FIGURE 5.

(A) Intracellular recording observed for an HPC in vitro in zero-calcium condition with different depolarizing DC currents applied intracellularly. (B) Model cell behavior at different DC depolarizing currents. Both show that the addition of a depolarizing DC current results in a transition from triplet activity, to doublets and then singlets. (C) A complex activity with varying burst patterns can be observed for the model with 0.04-nA depolarizing DC current. (D) The spiking frequencies both in vitro (square) and in the model (circle) increases as the DC stimulus are increased. The spiking frequency is calculated as the average spiking rate over time. The variance for frequency in vitro is 2; for the model, <0.2. The suppression of spike firing occurs at large enough depolarizing or hyperpolarizing currents. In the upper part of D, the typical regions of different spiking number per burst are also indicated. Here 1S, 2S, and 3S mean singlet, doublet, and triplet modes of activity, respectively. The activity of a two-spike burst followed by a three-spike burst is simply indicated by 5S. CS refers to the complex burst mode.