Objective: At the broadest level, self-regulation refers to a
range of separate, but inter-related, processes (e.g., working memory,
inhibition, emotion regulation) central for the regulation of cognition,
emotion and behaviour that contribute to a plethora of health and mental health
outcomes. Self-regulation skills develop rapidly in early childhood, but their
neurobiological underpinnings are not yet well understood. The amygdala is one
key structure in negative emotion generation that may disrupt self-regulation.
In the current study, we investigated the associations between neonatal
amygdala volumes and mother-reported and observed child self-regulation during the
first three years of life. We expected that larger neonatal amygdala volumes
would be related to poorer self-regulation in children.

Method: We measured amygdala volumes from MRI performed at age M=3.7±1.0. We examined
the associations between the amygdala volumes corrected for intracranial volume
and a) parent-reported indicators of self-regulation at 6, 12 and, 24 months
(N=102) and b) observed, task-based indicators of self-regulation (working
memory and inhibitory control) at 30 months of age in a smaller subset of
participants (N=80).

Results: Bilateral neonatal amygdala volumes predicted poorer working memory at
30 months in girls, whereas no association was detected between amygdalae and
inhibitory control or parent-reported self-regulation. The left amygdala by sex
interaction survived correction for multiple comparisons.

Conclusions: Neonatal amygdala volume is associated with working
memory, particularly among girls, and the association is observed earlier than
in prior studies. Moreover, our findings suggest that the neural correlates for
parent-reported, compared to observed early life self-regulation, may differ.