Shawn Sorrells
University of Pittsburgh
I am fascinated by the development of neural circuits and processes that make human brain development unique. My current research is focused on the cellular basis of emotional development in children. I use traditional histology and light and electron microscopy in human samples combined with modern genetic tools and mouse models to test hypotheses generated from studying human development. I am studying nervous system development in human diseases like autism, epilepsy, and depression to learn fundamental characteristics of these disorders and to ultimately generate new therapeutic targets.
Immature amygdala excitatory neurons migrate and mature during adolescence in humans and mice
The amygdala is important for emotional and social behaviors that mature throughout childhood and adolescence. Across this timeframe, the total number of neurons in the human amygdala increases due to the delayed maturation of immature excitatory neurons that comprise ~20% of all human amygdala neurons. These neurons must therefore undergo large-scale neurodevelopmental processes throughout puberty including soma and dendritic expansions and, remarkably, axon growth and neuronal migration. We recently identified homologous neurons in mice that share molecular, developmental, and anatomical features with those in humans. In both species we find that these immature amygdala neurons are post-mitotic and remain dormant for weeks to months after their embryonic birth before maturing or migrating into neighboring brain regions during adolescence. The timing and location of this unique form of whole-cell structural plasticity suggests extended critical time-periods for the maturation of amygdala-dependent functions and emergence of related neuropsychiatric conditions.