Intrinsic excitability of specific Ndnf-IN subclasses is preserved in Scn1a+/− mice during the chronic phase of DS pathogenesis. A–D, Representative traces from whole-cell current-clamp recordings of (A, C) NGFCs and (B, D) Canopy cells from the primary somatosensory cortex of P35–56 WT and Scn1a+/− mice in response to −60 pA, rheobase, and 100 pA over rheobase 600 ms square-wave current injections. E, F, Representative phase plots of APs in (E) NGFCs and (F) Canopy cells from P16–21 WT and Scn1a+/− mice. G, Relative proportions of Ndnf-IN classified as NGFCs versus Canopy cells in P35–56 WT and Scn1a+/− mice. H, I, F–I curves from whole-cell current-clamp recordings of (G) NGFCs (n = 17 cells from N = 8 WT mice; n = 27 cells from N = 9 Scn1a+/− mice) and (H) Canopy cells (n = 22 from N = 9 WT mice; n = 25 cells from N = 8 Scn1a+/− mice) from P35–56 WT and Scn1a+/− mice. The shaded regions indicate the 95% bootstrap CIs. Recordings were included in the analysis up to the maximum steady-state FF of the cell. Cumulative distribution functions (bottom) indicate the proportion of cells included in the analysis at each current injection. J–O, Summary data for (J) resting membrane potential, (K) input resistance, (L) rheobase, (M) AP threshold, (N) maximum rise slope, and (O) FF at 2× the rheobase current injection in NGFCs and Canopy cells from P35–56 Scn1a+/− mice and age-matched WT littermate controls. Error bars indicate standard deviation. Summary data for other measured intrinsic properties are listed in Table 3. Ninety-five percent CIs for all comparisons are listed in Table 4.