title: Does motion-related brain functional connectivity reflect both artifacts and genuine neural activity?
abstract: Imaging research on functional connectivity is uniquely contributing to characterize the functional organization of the human brain. Functional connectivity measurements, however, may be significantly influenced by head motion that occurs during image acquisition. The identification of how motion influences such measurements is therefore highly relevant to the interpretation of a study's results. We have mapped the effect of head motion on functional connectivity in six different populations representing a wide range of potential influences of motion on functional connectivity. Group-level voxel-wise maps of the correlation between a summary head motion measurement and functional connectivity degree were estimated in 80 young adults, 71 children, 53 older adults, 20 patients with Down syndrome, 24 with Prader-Willi syndrome and 20 with Williams syndrome. In highly compliant young adults, motion correlated with functional connectivity measurements showing a system-specific anatomy involving the sensorimotor cortex, visual areas and default mode network. Further characterization was strongly indicative of these changes expressing genuine neural activity related to motion, as opposed to pure motion artifact. In the populations with larger head motion, results were more indicative of widespread artifacts, but showing notably distinct spatial distribution patterns. Group-level regression of motion effects was efficient in removing both generalized changes and changes putatively related to neural activity. Overall, this study endorses a relatively simple approach for mapping distinct effects of head motion on functional connectivity. Importantly, our findings support the intriguing hypothesis that a component of motion-related changes may reflect system-specific neural activity.
authors.affiliation: MRI Research Unit, CRC Mar, Hospital del Mar, Barcelona, Spain; Centro Investigación Biomédica en Red de Salud Mental, CIBERSAM G21, Barcelona, Spain. Electronic address: jpujol@crccorp.es.
authors.forename: Jesus
authors.initials: J
authors.lastname: Pujol
authors.affiliation: MRI Research Unit, CRC Mar, Hospital del Mar, Barcelona, Spain.
authors.forename: Dídac
authors.initials: D
authors.lastname: Macià
authors.affiliation: MRI Research Unit, CRC Mar, Hospital del Mar, Barcelona, Spain; Human Pharmacology and Clinical Neurosciences, Hospital del Mar Medical Research Institute, Barcelona, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Blanco-Hinojo
authors.affiliation: MRI Research Unit, CRC Mar, Hospital del Mar, Barcelona, Spain.
authors.forename: Gerard
authors.initials: G
authors.lastname: Martínez-Vilavella
authors.affiliation: Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain; Universitat Pompeu Fabra (UFP), Barcelona, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Sunyer
authors.affiliation: Human Pharmacology and Clinical Neurosciences, Hospital del Mar Medical Research Institute, Barcelona, Spain; CIBER-Fisiopatología de la Obesidad y Nutrición (CIBEROBN), S. de Compostela, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: de la Torre
authors.affiliation: Diabetes Endocrinology and Nutrition Department, Hospital de Sabadell, Institut Universitari Parc Taulí, Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: Assumpta
authors.initials: A
authors.lastname: Caixàs
authors.affiliation: Department of Psychiatry and Clinical Psychobiology, Clinical Institute of Neuroscience, Hospital Clínic, CIBERSAM, University of Barcelona, Barcelona, Spain.
authors.forename: Rocío
authors.initials: R
authors.lastname: Martín-Santos
authors.affiliation: MRI Research Unit, CRC Mar, Hospital del Mar, Barcelona, Spain; Department of Clinical and Health Psychology, Autonomous University of Barcelona, Barcelona, Spain.
authors.forename: Joan
authors.initials: J
authors.lastname: Deus
authors.affiliation: Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne, Melbourne, Australia.
authors.forename: Ben J
authors.initials: BJ
authors.lastname: Harrison
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology* / Q000503:physiopathology; D001931:Brain Mapping / Q000379:methods* / Q000592:standards; D002648:Child; D005260:Female; D006257:Head; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009038:Motion; D009415:Nerve Net / Q000033:anatomy & histology / Q000502:physiology* / Q000503:physiopathology; D066191:Sensorimotor Cortex / Q000033:anatomy & histology / Q000502:physiology / Q000503:physiopathology; D055815:Young Adult
keywords: Brain networks; Default mode network; Head motion; Resting-state; Sensorimotor cortex; fMRI