title: A preliminary study of orbitofrontal activation and hypersociability in Williams Syndrome.
abstract: Individuals with Williams syndrome (WS) demonstrate an abnormally positive social bias. However, the neural substrates of this hypersociability, i.e., positive attribution bias and increased drive toward social interaction, have not fully been elucidated. METHODS: We performed an event-related functional magnetic resonance imaging study while individuals with WS and typically developing controls (TD) matched positive and negative emotional faces. WS compared to TD showed reduced right amygdala activation during presentation of negative faces, as in the previous literature. In addition, WS showed a unique pattern of right orbitofrontal cortex activation. While TD showed medial orbitofrontal cortex activation in response to positive, and lateral orbitofrontal cortex activation to negative, WS showed the opposite pattern. In light of the general notion of a medial/lateral gradient of reward/punishment processing in the orbitofrontal cortex, these findings provide an additional biological explanation for, or correlate of positive attribution bias and hypersociability in WS.
authors.affiliation: Department of Neuropsychiatry, Showa University School of Medicine, Tokyo, Japan; Center for Interdisciplinary Brain Sciences Research (CIBSR), Stanford University, School of Medicine, Stanford, CA, USA.
authors.forename: Masaru
authors.initials: M
authors.lastname: Mimura
authors.forename: Fumiko
authors.initials: F
authors.lastname: Hoeft
authors.forename: Motoichiro
authors.initials: M
authors.lastname: Kato
authors.forename: Nobuhisa
authors.initials: N
authors.lastname: Kobayashi
authors.forename: Kristen
authors.initials: K
authors.lastname: Sheau
authors.forename: Judith
authors.initials: J
authors.lastname: Piggot
authors.forename: Debra
authors.initials: D
authors.lastname: Mills
authors.forename: Albert
authors.initials: A
authors.lastname: Galaburda
authors.forename: Julie R
authors.initials: JR
authors.lastname: Korenberg
authors.forename: Ursula
authors.initials: U
authors.lastname: Bellugi
authors.forename: Allan L
authors.initials: AL
authors.lastname: Reiss