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_4
FivecomptcMG_4.hoc
                            
//uses dpath of 700 from M1   alternative atten fact for ht (more atten)
soma.diam = 22.074646449919815
soma.L = 2958.6528648491035
soma.g_pas = 8.38479997084123e-05
soma.e_pas = -71.00933080623997
soma.gbar_na3rp = 0.01011196967487972
soma.gbar_naps = 2.594401516256014e-05
soma.sh_na3rp = 1.0
soma.sh_naps = 5.0
soma.ar_na3rp = 1.0
soma.ar_naps = 1.0
soma.gMax_kdrRL = 0.015046654031199883
soma.gcamax_mAHP = 6.401695570330588e-06
soma.gkcamax_mAHP = 0.0004513996209359965
soma.taur_mAHP = 59.533459688001166
soma.ek = -80.0
soma.Ra = 0.001
soma.cm = 1.3603406648199448
soma.ghbar_gh = 3.186616124799533e-05
soma.half_gh = -77.0
forsec dend{
L = 1798.1681863245371
diam = 8.760333350342616
g_pas = 8.023788270884968e-05
e_pas = -71.00933080623997
gcabar_L_Ca_inact = 9.528925499343928e-05
Ra = 50.94205131943432
cm = 0.867898810759586
ghbar_gh = 3.186616124799533e-05
half_gh = -77.0
}
d1.gcabar_L_Ca_inact = 8.530791660591923e-05
d2.gcabar_L_Ca_inact = 9.530791660591923e-05
d3.gcabar_L_Ca_inact = 0.00010035457063711912
d4.gcabar_L_Ca_inact = 0.00011535457063711912
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 = -39.97200758128007
tau_m_L_Ca_inact = 40.0
theta_h_L_Ca_inact = -0.1263157894736846
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 = -14.766729844000583