Neurodevelopmental disorders such as autism spectrum disorders (ASD) likely arise well before a clinical diagnosis is made. Longitudinal studies in infants with and without familial risk for ASD provide the opportunity to identify biomarkers that predate later ASD symptoms. Here we report how Early Stage Researchers are collaborating to use novel multi-modal methods within such cohorts to reveal typical and atypical mechanisms of early development. The first presenter will start at birth, examining maturation of synchronous fMRI activity in the social brain network in neonates at-risk of ASD. In the second presentation, we look at responses to social stimuli in 8-month-old infants who later develop ASD and explain how this data can be used to predict later diagnostic outcome in classifier models. The third presenter will then report on the association between functional EEG connectivity in at-risk infants at 14-months and restricted and repetitive behaviours in ASD. Finally, the last talk will examine 2-4 year-old toddlers recently diagnosed with ASD and explore the association between autonomic arousal (heart rate and heart rate variability) and cognitive and social skills. Together, with the discussant, we will examine how these findings may have clinical meaning, both for early diagnosis and targeting novel treatments.