Figure 1.

AP shape and metabolic efficiency vary with dendrite area in model I. (A) Schematic of model I. There are no active channels in its dendritic chamber. Red arrows indicate the direction of ionic current. We set coupling conductance to $g_{\mathrm{\text{c}}}=0.5\mathrm{\text{mS}}/\mathrm{\text{c}}{\mathrm{\text{m}}}^{\mathrm{\text{2}}}$ and vary morphological parameter p. (B) Responses of membrane voltage V_S recorded from the soma with different values of p, which are indicated on the top of each panel. (C) Both height and half-width of the AP increase as a function of p. (D) Top panel: total Na⁺ load Q_total during an AP is plotted as a function of p. Note that Q_total reaches a maximum with moderate value of p. Bottom panel: minimal Na⁺ load Q_min increases as a function of p. (E) Na⁺ entry ratio decreases as a function of p. (F) Overlap Na⁺ load Q_overlap during an AP is plotted as a function of p. Similar to Q_total, Q_overlap also reaches a maximum with moderate value of p. Dendritic input is $I_{\mathrm{\text{D}}}=3\mu \mathrm{\text{A}}/\mathrm{\text{c}}{\mathrm{\text{m}}}^{\mathrm{\text{2}}}$.