Whisker deprivation started at P13 disrupts maturation of the VPm relay synapse. A, B, Synaptic currents recorded from two neurons in the deprived (A) and spared (B) VPm at P17 following whisker deprivation started at P13. For each cell, synaptic currents at +40 and −70 mV were obtained at the same stimulation intensity. C, The AMPAR/NMDAR ratio obtained from neurons at P16–P18 following whisker deprivation at P13. The ratio obtained from deprived VPm neurons (n = 24; hatched) was significantly smaller than that from spared neurons (n = 27; empty) or neurons in normal mice at the same age (n = 23; gray) (**p < 0.002, Kruskal–Wallis test). D, The peak amplitude of the maximal EPSC-AMPAR and EPSC-NMDAR for deprived (hatched), spared (empty), and normal (gray) VPm neurons at P16–P18 (*p < 0.03, Kruskal–Wallis test). E, Decay constant of EPSC-NMDAR for deprived (hatched), spared (empty), and normal (gray) VPm neurons at P16–P18. F, Paired-pulse ratios of EPSC-AMPAR at interstimulus intervals of 50 and 100 ms.