Figure 1.

Typical traces of rapid-onset spiking (RS) and delayed-onset spiking (DS) phenotypes of nucleus tractus solitarius neurons. Dotted traces are the command current steps and immediately below are the simultaneous recordings of the membrane potential and spiking. Recordings were made from nucleus tractus solitarius neurons in filtered air-exposed rhesus monkeys. Neurons were initially held at −50 mV and then a hyperpolarizing current was injected for 0.5 s in order to reach a membrane potential of −80 mV, followed by a depolarizing current injection (+100 pA). The RS phenotype displayed a spiking onset of ≤20 ms and the DS phenotype displayed a spiking onset of ≥100 ms.