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_12
FivecomptcMG_12.hoc
                            
//uses dpath of 700 from M1   alternative atten fact for ht (more atten)
soma.diam = 24.015454147834962
soma.L = 3131.627350925791
soma.g_pas = 0.00015555599212713222
soma.e_pas = -71.25193176847937
soma.gbar_na3rp = 0.013023181221752441
soma.gbar_naps = 2.4488409389123777e-05
soma.sh_na3rp = 1.0
soma.sh_naps = 5.0
soma.ar_na3rp = 1.0
soma.ar_naps = 1.0
soma.gMax_kdrRL = 0.01625965884239685
soma.gcamax_mAHP = 6.812023590333019e-06
soma.gkcamax_mAHP = 0.0004877897652719055
soma.taur_mAHP = 47.403411576031495
soma.ek = -80.0
soma.Ra = 0.001
soma.cm = 1.4872379501385042
soma.ghbar_gh = 8.038635369587403e-05
soma.half_gh = -77.0
forsec dend{
L = 1903.161030762502
diam = 9.53054045925062
g_pas = 0.00010346583313894153
e_pas = -71.25193176847937
gcabar_L_Ca_inact = 0.00010280988482286047
Ra = 48.447385624726635
cm = 0.8709618905088206
ghbar_gh = 8.038635369587403e-05
half_gh = -77.0
}
d1.gcabar_L_Ca_inact = 9.331374835981922e-05
d2.gcabar_L_Ca_inact = 0.00010331374835981921
d3.gcabar_L_Ca_inact = 0.00010957340720221607
d4.gcabar_L_Ca_inact = 0.00012457340720221607
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 = -39.24420469456189
tau_m_L_Ca_inact = 40.0
theta_h_L_Ca_inact = -16.378947368421052
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 = -8.701705788015747