Development of the Avian Dorsal Thalamus: Patterns and Gradients of Neurogenesis.

The dorsal thalamus is a region of the diencephalon that relays sensory and motor information between areas of the brain stem and the telencephalon. Although a dorsal thalamic region is recognized in all vertebrates and believed to be homologous, little is known about how the regions within it evolved and whether some or all regions within the dorsal thalamus are homologous among different vertebrate species. To characterize the gradients and patterns of neurogenesis of the avian dorsal thalamus, a single application of a low dose of bromodeoxyuridine (BrdU) was delivered to each chick between embryonic day (E)3 and E8 (stages 21 and 34), and chicks were followed up to E8 or E10 (stage 34 or 36).