title: Does function fit structure? A ground truth for non-invasive neuroimaging.
abstract: There are now a number of non-invasive methods to image human brain function in-vivo. However, the accuracy of these images remains unknown and can currently only be estimated through the use of invasive recordings to generate a functional ground truth. Neuronal activity follows grey matter structure and accurate estimates of neuronal activity will have stronger support from accurate generative models of anatomy. Here we introduce a general framework that, for the first time, enables the spatial distortion of a functional brain image to be estimated empirically. We use a spherical harmonic decomposition to modulate each cortical hemisphere from its original form towards progressively simpler structures, ending in an ellipsoid. Functional estimates that are not supported by the simpler cortical structures have less inherent spatial distortion. This method allows us to compare directly between magnetoencephalography (MEG) source reconstructions based upon different assumption sets without recourse to functional ground truth.
authors.affiliation: School of Physics and Astronomy, Nottingam, UK.
authors.forename: Claire
authors.initials: C
authors.lastname: Stevenson
authors.affiliation: School of Physics and Astronomy, Nottingam, UK.
authors.forename: Matthew
authors.initials: M
authors.lastname: Brookes
authors.affiliation: SISTEMIC, Engineering Faculty, Universidad de Antioquia, Medellín, Colombia.
authors.forename: José David
authors.initials: JD
authors.lastname: López
authors.affiliation: Wellcome Trust Centre for Neuroimaging, London, UK.
authors.forename: Luzia
authors.initials: L
authors.lastname: Troebinger
authors.affiliation: INSERM, Lyon, France.
authors.forename: Jeremie
authors.initials: J
authors.lastname: Mattout
authors.affiliation: Wellcome Trust Centre for Neuroimaging, London, UK.
authors.forename: William
authors.initials: W
authors.lastname: Penny
authors.affiliation: School of Physics and Astronomy, Nottingam, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Morris
authors.affiliation: VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Arjan
authors.initials: A
authors.lastname: Hillebrand
authors.affiliation: MRC CBU, Cambridge, UK.
authors.forename: Richard
authors.initials: R
authors.lastname: Henson
authors.affiliation: Wellcome Trust Centre for Neuroimaging, London, UK. Electronic address: g.barnes@ucl.ac.uk.
authors.forename: Gareth
authors.initials: G
authors.lastname: Barnes
mesh_terms: D000465:Algorithms; D001931:Brain Mapping / Q000379:methods*; D003198:Computer Simulation; D066128:Gray Matter / Q000033:anatomy & histology* / Q000502:physiology*; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods*; D008953:Models, Anatomic; D008959:Models, Neurological; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity