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_16
FivecomptcMG_16.hoc
                            
//uses dpath of 700 from M1   alternative atten fact for ht (more atten)
soma.diam = 26.777372794868057
soma.L = 3377.7833503426154
soma.g_pas = 0.0002576019813383875
soma.e_pas = -71.5971715993585
soma.gbar_na3rp = 0.01716605919230208
soma.gbar_naps = 2.241697040384896e-05
soma.sh_na3rp = 1.0
soma.sh_naps = 5.0
soma.ar_na3rp = 1.0
soma.ar_naps = 1.0
soma.gMax_kdrRL = 0.017985857996792535
soma.gcamax_mAHP = 8.136264018522683e-06
soma.gkcamax_mAHP = 0.000539575739903776
soma.taur_mAHP = 30.141420032074652
soma.ek = -80.0
soma.Ra = 0.001
soma.cm = 1.6678225484764542
soma.ghbar_gh = 0.0001494343198717014
soma.half_gh = -77.0
forsec dend{
L = 2052.5739247703746
diam = 10.626604421927395
g_pas = 0.00013652099336637993
e_pas = -71.5971715993585
gcabar_L_Ca_inact = 0.00011351231958011372
Ra = 44.89728444379647
cm = 0.8753208886135005
ghbar_gh = 0.0001494343198717014
half_gh = -77.0
}
d1.gcabar_L_Ca_inact = 0.00010470666277883073
d2.gcabar_L_Ca_inact = 0.00011470666277883073
d3.gcabar_L_Ca_inact = 0.00012269252077562326
d4.gcabar_L_Ca_inact = 0.00013769252077562328
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 = -38.20848520192448
tau_m_L_Ca_inact = 40.0
theta_h_L_Ca_inact = -24.50526315789474
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 = -0.07071001603732618