What we study

The developing brain must assemble brain circuits that generate social behavior, and these circuits are surprisingly dynamic. We study how the young brain builds and re-tunes neural circuits across two sensitive windows: infancy, when an animal is fully dependent on a caregiver, and adolescence, when relationships with peers can shape mental and physical health for years to come.

A recurring theme is that social behavior is regulated much like hunger or thirst — all needs that are regulated by the brain. When young animals are deprived of social contact, the brain registers a state of social need and boosts the drive to reconnect.

Across these projects we treat behavior as a developmental phenomenon: the same brain circuit can mean different things at different ages.

The classic Krogh principle states that some questions can only be answered in the right organism. To this end, we have spent more than a decade establishing the nine-banded armadillo (Dasypus novemcinctus) as a modern research model in Yale’s Department of Comparative Medicine — home to what we believe is the only academic armadillo research colony of its kind. A member of the ancient Xenarthra lineage, the armadillo has two extraordinary features that make it a rare window into how life begins:

1. Reproduction and suspended development. Like many mammals, the armadillo can pause its pregnancy through embryonic diapause (delayed implantation) — but it does so to an extreme found nowhere else, holding an early embryo in a suspended state for years. We study how development is halted and later reawakened, and the molecular signals from the embryo, uterus, ovaries, and nervous system that place life on hold. These mechanisms bear on human reproductive challenges such as infertility and pregnancy loss, and on broader questions of cellular dormancy and aging.

2. The origins of individuality. The armadillo always gives birth to genetically identical quadruplets: a single fertilized egg reliably splits into four embryos (obligate polyembryony), essentially unique among mammals. This provides a natural experiment to test how four individuals arise from one genome. We probe this question with single-cell and spatial genomics, epigenomics, lineage tracing, and stem-cell models, with implications reaching into stem-cell biology and the neurobiology of individuality.