Forebrain patterning networks: which signaling families interact to pattern the forebrain along dorsal–ventral and rostrocaudal axes and establish midline structures?

Forebrain patterning networks: which signaling families interact to pattern the forebrain along dorsal–ventral and rostrocaudal axes and establish midline structures?

• A. SHH, BMP, and WNT
• B. FGF, Notch, and JAK/STAT
• C. RA, FGF, and EGF
• D. BMP, TGF-beta, and Notch

Answer: (A)

Forebrain patterning relies on opposing morphogen signals that establish cell identities along two axes—dorsal versus ventral and anterior versus posterior—while also setting up midline regions. The trio SHH, BMP, and WNT best fits this role. Sonic hedgehog released from ventral midline/floor plate drives ventral telencephalic identity and midline structures, creating the opposite side of the axis from dorsal signals. BMP and WNT come from dorsal regions and push dorsal identities, shaping the forebrain’s dorsal forebrain territories and helping define rostrocaudal patterning through their gradients and interactions with SHH. Together, these pathways coordinate the broad map of forebrain regions and the midline organization. Other pathways listed contribute to neural development in different ways—proliferation, timing of neurogenesis, or later differentiation—rather than serving as the primary, coordinating dorsal-ventral and rostrocaudal patterning signals for the forebrain.

Forebrain patterning relies on opposing morphogen signals that establish cell identities along two axes—dorsal versus ventral and anterior versus posterior—while also setting up midline regions. The trio SHH, BMP, and WNT best fits this role. Sonic hedgehog released from ventral midline/floor plate drives ventral telencephalic identity and midline structures, creating the opposite side of the axis from dorsal signals. BMP and WNT come from dorsal regions and push dorsal identities, shaping the forebrain’s dorsal forebrain territories and helping define rostrocaudal patterning through their gradients and interactions with SHH. Together, these pathways coordinate the broad map of forebrain regions and the midline organization.

Other pathways listed contribute to neural development in different ways—proliferation, timing of neurogenesis, or later differentiation—rather than serving as the primary, coordinating dorsal-ventral and rostrocaudal patterning signals for the forebrain.