Contrasting roles of Ih and the persistent sodium current at subthreshold voltages during naturalistic stimuli.

The subthreshold activity of hippocampal CA1 pyramidal neurons is regulated by the persistent sodium current (INaP) and the h-current (Ih), carried by tetrodotoxin-sensitive sodium channels and hyperpolarization-activated cyclic-nucleotide-gated channels, respectively. Recently, Yamada-Hanff and Bean (J Neurophysiol 114: 2376-2389, 2015) used pharmacological methods to discern the roles of Ih and INaP at subthreshold voltages during naturalistic stimuli. We discuss these findings in the context of dorsoventral heterogeneity in the hippocampus and suggest further applications of the method.