Asymmetry in Signal Propagation between the Soma and Dendrites Plays a Key Role in Determining Dendritic Excitability in Motoneurons
Figure 3
Cellular excitability of the anatomical (blue) and reduced (red) model with different locations of PIC channels in the dendrites.
The neuron models and stimulation protocols were the same as those used in Figure 2(H) & (I) except for variation of PIC channel location in the dendrites. (A) – (D). Firing rates (F) in response to triangular current stimulation to the soma (Isoma). (E) – (H). Firing rates (F) in response to triangular variation of maximum conductance (Gsyn) of excitatory synaptic receptors in the dendrites. 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. Note the negative relation between the distance and input threshold. At different locations in the dendrites, the three VA factors were VASDDC = {0.91, 0.77, 0.69, 0.63}, VADSDC = {0.96, 0.79, 0.57, 0.38} and VASDAC = {0.65, 0.31, 0.18, 0.12}; the density of Ca PIC channels were GCa,L = {1.14, 1.27, 1.95, 4.1 mS/cm2} in the anatomical and {0.11, 0.122, 0.132, 0.189 mS/cm2} in the reduced model; the passive parameter values of the reduced model were Gm,S = {0.078, 0.132, 0.174, 0.2 mS/cm2}, Gm,D = {0.179, 0.143, 0.1, 0.07 mS/cm2}, GC = {0.918, 0.244, 0.114, 0.06 mS/cm2}, Cm,S = {0.609, 1.077, 1.211, 1.302 µF/cm2}, Cm,D = {1.239, 0.903, 0.764, 0.62 µF/cm2}. Parameter values in the parentheses are in the order of increasing distance from 200 to 1000 µm.
