Tangentially migrating cells differentiate into stratum griseum central neurons to form tectofugal visual pathway in the developing chick optic tectum.

Abstract

The optic tectum is the main visual processor of nonmammalian vertebrates and relays visual information from the eye to the telencephalon via the tectofugal pathway. In the development of the avian optic tectum, while the multipolar neurons are arranged by tangential migration, the behavior of individual cells in tangential migration, neural differentiation, and cell fate remain unclear. Here, we pursued the transition of tangentially migrating cells and their involvement in visual circuit formation during chick development. After tangential movement along the axons, the migrating cells relocated to the upper layers and turned back upon differentiation toward the multipolar neurons. The multipolar neurons are destined to differentiate into the stratum griseum central (SGC) neurons with the large dendritic field, which form the tectorotundal projection. Trans-synaptic virus labeling demonstrated that the tangentially migrating cells eventually participate in the tectofugal visual pathway. These results indicate that tangential migration is a crucial process in the formation of the tectofugal visual pathway during the development of the optic tectum.