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Spontaneous brain activity underlying auditory hallucinations in the hearing-impaired.

Sat, 01/16/2021 - 21:51
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Spontaneous brain activity underlying auditory hallucinations in the hearing-impaired.

Cortex. 2021 Jan 05;136:1-13

Authors: Marschall TM, Ćurčić-Blake B, Brederoo SG, Renken RJ, Linszen MMJ, Koops S, Sommer IEC

Abstract
Auditory hallucinations, the perception of a sound without a corresponding source, are common in people with hearing impairment. Two forms can be distinguished: simple (i.e., tinnitus) and complex hallucinations (speech and music). Little is known about the precise mechanisms underlying these types of hallucinations. Here we tested the assumption that spontaneous activity in the auditory pathways, following deafferentation, underlies these hallucinations and is related to their phenomenology. By extracting (fractional) Amplitude of Low Frequency Fluctuation [(f)ALFF] scores from resting state fMRI of 18 hearing impaired patients with complex hallucinations (voices or music), 18 hearing impaired patients with simple hallucinations (tinnitus or murmuring), and 20 controls with normal hearing, we investigated differences in spontaneous brain activity between these groups. Spontaneous activity in the anterior and posterior cingulate cortex of hearing-impaired groups was significantly higher than in the controls. The group with complex hallucinations showed elevated activity in the bilateral temporal cortex including Wernicke's area, while spontaneous activity of the group with simple hallucinations was mainly located in the cerebellum. These results suggest a decrease in error monitoring in both hearing-impaired groups. Spontaneous activity of language-related areas only in complex hallucinations suggests that the manifestation of the spontaneous activity represents the phenomenology of the hallucination. The link between cerebellar activity and simple hallucinations, such as tinnitus, is new and may have consequences for treatment.

PMID: 33450598 [PubMed - as supplied by publisher]

Boost in Test-Retest Reliability in Resting State fMRI with Predictive Modeling.

Sat, 01/16/2021 - 21:51
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Boost in Test-Retest Reliability in Resting State fMRI with Predictive Modeling.

Cereb Cortex. 2021 Jan 14;:

Authors: Taxali A, Angstadt M, Rutherford S, Sripada C

Abstract
Recent studies found low test-retest reliability in functional magnetic resonance imaging (fMRI), raising serious concerns among researchers, but these studies mostly focused on the reliability of individual fMRI features (e.g., individual connections in resting state connectivity maps). Meanwhile, neuroimaging researchers increasingly employ multivariate predictive models that aggregate information across a large number of features to predict outcomes of interest, but the test-retest reliability of predicted outcomes of these models has not previously been systematically studied. Here we apply 10 predictive modeling methods to resting state connectivity maps from the Human Connectome Project dataset to predict 61 outcome variables. Compared with mean reliability of individual resting state connections, we find mean reliability of the predicted outcomes of predictive models is substantially higher for all 10 modeling methods assessed. Moreover, improvement was consistently observed across all scanning and processing choices (i.e., scan lengths, censoring thresholds, volume- vs. surface-based processing). For the most reliable methods, the reliability of predicted outcomes was mostly, though not exclusively, in the "good" range (above 0.60). Finally, we identified three mechanisms that help to explain why predicted outcomes of predictive models have higher reliability than individual imaging features. We conclude that researchers can potentially achieve higher test-retest reliability by making greater use of predictive models.

PMID: 33447841 [PubMed - as supplied by publisher]

Individual-fMRI-approaches reveal cerebellum and visual communities to be functionally connected in obsessive compulsive disorder.

Sat, 01/16/2021 - 21:51
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Individual-fMRI-approaches reveal cerebellum and visual communities to be functionally connected in obsessive compulsive disorder.

Sci Rep. 2021 Jan 14;11(1):1354

Authors: Kashyap R, Eng GK, Bhattacharjee S, Gupta B, Ho R, Ho CSH, Zhang M, Mahendran R, Sim K, Chen SHA

Abstract
There is significant interest in understanding the pathophysiology of Obsessive-Compulsive Disorder (OCD) using resting-state fMRI (rsfMRI). Previous studies acknowledge abnormalities within and beyond the fronto-striato-limbic circuit in OCD that require further clarifications. However, limited information could be inferred from the conventional way of investigating the functional connectivity differences between OCD and healthy controls. Here, we identified altered brain organization in patients with OCD by applying individual-based approaches to maximize the identification of underlying network-based features specific to the OCD group. rsfMRI of 20 patients with OCD and 22 controls were preprocessed, and individual-fMRI-subspace was derived for each subject within each group. We evaluated group differences in functional connectivity using individual-fMRI-subspace and established its advantage over conventional-fMRI methodology. We applied prediction-based approaches to highlight the group differences by evaluating the differences in functional connections that predicted the clinical scores (namely, the Obsessive-Compulsive Inventory-Revised (OCI-R) and Hamilton Anxiety Rating Scale). Then, we explored the brain network organization of both groups by estimating the subject-specific communities within each group. Lastly, we evaluated associations between the inter-individual variation of nodes in the communities to clinical measures using linear regression. Functional connectivity analysis using individual-fMRI-subspace detected 83 connections that were different between OCD and control groups, compared to none found using conventional-fMRI methodology. Connectome-based prediction analysis did not show significant overlap between the two groups in the functional connections that predicted the clinical scores. This suggests that the functional architecture in patients with OCD may be different compared to controls. Seven communities were found in both groups. Interestingly, within the OCD group but not controls, we observed functional connectivity between cerebellar and visual regions, and lack of connectivity between striato-limbic and frontal areas. Inter-individual variations in the community-size of these two communities were also associated with the OCI-R score (p < .005). Due to our small sample size, we further validated our results by (i) accounting for head motion, (ii) applying global signal regression (GSR) in data processing, and (iii) using an alternate atlas for parcellation. While the main results were consistently observed with accounting for head motion and using another atlas, the key findings were not reproduced with GSR application. The study demonstrated the existence of disconnectedness in fronto-striato-limbic community and connectedness between cerebellar and visual areas in OCD patients, which was also related to the clinical symptomatology of OCD.

PMID: 33446780 [PubMed - in process]

Test-retest reliability of laser evoked pain perception and fMRI BOLD responses.

Sat, 01/16/2021 - 21:51
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Test-retest reliability of laser evoked pain perception and fMRI BOLD responses.

Sci Rep. 2021 Jan 14;11(1):1322

Authors: Bi Y, Hou X, Zhong J, Hu L

Abstract
Pain perception is a subjective experience and highly variable across time. Brain responses evoked by nociceptive stimuli are highly associated with pain perception and also showed considerable variability. To date, the test-retest reliability of laser-evoked pain perception and its associated brain responses across sessions remain unclear. Here, an experiment with a within-subject repeated-measures design was performed in 22 healthy volunteers. Radiant-heat laser stimuli were delivered on subjects' left-hand dorsum in two sessions separated by 1-5 days. We observed that laser-evoked pain perception was significantly declined across sessions, coupled with decreased brain responses in the bilateral primary somatosensory cortex (S1), right primary motor cortex, supplementary motor area, and middle cingulate cortex. Intraclass correlation coefficients between the two sessions showed "fair" to "moderate" test-retest reliability for pain perception and brain responses. Additionally, we observed lower resting-state brain activity in the right S1 and lower resting-state functional connectivity between right S1 and dorsolateral prefrontal cortex in the second session than the first session. Altogether, being possibly influenced by changes of baseline mental state, laser-evoked pain perception and brain responses showed considerable across-session variability. This phenomenon should be considered when designing experiments for laboratory studies and evaluating pain abnormalities in clinical practice.

PMID: 33446726 [PubMed - in process]

Differential response to SSRI versus Placebo and distinct neural signatures among data-driven subgroups of patients with major depressive disorder.

Fri, 01/15/2021 - 21:51
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Differential response to SSRI versus Placebo and distinct neural signatures among data-driven subgroups of patients with major depressive disorder.

J Affect Disord. 2020 Dec 28;282:602-610

Authors: Chin Fatt CR, Cooper CM, Jha MK, Minhajuddin A, Rush AJ, Trombello JM, Fava M, McInnis M, Weissman M, Trivedi MH

Abstract
OBJECTIVE: To identify data-driven subgroups in Major Depressive Disorder (MDD) in order to elucidate underlying neural correlates and determine if these subgroups have utility in predicting response to antidepressant versus placebo.
METHODS: Using 27 clinical measures at baseline of Establishing Moderators and Biosignatures of Antidepressant Response for Clinical Care for Depression (EMBARC) study, participants with MDD (n=244) were sub grouped using principal component (PC) analysis. Baseline-to-week-8 changes in depression severity with sertraline versus placebo were compared in these subgroups. Resting-state functional connectivity of these subgroups were compared to those of healthy controls (n=38).
RESULTS: Eight subgroups were identified from four PCs: (PC1) severity of depression-associated symptoms, (PC2) sub-threshold mania and anhedonia, (PC3) childhood trauma, medical comorbidities, and sexual dysfunction, and (PC4) personality traits of openness and agreeableness. Participants with high childhood trauma experienced greater improvement with sertraline (Cohen's d=0.87), whereas those with either higher levels of subthreshold hypomanic symptoms (Cohen's d=0.67) or with lower levels of agreeableness and openness experienced greater improvement with placebo (Cohen's d=0.71). Participants with high childhood trauma had greater connectivity between salience and dorsal attention networks, whereas those with higher levels of subthreshold hypomanic symptoms and lower levels of agreeableness and openness had greater connectivity within limbic network and that of visual network with hippocampus and dorsal attention network.
CONCLUSION: Assessing history of childhood trauma, presence of subthreshold hypomanic symptoms and personality traits may help to identify subgroups of patients with MDD who respond differentially to sertraline or placebo and have distinct neural signatures.

PMID: 33445082 [PubMed - as supplied by publisher]

Altered brain intrinsic functional hubs and connectivity associated with relapse risk in heroin dependents undergoing methadone maintenance treatment: A resting-state fMRI study.

Fri, 01/15/2021 - 21:51
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Altered brain intrinsic functional hubs and connectivity associated with relapse risk in heroin dependents undergoing methadone maintenance treatment: A resting-state fMRI study.

Drug Alcohol Depend. 2021 Jan 02;219:108503

Authors: Wang L, Hu F, Wang W, Li Q, Li Y, Zhu J, Qin Y, Shi H, Li W, Wang Y

Abstract
BACKGROUND: The neural substrates underlying the relapse behavior of heroin dependents (HD) who received long-term methadone maintenance treatment (MMT) have yet to be thoroughly expounded. This study investigated the relapse-related intrinsic functional hubs of HD and their functional integration feature at whole brain network level.
METHODS: 57 male HD receiving MMT and 49 matched healthy controls (HC) were enrolled. All of the subjects received resting-state functional magnetic resonance imaging scan. And the 57 patients were assigned a 26-month follow-up for collecting illegal drug use information. Of them, 11 were non-relapsers and 46 relapsers. We analyzed the voxel-based degree centrality (DC) to reveal the differences in nodule centrality between HD and HC, conducted Pearson partial-correlation analysis to confirm the relationship between relapse frequency and DC value of the nodes with significant intergroup differences, and finally compared the functional connectivity (FC) of the relapse-related hubs between non-relapsers and relapsers.
RESULTS: We found the DC values of right insula and left nucleus accumbens (NAc) were negatively correlated with relapse frequency. Compared with the non-relapsers, the relapsers had a significant decreased FC between left NAc and inhibitory control circuitry, including left dorsolateral prefrontal cortex, left inferior frontal gyrus and motor regions.
CONCLUSIONS: These findings suggest that the neural substrates of relapse vulnerability in HD undergoing MMT are the intrinsic functional hubs of introceptive and reward systems and the latter modulates relapse behavior via interaction with inhibitory control circuit.

PMID: 33444899 [PubMed - as supplied by publisher]

A novel fully immersive virtual reality environment for upper extremity rehabilitation in patients with stroke.

Fri, 01/15/2021 - 21:51
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A novel fully immersive virtual reality environment for upper extremity rehabilitation in patients with stroke.

Ann N Y Acad Sci. 2021 Jan 14;:

Authors: Mekbib DB, Debeli DK, Zhang L, Fang S, Shao Y, Yang W, Han J, Jiang H, Zhu J, Zhao Z, Cheng R, Ye X, Zhang J, Xu D

Abstract
Given the rising incidence of stroke, several technology-driven methods for rehabilitation have recently been developed. Virtual reality (VR) is a promising therapeutic technology among them. We recently developed a neuroscientifically grounded VR system to aid recovery of motor function poststroke. The developed system provides unilateral and bilateral upper extremity (UE) training in a fully immersive virtual environment that may stimulate and activate mirror neurons (MNs) in the brain necessary for UE rehabilitation. Twenty-three participants were randomized to a VR group (n = 12) to receive VR intervention (8 h within 2 weeks) plus 8-h occupational therapy (OT) or a control group (n = 11) to receive time-matched OT alone. Treatment effects on motor recovery and cortical reorganization were investigated using the Barthel Index (BI), Fugl-Meyer Upper Extremity (FM-UE), and resting-state fMRI. Both groups significantly improved BI (P < 0.05), reflecting the recovery of UE motor function. The VR group revealed significant improvements on FM-UE scores (P < 0.05) than the control group. Neural activity increased after the intervention, particularly in the brain areas implicating MNs, such as in the primary motor cortex. Overall, results suggested that using a neuroscientifically grounded VR system might offer additional benefits for UE rehabilitation in patients receiving OT.

PMID: 33442915 [PubMed - as supplied by publisher]

Resting-state functional connectivity predicts recovery from visually induced motion sickness.

Fri, 01/15/2021 - 21:51
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Resting-state functional connectivity predicts recovery from visually induced motion sickness.

Exp Brain Res. 2021 Jan 13;:

Authors: Miyazaki J, Yamamoto H, Ichimura Y, Yamashiro H, Murase T, Yamamoto T, Umeda M, Higuchi T

Abstract
Movies depicting certain types of motion often provoke uncomfortable symptoms similar to motion sickness, termed visually induced motion sickness (VIMS). VIMS generally evolves slowly during the viewing of a motion stimulus and, when the stimulus is removed, the recovery proceeds over time. Recent human neuroimaging studies have provided new insights into the neural bases of the evolution of VIMS. In contrast, no study has investigated the neural correlates of the recovery from VIMS. Study of the recovery process is critical for the development of a way to promote recovery and could provide further clues for understanding the mechanisms of VIMS. We thus investigated brain activity during the recovery from VIMS with functional connectivity magnetic resonance imaging. We found enhanced recovery-related functional connectivity patterns involving brain areas such as the insular, cingulate and visual cortical regions, which have been suggested to play important roles in the emergence of VIMS. These regions also constituted large interactive networks. Furthermore, the increase in functional connectivity was correlated with the subjective awareness of recovery for the following five pairs of brain regions: insula-superior temporal gyrus, claustrum-left and right inferior parietal lobules, claustrum-superior temporal gyrus and superior frontal gyrus-lentiform nucleus. Considering the previous findings on the functions of these regions and the present results, it is suggested that the increase in FC may reflect brain processes such as enhanced interoceptive awareness to one's own bodily state, a neuroplastic change in visual-processing circuits and/or the maintenance of visual spatial memory.

PMID: 33442756 [PubMed - as supplied by publisher]

Role of the Nucleus Basalis as a Key Network Node in Temporal Lobe Epilepsy.

Fri, 01/15/2021 - 21:51
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Role of the Nucleus Basalis as a Key Network Node in Temporal Lobe Epilepsy.

Neurology. 2021 Jan 13;:

Authors: González HFJ, Narasimhan S, Johnson GW, Wills KE, Haas KF, Konrad PE, Chang C, Morgan VL, Rubinov M, Englot DJ

Abstract
OBJECTIVE: To determine if nucleus basalis of Meynert (NBM) may be a key network structure of altered functional connectivity in temporal lobe epilepsy (TLE), we examined fMRI with network based analyses.
METHODS: We acquired resting-state fMRI in 40 adults with TLE and 40 matched healthy control participants. We calculated functional connectivity of NBM and used multiple complementary network based analyses to explore the importance of NBM in TLE networks without biasing our results by our approach. We compared patients to controls and examined associations of network properties with disease metrics and neurocognitive testing.
RESULTS: We observed marked decreases in connectivity between NBM and the rest of the brain in patients with TLE(0.91±0.88, mean±SD) versus controls(1.96±1.13,p<0.001 t-test). Larger decreases in connectivity between NBM and fronto-parietal-insular regions were associated with higher frequency of consciousness-impairing seizures(r=-0.41, p=0.008, Pearson). A core network of altered nodes in TLE included NBM ipsilateral to the epileptogenic side and bilateral limbic structures. Further, normal community affiliation of ipsilateral NBM was lost in patients, and this structure displayed the most altered clustering coefficient of any node examined(3.46±1.17 controls versus 2.23±0.93 patients). Abnormal connectivity between NBM and subcortical arousal community was associated with modest neurocognitive deficits. Finally, a logistic regression model incorporating connectivity properties of ipsilateral NBM successfully distinguished patients versus control datasets with moderately high accuracy(78%).
CONCLUSIONS: These results suggest that while NBM is rarely studied in epilepsy, it may be one of the most perturbed network nodes in TLE, contributing to widespread neural effects in this disabling disorder.

PMID: 33441453 [PubMed - as supplied by publisher]

Brain functional changes in perimenopausal women: an amplitude of low-frequency fluctuation study.

Thu, 01/14/2021 - 21:50
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Brain functional changes in perimenopausal women: an amplitude of low-frequency fluctuation study.

Menopause. 2021 Jan 11;Publish Ahead of Print:

Authors: Liu N, Zhang Y, Liu S, Zhang X, Liu H

Abstract
OBJECTIVE: To evaluate the effects of sex hormones on amplitude of low-frequency fluctuation (ALFF) in brain regions related to cognition in perimenopausal women.
METHODS: This cross-sectional study involved 25 perimenopausal women and 25 premenopausal women who underwent behavioral evaluations, sex hormone level measurements, and functional magnetic resonance imaging (fMRI). All data and ALFF analyses were preprocessed using the Data Processing Assistant for Resting-State fMRI. Statistical analyses were performed using the Resting-State fMRI Data Analysis Toolkit to explore the differences in ALFF between perimenopausal and premenopausal women. The gray matter volume (GMV) values extracted from brain regions (regions of interest) with significantly different ALFF values between the perimenopausal and premenopausal groups were compared. We analyzed the correlations of the ALFF and GMV values of these regions of interest with the results of behavioral evaluations and sex hormone levels in the two groups.
RESULTS: Compared with the premenopausal group, the perimenopausal group showed significant ALFF increase in the left gyrus rectus. Regions with decreased ALFF in the perimenopausal group included the left superior temporal gyrus, left inferior frontal gyrus, and left insula. The GMV values of the left gyrus rectus and left superior temporal gyrus were reduced in perimenopausal women. Furthermore, the estradiol level was negatively correlated with the ALFF value of the left gyrus rectus in perimenopausal women.
CONCLUSIONS: The ALFF and GMV values of certain brain regions related to cognitive function were changed in perimenopausal women. Such functional brain alterations may provide more information regarding the mechanism of cognitive dysfunction in perimenopausal women.

PMID: 33438891 [PubMed - as supplied by publisher]

Default mode and salience network alterations in suicidal and non-suicidal self-injurious thoughts and behaviors in adolescents with depression.

Thu, 01/14/2021 - 21:50
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Default mode and salience network alterations in suicidal and non-suicidal self-injurious thoughts and behaviors in adolescents with depression.

Transl Psychiatry. 2021 Jan 12;11(1):38

Authors: Ho TC, Walker JC, Teresi GI, Kulla A, Kirshenbaum JS, Gifuni AJ, Singh MK, Gotlib IH

Abstract
Suicidal ideation (SI) and non-suicidal self-injury (NSSI) are two distinct yet often co-occurring risk factors for suicide deaths in adolescents. Elucidating the neurobiological patterns that specifically characterize SI and NSSI in adolescents is needed to inform the use of these markers in intervention studies and to develop brain-based treatment targets. Here, we clinically assessed 70 adolescents-49 adolescents with depression and 21 healthy controls-to determine SI and NSSI history. Twenty-eight of the depressed adolescents had a history of SI and 29 had a history of NSSI (20 overlapping). All participants underwent a resting-state fMRI scan. We compared groups in network coherence of subdivisions of the central executive network (CEN), default mode network (DMN), and salience network (SN). We also examined group differences in between-network connectivity and explored brain-behavior correlations. Depressed adolescents with SI and with NSSI had lower coherence in the ventral DMN compared to those without SI or NSSI, respectively, and healthy controls (all ps < 0.043, uncorrected). Depressed adolescents with NSSI had lower coherence in the anterior DMN and in insula-SN (all ps < 0.030, uncorrected), and higher CEN-DMN connectivity compared to those without NSSI and healthy controls (all ps < 0.030, uncorrected). Lower network coherence in all DMN subnetworks and insula-SN were associated with higher past-month SI and NSSI (all ps < 0.001, uncorrected). Thus, in our sample, both SI and NSSI are related to brain networks associated with difficulties in self-referential processing and future planning, while NSSI specifically is related to brain networks associated with disruptions in interoceptive awareness.

PMID: 33436537 [PubMed - in process]

Time-Varying Functional Connectivity Decreases as a Function of Acute Nicotine Abstinence.

Thu, 01/14/2021 - 21:50
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Time-Varying Functional Connectivity Decreases as a Function of Acute Nicotine Abstinence.

Biol Psychiatry Cogn Neurosci Neuroimaging. 2020 Oct 19;:

Authors: Fedota JR, Ross TJ, Castillo J, McKenna MR, Matous AL, Salmeron BJ, Menon V, Stein EA

Abstract
BACKGROUND: The nicotine withdrawal syndrome (NWS) includes affective and cognitive disruptions whose incidence and severity vary across time during acute abstinence. However, most network-level neuroimaging uses static measures of resting-state functional connectivity and assumes time-invariance and is thus unable to capture dynamic brain-behavior relationships. Recent advances in resting-state functional connectivity signal processing allow characterization of time-varying functional connectivity (TVFC), which characterizes network communication between networks that reconfigure over the course of data collection. Therefore, TVFC may more fully describe network dysfunction related to the NWS.
METHODS: To isolate alterations in the frequency and diversity of communication across network boundaries during acute nicotine abstinence, we scanned 25 cigarette smokers in the nicotine-sated and abstinent states and applied a previously validated method to characterize TVFC at a network and a nodal level within the brain.
RESULTS: During abstinence, we found brain-wide decreases in the frequency of interactions between network nodes in different modular communities (i.e., temporal flexibility). In addition, within a subset of the networks examined, the variability of these interactions across community boundaries (i.e., spatiotemporal diversity) also decreased. Finally, within 2 of these networks, the decrease in spatiotemporal diversity was significantly related to NWS clinical symptoms.
CONCLUSIONS: Using multiple measures of TVFC in a within-subjects design, we characterized a novel set of changes in network communication and linked these changes to specific behavioral symptoms of the NWS. These reductions in TVFC provide a meso-scale network description of the relative inflexibility of specific large-scale brain networks during acute abstinence.

PMID: 33436331 [PubMed - as supplied by publisher]

Diagnostic Task Specific Activations in Functional MRI and Aberrant Connectivity of Insula with Middle Frontal Gyrus Can Inform the Differential Diagnosis of Psychosis.

Thu, 01/14/2021 - 21:50
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Diagnostic Task Specific Activations in Functional MRI and Aberrant Connectivity of Insula with Middle Frontal Gyrus Can Inform the Differential Diagnosis of Psychosis.

Diagnostics (Basel). 2021 Jan 08;11(1):

Authors: Stoyanov D, Aryutova K, Kandilarova S, Paunova R, Arabadzhiev Z, Todeva-Radneva A, Kostianev S, Borgwardt S

Abstract
We constructed a novel design integrating the administration of a clinical self-assessment scale with simultaneous acquisition of functional Magnetic Resonance Imaging (fMRI), aiming at cross-validation between psychopathology evaluation and neuroimaging techniques. We hypothesized that areas demonstrating differential activation in two groups of patients (the first group exhibiting paranoid delusions in the context of paranoid schizophrenia-SCH-and second group with a depressive episode in the context of major depressive disorder or bipolar disorder-DEP) will have distinct connectivity patterns and structural differences. Fifty-one patients with SCH (n = 25) or DEP (n = 26) were scanned with three different MRI sequences: a structural and two functional sequences-resting-state and task-related fMRI (the stimuli represent items from a paranoid-depressive self-evaluation scale). While no significant differences were found in gray matter volumes, we were able to discriminate between the two clinical entities by identifying two significant clusters of activations in the SCH group-the left Precuneus (PreCu) extending to the left Posterior Cingulate Cortex (PCC) and the right Angular Gyrus (AG). Additionally, the effective connectivity of the middle frontal gyrus (MFG), a part of the Dorsolateral Prefrontal Cortex (DLPFC) to the Anterior Insula (AI), demonstrated a significant difference between the two groups with inhibitory connection demonstrated only in SCH. The observed activations of PreCu, PCC, and AG (involved in the Default Mode Network DMN) might be indirect evidence of the inhibitory connection from the DLPFC to AI, interfering with the balancing function of the insula as the dynamic switch in the DMN. The findings of our current study might suggest that the connectivity from DLPFC to the anterior insula can be interpreted as evidence for the presence of an aberrant network that leads to behavioral abnormalities, the manifestation of which depends on the direction of influence. The reduced effective connectivity from the AI to the DLPFC is manifested as depressive symptoms, and the inhibitory effect from the DLPFC to the AI is reflected in the paranoid symptoms of schizophrenia.

PMID: 33435624 [PubMed]

Multiple overlapping dynamic patterns of the visual sensory network in schizophrenia.

Thu, 01/14/2021 - 00:50
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Multiple overlapping dynamic patterns of the visual sensory network in schizophrenia.

Schizophr Res. 2021 Jan 09;228:103-111

Authors: Sendi MSE, Pearlson GD, Mathalon DH, Ford JM, Preda A, van Erp TGM, Calhoun VD

Abstract
Although visual processing impairments have been explored in schizophrenia (SZ), their underlying neurobiology of the visual processing impairments has not been widely studied. Also, while some research has hinted at differences in information transfer and flow in SZ, there are few investigations of the dynamics of functional connectivity within visual networks. In this study, we analyzed resting-state fMRI data of the visual sensory network (VSN) in 160 healthy control (HC) subjects and 151 SZ subjects. We estimated 9 independent components within the VSN. Then, we calculated the dynamic functional network connectivity (dFNC) using the Pearson correlation. Next, using k-means clustering, we partitioned the dFNCs into five distinct states, and then we calculated the portion of time each subject spent in each state, which we termed the occupancy rate (OCR). Using OCR, we compared HC with SZ subjects and investigated the link between OCR and visual learning in SZ subjects. Besides, we compared the VSN functional connectivity of SZ and HC subjects in each state. We found that this network is indeed highly dynamic. Each state represents a unique connectivity pattern of fluctuations in VSN FNC, and all states showed significant disruption in SZ. Overall, HC showed stronger connectivity within the VSN in states. SZ subjects spent more time in a state in which the connectivity between the middle temporal gyrus and other regions of VNS is highly negative. Besides, OCR in a state with strong positive connectivity between the middle temporal gyrus and other regions correlated significantly with visual learning scores in SZ.

PMID: 33434723 [PubMed - as supplied by publisher]

The manifestation of individual differences in sensitivity to punishment during resting state is modulated by eye state.

Thu, 01/14/2021 - 00:50
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The manifestation of individual differences in sensitivity to punishment during resting state is modulated by eye state.

Cogn Affect Behav Neurosci. 2021 Jan 12;:

Authors: Costumero V, Adrián-Ventura J, Bueichekú E, Miró-Padilla A, Palomar-García MÁ, Marin-Marin L, Villar-Rodríguez E, Aguirre N, Barrós-Loscertales A, Ávila C

Abstract
Structural and functional neuroimaging studies have shown that brain areas associated with fear and anxiety (defensive system areas) are modulated by individual differences in sensitivity to punishment (SP). However, little is known about how SP is related to brain functional connectivity and the factors that modulate this relationship. In this study, we investigated whether a simple methodological manipulation, such as performing a resting state with eyes open or eyes closed, can modulate the manifestation of individual differences in SP. To this end, we performed an exploratory fMRI resting state study in which a group of participants (n = 88) performed a resting state with eyes closed and another group (n = 56) performed a resting state with eyes open. All participants completed the Sensitivity to Punishment and Sensitivity to Reward Questionnaire. Seed-based functional connectivity analyses were performed in the amygdala, hippocampus, and periaqueductal gray (PAG). Our results showed that the relationship between SP and left amygdala-precuneus and left hippocampus-precuneus functional connectivity was modulated by eye state. Moreover, in the eyes open group, SP was negatively related to the functional connectivity between the PAG and amygdala and between the PAG and left hippocampus, and it was positively related to the functional connectivity between the amygdala and hippocampus. Together, our results may suggest underlying differences in the connectivity between anxiety-related areas based on eye state, which in turn would affect the manifestation of individual differences in SP.

PMID: 33432544 [PubMed - as supplied by publisher]

Functional connectivity patterns of the subgenual anterior cingulate cortex in first-episode refractory major depressive disorder.

Thu, 01/14/2021 - 00:50
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Functional connectivity patterns of the subgenual anterior cingulate cortex in first-episode refractory major depressive disorder.

Brain Imaging Behav. 2021 Jan 12;:

Authors: Cheng B, Meng Y, Zuo Y, Guo Y, Wang X, Wang S, Zhang R, Deng W, Guo Y, Ning G

Abstract
Although accumulating evidence has been elucidating the neuronal basis of refractory/nonrefractory major depressive disorder (rMDD/nrMDD), the results are inconsistent, and little is known about the distinct neural mechanisms underlying rMDD. Here, we explored the convergent/divergent brain networks between first-episode MDD subtypes using the resting-state functional connectivity (RSFC) approach. In total, 33 healthy controls (HCs), 31 first-episode rMDD patients and 33 first-episode nrMDD patients were enrolled and underwent MRI scanning. The left subgenual anterior cingulate cortex (sgACC) was selected as the seed region, and RSFC was employed to evaluate associations between the seed and other regions in the whole brain. Both MDD subtypes exhibited convergent left sgACC-based neural networks, including increased RSFC with the dorsal prefrontal cortex (DPFC) and decreased RSFC with the bilateral orbitofrontal cortex (OFC) and right parahippocampus. rMDD patients exhibited increased left sgACC-OFC RSFC relative to nrMDD patients, and RSFC with the bilateral OFC in rMDD patients was negatively correlated with HAMD scores. These findings confirmed our speculation that convergent and divergent neural networks exist between rMDD and nrMDD. Cortical-limbic circuits, especially the prefrontal-limbic circuit, may serve as the convergent dysfunctional neural circuitry in MDD subtypes. As an important biomarker, a unique OFC-sgACC circuit abnormality was identified in rMDD patients, which might help elucidate the underlying mechanism regarding treatment responses in rMDD patients.

PMID: 33432537 [PubMed - as supplied by publisher]

Counteracting Effects of Glutathione on the Glutamate-Driven Excitation/Inhibition Imbalance in First-Episode Schizophrenia: A 7T MRS and Dynamic Causal Modeling Study.

Thu, 01/14/2021 - 00:50
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Counteracting Effects of Glutathione on the Glutamate-Driven Excitation/Inhibition Imbalance in First-Episode Schizophrenia: A 7T MRS and Dynamic Causal Modeling Study.

Antioxidants (Basel). 2021 Jan 08;10(1):

Authors: Limongi R, Jeon P, Théberge J, Palaniyappan L

Abstract
Oxidative stress plays a key role in the pathophysiology of schizophrenia. While free radicals produced by glutamatergic excess and oxidative metabolism have damaging effects on brain tissue, antioxidants such as glutathione (GSH) counteract these effects. The interaction between glutamate (GLU) and GSH is centered on N-Methyl-D-aspartate (NMDA) receptors. GSH levels increase during glutamate-mediated excitatory neuronal activity, which serves as a checkpoint to protect neurons from oxidative damage and reduce excitatory overdrive. We studied the possible influence of GSH on the glutamate-mediated dysconnectivity in 19 first-episode schizophrenia (FES) patients and 20 healthy control (HC) subjects. Using ultra-high field (7 Tesla) magnetic resonance spectroscopy (MRS) and resting state functional magnetic resonance imaging (fMRI), we measured GSH and GLU levels in the dorsal anterior cingulate cortex (dACC) and blood-oxygenation level-dependent activity in both the dACC and the anterior insula (AI). Using spectral dynamic causal modeling, we found that when compared to HCs, in FES patients inhibitory activity within the dACC decreased with GLU levels whereas inhibitory activity in both the dACC and AI increased with GSH levels. Our model explains how higher levels of GSH can reverse the downstream pathophysiological effects of a hyperglutamatergic state in FES. This provides an initial insight into the possible mechanistic effect of antioxidant system on the excitatory overdrive in the salience network (dACC-AI).

PMID: 33430154 [PubMed]

Heritability of Functional Connectivity in Resting State: Assessment of the Dynamic Mean, Dynamic Variance, and Static Connectivity across Networks.

Wed, 01/13/2021 - 00:49
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Heritability of Functional Connectivity in Resting State: Assessment of the Dynamic Mean, Dynamic Variance, and Static Connectivity across Networks.

Cereb Cortex. 2021 Jan 12;:

Authors: Barber AD, Hegarty CE, Lindquist M, Karlsgodt KH

Abstract
Recent efforts to evaluate the heritability of the brain's functional connectome have predominantly focused on static connectivity. However, evaluating connectivity changes across time can provide valuable insight about the inherent dynamic nature of brain function. Here, the heritability of Human Connectome Project resting-state fMRI data was examined to determine whether there is a genetic basis for dynamic fluctuations in functional connectivity. The dynamic connectivity variance, in addition to the dynamic mean and standard static connectivity, was evaluated. Heritability was estimated using Accelerated Permutation Inference for the ACE (APACE), which models the additive genetic (h2), common environmental (c2), and unique environmental (e2) variance. Heritability was moderate (mean h2: dynamic mean = 0.35, dynamic variance = 0.45, and static = 0.37) and tended to be greater for dynamic variance compared to either dynamic mean or static connectivity. Further, heritability of dynamic variance was reliable across both sessions for several network connections, particularly between higher-order cognitive and visual networks. For both dynamic mean and static connectivity, similar patterns of heritability were found across networks. The findings support the notion that dynamic connectivity is genetically influenced. The flexibility of network connections, not just their strength, is a heritable endophenotype that may predispose trait behavior.

PMID: 33429433 [PubMed - as supplied by publisher]

Global Functional Network Connectivity Disturbances in Parkinson's Disease with Mild Cognitive Impairment by Resting-State Functional MRI.

Wed, 01/13/2021 - 00:49
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Global Functional Network Connectivity Disturbances in Parkinson's Disease with Mild Cognitive Impairment by Resting-State Functional MRI.

Curr Med Sci. 2020 Dec;40(6):1057-1066

Authors: Shuai XX, Kong XC, Zou Y, Wang SQ, Wang YH

Abstract
Examining the spontaneous BOLD activity to understand the neural mechanism of Parkinson's disease (PD) with mild cognitive impairment (MCI) is a focus in resting-state functional MRI (rs-fMRI) studies. This study aimed to investigate the alteration of brain functional connectivity in PD with MCI in a systematical way at two levels: functional connectivity analysis within resting state networks (RSNs) and functional network connectivity (FNC) analysis. Using group independent component analysis (ICA) on rs-fMRI data acquired from 30 participants (14 healthy controls and 16 PD patients with MCI), 16 RSNs were identified, and functional connectivity analysis within the RSNs and FNC analysis were carried out between groups. Compared to controls, patients with PD showed decreased functional connectivity within putamen network, thalamus network, cerebellar network, attention network, and self-referential network, and increased functional connectivity within execution network. Globally disturbed, mostly increased functional connectivity of FNC was observed in PD group, and insular network and execution network were the dominant network with extensively increased functional connectivity with other RSNs. Cerebellar network showed decreased functional connectivity with caudate network, insular network, and self-referential network. In general, decreased functional connectivity within RSNs and globally disturbed, mostly increased functional connectivity of FNC may be characteristics of PD. Increased functional connectivity within execution network may be an early marker of PD. The multi-perspective study based on RSNs may be a valuable means to assess functional changes corresponding to specific RSN, contributing to the understanding of the neural mechanism of PD.

PMID: 33428133 [PubMed - as supplied by publisher]

Chronic generalized pain disrupts whole brain functional connectivity in mice.

Wed, 01/13/2021 - 00:49
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Chronic generalized pain disrupts whole brain functional connectivity in mice.

Brain Imaging Behav. 2021 Jan 11;:

Authors: Nasseef MT, Ma W, Singh JP, Dozono N, Lançon K, Séguéla P, Darcq E, Ueda H, Kieffer BL

Abstract
Fibromyalgia (FM) is a generalized chronic pain condition whose pathophysiology is poorly understood, and both basic and translational research are needed to advance the field. Here we used the Sluka model to test whether FM-like pain in mice would produce detectable brain modifications using resting-state (rs) functional Magnetic Resonance Imaging (fMRI). Mice received intramuscular acid saline treatment, images were acquired at 7 T 5 days post-treatment, and pain thresholds tested 3 weeks post-scanning. Data-driven Independent Component Analysis revealed significant reduction of functional connectivity (FC) across several component pairs, with major changes for the Retrosplenial cortex (RSP) central to the default mode network, and to a lesser extent the Periaqueductal gray (PAG), a key pain processing area. Seed-to-seed analysis focused on 14 pain-related areas showed strongest FC reduction for RSP with several cortical areas (somatosensory, prefrontal and insular), and for PAG with both cortical (somatosensory) and subcortical (habenula, thalamus, parabrachial nucleus) areas. RSP-PAG FC was also reduced, and this decreased FC tended to be positively correlated with pain levels at individual subject level. Finally, seed-voxelwise analysis focused on PAG confirmed seed-to-seed findings and, also detected reduced PAG FC with the anterior cingulate cortex, increasingly studied in aversive pain effects. In conclusion, FM-like pain triggers FC alterations in the mouse, which are detected by rs-fMRI and are reminiscent of some human findings. The study reveals the causal fingerprint of FM-like pain in rodents, and indicates that both RSP and PAG connectional patterns could be suitable biomarkers, with mechanistic and translational value, for further investigations.

PMID: 33428113 [PubMed - as supplied by publisher]