Fig. 5.

Impaired Schaffer Collateral LTP in Fgf14^−/− mice. (A) Representative recordings from a hippocampal slice from a WT mouse exhibit stable fEPSP baseline responses to stimuli applied every minute for 20 min (labeled Baseline, 20 consecutive traces superimposed, red line indicates the first response). 55–60 min after 3 applications of theta burst stimuli (3TB), the fEPSP slope remains significantly potentiated relative to the baseline responses, indicating successful induction and maintenance of LTP (middle panel labeled 55–60 min after 3TB). The fEPSP shows a normally graded increase in amplitude with increasing stimulus intensity (0–250 mA stimulus, labeled Input/Output). (B) Representative recordings from a hippocampal slice from an Fgf14^−/− mouse exhibit stable baseline responses (Baseline), normal input output responses (Input/Output), but failed to maintain LTP (55–60 min after 3TB). (C) Cumulative data from LTP experiments from all slices were combined by normalizing fEPSP slopes to the baseline responses. Numbers in parentheses indicate when representative traces in A and B were obtained (1, Baseline; 2, 55–60 min after 3TB). The arrow indicates when 3TB were applied. Approximately 58% potentiation of the baseline response was observed in the WT slices (open circles). Although there is initially some post 3TB potentiation, LTP is not maintained in slices from Fgf14^−/− mice (closed circles). (D) LTP compared between WT and Fgf14^−/− slices at 55–60 min after 3TB (corresponding to 2 in C) demonstrates impaired LTP maintenance in Fgf14^−/− mice (p<0.001 one-way ANOVA). Scale bar, 0.5 mV and 5 ms. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)