ORCID Profile
0000-0002-3976-189X
Current Organisation
Griffith University
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Publisher: Elsevier BV
Date: 2019
Publisher: MDPI AG
Date: 09-12-2022
Abstract: Differential axonal myelination synchronises signalling over different axon lengths. The consequences of myelination processes described at the cellular level for the regulation of myelination at the macroscopic level are unknown. We analysed multiple cohorts of myelin-sensitive brain MRI. Our aim was to (i) confirm a previous report of anti-correlation between myelination in subcortical and sensorimotor areas in healthy subjects, (ii) and thereby test our hypothesis for a regulatory interaction between them. We analysed nine image-sets across three different human cohorts using six MRI modalities. Each image-set contained healthy controls (HC) and ME/CFS subjects. Subcortical and Sensorimotor regions of interest (ROI) were optimised for the detection of anti-correlations and the same ROIs were used to test the HC in all image-sets. For each cohort, median MRI values were computed in both regions for each subject and their correlation across the cohort was computed. We confirmed negative correlations in healthy controls between subcortical and sensorimotor regions in six image-sets: three T1wSE (p = 5 × 10−8, 5 × 10−7, 0.002), T2wSE (p =2 × 10−6), MTC (p = 0.01), and WM volume (p = 0.02). T1/T2 was the exception with a positive correlation (p = 0.01). This myelin regulation study is novel in several aspects: human subjects, cross-sectional design, ROI optimization, spin-echo MRI and reproducible across multiple independent image-sets. In multiple independent image-sets we confirmed an anti-correlation between subcortical and sensorimotor myelination which supports a previously unreported regulatory interaction. The subcortical region contained the brain’s primary regulatory nuclei. We suggest a mechanism has evolved whereby relatively low subcortical myelination in an in idual is compensated by upregulated sensorimotor myelination to maintain adequate sensorimotor performance.
Publisher: Mary Ann Liebert Inc
Date: 04-2023
Abstract: Myalgic Encephalomyelitis or Chronic Fatigue Syndrome (ME/CFS) is a debilitating disease with unknown pathophysiology. Functional MRI (fMRI) studies in ME/CFS have reported disparate connectivities for the brain salience (SA) and default mode (DMN) networks. In this study, we acquired resting state and task fMRI with an advanced scanner for improved subject numbers: 24 healthy controls (HC) and 42 ME/CFS patients, 18 meeting International Consensus Criteria (ICC) and 24 meeting Fukuda criteria. We evaluated mean FC between SA and DMN network hub, and subcortical regions known to be involved in ME/CFS. We tested the hypothesis that ME/CFS connectivity differed from HC and the ICC and Fukuda classes are distinguished by different connectivities with HC for different pairs of SA, DMN or subcortical hubs. During resting state fMRI only two connections differed from HC, both for Fukuda ME/CFS and both with an SA hub. During task fMRI 10 ME/CFS connections differed from HC, 5 for ICC and 5 for Fukuda. None were common to both classes. Eight of the 10 different connections involved an SA hub, six of 10 were weaker in ME/CFS, 4 stronger. SA connections to the hippoc us and brainstem reticular activation system (RAS) differed from and were stronger than HC. The SA mediates the relative activity of the DMN and executive networks and imbalance will have functional consequences. The RAS and hippoc us modulate cortical activation. Different regulatory connections are consistent with the impaired cognitive performance and sleep-wake cycle of ME/CFS. Different neuropathology is involved in ICC and Fukuda classes.
Publisher: Wiley
Date: 31-03-2022
DOI: 10.1002/JNR.25048
Abstract: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) patients suffer from a cognitive and memory dysfunction. Because the hippoc us plays a key role in both cognition and memory, we tested for volumetric differences in the subfields of the hippoc us in ME/CFS. We estimated hippoc al subfield volumes for 25 ME/CFS patients who met Fukuda criteria only (ME/CFS Fukuda ), 18 ME/CFS patients who met the stricter ICC criteria (ME/CFS ICC ), and 25 healthy controls (HC). Group comparisons with HC detected extensive differences in subfield volumes in ME/CFS ICC but not in ME/CFS Fukuda . ME/CFS ICC patients had significantly larger volume in the left subiculum head ( p 0.001), left presubiculum head ( p = 0.0020), and left fimbria ( p = 0.004). Correlations of hippoc us subfield volumes with clinical measures were stronger in ME/CFS ICC than in ME/CFS Fukuda patients. In ME/CFS Fukuda patients, we detected positive correlations between fatigue and hippoc us subfield volumes and a negative correlation between sleep disturbance score and the right CA1 body volume. In ME/CFS ICC patients, we detected a strong negative relationship between fatigue and left hippoc us tail volume. Strong negative relationships were also detected between pain and SF36 physical scores and two hippoc al subfield volumes (left: GC‐ML‐DG head and CA4 head). Our study demonstrated that volumetric differences in hippoc al subfields have strong statistical inference for patients meeting the ME/CFS ICC case definition and confirms hippoc al involvement in the cognitive and memory problems of ME/CFS ICC patients.
No related grants have been discovered for Leighton BARNDEN.