PROJECT SUMMARY/ABSTRACT
The transition from adolescence to adulthood is a critical period of development characterized by significant
changes in social-emotional behavior. One of the central brain structures modulating this transition is the
amygdala. The development of the amygdala continues through adolescence, undergoing an expansion in size
and neuron number into early adulthood. These changes enable healthy social and emotional development, and
perturbations in amygdala development and maturation are linked a host of mental health disorders, most notably
autism spectrum disorders (ASD). However, the amygdala neuronal and circuit substrates underlying changes
coincident with this major life transition remain little understood.
In our published studies in humans, and our unpublished work in mice, we identified and characterized a unique
population of immature neurons in the paralaminar nucleus of the amygdala (PL). While these neurons are born
embryonically, they interestingly delay their maturation until adolescence when they differentiate into excitatory
neurons. Thus, the PL is well positioned to play a key role in the behavioral changes that are associated with the
transition from adolescence to maturity. The goal of our proposed studies is to understand the role of amygdala
late-maturing neurons in the circuitry, neuronal responsivity and behavioral transition that occurs during
adolescence. To test this, we will examine the dynamic circuit changes in input connectivity (Aim 1), neuronal
responsiveness (Aim 2), and the role the PL plays in the behavioral transition (Aim 3) from adolescence to early
adulthood.
Our discovery and characterization of PL neurons that undergo maturation coincident with adolescence suggests
a novel mechanism of brain plasticity during a critical stage of post natal development. Our proposed studies are
also an essential step to understanding the role late maturing PL neurons play in neuro-atypical brain function
associated with disorders of social cognition such as ASD and the long-term consequences of early life stress.