New resting-state fMRI related studies at PubMed

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Determinants of Inter-Individual Variability in Corticomotor Excitability Induced by Paired Associative Stimulation.

Tue, 09/03/2019 - 16:20
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Determinants of Inter-Individual Variability in Corticomotor Excitability Induced by Paired Associative Stimulation.

Front Neurosci. 2019;13:841

Authors: Minkova L, Peter J, Abdulkadir A, Schumacher LV, Kaller CP, Nissen C, Klöppel S, Lahr J

Abstract
Transcranial magnetic stimulation (TMS) is a well-established tool in probing cortical plasticity in vivo. Changes in corticomotor excitability can be induced using paired associative stimulation (PAS) protocol, in which TMS over the primary motor cortex is conditioned with an electrical peripheral nerve stimulation of the contralateral hand. PAS with an inter-stimulus interval of 25 ms induces long-term potentiation (LTP)-like effects in cortical excitability. However, the response to a PAS protocol tends to vary substantially across individuals. In this study, we used univariate and multivariate data-driven methods to investigate various previously proposed determinants of inter-individual variability in PAS efficacy, such as demographic, cognitive, clinical, neurophysiological, and neuroimaging measures. Forty-one right-handed participants, comprising 22 patients with amnestic mild cognitive impairment (MCI) and 19 healthy controls (HC), underwent the PAS protocol. Prior to stimulation, demographic, genetic, clinical, as well as structural and resting-state functional MRI data were acquired. The two groups did not differ in any of the variables, except by global cognitive status. Univariate analysis showed that only 61% of all participants were classified as PAS responders, irrespective of group membership. Higher PAS response was associated with lower TMS intensity and with higher resting-state connectivity within the sensorimotor network, but only in responders, as opposed to non-responders. We also found an overall positive correlation between PAS response and structural connectivity within the corticospinal tract, which did not differ between groups. A multivariate random forest (RF) model identified age, gender, education, IQ, global cognitive status, sleep quality, alertness, TMS intensity, genetic factors, and neuroimaging measures (functional and structural connectivity, gray matter (GM) volume, and cortical thickness as poor predictors of PAS response. The model resulted in low accuracy of the RF classifier (58%; 95% CI: 42 - 74%), with a higher relative importance of brain connectivity measures compared to the other variables. We conclude that PAS variability in our sample was not well explained by factors known to influence PAS efficacy, emphasizing the need for future replication studies.

PMID: 31474818 [PubMed]

Low Frequency Systemic Hemodynamic "Noise" in Resting State BOLD fMRI: Characteristics, Causes, Implications, Mitigation Strategies, and Applications.

Tue, 09/03/2019 - 16:20
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Low Frequency Systemic Hemodynamic "Noise" in Resting State BOLD fMRI: Characteristics, Causes, Implications, Mitigation Strategies, and Applications.

Front Neurosci. 2019;13:787

Authors: Tong Y, Hocke LM, Frederick BB

Abstract
Advances in functional magnetic resonance imaging (fMRI) acquisition have improved signal to noise to the point where the physiology of the subject is the dominant noise source in resting state fMRI data (rsfMRI). Among these systemic, non-neuronal physiological signals, respiration and to some degree cardiac fluctuations can be removed through modeling, or in the case of newer, faster acquisitions such as simultaneous multislice acquisition, simple spectral filtering. However, significant low frequency physiological oscillation (∼0.01-0.15 Hz) remains in the signal. This is problematic, as it is the precise frequency band occupied by the neuronally modulated hemodynamic responses used to study brain connectivity, precluding its removal by spectral filtering. The source of this signal, and its method of production and propagation in the body, have not been conclusively determined. Here, we summarize the defining characteristics of the systemic low frequency noise signal, and review some current theories about the signal source and the evidence supporting them. The strength and distribution of the systemic LFO signal make characterizing and removing it essential for accurate quantification, especially for resting state connectivity, when no stimulation can be compared with the signal. Widespread correlated non-neuronal signals obscure and distort the more localized patterns of neuronal correlations between interacting brain regions; they may even cause apparent connectivity between regions with no neuronal interaction. Here, we discuss a simple method we have developed to parse the global, moving, blood-borne signal from the stationary, neuronal connectivity signals, substantially reducing the negative correlations that result from global signal regression. Finally, we will discuss some of the uses to which the moving systemic low frequency oscillation can be put if we consider it a "signal" carrying information, rather than simply "noise" complicating the interpretation of resting state connectivity. Properly utilizing this signal may offer insights into subtle hemodynamic alterations that can be used as early indicators of circulatory dysfunction in a number of neuropsychiatric conditions, such as prodromal stroke, moyamoya, and Alzheimer's disease.

PMID: 31474815 [PubMed]

Altered resting-state functional connectivity in depressive disorder patients with suicidal attempts.

Tue, 09/03/2019 - 16:20
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Altered resting-state functional connectivity in depressive disorder patients with suicidal attempts.

Neurosci Lett. 2019 03 23;696:174-178

Authors: Lee S, Lee SM, Kang WS, Jahng GH, Ryu CW, Park JK

Abstract
In this study, we attempted to examine the resting state functional connectivity (resting state FC) and its correlation with clinical features in depressed disorder patients with suicidal attempts (SA). A total of 32 individuals participated in this study: 12 depressive disorder patients with SA and 20 healthy controls were included. Resting state FC was investigated between the two groups by region of interest (ROI) to ROI analysis. Then seed to voxel analysis was performed using significant ROIs as a seed. The correlations of significant resting state FC with clinical data were analyzed. The connectivity of anterior division of right parahippocampus-posterior division of left parahippocampus (pPaHCl) and temporooccipital part of right inferior temporal gyrus-right frontal eye field of dorsal attention network (FEFrDAN) were significantly increased, while connectivity of medial frontal cortex (MedFC)-right supplementary motor cortex (SMAr) was significantly decreased in the patients (p-FDR [false discovery rate] <0.05). The patient group showed a stronger connectivity between the pPaHCl and a cluster of voxels in the right uncus as well as FEFrDAN and a cluster of voxels in the right fusiform gyrus (p-FDR <0.05). MedFC and SMAr connectivity showed a negative correlation to suicidal ideation (p-FDR = 0.018). These findings suggest a possible role of altered resting state FC among brain regions in neurobiology of depressive disorder and suicidal ideation.

PMID: 30593872 [PubMed - indexed for MEDLINE]

Enhanced theta-gamma coupling associated with hippocampal volume increase following high-frequency left prefrontal repetitive transcranial magnetic stimulation in patients with major depression.

Tue, 09/03/2019 - 16:20
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Enhanced theta-gamma coupling associated with hippocampal volume increase following high-frequency left prefrontal repetitive transcranial magnetic stimulation in patients with major depression.

Int J Psychophysiol. 2018 11;133:169-174

Authors: Noda Y, Zomorrodi R, Daskalakis ZJ, Blumberger DM, Nakamura M

Abstract
The underlying mechanism of repetitive transcranial magnetic stimulation (rTMS) effects on cognition has not been fully examined. Previously, we have reported the left hippocampal volume increase and theta-gamma coupling (TGC) enhancement associated with working memory improvement following rTMS in depression. This study was aimed to examine whether there is a structure-function relationship in hippocampal neuroplasticity induced by prefrontal rTMS. Thirty-one patients with major depression underwent longitudinal MRI scans and resting-state EEG recordings with the 10-20 system using averaged ear-lobes reference, following 10 sessions of high-frequency rTMS over the left dorsolateral prefrontal cortex. Pearson's correlation analyses were applied for the longitudinal changes among the left and right hippocampal volumes as measured by manual volumetry, theta and gamma spectral powers, and TGC as measured by resting-state EEG. The analyses demonstrated that the left hippocampus volume increases correlated with TGC increases at the left central area (r = 0.576, p = 0.001, N = 31), whereas no significant correlations were observed among changes of right hippocampal volume, right central TGC, bilateral gamma or theta powers. These finding suggests structure-function relationship in rTMS-induced neuroplastic changes mediated through the hippocampus and prefrontal network at the stimulated side. Therefore, high-frequency prefrontal rTMS may exert its cognitive effect through the hippocampal structural-functional neuroplasticity.

PMID: 30318052 [PubMed - indexed for MEDLINE]

Sparse Multiview Task-Centralized Ensemble Learning for ASD Diagnosis Based on Age- and Sex-Related Functional Connectivity Patterns.

Tue, 09/03/2019 - 16:20
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Sparse Multiview Task-Centralized Ensemble Learning for ASD Diagnosis Based on Age- and Sex-Related Functional Connectivity Patterns.

IEEE Trans Cybern. 2019 Aug;49(8):3141-3154

Authors: Wang J, Wang Q, Zhang H, Chen J, Wang S, Shen D

Abstract
Autism spectrum disorder (ASD) is an age- and sex-related neurodevelopmental disorder that alters the brain's functional connectivity (FC). The changes caused by ASD are associated with different age- and sex-related patterns in neuroimaging data. However, most contemporary computer-assisted ASD diagnosis methods ignore the aforementioned age-/sex-related patterns. In this paper, we propose a novel sparse multiview task-centralized (Sparse-MVTC) ensemble classification method for image-based ASD diagnosis. Specifically, with the age and sex information of each subject, we formulate the classification as a multitask learning problem, where each task corresponds to learning upon a specific age/sex group. We also extract multiview features per subject to better reveal the FC changes. Then, in Sparse-MVTC learning, we select a certain central task and treat the rest as auxiliary tasks. By considering both task-task and view-view relationships between the central task and each auxiliary task, we can learn better upon the entire dataset. Finally, by selecting the central task, in turn, we are able to derive multiple classifiers for each task/group. An ensemble strategy is further adopted, such that the final diagnosis can be integrated for each subject. Our comprehensive experiments on the ABIDE database demonstrate that our proposed Sparse-MVTC ensemble learning can significantly outperform the state-of-the-art classification methods for ASD diagnosis.

PMID: 29994137 [PubMed - indexed for MEDLINE]

Vulnerabilities in sequencing and task switching in healthy youth offspring of parents with mood disorders.

Tue, 09/03/2019 - 16:20
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Vulnerabilities in sequencing and task switching in healthy youth offspring of parents with mood disorders.

J Clin Exp Neuropsychol. 2018 08;40(6):606-618

Authors: Singh MK, Leslie SM, Bhattacharjee K, Gross M, Weisman EF, Soudi LM, Phillips OR, Onopa A

Abstract
INTRODUCTION: Visuospatial processing and task switching are impaired in individuals with mood disorders. It is unknown whether early deficits are present before mood symptom on set or are related to risk for a specific type of mood disorder. To investigate, we compared visual attention and task switching during sequencing among never-disordered youth with parental family histories of bipolar (BD) and major depressive disorders (MDD) and healthy controls (HC) with no personal or family history of psychopathology.
METHOD: 8-17-year-old youth of parents with BD (n = 31, "BD-risk"), youth of parents with MDD (n = 49, "MDD-risk"), and demographically similar HC (n = 31, "HC") were examined using the Delis-Kaplan Executive Functioning System Trail Making Test. Seed-based resting-state functional connectivity (RSFC) was collected from a subset of 88 participants (25 BD-risk, 37 MDD-risk, 26 HC) to investigate group differences in RSFC related to visuospatial processing.
RESULTS: BD-risk and MDD-risk offspring had impaired sequencing and task switching, demonstrated by reduced scores on visual scanning, F(2, 108) = 4.12, p = .02, number sequencing, F(2, 88) = 4.75, p = .01, letter sequencing, F(2, 108) = 4.24, p = .02, and number-letter sequencing, F(2, 108) = 4.66, p = .01, compared to scores in HC. RSFC between the posterior cingulate (PCC) and clusters in the subcallosal cortex, amygdala, and hippocampus significantly differed among HC, BD-risk, and MDD-risk groups. PCC-subcallosal/limbic RSFC was positively coupled in the MDD-risk and BD-risk groups and negatively coupled in HCs.
CONCLUSIONS: Youth at familial risk for mood disorders demonstrate visuospatial deficits early in the processing stream. Improved methods for identifying at-risk children with the earliest possible neurocognitive impairments may inform remediation strategies that could prevent mood disorders.

PMID: 29168420 [PubMed - indexed for MEDLINE]

Resting-state fMRI dynamic functional network connectivity and associations with psychopathy traits.

Mon, 09/02/2019 - 15:20
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Resting-state fMRI dynamic functional network connectivity and associations with psychopathy traits.

Neuroimage Clin. 2019 Aug 05;24:101970

Authors: Espinoza FA, Anderson NE, Vergara VM, Harenski CL, Decety J, Rachakonda S, Damaraju E, Koenigs M, Kosson DS, Harenski K, Calhoun VD, Kiehl KA

Abstract
Studies have used resting-state functional magnetic resonance imaging (rs-fMRI) to examine associations between psychopathy and brain connectivity in selected regions of interest as well as networks covering the whole-brain. One of the limitations of these approaches is that brain connectivity is modeled as a constant state through the scan duration. To address this limitation, we apply group independent component analysis (GICA) and dynamic functional network connectivity (dFNC) analysis to uncover whole-brain, time-varying functional network connectivity (FNC) states in a large forensic sample. We then examined relationships between psychopathic traits (PCL-R total scores, Factor 1 and Factor 2 scores) and FNC states obtained from dFNC analysis. FNC over the scan duration was better represented by five states rather than one state previously shown in static FNC analysis. Consistent with prior findings, psychopathy was associated with networks from paralimbic regions (amygdala and insula). In addition, whole-brain FNC identified 15 networks from nine functional domains (subcortical, auditory, sensorimotor, cerebellar, visual, salience, default mode network, executive control and attentional) related to psychopathy traits (Factor 1 and PCL-R scores). Results also showed that individuals with higher Factor 1 scores (affective and interpersonal traits) spend more time in a state with weaker connectivity overall, and changed states less frequently compared to those with lower Factor 1 scores. On the other hand, individuals with higher Factor 2 scores (impulsive and antisocial behaviors) showed more dynamism (changes to and from different states) than those with lower scores.

PMID: 31473543 [PubMed - as supplied by publisher]

Alterations in the functional brain network in a rat model of epileptogenesis: A longitudinal resting state fMRI study.

Mon, 09/02/2019 - 15:20
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Alterations in the functional brain network in a rat model of epileptogenesis: A longitudinal resting state fMRI study.

Neuroimage. 2019 Aug 29;:116144

Authors: Christiaen E, Goossens MG, Raedt R, Descamps B, Larsen LE, Craey E, Carrette E, Vonck K, Boon P, Vanhove C

Abstract
Epilepsy is a neurological disorder characterized by recurrent epileptic seizures. Electrophysiological and neuroimaging studies in patients with epilepsy suggest that abnormal functional brain networks play a role in the development of epilepsy, i.e. epileptogenesis, resulting in the generation of spontaneous seizures and cognitive impairment. In this longitudinal study, we investigated changes in functional brain networks during epileptogenesis in the intraperitoneal kainic acid (IPKA) rat model of temporal lobe epilepsy (TLE) using resting state functional magnetic resonance imaging (rsfMRI) and graph theory. Additionally, we investigated whether these changes are related to the frequency of occurrence of spontaneous epileptic seizures in the chronic phase of epilepsy. Using a 7T MRI system, rsfMRI images were acquired under medetomidine anaesthesia before and 1, 3, 6, 10 and 16 weeks after status epilepticus (SE) induction in 20 IPKA animals and 7 healthy control animals. To obtain a functional network, correlation between fMRI time series of 38 regions of interest (ROIs) was calculated. Then, several graph theoretical network measures were calculated to describe and quantify the network changes. At least 17 weeks post-SE, IPKA animals were implanted with electrodes in the left and right dorsal hippocampus, EEG was measured for 7 consecutive days and spontaneous seizures were counted. Our results show that correlation coefficients of fMRI time series shift to lower values during epileptogenesis, indicating weaker whole brain network connections. Segregation and integration in the functional brain network also decreased, indicating a lower local interconnectivity and a lower overall communication efficiency. Secondly, this study demonstrated that the largest decrease in functional connectivity was observed for the retrosplenial cortex. Finally, post-SE changes in functional connectivity, segregation and integration were correlated with seizure frequency in the IPKA rat model.

PMID: 31473355 [PubMed - as supplied by publisher]

Different exercise modalities relieve pain syndrome in patients with knee osteoarthritis and modulate the dorsolateral prefrontal cortex: a multiple mode MRI study.

Sun, 09/01/2019 - 14:20
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Different exercise modalities relieve pain syndrome in patients with knee osteoarthritis and modulate the dorsolateral prefrontal cortex: a multiple mode MRI study.

Brain Behav Immun. 2019 Aug 28;:

Authors: Liu J, Chen L, Tu Y, Chen X, Hu K, Tu Y, Lin M, Xie G, Chen S, Huang J, Liu W, Wu J, Xiao T, Wilson G, Lang C, Park J, Tao J, Kong J

Abstract
OBJECTIVES: Knee osteoarthritis (KOA) is a common degenerative joint disease with no satisfactory intervention. Recently, both physical and mindfulness exercises have received considerable attention for their implications in KOA pain management, and the dorsolateral prefrontal cortex (DLPFC) has displayed a critical role in pain modulation. This study aimed to comparatively investigate the modulation effects of different exercises using multidisciplinary measurements.
METHODS: 140 KOA patients were randomized into Tai Chi, Baduanjin, stationary cycling, or health education control groups for 12 weeks. Knee Injury and Osteoarthritis Outcome Score (KOOS), resting state functional magnetic resonance imaging (fMRI), structural MRI, and serum biomarkers were measured at baseline and at the end of the study.
RESULTS: We found: 1) increased KOOS pain subscores (pain reduction) and serum programmed cell death protein 1 (PD-1) levels in the three exercise groups compared to the control group; 2) decreased resting state functional connectivity (rsFC) of the DLPFC-supplementary motor area (SMA) and increased rsFC between the DLPFC and anterior cingulate cortex in all exercise groups compared to the control group; 3) significant associations between DLPFC-SMA rsFC with KOOS pain subscores and serum PD-1 levels at baseline; 4) significantly increased grey matter volume in the SMA in the Tai Chi and stationary cycling groups, and a trend towards significant increase in the Baduanjin group compared to the control group; 5) significant DLPFC rsFC differences among different exercise groups; and 6) that baseline DLPFC-SMA rsFC can predict the effect of mind-body exercise on pain improvement in KOA.
CONCLUSION: Our results suggest that different exercises can modulate both common and unique DLPFC (cognitive control) pathways, and altered DLPFC-SMA rsFC is associated with serum biomarker levels. Our findings also highlight the potentials of neuroimaging biomarkers in predicting the therapeutic effect of mind-body exercises on KOA pain.

PMID: 31472246 [PubMed - as supplied by publisher]

Cognitive training and neuroplasticity in mild cognitive impairment (COG-IT): protocol for a two-site, blinded, randomised, controlled treatment trial.

Sun, 09/01/2019 - 14:20
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Cognitive training and neuroplasticity in mild cognitive impairment (COG-IT): protocol for a two-site, blinded, randomised, controlled treatment trial.

BMJ Open. 2019 Aug 30;9(8):e028536

Authors: D'Antonio J, Simon-Pearson L, Goldberg T, Sneed JR, Rushia S, Kerner N, Andrews H, Hellegers C, Tolbert S, Perea E, Petrella J, Doraiswamy M, Devanand D

Abstract
INTRODUCTION: Mild cognitive impairment (MCI) is common in older adults and represents a high-risk group for progression to Alzheimer's disease (AD). Medication trials in MCI have generally failed, but new discoveries with brain plasticity in ageing have led to the study of cognitive training as a potential treatment to improve cognitive abilities. Computerised cognitive training (CCT) involves computerised cognitive exercises that target specific cognitive abilities and neural networks to potentially improve cognitive functioning through neuroplasticity.
METHODS AND ANALYSIS: In a two-site study (New York State Psychiatric Institute/Columbia University Medical Center and Duke University Medical Center), we will randomise 100 patients with MCI (Wechsler Memory Scale-III Logical Memory II score 0-11; Folstein Mini Mental State Examination ≥23) to home-based CCT (suite of exercises: memory, matching, spatial recognition, processing speed) or a home-based active control condition (computerised crossword puzzle training (CPT)) with 12 weeks of intensive training followed by regular booster sessions up to 78 weeks. All patients will receive standard neuropsychological and functional assessments in clinic as well as structural/functional brain MRI scans at study entry and endpoint. We will test if CCT, versus CPT, leads to improved cognitive functioning, transfers to functional ability and tasks of everyday life and impacts hippocampal volume changes and changes in the default mode network of the brain measured by resting-state functional MRI.
ETHICS AND DISSEMINATION: The study will be conducted following ethics approval and written informed consent will be obtained from all subjects. Study results will be disseminated via publication, clinicaltrials.gov, media and conference presentations. This will be the first controlled long-term trial to evaluate the effects of home-based CCT versus computerised CPT on cognitive abilities and functional measures and neural outcomes as determined by MRI indices in patients with MCI. Positive results from trial may support further development of home-based CCT.
TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier (NCT03205709).

PMID: 31471436 [PubMed - in process]

Abnormalities within and beyond the cortico-striato-thalamo-cortical circuitry in medication-free patients with OCD revealed by the fractional amplitude of low-frequency fluctuations and resting-state functional connectivity.

Sat, 08/31/2019 - 13:20
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Abnormalities within and beyond the cortico-striato-thalamo-cortical circuitry in medication-free patients with OCD revealed by the fractional amplitude of low-frequency fluctuations and resting-state functional connectivity.

Neurosci Lett. 2019 Aug 27;:134449

Authors: Gao J, Zhou Y, Yang X, Luo J, Meng F, Zheng D, Li Z

Abstract
Neuroimaging studies of obsessive-compulsive disorder (OCD) often focus on the cortico-striato-thalamo-cortical (CSTC) circuitry, but recent studies have found abnormal spontaneous brain activity in regions outside the CSTC circuitry in patients with OCD using resting-state functional magnetic resonance imaging. Researchers have not clearly determined whether changes in spontaneous brain activity within and beyond the CSTC circuitry coexist in medication-free patients with OCD. To address this question, we recruited 64 medication-free patients with OCD and 60 matched healthy controls (HCs) to investigate their spontaneous brain activity by measuring the fractional amplitude of low-frequency fluctuation (fALFF) and resting-state functional connectivity. Patients with OCD showed increased fALFF values in the left dorsolateral prefrontal cortex (DLPFC) and decreased fALFF values in the right rolandic operculum compared with HCs. Furthermore, patients with OCD exhibited significantly increased functional connectivity between the left DLPFC and the left cerebellum and reduced negative functional connectivity between the right rolandic operculum and the left precuneus. These findings provided new insights into the pathophysiological model of OCD, which may include CSTC circuitry and regions outside this circuitry.

PMID: 31470044 [PubMed - as supplied by publisher]

Correlated Resting-State Functional MRI Activity of Frontostriatal, Thalamic, Temporal, and Cerebellar Brain Regions Differentiates Stroke Survivors with High Compared to Low Depressive Symptom Scores.

Sat, 08/31/2019 - 13:20
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Correlated Resting-State Functional MRI Activity of Frontostriatal, Thalamic, Temporal, and Cerebellar Brain Regions Differentiates Stroke Survivors with High Compared to Low Depressive Symptom Scores.

Neural Plast. 2019;2019:2357107

Authors: Goodin P, Lamp G, Vidyasagar R, Connelly A, Rose S, Campbell BCV, Tse T, Ma H, Howells D, Hankey GJ, Davis S, Donnan G, Carey LM

Abstract
Background: One in three survivors of stroke experience poststroke depression (PSD). PSD has been linked with poorer recovery of function and cognition, yet our understanding of potential mechanisms is currently limited. Alterations in resting-state functional MRI have been investigated to a limited extent. Fluctuations in low frequency signal are reported, but it is unknown if interactions are present between the level of depressive symptom score and intrinsic brain activity in varying brain regions.
Objective: To investigate potential interaction effects between whole-brain resting-state activity and depressive symptoms in stroke survivors with low and high levels of depressive symptoms.
Methods: A cross-sectional analysis of 63 stroke survivors who were assessed at 3 months poststroke for depression, using the Montgomery-Åsberg Depression Rating Scale (MÅDRS-SIGMA), and for brain activity using fMRI. A MÅDRS-SIGMA score of >8 was classified as high depressive symptoms. Fractional amplitude of frequency fluctuations (fALFF) data across three frequency bands (broadband, i.e., ~0.01-0.08; subbands, i.e., slow-5: ~0.01-0.027 Hz, slow-4: 0.027-0.07) was examined.
Results: Of the 63 stroke survivors, 38 were classified as "low-depressive symptoms" and 25 as "high depressive symptoms." Six had a past history of depression. We found interaction effects across frequency bands in several brain regions that differentiated the two groups. The broadband analysis revealed interaction effects in the left insula and the left superior temporal lobe. The subband analysis showed contrasting fALFF response between the two groups in the left thalamus, right caudate, and left cerebellum. Across the three frequency bands, we found contrasting fALFF response in areas within the fronto-limbic-thalamic network and cerebellum.
Conclusions: We provide evidence that fALFF is sensitive to changes in poststroke depressive symptom severity and implicates frontostriatal and cerebellar regions, consistent with previous studies. The use of multiband analysis could be an effective method to examine neural correlates of depression after stroke. The START-PrePARE trial is registered with the Australian New Zealand Clinical Trial Registry, number ACTRN12610000987066.

PMID: 31467520 [PubMed - in process]

In vivo magnetic resonance imaging reveals the effect of gonadal hormones on morphological and functional brain sexual dimorphisms in adult sheep.

Fri, 08/30/2019 - 12:00
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In vivo magnetic resonance imaging reveals the effect of gonadal hormones on morphological and functional brain sexual dimorphisms in adult sheep.

Psychoneuroendocrinology. 2019 Aug 13;109:104387

Authors: Barrière DA, Ella A, Adriaensen H, Roselli CE, Chemineau P, Keller M

Abstract
Sex differences in the brain and behavior are produced by the perinatal action of testosterone, which is converted into estradiol by the enzyme aromatase in the brain. Although magnetic resonance imaging (MRI) has been widely used in humans to study these differences, the use of animal models, where hormonal status can be properly manipulated, is necessary to explore the mechanisms involved. We used sheep, a recognized model in the field of neuroendocrinology, to assess brain morphological and functional sex differences and their regulation by adult gonadal hormones. To this end, we performed voxel-based morphometry and a resting-state functional MRI approach to assess sex differences in gonadally intact animals. We demonstrated significant sex differences in gray matter concentration (GMC) at the level of the gonadotropic axis, i.e., not only within the hypothalamus and pituitary but also within the hippocampus and the amygdala of intact animals. We then performed the same analysis one month after gonadectomy and found that some of these differences were reduced, especially in the hypothalamus and amygdala. By contrast, we found few differences in the organization of the functional connectome between males and females either before or after gonadectomy. As a whole, our study identifies brain regions that are sexually dimorphic in the sheep brain at the resolution of the MRI and highlights the role of gonadal hormones in the maintenance of these differences.

PMID: 31465941 [PubMed - as supplied by publisher]

Enhancement of indirect functional connections with shortest path length in the adult autistic brain.

Fri, 08/30/2019 - 12:00
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Enhancement of indirect functional connections with shortest path length in the adult autistic brain.

Hum Brain Mapp. 2019 Aug 29;:

Authors: Guo X, Simas T, Lai MC, Lombardo MV, Chakrabarti B, Ruigrok ANV, Bullmore ET, Baron-Cohen S, Chen H, Suckling J, MRC AIMS Consortium

Abstract
Autism is a neurodevelopmental condition characterized by atypical brain functional organization. Here we investigated the intrinsic indirect (semi-metric) connectivity of the functional connectome associated with autism. Resting-state functional magnetic resonance imaging scans were acquired from 65 neurotypical adults (33 males/32 females) and 61 autistic adults (30 males/31 females). From functional connectivity networks, semi-metric percentages (SMPs) were calculated to assess the proportion of indirect shortest functional pathways at global, hemisphere, network, and node levels. Group comparisons were then conducted to ascertain differences between autism and neurotypical control groups. Finally, the strength and length of edges were examined to explore the patterns of semi-metric connections associated with autism. Compared with neurotypical controls, autistic adults displayed significantly higher SMP at all spatial scales, similar to prior observations in adolescents. Differences were primarily in weaker, longer-distance edges in the majority between networks. However, no significant diagnosis-by-sex interaction effects were observed on global SMP. These findings suggest increased indirect functional connectivity in the autistic brain is persistent from adolescence to adulthood and is indicative of reduced functional network integration.

PMID: 31464062 [PubMed - as supplied by publisher]

The predictive potential of altered spontaneous brain activity patterns in diabetic retinopathy and nephropathy.

Fri, 08/30/2019 - 12:00
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The predictive potential of altered spontaneous brain activity patterns in diabetic retinopathy and nephropathy.

EPMA J. 2019 Sep;10(3):249-259

Authors: Wang Y, Shao Y, Shi WQ, Jiang L, Wang XY, Zhu PW, Yuan Q, Gao G, Lv JL, Wang GX

Abstract
Objective: The amplitude of low-frequency fluctuation (ALFF) fMRI technique was used to study the changes of spontaneous brain activity in patients with diabetic retinopathy and nephropathy (DRN), and to explore the application of ALFF technique in the potential prediction and the targeted prevention of diabetic microangiopathy.
Methods: Nineteen patients with diabetic retinopathy and nephropathy and 19 healthy controls (HCs) were matched for age and gender. Spontaneous cerebral activity variations were investigated using the ALFF technique. The average ALFF values of the DRN patients and the HCs were classified utilizing receiver operating characteristic (ROC) curves.
Results: In contrast to the results in the HCs, the patients with DRN had significantly higher ALFF values in the cerebellum (bilaterally in the posterior and anterior lobes) and the left inferior temporal gyrus, but the ALFF values of the bilateral medial frontal gyrus, right superior temporal gyrus, right middle frontal gyrus, left middle/inferior frontal gyrus, bilateral precuneus, and left inferior parietal lobule were lower. ROC curve analysis of each brain region showed the accuracy of AUC was excellent. However, the mean ALFF values in the different regions did not correlate with clinical performance. The subjects showed abnormal neuronal synchronization in many areas of the brain, which is consistent with cognitive and visual functional deficits.
Conclusion: Abnormal spontaneous activity was detected in many areas of the brain, which may provide useful information for understanding the pathology of DRN. Abnormal ALFF values of these brain regions may be of predictive value in the development of early DRN and be a targeted intervention indicator for individualized treatment of diabetic microvascular diseases.

PMID: 31462942 [PubMed]

The Beijing Twin Study (BeTwiSt): An Update.

Fri, 08/30/2019 - 12:00
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The Beijing Twin Study (BeTwiSt): An Update.

Twin Res Hum Genet. 2019 Aug 29;:1-6

Authors: Bi D, Li X, Chen J, Jiang N, Zhang J

Abstract
The Beijing Twin Study (BeTwiSt), which was established in 2006, is an ongoing study aiming to investigate the genetic and environmental etiology of adolescent psychopathology. Resting-state brain imaging datasets have been examined for same-sex twins, and other psychological traits and emotional and behavioral variables have been examined for all twins. Based on the registry, the main findings regarding the etiological mechanism underlying adolescent development, magnetic resonance imaging results, and genetic and environmental influences on other psychological traits have been published. This article summarizes the key findings in these three areas and discusses future plans for the BeTwiSt.

PMID: 31462339 [PubMed - as supplied by publisher]

Functional Connectivity of the Precuneus in Unmedicated Patients With Depression.

Fri, 08/30/2019 - 12:00
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Functional Connectivity of the Precuneus in Unmedicated Patients With Depression.

Biol Psychiatry Cogn Neurosci Neuroimaging. 2018 12;3(12):1040-1049

Authors: Cheng W, Rolls ET, Qiu J, Yang D, Ruan H, Wei D, Zhao L, Meng J, Xie P, Feng J

Abstract
BACKGROUND: The precuneus has connectivity with brain systems implicated in depression.
METHODS: We performed the first fully voxel-level resting-state functional connectivity (FC) neuroimaging analysis of depression of the precuneus, with 282 patients with major depressive disorder and 254 control subjects.
RESULTS: In 125 unmedicated patients, voxels in the precuneus had significantly increased FC with the lateral orbitofrontal cortex, a region implicated in nonreward that is thereby implicated in depression. FC was also increased in depression between the precuneus and the dorsolateral prefrontal cortex, temporal cortex, and angular and supramarginal areas. In patients receiving medication, the FC between the lateral orbitofrontal cortex and precuneus was decreased back toward that in the control subjects. In the 254 control subjects, parcellation revealed superior anterior, superior posterior, and inferior subdivisions, with the inferior subdivision having high connectivity with the posterior cingulate cortex, parahippocampal gyrus, angular gyrus, and prefrontal cortex. It was the ventral subdivision of the precuneus that had increased connectivity in depression with the lateral orbitofrontal cortex and adjoining inferior frontal gyrus.
CONCLUSIONS: The findings support the theory that the system in the lateral orbitofrontal cortex implicated in the response to nonreceipt of expected rewards has increased effects on areas in which the self is represented, such as the precuneus. This may result in low self-esteem in depression. The increased connectivity of the precuneus with the prefrontal cortex short-term memory system may contribute to the rumination about low self-esteem in depression. These findings provide evidence that a target to ameliorate depression is the lateral orbitofrontal cortex.

PMID: 30243643 [PubMed - indexed for MEDLINE]

[The correlation of functional connectivity and structural connectivity between hippocampus and thalamus in Alzheimer's disease and amnestic mild cognitive impairment].

Thu, 08/29/2019 - 11:00

[The correlation of functional connectivity and structural connectivity between hippocampus and thalamus in Alzheimer's disease and amnestic mild cognitive impairment].

Zhonghua Nei Ke Za Zhi. 2019 Sep 01;58(9):662-667

Authors: Feng F, Zhou B, Wang L, Yao HX, Guo YE, An NY, Wang LN, Zhang X

Abstract
Objective: To investigate the correlation of functional connectivity (FC) and the integrity of connective fibres between hippocampus and thalamus in Alzheimer's disease(AD) and amnestic mild cognitive impairment (aMCI). Methods: Both resting-state functional magnetic resonance imaging (rs-fMRI) and diffusion tensor imaging (DTI) data of 40 AD patients, 37 aMCI patients and 41 normal control subjects matching with age and educational level were collected. These subjects were all recruited from outpatient Department of Neurology in the Second Medical Center of Chinese PLA General Hospital, as well as poster, from May 2016 to January 2018. The FC strength between bilateral hippocampus and thalamus, as well as the parameters representing integrity of connective fibres, including fractional anisotropy (FA) and mean diffusivity(MD),were analyzed. Also, the correlations between FC strength and FA or MD strength were analyzed in the study. Results: Compared to that of normal control subjects, the FC strength between billateral hippocampus and thalamus in patients with AD, aMCI were not significantly different(P>0.05). The integrity of bilateral connective fibres between hippocampus and thalamus were damaged in AD patients when compared to normal control subjects(P<0.01). A positive correlation of connective fibres integrity with FC strength between hippocampus and thalamus was found in the left side(r=0.25,P<0.05) but rather in the right side. Conclusion: In AD and aMCI patients, structural connectivity between left hippocampus and thalamus affects the functional connectivity between them.

PMID: 31461817 [PubMed - in process]

Lower Functional Connectivity in Vestibular-Limbic Networks in Individuals With Subclinical Agoraphobia.

Thu, 08/29/2019 - 11:00

Lower Functional Connectivity in Vestibular-Limbic Networks in Individuals With Subclinical Agoraphobia.

Front Neurol. 2019;10:874

Authors: Indovina I, Conti A, Lacquaniti F, Staab JP, Passamonti L, Toschi N

Abstract
Background: Agoraphobia was described in 1871 as a condition of fear-related alterations in spatial orientation and locomotor control triggered by places or situations that might cause a patient to panic and feel trapped. In contemporary nosology, however, this original concept of agoraphobia was split into two diagnostic entities, i.e., the modern anxiety disorder of agoraphobia, consisting solely of phobic/avoidant symptoms in public spaces, and the recently defined vestibular disorder of persistent postural perceptual dizziness (PPPD), characterized by dizziness, and unsteadiness exacerbated by visual motion stimuli. Previous neuroimaging studies found altered brain activity and connectivity in visual-vestibular networks of patients with PPPD vs. healthy controls. Neuroticism and introversion, which pre-dispose to both agoraphobia and PPPD, influenced brain responses to vestibular and visual motion stimuli in patients with PPPD. Similar neuroimaging studies have not been undertaken in patients with agoraphobia in its current definition. Given their shared history and pre-disposing factors, we sought to test the hypotheses that individuals with agoraphobic symptoms have alterations in visual-vestibular networks similar to those of patients with PPPD, and that these alterations are influenced by neuroticism and introversion. Methods: Drawing from the Human Connectome Project (HCP) database, we matched 52 participants with sub-clinical agoraphobia and 52 control subjects without agoraphobic symptoms on 19 demographic and psychological/psychiatric variables. We then employed a graph-theoretical framework to compare resting-state functional magnetic resonance images between groups and evaluated the interactive effects of neuroticism and introversion on the brain signatures of agoraphobia. Results: Individuals with subclinical agoraphobia had lower global clustering, efficiency and transitivity relative to controls. They also had lower connectivity metrics in two brain networks, one positioned to process incoming visual space-motion information, assess threat, and initiate/inhibit behavioral responses (visuospatial-emotional network) and one positioned to control and monitor locomotion (vestibular-navigational network). Introversion interacted with agoraphobic symptoms to lower the connectivity of the visuospatial-emotional network. This contrasted with previous findings describing neuroticism-associated higher connectivity in a narrower visual-spatial-frontal network in patients with PPPD. Conclusion: Functional connectivity was lower in two brain networks in subclinical agoraphobia as compared to healthy controls. These networks integrate visual vestibular and emotional response to guide movement in space.

PMID: 31456740 [PubMed]

Resting State fMRI: Going Through the Motions.

Thu, 08/29/2019 - 11:00

Resting State fMRI: Going Through the Motions.

Front Neurosci. 2019;13:825

Authors: Maknojia S, Churchill NW, Schweizer TA, Graham SJ

Abstract
Resting state functional magnetic resonance imaging (rs-fMRI) has become an indispensable tool in neuroscience research. Despite this, rs-fMRI signals are easily contaminated by artifacts arising from movement of the head during data collection. The artifacts can be problematic even for motions on the millimeter scale, with complex spatiotemporal properties that can lead to substantial errors in functional connectivity estimates. Effective correction methods must be employed, therefore, to distinguish true functional networks from motion-related noise. Research over the last three decades has produced numerous correction methods, many of which must be applied in combination to achieve satisfactory data quality. Subject instruction, training, and mild restraints are helpful at the outset, but usually insufficient. Improvements come from applying multiple motion correction algorithms retrospectively after rs-fMRI data are collected, although residual artifacts can still remain in cases of elevated motion, which are especially prevalent in patient populations. Although not commonly adopted at present, "real-time" correction methods are emerging that can be combined with retrospective methods and that promise better correction and increased rs-fMRI signal sensitivity. While the search for the ideal motion correction protocol continues, rs-fMRI research will benefit from good disclosure practices, such as: (1) reporting motion-related quality control metrics to provide better comparison between studies; and (2) including motion covariates in group-level analyses to limit the extent of motion-related confounds when studying group differences.

PMID: 31456656 [PubMed]

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