Psychological Medicine cambridge.org/psm Original Article Cite this article: Park HRP, Chilver MR, Montalto A, Jamshidi J, Schofield PR, Williams LM, Gatt JM (2021). Associations between mental wellbeing and fMRI neural bases underlying responses to positive emotion in a twin sample. Psychological Medicine 1–9. https://doi.org/10.1017/S0033291721002695 Received: 23 September 2020 Revised: 7 May 2021 Accepted: 14 June 2021 Key words: emotion; faces; fMRI; happy; heritability; twins; wellbeing Author for correspondence: Haeme R.P. Park, E-mail: h.park@neura.edu.au © The Author(s), 2021. Published by Cambridge University Press Associations between mental wellbeing and fMRI neural bases underlying responses to positive emotion in a twin sample Haeme R.P. Park 1,2 , Miranda R. Chilver 1,2 , Arthur Montalto 1,2 , Javad Jamshidi 1,2 , Peter R. Schofield 1,3 , Leanne M. Williams 4 and Justine M. Gatt 1,2 1 Neuroscience Research Australia, Sydney, NSW, Australia; 2 School of Psychology, University of New South Wales, Sydney, NSW, Australia; 3 School of Medical Science, University of New South Wales, Sydney, NSW, Australia and 4 Psychiatry and Behavioral Sciences, Stanford School of Medicine, Stanford University, Stanford, California, USA Abstract Background. Although mental wellbeing has been linked with positive health outcomes, including longevity and improved emotional and cognitive functioning, studies examining the underlying neural mechanisms of both subjective and psychological wellbeing have been sparse. We assessed whether both forms of wellbeing are associated with neural activity engaged during positive and negative emotion processing and the extent to which this asso- ciation is driven by genetics or environment. Methods. We assessed mental wellbeing in 230 healthy adult monozygotic and dizygotic twins using a previously validated questionnaire (COMPAS-W) and undertook functional magnetic resonance imaging during a facial emotion viewing task. We used linear mixed models to analyse the association between COMPAS-W scores and emotion-elicited neural activation. Univariate twin modelling was used to evaluate heritability of each brain region. Multivariate twin modelling was used to compare twin pairs to assess the contributions of genetic and environmental factors to this association. Results. Higher levels of wellbeing were associated with greater neural activity in the dorso- lateral prefrontal cortex, localised in the right inferior frontal gyrus (IFG), in response to posi- tive emotional expressions of happiness. Univariate twin modelling showed activity in the IFG to have 20% heritability. Multivariate twin modelling suggested that the association between wellbeing and positive emotion-elicited neural activity was driven by common variance from unique environment (r = 0.208) rather than shared genetics. Conclusions. Higher mental wellbeing may have a basis in greater engagement of prefrontal neural regions in response to positive emotion, and this association may be modifiable by unique life experiences. Introduction Although many psychological factors have been established as contributing to optimal mental health (including purpose in life, autonomy, positive affect; Keyes, 2007), we lack knowledge regarding the underlying neurobiological mechanisms by which such factors relate to well- being, which is comprised of two distinct, yet correlated, sub-constructs: subjective and psy- chological wellbeing. Subjective wellbeing relates to factors such as happiness, positive affect and life satisfaction, while psychological wellbeing refers to personal attributes such as auton- omy, mastery, self-acceptance and finding a meaningful life purpose (Diener, Suh, Lucas, & Smith, 1999; Ryff & Singer, 2008). Although both sub-constructs have been extensively linked to positive outcomes such as decreased physical illness, greater work productivity and superior psychosocial functioning (e.g. Steptoe, Deaton, & Stone, 2015), they have often been examined independently of one another. However, it has been shown that they both contribute import- ant and unique variance to total wellbeing (Henderson & Knight, 2012; Keyes & Annas, 2009), highlighting the importance of examining both aspects of wellbeing as one composite construct. Reappraisal of emotional information is considered to be an important determinant of mental health outcomes including wellbeing (Davidson, 2004). Despite multiple behavioural studies showing an association between wellbeing and reaction time or accuracy to emotional stimuli, the corresponding evidence using neuroimaging methods is sparser and somewhat contradictory. In those neuroimaging studies available, wellbeing is usually only measured using subjective wellbeing or psychological wellbeing measures, but rarely both. Moreover, understanding whether the association between wellbeing and emotion processing is driven by genetics or environment (as can be evaluated using twin studies) would assist in https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0033291721002695 Downloaded from https://www.cambridge.org/core. IP address: 207.241.225.241, on 01 Sep 2021 at 17:21:51, subject to the Cambridge Core terms of use, available at