“…The proposed model can be regarded as an extension of the classical single-trait and bivariate-trait variance component models in Amos (1994); Almasy et al (1997) and is formulated as a multivariate mixed effects model on the Karhunen-Loève basis coefficients of the tangent space coordinates. If instead, the aim of the analysis was to estimate joint modes of variation in shape and connectivity, regardless of their sources, a Canonical Correlation Analysis (CCA) (Hotelling, 1936;Johnson and Wichern, 2002) or an Angle-based Joint and Individual Variation Explained (AJIVE) analysis could have been performed on the tangent space coordinates (Lock et al, 2013;Feng et al, 2018;Carmichael et al, 2019).…”