Bulk RNA sequencing of intracortically-projecting neurons at P10

Distinct subtypes of intracortically-projecting neurons (ICPN) are present in all layers, allowing propagation of information within and across cortical columns. How the molecular identities of ICPN relate to their defining anatomical and functional properties is unknown. Here we show that the transcriptional identities of ICPN primarily reflect their broad axonal projections rather than their date of birth or laminar position. Thus, conserved circuit-related transcriptional programs are at play across cortical layers, which may preserve canonical circuit features across development. We performed bulk RNA sequencing of P10 layer 4 Tomato+ spiny stellate neurons, and retrogradely labeled callosal projection neurons from deep and superficial layers of the neocortex.