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_11
FivecomptcMG_11.hoc
                            
//uses dpath of 700 from M1   alternative atten fact for ht (more atten)
soma.diam = 23.552412888176118
soma.L = 3090.3587986586967
soma.g_pas = 0.00013844777518588717
soma.e_pas = -71.19405161102202
soma.gbar_na3rp = 0.012328619332264179
soma.gbar_naps = 2.483569033386791e-05
soma.sh_na3rp = 1.0
soma.sh_naps = 5.0
soma.ar_na3rp = 1.0
soma.ar_naps = 1.0
soma.gMax_kdrRL = 0.015970258055110074
soma.gcamax_mAHP = 6.666673141905877e-06
soma.gkcamax_mAHP = 0.00047910774165330224
soma.taur_mAHP = 50.297419448899255
soma.ek = -80.0
soma.Ra = 0.001
soma.cm = 1.4569625761772855
soma.ghbar_gh = 6.881032220440298e-05
soma.half_gh = -77.0
forsec dend{
L = 1878.1116562181078
diam = 9.346783114156583
g_pas = 9.792406852310832e-05
e_pas = -71.19405161102202
gcabar_L_Ca_inact = 0.00010101559994168247
Ra = 49.04256728386062
cm = 0.870231095640764
ghbar_gh = 6.881032220440298e-05
half_gh = -77.0
}
d1.gcabar_L_Ca_inact = 9.14037031637265e-05
d2.gcabar_L_Ca_inact = 0.0001014037031637265
d3.gcabar_L_Ca_inact = 0.00010737396121883657
d4.gcabar_L_Ca_inact = 0.00012237396121883657
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 = -39.41784516693396
tau_m_L_Ca_inact = 40.0
theta_h_L_Ca_inact = -14.347368421052632
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 = -10.148709724449628