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_13
FivecomptcMG_13.hoc
                            
//uses dpath of 700 from M1   alternative atten fact for ht (more atten)
soma.diam = 24.562472663653594
soma.L = 3180.3803761481267
soma.g_pas = 0.00017576695874034118
soma.e_pas = -71.3203090829567
soma.gbar_na3rp = 0.01384370899548039
soma.gbar_naps = 2.4078145502259803e-05
soma.sh_na3rp = 1.0
soma.sh_naps = 5.0
soma.ar_na3rp = 1.0
soma.ar_naps = 1.0
soma.gMax_kdrRL = 0.016601545414783495
soma.gcamax_mAHP = 7.014798237065642e-06
soma.gkcamax_mAHP = 0.0004980463624435048
soma.taur_mAHP = 43.98454585216504
soma.ek = -80.0
soma.Ra = 0.001
soma.cm = 1.5230040720221607
soma.ghbar_gh = 9.406181659133986e-05
soma.half_gh = -77.0
forsec dend{
L = 1932.7533649220004
diam = 9.7476240734801
g_pas = 0.00011001265330223065
e_pas = -71.3203090829567
gcabar_L_Ca_inact = 0.00010492958157165768
Ra = 47.74426169995626
cm = 0.8718252224814114
ghbar_gh = 9.406181659133986e-05
half_gh = -77.0
}
d1.gcabar_L_Ca_inact = 9.557019973757108e-05
d2.gcabar_L_Ca_inact = 0.00010557019973757108
d3.gcabar_L_Ca_inact = 0.00011217174515235457
d4.gcabar_L_Ca_inact = 0.00012717174515235457
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 = -39.0390727511299
tau_m_L_Ca_inact = 40.0
theta_h_L_Ca_inact = -18.410526315789475
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 = -6.992272926082519