Figure 5. Changes of membrane properties of WT versus DKO SGNs isolated from cochlear apex and base at different ages (1- 3- 4-5- 6- and 9-month). (A) The resting membrane potential (RMP) of SGNs was significantly altered at different stages in development. (B) Changes in AP amplitudes of WT and DKO SGNs from apical and basal cochlea are summarized. (C) Amplitude of afterhyperpolarization (AHP) measured and summarized (*p < 0.05; **p < 0.01; n = number of SGNs are indicated). For these data, significant differences between genotypes were determined using the unpaired two-tailed t-test. Other action potential parameters such as latency and duration were measured but not shown (we did not identify any significant changes in action potential latency and duration in WT versus DKO at different stages of development and location in the cochlea).