“How we end up with similar circuitry was more flexible than I would have expected,” Zaremba said. “You can build the same circuits from different cell types.”
Zaremba and her team also found that in the bird pallium, neurons that start development in different regions can mature into the same type of neuron in the adult. This pushed against previous views, which held that distinct regions of the embryo must generate different types of neurons.
In mammals, brain development follows an intuitive path: The cells in the embryo’s amygdala region at the start of development end up in the adult amygdala. The cells in the…