Figure 4.
Functional connection probability functions of genotype. A, The total proportion of neuron pairs with synaptic connections is shown as a function of either presynaptic or postsynaptic genotype for Fmr1 mosaics. Error bars show the 95% confidence intervals of the proportions. The asterisk indicates that the raw number of functional connections was significantly reduced in neuron pairs with Fmr1 KO presynaptic neurons relative to pairs with Fmr1 WT presynaptic neurons (p < 0.05, Pearson's χ2 test) (see Results and Materials and Methods). At the same time, the proportion of functional connections was not significantly affected by the postsynaptic Fmr1 genotype. Note that because GFP neurons were selected for recordings at a much greater frequency than they occurred in the slices, the absolute connectivity rates calculated from these recordings do not necessarily reflect the overall mean connectivity of the slices. B, The total proportion of neuron pairs with synaptic connections is shown as a function of either presynaptic or postsynaptic GFP labeling in control mosaics (see Results) (total n = 58 pairs). There was no difference in the percentage of functional connections in control mosaics caused by either presynaptic or postsynaptic GFP labeling status.