Project Summary/Abstract Research Project: Behavioral Inhibition (BI) is a behavioral trait marked by enhanced discomfort during novel situations, such as going to a new place or meeting a new person. Though BI has been recognized as one of the strongest early indicators of social anxiety disorders later in childhood, many toddlers with BI do not go onto develop an internalizing disorder. To better understand the multiple outcomes of this risk marker the present study leverages a large (N = 326) pre-established longitudinal study to examine the underlying cognitive and neural processes of BI, specifically aberrant threat responding. To this end, I will assess the relation between BI (assessed at infancy and toddlerhood) and anxiety symptoms (assessed at 3 and 5 years of age; aim 1). Next, I will determine the link between attention- based neural response to threat and anxiety symptoms using a simultaneous functional Near- Infrared Spectroscopy (fNIRS) and eye tracking paradigm (aim 2). Finally, I will examine if and how individual differences in attention based neural responding moderates the expression of BI to predict childhood anxiety symptomology (aim 3). This investigation is of great relevance to public health because approximately one in three Americans will develop an anxiety disorder during their lifetime. Therefore, understanding core processes prior to and during the time when symptoms of anxiety disorders first emerge provides a tractable approach to disrupting anxiety trajectories across the lifespan. Training: The unparalleled training and mentorship provided by Sponsor Nelson (expert in developmental cognitive neuroscience) and Co-Sponsor Bosquet Enlow (expert in childhood anxiety disorders) at Boston Children’s Hospital/Harvard Medical school will bolster my methodological and theoretical knowledge in order to best prepare me to secure and successfully carryout a tenure track position at a research university.