Figure 5.
Example of a hypoexcitable hG93A-SOD1 motoneuron. (A) Hypoexcitable hG93A-SOD1 motoneurons cannot sustain repetitive firing in response to slow injected current ramps (0.6 nA/s). (B) The PIC from the same motoneuron was significantly smaller than those in hG93A-SOD1 motoneurons that are capable of repetitive firing. (C) This hypoexcitable motoneuron could generate only a single action potential (red trace) during a prolonged (800 ms) 1 nA depolarizing current step, and stayed hypoexcitable (black trace) even when input current was doubled to 2 nA. (D) In contrast to hypoexcitable motoneurons, wild-type motoneurons can fire repetitively under 1 nA, 800 ms depolarizing current step.