scholarly journals Network variants are similar between task and rest states

2020 ◽  
Author(s):  
Brian T. Kraus ◽  
Diana Perez ◽  
Zach Ladwig ◽  
Benjamin A. Seitzman ◽  
Ally Dworetsky ◽  
...  
Keyword(s):  
Resting State ◽  
Resting State Fmri ◽  
Functional Networks ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Brain Organization ◽  
Precision Data ◽  
Specific Effects ◽  
Multiple Tasks ◽  
Over Time

AbstractRecent work has demonstrated that individual-specific variations in functional networks (that we call “network variants”) can be identified in individuals using functional magnetic resonance imaging (fMRI). These network variants exhibit reliability over time with resting-state fMRI data. These properties have suggested that network variants may be trait-like markers of individual differences in brain organization. Another test of this conclusion would be to examine if network variants are stable between task and rest states. Here, we use precision data from the Midnight Scan Club (MSC) to demonstrate that (1) task data can be used to identify network variants reliably, (2) these network variants show substantial spatial overlap with those observed in rest, although state-specific effects are present, (3) network variants assign to similar canonical functional networks in different states, and (4) single tasks or a combination of multiple tasks produce similar network variants to rest. Together, these findings further reinforce the trait-like nature of network variants and demonstrate the utility of using task data to define network variants.

A Critical, Event-Related Appraisal of Denoising in Resting-State fMRI Studies

2020 ◽  
Vol 30 (10) ◽  
pp. 5544-5559 ◽  
Author(s):  
Jonathan D Power ◽  
Charles J Lynch ◽  
Babatunde Adeyemo ◽  
Steven E Petersen
Keyword(s):  
Resting State ◽  
Resting State Fmri ◽  
Critical Event ◽  
Head Motion ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Decay Properties ◽  
Signal Decay ◽  
Biological Variables ◽  
Related Approach

Abstract This article advances two parallel lines of argument about resting-state functional magnetic resonance imaging (fMRI) signals, one empirical and one conceptual. The empirical line creates a four-part organization of the text: (1) head motion and respiration commonly cause distinct, major, unwanted influences (artifacts) in fMRI signals; (2) head motion and respiratory changes are, confoundingly, both related to psychological and clinical and biological variables of interest; (3) many fMRI denoising strategies fail to identify and remove one or the other kind of artifact; and (4) unremoved artifact, due to correlations of artifacts with variables of interest, renders studies susceptible to identifying variance of noninterest as variance of interest. Arising from these empirical observations is a conceptual argument: that an event-related approach to task-free scans, targeting common behaviors during scanning, enables fundamental distinctions among the kinds of signals present in the data, information which is vital to understanding the effects of denoising procedures. This event-related perspective permits statements like “Event X is associated with signals A, B, and C, each with particular spatial, temporal, and signal decay properties”. Denoising approaches can then be tailored, via performance in known events, to permit or suppress certain kinds of signals based on their desirability.

scholarly journals Prevalent and sex-biased breathing patterns modify functional connectivity MRI in young adults

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Charles J. Lynch ◽  
Benjamin M. Silver ◽  
Marc J. Dubin ◽  
Alex Martin ◽  
Henning U. Voss ◽  
...  
Keyword(s):  
Young Adults ◽  
Functional Connectivity ◽  
Resting State ◽  
Resting State Fmri ◽  
Resonance Imaging ◽  
Breathing Patterns ◽  
Resting State Functional Connectivity ◽  
Brain Organization ◽  
Normal Breathing ◽  
Functional Connectivity Mri

Abstract Resting state functional connectivity magnetic resonance imaging (fMRI) is a tool for investigating human brain organization. Here we identify, visually and algorithmically, two prevalent influences on fMRI signals during 440 h of resting state scans in 440 healthy young adults, both caused by deviations from normal breathing which we term deep breaths and bursts. The two respiratory patterns have distinct influences on fMRI signals and signal covariance, distinct timescales, distinct cardiovascular correlates, and distinct tendencies to manifest by sex. Deep breaths are not sex-biased. Bursts, which are serial taperings of respiratory depth typically spanning minutes at a time, are more common in males. Bursts share features of chemoreflex-driven clinical breathing patterns that also occur primarily in males, with notable neurological, psychiatric, medical, and lifespan associations. These results identify common breathing patterns in healthy young adults with distinct influences on functional connectivity and an ability to differentially influence resting state fMRI studies.

scholarly journals Correlation between the Effects of Acupuncture atTaichong(LR3) and Functional Brain Areas: A Resting-State Functional Magnetic Resonance Imaging Study Using True versus Sham Acupuncture

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Chunxiao Wu ◽  
Shanshan Qu ◽  
Jiping Zhang ◽  
Junqi Chen ◽  
Shaoqun Zhang ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Data Processing ◽  
Resting State ◽  
Resting State Fmri ◽  
Sham Acupuncture ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Brain Areas

Functional magnetic resonance imaging (fMRI) has been shown to detect the specificity of acupuncture points, as proved by numerous studies. In this study, resting-state fMRI was used to observe brain areas activated by acupuncture at theTaichong(LR3) acupoint. A total of 15 healthy subjects received brain resting-state fMRI before acupuncture and after sham and true acupuncture, respectively, at LR3. Image data processing was performed using Data Processing Assistant for Resting-State fMRI and REST software. The combination of amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo) was used to analyze the changes in brain function during sham and true acupuncture. Acupuncture at LR3 can specifically activate or deactivate brain areas related to vision, movement, sensation, emotion, and analgesia. The specific alterations in the anterior cingulate gyrus, thalamus, and cerebellar posterior lobe have a crucial effect and provide a valuable reference. Sham acupuncture has a certain effect on psychological processes and does not affect brain areas related to function.

scholarly journals Investigating the effects of healthy cognitive aging on brain functional connectivity using 4.7 T resting-state functional Magnetic Resonance Imaging

2020 ◽  
Author(s):  
Stanislau Hrybouski ◽  
Ivor Cribben ◽  
John McGonigle ◽  
Fraser Olsen ◽  
Rawle Carter ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Connectivity ◽  
Functional Magnetic Resonance Imaging ◽  
Age Differences ◽  
Resting State ◽  
Cognitive Aging ◽  
Resting State Fmri ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging

ABSTRACTIntroductionFunctional changes in the aging human brain have been previously reported using functional magnetic resonance imaging (fMRI). Earlier resting-state fMRI studies revealed an age-associated weakening of intra-system functional connectivity (FC) and age-associated strengthening of inter-system FC. However, the majority of such FC studies did not investigate the relationship between age and network amplitude, without which correlation-based measures of FC can be challenging to interpret. Consequently, the main aim of this study was to investigate how three primary measures of resting-state fMRI signal – network amplitude, network topography, and inter-network FC – are affected by healthy cognitive aging.MethodsWe acquired resting-state fMRI data on a 4.7 T scanner for 105 healthy participants representing the entire adult lifespan (18-85 years of age). To study age differences in network structure, we combined ICA-based network decomposition with sparse graphical models.ResultsOlder adults displayed lower blood-oxygen-level-dependent (BOLD) signal amplitude in all functional systems with sensorimotor networks showing the largest age differences. Our age comparisons of network topography and inter-network FC demonstrated a substantial amount of age-invariance in the brain’s functional architecture. Despite architecture similarities, old adults displayed a loss of communication efficiency in our inter-network FC comparisons, driven primarily by FC reduction in frontal and parietal association cortices. Together, our results provide a comprehensive overview of age effects on fMRI-based FC.

scholarly journals Customized head molds reduce motion during resting state fMRI scans

2018 ◽  
Author(s):  
Jonathan D Power ◽  
Benjamin Silver ◽  
Melanie R. Silverman ◽  
Eliana L. Ajodan ◽  
Dienke J. Bos ◽  
...  
Keyword(s):  
Resting State ◽  
Standard Procedure ◽  
Resting State Fmri ◽  
Motion Artifacts ◽  
Head Motion ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Quality Indices ◽  
Age Range ◽  
Head Coil

Head motion causes artifacts in functional magnetic resonance imaging (fMRI) scans, a problem especially relevant for task-free resting state paradigms and for developmental, aging, and clinical populations. In a cohort spanning 7-28 years old (mean age 15) we produced customized head-anatomy-specific Styrofoam molds for each subject that inserted into an MRI head coil. We scanned these subjects under two conditions: using our standard procedure of packing the head coil with foam padding about the head to reduce head motion, and using the customized molds to reduce head motion. Here we report the effects found in our first 13 subjects. In 12 of 13 subjects, the molds reduced head motion throughout the scan, and reduced the fraction of a scan with substantial motion (i.e., volumes with motion notably above baseline levels of motion). Motion was reduced in all 6 head position estimates, especially in rotational, left-right, and superior-inferior directions. Motion was reduced throughout the full age range studied, including children, adolescents, and young adults. In terms of the fMRI data itself, quality indices improved with the head mold on, scrubbing analyses detected less distance-dependent artifact in scans with the head mold on, and distant-dependent artifact was less evident in the scans with the molds on, both for the entire scan and also during only low-motion volumes. Subjects found the molds comfortable. Head molds are thus effective tools for reducing head motion, and motion artifacts, during fMRI scans.

Simultaneous Electroencephalographic and Functional Magnetic Resonance Imaging Indicate Impaired Cortical Top–Down Processing in Association with Anesthetic-induced Unconsciousness

2013 ◽  
Vol 119 (5) ◽  
pp. 1031-1042 ◽  
Author(s):  
Denis Jordan ◽  
Rüdiger Ilg ◽  
Valentin Riedl ◽  
Anna Schorer ◽  
Sabine Grimberg ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Resting State ◽  
Characteristic Curve ◽  
Resting State Fmri ◽  
Loss Of Consciousness ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Top Down

Abstract Background: In imaging functional connectivity (FC) analyses of the resting brain, alterations of FC during unconsciousness have been reported. These results are in accordance with recent electroencephalographic studies observing impaired top–down processing during anesthesia. In this study, simultaneous records of functional magnetic resonance imaging (fMRI) and electroencephalogram were performed to investigate the causality of neural mechanisms during propofol-induced loss of consciousness by correlating FC in fMRI and directional connectivity (DC) in electroencephalogram. Methods: Resting-state 63-channel electroencephalogram and blood oxygen level–dependent 3-Tesla fMRI of 15 healthy subjects were simultaneously registered during consciousness and propofol-induced loss of consciousness. To indicate DC, electroencephalographic symbolic transfer entropy was applied as a nonlinear measure of mutual interdependencies between underlying physiological processes. The relationship between FC of resting-state networks of the brain (z values) and DC was analyzed by a partial correlation. Results: Independent component analyses of resting-state fMRI showed decreased FC in frontoparietal default networks during unconsciousness, whereas FC in primary sensory networks increased. DC indicated a decline in frontal–parietal (area under the receiver characteristic curve, 0.92; 95% CI, 0.68–1.00) and frontooccipital (0.82; 0.53–1.00) feedback DC (P < 0.05 corrected). The changes of FC in the anterior default network correlated with the changes of DC in frontal–parietal (rpartial = +0.62; P = 0.030) and frontal–occipital (+0.63; 0.048) electroencephalographic electrodes (P < 0.05 corrected). Conclusion: The simultaneous propofol-induced suppression of frontal feedback connectivity in the electroencephalogram and of frontoparietal FC in the fMRI indicates a fundamental role of top–down processing for consciousness.

scholarly journals Resting-State fMRI in Studies of Acupuncture

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Xiaoling Li ◽  
Lina Cai ◽  
Xiaoxu Jiang ◽  
Xiaohui Liu ◽  
Jingxian Wang ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Resting State ◽  
Acupuncture Treatment ◽  
Physiological Mechanism ◽  
Resting State Fmri ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Visual Evidence ◽  
Acupuncture Research ◽  
Acupoint Stimulation

Research exploring the mechanism of acupuncture has been a hot topic in medicine. Resting-state functional magnetic resonance imaging (rs-fMRI) research is a noninvasive and extensive method, which is aimed at the research of the mechanism of acupuncture. Researchers use fMRI technologies to inspect the acupuncture process. The authors reviewed the application of rs-fMRI in acupuncture research in recent 10 years from the aspects of studying acupoints, subjects, acupuncture methods, and intensities. The results found that the application of rs-fMRI in acupuncture research mainly includes research on the onset mechanism of acupuncture treatment; visual evidence of diagnosis and treatment of dominant diseases; efficacy assessments; physiological mechanism of acupoint stimulation; and specific visualization of acupoints.

scholarly journals T156. FUNCTIONAL CONNECTIVITY AND RISK OF PSYCHOSIS: AN ACTIVATION LIKELIHOOD ESTIMATION (ALE) META-ANALYSIS OF FUNCTIONAL MAGNETIC RESONANCE IMAGING STUDIES

2020 ◽  
Vol 46 (Supplement_1) ◽  
pp. S290-S290
Author(s):  
Lorenzo Del Fabro ◽  
André Schmidt ◽  
Giuseppe Delvecchio ◽  
Armando D’Agostino ◽  
Stefan Borgwardt ◽  
...  
Keyword(s):  
At Risk ◽  
High Risk ◽  
Resting State ◽  
Large Scale ◽  
Meta Analysis ◽  
A Priori ◽  
Resting State Fmri ◽  
Healthy Controls ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging

Abstract Background Disrupted communication involving large-scale neural networks is hypothesized to underlie the pathophysiology of schizophrenia, as demonstrated by impaired resting-state functional connectivity (rsFC). Seed-based functional magnetic resonance imaging (fMRI) studies in subjects at increased risk of developing psychosis have begun to identify abnormalities in rsFC, although reported findings remain mixed. The aim of this study was to conduct a meta-analysis of seed-based resting-state fMRI studies to test whether high-risk subjects show rsFC alterations relative to healthy controls within and between the default mode network (DMN), control executive network (CEN), and salience network (SN). Methods A literature search was performed to identify seed-based resting-state fMRI studies comparing subjects with genetic risk factors, psychotic-like experiences, and clinical high-risk for psychosis to healthy controls. Then, coordinates of seed regions were extracted and categorized into networks by their location within a priori templates. Activation likelihood estimate (ALE) analysis examined the reported coordinates for hypo-connectivity and hyper-connectivity with each a priori network. Results The meta-analysis included 15 studies (774 subjects at risk, 628 healthy controls) on clinical high-risk for psychosis, 6 studies (123 subjects at risk, 147 healthy controls) on psychotic-like experiences, and 5 studies (173 subjects at risk, 256 healthy controls) on genetic risk factors of developing psychosis. We found specific patterns of hypo- and hyper-connectivity within and between large-scale networks. Our results showed that subjects with high-risk for psychosis were characterized by hypo-connectivity within the SN and CEN and hyper-connectivity within the DMN and CEN. Network seeds in the DMN, CEN, and SN displayed hyper-connectivity with regions in other networks. The DMN seeds displayed hypo-connectivity with regions in the CEN, while CEN and SN seeds displayed hypo-connectivity with regions in the DMN. Discussion This meta-analysis provides evidence that subjects at risk for psychosis present distinctive abnormalities of hyper- and hypo-connectivity within and between the DMN, CEN and SN, particularly implicating network dys-connectivity as a core deficit underlying the psychopathology of psychosis in the preclinical phase. More studies are needed to investigate whether subjects at risk to develop psychosis present patterns of dysfunction between the rsFC of healthy subjects and that of patients with established psychosis.

scholarly journals Aνάπτυξη τεχνικών επεξεργασίας δεδομένων λειτουργικού μαγνητικού συντονισμού για τον προσδιορισμό δικτύων λειτουργικής συνδεσιμότητας σε ασθενή και υγιή πληθυσμό

2017 ◽  
Author(s):  
Κωνσταντίνος Μπρόμης
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Resting State ◽  
Resting State Fmri ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging

Αντικείμενο της παρούσας διδακτορικής διατριβής αποτελεί η διερεύνηση λειτουργικών μεταβολών σε περιοχές και σε δίκτυα του εγκεφάλου που σχετίζονται με γνωστικές (γνωσιακές) καθώς και κινητικές λειτουργίες σε ασθενείς με Μικροκυτταρικό Καρκίνο του Πνεύμονα (ΜΚΠ) μετά από χημειοθεραπεία και πριν τη θεραπεία με Προφυλακτική Κρανιακή Ακτινοβολία (ΠΚΑ), στοχεύοντας στον εντοπισμό του νευρικού κυκλώματος που συμμετέχει στις εν λόγω γνωστικές λειτουργίες. Στο πλαίσιο αυτό, εκπονήθηκαν δύο πειράματα με χρήση της τεχνικής Απεικόνισης Λειτουργικού Μαγνητικού Συντονισμού (functional Magnetic Resonance Imaging - fMRI): α) πείραμα με βάση ερέθισμα που προκλήθηκε από χτύπημα των δακτύλων του χεριού με τον αντίχειρα καθώς και β) πείραμα σε κατάσταση ηρεμίας (resting-state fMRI / rs-fMRI).Στα δεδομένα που προέρχονται από το πείραμα με ερέθισμα που προκλήθηκε από χτύπημα των δακτύλων του χεριού με τον αντίχειρα, εφαρμόστηκαν προηγμένες τεχνικές προεπεξεργασίας και στατιστικής ανάλυσης εικόνων fMRI. Συγκεκριμένα, πραγματοποιήθηκε προεπεξεργασία των δεδομένων τόσο ως προς το χρόνο όσο και ως προς το χώρο στοχεύοντας στην απομάκρυνση τεχνικών σφαλμάτων ώστε να είναι εφικτή η ακριβής λήψη αποτελεσμάτων κατά τη στατιστική ανάλυση. Από τις προεπεξεργασμένες fMRI εικόνες εξήχθησαν στη συνέχεια οι χρονοσειρές των τρισδιάστατων εικονοστοιχείων (voxel), οι οποίες μοντελοποιήθηκαν στη συνέχεια κάνοντας χρήση του Γενικού Γραμμικού Μοντέλου με στόχο τη δημιουργία των χαρτών ενεργοποίησης. Οι χάρτες ενεργοποίησης παρουσιάζουν την ενεργοποίηση και την αιμοδυναμική απόκριση του εγκεφάλου μετά από ερέθισμα κατά τη λήψη των λειτουργικών απεικονίσεων. Τα αποτελέσματα του πειράματος από ερέθισμα δεν κατέδειξαν λειτουργική διαφοροποίηση στον κινητικό φλοιό στους ασθενείς με ΜΚΠ αποδεικνύοντας ότι πιθανόν η συγκεκριμένη περιοχή του εγκεφάλου δεν επηρεάζεται από τις τοξικές επιδράσεις της χημειοθεραπείας.Στα δεδομένα που προέρχονται από το πείραμα σε κατάσταση ηρεμίας, πραγματοποιήθηκε αρχικά προεπεξεργασία, όπως και στο πρώτο πείραμα. Για την εξαγωγή των δικτύων του εγκεφάλου που ενεργοποιούνται εφαρμόστηκαν τρείς διαφορετικές μεθοδολογικές προσεγγίσεις με στόχο την καταγραφή διαφοροποιήσεων στη λειτουργική συνδεσιμότητα του εγκεφάλου ασθενών με ΜΚΠ. Συγκεκριμένα, εφαρμόστηκε η Ανάλυση Ανεξάρτητων Συνιστωσών (ΑΑΣ) στοχεύοντας στην εύρεση ενός συνόλου από στατιστικά ανεξάρτητους χωρικούς χάρτες (λειτουργικά δίκτυα εγκεφάλου) μαζί με τις αντίστοιχες χρονοσειρές τους. Επιπροσθέτως, εφαρμόστηκαν οι μέθοδοι της Ανάλυσης Συσχετισμού Βασισμένη σε Σπόρους και της Ανάλυσης Συσχετισμού Βασισμένη σε Κόμβους όπου εξήχθησαν χάρτες λειτουργικής συνδεσιμότητας που εκφράζουν τη χρονική συσχέτιση των περιοχών του εγκεφάλου που συνιστούν το κάθε δίκτυο που εξερευνήθηκε. Τα αποτελέσματα από το πείραμα σε κατάσταση ηρεμίας κατέδειξαν λειτουργικές διαφοροποιήσεις για τους ασθενείς με ΜΚΠ σε περιοχές του εγκεφάλου που σχετίζονται με τις γνωστικές λειτουργίες.Στη συνέχεια, και για τα δεδομένα του πειράματος ηρεμίας, αναπτύχθηκε και εφαρμόστηκε αλγόριθμος βασισμένος στη θεωρία των γράφων στοχεύοντας στον καθορισμό των τοπολογικών ιδιοτήτων μικρού κόσμου που διέπει η σχέση μεταξύ των δικτύων του εγκεφάλου. Όλα τα fMRI δεδομένα σε κατάσταση ηρεμίας μετασχηματίστηκαν σε δομές γράφων όπου κάθε κόμβος αναπαριστά ένα εγκεφαλικό δίκτυο και η συνδεσιμότητα μεταξύ των κόμβων αναπαριστά την ομοιότητα στην ενεργοποίηση αυτών των δικτύων. Κάθε γράφος μπορεί στη συνέχεια να συνοψιστεί με τις ιδιότητες συνδεσιμότητας του. Στην παρούσα μελέτη, εξερευνήθηκε ένας μεγάλος αριθμός μετρικών γράφων όπως το μέσο μήκος διαδρομής, η πυκνότητα γραφήματος, ο συντελεστής ομαδοποίησης και η μικροκοσμικότητα (small-worldness) των γράφων. Παράλληλα, προτείνεται μια εναλλακτική προσέγγιση υπολογισμού της μικροκοσμικότητας των δικτύων, η οποία χαρακτηρίζει με μεγαλύτερη ακρίβεια τα δίκτυα μικρού κόσμου σε σχέση με την καθιερωμένη προσέγγιση. Ο αλγόριθμος εφαρμόστηκε στα fMRI δεδομένα σε κατάσταση ηρεμίας της παρούσας εργασίας όπου δεν παρατηρήθηκε κάποια στατιστικά σημαντική διαφοροποίηση μεταξύ των ασθενών με ΜΚΠ και των υγιών εξεταζόμενων. Και οι δύο ομάδες εμφάνισαν χαρακτηριστικά μικροκοσμικότητας, με τους υγιείς να εμφανίζουν ιδιότητες δικτύων που είναι πιο κοντά σε αυτό του κανονικού πλέγματος (δηλ. υψηλότερο συντελεστή ομαδοποίησης), ενώ οι ασθενείς εμφάνισαν ιδιότητες που είναι πιο κοντά σε αυτό ενός τυχαίου γράφου (δηλ. μικρότερο μήκος μονοπατιού).

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