Fig. 6
Fmr1−/y CA1 pyramidal neurons display increased excitability, which correlates with reduced synaptic inputs from the medial entorhinal cortex. A Representative traces from CA1 pyramidal neurons in the dorsal hippocampus from WT and Fmr1−/y rats, in response to depolarizing current injections (0–400 pA, 25 pA steps, 500 ms duration). B Action potential discharge in 500 ms compared to injected current for all recorded CA1 pyramidal neurons in WT and Fmr1−/y rats. Data shown as the mean response recorded per rat, with total number of neurons indicated. C The slope of the curve in (B) quantified for each neuron. Individual neuron data are shown overlain as filled circles, and the number of tested neurons shown below in parentheses. Average resting membrane potential (D) and input resistance (E), measured from the zero-current potential. Average data are plotted for the rheobase current (F), the voltage threshold (G), and medium afterhyperpolarization (mAHP) amplitude (H), the latter two measured from the first action potential at rheobase. I Visualization of the AIS in flattened confocal z-stacks after immunofluorescent labelling for AnkyrinG (AnkG, green pseudocolour) and merged with NeuN (blue pseudocolour) from WT and Fmr1−/y rats. Scale bars shown: 20 µm. J Quantification of AIS length, displayed as the average of individual animals. K Representative traces from cell attached recordings (upper traces) and whole cell recordings (lower traces) following stimulation of str. lacunosum moleculare to distal CA1, from WT and Fmr1−/y rats. EPSP data is shown as the average traces in response to stimulation intensities. L Average data for EPSP amplitude in response to the same stimulation intensities, delivered to the Schaffer collateral (SC), and M temporoammonic (TA) pathways. Average spike probability, measured in cell-attached recordings, for SC (N) and TA (O) paths. For L–O, all graphs display the result from 2-way ANOVA for genotype shown above the chart and number of tested neurons indicated in parentheses. All data is shown as mean ± SEM. Statistics shown as: ns—p > 0.05, *—p < 0.05, and ***—p < 0.001 from GLMM analysis, except panels B, K, L, M, N which are the result of 2-way ANOVA for genotype