Most recent paper

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

Thu, 01/14/2021 - 21:50
Related Articles

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
Related Articles

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
Related Articles

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
Related Articles

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
Related Articles

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
Related Articles

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
Related Articles

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
Related Articles

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
Related Articles

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]

Neural Correlates of Cognitive Dysfunctions in Cervical Spondylotic Myelopathy Patients: A Resting-State fMRI Study.

Wed, 01/13/2021 - 00:49
Related Articles

Neural Correlates of Cognitive Dysfunctions in Cervical Spondylotic Myelopathy Patients: A Resting-State fMRI Study.

Front Neurol. 2020;11:596795

Authors: Zhao R, Su Q, Chen Z, Sun H, Liang M, Xue Y

Abstract
Cervical spondylotic myelopathy (CSM) is a common disease of the elderly that is characterized by gait instability, sensorimotor deficits, etc. Recurrent symptoms including memory loss, poor attention, etc. have also been reported in recent studies. However, these have been rarely investigated in CSM patients. To investigate the cognitive deficits and their correlation with brain functional alterations, we conducted resting-state fMRI (rs-fMRI) signal variability. This is a novel indicator in the neuroimaging field for assessing the regional neural activity in CSM patients. Further, to explore the network changes in patients, functional connectivity (FC) and graph theory analyses were performed. Compared with the controls, the signal variabilities were significantly lower in the widespread brain regions especially at the default mode network (DMN), visual network, and somatosensory network. The altered inferior parietal lobule signal variability positively correlated with the cognitive function level. Moreover, the FC and the global efficiency of DMN increased in patients with CSM and positively correlated with the cognitive function level. According to the study results, (1) the cervical spondylotic myelopathy patients exhibited regional neural impairments, which correlated with the severity of cognitive deficits in the DMN brain regions, and (2) the increased FC and global efficiency of DMN can compensate for the regional impairment.

PMID: 33424749 [PubMed]

Altered Local Gyrification Index and Corresponding Functional Connectivity in Medication Free Major Depressive Disorder.

Wed, 01/13/2021 - 00:49
Related Articles

Altered Local Gyrification Index and Corresponding Functional Connectivity in Medication Free Major Depressive Disorder.

Front Psychiatry. 2020;11:585401

Authors: Long J, Xu J, Wang X, Li J, Rao S, Wu H, Kuang W

Abstract
A lot of previous studies have documented that major depressive disorder (MDD) is a developmental disorder. The cortical surface measure, local gyrification index (LGI), can well reflect the fetal and early postnatal neurodevelopmental processes. Thus, LGI may provide new insight for the neuropathology of MDD. The previous studies only focused on the surface structural abnormality, but how the structural abnormality lead to functional connectivity changes is unexplored. In this study, we investigated LGI and corresponding functional connectivity difference in 28 medication-free MDD patients. We found significantly decreased LGI in left lingual gyrus (LING) and right posterior superior temporal sulcus (bSTS), and the changed LGI in bSTS was negatively correlated with disease onset age and anxiety scores. The following functional connectivity analyses identified decreased functional connectivities between LING and right LING, precentral gyrus, and middle temporal gyrus. The decreased functional connectivities were correlated with disease duration, onset, and depression symptoms. Our findings revealed abnormal LGI in LING and bSTS indicating that the abnormal developmental of visual and social cognition related brain areas may be an early biomarker for depression.

PMID: 33424661 [PubMed]

Salience, emotion, and attention: the neural networks underlying tinnitus distress revealed using music and rest.

Tue, 01/12/2021 - 00:48
Related Articles

Salience, emotion, and attention: the neural networks underlying tinnitus distress revealed using music and rest.

Brain Res. 2021 Jan 07;:147277

Authors: Shahsavarani S, Schmidt SA, Khan RA, Tai Y, Husain FT

Abstract
In the present study, we used an innovative music-rest interleaved fMRI paradigm to investigate the neural correlates of tinnitus distress. Tinnitus is a poorly-understood hearing disorder where individuals perceive sounds, in the absence of an external source. Although the great majority of individuals habituate to chronic tinnitus and report few symptoms, a minority report debilitating distress and annoyance. Prior research suggests that a diverse set of brain regions, including the attention, the salience, and the limbic networks, play key roles in mediating both the perception of tinnitus and its impact on the individual; however, evidence of the degree and extent of their involvement has been inconsistent. Here, we minimally modified the conventional resting state fMRI by interleaving it with segments of jazz music. We found that the functional connectivity between a set of brain regions-including cerebellum, precuneus, superior/middle frontal gyrus, and primary visual cortex-and seeds in the dorsal attention network, the salience network, and the amygdala, were effective in fractionating the tinnitus patients into two subgroups, characterized by the severity of tinnitus-related distress. Further, our findings revealed cross-modal modulation of the attention and salience networks by the visual modality during the music segments. On average, the more bothersome the reported tinnitus, the stronger was the exhibited inter-network functional connectivity. This study substantiates the essential role of the attention, salience, and limbic networks in tinnitus habituation, and suggests modulation of the attention and salience networks across the auditory and visual modalities as a possible compensatory mechanism for bothersome tinnitus.

PMID: 33422540 [PubMed - as supplied by publisher]

Acute effects of alcohol on resting-state functional connectivity in healthy young men.

Mon, 01/11/2021 - 00:48
Related Articles

Acute effects of alcohol on resting-state functional connectivity in healthy young men.

Addict Behav. 2020 Dec 16;115:106786

Authors: Han J, Keedy S, Murray CH, Foxley S, de Wit H

Abstract
Alcohol abuse and dependence remain significant public health issues, and yet the brain circuits that are involved in the rewarding effects of alcohol are poorly understood. One promising way to study the effects of alcohol on neural activity is to examine its effects on functional connectivity between brain areas involved in reward and other functions. Here, we compared the effects of two doses of alcohol (0.4 and 0.8 g/kg) to placebo on resting-state functional connectivity in brain circuits related to reward in 19 healthy young men without histories of alcohol problems. The higher, but not the lower, dose of alcohol, significantly increased connectivity from reward-related regions to sensory and motor cortex, and between seeds associated with cognitive control. Contrary to expectation, alcohol did not significantly change connectivity for the ventral striatum at either dose. These findings reveal unrecognized effects of alcohol on connectivity from reward-related regions to visual and sensory cortical areas.

PMID: 33421747 [PubMed - as supplied by publisher]

Longitudinal changes in network homogeneity in presymptomatic C9orf72 mutation carriers.

Mon, 01/11/2021 - 00:48
Related Articles

Longitudinal changes in network homogeneity in presymptomatic C9orf72 mutation carriers.

Neurobiol Aging. 2020 Dec 08;99:1-10

Authors: Waugh RE, Danielian LE, Shoukry RFS, Floeter MK

Abstract
The risk for carriers of repeat expansion mutations in C9orf72 to develop amyotrophic lateral sclerosis and frontotemporal dementia increases with age. Functional magnetic resonance imaging studies have shown reduced connectivity in symptomatic carriers, but it is not known whether connectivity declines throughout life as an acceleration of the normal aging pattern. In this study, we examined intra-network homogeneity (NeHo) in 5 functional networks in 15 presymptomatic C9+ carriers over an 18-month period and compared to repeated scans in 34 healthy controls and 27 symptomatic C9+ carriers. The longitudinal trajectory of NeHo in the somatomotor, dorsal attention, and default mode networks in presymptomatic carriers differed from aging controls and symptomatic carriers. In somatomotor networks, NeHo increased over time in regions adjacent to regions where symptomatic carriers had reduced NeHo. In the default network, the posterior cingulate exhibited age-dependent increases in NeHo. These findings are evidence against the proposal that the decline in functional connectivity seen in symptomatic carriers represents a lifelong acceleration of the healthy aging process.

PMID: 33421737 [PubMed - as supplied by publisher]

Behavioural relevance of spontaneous, transient brain network interactions in fMRI.

Mon, 01/11/2021 - 00:48
Related Articles

Behavioural relevance of spontaneous, transient brain network interactions in fMRI.

Neuroimage. 2021 Jan 06;:117713

Authors: Vidaurre D, Llera A, Smith SM, Woolrich MW

Abstract
How spontaneously fluctuating functional magnetic resonance imaging (fMRI) signals in different brain regions relate to behaviour has been an open question for decades. Correlations in these signals, known as functional connectivity, can be averaged over several minutes of data to provide a stable representation of the functional network architecture for an individual. However, associations between these stable features and behavioural traits have been shown to be dominated by individual differences in anatomy. Here, using kernel learning tools, we propose methods to assess and compare the relation between time-varying functional connectivity, time-averaged functional connectivity, structural brain data, and non-imaging subject behavioural traits. We applied these methods to Human Connectome Project resting-state fMRI data to show that time-varying fMRI functional connectivity, detected at time-scales of a few seconds, has associations with some behavioural traits that are not dominated by anatomy. Despite time-averaged functional connectivity accounting for the largest proportion of variability in the fMRI signal between individuals, we found that some aspects of intelligence could only be explained by time-varying functional connectivity. The finding that time-varying fMRI functional connectivity has a unique relationship to population behavioural variability suggests that it might reflect transient neuronal communication fluctuating around a stable neural architecture.

PMID: 33421594 [PubMed - as supplied by publisher]

Resting-State Functional Connectivity and Brain Network Abnormalities in Depressive Patients with Suicidal Ideation.

Mon, 01/11/2021 - 00:48
Related Articles

Resting-State Functional Connectivity and Brain Network Abnormalities in Depressive Patients with Suicidal Ideation.

Brain Topogr. 2021 Jan 08;:

Authors: Chen VC, Chou YS, Tsai YH, Huang YC, McIntyre RS, Weng JC

Abstract
Our study aimed to investigate whether changes in brain function measured with functional magnetic resonance imaging (fMRI) can be detected among individuals with depressive disorders and suicidal ideation. The association between depression severity and brain images is also discussed. Our study recruited 111 participants in three groups: 35 depressive patients with suicidal ideation (SI), 32 depressive patients without suicidal ideation (NS), and 44 healthy controls (HCs). All participants were scanned using 3T MRI to obtain resting-state functional images, and functional connectivity (FC), amplitude of low-frequency fluctuation (ALFF), regional homogeneity (ReHo), and graph theoretical analysis (GTA) were performed. We found functional activity differences, such as the hippocampus and thalamus, in the SI group compared with the NS group. We also concluded lower activity in the thalamus and cuneus regions were related to suicidal ideation. We also found several functional connectivity of the brain areas, such as hippocampus, cuneus, and frontal regions, in the SI group correlated with Hamilton Depression Rating Scale (HAM-D) and Hospital Anxiety and Depression Scale (HADS). A graph theoretical analysis (GTA) and network-based statistical (NBS) analysis revealed different topological organization and slightly better local segregation of the brain network in healthy participants compared with those in depressive patients with suicidal ideation. We suggest that brain functional connectivity may be affected in depressive patients with suicidal ideation.

PMID: 33420533 [PubMed - as supplied by publisher]

BCI Training Effects on Chronic Stroke Correlate with Functional Reorganization in Motor-Related Regions: A Concurrent EEG and fMRI Study.

Mon, 01/11/2021 - 00:48
Related Articles

BCI Training Effects on Chronic Stroke Correlate with Functional Reorganization in Motor-Related Regions: A Concurrent EEG and fMRI Study.

Brain Sci. 2021 Jan 06;11(1):

Authors: Yuan K, Chen C, Wang X, Chu WC, Tong RK

Abstract
Brain-computer interface (BCI)-guided robot-assisted training strategy has been increasingly applied to stroke rehabilitation, while few studies have investigated the neuroplasticity change and functional reorganization after intervention from multimodality neuroimaging perspective. The present study aims to investigate the hemodynamic and electrophysical changes induced by BCI training using functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) respectively, as well as the relationship between the neurological changes and motor function improvement. Fourteen chronic stroke subjects received 20 sessions of BCI-guided robot hand training. Simultaneous EEG and fMRI data were acquired before and immediately after the intervention. Seed-based functional connectivity for resting-state fMRI data and effective connectivity analysis for EEG were processed to reveal the neuroplasticity changes and interaction between different brain regions. Moreover, the relationship among motor function improvement, hemodynamic changes, and electrophysical changes derived from the two neuroimaging modalities was also investigated. This work suggested that (a) significant motor function improvement could be obtained after BCI training therapy, (b) training effect significantly correlated with functional connectivity change between ipsilesional M1 (iM1) and contralesional Brodmann area 6 (including premotor area (cPMA) and supplementary motor area (SMA)) derived from fMRI, (c) training effect significantly correlated with information flow change from cPMA to iM1 and strongly correlated with information flow change from SMA to iM1 derived from EEG, and (d) consistency of fMRI and EEG results illustrated by the correlation between functional connectivity change and information flow change. Our study showed changes in the brain after the BCI training therapy from chronic stroke survivors and provided a better understanding of neural mechanisms, especially the interaction among motor-related brain regions during stroke recovery. Besides, our finding demonstrated the feasibility and consistency of combining multiple neuroimaging modalities to investigate the neuroplasticity change.

PMID: 33418846 [PubMed - as supplied by publisher]

Presurgical brain mapping of the language network in pediatric patients with epilepsy using resting-state fMRI.

Sun, 01/10/2021 - 00:47
Related Articles

Presurgical brain mapping of the language network in pediatric patients with epilepsy using resting-state fMRI.

J Neurosurg Pediatr. 2021 Jan 08;:1-10

Authors: Pur DR, Eagleson R, Lo M, Jurkiewicz MT, Andrade A, de Ribaupierre S

Abstract
OBJECTIVE: Epilepsy affects neural processing and often causes intra- or interhemispheric language reorganization, rendering localization solely based on anatomical landmarks (e.g., Broca's area) unreliable. Preoperative brain mapping is necessary to weigh the risk of resection with the risk of postoperative deficit. However, the use of conventional mapping methods (e.g., somatosensory stimulation, task-based functional MRI [fMRI]) in pediatric patients is technically difficult due to low compliance and their unique neurophysiology. Resting-state fMRI (rs-fMRI), a "task-free" technique based on the neural activity of the brain at rest, has the potential to overcome these limitations. The authors hypothesized that language networks can be identified from rs-fMRI by applying functional connectivity analyses.
METHODS: Cases in which both task-based fMRI and rs-fMRI were acquired as part of the preoperative clinical protocol for epilepsy surgery were reviewed. Task-based fMRI consisted of 2 language tasks and 1 motor task. Resting-state fMRI data were acquired while the patients watched an animated movie and were analyzed using independent component analysis (i.e., data-driven method). The authors extracted language networks from rs-fMRI data by performing a similarity analysis with functionally defined language network templates via a template-matching procedure. The Dice coefficient was used to quantify the overlap.
RESULTS: Thirteen children underwent conventional task-based fMRI (e.g., verb generation, object naming), rs-fMRI, and structural imaging at 1.5T. The language components with the highest overlap with the language templates were identified for each patient. Language lateralization results from task-based fMRI and rs-fMRI mapping were comparable, with good concordance in most cases. Resting-state fMRI-derived language maps indicated that language was on the left in 4 patients (31%), on the right in 5 patients (38%), and bilateral in 4 patients (31%). In some cases, rs-fMRI indicated a more extensive language representation.
CONCLUSIONS: Resting-state fMRI-derived language network data were identified at the patient level using a template-matching method. More than half of the patients in this study presented with atypical language lateralization, emphasizing the need for mapping. Overall, these data suggest that this technique may be used to preoperatively identify language networks in pediatric patients. It may also optimize presurgical planning of electrode placement and thereby guide the surgeon's approach to the epileptogenic zone.

PMID: 33418528 [PubMed - as supplied by publisher]

Convolutional Neural Networks for Pediatric Refractory Epilepsy Classification Using Resting-State fMRI.

Sun, 01/10/2021 - 00:47
Related Articles

Convolutional Neural Networks for Pediatric Refractory Epilepsy Classification Using Resting-State fMRI.

World Neurosurg. 2021 Jan 05;:

Authors: Nguyen RD, Kennady EH, Smyth MD, Zhu L, Pao LP, Swisher SK, Rosas A, Mitra A, Patel RP, Lankford J, Von Allmen G, Watkins MW, Funke ME, Shah MN

Abstract
OBJECTIVE: This study aims to evaluate the performance of convolutional neural networks (CNN) trained with resting-state functional MRI (rfMRI) latency data in the classification of patients with pediatric epilepsy from healthy controls.
METHODS: Preoperative rfMRI and anatomical MRI scans were obtained from 63 pediatric patients with refractory epilepsy and 259 pediatric healthy controls. Latency maps of the temporal difference between rfMRI and the global mean signal were calculated using voxel-wise cross-covariance. Healthy control and epilepsy latency z-score maps were pseudorandomized and partitioned into training data (60%), validation data (20%) and test data (20%). Healthy control and epilepsy patients were labeled as negative and positive, respectively. CNN models were then trained with the designated training data. Model hyperparameters were evaluated with a grid-search method. The model with the highest sensitivity was evaluated using unseen test data. Accuracy, sensitivity, specificity, F1-score and AUC were used to evaluate the model's ability to classify epilepsy in the test data set.
RESULTS: The model with the highest validation sensitivity, correctly classified 74% of unseen test patients with 85% sensitivity, 71% specificity, F1-score of 0.56 and an AUC of 0.86.
CONCLUSION: Using rfMRI latency data, we trained a CNN model to classify pediatric epilepsy patients from healthy controls with good performance. CNN could serve as an adjunct in the diagnosis of pediatric epilepsy. Identification of pediatric epilepsy earlier in the disease course could decrease time to referral to specialized epilepsy centers, and thus improve prognosis in this population.

PMID: 33418117 [PubMed - as supplied by publisher]

A study of Regional Homogeneity of Resting-state Functional Magnetic Resonance Imaging in Mild Cognitive Impairment.

Sun, 01/10/2021 - 00:47
Related Articles

A study of Regional Homogeneity of Resting-state Functional Magnetic Resonance Imaging in Mild Cognitive Impairment.

Behav Brain Res. 2021 Jan 05;:113103

Authors: Liu L, Jiang H, Wang D, Zhao XF

Abstract
Mild cognitive impairment (MCI) is considered to be the early stage of Alzheimer's disease (AD), but the diagnostic predictive markers for MCI patients are still unclear. Here we have identified the brain function activity changes in MCI patients by using the resting-state Functional Magnetic Resonance Imaging (rs-fMRI). A total of 28 MCI patients and 38 age- and gender-matched healthy controls from the Wuxi Mental Health Center were recruited, and their abnormal spontaneous brain activities in the MCI were examined. The results showed that, compared with the healthy controls, MCI patients exhibited reduced Regional homogeneity (ReHo) in the right superior temporal gyrus, right middle temporal gyrus, left angular gyrus and superior marginal gyrus. In addition, the correlation analysis revealed that ReHo in the region was not correlated with the AD Assessment Scale-Cognitive score in MCI. We concluded abnormalities in the right superior temporal gyrus, right middle temporal gyrus, left angular gyrus and superior marginal gyrus with MCI, suggesting that the right language network may be impaired in MCI, which may provide a better understanding of dementia progression and potentially comprehensive treatment in MCI.

PMID: 33417993 [PubMed - as supplied by publisher]