Motoneuron pool input-output function (Powers & Heckman 2017)

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Accession:239582
"Although motoneurons have often been considered to be fairly linear transducers of synaptic input, recent evidence suggests that strong persistent inward currents (PICs) in motoneurons allow neuromodulatory and inhibitory synaptic inputs to induce large nonlinearities in the relation between the level of excitatory input and motor output. To try to estimate the possible extent of this nonlinearity, we developed a pool of model motoneurons designed to replicate the characteristics of motoneuron input-output properties measured in medial gastrocnemius motoneurons in the decerebrate cat with voltage- clamp and current-clamp techniques. We drove the model pool with a range of synaptic inputs consisting of various mixtures of excitation, inhibition, and neuromodulation. We then looked at the relation between excitatory drive and total pool output. Our results revealed that the PICs not only enhance gain but also induce a strong nonlinearity in the relation between the average firing rate of the motoneuron pool and the level of excitatory input. The relation between the total simulated force output and input was somewhat more linear because of higher force outputs in later-recruited units. ..."
Reference:
1 . Powers RK, Heckman CJ (2017) Synaptic control of the shape of the motoneuron pool input-output function. J Neurophysiol 117:1171-1184 [PubMed]
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Model Information (Click on a link to find other models with that property)
Model Type: Neuron or other electrically excitable cell;
Brain Region(s)/Organism:
Cell Type(s): Spinal cord lumbar motor neuron alpha ACh cell;
Channel(s):
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s):
Implementer(s): Powers, Randy [rkpowers at u.washington.edu];
Search NeuronDB for information about:  Spinal cord lumbar motor neuron alpha ACh cell;
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RPCH_JNP17
FivecomptcMG
FivecomptcMG_15
FivecomptcMG_15.hoc
                            
//uses dpath of 700 from M1   alternative atten fact for ht (more atten)
soma.diam = 25.93643388249016
soma.L = 3302.8346697769357
soma.g_pas = 0.0002265313908733052
soma.e_pas = -71.49205423531127
soma.gbar_na3rp = 0.01590465082373524
soma.gbar_naps = 2.3047674588132382e-05
soma.sh_na3rp = 1.0
soma.sh_naps = 5.0
soma.ar_na3rp = 1.0
soma.ar_naps = 1.0
soma.gMax_kdrRL = 0.01746027117655635
soma.gcamax_mAHP = 7.657396210733093e-06
soma.gkcamax_mAHP = 0.0005238081352966905
soma.taur_mAHP = 35.3972882344365
soma.ek = -80.0
soma.Ra = 0.001
soma.cm = 1.612838808864266
soma.ghbar_gh = 0.000128410847062254
soma.half_gh = -77.0
forsec dend{
L = 2007.0812319580114
diam = 10.292878865723866
g_pas = 0.00012645647878699518
e_pas = -71.49205423531127
gcabar_L_Ca_inact = 0.00011025368129464937
Ra = 45.97820629829421
cm = 0.8739936767750401
ghbar_gh = 0.000128410847062254
half_gh = -77.0
}
d1.gcabar_L_Ca_inact = 0.0001012377897652719
d2.gcabar_L_Ca_inact = 0.0001112377897652719
d3.gcabar_L_Ca_inact = 0.00011869806094182825
d4.gcabar_L_Ca_inact = 0.00013369806094182826
qinf_na3rp = 8.0
thinf_na3rp = -50.0
vslope_naps = 5.0
asvh_naps = -90.0
bsvh_naps = -22.0
mvhalfca_mAHP = -20.0
mtauca_mAHP = 2.0
celsius = 37.0
theta_m_L_Ca_inact = -38.52383729406619
tau_m_L_Ca_inact = 40.0
theta_h_L_Ca_inact = -22.47368421052632
tau_h_L_Ca_inact = 2500.0
kappa_h_L_Ca_inact = 5.0
htau_gh = 30.0
mVh_kdrRL = -21.0
tmin_kdrRL = 0.8
taumax_kdrRL = 20.0
V0 = -2.6986441172182527