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_18
FivecomptcMG_18.hoc
                            
//uses dpath of 700 from M1   alternative atten fact for ht (more atten)
soma.diam = 28.802157748942992
soma.L = 3558.242309374544
soma.g_pas = 0.00033241272342907123
soma.e_pas = -71.85026971861788
soma.gbar_na3rp = 0.02020323662341449
soma.gbar_naps = 2.0898381688292757e-05
soma.sh_na3rp = 1.0
soma.sh_naps = 5.0
soma.ar_na3rp = 1.0
soma.ar_naps = 1.0
soma.gMax_kdrRL = 0.01925134859308937
soma.gcamax_mAHP = 9.528804139091369e-06
soma.gkcamax_mAHP = 0.000577540457792681
soma.taur_mAHP = 17.486514069106292
soma.ek = -80.0
soma.Ra = 0.001
soma.cm = 1.8002105817174514
soma.ghbar_gh = 0.00020005394372357482
soma.half_gh = -77.0
forsec dend{
L = 2162.109728823443
diam = 11.43013779997084
g_pas = 0.00016075399934392768
e_pas = -71.85026971861788
gcabar_L_Ca_inact = 0.00012135836127715409
Ra = 42.294676483452406
cm = 0.8785165054672693
ghbar_gh = 0.00020005394372357482
half_gh = -77.0
}
d1.gcabar_L_Ca_inact = 0.00011305890071438985
d2.gcabar_L_Ca_inact = 0.00012305890071438985
d3.gcabar_L_Ca_inact = 0.00013231024930747921
d4.gcabar_L_Ca_inact = 0.00014731024930747923
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 = -37.44919084414638
tau_m_L_Ca_inact = 40.0
theta_h_L_Ca_inact = -28.568421052631578
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 = 6.256742965446854