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_17
FivecomptcMG_17.hoc
                            
//uses dpath of 700 from M1   alternative atten fact for ht (more atten)
soma.diam = 27.730281382125675
soma.L = 3462.7113281819506
soma.g_pas = 0.0002928095713660884
soma.e_pas = -71.71628517276571
soma.gbar_na3rp = 0.01859542207318851
soma.gbar_naps = 2.1702288963405744e-05
soma.sh_na3rp = 1.0
soma.sh_naps = 5.0
soma.ar_na3rp = 1.0
soma.ar_naps = 1.0
soma.gMax_kdrRL = 0.018581425863828546
soma.gcamax_mAHP = 8.751042385623514e-06
soma.gkcamax_mAHP = 0.0005574427759148564
soma.taur_mAHP = 24.185741361714534
soma.ek = -80.0
soma.Ra = 0.001
soma.cm = 1.7301272853185596
soma.ghbar_gh = 0.00017325703455314188
soma.half_gh = -77.0
forsec dend{
L = 2104.1238970695435
diam = 11.004765003644847
g_pas = 0.00014792558200903925
e_pas = -71.71628517276571
gcabar_L_Ca_inact = 0.000117204840355737
Ra = 43.672439568450216
cm = 0.8768248165913399
ghbar_gh = 0.00017325703455314188
half_gh = -77.0
}
d1.gcabar_L_Ca_inact = 0.0001086374107012684
d2.gcabar_L_Ca_inact = 0.0001186374107012684
d3.gcabar_L_Ca_inact = 0.00012721883656509694
d4.gcabar_L_Ca_inact = 0.00014221883656509695
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 = -37.851144481702875
tau_m_L_Ca_inact = 40.0
theta_h_L_Ca_inact = -26.536842105263162
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 = 2.907129319142733