Migrating Pyramidal Neurons Require DSCAM to Bypass the Border of the Developing Cortical Plate

Area of Science:

• Neuroscience
• Developmental Biology
• Cellular Biology

Background:

• Mammalian neocortex development involves outward migration of pyramidal neurons.
• Understanding how migrating neurons bypass predecessors for proper cortical expansion is limited.
• Down syndrome cell adhesion molecule (DSCAM) is implicated in neurodevelopmental disorders.

Purpose of the Study:

• To investigate the role of DSCAM in the migration and positioning of pyramidal neurons.
• To elucidate the mechanism by which DSCAM facilitates the expansion of upper cortical layers.

Main Methods:

• Ex vivo time-lapse imaging of neuronal migration in developing cortices.
• Analysis of DSCAM-deficient cortical development.
• Investigation of DSCAM's interaction with N-cadherin mediated cell adhesion.

Main Results:

• DSCAM is essential for migrating neurons to bypass postmigratory predecessors and expand the cortical plate.
• DSCAM deficiency leads to premature termination of migration, resulting in thinner upper cortical layers.
• DSCAM weakens N-cadherin mediated cell adhesion, enabling neuronal traversal of the cortical plate border.

Conclusions:

• DSCAM plays a critical role in the migratory termination and final positioning of pyramidal neurons.
• Dysfunction of DSCAM may contribute to brain abnormalities observed in disorders with thinner upper cortical layers.
• DSCAM's mechanism involves modulating cell adhesion to facilitate neuronal migration dynamics.