Morphogen-guided neocortical organoids with anteroposterior areal identity.

The human neocortex exhibits characteristic regional patterning (arealization) critical for higher-order cognitive function. Disrupted arealization is implicated in neurodevelopmental disorders (NDDs), but current neocortical organoid models largely fail to recapitulate this patterning, limiting mechanistic understanding. We establish a straightforward method for generating arealized organoids through short-term early exposure to anterior or posterior morphogens. These treatments created distinct anteroposterior (AP) signaling centers, supporting long-lasting polarization validated by spatial and single-cell RNA sequencing, which revealed area-specific molecular signatures matching the prenatal human cortex. To demonstrate utility, we modeled fragile X syndrome (FXS) in organoids with distinct AP identities. FXS organoids showed disrupted expression gradients along the AP axis, consistent with alterations in autism spectrum disorder, demonstrating how regional patterning defects may contribute to NDD pathology. Together, our study provides a robust platform for generating neocortical organoids with AP molecular signatures and highlights the importance of modeling NDDs using experimental platforms with neuroanatomic specificity.