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_8
FivecomptcMG_8.hoc
                            
//uses dpath of 700 from M1   alternative atten fact for ht (more atten)
soma.diam = 22.597171599358507
soma.L = 3005.222918792827
soma.g_pas = 0.00010315399766729843
soma.e_pas = -71.07464644991981
soma.gbar_na3rp = 0.01089575739903776
soma.gbar_naps = 2.555212130048112e-05
soma.sh_na3rp = 1.0
soma.sh_naps = 5.0
soma.ar_na3rp = 1.0
soma.ar_naps = 1.0
soma.gMax_kdrRL = 0.015373232249599066
soma.gcamax_mAHP = 6.454258250578834e-06
soma.gkcamax_mAHP = 0.000461196967487972
soma.taur_mAHP = 56.267677504009335
soma.ek = -80.0
soma.Ra = 0.001
soma.cm = 1.3945053185595568
soma.ghbar_gh = 4.4929289983962674e-05
soma.half_gh = -77.0
forsec dend{
L = 1826.4354905962969
diam = 8.967696802740925
g_pas = 8.649156167079749e-05
e_pas = -71.07464644991981
gcabar_L_Ca_inact = 9.731403994751422e-05
Ra = 50.270410555474555
cm = 0.8687234860766876
ghbar_gh = 4.4929289983962674e-05
half_gh = -77.0
}
d1.gcabar_L_Ca_inact = 8.746333284735384e-05
d2.gcabar_L_Ca_inact = 9.746333284735384e-05
d3.gcabar_L_Ca_inact = 0.00010283656509695292
d4.gcabar_L_Ca_inact = 0.00011783656509695292
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 = -39.77606065024056
tau_m_L_Ca_inact = 40.0
theta_h_L_Ca_inact = -8.25263157894737
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 = -13.133838752004666