(A) Density ratios of KO/WT synapses containing SYNPO, a marker of mature dendritic spines, reveal no significant change in total SYNPO synapse density (n = 6 pairs).
(B) Analysis of specific synaptic classes reveals significant synapse density changes mediated by FMRP loss in layer 4 VGluT1 synapses and layer 5 VGluT2 synapses.
(C and D) Fenobam treatment normalizes to WT SYNPO-containing synapse density across all classes (n = 6 pairs).
(E) Fenobam application in WT animals induces a density increase in layer 5 synapses (n = 5 pairs).
(F) Fenobam-induced SYNPO synapse density increase is specific to VGluT1 class synapses. Error bars, SE. Significance is calculated using paired t tests, and the p values are adjusted via FDR test. q < 0.05.