Asymmetry in Signal Propagation between the Soma and Dendrites Plays a Key Role in Determining Dendritic Excitability in Motoneurons
Figure 5
Spatial dependence of cellular excitability on VADSDC and VASDAC.
All simulation conditions were identical to those used in Figure 4 except for systematically varying the values of the VADSDC and VASDAC. Note the inverse order of firing patterns with increasing distance compared to the physiological case (Figure 3). (A) – (D). F-Isoma relationships. (E) – (H). F-Gsyn relationships. The direction of black arrows indicates the ascending and descending phase of triangular current stimulation and change in Gsyn. The gray arrows indicate the current and Gsyn threshold for activating plateau potentials at different distances from the soma. At different locations, the VADSDC and VASDAC were {0.47, 0.6, 0.78, 0.876} and {0.65, 0.31, 0.18, 0.5}. The passive parameter values of the reduced model were Gm,S = {0.228, 0.183, 0.117, 0.067 mS/cm2}, Gm,D = {0.019, 0.079, 0.181, 0.276 mS/cm2}, GC = {0.099, 0.135, 0.204, 0.234 mS/cm2}, Cm,S = {1.644, 1.387, 0.766, 1.617 µF/cm2}, Cm,D = {0.134, 0.499, 1.373, 0.352 µF/cm2}. Parameter values in the parentheses are in the order of increasing distance from 200 to 1000 µm. Note that RN for all reduced models was set to be 1.29 MΩ.
