Early lineage divergence segregates sensory-related and motor-associative identities in the thalamus [Spatial Transcriptomics E17]

Here, we generate a spatiotemporal single-cell multiomic and spatial transcriptomic atlas of the embryonic mouse thalamus, combined with barcoding-based lineage tracing. We identify two major glutamatergic lineages, sensory-related and motor-associative, each governed by different gene regulatory programs and temporal dynamics.

These lineages arise from spatially and molecularly distinct progenitor domains, revealing an early segregation of functional identities. Within the sensory lineage, we resolve branching sensory trajectories leading to first-order visual and somatosensory neurons, both emerging from a shared higher-order-like state. Using in silico predictions and in vivo perturbation, we identify Sp9 as a key regulator of visual thalamic fate.