TY - JOUR
T1 - Analysis of the interaction between the dendritic conductance density and activated area in modulating α-motoneuron EPSP
T2 - Statistical computer model
AU - Gradwohl, Gideon
AU - Grossman, Yoram
PY - 2008/6/1
Y1 - 2008/6/1
N2 - Five reconstructed α-motoneurons (MNs) are simulated under physiological and morphological realistic parameters. We compare the resulting excitatory postsynaptic potential (EPSP) of models, containing voltage-dependent channels on the dendrites, with the EPSP of a passive MN and an active soma and axon model. In our simulations, we apply three different distribution functions of the voltage-dependent channels on the dendrites: a step function (ST) with uniform spatial dispersion; an exponential decay (ED) function, with proximal to the soma high-density location; and an exponential rise (ER) with distally located conductance density. In all cases, the synaptic inputs are located as a gaussian function on the dendrites. Our simulations lead to eight key observations. (1) The presence of the voltage-dependent channels conductance (gActive) in the dendrites is vital for obtaining EPSP peak boosting. (2) The mean EPSP peaks of the ST, ER, and ED distributions are similar when the ranges of G (total conductance) are equal. (3) EPSP peak increases monotonically when the magnitude of gNa_step (maximal gNa at a particular run) is increased. (4) EPSP kinetics parameters were differentially affected; time integral was decreased monotonically with increased gNa_step, but the rate of rise (the decay time was not analyzed) does not show clear relations. (5) The total G can be elevated by increasing the number of active dendrites; however, only a small active area of the dendritic tree is sufficient to get themaximal boosting. (6) The sometimes large variations in the parameters values for identical G depend on the g Na_step and active dendritic area. (7) High gNa_step in a few dendrites is more efficient in amplifying the EPSP peak than low g Na_step in many dendrites. (8) The EPSP peak is approximately linear with respect to the MNs' RN (input resistance).
AB - Five reconstructed α-motoneurons (MNs) are simulated under physiological and morphological realistic parameters. We compare the resulting excitatory postsynaptic potential (EPSP) of models, containing voltage-dependent channels on the dendrites, with the EPSP of a passive MN and an active soma and axon model. In our simulations, we apply three different distribution functions of the voltage-dependent channels on the dendrites: a step function (ST) with uniform spatial dispersion; an exponential decay (ED) function, with proximal to the soma high-density location; and an exponential rise (ER) with distally located conductance density. In all cases, the synaptic inputs are located as a gaussian function on the dendrites. Our simulations lead to eight key observations. (1) The presence of the voltage-dependent channels conductance (gActive) in the dendrites is vital for obtaining EPSP peak boosting. (2) The mean EPSP peaks of the ST, ER, and ED distributions are similar when the ranges of G (total conductance) are equal. (3) EPSP peak increases monotonically when the magnitude of gNa_step (maximal gNa at a particular run) is increased. (4) EPSP kinetics parameters were differentially affected; time integral was decreased monotonically with increased gNa_step, but the rate of rise (the decay time was not analyzed) does not show clear relations. (5) The total G can be elevated by increasing the number of active dendrites; however, only a small active area of the dendritic tree is sufficient to get themaximal boosting. (6) The sometimes large variations in the parameters values for identical G depend on the g Na_step and active dendritic area. (7) High gNa_step in a few dendrites is more efficient in amplifying the EPSP peak than low g Na_step in many dendrites. (8) The EPSP peak is approximately linear with respect to the MNs' RN (input resistance).
UR - http://www.scopus.com/inward/record.url?scp=45749138310&partnerID=8YFLogxK
U2 - 10.1162/neco.2008.03-07-490
DO - 10.1162/neco.2008.03-07-490
M3 - Article
C2 - 18254701
AN - SCOPUS:45749138310
SN - 0899-7667
VL - 20
SP - 1385
EP - 1410
JO - Neural Computation
JF - Neural Computation
IS - 6
ER -