Figure 7.

Intrinsic membrane properties of the PD axon, tested in two-electrode current clamp in the absence of centrally generated activity. A, Depolarizing sag potential (black arrow) and rebound depolarization (white arrow) in response to hyperpolarizing current injection. The sag potential substantially reduced by CsCl, but the rebound to some degree persists. B, Spike frequency adaptation and sAHP in response to depolarizing current injections. The top panel shows the instantaneous spike frequency for each spike. Black arrows indicate the reduction in spike amplitude. The inset shows the sAHP (white arrow) from the voltage and time range indicated in the response to the third square pulse (dashed box).