Figure 5. Blocking I_A does not alter action potential discharge properties of non-burst and typical burst TRN neurons.

Typical burst: in this neuron, the depolarizing current step produces clear burst discharge ring atop an LTS. In the presence of 4-AP (0.5 mm), the burst discharge persists. Atypical burst: in this neuron, the depolarizing current step produces the atypical burst discharge consisting of an initial sharp action potential followed by broader transient depolarizations (see inset). In 4-AP, a similar discharge pattern is observed; however, the last transient depolarization (arrow in inset) has a longer duration. Non-burst: from a membrane potential of −80 mV, depolarizing current steps in control solution produced no burst discharge in this neuron. In the presence of 4-AP, the depolarizing current step still produces only tonic discharge with a shorter latency to the first action potential. Inset scale: 20 mV, 20 ms.