Resting-state functional connectivity in children cooled for neonatal encephalopathy

Therapeutic hypothermia improves outcomes following neonatal hypoxic-ischaemic encephalopathy (HIE), reducing cases of death and severe disability such as cerebral palsy compared to normothermia management. However, when cooled children reach early school-age they have cognitive and motor impairments which are associated with underlying alterations to brain structure and white matter connectivity. It is unknown whether these differences in structural connectivity are associated with differences in functional connectivity between cooled children and healthy controls. Resting-state fMRI has been used to characterise static and dynamic functional connectivity in children, both with typical development and those with neurodevelopmental disorders. Previous studies of resting-state brain networks in children with HIE have focussed on the neonatal period. In this study, we used resting-state fMRI to investigate static and dynamic functional connectivity in children aged 6-8 years who were cooled for neonatal HIE without cerebral palsy (n = 22, median age [IQR] 7.08 [6.85-7.52] years), and healthy controls matched for age, sex and socioeconomic status (n = 20, median age [IQR] 6.75 [6.48-7.25] years). Using group independent component analysis, we identified 31 intrinsic functional connectivity networks consistent with those previously reported in children and adults. We found no case-control differences in the spatial maps of these intrinsic connectivity networks. We constructed subject-specific static functional connectivity networks by measuring pairwise Pearson correlations between component time courses, and found no case-control differences in functional connectivity after FDR correction. To study the time-varying organisation of resting-state networks, we used sliding-window correlations and deep clustering to investigate dynamic functional connectivity characteristics. We found k = 4 repetitively occurring functional connectivity states, which exhibited no case-control differences in dwell time, fractional occupancy, or state functional connectivity matrices. In this small cohort, the spatiotemporal characteristics of resting-state brain networks in cooled children without severe disability were too subtle to be differentiated from healthy controls at early school-age, despite underlying differences in brain structure and white matter connectivity, possibly reflecting a level of recovery of healthy resting-state brain function. To our knowledge, this is the first study to investigate resting-state functional connectivity in children with HIE beyond the neonatal period, and the first to investigate dynamic functional connectivity in any children with HIE. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work was supported by the Baily Thomas Charitable Fund (TRUST/VC/AC/SG4681-7596), David Telling Charitable Trust, as well as Sparks (05/BTL/01 and 14/BTL/01), the Moulton Foundation, and the Wellcome Trust (WT220070/Z/20/Z). JCWB is supported by the UK Medical Research Council (MR/N026969/1). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethical approval was obtained from the North Bristol Research Ethics Committee and the Health Research Authority (15/SW/0148). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes The data that support the findings of this study are available from the corresponding author, upon reasonable request. The code used for dFC analysis (including sliding-window correlations and deep clustering) is available at GitHub () ([Spencer and Goodfellow, 2022][1]). [1]: #ref-60