Figure 1: Normal visual cortical functions in PV-Mecp2^−/y mice.

(a) Fluorescence images showing V1 sections stained for the nucleus (4′,6-diamidino-2-phenylindole, DAPI), MeCP2 and parvalbumin (PV). Right: higher resolution images of the rectangle area. Scale bars, 100 and 20 μm for low and high resolution images, respectively. (b) Plots of the density of PV cells (black) and the percentage of MeCP2-immunostaining cells in total PV cells (magenta) in the V1 of different types of mice at P30 (upper) and over the postnatal development (P20–60) in PV-Cre and PV-Mecp2^−/y mice (bottom). (c) Contralateral RFs of example V1 binocular cells recorded in the WT and PV-Mecp2^−/y mice at P30. Peri-stimulation histograms (PSTHs) of spike rate in response to flashing bright square (about 10°) at discrete positions in an 8 × 8 grid were shown. Red lines outline the approximate size of the RFs. (d) The mean RF size of V1 binocular cells recorded in WT (black), PV-Cre (red), flox-Mecp2 (blue) and PV-Mecp2^−/y (green) mice. (e) Plot of V1 cell RF-centre azimuths relative to the vertical meridian (M–L position) from WT, PV-Cre, flox-Mecp2 and PV-Mecp2^−/y mice. (f) PSTH and polar plots of spike rates evoked by drifting gratings at eight different orientations (45° step; spatial frequency 0.002 cycle per degree; temporal frequency 2 Hz) of example V1 cells recorded from WT (black) and PV-Mecp2^−/y (red) mice. Blue dashed lines: stimulation duration. The numbers in blue represent spike rates. (g) Cumulative percentage distribution of orientation selectivity indices (OSIs) for all recorded V1 cells from WT, PV-Cre, flox-Mecp2 and PV-Mecp2^−/y mice. No significant difference was found between the data from paired genotypes (Kolmogorov–Smirnov test). (h) The dependence of spike rate on the spatial frequency of drifting gratings of V1 cells from four genotypes. Average data are presented as mean±s.e.m.