 05/18/2018 - 13:40
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Accurate nonlinear mapping between MNI volumetric and FreeSurfer surface coordinate systems.

Hum Brain Mapp. 2018 May 16;:

Authors: Wu J, Ngo GH, Greve D, Li J, He T, Fischl B, Eickhoff SB, Yeo BTT

Abstract
The results of most neuroimaging studies are reported in volumetric (e.g., MNI152) or surface (e.g., fsaverage) coordinate systems. Accurate mappings between volumetric and surface coordinate systems can facilitate many applications, such as projecting fMRI group analyses from MNI152/Colin27 to fsaverage for visualization or projecting resting-state fMRI parcellations from fsaverage to MNI152/Colin27 for volumetric analysis of new data. However, there has been surprisingly little research on this topic. Here, we evaluated three approaches for mapping data between MNI152/Colin27 and fsaverage coordinate systems by simulating the above applications: projection of group-average data from MNI152/Colin27 to fsaverage and projection of fsaverage parcellations to MNI152/Colin27. Two of the approaches are currently widely used. A third approach (registration fusion) was previously proposed, but not widely adopted. Two implementations of the registration fusion (RF) approach were considered, with one implementation utilizing the Advanced Normalization Tools (ANTs). We found that RF-ANTs performed the best for mapping between fsaverage and MNI152/Colin27, even for new subjects registered to MNI152/Colin27 using a different software tool (FSL FNIRT). This suggests that RF-ANTs would be useful even for researchers not using ANTs. Finally, it is worth emphasizing that the most optimal approach for mapping data to a coordinate system (e.g., fsaverage) is to register individual subjects directly to the coordinate system, rather than via another coordinate system. Only in scenarios where the optimal approach is not possible (e.g., mapping previously published results from MNI152 to fsaverage), should the approaches evaluated in this manuscript be considered. In these scenarios, we recommend RF-ANTs (https://github.com/ThomasYeoLab/CBIG/tree/master/stable_projects/registration/Wu2017_RegistrationFusion).

PMID: 29770530 [PubMed - as supplied by publisher]

Adolescent Condom Use and Connectivity in the Social-Planful Brain.

Fri, 05/18/2018 - 01:00

Adolescent Condom Use and Connectivity in the Social-Planful Brain.

J Pediatr Psychol. 2018 May 14;:

Authors: Caouette JD, Hudson KA, Bryan AD, Feldstein Ewing SW

Abstract
Objective: To reduce rates of sexually transmitted infections (STIs) and unwanted pregnancy among adolescents, it is critical to investigate brain connectivity that may underlie adolescents' sexual health decision-making in the context of intercourse. This study explored relationships between adolescent condom use frequency and the brain's resting-state functional connectivity, to identify differential patterns of social-affective processing among sexually active youth.
Methods: In this study, N = 143 sexually active adolescents (68.5% male, Mage = 16.2 years, SD = 1.06) completed magnetic resonance imaging and reported past 3-month frequency of condom use. Resting-state connectivity, seeded on a social region of the brain, the temporoparietal junction (TPJ), was assessed to determine its correspondence with protected sex (condom use).
Results: Condom use was associated with positive connectivity between the left TPJ and bilateral inferior frontal gyrus (IFG). This relationship was observed in adolescent males only; no connectivity differences were observed with adolescent females.
Conclusions: This study reflects functional synchrony between nodes of the "social brain," including the TPJ, and a region of planfulness and control, the IFG. The relationship between these regions suggests that adolescents who have more coordinated systems of communication between these critical components of the brain are more likely to be successful in planning and engaging in safer sexual decision-making; for young males, this differentiated more frequent from less frequent condom use. In turn, interventions designed to reduce STIs/human immunodeficiency virus may benefit from targeting social-planfulness dimensions to help youth implement safer sex behaviors.

PMID: 29767781 [PubMed - as supplied by publisher]

Amyloid causes intermittent network disruptions in cognitively intact older subjects.

Fri, 05/18/2018 - 01:00

Amyloid causes intermittent network disruptions in cognitively intact older subjects.

Brain Imaging Behav. 2018 May 16;:

Authors: Mueller SG

Abstract
Recent findings in AD models but also human patients suggest that amyloid can cause intermittent neuronal hyperactivity. The overall goal of this study was to use dynamic fMRI analysis combined with graph analysis to a) characterize the graph analytical signature of two types of intermittent hyperactivity (spike-like (spike) and hypersynchronus-like (synchron)) in simulated data and b) to attempt to identify one of these signatures in task-free fMRIs of cognitively intact subjects (CN) with or without increased brain amyloid. The toolbox simtb was used to generate 33 data sets with 2 short spike events, 33 with 2 synchron and 33 baseline data sets. A combination of sliding windows, hierarchical cluster analysis and graph analysis was used to characterize the spike and the synchron signature. Florbetapir-F18 PET and task-free 3 T fMRI was acquired in 49 CN (age = 70.7 ± 6.4). Processing the real data with the same approach as the simulated data identified phases whose graph analytical signature resembled that of the synchron signature in the simulated data. The duration of these phases was positively correlated with amyloid load (r = 0.42, p < 0.05) and negatively with memory performance (r = -0.43, p < 0.05). In conclusion, amyloid positivity is associated with intermittent hyperactivity that is caused by short phases of hypersynchronous activity. The negative association with memory performance suggests that these disturbances have the potential to interfere with cognitive processes and could lead to cognitive impairment if they become more frequent or more severe with increasing amyloid deposition.

PMID: 29767302 [PubMed - as supplied by publisher]

Associations Between Daily Mood States and Brain Gray Matter Volume, Resting-State Functional Connectivity and Task-Based Activity in Healthy Adults.

Fri, 05/18/2018 - 01:00
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Associations Between Daily Mood States and Brain Gray Matter Volume, Resting-State Functional Connectivity and Task-Based Activity in Healthy Adults.

Front Hum Neurosci. 2018;12:168

Authors: Ismaylova E, Di Sante J, Gouin JP, Pomares FB, Vitaro F, Tremblay RE, Booij L

Abstract
Numerous studies have shown differences in the functioning in the areas of the frontal-limbic circuitry between depressed patients and controls. However, current knowledge on frontal-limbic neural substrates of individual differences in mood states in everyday life in healthy individuals is scarce. The present study investigates anatomical, resting-state, and functional neural correlates of daily mood states in healthy individuals. We expected to observe associations between mood and the frontal-limbic circuitry and the default-mode network (DMN). A total of 42 healthy adults (19 men, 23 women; 34 ± 1.2 years) regularly followed for behavior and psychosocial functioning since age of 6, underwent a functional magnetic resonance imaging scan, and completed a daily diary of mood states and related cognitions for 5 consecutive days. Results showed that individuals with smaller left hippocampal gray matter volumes experienced more negative mood and rumination in their daily life. Greater resting-state functional connectivity (rsFC) within the DMN, namely between posterior cingulate cortex (PCC) and medial prefrontal cortex regions as well as between PCC and precuneus, was associated with both greater negative and positive mood states in daily life. These rsFC results could be indicative of the role of the DMN regional functioning in emotional arousal, irrespective of valence. Lastly, greater daily positive mood was associated with greater activation in response to negative emotional stimuli in the precentral gyri, previously linked to emotional interference on cognitive control. Altogether, present findings might reflect neural mechanisms underlying daily affect and cognition among healthy individuals.

PMID: 29765312 [PubMed]

Ultrasound-guided fine needle aspiration of retropharyngeal lymph nodes after radiotherapy for nasopharyngeal carcinoma: a novel technique for accurate diagnosis.

Fri, 05/18/2018 - 01:00
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Ultrasound-guided fine needle aspiration of retropharyngeal lymph nodes after radiotherapy for nasopharyngeal carcinoma: a novel technique for accurate diagnosis.

Cancer Commun (Lond). 2018 May 09;38(1):20

Authors: He LJ, Xie C, Li Y, Luo LN, Pan K, Gao XY, Liu LZ, Gao JM, Luo GY, Shan HB, Chen MY, Zhao C, Fan WJ, Yang P, Xu GL, Li JJ

Abstract
BACKGROUND: Enlarged retropharyngeal lymph nodes (RLNs) are very common in patients with nasopharyngeal carcinoma (NPC) undergoing radiotherapy. The most suitable treatment option for enlarged RLNs depends on the pathological results. However, RLN sampling is difficult and imminent in the clinic setting. We recently developed a novel minimally invasive technique termed endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) for sampling RLN tissues sufficient for pathological or cytological diagnosis.
METHODS: We enrolled 30 post-radiotherapy patients with NPC with suspected RLN metastasis detected via magnetic resonance imaging (MRI). The EUS probe was introduced into the nasopharynx via the nostrils, and EUS was then used to scan the retropharyngeal space and locate the RLN in the anterior carotid sheath. EUS-FNA was subsequently performed. The safety and efficacy of using EUS-FNA to sample the RLN tissues were assessed.
RESULTS: Strips of tissue were successfully sampled from all patients using EUS-FNA. Of the 30 patients, 23 were confirmed to have cancer cells in the biopsied tissues via pathology or cytology examinations with 1 EUS-FNA biopsy session. The seven cases without confirmed cancer cells were subsequently reanalyzed by using another EUS-FNA biopsy session, and two more cases were confirmed possessing cancer cells. The other five patients without confirmed cancer cells were closely followed with MRI every month for 3 months. After follow-up for 3 months, three patients were still considered cancer-free due to the presence of RLNs with stable or shrinking diameters. The rest two patients who showed progressive disease underwent a third EUS-FNA biopsy procedure and were further confirmed to be cancer cell-positive. In the whole cohort reported here, the EUS-FNA procedure was not associated with any severe complications.
CONCLUSION: EUS-FNA is a safe and effective diagnostic approach for sampling tissues from the RLNs in patients with suspected recurrent NPC.

PMID: 29764509 [PubMed - in process]

Functional connectivity of hippocampal subregions in PTSD: relations with symptoms.

Fri, 05/18/2018 - 01:00
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Functional connectivity of hippocampal subregions in PTSD: relations with symptoms.

BMC Psychiatry. 2018 May 15;18(1):129

Authors: Malivoire BL, Girard TA, Patel R, Monson CM

Abstract
BACKGROUND: Posttraumatic stress disorder (PTSD) is associated with abnormal hippocampal activity; however, the functional connectivity (FC) of the hippocampus with other brain regions in PTSD and its relations with symptoms warrants further attention. We investigated subregional hippocampal FC in PTSD during a resting state compared with a trauma-exposed control (TEC) group. Based on extant research, we targeted the FCs of the anterior and posterior hippocampal subregions with the amygdala, medial prefrontal cortex (mPFC), and the posterior cingulate (PCC).
METHODS: Resting-state functional magnetic resonance images were acquired from 11 individuals with PTSD and 13 trauma-exposed controls. Anterior and posterior hippocampal FC was compared between groups. Within the PTSD and TEC groups, subregional hippocampal FC was correlated with scores on the Clinician-Administered PTSD Scale (CAPS) at time of scan and 4 months post-scan.
RESULTS: Those with PTSD had significantly greater FC compared with the TEC group between the left posterior hippocampus and the bilateral PCC (g's > .96). Direct contrasts of the Fisher z-transformed coefficients indicated that the correlations between CAPS scores 4 months post scan and the FC between the left hippocampal head and the right PCC (z = - 2.07, p = .039) as well as the FC between the right hippocampal tail and the right mPFC (z = - 2.19, p = .029) were significantly greater in the PTSD group compared to the TEC group.
CONCLUSIONS: These results support between-group differences in posterior hippocampal FC and different relations with PTSD future symptoms, underscoring associations with the anterior and posterior hippocampus. These findings enrich our understanding of PTSD pathophysiology and provide support for future investigations of imaging biomarkers predictive of disease progression.

PMID: 29764396 [PubMed - in process]

Relationship between Duration of Untreated Psychosis and Intrinsic Corticostriatal Connectivity in Patients with Early Phase Schizophrenia.

Fri, 05/18/2018 - 01:00
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Relationship between Duration of Untreated Psychosis and Intrinsic Corticostriatal Connectivity in Patients with Early Phase Schizophrenia.

Neuropsychopharmacology. 2017 Oct;42(11):2214-2221

Authors: Sarpal DK, Robinson DG, Fales C, Lencz T, Argyelan M, Karlsgodt KH, Gallego JA, John M, Kane JM, Szeszko PR, Malhotra AK

Abstract
Patients with first-episode psychosis experience psychotic symptoms for a mean of up to 2 years prior to initiation of treatment, and long duration of untreated psychosis (DUP) is associated with poor clinical outcomes. Meanwhile, evidence compiled from numerous studies suggests that longer DUP is not associated with structural brain abnormalities. To date, few studies have examined the relationship between DUP and functional neuroimaging measures. In the present study, we used seed-based resting-state functional connectivity to examine the impact of DUP on corticostriatal circuitry. We included 83 patients with early phase schizophrenia and minimal exposure to antipsychotic drugs (<2 years), who underwent resting state scanning while entering 12 weeks of prospective treatment with second-generation antipsychotic drugs. Functional connectivity maps of the striatum were generated and examined in relation to DUP as a covariate. Mediation analyses were performed on a composite measure of corticostriatal connectivity derived from the significant results of our DUP analysis. We found that longer DUP correlated with worse response to treatment as well as overall decreased functional connectivity between striatal nodes and specific regions within frontal and parietal cortices. Moreover, the relationship between DUP and treatment response was significantly mediated by corticostriatal connectivity. Our results indicate that variation in corticostriatal circuitry may play a role in the relationship between longer DUP and worsened response to treatment. Future prospective studies are necessary to further characterize potential causal links between DUP, striatal circuitry and clinical outcomes.

PMID: 28294137 [PubMed - indexed for MEDLINE]

Modulation of functional activity and connectivity by acupuncture in patients with Alzheimer disease as measured by resting-state fMRI.

Wed, 05/16/2018 - 12:00
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Modulation of functional activity and connectivity by acupuncture in patients with Alzheimer disease as measured by resting-state fMRI.

PLoS One. 2018;13(5):e0196933

Authors: Zheng W, Su Z, Liu X, Zhang H, Han Y, Song H, Lu J, Li K, Wang Z

Abstract
Acupuncture has been used in the therapy of Alzheimer disease (AD); however, its neural mechanisms are still unclear. The aim of this study is to examine the effect of acupuncture on the functional connectivity in AD by using resting-state functional magnetic resonance imaging (rs-fMRI). Twenty-eight subjects (14 AD and 14 normal controls) participated in this study. The rs-fMRI data were acquired before and after acupuncture stimulation at the acupoints of Tai chong (Liv3) and Hegu (LI4). During the baseline resting state, by using the amplitude of low-frequency fluctuations (ALFF), we found a significantly decreased or increased ALFF in the AD patients relative to the controls. These regions were located in the right superior frontal gyrus (SFG), left postcentral gyrus, subgenual cingulate cortex (SCC), right middle cingulate cortex (MCC), right inferior frontal gyrus (IFG), right hippocampus and the right inferior temporal gyrus (ITG). Then, we selected these brain regions as seeds to investigate whether regional activity and functional connectivity could be modulated by acupuncture in the AD patients. When compared to the pre-acupuncture stage, several of the above regions showed an increased or decreased ALFF after acupuncture in the AD patients. In addition, the functional connectivity between the hippocampus and the precentral gyrus showed enhancement after acupuncture in the AD patients. Finally, there were close correlations between the functional activity, connectivity and clinical performance in the AD patients. The current study confirmed that acupuncture at Tai chong (Liv3) and He gu (LI4) can modulate functional activity and connectivity of specific cognition-related regions in AD patients.

PMID: 29763448 [PubMed - in process]

Functional magnetic resonance imaging in glioma patients: from clinical applications to future perspectives.

Wed, 05/16/2018 - 12:00
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Functional magnetic resonance imaging in glioma patients: from clinical applications to future perspectives.

Q J Nucl Med Mol Imaging. 2018 May 14;:

Authors: Volz LJ, Kocher M, Lohmann P, Shah NJ, Fink GR, Galldiks N

Abstract
Functional magnetic resonance imaging (fMRI) allows the non-invasive assessment of human brain activity in-vivo. In glioma patients, fMRI is frequently used to determine the individual functional anatomy of the motor and language network in a pre-surgical setting to optimize surgical procedures and prevent extensive damage to functionally eloquent areas. Novel developments based on resting- state fMRI may help to improve pre-surgical planning for patients which are unable to perform structured tasks and might extend pre-surgical mapping to include additional functional networks. Recent advances indicate a promising potential for future applications of fMRI in glioma patients which might help to identify neoplastic tissue or predict the long-term functional outcome of individual patients.

PMID: 29761998 [PubMed - as supplied by publisher]

[Degree centrality of the functional network in schizophrenia patients].

Wed, 05/16/2018 - 12:00
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[Degree centrality of the functional network in schizophrenia patients].

Sheng Wu Yi Xue Gong Cheng Xue Za Zhi. 2017 Dec 01;34(6):837-841

Authors: Duan M, Jiang Y, Chen X, Luo C, Yao D

Abstract
The aim of the present study was to investigate the alternations of brain functional networks at resting state in the schizophrenia (SCH) patients using voxel-wise degree centrality (DC) method. The resting-state functional magnetic resonance imaging (rfMRI) data were collected from 41 SCH patients and 41 matched healthy control subjects and then analyzed by voxel-wise DC method. The DC maps between the patient group and the control group were compared using by two sample t test. The correlation analysis was also performed between DC values and clinical symptom and illness duration in SCH group. Results showed that compared with the control group, SCH patients exhibited significantly decreased DC value in primary sensorimotor network, and increased DC value in executive control network. In addition, DC value of the regions with obvious differences between the two groups significantly correlated to Positive and Negative Syndrome Scale (PANSS) scores and illness duration of SCH patients. The study showed the abnormal functional integration in primary sensorimotor network and executive control network in SCH patients.

PMID: 29761976 [PubMed]

[Automatic classification of first-episode, drug-naive schizophrenia with multi-modal magnetic resonance imaging].

Wed, 05/16/2018 - 12:00
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[Automatic classification of first-episode, drug-naive schizophrenia with multi-modal magnetic resonance imaging].

Sheng Wu Yi Xue Gong Cheng Xue Za Zhi. 2017 Oct 01;34(5):674-680

Authors: Yang Y, Zhang Y, Wu F, Lu X, Ning Y, Huang B, Du X, Li C, Wang K, Wu X, Wu K

Abstract
A great number of studies have demonstrated the structural and functional abnormalities in chronic schizophrenia (SZ) patients. However, few studies analyzed the differences between first-episode, drug-naive SZ (FESZ) patients and normal controls (NCs). In this study, we recruited 44 FESZ patients and 56 NCs, and acquired their multi-modal magnetic resonance imaging (MRI) data, including structural and resting-state functional MRI data. We calculated gray matter volume (GMV), regional homogeneity (ReHo), amplitude of low frequency fluctuation (ALFF), and degree centrality (DC) of 90 brain regions, basing on an automated anatomical labeling (AAL) atlas. We then applied these features into support vector machine (SVM) combined with recursive feature elimination (RFE) to discriminate FESZ patients from NCs. Our results showed that the classifier using the combination of ReHo and ALFF as input features achieved the best performance (an accuracy of 96.97%). Moreover, the most discriminative features for classification were predominantly located in the frontal lobe. Our findings may provide potential information for understanding the neuropathological mechanism of SZ and facilitate the development of biomarkers for computer-aided diagnosis of SZ patients.

PMID: 29761952 [PubMed]

Fluctuations of the EEG-fMRI correlation reflect intrinsic strength of functional connectivity in default mode network.

Wed, 05/16/2018 - 12:00
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Fluctuations of the EEG-fMRI correlation reflect intrinsic strength of functional connectivity in default mode network.

J Neurosci Res. 2018 May 14;:

Authors: Keinänen T, Rytky S, Korhonen V, Huotari N, Nikkinen J, Tervonen O, Palva JM, Kiviniemi V

Abstract
Both functional magnetic resonance imaging (fMRI) and electrophysiological recordings have revealed that resting-state functional connectivity is temporally variable in human brain. Combined full-band electroencephalography-fMRI (fbEEG-fMRI) studies have shown that infraslow (<.1 Hz) fluctuations in EEG scalp potential are correlated with the blood-oxygen-level-dependent (BOLD) fMRI signals and that also this correlation appears variable over time. Here, we used simultaneous fbEEG-fMRI to test the hypothesis that correlation dynamics between BOLD and fbEEG signals could be explained by fluctuations in the activation properties of resting-state networks (RSNs) such as the extent or strength of their activation. We used ultrafast magnetic resonance encephalography (MREG) fMRI to enable temporally accurate and statistically robust short-time-window comparisons of infra-slow fbEEG and BOLD signals. We found that the temporal fluctuations in the fbEEG-BOLD correlation were dependent on RSN connectivity strength, but not on the mean signal level or magnitude of RSN activation or motion during scanning. Moreover, the EEG-fMRI correlations were strongest when the intrinsic RSN connectivity was strong and close to the pial surface. Conversely, weak fbEEG-BOLD correlations were attributable to periods of less coherent or spatially more scattered intrinsic RSN connectivity, or RSN activation in deeper cerebral structures. The results thus show that the on-average low correlations between infra-slow EEG and BOLD signals are, in fact, governed by the momentary coherence and depth of the underlying RSN activation, and may reach systematically high values with appropriate source activities. These findings further consolidate the notion of slow scalp potentials being directly coupled to hemodynamic fluctuations.

PMID: 29761531 [PubMed - as supplied by publisher]

The effects of cognitive behavioral therapy on resting-state functional brain network in drug-naive patients with obsessive-compulsive disorder.

Wed, 05/16/2018 - 12:00
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The effects of cognitive behavioral therapy on resting-state functional brain network in drug-naive patients with obsessive-compulsive disorder.

Brain Behav. 2018 May;8(5):e00963

Authors: Li P, Yang X, Greenshaw AJ, Li S, Luo J, Han H, Liu J, Zhong Z, Guo Z, Xiong H, Yao S, Chen Y, Sun J, Li Z

Abstract
Objectives: Although cognitive behavioral therapy (CBT) is an effective treatment for obsessive-compulsive disorder (OCD), the treatment mechanisms remain poorly understood. This study aimed to investigate the effects of CBT on changes in the intrinsic whole-brain functional network of OCD patients.
Materials and Methods: Twenty drug-naive and noncomorbid OCD patients were recruited, and resting-state functional magnetic resonance imaging was performed before and after 12 weeks of CBT. Moreover, 20 healthy controls were scanned twice with a 12-week interval. A graph-theory degree centrality (DC) approach and functional connectivity method were used to analyze the whole-brain functional network hub and connectivity changes in OCD patients before and after CBT treatment.
Results: A significant group × time interaction on DC was found in the left dorsolateral prefrontal cortex (DLPFC); the DC in the left DLPFC was significantly reduced after CBT treatment. Resting-state functional connectivity (RSFC) between the left DLPFC and right orbitofrontal cortex was increased in the OCD patients at baseline, and normalized after CBT treatment. RSFC changes between the left DLPFC and default mode network (DMN) positively correlated with changes in clinical symptoms in OCD patients.
Conclusions: These findings suggest that CBT can modulate changes in intrinsic functional network hubs in the cortico-striato-thalamo-cortical circuit in OCD patients. Cognitive control network and DMN connectivity may be a potential imaging biomarker for evaluating CBT treatment for OCD.

PMID: 29761016 [PubMed - in process]

The asymmetry of neural symptoms in Wilson's disease patients detecting by diffusion tensor imaging, resting-state functional MRI, and susceptibility-weighted imaging.

Wed, 05/16/2018 - 12:00
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The asymmetry of neural symptoms in Wilson's disease patients detecting by diffusion tensor imaging, resting-state functional MRI, and susceptibility-weighted imaging.

Brain Behav. 2018 May;8(5):e00930

Authors: Zhou XX, Li XH, Chen DB, Wu C, Feng L, Chu JP, Yang ZY, Li XB, Qin H, Li GD, Huang HW, Liang YY, Liang XL

Abstract
Objective: To investigate the cause of the motor asymmetry in Wilson's disease (WD) patients using functional MRI.
Methods: Fifty patients with WD and 20 age-matched healthy controls were enrolled. Neurological symptoms were scored using the modified Young Scale. All study subjects underwent diffusion tensor imaging (DTI), susceptibility-weighted imaging (SWI), and resting-state functional MRI (rs-fMRI) of the brain. Six regions of interest (ROI) were chosen. Fiber volumes between ROIs on DTI, corrected phase (CP) values on SWI, amplitude of low-frequency fluctuation (ALFF), and regional homogeneity (REHO) values on rs-fMRI were determined. Asymmetry index (right or left value/left or right value) was evaluated.
Results: Asymmetry of rigidity, tremor, choreic movement, and gait abnormality (asymmetry index = 1.33, 1.39, 1.36, 1.40), fiber tracts between the GP and substantia nigra (SN), GP and PU, SN and thalamus (TH), SN and cerebellum, head of the caudate nucleus (CA) and SN, PU and CA, CA and TH, TH and cerebellum (asymmetry index = 1.233, 1.260, 1.269, 1.437, 1.503, 1.138, 1.145, 1.279), CP values in the TH, SN (asymmetry index = 1.327, 1.166), ALFF values, and REHO values of the TH (asymmetry index = 1.192, 1.233) were found. Positive correlation between asymmetry index of rigidity and fiber volumes between the GP and SN, SN and TH (r = .221, .133, p = .043, .036), and tremor and fiber volumes between the CA and TH (r = .045, p = .040) was found.
Conclusions: The neurological symptoms of patients with WD were asymmetry. The asymmetry of fiber projections may be the main cause of motor asymmetry in patients with WD.

PMID: 29761003 [PubMed - in process]

Testing assumptions on prefrontal transcranial direct current stimulation: Comparison of electrode montages using multimodal fMRI.

Wed, 05/16/2018 - 12:00
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Testing assumptions on prefrontal transcranial direct current stimulation: Comparison of electrode montages using multimodal fMRI.

Brain Stimul. 2018 May 04;:

Authors: Wörsching J, Padberg F, Goerigk S, Heinz I, Bauer C, Plewnia C, Hasan A, Ertl-Wagner B, Keeser D

Abstract
BACKGROUND: Transcranial direct current stimulation (tDCS) of the prefrontal cortex (PFC) has been widely applied in cognitive neurosciences and advocated as a therapeutic intervention, e.g. in major depressive disorder. Although several targets and protocols have been suggested, comparative studies of tDCS parameters, particularly electrode montages and their cortical targets, are still lacking.
OBJECTIVE: This study investigated a priori hypotheses on specific effects of prefrontal-tDCS montages by using multimodal functional magnetic resonance imaging (fMRI) in healthy participants.
METHODS: 28 healthy male participants underwent three common active-tDCS montages and sham tDCS in a pseudo-randomized order, comprising a total of 112 tDCS-fMRI sessions. Active tDCS was applied at 2 mA for 20 min. Before and after tDCS, a resting-state fMRI (RS fMRI) was recorded, followed by a task fMRI with a delayed-response working-memory (DWM) task for assessing cognitive control over emotionally negative or neutral distractors.
RESULTS: After tDCS with a cathode-F3/anode-F4 montage, RS-fMRI connectivity decreased in a medial part of the left PFC. Also, after the same stimulation condition, regional brain activity during DWM retrieval decreased more in this area after negative than after neutral distraction, and responses to the DWM task were faster, independent of distractor type.
CONCLUSION: The current study does not confirm our a priori hypotheses on direction and localization of polarity-dependent tDCS effects using common bipolar electrode montages over PFC regions, but it provides evidence for montage-specific effects on multimodal neurophysiological and behavioral outcome measures. Systematic research on the actual targets and the respective dose-response relationships of prefrontal tDCS is warranted.

PMID: 29759944 [PubMed - as supplied by publisher]

Structural and functional connectivity underlying grey matter covariance: impact of developmental insult.

Wed, 05/16/2018 - 12:00
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Structural and functional connectivity underlying grey matter covariance: impact of developmental insult.

Brain Connect. 2018 May 15;:

Authors: Paquola C, Bennett M, Lagopoulos J

Abstract
Structural covariance networks (SCNs) may offer unique insights into the developmental impact of childhood maltreatment because they are thought to reflect coordinated maturation of distinct grey matter regions. T1-weighted magnetic resonance images were acquired from 121 young people with emerging mental illness. Diffusion weighted and resting state functional imaging was also acquired from a random subset of the participants (n=62). Ten study-specific SCNs were identified using a whole brain grey matter independent component analysis. The effects of childhood maltreatment and age on average grey matter density and the expression of each SCN were calculated. Childhood maltreatment was linked to age-related decreases in grey matter density across a SCN that overlapped with the default mode and fronto-parietal networks. Resting state functional connectivity and structural connectivity were calculated in the study-specific SCN and across the whole brain. Grey matter covariance was significantly correlated with rsFC across the SCN, and rsFC fully mediated the relationship between grey matter covariance and structural connectivity in the non-maltreated group. A unique association of grey matter covariance with structural connectivity was detected amongst individuals with a history of childhood maltreatment. Perturbation of grey matter development across the default mode and fronto-parietal networks following childhood maltreatment may have significant implications for mental well-being, given the networks' roles in self-referential activity. Cross-modal comparisons suggest reduced grey matter following childhood maltreatment could arise from deficient functional activity earlier in life.

PMID: 29758994 [PubMed - as supplied by publisher]

Forebrain knock-out of torsinA reduces striatal free-water and impairs whole-brain functional connectivity in a symptomatic mouse model of DYT1 dystonia.

Wed, 05/16/2018 - 12:00
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Forebrain knock-out of torsinA reduces striatal free-water and impairs whole-brain functional connectivity in a symptomatic mouse model of DYT1 dystonia.

Neurobiol Dis. 2017 Oct;106:124-132

Authors: DeSimone JC, Pappas SS, Febo M, Burciu RG, Shukla P, Colon-Perez LM, Dauer WT, Vaillancourt DE

Abstract
Multiple lines of evidence implicate striatal dysfunction in the pathogenesis of dystonia, including in DYT1, a common inherited form of the disease. The impact of striatal dysfunction on connected motor circuits and their interaction with other brain regions is poorly understood. Conditional knock-out (cKO) of the DYT1 protein torsinA from forebrain cholinergic and GABAergic neurons creates a symptomatic model that recapitulates many characteristics of DYT1 dystonia, including the developmental onset of overt twisting movements that are responsive to antimuscarinic drugs. We performed diffusion MRI and resting-state functional MRI on cKO mice of either sex to define abnormalities of diffusivity and functional connectivity in cortical, subcortical, and cerebellar networks. The striatum was the only region to exhibit an abnormality of diffusivity, indicating a selective microstructural deficit in cKO mice. The striatum of cKO mice exhibited widespread increases in functional connectivity with somatosensory cortex, thalamus, vermis, cerebellar cortex and nuclei, and brainstem. The current study provides the first in vivo support that direct pathological insult to forebrain torsinA in a symptomatic mouse model of DYT1 dystonia can engage genetically normal hindbrain regions into an aberrant connectivity network. These findings have important implications for the assignment of a causative region in CNS disease.

PMID: 28673740 [PubMed - indexed for MEDLINE]

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