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Thalamocortical Hyperconnectivity and Amygdala-Cortical Hypoconnectivity in Male Patients With Autism Spectrum Disorder.

Tue, 05/07/2019 - 19:55
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Thalamocortical Hyperconnectivity and Amygdala-Cortical Hypoconnectivity in Male Patients With Autism Spectrum Disorder.

Front Psychiatry. 2019;10:252

Authors: Iidaka T, Kogata T, Mano Y, Komeda H

Abstract
Background: Analyses of resting-state functional magnetic resonance imaging (rs-fMRI) have been performed to investigate pathophysiological changes in the brains of patients with autism spectrum disorder (ASD) relative to typically developing controls (CTLs). However, the results of these previous studies, which have reported mixed patterns of hypo- and hyperconnectivity, are controversial, likely due to the small sample sizes and limited age range of included participants. Methods: To overcome this issue, we analyzed multisite neuroimaging data from a large sample (n = 626) of male participants aged between 5 and 29 years (mean age = 13 years). The rs-fMRI data were preprocessed using SPM12 and DPARSF software, and signal changes in 90 brain regions were extracted. Multiple linear regression was used to exclude the effect of site differences in connectivity data. Subcortical-cortical connectivity was computed using connectivities in the hippocampus, amygdala, caudate nucleus, putamen, pallidum, and thalamus. Eighty-eight connectivities in each structure were compared between patients with ASD and CTLs using multiple linear regression with group, age, and age × group interactions, head movement parameters, and overall connectivity as variables. Results: After correcting for multiple comparisons, patients in the ASD group exhibited significant increases in connectivity between the thalamus and 19 cortical regions distributed throughout the fronto-parietal lobes, including the temporo-parietal junction and posterior cingulate cortices. In addition, there were significant decreases in connectivity between the amygdala and six cortical regions. The mean effect size of hyperconnectivity (0.25) was greater than that for hypoconnectivity (0.08). No other subcortical structures showed significant group differences. A group-by-age interaction was observed for connectivity between the thalamus and motor-somatosensory areas. Conclusions: These results demonstrate that pathophysiological changes associated with ASD are more likely related to thalamocortical hyperconnectivity than to amygdala-cortical hypoconnectivity. Future studies should examine full sets of clinical and behavioral symptoms in combination with functional connectivity to explore possible biomarkers for ASD.

PMID: 31057443 [PubMed]

A Reduction in Video Gaming Time Produced a Decrease in Brain Activity.

Tue, 05/07/2019 - 19:55
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A Reduction in Video Gaming Time Produced a Decrease in Brain Activity.

Front Hum Neurosci. 2019;13:134

Authors: Gong D, Yao Y, Gan X, Peng Y, Ma W, Yao D

Abstract
This study examines whether a decrease in brain development is observable after players have reduced their video gaming time over a period of 1 year. Both video gaming experts and non-experts were recruited, whose resting-state functional MRI (fMRI) data were collected at the beginning and the end of the study. Immediately after the first scan, the participants were instructed to spend no more than 3 h on video gaming weekly for 1 year. The results showed decreased self-reported video gaming skills and decreased amplitude of low-frequency fluctuation (ALFF) in the experts at the end of the study, demonstrating that a reduction in video gaming time over a period of 1 year produced a decrease in brain development. The non-experts served as a control group and had no significant changes. The findings support the adaptive effect of video gaming experience on brain and cognitive development.

PMID: 31057383 [PubMed]

Robust Motion Regression of Resting-State Data Using a Convolutional Neural Network Model.

Tue, 05/07/2019 - 19:55
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Robust Motion Regression of Resting-State Data Using a Convolutional Neural Network Model.

Front Neurosci. 2019;13:169

Authors: Yang Z, Zhuang X, Sreenivasan K, Mishra V, Cordes D, Alzheimer’s Disease Neuroimaging Initiative

Abstract
Resting-state functional magnetic resonance imaging (rs-fMRI) based on the blood-oxygen-level-dependent (BOLD) signal has been widely used in healthy individuals and patients to investigate brain functions when the subjects are in a resting or task-negative state. Head motion considerably confounds the interpretation of rs-fMRI data. Nuisance regression is commonly used to reduce motion-related artifacts with six motion parameters estimated from rigid-body realignment as regressors. To further compensate for the effect of head movement, the first-order temporal derivatives of motion parameters and squared motion parameters were proposed previously as possible motion regressors. However, these additional regressors may not be sufficient to model the impact of head motion because of the complexity of motion artifacts. In addition, while using more motion-related regressors could explain more variance in the data, the neural signal may also be removed with increasing number of motion regressors. To better model how in-scanner motion affects rs-fMRI data, a robust and automated convolutional neural network (CNN) model is developed in this study to obtain optimal motion regressors. The CNN network consists of two temporal convolutional layers and the output from the network are the derived motion regressors used in the following nuisance regression. The temporal convolutional layer in the network can non-parametrically model the prolonged effect of head motion. The set of regressors derived from the neural network is compared with the same number of regressors used in a traditional nuisance regression approach. It is demonstrated that the CNN-derived regressors can more effectively reduce motion-related artifacts.

PMID: 31057348 [PubMed]

Predicting full-scale and verbal intelligence scores from functional Connectomic data in individuals with autism Spectrum disorder.

Tue, 05/07/2019 - 01:54
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Predicting full-scale and verbal intelligence scores from functional Connectomic data in individuals with autism Spectrum disorder.

Brain Imaging Behav. 2019 May 04;:

Authors: Dryburgh E, McKenna S, Rekik I

Abstract
Decoding how intelligence is engrained in the human brain construct is vital in the understanding of particular neurological disorders. While the majority of existing studies focus on characterizing intelligence in neurotypical (NT) brains, investigating how neural correlates of intelligence scores are altered by atypical neurodevelopmental disorders, such as Autism Spectrum Disorders (ASD), is almost absent. To help fill this gap, we use a connectome-based predictive model (CPM) to predict intelligence scores from functional connectome data, derived from resting-state functional magnetic resonance imaging (rsfMRI). The utilized model learns how to select the most significant positive and negative brain connections, independently, to predict the target intelligence scores in NT and ASD populations, respectively. In the first step, using leave-one-out cross-validation we train a linear regressor robust to outliers to identify functional brain connections that best predict the target intelligence score (p - value < 0.01). Next, for each training subject, positive (respectively negative) connections are summed to produce single-subject positive (respectively negative) summary values. These are then paired with the target training scores to train two linear regressors: (a) a positive model which maps each positive summary value to the subject score, and (b) a negative model which maps each negative summary value to the target score. In the testing stage, by selecting the same connections for the left-out testing subject, we compute their positive and negative summary values, which are then fed to the trained negative and positive models for predicting the target score. This framework was applied to NT and ASD populations independently to identify significant functional connections coding for full-scale and verbal intelligence quotients in the brain.

PMID: 31055763 [PubMed - as supplied by publisher]

Maternal sensitivity predicts anterior hippocampal functional networks in early childhood.

Tue, 05/07/2019 - 01:54
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Maternal sensitivity predicts anterior hippocampal functional networks in early childhood.

Brain Struct Funct. 2019 May 04;:

Authors: Wang Q, Zhang H, Wee CY, Lee A, Poh JS, Chong YS, Tan KH, Gluckman PD, Yap F, Fortier MV, Rifkin-Graboi A, Qiu A

Abstract
Maternal care influences child hippocampal development. The hippocampus is functionally organized along an anterior-posterior axis. Little is known with regards to the extent maternal care shapes offspring anterior and posterior hippocampal (aHPC, pHPC) functional networks. This study examined maternal behavior, especially maternal sensitivity, at 6 months postpartum in relation to aHPC and pHPC functional networks of children at age 4 and 6 years. Maternal sensitivity was assessed at 6 months via the "Maternal Behavior Q Sort (MBQS) mini for video". Subsequently, 61 and 76 children underwent resting-state functional magnetic resonance imaging (rs-fMRI), respectively, at 4 and 6 years of age. We found that maternal sensitivity assessed at 6 months postpartum was associated with the right aHPC functional networks in children at both 4 and 6 years of age. At age 4 years, maternal sensitivity was associated positively with the right aHPC's functional connectivity with the sensorimotor network and negatively with the aHPC's functional connectivity with the top-down cognitive control network. At 6 years of age, maternal sensitivity was linked positively with the right aHPC's functional connectivity with the visual-processing network. Our findings suggested that maternal sensitivity in infancy has a long-term impact on the anterior hippocampal functional network in preschool children, implicating a potential role of maternal care in shaping child brain development in early life.

PMID: 31055646 [PubMed - as supplied by publisher]

Higher Peripheral Inflammatory Signaling Associated With Lower Resting-State Functional Brain Connectivity in Emotion Regulation and Central Executive Networks.

Tue, 05/07/2019 - 01:54
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Higher Peripheral Inflammatory Signaling Associated With Lower Resting-State Functional Brain Connectivity in Emotion Regulation and Central Executive Networks.

Biol Psychiatry. 2019 Apr 30;:

Authors: Nusslock R, Brody GH, Armstrong CC, Carroll AL, Sweet LH, Yu T, Barton AW, Hallowell ES, Chen E, Higgins JP, Parrish TB, Wang L, Miller GE

Abstract
BACKGROUND: Researchers document bidirectional pathways linking peripheral inflammation and neural circuitries subserving emotion processing and regulation. To extend this work, we present results from two independent studies examining the relationship between inflammation and resting-state functional connectivity (rsFC), as measured by functional magnetic resonance imaging.
METHODS: Study 1 involved 90 rural African American young adults, 25 years of age (52% female), and study 2 involved 82 urban African American youths, 13 to 14 years of age (66% female). Both studies measured circulating inflammatory biomarkers (C-reactive protein, interleukin 6, interleukin 10, tumor necrosis factor alpha), and the measures were averaged to form a composite. Study 2 also enumerated classical monocytes, a key leukocyte subpopulation involved in immune-to-brain signaling. All participants completed a resting-state functional magnetic resonance imaging scan.
RESULTS: Consistent with our prediction, higher scores on the inflammatory composite were associated with lower rsFC within an emotion regulation network in study 1, controlling for sex. Study 2 replicated study 1, showing that higher scores on the inflammatory composite were associated with lower rsFC within the emotion regulation network, controlling for sex, age, and pubertal status, and found a similar pattern for rsFC within a central executive network. Study 2 also found that higher numbers of classical monocytes were associated with lower rsFC within both the emotion regulation and central executive networks. There was no relationship between rsFC in the anterior salience or default mode networks with inflammation in either study.
CONCLUSIONS: With these findings, we document relationships between peripheral inflammation and rsFC within an emotion regulation and central executive network and replicate these associations with the emotion regulation network across two independent samples.

PMID: 31054766 [PubMed - as supplied by publisher]

The CD33 genotype associated cognitive performance was bidirectionally modulated by intrinsic functional connectivity in the Alzheimer's disease spectrum.

Tue, 05/07/2019 - 01:54
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The CD33 genotype associated cognitive performance was bidirectionally modulated by intrinsic functional connectivity in the Alzheimer's disease spectrum.

Biomed Pharmacother. 2019 May 01;115:108903

Authors: Gong L, Xu R, Lan L, Liu D, Shen J, Zhang B, Alzheimer's Disease Neuroimaging Initiative

Abstract
CD33 is a susceptibility locus for late-onset Alzheimer's disease (AD). However, how the neural mechanism of CD33 affects cognition in the AD spectrum population remains unclear. We aimed to investigate the primary and interactive effects of the CD33 (rs3865444) genotype on brain function in patients with AD using global functional connectivity density (gFCD) mapping via resting-state functional magnetic resonance imaging. Furthermore, we used a conditional process analysis to identify the relationship among the CD33 genotype, gFCD, and cognition performance across the AD spectrum population. Compared to cognitively normal (CN) and mild cognitively impaired (MCI) subjects, patients with AD showed higher gFCD in the default mode network, and the CD33 genotype primarily influenced brain function in the fronto-striatal circuit. Importantly, an interaction between the CD33 genotype and AD was observed in the parahippocampal gyrus. During disease progression, the gFCD trajectories of the CD33 A + allele gradually decreased, whereas those of the CD33 CC allele displayed an inverted U-shaped curve. Furthermore, gFCD in the dorsal anterior cingulate cortex positively mediated the relationship between the CD33 genotype and cognition, while gFCD in the precuneus bidirectionally moderated the mediation in the AD spectrum. These findings provide new insights into the neural mechanisms underlying the influence of the CD33 genotype on cognitive performance and highlight the importance of precise therapeutic strategies for high-risk AD populations.

PMID: 31054508 [PubMed - as supplied by publisher]

Aberrant interactions of cortical networks in chronic migraine: A resting-state fMRI study.

Tue, 05/07/2019 - 01:54
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Aberrant interactions of cortical networks in chronic migraine: A resting-state fMRI study.

Neurology. 2019 May 03;:

Authors: Coppola G, Di Renzo A, Petolicchio B, Tinelli E, Di Lorenzo C, Parisi V, Serrao M, Calistri V, Tardioli S, Cartocci G, Schoenen J, Caramia F, Di Piero V, Pierelli F

Abstract
OBJECTIVE: We investigated resting-state (RS)-fMRI using independent component analysis (ICA) to determine the functional connectivity (FC) between networks in chronic migraine (CM) patients and their correlation with clinical features.
METHODS: Twenty CM patients without preventive therapy or acute medication overuse underwent 3T MRI scans and were compared to a group of 20 healthy controls (HC). We used MRI to collect RS data in 3 selected networks, identified using group ICA: the default mode network (DMN), the executive control network (ECN), and the dorsal attention system (DAS).
RESULTS: Compared to HC, CM patients had significantly reduced functional connectivity between the DMN and the ECN. Moreover, in patients, the DAS showed significantly stronger FC with the DMN and weaker FC with the ECN. The higher the severity of headache, the increased the strength of DAS connectivity, and the lower the strength of ECN connectivity.
CONCLUSION: These results provide evidence for large-scale reorganization of functional cortical networks in chronic migraine. They suggest that the severity of headache is associated with opposite connectivity patterns in frontal executive and dorsal attentional networks.

PMID: 31053665 [PubMed - as supplied by publisher]

The effects of high-frequency repetitive transcranial magnetic stimulation on resting-state functional connectivity in obese adults.

Sat, 05/04/2019 - 04:51

The effects of high-frequency repetitive transcranial magnetic stimulation on resting-state functional connectivity in obese adults.

Diabetes Obes Metab. 2019 May 03;:

Authors: Kim SH, Park BY, Byeon K, Park H, Kim Y, Eun YM, Chung JH

Abstract
AIMS: We conducted 4-week randomized, sham-controlled, single-blind, parallel-group trial to examine the effect of repetitive transcranial magnetic stimulation (rTMS) delivered to the left dorsolateral prefrontal cortex (DLPFC) on functional brain connectivity and body weight in adults with obesity.
MATERIALS AND METHODS: Of the 45 volunteers with obesity aged between 18 and 70 years (body mass index [BMI] ≥25 kg/m2 according to the obesity criterion for an Asian population), 36 subjects (54.1±11.0 years, BMI 30.2±3.5 kg/m2 , 77.8 % females) completed the 4 weeks of follow-up with two resting state fMRI scans (20 in the real stimulation and 16 in the sham stimulation group). A total of 8 sessions of high-frequency rTMS targeting the left DLPFC were provided over a period of 4 weeks (5 seconds trains with 25-second inter-train intervals, 10 Hz, 110% motor threshold; 2000 pulses over 20 min).
RESULTS: Participants in the real stimulation group showed significantly greater weight loss from baseline following the 8 session of rTMS (-2.53±2.41 kg vs. 0.38±1.13 kg, P < 0.01). For intrinsic brain connectivity comparisons, the betweenness centrality values within the right frontoparietal network tended to increase with rTMS, and a significant interaction effect was identified for time (pre vs. post) × rTMS (real vs. sham) in the right frontoparietal network (P = 0.031, FDR corrected).
CONCLUSIONS: We observed that rTMS selectively increased the resting state functional connectivity within the right frontoparietal network. Our findings suggest that high-frequency rTMS to the left DLPFC might strengthen the frontoparietal network that orchestrates top-down inhibitory control to reduce food intake. This article is protected by copyright. All rights reserved.

PMID: 31050167 [PubMed - as supplied by publisher]

Motor Control Deficits in Facial Synkinesis Patients: Neuroimaging Evidences of Cerebral Cortex Involvement.

Sat, 05/04/2019 - 04:51

Motor Control Deficits in Facial Synkinesis Patients: Neuroimaging Evidences of Cerebral Cortex Involvement.

Neural Plast. 2019;2019:7235808

Authors: Wu JJ, Lu YC, Zheng MX, Hua XY, Xu JG, Ding W, Shan CL

Abstract
Objective: Facial synkinesis is a severe sequelae of facial nerve malfunction. Once the synkinesis is established, it is extremely difficult for patients to recover. Given that the restoration of motor or sensory function after peripheral nerve injury was closely related with cortical plasticity, we investigated cortical plasticity in facial synkinesis patients by the frequency-specific data which remains largely uncharacterized.
Materials and Methods: Resting-state fMRI was conducted in 20 facial synkinesis patients and 19 healthy controls, and the amplitude of low-frequency fluctuation (ALFF) in five different frequency bands (slow-6: 0-0.01 Hz; slow-5: 0.01-0.027 Hz; slow-4: 0.027-0.073 Hz; slow-3: 0.073-0.167 Hz; and slow-2: 0.167-0.25 Hz) was calculated, respectively. And the relationship between ALFF and clinical outcomes was also analyzed.
Results: Comparing with the healthy controls, facial synkinesis patients showed significantly different ALFF values, mainly in the sensorimotor areas. Furthermore, increased ALFF of the ipsilateral insula in the slow-6 band was significantly related with better facial nerve function.
Conclusion: Increased ALFF values in the ipsilateral insula might reflect an abnormal state of hypercompensation in motor control of facial synkinesis patients. It provided valuable spatial information about the functionally aberrant regions, which implied the possible involvement of motor control system in facial synkinesis.

PMID: 31049055 [PubMed - in process]

Comparing the Wada Test and Functional MRI for the Presurgical Evaluation of Memory in Temporal Lobe Epilepsy.

Sat, 05/04/2019 - 04:51
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Comparing the Wada Test and Functional MRI for the Presurgical Evaluation of Memory in Temporal Lobe Epilepsy.

Curr Neurol Neurosci Rep. 2019 May 01;19(6):31

Authors: Massot-Tarrús A, White K, Mirsattari SM

Abstract
PURPOSE OF REVIEW: The usefulness of the Wada test (WT) predicting memory impairment from temporal lobe epilepsy (TLE) surgery has been debated, and it has progressively been replaced by functional MRI (fMRI). We review the current role of WT and fMRI in the presurgical assessment of TLE, and how novel surgical techniques might improve cognitive outcomes.
RECENT FINDINGS: fMRI's ability to predict global amnesia has not been assessed. Although WT can produce false-positive results, it is still indicated in patients at risk for developing global amnesia: those with significant bilateral or contralateral memory deficits. In the current review, WT exhibited no added value, beyond preclinical data, for predicting material-specific memory impairment, whereas fMRI was reliable for either verbal or non-verbal memory decline. Abnormal functional connectivity on resting state fMRI (rs-fMRI) between the posterior cingulate and the hippocampus may be a predictor of postsurgical memory outcomes. Restricted resections to the pathogenic tissue, stereotactic laser, radiosurgery, and SEEG-guided thermos-coagulation were associated with better cognitive outcome. fMRI should be used routinely in the presurgical workup of TLE to predict verbal and/or non-verbal memory decline, whereas WT may be indicated when there is a high risk of postsurgical global amnesia. Rs-fMRI is a promising tool for the presurgical workup of TLE, and more restricted resections are recommended to enhance cognitive outcomes.

PMID: 31044310 [PubMed - in process]

Unilateral thalamic glioma disrupts large-scale functional architecture of human brain during resting state.

Sat, 05/04/2019 - 04:51
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Unilateral thalamic glioma disrupts large-scale functional architecture of human brain during resting state.

Neuropsychiatr Dis Treat. 2019;15:947-956

Authors: Li S, Gao L, Liu Y, Ao Y, Xu H

Abstract
Background: The thalamus is an important deep brain structure for the synchronization of brain rhythm and the integration of cortical activity. Human brain imaging and computational modeling have non-invasively revealed its role in maintaining the cortical network architecture and functional hierarchy.
Purpose: The objective of this study was to identify the effect of unilateral thalamic damage on the human brain intrinsic functional architecture.
Patients and methods: We collected an 8-minute resting-state functional magnetic resonance imaging (R-fMRI) data on a 3.0 T magnetic resonance scanner for all the participants: a preoperative patient with left thalamus destroyed by anaplastic astrocytoma (WHO grade III type of astrocytoma) and 20 matched healthy controls. The R-fMRI data was analyzed for functional connectivity and amplitude of spontaneous fluctuations.
Results: The patient showed prominent decrease in functional connectivity within primary sensory networks and advanced cognitive networks, and extensive alterations in between-network coupling. Further analysis of the amplitude of spontaneous activity suggested significant decrease especially in the topographies of default mode network and the Papez circuit.
Conclusion: This result provided evidence about the consequences of thalamic destruction on the correlation and landscape of spontaneous brain activity, promoting our understanding of the effects of thalamic damage on large-scale brain networks.

PMID: 31043784 [PubMed]

Editorial: Functional and Structural Connectomics of Mood Disorders.

Thu, 05/02/2019 - 22:50
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Editorial: Functional and Structural Connectomics of Mood Disorders.

Front Psychiatry. 2019;10:202

Authors: Anand A

PMID: 31040798 [PubMed]

Lower Posttraumatic α-Synuclein Level Associated With Altered Default Mode Network Connectivity Following Acute Mild Traumatic Brain Injury.

Thu, 05/02/2019 - 22:50
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Lower Posttraumatic α-Synuclein Level Associated With Altered Default Mode Network Connectivity Following Acute Mild Traumatic Brain Injury.

Front Neural Circuits. 2019;13:26

Authors: Ye L, Zhang D, Shao M, Zhao P, Yin B, Zhuang J, Wang F, Yan Z, Bai G

Abstract
This study aimed to investigate the changes of α-synuclein in serum and its relationship with default mode network (DMN) connectivity after acute mild traumatic brain injury (mild TBI). Fifty-two patients with mild TBI at the acute phase and 47 matched healthy controls were enrolled in the study. All participants received resting-state functional magnetic resonance imaging (fMRI) and neuropsychological assessments. Relations between the levels of α-synuclein in serum and clinical assessments were obtained using multivariate linear regression. Results showed that the patients with lower α-synuclein presented more complaints on post-concussion symptoms and depression. Moreover, patients with high levels of α-synuclein exhibited significantly decreased functional connectivity in the left precuneus and increased functional connectivity in both the left anterior cingulate cortex and ventro-medial prefrontal cortex (MPFC) compared with patients with low levels of α-synuclein. These findings supported that α-synuclein may modulate the functional connectivity within the DMN and suggest the feasibility of using α-synuclein as an objective biomarker for diagnosis and prognosis of mild TBI.

PMID: 31040769 [PubMed - in process]

A study on changes of the resting-state brain function network in patients with amnestic mild cognitive impairment.

Wed, 05/01/2019 - 22:49
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A study on changes of the resting-state brain function network in patients with amnestic mild cognitive impairment.

Braz J Med Biol Res. 2019;52(5):e8244

Authors: Min J, Zhou XX, Zhou F, Tan Y, Wang WD

Abstract
This study aimed to explore the structural and functional characteristics of the neural network of resting-state brain activities in patients with amnestic mild cognitive impairment (aMCI) by functional magnetic resonance imaging (fMRI) technology. Resting state fMRI scanning was performed on 10 clinically diagnosed aMCI patients and 10 healthy volunteers, and the difference in the resting-state brain activities between aMCI patients and healthy volunteers was compared using the brain function network regional homogeneity (ReHo) analysis method. Results of the ReHo analysis of aMCI patients and healthy volunteers revealed that the ReHo value significantly increased in the posterior cingulate gyrus region, medial frontal lobe, medial cortex of the prefrontal lobe, and part of the parietal lobe. Compared with the normal elderlies, ReHo decreased in aMCI patients in the left temporal lobe (middle temporal gyrus and inferior temporal gyrus), left parahippocampal gyrus, occipital lobe, lingual gyrus, precuneus, and other regions while ReHo increased in regions of the right frontal lobe (inferior frontal gyrus), left superior temporal gyrus, precentral gyrus (frontal lobe), right thalamus, left fusiform gyrus, and other regions. In the resting state, there may be regional abnormalities in brain functional areas in aMCI patients, which may be associated with cognitive impairment.

PMID: 31038547 [PubMed - in process]

Multifaceted integration - memory for faces is subserved by widespread connections between visual, memory, auditory and social networks.

Wed, 05/01/2019 - 22:49
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Multifaceted integration - memory for faces is subserved by widespread connections between visual, memory, auditory and social networks.

J Neurosci. 2019 Apr 29;:

Authors: Ramot M, Walsh C, Martin A

Abstract
Our ability to recognize others by their facial features is at the core of human social interaction, yet this ability varies widely within the general population, ranging from developmental prosopagnosia to "super-recognizers". Previous work has focused mainly on the contribution of neural activity within the well described face network to this variance. However, given the nature of face memory in everyday life, and the social context in which it takes place, we were interested in exploring how the collaboration between different networks outside the face network in humans (measured through resting state connectivity) affects face memory performance. 50 participants (men and women) were scanned with fMRI. Our data revealed that although the nodes of the face processing network were tightly coupled at rest, the strength of these connections did not predict face memory performance. Instead, face recognition memory was dependent on multiple connections between these face patches and regions of the medial temporal lobe memory system (including the hippocampus), and the social processing system. Moreover, this network was selective for memory for faces, and did not predict memory for other visual objects (cars). These findings suggest that in the general population, variability in face memory is dependent on how well the face processing system interacts with other processing networks, with interaction among the face patches themselves accounting for little of the variance in memory ability.SIGNIFICANCE STATEMENTOur ability to recognize and remember faces is one of the pillars of human social interaction. Face recognition however is a very complex skill, requiring specialized neural resources in visual cortex, as well as memory, identity and social processing, all of which are inherent in our real-world experience of faces. Yet in the general population, people vary greatly in their face memory abilities. Here we show that in the neural domain this variability is underpinned by the integration of visual, memory and social circuits, with the strength of the connections between these circuits directly linked to face recognition ability.

PMID: 31036762 [PubMed - as supplied by publisher]

Differential language network functional connectivity alterations in Alzheimer's disease and the semantic variant of primary progressive aphasia.

Tue, 04/30/2019 - 19:48
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Differential language network functional connectivity alterations in Alzheimer's disease and the semantic variant of primary progressive aphasia.

Cortex. 2019 Apr 03;117:284-298

Authors: Montembeault M, Chapleau M, Jarret J, Boukadi M, Laforce R, Wilson MA, Rouleau I, Brambati SM

Abstract
Patients with Alzheimer's disease (AD) and semantic variant primary progressive aphasia (svPPA) can present with similar language impairments, mainly in naming. It has been hypothesized that these deficits are associated with different brain mechanisms in each disease, but no previous study has used a network approach to explore this hypothesis. The aim of this study was to compare resting-state functional magnetic resonance imaging (rs-fMRI) language network in AD, svPPA patients, and cognitively unimpaired elderly adults (CTRL). Therefore, 10 AD patients, 12 svPPA patients and 11 CTRL underwent rs-fMRI. Seed-based functional connectivity analyses were conducted using regions of interest in the left anterior temporal lobe (ATL), left posterior middle temporal gyrus (pMTG) and left inferior frontal gyrus (IFG), applying a voxelwise correction for gray matter volume. In AD patients, the left pMTG was the only key language region showing functional connectivity changes, mainly a reduced interhemispheric functional connectivity with its right-hemisphere counterpart, in comparison to CTRL. In svPPA patients, we observed a functional isolation of the left ATL, both decreases and increases in functional connectivity from the left pMTG and increased functional connectivity form the left IFG. Post-hoc analyses showed that naming impairments were overall associated with the functional disconnections observed across the language network. In conclusion, AD and svPPA patients present distinct language network functional connectivity profiles. In AD patients, functional connectivity changes were restricted to the left pMTG and were overall less severe in comparison to svPPA patients. Results in svPPA patients suggest decreased functional connectivity along the ventral language pathway and increased functional connectivity along the dorsal language pathway. Finally, the observed connectivity patterns are overall consistent with previously reported structural connectivity and language profiles in these patients.

PMID: 31034993 [PubMed - as supplied by publisher]

Resting State Functional Connectivity of the Supplementary Motor Area to Motor and Language Networks in Patients with Brain Tumors.

Tue, 04/30/2019 - 19:48
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Resting State Functional Connectivity of the Supplementary Motor Area to Motor and Language Networks in Patients with Brain Tumors.

J Neuroimaging. 2019 Apr 29;:

Authors: Bathla G, Gene MN, Peck KK, Jenabi M, Tabar V, Holodny AI

Abstract
BACKGROUND AND PURPOSE: We examined the resting-state functional connectivity (RSFC) of the supplementary motor area (SMA) in brain tumor patients. We compared the SMA subdivisions (pre-SMA, SMA proper, central SMA) in terms of RSFC projected from each region to the motor gyrus and language areas.
METHODS: We retrospectively identified 14 brain tumor patients who underwent task-based and resting-state fMRI, and who completed motor and language paradigms that activated the SMA proper and pre-SMA, respectively. Regions of interest (ROIs) obtained from task-based fMRI were generated in both areas and the central SMA to produce RSFC maps. Degree of RSFC was measured from each subdivision to the motor gyrus and Broca's area (BA).
RESULTS: All patients showed RSFC between the pre-SMA and language centers and between the SMA proper and motor gyrus. Thirteen of 14 patients showed RSFC from the central SMA to both motor and language areas. There was no significant difference between subdivisions in degree of RSFC to BA (pre-SMA, r = .801; central SMA, r = .803; SMA proper; r = .760). The pre-SMA showed significantly less RSFC to the motor gyrus (r = .732) compared to the central SMA (r = .842) and SMA proper (r = .883) (P = .016, P = .001, respectively).
CONCLUSIONS: The region between the pre-SMA and SMA proper produces reliable RSFC to the motor gyrus and language areas in brain tumor patients. This study is the first to examine RSFC of the central SMA in this population. Consequently, our results provide further validation to previous studies, supporting the existence of a central SMA with connectivity to both motor and language networks.

PMID: 31034698 [PubMed - as supplied by publisher]

Cerebral circulation time derived from fMRI signals in large blood vessels.

Tue, 04/30/2019 - 19:48
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Cerebral circulation time derived from fMRI signals in large blood vessels.

J Magn Reson Imaging. 2019 Apr 29;:

Authors: Yao JF, Wang JH, Yang HS, Liang Z, Cohen-Gadol AA, Rayz VL, Tong Y

Abstract
BACKGROUND: The systemic low-frequency oscillation (sLFO) functional (f)MRI signals extracted from the internal carotid artery (ICA) and the superior sagittal sinus (SSS) are found to have valuable physiological information.
PURPOSE: 1) To further develop and validate a method utilizing these signals to measure the delay times from the ICAs and the SSS. 2) To establish the delay time as an effective perfusion biomarker that associates with cerebral circulation time (CCT). 3) To explore within subject variations, and the effects of gender and age on the delay times.
STUDY TYPE: Prospective.
SUBJECTS: In all, 100 healthy adults (Human Connectome Project [HCP], age range 22-36 years, 54 females and 46 males), 56 healthy children (Adolescent Brain Cognitive Development project) were included.
FIELD STRENGTH/SEQUENCE: Echo planar imaging (EPI) sequence at 3T.
ASSESSMENT: The sLFO fMRI signals from the ICAs and the SSSs were extracted from the resting state fMRI data. The maximum cross-correlation coefficients and their corresponding delay times were calculated. The gender and age differences of delay times were assessed statistically.
STATISTICAL TESTS: T-tests were conducted to measure the gender differences. The Kruskal-Wallis test was used to detect age differences.
RESULTS: Consistent and robust results were found from 80% of the 400 HCP scans included. Negative correlations (-0.67) between the ICA and the SSS signals were found with the ICA signal leading the SSS signal by ∼5 sec. Within subject variation was 2.23 sec at the 5% significance level. The delay times were not significantly different between genders (P = 0.9846, P = 0.2288 for the left and right ICA, respectively). Significantly shorter delay times (4.3 sec) were found in the children than in the adults (P < 0.01).
DATA CONCLUSION: We have shown that meaningful perfusion information (ie, CCT) can be derived from the sLFO fMRI signals of the large blood vessels.
LEVEL OF EVIDENCE: 1 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2019.

PMID: 31034667 [PubMed - as supplied by publisher]

Differences in functional brain alterations driven by right or left facial nerve efferent dysfunction: Evidence from early Bell's palsy.

Tue, 04/30/2019 - 19:48
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Differences in functional brain alterations driven by right or left facial nerve efferent dysfunction: Evidence from early Bell's palsy.

Quant Imaging Med Surg. 2019 Mar;9(3):427-439

Authors: Han X, Li H, Du L, Wang X, Zhu Y, Yu H, Song T, Sun S, Guo R, Liu J, Shi S, Fu C, Gao W, Zhang L, Yan R, Ma G

Abstract
Background: Bell's palsy is defined as idiopathic unilateral facial nerve palsy. Early Bell's palsy is characterized by emerging asymmetric motor conduction of the facial nerve and obvious imbalance of facial muscle movement, which can result in a substantial psychological impact on patients and trigger brain cortical functional reorganization. However, the differences between the brain functional alterations were driven by right or left facial nerve efferent dysfunction in patients with early Bell's palsy are not fully understood. The neuroimage study in patients with different-sided Bell's palsy in the early stage will help to understand the different mechanisms involved in functional integration driven by unilateral facial efferent nerve dysfunction and to provide the theoretical foundation for the choice of suitable treatment strategy.
Methods: Sixty-seven patients and 37 age- and sex-matched healthy controls were recruited to undergo resting-state functional magnetic resonance imaging (R-fMRI). Regional brain activity was analyzed by comparing the fractional amplitude of low-frequency fluctuations (fALFF) between right palsy and healthy control, left palsy and healthy control, and right and left palsy groups. The altered brain regions were further selected as seeds in subsequent functional connectivity (FC) analysis, and the correlations between the Toronto Facial Grading System (TFGS) scores and the connectivity alterations were also analyzed.
Results: The right and left Bell's palsy groups showed fALFF alterations compared with the healthy control group, and several brain regions with different fALFF values between the right and left palsy groups were identified. In the right palsy group, overall inter-regional FC increased in the right supramarginal gyrus (SMG), bilateral superior frontal gyrus (SFG), and left precentral gyrus (PreCG), compared with the left palsy group. Furthermore, the brain region pairs with higher FC in the right palsy group were left temporal pole of the superior temporal gyrus (TPOsup) and right SMG, left TPOsup and middle cingulate cortex (MCC), left TPOsup and left PreCG, right SMG and SFG, MCC and left PreCG, left and right SFG, and right SFG and left PreCG. In the right palsy group, the left TPOsup and PreCG showed a negative correlation with the TFGS score, while the right SFG and left PreCG showed a positive correlation with the TFGS scores. In the left palsy group, the left TPOsup and right SMG, and the right SMG and SFG region pairs showed a negative correlation with the TFGS score.
Conclusions: The fALFF and FC analyses revealed the remodeling of different brain functional networks driven by right or left facial nerve efferent dysfunction in patients with early Bell's palsy. The reintegration mechanisms differed between patients with right and left Bell's palsy. Additionally, the severity of the disease showed different associations with altered FC.

PMID: 31032190 [PubMed]