Open Access Open Badges Study protocol

Study protocol: Imaging brain development in the Childhood to Adolescence Transition Study (iCATS)

Julian G Simmons12, Sarah L Whittle3, George C Patton26, Paul Dudgeon1, Craig Olsson25, Michelle L Byrne1, Lisa K Mundy24, Marc L Seal26 and Nicholas B Allen1*

Author Affiliations

1 Melbourne School of Psychological Sciences, The University of Melbourne, VIC 3010, Australia

2 Murdoch Childrens Research Institute, Melbourne, Australia

3 Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne, 1-100 Grattan Street, Parkville, VIC 3010, Australia

4 Centre for Adolescent Health, The Royal Children’s Hospital, Melbourne, Australia

5 Deakin University, Melbourne, Australia

6 Department of Paediatrics, The University of Melbourne, Melbourne, Australia

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BMC Pediatrics 2014, 14:115  doi:10.1186/1471-2431-14-115

Published: 30 April 2014



Puberty is a critical developmental phase in physical, reproductive and socio-emotional maturation that is associated with the period of peak onset for psychopathology. Puberty also drives significant changes in brain development and function. Research to date has focused on gonadarche, driven by the hypothalamic-pituitary-gonadal axis, and yet increasing evidence suggests that the earlier pubertal stage of adrenarche, driven by the hypothalamic-pituitary-adrenal axis, may play a critical role in both brain development and increased risk for disorder. We have established a unique cohort of children who differ in their exposure to adrenarcheal hormones. This presents a unique opportunity to examine the influence of adrenarcheal timing on brain structural and functional development, and subsequent health outcomes. The primary objective of the study is to explore the hypothesis that patterns of structural and functional brain development will mediate the relationship between adrenarcheal timing and indices of affect, self-regulation, and mental health symptoms collected across time (and therefore years of development).


Children were recruited based upon earlier or later timing of adrenarche, from a larger cohort, with 128 children (68 female; M age 9.51 years) and one of their parents taking part. Children completed brain MRI structural and functional sequences, provided saliva samples for adrenarcheal hormones and immune biomarkers, hair for long-term cortisol levels, and completed questionnaires, anthropometric measures and an IQ test. Parents completed questionnaires reporting on child behaviour, development, health, traumatic events, and parental report of family environment and parenting style.


This study, by examining the neurobiological and behavioural consequences of relatively early and late exposure to adrenarche, has the potential to significantly impact our understanding of pubertal risk processes.

Puberty; Hormones; Adrenarche; Adolescence; Brain development; Protocol; MRI; Gonadarche