Non-linear Membrane Properties in Entorhinal Cortical Stellate Cells Reduce Modulation of Input-Output Responses by Voltage Fluctuations
Fig 9
Block of voltage-dependent Na+ conductance increases sensitivity to membrane voltage fluctuations in stellate cells.
(A) Steady-state membrane input resistance measures for different holding voltages under control (black squares) and with 10 nM bath applied TTX (grey circles). (B) Example voltage traces from a stellate cell in response to a 100 ms depolarizing current step (i), as well as the average for the first 50 ms (ii) under control (black) and with TTX (grey). Inset (Bi) shows the average fraction of time the voltage trajectory spent above the mid-point for control and under bath applied TTX. (C) Representative examples of stellate cell voltage response to 100 ms long current steps of different amplitudes with and without membrane voltage fluctuations under bath applied TTX. (D) Average spike-probability curves in the presence of membrane voltage fluctuations under control (black) and 10 nM TTX (grey). Vertical lines indicate rheobase in the absence of voltage fluctuations for each condition. (E) Plots of average leftward shift (i) and sigmoid slope factor (ii) for control (black squares) and TTX (grey circles).