injection by smooth increases in action potential (AP) frequency with little change in AP threshold or amplitude (Zhang, 2004; Chang and Luebke, 2007). RS2 neurons show decreasing action-potential height and an increase in AP firing threshold whereas fast-accommodating (FA) RS neurons show similar changes in AP characteristics along with a robust accommodation in spiking. Intrinsically bursting (IB) neurons make up only a small percentage of neocortical pyramidal neurons and generate three to six spikes during threshold amounts of stimulation.
