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_6
FivecomptcMG_6.hoc
                            
//uses dpath of 700 from M1   alternative atten fact for ht (more atten)
soma.diam = 22.25193176847937
soma.L = 2974.453418865724
soma.g_pas = 9.039824901589152e-05
soma.e_pas = -71.03149147105992
soma.gbar_na3rp = 0.010377897652719055
soma.gbar_naps = 2.581105117364047e-05
soma.sh_na3rp = 1.0
soma.sh_naps = 5.0
soma.ar_na3rp = 1.0
soma.ar_naps = 1.0
soma.gMax_kdrRL = 0.015157457355299607
soma.gcamax_mAHP = 6.412875737197906e-06
soma.gkcamax_mAHP = 0.0004547237206589882
soma.taur_mAHP = 58.425426447003936
soma.ek = -80.0
soma.Ra = 0.001
soma.cm = 1.3719322437673132
soma.ghbar_gh = 3.6298294211984254e-05
soma.half_gh = -77.0
forsec dend{
L = 1807.758878845313
diam = 8.830688807406327
g_pas = 8.23596666423677e-05
e_pas = -71.03149147105992
gcabar_L_Ca_inact = 9.597623560285757e-05
Ra = 50.71417320309082
cm = 0.8681786113136026
ghbar_gh = 3.6298294211984254e-05
half_gh = -77.0
}
d1.gcabar_L_Ca_inact = 8.603921854497741e-05
d2.gcabar_L_Ca_inact = 9.603921854497741e-05
d3.gcabar_L_Ca_inact = 0.00010119667590027702
d4.gcabar_L_Ca_inact = 0.00011619667590027701
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 = -39.90552558682024
tau_m_L_Ca_inact = 40.0
theta_h_L_Ca_inact = -4.189473684210526
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 = -14.212713223501968