Figure 1. Electrophysiological characteristics of paraventricular nucleus (PVN) neurons.

Different types of PVN neurons are distinguished by their response to incremental depolarizing pulses delivered at a hyperpolarized potential (top trace). Type I putative magnocellular neurons express a transient outward rectification caused by I _A potassium current reflected as a delay in the onset to the first action potential (arrow). Type II putative parvocellular neurons lack the outward rectification and delay in response to the same current stimuli.