Abstract Vasocative-intestinal-peptide (VIP + ) and somatostatin (SST + ) interneurons are involved in modulating barrel cortex activity and perception during active whisking. Here we identify a developmental transition point of structural and functional rearrangements onto these interneurons around the start of active sensation at P14. Using in vivo two-photon Ca 2+ imaging, we find that before P14, both interneuron types respond stronger to a multi-whisker stimulus, whereas after P14 their responses diverge, with VIP + cells losing their multi-whisker preference and SST + neurons enhancing theirs. Additionally, we find that Ca 2+ signaling dynamics increase in precision as the cells and network mature. Rabies virus tracings followed by tissue clearing, as well as photostimulation-coupled electrophysiology reveal that SST + cells receive higher cross-barrel inputs compared to VIP + neurons at both time points. In addition, whereas prior to P14 both cell types receive direct input from the sensory thalamus, after P14 VIP + cells show reduced inputs and SST + cells largely shift to motor-related thalamic nuclei.

Developmental divergence of sensory stimulus representation in cortical interneurons