Crossing over

Two Yale neuroscientists have discovered a pathway, apparently unique to humans, that guides neurons between different brain regions. “Disregarding boundaries between major brain divisions is unusual,” said principal investigator Pasko Rakic, M.D., Ph.D., chair of the Department of Neurobiology and the Dorys McConnell Duberg Professor of Neuroscience, “and could explain how parts of the cerebral cortex associated with the highest cognitive functions may have coordinated their growth with subcortical structures during human brain evolution.” Rakic and graduate student Kresimir Letinic found that attractive and repulsive molecules directed neuronal stem cells from the ganglionic eminence to the diencephalon. They published their findings in the September issue of Nature Neuroscience.