New resting-state fMRI related studies at PubMed

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Behavioral deficits in left hemispatial neglect are related to a reduction of spontaneous neuronal activity in the right superior parietal lobule.

Fri, 01/24/2020 - 14:20
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Behavioral deficits in left hemispatial neglect are related to a reduction of spontaneous neuronal activity in the right superior parietal lobule.

Neuropsychologia. 2020 Jan 20;:107356

Authors: Machner B, von der Gablentz J, Göttlich M, Heide W, Helmchen C, Sprenger A, Münte TF

Abstract
Focal brain lesions may induce dysfunctions in distant brain regions leading to behavioral impairments. Based on this concept of 'diaschisis', spatial neglect following stroke has been related to structural damage of the right-lateralized ventral attention network (VAN) and disrupted inter-hemispheric functional connectivity (FC) in the bilateral dorsal attention network (DAN). We questioned whether neglect-related behavioral deficits may be determined by local dysfunction of a specific region within these brain networks. We investigated acute right-hemisphere stroke patients with left hemispatial neglect using resting-state functional MRI, neuropsychological tests of spatial attention and clinical assessment of neglect-related functional disability. In addition to conventional FC analyses between different cortical regions of interest (ROIs) in the DAN/VAN, we extracted the fractional amplitude of low frequency fluctuations (fALFF) from each ROI as a marker of regional spontaneous neuronal activity. Although DAN regions (as opposed to the VAN regions) were largely spared from structural brain damage, they exhibited a significant reduction of inter-hemispheric FC. However, significant fMRI-behavior correlations were revealed specifically for the fALFF of one DAN-ROI in the right superior parietal lobule (SPL): the smaller the fALFF in the right posterior intraparietal sulcus, the more severe the patient's pathological attention bias and neglect-related functional impairment. In line with 'diaschisis', our findings confirm a crucial role of the non-lesioned but dysfunctional right SPL for the emergence of spatial neglect and its behavioral consequences. They further support targeting the SPL dysfunction by non-invasive brain stimulation in neglect rehabilitation.

PMID: 31972231 [PubMed - as supplied by publisher]

Antidepressants normalize brain flexibility associated with multi-dimensional symptoms in major depressive patients.

Fri, 01/24/2020 - 14:20
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Antidepressants normalize brain flexibility associated with multi-dimensional symptoms in major depressive patients.

Prog Neuropsychopharmacol Biol Psychiatry. 2020 Jan 20;:109866

Authors: Tian S, Zhang S, Mo Z, Chattun MR, Wang Q, Wang L, Zhu R, Shao J, Wang X, Yao Z, Si T, Lu Q

Abstract
BACKGROUND: The fundamental pathophysiology of major depressive disorder (MDD) could be characterized by functional brain networks which tightly and dynamically connect into groups as communities, making the flexible brain possible to external multifarious demands. We aim to scrutinize what brain dynamics go awry in MDD and antidepressants effects on multi-dimensional symptoms.
METHODS: Thirty-five patients and thirty-five controls underwent resting-state functional magnetic resonance imaging (MRI). Patients were scanned before and after 8 or 12 weeks of pharmacotherapy. Group independent component analysis decomposed resting-state images to instinct networks and networks' integrated flexibility was calculated. Network flexibility between patients at baseline and after therapy were compared.
RESULTS: All patients completed the clinical trial and MRI scans. Following antidepressants treatment, we found significant normalization of reduced network flexibility in default mode network (DMN) and cognitive control network (CCN) of MDD patients. Selectively significant correlations between network flexibility and multi-dimensional symptoms such as anxiety/somatization and hysteresis factor were also found.
CONCLUSIONS: "Hypoflexible" CCN may involve in anxiety syndrome. Low flexibility in DMN may be indicative of hysteresis. These suggest an important pathophysiology of depressive manifestation of MDD. The antidepressant-induced normalization of the "hypoflexibility" suggests a selective pathway through which antidepressants may alleviate symptoms in depression.

PMID: 31972187 [PubMed - as supplied by publisher]

Modulation of Distinct Intrinsic Resting State Brain Networks by Acute Exercise Bouts of Differing Intensity.

Fri, 01/24/2020 - 14:20
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Modulation of Distinct Intrinsic Resting State Brain Networks by Acute Exercise Bouts of Differing Intensity.

Brain Plast. 2019 Dec 26;5(1):39-55

Authors: Schmitt A, Upadhyay N, Martin JA, Rojas S, Strüder HK, Boecker H

Abstract
Acute exercise bouts alter resting state functional connectivity (rs-FC) within cognitive, sensorimotor, and affective networks, but it remains unknown how these effects are influenced by exercise intensity. Twenty-five male athletes underwent individual fitness assessments using an incremental treadmill test. On separate days, they performed 'low' (35% below lactate threshold) and 'high' (20% above lactate threshold) intensity exercise bouts of 30 min. Rs-fMRI and Positive and Negative Affect Scale (PANAS) were acquired before and after each exercise bout. Networks of interest were extracted from twenty-two participants (3 dropouts). Pre-to-post changes and between conditions effects were evaluated using FSL's randomise by applying repeated measures ANOVA. Results were reported at p < 0.05, corrected for multiple comparisons using threshold free cluster enhancement. PANAS revealed a significant increase in positive mood after both exercise conditions. Significant effects were observed between conditions in the right affective and reward network (ARN), the right fronto parietal network (FPN) and the sensorimotor network (SMN). Pre-to-post comparisons after 'low' exercise intensity revealed a significant increase in rs-FC in the left and right FPN, while after 'high'-intensity exercise rs-FC decreased in the SMN and the dorsal attention network (DAN) and increased in the left ARN. Supporting recent findings, this study is the first to report distinct rs-FC alterations driven by exercise intensity: (i) Increased rs-FC in FPN may indicate beneficial functional plasticity for cognitive/attentional processing, (ii) increased rs-FC in ARN may be linked to endogenous opioid-mediated internal affective states. Finally, (iii) decreased rs-FC in the SMN may signify persistent motor fatigue. The distinct effects on rs-FC fit with theories of transient persistent network alterations after acute exercise bouts that are mediated by different exercise intensities and impact differentially on cognitive/attentional or affective responses.

PMID: 31970059 [PubMed]

Current Challenges in Translational and Clinical fMRI and Future Directions.

Fri, 01/24/2020 - 14:20
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Current Challenges in Translational and Clinical fMRI and Future Directions.

Front Psychiatry. 2019;10:924

Authors: Specht K

Abstract
Translational neuroscience is an important field that brings together clinical praxis with neuroscience methods. In this review article, the focus will be on functional neuroimaging (fMRI) and its applicability in clinical fMRI studies. In the light of the "replication crisis," three aspects will be critically discussed: First, the fMRI signal itself, second, current fMRI praxis, and, third, the next generation of analysis strategies. Current attempts such as resting-state fMRI, meta-analyses, and machine learning will be discussed with their advantages and potential pitfalls and disadvantages. One major concern is that the fMRI signal shows substantial within- and between-subject variability, which affects the reliability of both task-related, but in particularly resting-state fMRI studies. Furthermore, the lack of standardized acquisition and analysis methods hinders the further development of clinical relevant approaches. However, meta-analyses and machine-learning approaches may help to overcome current shortcomings in the methods by identifying new, and yet hidden relationships, and may help to build new models on disorder mechanisms. Furthermore, better control of parameters that may have an influence on the fMRI signal and that can easily be controlled for, like blood pressure, heart rate, diet, time of day, might improve reliability substantially.

PMID: 31969840 [PubMed]

Patterns of functional connectivity in an aging population: The Rotterdam Study.

Fri, 01/24/2020 - 14:20
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Patterns of functional connectivity in an aging population: The Rotterdam Study.

Neuroimage. 2019 04 01;189:432-444

Authors: Zonneveld HI, Pruim RH, Bos D, Vrooman HA, Muetzel RL, Hofman A, Rombouts SA, van der Lugt A, Niessen WJ, Ikram MA, Vernooij MW

Abstract
Structural brain markers are studied extensively in the field of neurodegeneration, but are thought to occur rather late in the process. Functional measures such as functional connectivity are gaining interest as potentially more subtle markers of neurodegeneration. However, brain structure and function are also affected by 'normal' brain ageing. More information is needed on how functional connectivity relates to aging, particularly in the absence of overt neurodegenerative disease. We investigated the association of age with resting-state functional connectivity in 2878 non-demented persons between 50 and 95 years of age (54.1% women) from the population-based Rotterdam Study. We obtained nine well-known resting state networks using data-driven methodology. Within the anterior default mode network, ventral attention network, and sensorimotor network, functional connectivity was significantly lower with older age. In contrast, functional connectivity was higher with older age within the visual network. Between resting state networks, we found patterns of both increases and decreases in connectivity in approximate equal proportions. Our results reinforce the notion that the aging brain undergoes a reorganization process, and serves as a solid basis for exploring functional connectivity as a preclinical marker of neurodegenerative disease.

PMID: 30659958 [PubMed - indexed for MEDLINE]

Continuous reorganization of cortical information flow in multiple sclerosis: A longitudinal fMRI effective connectivity study.

Thu, 01/23/2020 - 13:00
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Continuous reorganization of cortical information flow in multiple sclerosis: A longitudinal fMRI effective connectivity study.

Sci Rep. 2020 Jan 21;10(1):806

Authors: Fleischer V, Muthuraman M, Anwar AR, Gonzalez-Escamilla G, Radetz A, Gracien RM, Bittner S, Luessi F, Meuth SG, Zipp F, Groppa S

Abstract
Effective connectivity (EC) is able to explore causal effects between brain areas and can depict mechanisms that underlie repair and adaptation in chronic brain diseases. Thus, the application of EC techniques in multiple sclerosis (MS) has the potential to determine directionality of neuronal interactions and may provide an imaging biomarker for disease progression. Here, serial longitudinal structural and resting-state fMRI was performed at 12-week intervals over one year in twelve MS patients. Twelve healthy subjects served as controls (HC). Two approaches for EC quantification were used: Causal Bayesian Network (CBN) and Time-resolved Partial Directed Coherence (TPDC). The EC strength was correlated with the Expanded Disability Status Scale (EDSS) and Fatigue Scale for Motor and Cognitive functions (FSMC). Our findings demonstrated a longitudinal increase in EC between specific brain regions, detected in both the CBN and TPDC analysis in MS patients. In particular, EC from the deep grey matter, frontal, prefrontal and temporal regions showed a continuous increase over the study period. No longitudinal changes in EC were attested in HC during the study. Furthermore, we observed an association between clinical performance and EC strength. In particular, the EC increase in fronto-cerebellar connections showed an inverse correlation with the EDSS and FSMC. Our data depict continuous functional reorganization between specific brain regions indicated by increasing EC over time in MS, which is not detectable in HC. In particular, fronto-cerebellar connections, which were closely related to clinical performance, may provide a marker of brain plasticity and functional reserve in MS.

PMID: 31964982 [PubMed - in process]

An fMRI-based neural marker for migraine without aura.

Thu, 01/23/2020 - 13:00
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An fMRI-based neural marker for migraine without aura.

Neurology. 2020 Jan 21;:

Authors: Tu Y, Zeng F, Lan L, Li Z, Maleki N, Liu B, Chen J, Wang C, Park J, Lang C, Yujie G, Liu M, Fu Z, Zhang Z, Liang F, Kong J

Abstract
OBJECTIVE: To identify and validate an fMRI-based neural marker for migraine without aura (MwoA) and to examine its association with treatment response.
METHODS: We conducted cross-sectional studies with resting-state fMRI data from 230 participants and machine learning analyses. In studies 1 through 3, we identified, cross-validated, independently validated, and cross-sectionally validated an fMRI-based neural marker for MwoA. In study 4, we assessed the relationship between the neural marker and treatment responses in migraineurs who received a 4-week real or sham acupuncture treatment, or were waitlisted, in a registered clinical trial.
RESULTS: In study 1 (n = 116), we identified a neural marker with abnormal functional connectivity within the visual, default mode, sensorimotor, and frontal-parietal networks that could discriminate migraineurs from healthy controls (HCs) with 93% sensitivity and 89% specificity. In study 2 (n = 38), we investigated the generalizability of the marker by applying it to an independent cohort of migraineurs and HCs and achieved 84% sensitivity and specificity. In study 3 (n = 76), we verified the specificity of the marker with new datasets of migraineurs and patients with other chronic pain disorders (chronic low back pain and fibromyalgia) and demonstrated 78% sensitivity and 76% specificity for discriminating migraineurs from nonmigraineurs. In study 4 (n = 116), we found that the changes in the marker responses showed significant correlation with the changes in headache frequency in response to real acupuncture.
CONCLUSION: We identified an fMRI-based neural marker that captures distinct characteristics of MwoA and can link disease pattern changes to brain changes.

PMID: 31964691 [PubMed - as supplied by publisher]

Human brain functional network organization is disrupted following whole-brain radiation therapy.

Thu, 01/23/2020 - 13:00
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Human brain functional network organization is disrupted following whole-brain radiation therapy.

Brain Connect. 2020 Jan 22;:

Authors: Mitchell T, Seitzman B, Ballard N, Petersen SE, Shimony J, Leuthardt E

Abstract
Radiation therapy plays a vital role in the treatment of brain cancers, but frequently results in cognitive decline in the patients who receive it. Because the underlying mechanisms for this decline remains poorly understood, the brain is typically treated as a single, uniform volume when evaluating the toxic effects of radiation therapy plans. This ignorance represents a significant deficit in the field of radiation oncology, as the technology exists to manipulate dose distributions to spare regions of the brain, but there exists no body of knowledge regarding what is critical to spare. This deficit exists due to the numerous confounding factors that are frequently associated with radiotherapy, including the tumors themselves, other treatments such as surgery and chemotherapy, and dose gradients across the brain. Here, we present a case in which a 57 year-old male patient received a uniform dose of radiation across the whole brain, did not receive concurrent chemotherapy, had minimal surgical intervention and a small tumor burden, and received resting-state functional MRI scans before and after radiation therapy. To our knowledge, this is the first study on the effects of whole brain radiotherapy on functional network organization, and this patient's treatment regimen represents a rare and non-replicable opportunity to isolate the effects of radiation on functional connectivity. We observed substantial changes in the subject's behavior and functional network organization over a 12-month timeframe. Interestingly, the homogenous radiation dose to the brain had a heterogeneous effect on cortical networks, and the functional networks most affected correspond with observed cognitive behavioral deficits. This novel study suggests that the cognitive decline that occurs after whole-brain radiation therapy may be network specific and related to the disruption of large-scale distributed functional systems, and indicates that functional MRI is a promising avenue of study for optimizing cognitive outcomes following radiation therapy.

PMID: 31964163 [PubMed - as supplied by publisher]

Comparing directed functional connectivity between groups with confirmatory subgrouping GIMME.

Thu, 01/23/2020 - 13:00
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Comparing directed functional connectivity between groups with confirmatory subgrouping GIMME.

Neuroimage. 2019 03;188:642-653

Authors: Henry TR, Feczko E, Cordova M, Earl E, Williams S, Nigg JT, Fair DA, Gates KM

Abstract
Connectivity modeling in functional neuroimaging has become widely used method of analysis for understanding functional architecture. One method for deriving directed connectivity models is Group Iterative Multiple Model Estimation (GIMME; Gates and Molenaar, 2012). GIMME looks for commonalities across the sample to detect signal from noise and arrive at edges that exist across the majority in the group ("group-level edges") and individual-level edges. In this way, GIMME obtains generalizable results via the group-level edges while also allowing for between subject heterogeneity in connectivity, moving the field closer to obtaining reliable personalized connectivity maps. In this article, we present a novel extension of GIMME, confirmatory subgrouping GIMME, which estimates subgroup-level edges for a priori known groups (e.g. typically developing controls vs. clinical group). Detecting edges that consistently exist for individuals within predefined subgroups aids in interpretation of the heterogeneity in connectivity maps and allows for subgroup-specific inferences. We describe this algorithm, as well as several methods to examine the results. We present an empirical example that finds similarities and differences in resting state functional connectivity among four groups of children: typically developing controls (TDC), children with autism spectrum disorder (ASD), children with Inattentive (ADHD-I) and Combined (ADHD-C) Type ADHD. Findings from this study suggest common involvement of the left Broca's area in all the clinical groups, as well as several unique patterns of functional connectivity specific to a given disorder. Overall, the current approach and proof of principle findings highlight a novel and reliable tool for capturing heterogeneity in complex mental health disorders.

PMID: 30583065 [PubMed - indexed for MEDLINE]

Finding the baby in the bath water - evidence for task-specific changes in resting state functional connectivity evoked by training.

Thu, 01/23/2020 - 13:00
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Finding the baby in the bath water - evidence for task-specific changes in resting state functional connectivity evoked by training.

Neuroimage. 2019 03;188:524-538

Authors: Steel A, Thomas C, Trefler A, Chen G, Baker CI

Abstract
Resting-state functional connectivity (rsFC) between brain regions has been used for studying training-related changes in brain function during the offline period of skill learning. However, it is difficult to infer whether the observed training-related changes in rsFC measured between two scans occur as a consequence of task performance, whether they are specific to a given task, or whether they reflect confounding factors such as diurnal fluctuations in brain physiology that impact the MRI signal. Here, we sought to elucidate whether task-specific changes in rsFC are dissociable from time-of-day related changes by evaluating rsFC changes after participants were provided training in either a visuospatial task or a motor sequence task compared to a non-training condition. Given the nature of the tasks, we focused on changes in rsFC of the hippocampal and sensorimotor cortices after short-term training, while controlling for the effect of time-of-day. We also related the change in rsFC of task-relevant brain regions to performance improvement in each task. Our results demonstrate that, even in the absence of any experimental manipulation, significant changes in rsFC can be detected between two resting state functional MRI scans performed just a few hours apart, suggesting time-of-day has a significant impact on rsFC. However, by estimating the magnitude of the time-of-day effect, our findings also suggest that task-specific changes in rsFC can be dissociated from the changes attributed to time-of-day. Taken together, our results show that rsFC can provide insights about training-related changes in brain function during the offline period of skill learning. However, demonstrating the specificity of the changes in rsFC to a given task requires a rigorous experimental design that includes multiple active and passive control conditions, and robust behavioral measures.

PMID: 30578926 [PubMed - indexed for MEDLINE]

Brain and behavioral correlates of insulin resistance in youth with depression and obesity.

Thu, 01/23/2020 - 13:00
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Brain and behavioral correlates of insulin resistance in youth with depression and obesity.

Horm Behav. 2019 02;108:73-83

Authors: Singh MK, Leslie SM, Packer MM, Zaiko YV, Phillips OR, Weisman EF, Wall DM, Jo B, Rasgon N

Abstract
Depression, together with insulin resistance, is increasingly prevalent among youth. These conditions have traditionally been compartmentalized, but recent evidence suggests that a shared brain motivational network underlies their co-occurrence. We posit that, in the context of depressive symptoms, insulin resistance is associated with aberrant structure and functional connectivity in the Anterior Cingulate Cortex (ACC) and hippocampus. This motivational neural circuit underlies dysfunctional behavioral responses and increased sensitivity to rewarding aspects of ingesting high calorie food that lead to disinhibition of eating even when satiated. To investigate this shared mechanism, we evaluated a sample of forty-two depressed and overweight (BMI > 85th%) youth aged 9 to 17. Using ACC and hippocampus structural and seed-based regions of interest, we investigated associations between insulin resistance, depression, structure (ACC thickness, and ACC and hippocampal area), and resting-state functional connectivity (RSFC). We predicted that aberrant associations among these neural and behavioral characteristics would be stronger in insulin resistant compared to insulin sensitive youth. We found that youth with greater insulin resistance had higher levels of anhedonia and more food seeking behaviors, reduced hippocampal and ACC volumes, and greater levels of ACC and hippocampal dysconnectivity to fronto-limbic reward networks at rest. For youth with high levels of insulin resistance, thinner ACC and smaller hippocampal volumes were associated with more severe depressive symptoms, whereas the opposite was true for youth with low levels of insulin resistance. The ACC-hippocampal motivational network that subserves depression and insulin resistance separately, may represent a critical neural interaction that link these syndromes together.

PMID: 29596854 [PubMed - indexed for MEDLINE]

Characterizing intrinsic functional connectivity in relation to impaired self-regulation in intellectually able male youth with autism spectrum disorder.

Wed, 01/22/2020 - 12:00
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Characterizing intrinsic functional connectivity in relation to impaired self-regulation in intellectually able male youth with autism spectrum disorder.

Autism. 2020 Jan 21;:1362361319888104

Authors: Lin HY, Ni HC, Tseng WI, Gau SS

Abstract
LAY ABSTRACT: Impaired self-regulation (i.e., dysregulation in affective, behavioral, and cognitive control), is commonly present in young people with autism spectrum disorder (ASD). However, little is known about what is happening in people's brains when self-regulation is impaired in young people with ASD. We used a technique called functional MRI (which measures brain activity by detecting changes associated with blood flow) at a resting state (when participants are not asked to do anything) to research this in intellectually able young people with ASD. We found that brains with more connections, especially between regions involved in sensorimotor processing and regions involved in the processes that enable peoples to focus their attention on the most pertinent features from the sensory environment (salience processing), were related to more impaired self-regulation in young people with and without ASD. We also found that impaired self-regulation was related to increased communication within the brain system involved in voluntary orienting attention to a sensory cue (the dorsal attention network) in young people with ASD. These results highlight how different people have different degrees of dysregulation, which has been largely overlooked in the earlier brain imaging reports on ASD. This might contribute to understanding some of the inconsistencies in the existing published literature on this topic.

PMID: 31958997 [PubMed - as supplied by publisher]

Neurochemical and brain functional changes in the ventromedial prefrontal cortex of first-episode psychosis patients: A combined functional magnetic resonance imaging-proton magnetic resonance spectroscopy study.

Wed, 01/22/2020 - 12:00
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Neurochemical and brain functional changes in the ventromedial prefrontal cortex of first-episode psychosis patients: A combined functional magnetic resonance imaging-proton magnetic resonance spectroscopy study.

Aust N Z J Psychiatry. 2020 Jan 20;:4867419898520

Authors: Cen H, Xu J, Yang Z, Mei L, Chen T, Zhuo K, Xiang Q, Song Z, Wang Y, Guo X, Wang J, Jiang K, Xu Y, Li Y, Liu D

Abstract
OBJECTIVE: Previous studies showed alterations of brain function in the ventromedial prefrontal cortex of schizophrenia patients. Also, neurochemical changes, especially GABA level alteration, have been found in the medial prefrontal cortex of schizophrenia patients. However, the relationship between GABA level in the ventromedial prefrontal cortex and brain functional activity in schizophrenia patients remains unexplored.
METHODS: In total, 23 drug-naïve, first-episode psychosis patients and 26 matched healthy controls completed the study. The single voxel proton magnetic resonance spectroscopy data were acquired in ventromedial prefrontal cortex region, which was used as the seed region for resting-state functional connectivity analysis. The proton magnetic resonance spectroscopy data were processed to quantify the concentrations of GABA+, glutamine and glutamate, and N-acetylaspartate in ventromedial prefrontal cortex. Spearman correlation analysis was used to examine the relationship between metabolite concentration, functional connectivity and clinical variables. Pearson correlation analysis was used to examine the relationship between GABA+ concentration and functional connectivity value.
RESULTS: In first-episode psychosis patients, GABA+ level in ventromedial prefrontal cortex was higher and was positively correlated with ventromedial prefrontal cortex-left middle orbital frontal cortex functional connectivity. N-acetylaspartate level was positively correlated with positive symptoms, and the functional connectivity between ventromedial prefrontal cortex and left precuneus was negatively associated with negative symptoms of first-episode psychosis patients.
CONCLUSION: Our results indicated that ventromedial prefrontal cortex functional connectivity changes were positively correlated with higher local GABA+ level in first-episode psychosis patients. The altered neurochemical concentration and functional connectivity provide insights into the pathology of schizophrenia.

PMID: 31958975 [PubMed - as supplied by publisher]

Default mode network connectivity is associated with long-term clinical outcome in patients with schizophrenia.

Wed, 01/22/2020 - 12:00
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Default mode network connectivity is associated with long-term clinical outcome in patients with schizophrenia.

Neuroimage Clin. 2019;22:101805

Authors: Lee H, Lee DK, Park K, Kim CE, Ryu S

Abstract
This study investigated whether resting-state functional connectivity is associated with long-term clinical outcomes of patients with schizophrenia. Resting-state brain images were obtained from 79 outpatients with schizophrenia and 30 healthy controls (HC), using a 3 T-MRI scanner. All patients were 20-50 years old with >3 years' duration of illness and appeared clinically stable. We assessed their psychopathology using the 18-item Brief Psychiatric Rating Scale (BPRS-18) and divided them into "good," "moderate," and "poor" outcome (SZ-GO, SZ-MO, and SZ-PO) groups depending on BPRS-18 total score. We obtained individual functional connectivity maps between a seed region of the bilateral posterior cingulate cortex (PCC) and all other brain regions and compared the functional connectivity of the default mode network (DMN) among the HC and 3 schizophrenia outcome groups, with a voxel-wise threshold of P < .001 within a cluster-extent threshold of 114 voxels. Additionally, we assessed correlations between functional connectivity and BPRS-18 scores. The SZ-MO and SZ-PO groups showed decreased functional connectivity between PCC and right ventromedial prefrontal cortex (vmPFC), left middle cingulate cortex, and left frontopolar cortex (FPC) compared to the SZ-GO and HC groups. DMN connectivity in the right vmPFC and left FPC negatively correlated with subscale scores of the BPRS-18, except the negative symptoms subscale. In this study, poorer clinical outcomes in patients with schizophrenia were associated with decreased DMN connectivity. In particular, the decreased functional connectivity might be related to the severity of positive and mood symptoms rather than negative symptoms.

PMID: 30991621 [PubMed - indexed for MEDLINE]

Adolescent binge drinking disrupts normal trajectories of brain functional organization and personality maturation.

Wed, 01/22/2020 - 12:00
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Adolescent binge drinking disrupts normal trajectories of brain functional organization and personality maturation.

Neuroimage Clin. 2019;22:101804

Authors: Ruan H, Zhou Y, Luo Q, Robert GH, Desrivières S, Quinlan EB, Liu Z, Banaschewski T, Bokde ALW, Bromberg U, Büchel C, Flor H, Frouin V, Garavan H, Gowland P, Heinz A, Ittermann B, Martinot JL, Martinot MP, Nees F, Orfanos DP, Poustka L, Hohmann S, Fröhner JH, Smolka MN, Walter H, Whelan R, Li F, Schumann G, Feng J, IMAGEN Consortium

Abstract
Adolescent binge drinking has been associated with higher risks for the development of many health problems throughout the lifespan. Adolescents undergo multiple changes that involve the co-development processes of brain, personality and behavior; therefore, certain behavior, such as alcohol consumption, can have disruptive effects on both brain development and personality maturation. However, these effects remain unclear due to the scarcity of longitudinal studies. In the current study, we used multivariate approaches to explore discriminative features in brain functional architecture, personality traits, and genetic variants in 19-year-old individuals (n = 212). Taking advantage of a longitudinal design, we selected features that were more drastically altered in drinkers with an earlier onset of binge drinking. With the selected features, we trained a hierarchical model of support vector machines using a training sample (n = 139). Using an independent sample (n = 73), we tested the model and achieved a classification accuracy of 71.2%. We demonstrated longitudinally that after the onset of binge drinking the developmental trajectory of improvement in impulsivity slowed down. This study identified the disrupting effects of adolescent binge drinking on the developmental trajectories of both brain and personality.

PMID: 30991616 [PubMed - indexed for MEDLINE]

Attention network dysfunction underlies memory impairment in posterior cortical atrophy.

Wed, 01/22/2020 - 12:00
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Attention network dysfunction underlies memory impairment in posterior cortical atrophy.

Neuroimage Clin. 2019;22:101773

Authors: Veldsman M, Zamboni G, Butler C, Ahmed S

Abstract
Accumulating evidence suggests that memory is impaired in posterior cortical atrophy (PCA), alongside the early and defining visual disorder. The posterior parietal cortex is a key region of pathology in PCA and memory impairment may be the result of dysfunction of parietally dependent network function rather than the medial temporal lobe dependent dysfunction that defines the storage deficits in typical Alzheimer's disease. We assessed episodic memory performance and network function in16 PCA patients and 19 healthy controls who underwent structural and resting-state functional MRI and neuropsychological testing. Memory was assessed using the Free and Cued Selective Reminding Test (FCSRT), a sensitive test of episodic memory storage and retrieval. We examined correlations between memory performance and functional connectivity in the dorsal attention (DAN) and default mode network (DMN). Immediate recall on the FCSRT was relatively preserved in PCA patients. Total recall performance was impaired in patients relative to healthy controls and performance benefitted from retrieval cues. In patients only, disrupted connectivity in the DAN, but not the DMN, was associated with total recall. Memory impairment may arise from disruption to the dorsal attention network, subserved by the dorsal posterior parietal cortex, a key region of pathology in PCA, rather than classic medial temporal lobe memory circuitry.We propose that functional dysconnectivity in attentional circuits underpins memory impairment in PCA.

PMID: 30991615 [PubMed - indexed for MEDLINE]

Functional Connectivity Fingerprints at Rest Are Similar across Youths and Adults and Vary with Genetic Similarity.

Tue, 01/21/2020 - 17:00
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Functional Connectivity Fingerprints at Rest Are Similar across Youths and Adults and Vary with Genetic Similarity.

iScience. 2019 Dec 25;23(1):100801

Authors: Demeter DV, Engelhardt LE, Mallett R, Gordon EM, Nugiel T, Harden KP, Tucker-Drob EM, Lewis-Peacock JA, Church JA

Abstract
Distinguishing individuals from brain connectivity, and studying the genetic influences on that identification across different ages, improves our basic understanding of functional brain network organization. We applied support vector machine classifiers to two datasets of twins (adult, pediatric) and two datasets of repeat-scan individuals (adult, pediatric). Classifiers were trained on resting state functional connectivity magnetic resonance imaging (rs-fcMRI) data and used to predict individuals and co-twin pairs from independent data. The classifiers successfully identified individuals from a previous scan with 100% accuracy, even when scans were separated by months. In twin samples, classifier accuracy decreased as genetic similarity decreased. Our results demonstrate that classification is stable within individuals, similar within families, and contains similar representations of functional connections over a few decades of life. Moreover, the degree to which these patterns of connections predict siblings' data varied by genetic relatedness, suggesting that genetic influences on rs-fcMRI connectivity are established early in life.

PMID: 31958758 [PubMed - as supplied by publisher]

A 7 Tesla fMRI investigation of human tinnitus percept in cortical and subcortical auditory areas.

Tue, 01/21/2020 - 17:00
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A 7 Tesla fMRI investigation of human tinnitus percept in cortical and subcortical auditory areas.

Neuroimage Clin. 2020 Jan 11;25:102166

Authors: Berlot E, Arts R, Smit J, George E, Gulban OF, Moerel M, Stokroos R, Formisano E, De Martino F

Abstract
Tinnitus is a clinical condition defined by hearing a sound in the absence of an objective source. Early experiments in animal models have suggested that tinnitus stems from an alteration of processing in the auditory system. However, translating these results to humans has proven challenging. One limiting factor has been the insufficient spatial resolution of non-invasive measurement techniques to investigate responses in subcortical auditory nuclei, like the inferior colliculus and the medial geniculate body (MGB). Here we employed ultra-high field functional magnetic resonance imaging (UHF-fMRI) at 7 Tesla to investigate the frequency-specific processing in sub-cortical and cortical regions in a cohort of six tinnitus patients and six hearing loss matched controls. We used task-based fMRI to perform tonotopic mapping and compared the magnitude and tuning of frequency-specific responses between the two groups. Additionally, we used resting-state fMRI to investigate the functional connectivity. Our results indicate frequency-unspecific reductions in the selectivity of frequency tuning that start at the level of the MGB and continue in the auditory cortex, as well as reduced thalamocortical and cortico-cortical connectivity with tinnitus. These findings suggest that tinnitus may be associated with reduced inhibition in the auditory pathway, potentially leading to increased neural noise and reduced functional connectivity. Moreover, these results indicate the relevance of high spatial resolution UHF-fMRI for the investigation of the role of sub-cortical auditory regions in tinnitus.

PMID: 31958686 [PubMed - as supplied by publisher]

Cortical laminar resting-state signal fluctuations scale with the hypercapnic blood oxygenation level-dependent response.

Tue, 01/21/2020 - 17:00
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Cortical laminar resting-state signal fluctuations scale with the hypercapnic blood oxygenation level-dependent response.

Hum Brain Mapp. 2020 Jan 20;:

Authors: Guidi M, Huber L, Lampe L, Merola A, Ihle K, Möller HE

Abstract
Calibrated functional magnetic resonance imaging can remove unwanted sources of signal variability in the blood oxygenation level-dependent (BOLD) response. This is achieved by scaling, using information from a perfusion-sensitive scan during a purely vascular challenge, typically induced by a gas manipulation or a breath-hold task. In this work, we seek for a validation of the use of the resting-state fluctuation amplitude (RSFA) as a scaling factor to remove vascular contributions from the BOLD response. Given the peculiarity of depth-dependent vascularization in gray matter, BOLD and vascular space occupancy (VASO) data were acquired at submillimeter resolution and averaged across cortical laminae. RSFA from the primary motor cortex was, thus, compared to the amplitude of hypercapnia-induced signal changes (tSDhc ) and with the M factor of the Davis model on a laminar level. High linear correlations were observed for RSFA and tSDhc ( R2 = 0.92 ± 0.06) and somewhat reduced for RSFA and M ( R2 = 0.62 ± 0.19). Laminar profiles of RSFA-normalized BOLD signal changes yielded good agreement with corresponding VASO profiles. Overall, this suggests that RSFA contains strong vascular components and is also modulated by baseline quantities contained in the M factor. We conclude that RSFA may replace the scaling factor tSDhc for normalizing the laminar BOLD response.

PMID: 31957959 [PubMed - as supplied by publisher]

Corrigendum: Resting-State Brain Signal Variability in Prefrontal Cortex Is Associated With ADHD Symptom Severity in Children.

Tue, 01/21/2020 - 17:00
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Corrigendum: Resting-State Brain Signal Variability in Prefrontal Cortex Is Associated With ADHD Symptom Severity in Children.

Front Hum Neurosci. 2019;13:431

Authors: Nomi JS, Schettini E, Voorhies W, Bolt TS, Heller AS, Uddin LQ

Abstract
[This corrects the article on p. 90 in vol. 12, PMID: 29593515.].

PMID: 31956303 [PubMed - in process]

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