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_14
FivecomptcMG_14.hoc
                            
//uses dpath of 700 from M1   alternative atten fact for ht (more atten)
soma.diam = 25.200466540312
soma.L = 3237.2415804053066
soma.g_pas = 0.00019933923749817757
soma.e_pas = -71.400058317539
soma.gbar_na3rp = 0.014800699810467997
soma.gbar_naps = 2.3599650094766002e-05
soma.sh_na3rp = 1.0
soma.sh_naps = 5.0
soma.ar_na3rp = 1.0
soma.ar_naps = 1.0
soma.gMax_kdrRL = 0.017000291587694998
soma.gcamax_mAHP = 7.290545329568809e-06
soma.gkcamax_mAHP = 0.00051000874763085
soma.taur_mAHP = 39.997084123050016
soma.ek = -80.0
soma.Ra = 0.001
soma.cm = 1.5647185041551248
soma.ghbar_gh = 0.00011001166350779996
soma.half_gh = -77.0
forsec dend{
L = 1967.2672386645283
diam = 10.000811145939641
g_pas = 0.0001176482836419303
e_pas = -71.400058317539
gcabar_L_Ca_inact = 0.000107401807843709
Ra = 46.924200320746465
cm = 0.8728321363172474
ghbar_gh = 0.00011001166350779996
half_gh = -77.0
}
d1.gcabar_L_Ca_inact = 9.8201924478787e-05
d2.gcabar_L_Ca_inact = 0.000108201924478787
d3.gcabar_L_Ca_inact = 0.00011520221606648199
d4.gcabar_L_Ca_inact = 0.000130202216066482
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 = -38.799825047383
tau_m_L_Ca_inact = 40.0
theta_h_L_Ca_inact = -20.442105263157895
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 = -4.998542061525006