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

Wed, 01/22/2020 - 22:58
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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]

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

Tue, 01/21/2020 - 22:56
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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 - 22:56
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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 - 22:56
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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]

Targeted Stimulation of Human Orbitofrontal Networks Disrupts Outcome-Guided Behavior.

Tue, 01/21/2020 - 22:56
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Targeted Stimulation of Human Orbitofrontal Networks Disrupts Outcome-Guided Behavior.

Curr Biol. 2020 Jan 07;:

Authors: Howard JD, Reynolds R, Smith DE, Voss JL, Schoenbaum G, Kahnt T

Abstract
Outcome-guided behavior requires knowledge about the current value of expected outcomes. Such behavior can be isolated in the reinforcer devaluation task, which assesses the ability to infer the current value of specific rewards after devaluation. Animal lesion studies demonstrate that orbitofrontal cortex (OFC) is necessary for normal behavior in this task, but a causal role for human OFC in outcome-guided behavior has not been established. Here, we used sham-controlled, non-invasive, continuous theta-burst stimulation (cTBS) to temporarily disrupt human OFC network activity by stimulating a site in the lateral prefrontal cortex that is strongly connected to OFC prior to devaluation of food odor rewards. Subjects in the sham group appropriately avoided Pavlovian cues associated with devalued food odors. However, subjects in the stimulation group persistently chose those cues, even though devaluation of food odors themselves was unaffected by cTBS. This behavioral impairment was mirrored in changes in resting-state functional magnetic resonance imaging (rs-fMRI) activity such that subjects in the stimulation group exhibited reduced OFC network connectivity after cTBS, and the magnitude of this reduction was correlated with choices after devaluation. These findings demonstrate the feasibility of indirectly targeting the human OFC with non-invasive cTBS and indicate that OFC is specifically required for inferring the value of expected outcomes.

PMID: 31956033 [PubMed - as supplied by publisher]

Reorganized functional connectivity of language centers as a possible compensatory mechanism for basal ganglia aphasia.

Tue, 01/21/2020 - 22:56
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Reorganized functional connectivity of language centers as a possible compensatory mechanism for basal ganglia aphasia.

Brain Inj. 2020 Jan 20;:1-8

Authors: Xu L, Huang L, Cui W, Yu Q

Abstract
Primary Object: To investigate the functional connectivity (FC) of cortical language centers in patients who have regained fluent speech after basal ganglia aphasia and identify the possible compensatory mechanism.Methods & Procedures: A retrospective cohort of 12 patients and 17 healthy controls were studied using resting-state functional MRI (rs-fMRI). All patients suffered from an ischemic stroke with lesions confined to the basal ganglia and showed impaired language functions at admission. Seven patients had lesions in the left basal ganglia, three in the right, and two in both sides. The rs-fMRI was performed after the patients regained fluent speech. Broca's area, Wernicke's area, and their contralateral homologues were selected as the region-of-interest (ROI) for both voxel-wise and ROI-wise FC studies.Results: We discovered that the interhemispheric FC of the language centers (i.e. Broca's area and Wernicke's area) decreased and the intrahemispheric FC of the language centers increased in these patients who regained fluent speech after basal ganglia aphasia.Conclusions: We speculated that damages to the basal ganglia disrupted the cortico-subcortical circuits that facilitated the transhemispheric communications of language functions, resulting in decreased interhemispheric FC. Consequently, the intrahemispheric FC increased as a possible compensatory mechanism to restore the language functions.

PMID: 31955634 [PubMed - as supplied by publisher]

Oxytocin effects on the resting-state mentalizing brain network.

Mon, 01/20/2020 - 19:55

Oxytocin effects on the resting-state mentalizing brain network.

Brain Imaging Behav. 2020 Jan 18;:

Authors: Wu H, Feng C, Lu X, Liu X, Liu Q

Abstract
Oxytocin (OT) has modulatory effects in both human behavior and in the brain, which is not limited in the specific brain area but also with the potential effect on connectivity with other brain regions. Evidence indicates that OT effects on human behavior are multifaceted, such as trust behavior, decrease anxiety, empathy and bonding behavior. For the vital role of mentalizing in understanding others, here we examine whether OT has a general effect on mentalizing brain network which is associated to the effect of related social behavioral and personality traits. Using a randomized, double-blind placebo-controlled group design, we investigate the resting-state functional magnetic resonance imaging after intranasal OT or placebo. The functional connectivity (FC) maps with seed in left/right temporoparietal junction (lTPJ/rTPJ) showed that OT significantly increased connectivity between rTPJ and default attention network (DAN), but decreased the FC between lTPJ and medial prefrontal network (MPN). With machine learning approach, we report that identified altered FCs of TPJ can classify OT and placebo (PL) group. Moreover, individual's empathy trait can modulate the FC between left TPJ and right rectus (RECT), which shows a positive correlation with empathic concern in PL group but a negative correlation in OT group. These results demonstrate that OT has significant effect on FC with lTPJ and rTPJ, brain regions where are critical for mentalizing, and the empathy concern can modulate the FC. These findings advance our understanding of the neural mechanisms by which OT modulates social behaviors, especially in social interaction involving mentalizing.

PMID: 31955321 [PubMed - as supplied by publisher]

Abnormal degree centrality in delayed encephalopathy after carbon monoxide poisoning: a resting-state fMRI study.

Mon, 01/20/2020 - 19:55

Abnormal degree centrality in delayed encephalopathy after carbon monoxide poisoning: a resting-state fMRI study.

Neuroradiology. 2020 Jan 18;:

Authors: Wu K, Liu M, He L, Tan Y

Abstract
PURPOSE: To explore neuropathologic mechanisms in functional brain regions in patients with delayed encephalopathy after carbon monoxide poisoning (DEACMP) from the perspective of the brain network nodes by resting-state functional magnetic resonance imaging (rs-fMRI).
METHODS: The fMRI and cognitive assessments were performed in 25 patients with DEACMP and 25 age-, sex- and education-matched healthy controls (HCs). Data analysis was performed via the degree centrality (DC) method. Then, the associations between the cognitive assessments and DC in the identified abnormal brain regions were assessed by using a correlation analysis.
RESULTS: Compared with the HCs, the DEACMP patients displayed significantly decreased DC values in the right superior frontal gyrus, right precentral gyrus, right angular gyrus, right marginal gyrus, right hippocampus, and left thalamus but increased DC values in the right inferior frontal gyrus, right cingulate gyrus, left superior temporal gyrus, left medial temporal gyrus, right lingual gyrus, and right posterior cerebellar lobe, pons, and midbrain (GRF correction, voxel P value < 0.001, cluster P value < 0.01). The correlation analysis in the DEACMP group revealed that there was a negative correlation between the DC values in the right hippocampus and MMSE scores, whereas a positive correlation was observed in the right cingulate gyrus.
CONCLUSIONS: Patients with DEACMP exhibited abnormal degree centrality in the brain network. This finding may provide a new approach for examining the neuropathologic mechanisms underlying DEACMP.

PMID: 31955235 [PubMed - as supplied by publisher]

Aberrant resting-state interhemispheric functional connectivity in patients with postpartum depression.

Mon, 01/20/2020 - 19:55

Aberrant resting-state interhemispheric functional connectivity in patients with postpartum depression.

Behav Brain Res. 2020 Jan 16;:112483

Authors: Zhang S, Wang W, Wang G, Li B, Chai L, Guo J, Gao X

Abstract
The aim of this study is to investigate the alterations of interhemispheric functional connectivity in patients with postpartum depression (PPD) during resting state, and their potential correlations with clinical severity. Twenty- eight patients with PPD and twenty-five matched healthy postpartum (HP) women within 4 weeks after delivery were recruited and performed resting-state functional magnetic resonance imaging(fMRI) scans. Voxel-mirrored homotopic connectivity (VMHC), which is useful for exploring interhemispheric functional connectivity, and has been widely utilized to identify abnormal functional connectivity between the symmetrical brain regions in many diseases, was calculated in the present study, and intergroup VMHC differences in the voxel manner were analyzed. Correlations between VMHC values and clinical variables were also analyzed. Compared with HP, patients with PPD exhibited significantly decreased VMHC values in bilateral dorsomedial prefrontal cortex (dmPFC), dorsal anterior cingulate cortex (dACC) and orbitofrontal cortex (OFC). Furthermore, VMHC values within the dmPFC negatively correlated with the Edinburgh postpartum depression scale (EPDS) score. These findings suggested that functional coordination between several homotopic brain regions were impaired in patients with PPD. This study provided evidences of aberrant interhemispheric connectivity within brain regions involved in the maternal care network in PPD, and may contribute to the further understanding of the neural mechanism underlying PPD.

PMID: 31954737 [PubMed - as supplied by publisher]

Functional brain architecture is associated with the rate of tau accumulation in Alzheimer's disease.

Sun, 01/19/2020 - 19:53
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Functional brain architecture is associated with the rate of tau accumulation in Alzheimer's disease.

Nat Commun. 2020 Jan 17;11(1):347

Authors: Franzmeier N, Neitzel J, Rubinski A, Smith R, Strandberg O, Ossenkoppele R, Hansson O, Ewers M, Alzheimer’s Disease Neuroimaging Initiative (ADNI)

Abstract
In Alzheimer's diseases (AD), tau pathology is strongly associated with cognitive decline. Preclinical evidence suggests that tau spreads across connected neurons in an activity-dependent manner. Supporting this, cross-sectional AD studies show that tau deposition patterns resemble functional brain networks. However, whether higher functional connectivity is associated with higher rates of tau accumulation is unclear. Here, we combine resting-state fMRI with longitudinal tau-PET in two independent samples including 53 (ADNI) and 41 (BioFINDER) amyloid-biomarker defined AD subjects and 28 (ADNI) vs. 16 (BioFINDER) amyloid-negative healthy controls. In both samples, AD subjects show faster tau accumulation than controls. Second, in AD, higher fMRI-assessed connectivity between 400 regions of interest (ROIs) is associated with correlated tau-PET accumulation in corresponding ROIs. Third, we show that a model including baseline connectivity and tau-PET is associated with future tau-PET accumulation. Together, connectivity is associated with tau spread in AD, supporting the view of transneuronal tau propagation.

PMID: 31953405 [PubMed - in process]

Altered resting-state dynamic functional brain networks in major depressive disorder: Findings from the REST-meta-MDD consortium.

Sun, 01/19/2020 - 19:53
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Altered resting-state dynamic functional brain networks in major depressive disorder: Findings from the REST-meta-MDD consortium.

Neuroimage Clin. 2020 Jan 07;:102163

Authors: Long Y, Cao H, Yan C, Chen X, Li L, Castellanos FX, Bai T, Bo Q, Chen G, Chen N, Chen W, Cheng C, Cheng Y, Cui X, Duan J, Fang Y, Gong Q, Guo W, Hou Z, Hu L, Kuang L, Li F, Li K, Li T, Liu Y, Luo Q, Meng H, Peng D, Qiu H, Qiu J, Shen Y, Shi Y, Si T, Wang C, Wang F, Wang K, Wang L, Wang X, Wang Y, Wu X, Wu X, Xie C, Xie G, Xie H, Xie P, Xu X, Yang H, Yang J, Yao J, Yao S, Yin Y, Yuan Y, Zhang A, Zhang H, Zhang K, Zhang L, Zhang Z, Zhou R, Zhou Y, Zhu J, Zou C, Zang Y, Zhao J, Kin-Yuen Chan C, Pu W, Liu Z

Abstract
BACKGROUND: Major depressive disorder (MDD) is known to be characterized by altered brain functional connectivity (FC) patterns. However, whether and how the features of dynamic FC would change in patients with MDD are unclear. In this study, we aimed to characterize dynamic FC in MDD using a large multi-site sample and a novel dynamic network-based approach.
METHODS: Resting-state functional magnetic resonance imaging (fMRI) data were acquired from a total of 460 MDD patients and 473 healthy controls, as a part of the REST-meta-MDD consortium. Resting-state dynamic functional brain networks were constructed for each subject by a sliding-window approach. Multiple spatio-temporal features of dynamic brain networks, including temporal variability, temporal clustering and temporal efficiency, were then compared between patients and healthy subjects at both global and local levels.
RESULTS: The group of MDD patients showed significantly higher temporal variability, lower temporal correlation coefficient (indicating decreased temporal clustering) and shorter characteristic temporal path length (indicating increased temporal efficiency) compared with healthy controls (corrected p < 3.14×10-3). Corresponding local changes in MDD were mainly found in the default-mode, sensorimotor and subcortical areas. Measures of temporal variability and characteristic temporal path length were significantly correlated with depression severity in patients (corrected p < 0.05). Moreover, the observed between-group differences were robustly present in both first-episode, drug-naïve (FEDN) and non-FEDN patients.
CONCLUSIONS: Our findings suggest that excessive temporal variations of brain FC, reflecting abnormal communications between large-scale bran networks over time, may underlie the neuropathology of MDD.

PMID: 31953148 [PubMed - as supplied by publisher]

Forced conceptual thought induced by electrical stimulation of the left prefrontal gyrus involves widespread neural networks.

Sat, 01/18/2020 - 19:52

Forced conceptual thought induced by electrical stimulation of the left prefrontal gyrus involves widespread neural networks.

Epilepsy Behav. 2020 Jan 14;104(Pt A):106644

Authors: Liu A, Friedman D, Barron DS, Wang X, Thesen T, Dugan P

Abstract
BACKGROUND: Early accounts of forced thought were reported at the onset of a focal seizure, and characterized as vague, repetitive, and involuntary intellectual auras distinct from perceptual or psychic hallucinations or illusions. Here, we examine the neural underpinnings involved in conceptual thought by presenting a series of 3 patients with epilepsy reporting intrusive thoughts during electrical stimulation of the left lateral prefrontal cortex (PFC) during invasive surgical evaluation. We illustrate the widespread networks involved through two independent brain imaging modalities: resting state functional magnetic resonance imaging (fMRI) (rs-fMRI) and task-based meta-analytic connectivity modeling (MACM).
METHODS: We report the clinical and stimulation characteristics of three patients with left hemispheric language dominance who demonstrate forced thought with functional mapping. To examine the brain networks underlying this phenomenon, we used the regions of interest (ROI) centered at the active electrode pairs. We modeled functional networks using two approaches: (1) rs-fMRI functional connectivity analysis, representing 81 healthy controls and (2) meta-analytic connectivity modeling (MACM), representing 8260 healthy subjects. We also determined the overlapping regions between these three subjects' rs-fMRI and MACM networks through a conjunction analysis.
RESULTS: We identified that left PFC was associated with a large-scale functional network including frontal, temporal, and parietal regions, a network that has been associated with multiple cognitive functions including semantics, speech, attention, working memory, and explicit memory.
CONCLUSIONS: We illustrate the neural networks involved in conceptual thought through a unique patient population and argue that PFC supports this function through activation of a widespread network.

PMID: 31951969 [PubMed - as supplied by publisher]

Fetal Response to a Maternal Internal Auditory Stimulus.

Sat, 01/18/2020 - 19:52

Fetal Response to a Maternal Internal Auditory Stimulus.

J Magn Reson Imaging. 2020 Jan 17;:

Authors: Goldberg E, McKenzie CA, de Vrijer B, Eagleson R, de Ribaupierre S

Abstract
BACKGROUND: Functional MRI (fMRI) is a noninvasive method to investigate the neural correlates of brain development. Insight into the rapidly developing brain in utero is limited, and fetal fMRI can be used to gain a greater understanding of the developmental process. Fetal brain fMRI is typically limited to resting-state fMRI due to the difficulty to instruct or provide a stimulus to the fetus. Previous studies have employed auditory task fMRI with an external sound stimulus directly on the abdomen of the mother; however, this practice has since been deemed unsafe for the developing fetus.
PURPOSE: To investigate a reliable and safe paradigm to study the development of fetal brain networks, we postulated that an internal task, such as the mother's singing, as the auditory stimulus would result in activation in the fetal primary auditory cortex.
STUDY TYPE: Cohort.
POPULATION: Pregnant women with singleton pregnancies (n = 9; 33-38 weeks gestational age).
FIELD STRENGTH/SEQUENCE: All subjects underwent two task-based block design blood oxygen level-dependent (BOLD) at 1.5T or 3T.
ASSESSMENT: Each volume was assessed for fetal motion and manually reoriented and realigned to correct for fetal motion. Once the motion was corrected, a gestational age-matched parcellated atlas with regions of interest overlaid onto the activation map was used to determine which regions in the brain had activation during task phases.
STATISTICAL TESTS: First Level Analysis. MRI data were analyzed using SPM 12 as a task fMRI.
RESULTS: Eight subjects had activation on the right Heschl's gyrus; six fetuses demonstrated activation on the left when exposed to the internal acoustic stimulus. Additionally, activation was found on the right and left middle cingulate cortex (MCC) and the left putamen.
DATA CONCLUSION: Maternal singing can be used as an internal stimulus to activate the auditory network and Heschl's gyrus during fetal fMRI.
LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY STAGE: 2.

PMID: 31951084 [PubMed - as supplied by publisher]

Potential for Resting-State fMRI of the Amygdala in Elucidating Neurological Mechanisms of Adaptive Self-Regulatory Strategies: A Systematic Review.

Sat, 01/18/2020 - 19:52

Potential for Resting-State fMRI of the Amygdala in Elucidating Neurological Mechanisms of Adaptive Self-Regulatory Strategies: A Systematic Review.

Brain Connect. 2020 Jan 17;:

Authors: Warren SM, Chou YH, Steklis HD

Abstract
Evolutionary-developmental theories consider the evolved mechanisms underlying adaptive behavioral strategies shaped in response to early environmental cues. Identifying neurological mechanisms mediating processes of conditional adaptation in humans is an active area of research. Resting-state functional magnetic resonance imaging (RS-fMRI) captures functional connectivity theorized to represent the underlying functional architecture of the brain. This allows for investigating how underlying functional brain connections are related to early experiences during development, as well as current traits and behaviors. This review explores the potential of RS-fMRI of the amygdala for advancing research on the neurological mechanisms underlying adaptive strategies developed in early adverse environments. RS-fMRI studies of early life stress and amygdala functional connectivity within the frame of evolutionary theories are reviewed, specifically regarding the development of self-regulatory strategies. The potential of RS-fMRI for investigating the effects of early life stress on developmental trajectories of self-regulation is discussed.

PMID: 31950847 [PubMed - as supplied by publisher]

Sleep/Wake Regularity Associated with Default Mode Network Structure among Healthy Adolescents and Young Adults.

Sat, 01/18/2020 - 19:52
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Sleep/Wake Regularity Associated with Default Mode Network Structure among Healthy Adolescents and Young Adults.

Sci Rep. 2020 Jan 16;10(1):509

Authors: Lunsford-Avery JR, Damme KSF, Engelhard MM, Kollins SH, Mittal VA

Abstract
Sleep deprivation and disorders are linked to reduced DMN connectivity. Less is known about how naturalistic sleep patterns - specifically sleep irregularity - relate to the DMN, particularly among adolescents and young adults. Additionally, no studies have utilized graph theory analysis to clarify whether sleep-related decreases in connectivity reflect global or local DMN changes. Twenty-five healthy adolescents and young adults (age range = 12-22; mean = 18.08; SD = 2.64, 56% female) completed 7 days of actigraphy and resting-state fMRI. Sleep regularity was captured by the Sleep Regularity Index (SRI) and the relationship between the SRI and DMN was examined using graph theory analysis. Analogous analyses explored relationships between the SRI and additional resting-state networks. Greater sleep regularity related to decreased path length (increased network connectivity) in DMN regions, particularly the right and left lateral parietal lobule, and the Language Network, including the left inferior frontal gyrus and the left posterior superior frontal gyrus. Findings were robust to covariates including sex and age. Sleep and DMN function may be tightly linked during adolescence and young adulthood, and reduced DMN connectivity may reflect local changes within the network. Future studies should assess how this relationship impacts cognitive development and neuropsychiatric outcomes in this age group.

PMID: 31949189 [PubMed - in process]

Effect of connectivity measures on the identification of brain functional core network at rest.

Sat, 01/18/2020 - 19:52
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Effect of connectivity measures on the identification of brain functional core network at rest.

Conf Proc IEEE Eng Med Biol Soc. 2019 Jul;2019:6426-6429

Authors: Rizkallah J, Amoud H, Wendling F, Hassan M

Abstract
Magneto/Electro-encephalography (M/EEG) source connectivity is an emergent tool to identify brain networks with high time/space resolution. Here, we aim to identify the brain core network (s-core decomposition) using dense-EEG. We also evaluate the effect of the functional connectivity methods used and more precisely the effect of the correction for the so-called source leakage problem. Two connectivity measures were evaluated: the phase locking value (PLV) and phase lag index (PLI) that supposed to deal with the leakage problem by removing the zero-lag connections. Both methods were evaluated on resting state dense-EEG signals recorded from 19 healthy participants. Core networks obtained by each method was compared to those computed using fMRI from 487 healthy participants at rest (from the Human Connectome Project - HCP). The correlation between networks obtained by EEG and fMRI was used as performance criterion. Results show that PLV networks are closer to fMRI networks with significantly higher correlation values with fMRI networks, than PLI networks. Results suggest caution when selecting the functional connectivity methods and mainly methods that remove the zero-lag connections as it can severely affect the network characteristics. The choice of functional connectivity measure is indeed crucial not only in cognitive neuroscience but also in clinical neuroscience.

PMID: 31947313 [PubMed - in process]

Disruption of brain network organization in primary open angle glaucoma.

Sat, 01/18/2020 - 19:52
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Disruption of brain network organization in primary open angle glaucoma.

Conf Proc IEEE Eng Med Biol Soc. 2019 Jul;2019:4338-4341

Authors: Minosse S, Floris R, Nucci C, Toschi N, Garaci F, Martucci A, Lanzafame S, Di Giuliano F, Picchi E, Cesareo M, Mancino R, Guerrisi M

Abstract
Resting-state functional magnetic resonance imaging (rs-fMRI) is commonly employed to study changes in functional brain connectivity. Recently, the hypothesis of a brain involvement in primary open angle glaucoma has sprung interest for neuroimaging studies in this pathology. The purpose of this study is to evaluate a putative reorganization of brain networks in glaucomatous patients through graph-theoretical measures of integration, segregation and centrality by exploiting a multivariate networks association measure and a recently introduced global and local brain network disruption index. Nineteen glaucoma patients and sixteen healthy control subjects (age: 50 - 76, mean 61 years) underwent rs-fMRI examination at 3T. After preprocessing, rs-fMRI time series were parcellated into 116 regions (AAL atlas), adjacency matrices were computed based on partial correlations and graph-theoretical measures of integration, segregation and centrality as well as group-wise and subject-wise disruption index estimates were generated for all subjects. We found that the group-wise disruption index was negative and statistically different from 0 in for all graph theoretical metrics. Additionally, statistically significant group-wise differences in subject-wise disruption indexes were found in all local metrics. The differences in local network measures highlight cerebral reorganization of brain networks in glaucoma patients, supporting the interpretation of glaucoma as central nervous system disease, likely part of the heterogeneous group of recently described disconnection syndromes.

PMID: 31946828 [PubMed - in process]

Resting-State Functional Connectivity in Popular Targets for Deep Brain Stimulation in the Treatment of Major Depression: An Application of a Graph Theory.

Sat, 01/18/2020 - 19:52
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Resting-State Functional Connectivity in Popular Targets for Deep Brain Stimulation in the Treatment of Major Depression: An Application of a Graph Theory.

Conf Proc IEEE Eng Med Biol Soc. 2019 Jul;2019:4334-4337

Authors: Amiri S, Arbabi M, Kazemi K, Parvaresh-Rizi M, Mirbagheri MM

Abstract
We examined the functional connectivity of subcallosal cingulate gyrus (SCG), nucleus accumbens (NAc), and ventral caudate (VCa), the main target areas for the treatment of major depression disorder (MDD), using deep brain stimulation (DBS). MDD is one of the most common diseases in the world, and approximately 30% of MDD patients do not respond to common therapies, including psychotherapy and antidepressant medications. Alternatively, DBS has been recently used to treat MDD. Resting state fMRI was obtained from seventeen healthy subjects and seven MDD patients. The functional connectivity network of the brain was constructed for all subjects and measured by the `degree' value for each SCG, NAc, and VCa regions using the graph theory analysis. The results show that the degree values of VCa and the left SCG are higher in the MDD group than the healthy group. Furthermore, the patterns of the degree values were different for the right and left hemispheres in MDD patients. Our findings suggest that degree values and their patterns have a potential to be used as diagnosis tools to detect the brain areas with abnormal functional connectivity.

PMID: 31946827 [PubMed - in process]

Resting State Neural Correlates of Cardiac Sympathetic Dynamics in Healthy Subjects.

Sat, 01/18/2020 - 19:52
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Resting State Neural Correlates of Cardiac Sympathetic Dynamics in Healthy Subjects.

Conf Proc IEEE Eng Med Biol Soc. 2019 Jul;2019:4330-4333

Authors: Valenza G, Duggento A, Passamonti L, Toschi N, Barbieri R

Abstract
Recent advances in functional Magnetic Resonance Imaging (fMRI) research have uncovered the existence of the central autonomic network (CAN), which comprises brain regions whose activity correlates with autonomic nervous system dynamics. By exploiting the spectral paradigm of heartbeat dynamics, cortical and sub-cortical areas functionally linked to vagal activity have been identified. However, due to methodological limitations, functional neural correlates of cardiac sympathetic dynamics remain uncharacterized. To this extent, we exploit the high spatiotemporal resolution of fMRI data from the Human Connectome Project to study the CAN activity by correlating a recently proposed instantaneous characterization of sympathetic activity (the sympathetic activity index - SAI) from heartbeat dynamics. SAI estimates are embedded into the probabilistic modeling of inhomogeneous point-processes, and are derived from a combination of disentangling coefficients linked to the orthonormal Laguerre functions. By analyzing resting state recordings from 34 young healthy people, we obtain positive correlations between instantaneous SAI estimates and a number of brain regions including frontal pole, insular cortex, frontal and temporal gyri, lateral occipital cortex, paracingulate and cingulate gyri, precuneus and temporal fusiform cortices, as well as thalamus, caudate nucleus, putamen, brain-stem, hippocampus, amygdala, and nucleus accumbens. Our findings significantly extend current knowledge on the CAN, opening new avenues in the characterization of healthy and pathological states in humans.

PMID: 31946826 [PubMed - in process]

Predicting Male vs. Female from Task-fMRI Brain Connectivity.

Sat, 01/18/2020 - 19:52
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Predicting Male vs. Female from Task-fMRI Brain Connectivity.

Conf Proc IEEE Eng Med Biol Soc. 2019 Jul;2019:4089-4092

Authors: Sen B, Parhi KK

Abstract
A number of behavioral and cognitive functions of brain differ between male and female. Occurrences of psychiatric disorders, e.g., attention deficit hyperactivity disorder, autism, depression and schizophrenia also vary from male to female. Understanding the unique cognitive expressions in gender-specific brain functions may lead to insights into the risks and associated responses for a certain external simulation or medications. Previously resting-state functional magnetic resonance imaging (r-fMRI) has been used extensively to understand gender differences using functional network connectivity analysis. However, how the brain functional network changes during a cognitive task for different genders is relatively unknown. This paper makes use of a large data set to test whether task-fMRI functional connectivity can be utilized to predict male vs. female. In addition, it also identifies functional connectivity features that are most predictive of gender. The cognitive task-fMRI data consisting 475 healthy controls is taken from the Human Connectome Project (HCP) database. Pearson correlation coefficients are extracted using mean time-series from anatomical brain regions. Partial least squares (PLS) regression with feature selection on the correlation coefficients achieves a classification accuracy of 0.88 for classifying male vs. female using emotion task data. In addition it is found that inter hemispheric connectivity is most important for predicting gender from task-fMRI.

PMID: 31946770 [PubMed - in process]