A new study published in PNAS examines how historical, social, and ecological processes have shaped urban segregation in Valdivia, southern Chile. Focusing on three key moments—European colonization, the 1960 earthquake, and current struggles to protect urban wetlands—the interdisciplinary research shows how socioeconomic inequality and historical legacies have influenced where people live and their access to nature and ecosystem services. The study also highlights how flooding disproportionately affects lower-income neighborhoods, where wetlands can provide critical protection against excess water. By applying the concept of the “Ecology of Segregation” to a city in the Global South, the researchers highlight the importance of inclusive urban planning, environmental justice, and the protection of urban wetlands.

Salk neuroscientists identify and characterize new region in the brain’s fear circuit called the amygdalostriatal transition zone (ASt). ASt neurons fire with more strength and for longer than the amygdala, which has historically been considered the brain’s fear center. Findings explain why fear responses like freezing can last so long and point to therapeutic innovations for disorders like PTSD, anxiety.