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Segregation of salience network predicts treatment response of depression to repetitive transcranial magnetic stimulation.

9 hours 24 min ago
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Segregation of salience network predicts treatment response of depression to repetitive transcranial magnetic stimulation.

Neuroimage Clin. 2019 Feb 13;22:101719

Authors: Fan J, Tso IF, Maixner DF, Abagis T, Hernandez-Garcia L, Taylor SF

Abstract
BACKGROUND: The present study tested the hypothesis that network segregation, a graph theoretic measure of functional organization of the brain, is correlated with treatment response in patients with major depressive disorder (MDD) undergoing repetitive transcranial magnetic stimulation (rTMS).
METHODS: Network segregation, calculated from resting state functional magnetic resonance imaging scans, was measured in 32 patients with MDD who entered a sham-controlled, double-blinded, randomized trial of rTMS to the left dorsolateral prefrontal cortex, and a cohort of 20 healthy controls (HCs). Half of the MDD patients received sham treatment in the blinded phase, followed by active rTMS in the open-label phase. The analyses focused on segregation of the following networks: default mode (DMN), salience (SN), fronto-parietal (FPN), cingulo-opercular (CON), and memory retrieval (MRN).
RESULTS: There was no differential change in network segregation comparing sham to active treatment. However, in the combined group of patients who completed active rTMS treatment (in the blinded plus open-label phases), higher baseline segregation of SN significantly predicted more symptom improvement after rTMS. Compared to HCs at baseline, MDD patients showed decreased segregation in DMN, and trend-level decreases in SN and MRN.
CONCLUSION: The results highlight the importance of network segregation in MDD, particularly in the SN, where more normal baseline segregation of SN may predict better treatment response to rTMS in depression.

PMID: 30776777 [PubMed - as supplied by publisher]

Investigation of Resting-State BOLD Networks in the Human Brainstem and Spinal Cord.

9 hours 24 min ago
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Investigation of Resting-State BOLD Networks in the Human Brainstem and Spinal Cord.

Neuroscience. 2019 Feb 15;:

Authors: Harita S, Ioachim G, Powers J, Stroman PW

Abstract
Resting-state functional magnetic resonance imaging (rs-fMRI) has been used to investigate networks within the cortex and has also provided some insight into the networks present in the brainstem (BS) and spinal cord (SC). The purpose of this study was to investigate resting-state blood oxygenation-level dependent (BOLD) fluctuations in the BS/SC and to identify resting-state networks (RSNs) across these regions. Resting-state BOLD fMRI data were obtained from the entire BS and cervical SC in 16 healthy participants, at 3 T, with T2-weighted single-shot fast spin-echo imaging. Data were spatially normalized and processed to remove physiological noise. Cluster-cluster functional connectivity was investigated across the entire 3D region by means of temporal correlations, and structural equation modeling (SEM) was used to investigate RSNs. Extensive connectivity was observed within and across BS and SC regions, with connections spanning up to 120 mm, although shorter connections were more prevalent. SEM results revealed extensive brainstem-cord connectivity that included specific anatomical regions within the brainstem. The results indicate the presence of a complex resting-state network which is highly interconnected in the spinal cord. Known anatomical connections between cortical and BS regions support the conclusion that the observed resting-state BOLD fluctuations in the BS/SC may be related to autonomic regulation. Future studies are required to further investigate these resting-state BOLD networks.

PMID: 30776404 [PubMed - as supplied by publisher]

Atypical Flexibility in Dynamic Functional Connectivity Quantifies the Severity in Autism Spectrum Disorder.

9 hours 24 min ago
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Atypical Flexibility in Dynamic Functional Connectivity Quantifies the Severity in Autism Spectrum Disorder.

Front Hum Neurosci. 2019;13:6

Authors: Harlalka V, Bapi RS, Vinod PK, Roy D

Abstract
Resting-state functional connectivity (FC) analyses have shown atypical connectivity in autism spectrum disorder (ASD) as compared to typically developing (TD). However, this view emerges from investigating static FC overlooking the whole brain transient connectivity patterns. In our study, we investigated how age and disease influence the dynamic changes in functional connectivity of TD and ASD. We used resting-state functional magnetic resonance imaging (rs-fMRI) data stratified into three cohorts: children (7-11 years), adolescents (12-17 years), and adults (18+ years) for the analysis. The dynamic variability in the connection strength and the modular organization in terms of measures such as flexiblity, cohesion strength, and disjointness were explored for each subject to characterize the differences between ASD and TD. In ASD, we observed significantly higher inter-subject dynamic variability in connection strength as compared to TD. This hyper-variability relates to the symptom severity in ASD. We also found that whole-brain flexibility correlates with static modularity only in TD. Further, we observed a core-periphery organization in the resting-state, with Sensorimotor and Visual regions in the rigid core; and DMN and attention areas in the flexible periphery. TD also develops a more cohesive organization of sensorimotor areas. However, in ASD we found a strong positive correlation of symptom severity with flexibility of rigid areas and with disjointness of sensorimotor areas. The regions of the brain showing high predictive power of symptom severity were distributed across the cortex, with stronger bearings in the frontal, motor, and occipital cortices. Our study demonstrates that the dynamic framework best characterizes the variability in ASD.

PMID: 30774589 [PubMed]

Low and high frequency rTMS effects on resting-state functional connectivity between the postcentral gyrus and the insula.

9 hours 24 min ago
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Low and high frequency rTMS effects on resting-state functional connectivity between the postcentral gyrus and the insula.

Brain Connect. 2019 Feb 16;:

Authors: Addicott M, Luber B, Nguyen D, Palmer H, Lisanby S, Appelbaum L

Abstract
The insular cortex supports the conscious awareness of physical and emotional sensations, and the ability to modulate the insula could have important clinical applications in psychiatry. Repetitive transcranial magnetic stimulation (rTMS) uses transient magnetic fields to induce electrical currents in the superficial cortex. Given its deep location in the brain, the insula may not be directly stimulated by rTMS; however, rTMS may modulate the insula via its functional connections with superficial cortical regions. Furthermore, low versus high frequency rTMS are thought to have opposing effects on cortical excitability, and the present study investigated these effects on brain activity and functional connectivity with the insula. Separate groups of healthy participants (n = 14 per group) received low (1 Hz) or high (10 Hz) frequency rTMS in 5 daily sessions to the right postcentral gyrus, a superficial region known to be functionally connected to the insula. Resting-state functional connectivity (RSFC) was measured pre- and post-rTMS. Both 1 Hz and 10 Hz rTMS increased RSFC between the right postcentral gyrus and the left insula. These results suggest that low and high frequency rTMS have similar long-term effects on brain activity and RSFC. However, given the lack of difference, we cannot exclude the possibility that these effects are simply due to a non-specific effect. Given this limitation, these unexpected results underscore the need for acoustic- and stimulation-matched sham control conditions in rTMS research.

PMID: 30773890 [PubMed - as supplied by publisher]

[Brain regions responding to acupuncture stimulation of Zusanli (ST36) in healthy subjects analyzed on the basis of spontaneous brain activity].

9 hours 24 min ago
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[Brain regions responding to acupuncture stimulation of Zusanli (ST36) in healthy subjects analyzed on the basis of spontaneous brain activity].

Zhen Ci Yan Jiu. 2019 Jan 25;44(1):66-70

Authors: Xiang AF, Liu H, Liu S, Shen XY

Abstract
OBJECTIVE: To determine the attributes of responses of the higher nerve center to acupuncture stimulation of Zusanli (ST36) on the basis of spontaneous brain activity, so as to explore the synchronization level of different brain rejoins after acupuncture.
METHODS: All studies using fMRI to investigate the effect of acupuncture stimulation of ST36 and/or other acupoints on the human brain (at least 10 healthy subjects or patients in one group) published in journals from January of 1995 to January of 2018 were searched from databases of CNKI and PubMed by using keywords of acupuncture, electroacupuncture, and resting-state functional magnetic resonance images (rs-fMRI) or regional homogeneity (ReHo). Brain functional image data of acupuncture stimulation of ST36 and/or other acupoints were collected and analyzed with anisotropic effect size-signed differential mapping (AES-SDM) software (Meta-analysis), and those of acupuncture of simple ST36 analyzed as a subgroup.
RESULTS: A total of 229 papers in Chinese and 109 in English were collected. According to our inclusive and exclusive standards, 11 papers containing 235 subjects were brought into analysis at last. Meta-analysis of brain image data of acupuncture at ST36 and/or other acupoints (comparison between pre- and post-acupuncture) revealed that the same brain regions (generality) which showed a significant increase in ReHo, are the right and left anterior cingulated gyrus, right caudate, left superior frontal gyrus, right middle frontal gyrus, and the right paracentral lobe, and those which showed a marked decrease of ReHo are the left mid-inferior occipital gyrus, left and right precentral and postcentral gyrus. The brain regions responding to acupuncture at ST36 only (specificity) are the right inferior parietal lobe, left middle inferior gyrus, right posterior lobe of cerebellum, and the left angular gyrus which displayed an increase of ReHo, and the right middle superior frontal gyrus which showed a decrease in ReHo.
CONCLUSION: After acupuncturing at ST36, the relative generality and specificity of the central response in healthy subjects reflected as the location of the affected brain regions and the difference in the synchronization level of the corresponding spontaneous brain activities.

PMID: 30773866 [PubMed - in process]

Altered dynamic global signal topography in antipsychotic-naive adolescents with early-onset schizophrenia.

Tue, 02/19/2019 - 12:22

Altered dynamic global signal topography in antipsychotic-naive adolescents with early-onset schizophrenia.

Schizophr Res. 2019 Feb 14;:

Authors: Wang X, Liao W, Han S, Li J, Zhang Y, Zhao J, Chen H

Abstract
Schizophrenia (SCZ) is a severe neuropsychiatric disease associated with dysfunction of brain regions and networks. Recent, functional magnetic resonance imaging (fMRI) studies have determined that the global signal (GS) is an important source of the local neuronal activity. However, the dynamics of this effect in SCZ remains unknown. To address this issue, 39 drug-naive patients with early-onset schizophrenia (EOS) and 31 age-, gender- and education-matched healthy controls underwent resting-state fMRI scans. Dynamic functional connectivity (DFC) was employed to assess the dynamic patterns of the GS in EOS. Dynamic analysis demonstrated that the topography of the GS in EOS can be divided into five different states. In the state1, the GS mainly affected the sensory regions. In the state2, the GS mainly affected the default mode network (DMN). In the state3, the GS mainly affected the frontoparietal network and the cingulate-opercular network. In the state4, the GS mainly affected the sensory and subcortical regions. In the state5, the GS mainly affected the sensory regions and DMN. In particular, the changes in the cerebellum, putamen and supramarginal gyrus was inversely proportional to the clinical symptoms. Our findings demonstrate that the influence of the GS on brain networks is dynamic and changes of this relationship may associate with clinical behavior in SCZ.

PMID: 30772067 [PubMed - as supplied by publisher]

Impaired prefrontal cortex-thalamus pathway in intractable temporal lobe epilepsy with aberrant executive control function: MRI evidence.

Mon, 02/18/2019 - 00:20
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Impaired prefrontal cortex-thalamus pathway in intractable temporal lobe epilepsy with aberrant executive control function: MRI evidence.

Clin Neurophysiol. 2019 Jan 18;130(4):484-490

Authors: Zhang C, Zhang H, Xu K, Yang H, Liu C, Yu T, Chen N, Li K

Abstract
OBJECTIVES: This study aimed to assess structural and functional connectivity alterations of the prefrontal cortex (PFC)-thalamus axis in individuals with unilateral intractable temporal lobe epilepsy (TLE) showing executive control function (ECF) impairment and to explore the potential mechanism.
METHODS: Thirty-eight individuals with intractable left TLE and twenty-nine healthy controls (HCs) were recruited for diffusion tensor imaging (DTI) and resting-state fMRI (rs-fMRI) scanning. According to the ECF state, patients were assigned to normal and impaired ECF groups. Functional connectivity (FC) and probabilistic diffusion tractography of the PFC- thalamus pathway were assessed. The general linear model (GLM) was employed for comparing fiber number (FN) and FC between groups. Pearson correlation analysis of FC, FN and ECF test scores was performed.
RESULTS: FC and FN of left DLPFC-thalamus pathway were significantly increased in the impaired ECF group compared with the normal ECF and HC groups. However, FC and FN were not correlated with ECF score.
CONCLUSIONS: These findings indicated increased connectivity between DLPFC and the ipsilateral thalamus might reflect nonfunctional nerve remodeling along the seizure pathway.
SIGNIFICANCE: The present findings suggest that the DLPFC-thalamus pathway may be an important structure for exploring the mechanisms of TLE with ECF dysfunction.

PMID: 30771725 [PubMed - as supplied by publisher]

Effects of Motor Imagery and Visual Neurofeedback on Activation in the Swallowing Network: A Real-Time fMRI Study.

Mon, 02/18/2019 - 00:20
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Effects of Motor Imagery and Visual Neurofeedback on Activation in the Swallowing Network: A Real-Time fMRI Study.

Dysphagia. 2019 Feb 15;:

Authors: Kober SE, Grössinger D, Wood G

Abstract
Motor imagery of movements is used as mental strategy in neurofeedback applications to gain voluntary control over activity in motor areas of the brain. In the present functional magnetic resonance imaging (fMRI) study, we first addressed the question whether motor imagery and execution of swallowing activate comparable brain areas, which has been already proven for hand and foot movements. Prior near-infrared spectroscopy (NIRS) studies provide evidence that this is the case in the outer layer of the cortex. With the present fMRI study, we want to expand these prior NIRS findings to the whole brain. Second, we used motor imagery of swallowing as mental strategy during visual neurofeedback to investigate whether one can learn to modulate voluntarily activity in brain regions, which are associated with active swallowing, using real-time fMRI. Eleven healthy adults performed one offline session, in which they executed swallowing movements and imagined swallowing on command during fMRI scanning. Based on this functional localizer task, we identified brain areas active during both tasks and defined individually regions for feedback. During the second session, participants performed two real-time fMRI neurofeedback runs (each run comprised 10 motor imagery trials), in which they should increase voluntarily the activity in the left precentral gyrus by means of motor imagery of swallowing while receiving visual feedback (the visual feedback depicted one's own fMRI signal changes in real-time). Motor execution and imagery of swallowing activated a comparable network of brain areas including the bilateral pre- and postcentral gyrus, inferior frontal gyrus, basal ganglia, insula, SMA, and the cerebellum compared to a resting condition. During neurofeedback training, participants were able to increase the activity in the feedback region (left lateral precentral gyrus) but also in other brain regions, which are generally active during swallowing, compared to the motor imagery offline task. Our results indicate that motor imagery of swallowing is an adequate mental strategy to activate the swallowing network of the whole brain, which might be useful for future treatments of swallowing disorders.

PMID: 30771088 [PubMed - as supplied by publisher]

Ultra-high field MRI reveals mood-related circuit disturbances in depression: a comparison between 3-Tesla and 7-Tesla.

Mon, 02/18/2019 - 00:20
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Ultra-high field MRI reveals mood-related circuit disturbances in depression: a comparison between 3-Tesla and 7-Tesla.

Transl Psychiatry. 2019 Feb 15;9(1):94

Authors: Morris LS, Kundu P, Costi S, Collins A, Schneider M, Verma G, Balchandani P, Murrough JW

Abstract
Ultra-high field 7-Tesla (7 T) MRI has the potential to advance our understanding of neuropsychiatric disorders, including major depressive disorder (MDD). To date, few studies have quantified the advantage of resting state functional MRI (fMRI) at 7 T compared to 3-Tesla (3 T). We conducted a series of experiments that demonstrate the improvement in temporal signal-to-noise ratio (TSNR) of a multi-echo multi-band fMRI protocol with ultra-high field 7 T MRI, compared to a similar protocol using 3 T MRI in healthy controls (HC). We also directly tested the enhancement in ultra-high field 7 T fMRI signal power by examining the ventral tegmental area (VTA), a small midbrain structure that is critical to the expected neuropathology of MDD but difficult to discern with standard 3 T MRI. We demonstrate up to 300% improvement in TSNR and resting state functional connectivity coefficients provided by ultra-high field 7 T fMRI compared to 3 T, indicating enhanced power for detection of functional neural architecture. A multi-echo based acquisition protocol and signal denoising pipeline afforded greater gain in signal power compared to classic acquisition and denoising pipelines. Furthermore, ultra-high field fMRI revealed mood-related neurocircuit disturbances in patients with MDD compared to HC, which were not detectable with 3 T fMRI. Ultra-high field 7 T fMRI may provide an effective tool for studying functional neural architecture relevant to MDD and other neuropsychiatric disorders.

PMID: 30770788 [PubMed - in process]

Integration and segregation of functional segmented anterior and posterior hippocampal networks in memory performance.

Sun, 02/17/2019 - 00:19
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Integration and segregation of functional segmented anterior and posterior hippocampal networks in memory performance.

Behav Brain Res. 2019 Feb 12;:

Authors: Xu J, Zhang M

Abstract
PURPOSE: To determine the association between functional connectivity (FC) of functional-segmented anterior and posterior portions of the hippocampus and performance on verbal and visual memory tests in a young, healthy population.
METHODS: We recruited 100 healthy participants in the age of 19-29. Resting state fMRI data were acquired and voxel-wise correlation analysis was performed to functionally divide the hippocampus. We investigated the inter-hemispheric hippocampal-cortical functional connectivity after the participants took the assessment of episodic memory using verbal (California Verbal Learning Test II, CVLT-II) and visual subtests (Rey-Osterrieth Complex Figure, ROCF). The partial correlations were used to identify the association between the intra-hemispheric hippocampal-cortical mean resting correlation and memory performance.
RESULTS: The results showed that the anterior and posterior hippocampal networks involved differently in verbal and visual memory. Intra-hemispheric FC between left posterior hippocampus and posterior parahippocampal gyrus (PPHG) was positively correlated with CVLT-II Trail 2 Immediate Free Recall (r = 0.223, p = 0.029). Intra-hemispheric FC between left posterior hippocampus and posterior cingulate (PCC) was negatively correlated with ROCF Immediate Recall (r=-0.217 p = 0.034). Intra-hemispheric FC between left anterior hippocampus and temporal pole (TP) negatively correlated with ROCF Delayed Recall (r=-0.228, p = 0.025). Split half resampling procedure results showed some repeatability in our subjects.
CONCLUSION: The present results demonstrated that, the anterior hippocampus was specifically involved in the visual memory processing, whereas the posterior hippocampus contributed to both the verbal and visual memories, which may have implications for a functionally synergetic and dissociable role of the hippocampus in different kinds of memory.

PMID: 30768997 [PubMed - as supplied by publisher]

Sertraline Effects on Striatal Resting-State Functional Connectivity in Youth With OCD: A Pilot Study.

Sun, 02/17/2019 - 00:19
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Sertraline Effects on Striatal Resting-State Functional Connectivity in Youth With OCD: A Pilot Study.

J Am Acad Child Adolesc Psychiatry. 2018 Oct 30;:

Authors: Bernstein GA, Cullen KR, Harris EC, Conelea CA, Zagoloff AD, Carstedt PA, Lee SS, Mueller BA

Abstract
OBJECTIVE: Foundational knowledge on neural circuitry underlying pediatric obsessive-compulsive disorder (OCD) and how it changes during standard treatment is needed to provide the basis for conceptualization and development of novel, targeted treatments. This study explored the effects of sertraline, a selective serotonin reuptake inhibitor, on resting-state functional connectivity (RSFC) in cortico-striatal-thalamic-cortical circuits in pediatric OCD.
METHOD: Medication-free youths with OCD (n=14) and healthy controls (n=14) were examined at baseline and 12 weeks with resting-state fMRI. Between scan sessions, participants with OCD received 12 weeks of sertraline. For each scan, we conducted seed-based whole-brain RSFC analyses with 6 striatal seeds. Analysis of variance (ANOVA) examined the interaction between group and time on striatal connectivity, including cluster-based thresholding to correct for multiple tests. Connectivity changes within circuits identified in group analyses were correlated with clinical change.
RESULTS: Two significant group x time effects in the OCD group showed increased striatal connectivity from baseline to 12 weeks compared with controls. Circuits demonstrating this pattern included right putamen with left frontal cortex/insula and left putamen with left frontal cortex and pre- and post-central cortices. Increase in connectivity in left putamen circuit was significantly correlated with clinical improvement on Children's Yale-Brown Obsessive-Compulsive Scale (r = -0.58, p = .03).
CONCLUSION: Sertraline appears to affect specific striatal-based circuits in pediatric OCD, and in part, these changes may account for clinical improvement. Future work is needed to confirm these preliminary findings, which would facilitate identification of circuit-based targets for novel treatment development.

PMID: 30768407 [PubMed - as supplied by publisher]

Association Between Age and Familial Risk for Alcoholism on Functional Connectivity in Adolescence.

Sun, 02/17/2019 - 00:19
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Association Between Age and Familial Risk for Alcoholism on Functional Connectivity in Adolescence.

J Am Acad Child Adolesc Psychiatry. 2019 Feb 13;:

Authors: Vaidya JG, Elmore AL, Wallace A, Langbehn DR, Kramer JR, Kuperman S, O'Leary DS

Abstract
OBJECTIVE: Youth with a family history of alcohol use disorder (family history positive; FHP) are at increased risk for developing maladaptive substance use relative to family history negative (FHN) peers. Building on earlier studies demonstrating morphological differences and distinct patterns of neural activation in FHP, the purpose of the present study was to investigate differential intrinsic functional connectivity among brain networks indexing premorbid risk of developing alcohol use disorder (AUD).
METHOD: The current study examined intrinsic functional connectivity using resting state functional magnetic resonance imaging (fMRI) in 191 adolescents 13 to 18 years with and without family history of alcohol use disorder (AUD) via independent component analysis (ICA), a method enabling data-driven investigation of internetwork and intranetwork connectivity among brain regions at rest.
RESULTS: Analyses revealed significantly lower intranetwork connectivity in FHP compared to FHN participants between dorsal premotor cortex and other sensorimotor network regions. Reduced intranetwork connectivity in this region was further correlated with the number of biological family members with AUD and mood disorders. Robust differences were also evident in internetwork connectivity as a function of age. However, there was no evidence for family history by age interactions.
CONCLUSION: Intra- but not inter-network connectivity appears to differentiate FHP and FHN adolescents whereas age differences within adolescence are marked by differences in internetwork connectivity.

PMID: 30768382 [PubMed - as supplied by publisher]

Manipulation of Subcortical and Deep Cortical Activity in the Primate Brain Using Transcranial Focused Ultrasound Stimulation.

Sun, 02/17/2019 - 00:19
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Manipulation of Subcortical and Deep Cortical Activity in the Primate Brain Using Transcranial Focused Ultrasound Stimulation.

Neuron. 2019 Feb 07;:

Authors: Folloni D, Verhagen L, Mars RB, Fouragnan E, Constans C, Aubry JF, Rushworth MFS, Sallet J

Abstract
The causal role of an area within a neural network can be determined by interfering with its activity and measuring the impact. Many current reversible manipulation techniques have limitations preventing their application, particularly in deep areas of the primate brain. Here, we demonstrate that a focused transcranial ultrasound stimulation (TUS) protocol impacts activity even in deep brain areas: a subcortical brain structure, the amygdala (experiment 1), and a deep cortical region, the anterior cingulate cortex (ACC, experiment 2), in macaques. TUS neuromodulatory effects were measured by examining relationships between activity in each area and the rest of the brain using functional magnetic resonance imaging (fMRI). In control conditions without sonication, activity in a given area is related to activity in interconnected regions, but such relationships are reduced after sonication, specifically for the targeted areas. Dissociable and focal effects on neural activity could not be explained by auditory confounds.

PMID: 30765166 [PubMed - as supplied by publisher]

Circadian phenotype impacts the brain's resting state functional connectivity, attentional performance and sleepiness.

Sat, 02/16/2019 - 00:19
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Circadian phenotype impacts the brain's resting state functional connectivity, attentional performance and sleepiness.

Sleep. 2019 Feb 15;:

Authors: Facer-Childs ER, Campos BM, Middleton B, Skene DJ, Bagshaw AP

Abstract
INTRODUCTION: Functional connectivity (FC) of the human brain's intrinsically connected networks underpins cognitive functioning and disruptions of FC are associated with sleep and neurological disorders. However, there is limited research on the impact of circadian phenotype and time of day on FC.
STUDY OBJECTIVES: The aim of this study was to investigate resting state FC of the default mode network (DMN) in Early and Late circadian phenotypes over a socially constrained day.
METHODS: 38 healthy individuals (14 male, 22.7 ± 4.2 years) categorised as Early (n =16) or Late (n = 22) using the Munich ChronoType Questionnaire took part. Following a two week baseline of actigraphy coupled with saliva samples for melatonin and cortisol rhythms, participants underwent testing at 14.00 h, 20.00 h and 08.00 h the following morning. Testing consisted of resting state functional MRI, a structural T1 scan, attentional cognitive performance tasks and self-reported daytime sleepiness. Seed based FC analysis from the medial prefrontal and posterior cingulate cortices of the DMN was performed, compared between groups and linked with behavioural data.
RESULTS: Fundamental differences in the DMN were observed between Early and Late circadian phenotypes. Resting state FC of the DMN predicted individual differences in attention and subjective ratings of sleepiness.
CONCLUSION: Differences in FC of the DMN may underlie the compromised attentional performance and increased sleepiness commonly associated with Late types when they conform to a societally constrained day that does not match their intrinsic circadian phenotype.

PMID: 30763951 [PubMed - as supplied by publisher]

Resting State Functional Connectivity of Dorsal Raphe Nucleus and Ventral Tegmental Area in Medication-Free Young Adults With Major Depression.

Sat, 02/16/2019 - 00:19
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Resting State Functional Connectivity of Dorsal Raphe Nucleus and Ventral Tegmental Area in Medication-Free Young Adults With Major Depression.

Front Psychiatry. 2018;9:765

Authors: Anand A, Jones SE, Lowe M, Karne H, Koirala P

Abstract
Background: This study has, for the first time, investigated the dorsal raphe nucleus (DRN) and ventral tegmental area (VTA) resting state whole-brain functional connectivity in medication-free young adults with major depression (MDD), at baseline and in relationship to treatment response. Method: A total of 119 subjects: 78 MDD (24 ± 4 years.) and 41 Healthy Controls (HC) (24 ± 3 years) were included in the analysis. DRN and VTA ROIs anatomical templates were used to extract resting state fluctuations and used to derive whole-brain functional connectivity. Differences between MDD and HCs were examined, as well as the correlation of baseline Hamilton Depression and Anxiety scale scores to the baseline DRN and VTA connectivity. The relationship to treatment response was examined by investigating the correlation of the percentage decrease in depression and anxiety scale scores with baseline connectivity measures. Results: There was a significant decrease (p = 0.05; cluster-wise corrected) in DRN connectivity with the prefrontal and mid-cingulate cortex in the MDD group, compared with the HC group. DRN connectivity with temporal areas, including the hippocampus and amygdala, positively correlated with baseline depression scores (p = 0.05; cluster-wise corrected). VTA connectivity with the cuneus-occipital areas correlated with a change in depression scores (p = 0.05; cluster-wise corrected). Conclusion: Our results indicate the presence of DRN-prefrontal and DRN-cingulate cortex connectivity abnormalities in young medication-free depressed subjects when compared to HCs and that the severity of depressive symptoms correlates with DRN-amygdala/hippocampus connectivity. VTA connectivity with the parietal and occipital areas is related to antidepressant treatment associated with a decrease in depressive symptoms. Future studies need to be carried out in larger and different age group populations to confirm the findings of the study.

PMID: 30761028 [PubMed]

Improved state change estimation in dynamic functional connectivity using hidden semi-Markov models.

Thu, 02/14/2019 - 03:15
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Improved state change estimation in dynamic functional connectivity using hidden semi-Markov models.

Neuroimage. 2019 Feb 09;:

Authors: Shappell H, Caffo BS, Pekar JJ, Lindquist MA

Abstract
The study of functional brain networks has grown rapidly over the past decade. While most functional connectivity (FC) analyses estimate one static network structure for the entire length of the functional magnetic resonance imaging (fMRI) time series, recently there has been increased interest in studying time-varying changes in FC. Hidden Markov models (HMMs) have proven to be a useful modeling approach for discovering repeating graphs of interacting brain regions (brain states). However, a limitation lies in HMMs assuming that the sojourn time, the number of consecutive time points in a state, is geometrically distributed. This may encourage inaccurate estimation of the time spent in a state before switching to another state. We propose a hidden semi-Markov model (HSMM) approach for inferring time-varying brain networks from fMRI data, which explicitly models the sojourn distribution. Specifically, we propose using HSMMs to find each subject's most probable series of network states and the graphs associated with each state, while properly estimating and modeling the sojourn distribution for each state. We perform a simulation study, as well as an analysis on both task-based fMRI data from an anxiety-inducing experiment and resting-state fMRI data from the Human Connectome Project. Our results demonstrate the importance of model choice when estimating sojourn times and reveal their potential for understanding healthy and diseased brain mechanisms.

PMID: 30753927 [PubMed - as supplied by publisher]

A mind-brain-body dataset of MRI, EEG, cognition, emotion, and peripheral physiology in young and old adults.

Thu, 02/14/2019 - 03:15
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A mind-brain-body dataset of MRI, EEG, cognition, emotion, and peripheral physiology in young and old adults.

Sci Data. 2019 Feb 12;6:180308

Authors: Babayan A, Erbey M, Kumral D, Reinelt JD, Reiter AMF, Röbbig J, Schaare HL, Uhlig M, Anwander A, Bazin PL, Horstmann A, Lampe L, Nikulin VV, Okon-Singer H, Preusser S, Pampel A, Rohr CS, Sacher J, Thöne-Otto A, Trapp S, Nierhaus T, Altmann D, Arelin K, Blöchl M, Bongartz E, Breig P, Cesnaite E, Chen S, Cozatl R, Czerwonatis S, Dambrauskaite G, Dreyer M, Enders J, Engelhardt M, Fischer MM, Forschack N, Golchert J, Golz L, Guran CA, Hedrich S, Hentschel N, Hoffmann DI, Huntenburg JM, Jost R, Kosatschek A, Kunzendorf S, Lammers H, Lauckner ME, Mahjoory K, Kanaan AS, Mendes N, Menger R, Morino E, Näthe K, Neubauer J, Noyan H, Oligschläger S, Panczyszyn-Trzewik P, Poehlchen D, Putzke N, Roski S, Schaller MC, Schieferbein A, Schlaak B, Schmidt R, Gorgolewski KJ, Schmidt HM, Schrimpf A, Stasch S, Voss M, Wiedemann A, Margulies DS, Gaebler M, Villringer A

Abstract
We present a publicly available dataset of 227 healthy participants comprising a young (N=153, 25.1±3.1 years, range 20-35 years, 45 female) and an elderly group (N=74, 67.6±4.7 years, range 59-77 years, 37 female) acquired cross-sectionally in Leipzig, Germany, between 2013 and 2015 to study mind-body-emotion interactions. During a two-day assessment, participants completed MRI at 3 Tesla (resting-state fMRI, quantitative T1 (MP2RAGE), T2-weighted, FLAIR, SWI/QSM, DWI) and a 62-channel EEG experiment at rest. During task-free resting-state fMRI, cardiovascular measures (blood pressure, heart rate, pulse, respiration) were continuously acquired. Anthropometrics, blood samples, and urine drug tests were obtained. Psychiatric symptoms were identified with Standardized Clinical Interview for DSM IV (SCID-I), Hamilton Depression Scale, and Borderline Symptoms List. Psychological assessment comprised 6 cognitive tests as well as 21 questionnaires related to emotional behavior, personality traits and tendencies, eating behavior, and addictive behavior. We provide information on study design, methods, and details of the data. This dataset is part of the larger MPI Leipzig Mind-Brain-Body database.

PMID: 30747911 [PubMed - in process]

Offline impact of transcranial focused ultrasound on cortical activation in primates.

Thu, 02/14/2019 - 03:15
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Offline impact of transcranial focused ultrasound on cortical activation in primates.

Elife. 2019 Feb 12;8:

Authors: Verhagen L, Gallea C, Folloni D, Constans C, Jensen DE, Ahnine H, Roumazeilles L, Santin M, Ahmed B, Lehericy S, Klein-Flügge MC, Krug K, Mars RB, Rushworth MF, Pouget P, Aubry JF, Sallet J

Abstract
To understand brain circuits it is necessary both to record and manipulate their activity. Transcranial ultrasound stimulation (TUS) is a promising non-invasive brain stimulation technique. To date, investigations report short-lived neuromodulatory effects, but to deliver on its full potential for research and therapy, ultrasound protocols are required that induce longer-lasting 'offline' changes. Here, we present a TUS protocol that modulates brain activation in macaques for more than one hour after 40 s of stimulation, while circumventing auditory confounds. Normally activity in brain areas reflects activity in interconnected regions but TUS caused stimulated areas to interact more selectively with the rest of the brain. In a within-subject design, we observe regionally specific TUS effects for two medial frontal brain regions - supplementary motor area and frontal polar cortex. Independently of these site-specific effects, TUS also induced signal changes in the meningeal compartment. TUS effects were temporary and not associated with microstructural changes.

PMID: 30747105 [PubMed - in process]

Hierarchical Heterogeneity across Human Cortex Shapes Large-Scale Neural Dynamics.

Thu, 02/14/2019 - 03:15
Related Articles

Hierarchical Heterogeneity across Human Cortex Shapes Large-Scale Neural Dynamics.

Neuron. 2019 Feb 05;:

Authors: Demirtaş M, Burt JB, Helmer M, Ji JL, Adkinson BD, Glasser MF, Van Essen DC, Sotiropoulos SN, Anticevic A, Murray JD

Abstract
The large-scale organization of dynamical neural activity across cortex emerges through long-range interactions among local circuits. We hypothesized that large-scale dynamics are also shaped by heterogeneity of intrinsic local properties across cortical areas. One key axis along which microcircuit properties are specialized relates to hierarchical levels of cortical organization. We developed a large-scale dynamical circuit model of human cortex that incorporates heterogeneity of local synaptic strengths, following a hierarchical axis inferred from magnetic resonance imaging (MRI)-derived T1- to T2-weighted (T1w/T2w) mapping and fit the model using multimodal neuroimaging data. We found that incorporating hierarchical heterogeneity substantially improves the model fit to functional MRI (fMRI)-measured resting-state functional connectivity and captures sensory-association organization of multiple fMRI features. The model predicts hierarchically organized higher-frequency spectral power, which we tested with resting-state magnetoencephalography. These findings suggest circuit-level mechanisms linking spatiotemporal levels of analysis and highlight the importance of local properties and their hierarchical specialization on the large-scale organization of human cortical dynamics.

PMID: 30744986 [PubMed - as supplied by publisher]

Alexithymia and frontal-amygdala functional connectivity in North Korean refugees.

Thu, 02/14/2019 - 03:15
Related Articles

Alexithymia and frontal-amygdala functional connectivity in North Korean refugees.

Psychol Med. 2019 Feb 12;:1-8

Authors: Kim N, Park I, Lee YJ, Jeon S, Kim S, Lee KH, Park J, Kim HK, Gwaq AR, Jun JY, Yoo SY, Lee SH, Kim SJ

Abstract
BACKGROUND: Refugees commonly experience difficulties with emotional processing, such as alexithymia, due to stressful or traumatic experiences. However, the functional connectivity of the amygdala, which is central to emotional processing, has yet to be assessed in refugees. Thus, the present study investigated the resting-state functional connectivity of the amygdala and its association with emotional processing in North Korean (NK) refugees.
METHODS: This study included 45 NK refugees and 40 native South Koreans (SK). All participants were administered the Toronto Alexithymia Scale (TAS), Beck Depression Inventory (BDI), and Clinician-administered PTSD Scale (CAPS), and differences between NK refugees and native SK in terms of resting-state functional connectivity of the amygdala were assessed. Additionally, the association between the strength of amygdala connectivity and the TAS score was examined.
RESULTS: Resting-state connectivity values from the left amygdala to the bilateral dorsolateral prefrontal cortex (dlPFC) and dorsal anterior cingulate cortex (dACC) were higher in NK refugees than in native SK. Additionally, the strength of connectivity between the left amygdala and right dlPFC was positively associated with TAS score after controlling for the number of traumatic experiences and BDI and CAPS scores.
CONCLUSIONS: The present study found that NK refugees exhibited heightened frontal-amygdala connectivity, and that this connectivity was correlated with alexithymia. The present results suggest that increased frontal-amygdala connectivity in refugees may represent frontal down-regulation of the amygdala, which in turn may produce alexithymia.

PMID: 30744720 [PubMed - as supplied by publisher]