title: Heritable influences on amygdala and orbitofrontal cortex contribute to genetic variation in core dimensions of personality.
abstract: While many studies have reported that individual differences in personality traits are genetically influenced, the neurobiological bases mediating these influences have not yet been well characterized. To advance understanding concerning the pathway from genetic variation to personality, here we examined whether measures of heritable variation in neuroanatomical size in candidate regions (amygdala and medial orbitofrontal cortex) were associated with heritable effects on personality. A sample of 486 middle-aged (mean=55 years) male twins (complete MZ pairs=120; complete DZ pairs=84) underwent structural brain scans and also completed measures of two core domains of personality: positive and negative emotionality. After adjusting for estimated intracranial volume, significant phenotypic (r(p)) and genetic (r(g)) correlations were observed between left amygdala volume and positive emotionality (r(p)=.16, p<.01; r(g)=.23, p<.05, respectively). In addition, after adjusting for mean cortical thickness, genetic and nonshared-environmental correlations (r(e)) between left medial orbitofrontal cortex thickness and negative emotionality were also observed (r(g)=.34, p<.01; r(e)=-.19, p<.05, respectively). These findings support a model positing that heritable bases of personality are, at least in part, mediated through individual differences in the size of brain structures, although further work is still required to confirm this causal interpretation.
authors.affiliation: Department of Psychology, University of York, Heslington, York, YO10 5DD, UK. Electronic address: gary.lewis@york.ac.uk.
authors.forename: G J
authors.initials: GJ
authors.lastname: Lewis
authors.affiliation: Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093, USA.
authors.forename: M S
authors.initials: MS
authors.lastname: Panizzon
authors.affiliation: Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093, USA; Mental Illness Research, Education, & Clinical Center, VA San Diego Healthcare System, San Diego, CA 92093, USA.
authors.forename: L
authors.initials: L
authors.lastname: Eyler
authors.affiliation: Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093, USA; Department of Radiology, University of California, San Diego, La Jolla, CA 92093, USA.
authors.forename: C
authors.initials: C
authors.lastname: Fennema-Notestine
authors.affiliation: Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093, USA; Department of Radiology, University of California, San Diego, La Jolla, CA 92093, USA.
authors.forename: C-H
authors.initials: CH
authors.lastname: Chen
authors.affiliation: Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University School of Medicine, Richmond, VA 23219, USA.
authors.forename: M C
authors.initials: MC
authors.lastname: Neale
authors.affiliation: Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093, USA; Department of Cognitive Science, University of California, San Diego, La Jolla, CA 92093, USA.
authors.forename: T L
authors.initials: TL
authors.lastname: Jernigan
authors.affiliation: Department of Psychology, Boston University, Boston, MA 02215, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Lyons
authors.affiliation: Department of Radiology, University of California, San Diego, La Jolla, CA 92093, USA; Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Dale
authors.affiliation: Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093, USA; Center for Behavioral Genomics, University of California, San Diego, La Jolla, CA 92093, USA; Center of Excellence for Stress and Mental Health, VA San Diego Healthcare System, La Jolla, CA 92093, USA.
authors.forename: W S
authors.initials: WS
authors.lastname: Kremen
authors.affiliation: Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093, USA; Center for Behavioral Genomics, University of California, San Diego, La Jolla, CA 92093, USA.
authors.forename: C E
authors.initials: CE
authors.lastname: Franz
mesh_terms: D000679:Amygdala / Q000033:anatomy & histology*; D005260:Female; D005625:Frontal Lobe / Q000033:anatomy & histology*; D014644:Genetic Variation; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D010551:Personality / Q000235:genetics*; D010641:Phenotype
keywords: Amygdala; Genetics; MPQ; MRI; Orbitofrontal cortex; Personality; Twins