On the Spectrum

General introduction
positive on one or more aspects of a multifaceted screening procedure for ASD in order to
confirm this diagnosis.
Chapter 3 of this thesis additionally involves data collected within the Raine Study, an
Australian cohort study of women recruited prior to 18 weeks gestation from the public
antenatal clinic at King Edward Memorial Hospital or surrounding private clinics, between
May 1989 and November 1991 (Newnham, Evans, Michael, Stanley and Landau 1993). As
part of a trial investigating effects of prenatal ultrasound, women underwent one or more
ultrasound measurements during pregnancy. To these women, 2,868 children were born and
available for postnatal follow-up, including behavioral assessments.
1
Outline
This thesis is divided into two parts. Part I focuses on various aspects of the neurobiology of
autism, utilizing continuous trait measures. In chapter 2, we describe several characteristics
of cortical morphology in children with autistic traits and in chapter 3, we focused on prenatal
brain growth using ultrasound measurements. In chapter 4, we studied white matter integrity
and chapter 5, we investigated dynamic characteristics of resting state connectivity in children
with autistic traits.
The second part of this thesis focuses on specific cognitive and neurobiological
characteristics of children with internalizing and externalizing problems. In chapter 6,
we studied specific cognitive problems in children with internalizing, externalizing and
dysregulation problems. In chapter 7, we studied brain morphology related to internalizing
behavior in young children. Finally, in chapter 8, we discuss the main findings of these studies
in the context of recent literature and we discuss methodological considerations, as well as
implications of these studies for further research and clinical practice.
17