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]
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
FivecompthTAlw
FivecompthTAlw_9
FivecompthTAlw_9.hoc
                            
//uses dpath of 700 from M1   alternative atten fact for ht (more atten)
//modified from hTA to make parameters for last MN same as previous MN_14
soma.diam = 22.97457808864266
soma.L = 3038.859277479224
soma.g_pas = 0.00011709797783933517
soma.e_pas = -71.12181412742382
soma.gbar_na3rp = 0.011461814404432133
soma.gbar_naps = 2.5269065872576177e-05
soma.sh_na3rp = 1.0
soma.sh_naps = 5.0
soma.ar_na3rp = 1.0
soma.ar_naps = 1.0
soma.gMax_kdrRL = 0.015609111024930747
soma.gcamax_mAHP = 6.460846716315866e-06
soma.gkcamax_mAHP = 0.00046826426592797785
soma.taur_mAHP = 82.6906632132964
soma.ek = -80.0
soma.Ra = 0.001
soma.cm = 1.4191807479224379
soma.ghbar_gh = 5.436439612188365e-05
soma.half_gh = -77.0
forsec dend{
L = 1846.8522425761773
diam = 9.117470415512466
g_pas = 9.100838781163435e-05
e_pas = -71.12181412742382
gcabar_L_Ca_inact = 9.877626038781165e-05
Ra = 49.78530156786703
cm = 0.8693191024930748
ghbar_gh = 5.436439612188365e-05
half_gh = -77.0
}
d1.gcabar_L_Ca_inact = 8.902083102493075e-05
d2.gcabar_L_Ca_inact = 9.902083102493075e-05
d3.gcabar_L_Ca_inact = 0.000104628891966759
d4.gcabar_L_Ca_inact = 0.000119628891966759
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 = -41.63453293628809
tau_m_L_Ca_inact = 40.0
theta_h_L_Ca_inact = 7.563560387811634
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 = -11.022024930747923

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