title: Heritability of head motion during resting state functional MRI in 462 healthy twins.
abstract: Head motion (HM) is a critical confounding factor in functional MRI. Here we investigate whether HM during resting state functional MRI (RS-fMRI) is influenced by genetic factors in a sample of 462 twins (65% female; 101 MZ (monozygotic) and 130 DZ (dizygotic) twin pairs; mean age: 21 (SD = 3.16), range 16-29). Heritability estimates for three HM components-mean translation (MT), maximum translation (MAXT) and mean rotation (MR)-ranged from 37 to 51%. We detected a significant common genetic influence on HM variability, with about two-thirds (genetic correlations range 0.76-1.00) of the variance shared between MR, MT and MAXT. A composite metric (HM-PC1), which aggregated these three, was also moderately heritable (h(2) = 42%). Using a sub-sample (N = 35) of the twins we confirmed that mean and maximum translational and rotational motions were consistent "traits" over repeated scans (r = 0.53-0.59); reliability was even higher for the composite metric (r = 0.66). In addition, phenotypic and cross-trait cross-twin correlations between HM and resting state functional connectivities (RS-FCs) with Brodmann areas (BA) 44 and 45, in which RS-FCs were found to be moderately heritable (BA44: h(2) = 0.23 (sd = 0.041), BA45: h(2) = 0.26 (sd = 0.061)), indicated that HM might not represent a major bias in genetic studies using FCs. Even so, the HM effect on FC was not completely eliminated after regression. HM may be a valuable endophenotype whose relationship with brain disorders remains to be elucidated.
authors.affiliation: QIMR Berghofer Medical Research Institute, Brisbane, Australia; School of Psychology, University of Queensland, Brisbane, Australia; Centre for Advanced Imaging, University of Queensland, Brisbane, Australia. Electronic address: baptiste.couvyduchesne@qimrberghofer.edu.au.
authors.forename: Baptiste
authors.initials: B
authors.lastname: Couvy-Duchesne
authors.affiliation: QIMR Berghofer Medical Research Institute, Brisbane, Australia; School of Psychology, University of Queensland, Brisbane, Australia.
authors.forename: Gabriëlla A M
authors.initials: GA
authors.lastname: Blokland
authors.affiliation: Brain & Mind Research Institute, University of Sydney, Australia.
authors.forename: Ian B
authors.initials: IB
authors.lastname: Hickie
authors.affiliation: Imaging Genetics Center, Laboratory of Neuro-Imaging, Dept. of Neurology & Psychiatry, UCLA School of Medicine, Los Angeles, CA, USA.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Thompson
authors.affiliation: QIMR Berghofer Medical Research Institute, Brisbane, Australia.
authors.forename: Nicholas G
authors.initials: NG
authors.lastname: Martin
authors.affiliation: School of Psychology, University of Queensland, Brisbane, Australia.
authors.forename: Greig I
authors.initials: GI
authors.lastname: de Zubicaray
authors.affiliation: Centre for Advanced Imaging, University of Queensland, Brisbane, Australia.
authors.forename: Katie L
authors.initials: KL
authors.lastname: McMahon
authors.affiliation: QIMR Berghofer Medical Research Institute, Brisbane, Australia.
authors.forename: Margaret J
authors.initials: MJ
authors.lastname: Wright
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D058068:Endophenotypes; D005260:Female; D019416:Head Movements; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009415:Nerve Net / Q000502:physiology*; D012146:Rest; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic; D055815:Young Adult
keywords: Broca's area; Head motion; Heritability; Resting state fMRI; Twin study