Fig. 2.
Response of neuron LP2 to current-clamp stairstep protocol. Bias current was applied to reach and maintain a nominal membrane potential of −100 mV for 60 s, followed by 60 s of a 0.5-Hz fixed-amplitude square-wave pulse train added to the bias current (the actual steady-state potential achieved was used in all calculations). This process was repeated at 6 increasingly depolarized potentials. In this experiment the entire stairstep was repeated for 2 additional cycles. Inset: 3 cycles of the neuron's response during the pulse train at −50 mV. Pulse train response amplitude was greater at −95 mV than at −50 mV [the membrane potential at which capacitance measurements are typically made (Golowasch et al. 2009)], indicating that input resistance (RN) was greater at −95 mV.