TWIK-1 knockdown in dentate granule cells affects signal input-output properties of the cells. (A) Representative traces from spiking probability measurements (left panel). Synaptic responses evoked by 200 μA stimulation of perforant path are shown. Input-output properties of dentate granule cells (right panel). Plotted are the values of spiking probability in naïve (n = 16 cells, N = 3 mice), Sc shRNA (n = 16 cells, N = 3 mice) or TWIK-1 shRNA (n = 16 cells, N = 3 mice) expressing dentate granule cells. The solid line is a logistic fit of the data plots. (B) Representative traces from spiking probability measurements (left panel). Traces with multiple spikes are shown in red. Averaged input-output properties of the subpopulation of the burst discharging cells (right panel). Plotted are the averaged values of probability of firing more than one spike per eEPSP in TWIK-1 shRNA or Sc shRNA expressing cells. (C) Representative traces of ten evoked EPSP responses in Sc shRNA and TWIK-1 shRNA expressing dentate granule cells (stimulation intensity was 350 μA) (left panel). The dotted lines indicate RMP, the voltage threshold for the first AP (Vth1) and the voltage threshold for the second AP (Vth2) in the burst response. Traces containing the second spike are shown in red. Summary bar graph for averaged depolarization level after the termination of the first AP in Sc shRNA and a population of TWIK-1 shRNA expressing cells with multiple spikes (right panel). The dotted lines show the threshold levels for the first (Vth1) and the second (Vth2) AP during a single EPSP. Number of cells are shown within the bars. All data are represented as mean ± S.E.M; *P < 0.05, **P < 0.01 Student's unpaired t-test.