Figure 6. Fast dynamic-clamp (FDC) of Na⁺ current in L5 pyramidal neurons.

A, experimental set-up for injecting artificial G_NaT, G_NaP and G_K. A pyramidal neuron was recorded in double whole-cell configuration in a cortical slice. V_m was measured by electrode 1 and the dynamic current, I_Dyn, was injected by electrode 2. B, validation of FDC in a regular spiking neuron. Top, APs were evoked by a step of depolarizing current. Middle, TTX blocked firing. Bottom, addition of the simulated G_NaT, G_NaP and G_K with FDC (I_Dyn) re-established the discharge. C and D, FDC in a bursting neuron. Effects of shifting the activation of I_NaP (SA_NaP) by 6.5 mV and the inactivation of I_NaT (SI_NaT) by 6 mV on the number of spikes evoked by a depolarizing step (C) and the latency of the first AP (D). Each data point corresponds to a single neuron.