Figure 1. HFS results in excess glutamate accumulation in the Q175FDN Het hippocampus that is not alleviated by ceftriaxone. A, Representative maximum projection images of the iGluSnFR response to HFS in WT-saline (Sal), Het-Sal, WT-Cef, and Het-Cef conditions. A bright-field image depicting the field of view containing the hippocampus is shown on the top left for the WT-Sal example. Scale bar, top right (top five images), 500 μm. The bottom panels represent the response to HFS over time (z-axis). Gray shading indicates the timing of HFS. Scale bar, bottom right, 1 s. B, Mean iGluSnFR responses (±SEM) in each group during HFS. The red box represents the portion of the response at stimulus offset used for the decay tau analysis in D. Gray shading above the response indicates SEM. The 1 s of HFS is indicated by the black horizontal bar above the response, and the shading underneath each response is representative of the area under the curve. Responses are normalized to the peak. C, Analysis of iGluSnFR sustain in WT and Het mice treated with Sal or Cef. D, Decay tau comparisons for each condition. E, Representative response at the end of stimulation showing the difference in iGluSnFR decay between WT-Sal and Het-Sal. F–H, Peak (F), time to reach the peak (G), and the area under the curve (AUC; H) in WT and Het mice treated with Sal or Cef. I, J, iGluSnFR responses (I) and peak values (J) in WT and Het slices exposed to 100 μm TBOA. All data are presented as the mean ± SEM. *p < 0.05, **p < 0.01, ***p < 0.001.