Cortical representation of the common fur of mystacial pad is situated outside postero-medial barrel subfield (PMBSF) in rat primary somatosensory cortex. Following neonatal vibrissectomy, stimulation of the common fur activates the neurones in PMBSF. We examined if sparing of one mystacial vibrissa from the neonatal ablation, which results in a very extensive increase of its cortical representation, would prevent the invasion of the common fur inputs into the PMBSF. The cortical representations were mapped with 2-deoxyglucose (2DG). It was found that six weeks after neonatal vibrissectomy sparing C3 vibrissa and common fur inputs were represented in the PMBSF. Their representation shifted from its normal location into the barrel field. This effect was observed in cortical layers II/III, IV and V.