New resting-state fMRI related studies at PubMed

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The Effect of Scan Length on the Assessment of BOLD Delay in Ischemic Stroke.

Thu, 05/21/2020 - 12:40

The Effect of Scan Length on the Assessment of BOLD Delay in Ischemic Stroke.

Front Neurol. 2020;11:381

Authors: Tanrıtanır AC, Villringer K, Galinovic I, Grittner U, Kirilina E, Fiebach JB, Villringer A, Khalil AA

Abstract
Objectives: To evaluate the impact of resting-state functional MRI scan length on the diagnostic accuracy, image quality and lesion volume estimation of BOLD delay maps used for brain perfusion assessment in acute ischemic stroke. Methods: Sixty-three acute ischemic stroke patients received a 340 s resting-state functional MRI within 24 h of stroke symptom onset. BOLD delay maps were calculated from the full scan and four shortened versions (68 s, 136 s, 204 s, 272 s). The BOLD delay lesions on these maps were compared in terms of spatial overlap and volumetric agreement with the lesions derived from the full scans and with time-to-maximum (Tmax) lesions derived from DSC-MRI in a subset of patients (n = 10). In addition, the interpretability and quality of these maps were compared across different scan lengths using mixed models. Results: Shortened BOLD delay scans showed a small volumetric bias (ranging from 0.05 to 5.3 mL; between a 0.13% volumetric underestimation and a 7.7% overestimation relative to the mean of the volumes, depending on scan length) compared to the full scan. Decreased scan length was associated with decreased spatial overlap with both the BOLD delay lesions derived from the full scans and with Tmax lesions. Only the two shortest scan lengths (68 and 136 s) were associated with substantially decreased interpretability, decreased structure clarity, and increased noisiness of BOLD delay maps. Conclusions: BOLD delay maps derived from resting-state fMRI scans lasting 272 and 204 s provide sufficient diagnostic quality and adequate assessment of perfusion lesion volumes. Such shortened scans may be helpful in situations where quick clinical decisions need to be made.

PMID: 32431665 [PubMed]

Comparison Analysis between the Medication Efficacy of the Milnacipran and Functional Connectivity of Neural Networks in Fibromyalgia Patients.

Thu, 05/21/2020 - 12:40

Comparison Analysis between the Medication Efficacy of the Milnacipran and Functional Connectivity of Neural Networks in Fibromyalgia Patients.

Brain Sci. 2020 May 15;10(5):

Authors: Kim SH, Lee MW, Kang MJ, Lee SG, Lee JG, Mun CW

Abstract
Milnacipran is a reuptake inhibitor of both serotonin and noradrenaline, used in the treatment of fibromyalgia with severe depression. However, few studies have been conducted on the efficacies of milnacipran drug on the functional connectivity of the neural network. The authors aimed to find the correlation between the drug efficacy and the changes in neural network in fibromyalgia patients. Resting-state-functional magnetic resonance imaging (rs-fMRI) were obtained before and after milnacipran drug administration. Graph theory indexes and small-worldness were calculated using preprocessed blood-oxygen-level-dependent signals from the rs-fMRI scans of 14 brain regions-of-interest. Statistical analyses were conducted to compare the topological network parameters. Significant changes in the neural network indexes appeared in three of the 14 brain regions-of-interest. In the pain network, the average path length on the left side of Brodmann area 32 was shortened. In the default mode network, functional connectivity changes were observed in the left lateral parietal cortex and medial prefrontal cortex. In the left lateral parietal cortex, the degree and betweenness centrality increased, whereas the clustering coefficient decreased. In the medial prefrontal cortex, local efficiency decreased. The small-worldness declined after milnacipran medication. The present results demonstrate that functional connectivity indexes in the brains of female fibromyalgia patients obtained from rs-fMRI data can be used as potential prognosis markers of milnacipran drug treatment.

PMID: 32429065 [PubMed]

Adolescent alcohol use disrupts functional neurodevelopment in sensation seeking girls.

Wed, 05/20/2020 - 18:00

Adolescent alcohol use disrupts functional neurodevelopment in sensation seeking girls.

Addict Biol. 2020 May 19;:e12914

Authors: Zhao Q, Sullivan EV, Műller-Oehring EM, Honnorat N, Adeli E, Podhajsky S, Baker FC, Colrain IM, Prouty D, Tapert SF, Brown SA, Meloy MJ, Brumback T, Nagel BJ, Morales AM, Clark DB, Luna B, De Bellis MD, Voyvodic JT, Nooner KB, Pfefferbaum A, Pohl KM

Abstract
Exogenous causes, such as alcohol use, and endogenous factors, such as temperament and sex, can modulate developmental trajectories of adolescent neurofunctional maturation. We examined how these factors affect sexual dimorphism in brain functional networks in youth drinking below diagnostic threshold for alcohol use disorder (AUD). Based on the 3-year, annually acquired, longitudinal resting-state functional magnetic resonance imaging (MRI) data of 526 adolescents (12-21 years at baseline) from the National Consortium on Alcohol and Neurodevelopment in Adolescence (NCANDA) cohort, developmental trajectories of 23 intrinsic functional networks (IFNs) were analyzed for (1) sexual dimorphism in 259 participants who were no-to-low drinkers throughout this period; (2) sex-alcohol interactions in two age- and sex-matched NCANDA subgroups (N = 76 each), half no-to-low, and half moderate-to-heavy drinkers; and (3) moderating effects of gender-specific alcohol dose effects and a multifactorial impulsivity measure on IFN connectivity in all NCANDA participants. Results showed that sex differences in no-to-low drinkers diminished with age in the inferior-occipital network, yet girls had weaker within-network connectivity than boys in six other networks. Effects of adolescent alcohol use were more pronounced in girls than boys in three IFNs. In particular, girls showed greater within-network connectivity in two motor networks with more alcohol consumption, and these effects were mediated by sensation-seeking only in girls. Our results implied that drinking might attenuate the naturally diminishing sexual differences by disrupting the maturation of network efficiency more severely in girls. The sex-alcohol-dose effect might explain why women are at higher risk of alcohol-related health and psychosocial consequences than men.

PMID: 32428984 [PubMed - as supplied by publisher]

Intrinsic functional architecture of the human speech processing network.

Wed, 05/20/2020 - 18:00

Intrinsic functional architecture of the human speech processing network.

Cortex. 2020 Apr 21;129:41-56

Authors: Abrams DA, Kochalka J, Bhide S, Ryali S, Menon V

Abstract
Speech engages distributed temporo-fronto-parietal brain regions, however a comprehensive understanding of its intrinsic functional network architecture is lacking. Here we investigate the human speech processing network using the largest sample to date, high temporal resolution resting-state fMRI data, network stability analysis, and theoretically informed models. Network consensus analysis revealed three stable functional modules encompassing: (1) superior temporal plane (STP) and Area Spt, (2) superior temporal sulcus (STS) + ventral frontoparietal cortex, and (3) dorsal frontoparietal cortex. The STS + ventral frontoparietal cortex module showed the highest participation coefficient, and a hub-like organization linking STP with frontoparietal cortical nodes. Node-wise analysis revealed key connectivity features underlying this modular architecture, including a leftward asymmetric connectivity profile, and differential connectivity of STS and STP, with frontoparietal cortex. Our findings, replicated across cohorts, reveal a tripartite functional network architecture supporting speech processing and provide a novel template for future studies.

PMID: 32428761 [PubMed - as supplied by publisher]

Resting-State Functional Connectome in Patients with Brain Tumors Before and After Surgical Resection.

Wed, 05/20/2020 - 18:00

Resting-State Functional Connectome in Patients with Brain Tumors Before and After Surgical Resection.

World Neurosurg. 2020 May 16;:

Authors: Sparacia G, Parla G, Lo Re V, Cannella R, Mamone G, Carollo V, Midiri M, Grasso G

Abstract
PURPOSE: High-grade glioma (HGG) surgery has evolved around the principal belief that a safe maximal tumor resection improves symptoms, quality of life, and survival. Mapping brain function has been recently improved by resting state functional magnetic resonance imaging (rest-fMRI), a novel imaging technique that explores networks connectivity at "rest".
METHODS: This prospective study analyzed 10 patients with HGG in whom rest-fMRI connectivity was assessed both in single-subject and in group analysis before and after surgery. Seed-based functional connectivity analysis was performed with CONN toolbox. Network identification focused on 8 major functional connectivity networks. A voxel-wise ROI to ROI correlation maps to assess functional connectivity throughout the whole brain was computed from a priori seeds ROI in specific RSNs before and after surgical resection in each patient.
RESULTS: Reliable topography of all 8 RSNs were successfully identified in each participant before surgical resection. Single-subject functional connectivity analysis showed functional disconnection for dorsal attention and salience networks, whereas the language network demonstrated functional connection either in the case of left temporal glioblastoma. Functional connectivity in group analysis showed wide variations of functional connectivity in the default mode, salience, and sensorimotor networks. However, salience and language networks, salience and default mode networks, and salience and sensorimotor networks showed a significant correlation (p-uncorrected < 0.0025; p-FDR < 0.077) in comparison before and after surgery confirming non-disconnection of these networks.
CONCLUSIONS: Resting-state fMRI can reliably detect common functional connectivity networks in patients with glioma and has the potential to anticipate network alterations after surgical resection.

PMID: 32428723 [PubMed - as supplied by publisher]

Functional network analysis of the sub-regions of the primary motor cortex during rest.

Wed, 05/20/2020 - 18:00

Functional network analysis of the sub-regions of the primary motor cortex during rest.

Neuroreport. 2020 Jun 07;31(9):691-695

Authors: Alahmadi AAS

Abstract
The cytoarchitectonic properties of the primary motor cortex have shown two distinct sub-regions: Anterior Broadmann area 4 (BA4a) and Posterior Broadmann area 4 (BA4p). Some previous studies have suggested that these two sub-regions are functionally different and showed that in few fMRI experiments, these sub-regions may have different roles in brain functions. Resting-state fMRI (rsfMRI) is advanced technique that allows investigating in detail the functional connectivity and provides a greater understanding of the physiological behavior of different brain regions. In this study, 198 healthy subjects were examined using a region-based rsfMRI analysis to investigate whether BA4a and BA4p have similar or different connections to other brain networks. The finding shows that indeed these two sub-regions have distinct connectivity to different brain networks. BA4a has a greater connection to motor-related areas while BA4p has connections to nonmotor-related areas (such as sensory, attentional, and higher order regions), suggesting that these two sub-regions should be considered as two separate regions of interests.

PMID: 32427715 [PubMed - in process]

Similar and Different Regional Homogeneity Changes Between Bipolar Disorder and Unipolar Depression: A Resting-State fMRI Study.

Wed, 05/20/2020 - 18:00

Similar and Different Regional Homogeneity Changes Between Bipolar Disorder and Unipolar Depression: A Resting-State fMRI Study.

Neuropsychiatr Dis Treat. 2020;16:1087-1093

Authors: Liu P, Li Q, Zhang A, Liu Z, Sun N, Yang C, Wang Y, Zhang K

Abstract
Objective: To investigate the regional homogeneity (ReHo) between unipolar depression (UD) and bipolar disorder (BD), and to search for brain imaging markers for distinguishing UD and BD.
Methods: A total of 58 patients who met the diagnosis criteria of UD in DSM-Ⅳ, 40 patients who met the diagnosis criteria of BD in DSM-Ⅳ and 54 healthy controls (HC) completed the resting-state functional magnetic resonance (rs-fMRI) scans. The ReHo of the three groups was compared and Pearson correlation analysis was performed between the ReHo values and the clinical symptoms.
Results: (1) Significant differences were found in the right hippocampus, right parahippocampal gyrus, right Inferior orbitofrontal gyrus, right superior temporal gyrus, right inferior temporal gyrus, and right middle occipital gyrus across the three groups. (2) Compared to HC, the ReHo in the right parahippocampal gyrus in UD significantly increased. (3) When compared to HC, the ReHo in the right hippocampus in BD significantly increased. The ReHo in the right middle occipital gyrus decreased. (4) Compared to UD, BD exhibited significantly decreased ReHo in the right inferior temporal gyrus. No correlations were observed between the scores of 24-item Hamilton Depression Rating Scale (HDMD-24), Hamilton Anxiety Scale (HAMA), Young Mania Rating Scale (YMRS), and the ReHo values of altered brain regions between BD and UD.
Conclusion: The results suggest that there was a considerable difference in the ReHo of brain among UD, BD, and HCs. ReHo in the right inferior temporal gyrus showed significant differences between BD and UD that might serve as neuroimaging markers to identify BD and UD.

PMID: 32425537 [PubMed]

Detection of muscle activity with forearm pronation exercise using T2-map MRI.

Wed, 05/20/2020 - 18:00

Detection of muscle activity with forearm pronation exercise using T2-map MRI.

J Phys Ther Sci. 2020 May;32(5):337-341

Authors: Takamori M, Akiyama S, Ogata H, Yokoi-Hayakawa M, Imaizumi-Ohashi Y, Seo Y, Mizushima T

Abstract
[Purpose] We aimed to detect muscle activity during a forearm pronation exercise using a 0.2 T MRI system. [Participants and Methods] We recruited healthy adult volunteers (7 males, 4 females). Transverse relaxation time (T2) values for 10 forearm muscles were obtained from transverse multiple-spin-echo MR images of one-third of the ulna, lengthwise from the olecranon, in the resting state and after isotonic forearm pronation exercise at three strength levels (5, 15, and 25% of the maximum voluntary contraction). Z values were calculated as (T2e - T2r)/SDr, where T2e, T2r and SDr were T2 after exercise, 34 ms, and 3 ms, respectively. A Z value of 2.56 was used as the threshold for defining muscle activation. [Results] T2 values increased significantly in the pronator teres muscle (agonist), while those in the supinator muscle (antagonist) showed no change. The sensitivity and specificity values obtained were high and low, respectively, for all of the three exercise strength levels employed. In some of the participants, activity was detected in the flexor carpi radialis, extensor carpi ulnaris, and extensor digitorum. [Conclusion] Using T2-map MRI, we detected activity in primary and secondary mover muscles. We also found individual variations in the use of forearm muscles during pronation.

PMID: 32425351 [PubMed]

Abnormal functional connectivity and effective connectivity between the default mode network and attention networks in patients with alcohol-use disorder.

Wed, 05/20/2020 - 18:00
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Abnormal functional connectivity and effective connectivity between the default mode network and attention networks in patients with alcohol-use disorder.

Acta Radiol. 2020 May 18;:284185120923270

Authors: Song Z, Chen J, Wen Z, Zhang L

Abstract
BACKGROUND: Patients with alcohol-use disorder (AUD) demonstrate dysfunctional cerebral network connectivity. However, limited studies have investigated attention systems in AUD.
PURPOSE: To assess functional (FC) and effective connectivity (EC) in the dorsal (DAN) and ventral attention networks (VAN) and default mode network (DMN) in patients with AUD using resting-state functional magnetic resonance imaging (rs-fMRI).
MATERIAL AND METHODS: MRI and rs-fMRI data were obtained from 28 men with AUD and 30 age-matched healthy controls. Independent component analysis was used to identify and extract network data, for comparison between the two groups. Effective connectivity was evaluated using Granger causality analysis (GCA) by selecting significantly different brain areas as regions of interest (ROI). Signed-path coefficients between ROIs were computed in bivariate mode.
RESULTS: In patients with AUD, FC decreased in the left superior parietal gurus (SPG) and left interparietal sulcus (IPS, in DAN); FC decreased in the right superior frontal gyrus (SPG) and right middle frontal gyrus (MFG, in DMN). GCA values indicated that the DMN exerts a positive causal effect on the DAN (P = 0.007/0.027), which consequently exerts a negative causal effect on the DMN (P = 0.032). Signed-path coefficients from the right MFG to the left IPS correlated negatively with MAST scores (P = 0.015).
CONCLUSION: We found novel inter-network connectivity dysfunction in patients with AUD, which indicates abnormal causal relations between resting-state DAN and DMN. Thus, patients with AUD may have abnormal top-down attention modulation and cognition.

PMID: 32423229 [PubMed - as supplied by publisher]

The Amygdala in Schizophrenia and Bipolar Disorder: A Synthesis of Structural MRI, Diffusion Tensor Imaging, and Resting-State Functional Connectivity Findings.

Wed, 05/20/2020 - 18:00
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The Amygdala in Schizophrenia and Bipolar Disorder: A Synthesis of Structural MRI, Diffusion Tensor Imaging, and Resting-State Functional Connectivity Findings.

Harv Rev Psychiatry. 2019 May/Jun;27(3):150-164

Authors: Ho NF, Li Hui Chong P, Lee DR, Chew QH, Chen G, Sim K

Abstract
Frequently implicated in psychotic spectrum disorders, the amygdala serves as an important hub for elucidating the convergent and divergent neural substrates in schizophrenia and bipolar disorder, the two most studied groups of psychotic spectrum conditions. A systematic search of electronic databases through December 2017 was conducted to identify neuroimaging studies of the amygdala in schizophrenia and bipolar disorder, focusing on structural MRI, diffusion tensor imaging (DTI), and resting-state functional connectivity studies, with an emphasis on cross-diagnostic studies. Ninety-four independent studies were selected for the present review (49 structural MRI, 27 DTI, and 18 resting-state functional MRI studies). Also selected, and analyzed in a separate meta-analysis, were 33 volumetric studies with the amygdala as the region-of-interest. Reduced left, right, and total amygdala volumes were found in schizophrenia, relative to both healthy controls and bipolar subjects, even when restricted to cohorts in the early stages of illness. No volume abnormalities were observed in bipolar subjects relative to healthy controls. Shape morphometry studies showed either amygdala deformity or no differences in schizophrenia, and no abnormalities in bipolar disorder. In contrast to the volumetric findings, DTI studies of the uncinate fasciculus tract (connecting the amygdala with the medial- and orbitofrontal cortices) largely showed reduced fractional anisotropy (a marker of white matter microstructure abnormality) in both schizophrenia and bipolar patients, with no cross-diagnostic differences. While decreased amygdalar-orbitofrontal functional connectivity was generally observed in schizophrenia, varying patterns of amygdalar-orbitofrontal connectivity in bipolar disorder were found. Future studies can consider adopting longitudinal approaches with multimodal imaging and more extensive clinical subtyping to probe amygdalar subregional changes and their relationship to the sequelae of psychotic disorders.

PMID: 31082993 [PubMed - indexed for MEDLINE]

Error-related Persistence of Motor Activity in Resting-state Networks.

Wed, 05/20/2020 - 18:00
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Error-related Persistence of Motor Activity in Resting-state Networks.

J Cogn Neurosci. 2018 12;30(12):1883-1901

Authors: Bernardi NF, Van Vugt FT, Valle-Mena RR, Vahdat S, Ostry DJ

Abstract
The relationship between neural activation during movement training and the plastic changes that survive beyond movement execution is not well understood. Here we ask whether the changes in resting-state functional connectivity observed following motor learning overlap with the brain networks that track movement error during training. Human participants learned to trace an arched trajectory using a computer mouse in an MRI scanner. Motor performance was quantified on each trial as the maximum distance from the prescribed arc. During learning, two brain networks were observed, one showing increased activations for larger movement error, comprising the cerebellum, parietal, visual, somatosensory, and cortical motor areas, and the other being more activated for movements with lower error, comprising the ventral putamen and the OFC. After learning, changes in brain connectivity at rest were found predominantly in areas that had shown increased activation for larger error during task, specifically the cerebellum and its connections with motor, visual, and somatosensory cortex. The findings indicate that, although both errors and accurate movements are important during the active stage of motor learning, the changes in brain activity observed at rest primarily reflect networks that process errors. This suggests that error-related networks are represented in the initial stages of motor memory formation.

PMID: 30125221 [PubMed - indexed for MEDLINE]

Fast detection and reduction of local transient artifacts in resting-state fMRI.

Tue, 05/19/2020 - 17:00
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Fast detection and reduction of local transient artifacts in resting-state fMRI.

Comput Biol Med. 2020 May;120:103742

Authors: Jo HJ, Reynolds RC, Gotts SJ, Handwerker DA, Balzekas I, Martin A, Cox RW, Bandettini PA

Abstract
Image quality control (QC) is a critical and computationally intensive component of functional magnetic resonance imaging (fMRI). Artifacts caused by physiologic signals or hardware malfunctions are usually identified and removed during data processing offline, well after scanning sessions are complete. A system with the computational efficiency to identify and remove artifacts during image acquisition would permit rapid adjustment of protocols as issues arise during experiments. To improve the speed and accuracy of QC and functional image correction, we developed Fast Anatomy-Based Image Correction (Fast ANATICOR) with newly implemented nuisance models and an improved pipeline. We validated its performance on a dataset consisting of normal scans and scans containing known hardware-driven artifacts. Fast ANATICOR's increased processing speed may make real-time QC and image correction feasible as compared with the existing offline method.

PMID: 32421647 [PubMed - as supplied by publisher]

Impacts of FKBP5 variants on large-scale brain network connectivity in healthy adults.

Tue, 05/19/2020 - 17:00
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Impacts of FKBP5 variants on large-scale brain network connectivity in healthy adults.

J Affect Disord. 2020 May 14;273:32-40

Authors: Zhang H, Wang YF, Zheng LJ, Lin L, Zhang XY, Yang YT, Liu Y, Lu GM, Zhang LJ

Abstract
BACKGROUND: FK506 binding protein 5 (FKBP5) rs1360780 polymorphism has been identified as a molecular genetic marker associated with the dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis. The impact of FKBP5 rs1360780 on the large-scale brain network connectivity in healthy adults is still unknown.
METHODS: 479 healthy volunteers (age: 20-80years) completed MRI scans, neuropsychological assessments and blood analysis.All subjects were divided into CC, CT and TT genotypes. Within and between network connectivities (10 sub-networks) were calculated using resting state functional MRI (rs-fMRI) data. The genetic effects and gene-gender/age interaction on large-scale network connectivity were explored.
RESULTS: Compared with CC and CT groups, TT group showed increased intra-connectivity in default mode network (DMN) and increased inter-connectivity mainly distributed among the network of DMN, salience network (SAN), dorsal attention network (DAN), ventral attention network (VAN), subcortical network (SUB), and visual network (VIS). Gene-by-gender and gene-by-age interaction were found in inter-connectivity of DAN to VIS and DMN to FPN, respectively. The altered connectivities correlated with anxiety status test score.
LIMITATIONS: Plasma adrenocorticotropic hormone (ACTH) or cortisol were not measured,or else, we could estimate the hypothalamic-pituitary-adrenal (HPA) axis activity which may strengthen our results.
CONCLUSIONS: FKBP5 rs1360780 modulates the large-scale brain network connectivity in healthy adults. TT carriers showed the increased intra- and inter-connectivities mainly distributed among the network of DMN, SAN, DAN, VAN, SUB and VIS.

PMID: 32421620 [PubMed - as supplied by publisher]

Women with Major Depressive Disorder, Irrespective of Comorbid Anxiety Disorders, Show Blunted Bilateral Frontal Responses during Win and Loss Anticipation.

Tue, 05/19/2020 - 17:00
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Women with Major Depressive Disorder, Irrespective of Comorbid Anxiety Disorders, Show Blunted Bilateral Frontal Responses during Win and Loss Anticipation.

J Affect Disord. 2020 May 11;273:157-166

Authors: Stewart JL, White EJ, Kuplicki R, Akeman E, Bodurka J, Cha YH, Feinstein JS, Khalsa SS, Savitz JA, Victor TA, Paulus MP, Aupperle RL

Abstract
BACKGROUND: Electroencephalography (EEG) studies suggest that major depressive disorder (MDD) is associated with lower left than right frontal brain activity (asymmetry), a pattern appearing stronger in women than men, and when elicited during emotionally-relevant paradigms versus an uncontrolled resting state. However, it is unclear whether this asymmetry pattern generalizes to the common presentation of MDD with co-occurring anxiety. Moreover, asymmetry may differ for anxiety subtypes, wherein anxious apprehension (AnxApp: worry characteristic of generalized anxiety disorder) appears left-lateralized, but anxious arousal (AnxAro: panic characteristic of social anxiety, posttraumatic stress, and panic disorders) may be right-lateralized.
METHODS: This analysis attempted to replicate frontal EEG asymmetry patterns using functional magnetic resonance imaging (fMRI). Participants completed clinical interviews and a monetary incentive delay (MID) task during fMRI recording. We compared five groups of right-handed women from the Tulsa 1000 study, MDD (n=40), MDD-AnxApp (n=26), MDD-AnxAro (n=34), MDD-Both (with AnxApp and AnxAro; n=26), and healthy controls (CTL; n=24), as a function of MID anticipation condition (no win/loss, win, loss) and hemisphere on frontal blood oxygen-level-dependent (BOLD) signal.
RESULTS: CTL exhibited higher bilateral superior, middle, and inferior middle frontal gyrus BOLD signal than the four MDD groups for high arousal (win and loss) conditions. However, frontal attenuations were unrelated to current depression/anxiety symptoms, suggestive of a trait as opposed to a state marker.
LIMITATIONS: This was a cross-sectional analysis restricted to women.
CONCLUSIONS: Reduced prefrontal cortex recruitment during processing of both positively and negatively valenced stimuli is consistent with the emotion context insensitivity theory of MDD.

PMID: 32421596 [PubMed - as supplied by publisher]

Locations for noninvasive brain stimulation in treating depressive disorders: A combination of meta-analysis and resting-state functional connectivity analysis.

Tue, 05/19/2020 - 17:00
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Locations for noninvasive brain stimulation in treating depressive disorders: A combination of meta-analysis and resting-state functional connectivity analysis.

Aust N Z J Psychiatry. 2020 May 18;:4867420920372

Authors: Zhang B, Liu J, Bao T, Wilson G, Park J, Zhao B, Kong J

Abstract
OBJECTIVE: Many noninvasive brain stimulation techniques have been applied to treat depressive disorders. However, the target brain region in most noninvasive brain stimulation studies is the dorsolateral prefrontal cortex. Exploring new stimulation locations may improve the efficacy of noninvasive brain stimulation for depressive disorders. We aimed to explore potential noninvasive brain stimulation locations for depressive disorders through a meta-analysis and a functional connectivity approach.
METHODS: We conducted a meta-analysis of 395 functional magnetic resonance imaging studies to identify depressive disorder-associated brain regions as regions of interest. Then, we ran resting-state functional connectivity analysis with three different pipelines in 40 depression patients to find brain surface regions correlated with these regions of interest. The 10-20 system coordinates corresponding to these brain surface regions were considered as potential locations for noninvasive brain stimulation.
RESULTS: The 10-20 system coordinates corresponding to the bilateral dorsolateral prefrontal cortex, bilateral inferior frontal gyrus, medial prefrontal cortex, supplementary motor area, bilateral supramarginal gyrus, bilateral primary motor cortex, bilateral operculum, left angular gyrus and right middle temporal gyrus were identified as potential locations for noninvasive brain stimulation in depressive disorders. The coordinates were: posterior to F3, posterior to F4, superior to F3, posterior to F7, anterior to C4, P3, midpoint of F7-T3, posterior to F8, anterior to C3, midpoint of Fz-Cz, midpoint of Fz-Fp1, anterior to T4, midpoint of C3-P3, and anterior to C4.
CONCLUSION: Our study identified several potential noninvasive brain stimulation locations for depressive disorders, which may serve as a basis for future clinical investigations.

PMID: 32419470 [PubMed - as supplied by publisher]

Altered spontaneous activity and effective connectivity of the anterior cingulate cortex in obsessive-compulsive disorder.

Tue, 05/19/2020 - 17:00
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Altered spontaneous activity and effective connectivity of the anterior cingulate cortex in obsessive-compulsive disorder.

J Comp Neurol. 2020 May 18;:

Authors: Long J, Luo L, Guo Y, You W, Li Q, Li B, Tang W, Yang Y, Kemp GJ, Sweeney JA, Li F, Gong Q

Abstract
Obsessive-compulsive disorder (OCD) is a disabling neuropsychiatric disorder whose neurobiological basis remains unclear. Magnetic resonance imaging (MRI) studies have reported functional and structural alterations of the anterior cingulate cortex (ACC) in OCD. In this study, we explored the functional activity of subregions of the ACC and effective connectivity (EC) between ACC subregions and the whole brain in OCD. We used a Granger causality analysis (GCA) to identify the direction of information flow and whether the impact of that flow was excitatory or inhibitory. We performed resting-state functional MRI in 31 patients with OCD and 36 healthy controls, and analyzed the amplitude of low-frequency fluctuation (ALFF) and coefficient-based GCA. The left pregenual ACC (pACC) in patients with OCD showed decreased ALFF relative to controls. There was significantly decreased excitatory output from the left pACC to both right dorsal superior frontal gyrus (dSFG) and left precuneus in patients compared with controls. Patients also had decreased inhibitory input to left pACC from left ventral SFG and left thalamus and caudate relative to controls. Results were similar in drug naive patients and those with prior but not current psychopharmacological treatment. In patients, path coefficients of GCA from left pACC to right dSFG showed significant negative correlations with obsession and anxiety ratings. Decreased spontaneous neural activity and altered EC of pACC with widely distributed cortical circuitry, and associations with clinical ratings highlight the importance of pACC functional alteration in OCD. This article is protected by copyright. All rights reserved.

PMID: 32419131 [PubMed - as supplied by publisher]

EEG evidence of compensatory mechanisms in preclinical Alzheimer's disease.

Tue, 05/19/2020 - 17:00
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EEG evidence of compensatory mechanisms in preclinical Alzheimer's disease.

Brain. 2019 07 01;142(7):2096-2112

Authors: Gaubert S, Raimondo F, Houot M, Corsi MC, Naccache L, Diego Sitt J, Hermann B, Oudiette D, Gagliardi G, Habert MO, Dubois B, De Vico Fallani F, Bakardjian H, Epelbaum S, Alzheimer’s Disease Neuroimaging Initiative

Abstract
Early biomarkers are needed to identify individuals at high risk of preclinical Alzheimer's disease and to better understand the pathophysiological processes of disease progression. Preclinical Alzheimer's disease EEG changes would be non-invasive and cheap screening tools and could also help to predict future progression to clinical Alzheimer's disease. However, the impact of amyloid-β deposition and neurodegeneration on EEG biomarkers needs to be elucidated. We included participants from the INSIGHT-preAD cohort, which is an ongoing single-centre multimodal observational study that was designed to identify risk factors and markers of progression to clinical Alzheimer's disease in 318 cognitively normal individuals aged 70-85 years with a subjective memory complaint. We divided the subjects into four groups, according to their amyloid status (based on 18F-florbetapir PET) and neurodegeneration status (evidenced by 18F-fluorodeoxyglucose PET brain metabolism in Alzheimer's disease signature regions). The first group was amyloid-positive and neurodegeneration-positive, which corresponds to stage 2 of preclinical Alzheimer's disease. The second group was amyloid-positive and neurodegeneration-negative, which corresponds to stage 1 of preclinical Alzheimer's disease. The third group was amyloid-negative and neurodegeneration-positive, which corresponds to 'suspected non-Alzheimer's pathophysiology'. The last group was the control group, defined by amyloid-negative and neurodegeneration-negative subjects. We analysed 314 baseline 256-channel high-density eyes closed 1-min resting state EEG recordings. EEG biomarkers included spectral measures, algorithmic complexity and functional connectivity assessed with a novel information-theoretic measure, weighted symbolic mutual information. The most prominent effects of neurodegeneration on EEG metrics were localized in frontocentral regions with an increase in high frequency oscillations (higher beta and gamma power) and a decrease in low frequency oscillations (lower delta power), higher spectral entropy, higher complexity and increased functional connectivity measured by weighted symbolic mutual information in theta band. Neurodegeneration was associated with a widespread increase of median spectral frequency. We found a non-linear relationship between amyloid burden and EEG metrics in neurodegeneration-positive subjects, either following a U-shape curve for delta power or an inverted U-shape curve for the other metrics, meaning that EEG patterns are modulated differently depending on the degree of amyloid burden. This finding suggests initial compensatory mechanisms that are overwhelmed for the highest amyloid load. Together, these results indicate that EEG metrics are useful biomarkers for the preclinical stage of Alzheimer's disease.

PMID: 31211359 [PubMed - indexed for MEDLINE]

Altered functional connectivity of the posterior cingulate cortex in type 2 diabetes with cognitive impairment.

Tue, 05/19/2020 - 17:00
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Altered functional connectivity of the posterior cingulate cortex in type 2 diabetes with cognitive impairment.

Brain Imaging Behav. 2019 Dec;13(6):1699-1707

Authors: Tan X, Liang Y, Zeng H, Qin C, Li Y, Yang J, Qiu S

Abstract
The posterior cingulate cortex (PCC) has been suggested to be a cortical hub of the default mode network (DMN). Our goal in the current study was to determine whether there were alterations in the PCC's functional connectivity (FC) with whole brain regions in type 2 diabetes mellitus (T2DM) and to determine their relationships with cognitive dysfunction. In this study, the FC of the PCC was characterized by using resting-state functional MRI and a seed-based whole-brain correlation method in 24 T2DM patients and compared with 24 well-matched healthy controls. Spearman correlation analysis was performed to determine the relationships between the FC of the PCC and cognitive dysfunction. T2DM was associated with a significantly decreased FC of the PCC to widespread brain regions (p < 0.05, corrected for AlphaSim). We also found that the FC of the PCC in these brain regions was positively correlated with several neuropsychological test scores, such as the FC to the right angular gyrus (AnG) and the bilateral middle temporal gyrus (MTG) with the Auditory Verbal Learning Test (AVLT) and the FC to the bilateral inferior frontal gyrus (IFG) with the digit span test (DST). Moreover, the FCs of the PCC to the right superior parietal lobule (SPL), bilateral temporal lobes and left cerebrum were detected as negatively correlated with the Trail Making Test (TMT). No such correlations were detected in healthy controls. The present study provides useful information about the effect of the FC of the PCC on the underlying neuropathological process of T2DM-related cognitive dysfunction and may provide supporting evidence for further molecular biology studies.

PMID: 30612339 [PubMed - indexed for MEDLINE]

Machine learning approach to identify a resting-state functional connectivity pattern serving as an endophenotype of autism spectrum disorder.

Tue, 05/19/2020 - 17:00
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Machine learning approach to identify a resting-state functional connectivity pattern serving as an endophenotype of autism spectrum disorder.

Brain Imaging Behav. 2019 Dec;13(6):1689-1698

Authors: Yamagata B, Itahashi T, Fujino J, Ohta H, Nakamura M, Kato N, Mimura M, Hashimoto RI, Aoki Y

Abstract
Endophenotype refers to a measurable and heritable component between genetics and diagnosis, and the same endophenotype is present in both individuals with a diagnosis and their unaffected siblings. Determination of the neural correlates of an endophenotype and diagnosis is important in autism spectrum disorder (ASD). However, prior studies enrolling individuals with ASD and their unaffected siblings have generally included only one group of typically developing (TD) subjects; they have not accounted for differences between TD siblings. Thus, they could not differentiate the neural correlates for endophenotype from the clinical diagnosis. In this context, we enrolled pairs of siblings with an ASD endophenotype (individuals with ASD and their unaffected siblings) and pairs of siblings without this endophenotype (pairs of TD siblings). Using resting-state functional MRI, we first aimed to identify an endophenotype pattern consisting of multiple functional connections (FCs) then examined the neural correlates of FCs for ASD diagnosis, controlling for differences between TD siblings. Sparse logistic regression successfully classified subjects as to the endophenotype (area under the curve = 0.78, classification accuracy = 75%). Then, a bootstrapping approach controlling for differences between TD siblings revealed that an FC between the right middle temporal gyrus and right anterior cingulate cortex was substantially different between individuals with ASD and their unaffected siblings, suggesting that this FC may be a neural correlate for the diagnosis, while the other FCs represent the endophenotype. The current findings suggest that an ASD endophenotype pattern exists in FCs, and a neural correlate for ASD diagnosis is dissociable from this endophenotype. (250 words).

PMID: 30280304 [PubMed - indexed for MEDLINE]

Diminished self-monitoring in hallucinations - Aberrant anterior insula connectivity differentiates auditory hallucinations in schizophrenia from subjective tinnitus.

Mon, 05/18/2020 - 16:20
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Diminished self-monitoring in hallucinations - Aberrant anterior insula connectivity differentiates auditory hallucinations in schizophrenia from subjective tinnitus.

Asian J Psychiatr. 2020 May 07;52:102056

Authors: Yang H, Wang M, Wu F, Li Q, Zheng Y, Qin P

Abstract
Auditory hallucinations in schizophrenia (SCZ-AH) and subjective tinnitus (TN) are two conditions that share a superficial resemblance, namely the presence of phantom sounds produced by the brain. A crucial difference between them lies in the self-processing of the phantom signals, which is intact in TN patients but lost in SCZ-AH. Our study sets out to investigate the potential neural mechanisms for this crucial psychotic symptom of SCZ-AH under the framework of self. We gathered resting-state fMRI data from three participant groups: SCZ-AH, TN and healthy controls. Focusing on predefined self-related regions-of-interest, we found that SCZ-AH had reduced degree centrality in the right anterior insula (rAI) compared to both TN and healthy controls. Further functional connectivity analysis showed a reduced connectivity between the rAI and right superior temporal gyrus. Our finding indicates that compromised self-processing in SCZ-AH could be due to aberrant connectivity in rAI, which interacted with the decreased connectivity between rAI and auditory cortex, and jointly contributed to the misattribution of the source of the phantom sound. Our findings provided preliminary evidence for the neural mechanism of self-disorder underlying SCZ-AH, and could provide implications for investigating other modalities of hallucinations in schizophrenia.

PMID: 32417745 [PubMed - as supplied by publisher]

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