Fig. 4: Increased synaptic surface expression of AMPAR and basal excitatory transmission in hippocampal Fmr1^R138Q neurons.

a, b Super-resolution STED images of surface-expressed GluA1 and GluA2 (STED, green) in postsynaptic Homer1 sites (confocal, red) of TTX-treated WT and Fmr1^R138Q hippocampal neurons. Scale bar, 500 nm. c, d Quantification of (a) and (b). Box plots indicate median (middle line), 25^th, 75^th percentile (box), and min to max values (whiskers) obtained for the mean surface GluA1 and GluA2 fluorescence intensity (c) and nanodomains (d) in WT and Fmr1^R138Q neurons. N = 17–30 (WT) and 15–30 (Fmr1^R138Q) neurons were analyzed from three biologically independent experiments with a total of dendritic spines analyzed ranging from 878 to 4246. Unpaired t test. ***p < 0.0001; **p = 0.0011. e–k mEPSCs recordings from acute hippocampal slices obtained from PND90 WT and Fmr1^R138Q littermates. Quantification shows the mean values ± s.e.m. (e, g) and cumulative curves ± s.e.m. (f, h) of mEPSC amplitude and frequency. N = 10–11 neurons per genotype from three independent experiments. Unpaired t test. ns not significant. *p = 0.0111. i Example traces of WT and Fmr1^R138Q single events. j Computed Tau rise and decay. k Representative traces of mEPSC recordings from WT and Fmr1^R138Q hippocampal slices. Source data are provided as a Source Data file.