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_4
FivecompthTAlw_4.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 = 22.192509252077564
soma.L = 2969.1573881440445
soma.g_pas = 8.820268698060941e-05
soma.e_pas = -71.0240620498615
soma.gbar_na3rp = 0.010288753462603878
soma.gbar_naps = 2.5855617950138504e-05
soma.sh_na3rp = 1.0
soma.sh_naps = 5.0
soma.ar_na3rp = 1.0
soma.ar_naps = 1.0
soma.gMax_kdrRL = 0.015120318227146814
soma.gcamax_mAHP = 6.402374144090362e-06
soma.gkcamax_mAHP = 0.00045360775623268695
soma.taur_mAHP = 88.55618038781164
soma.ek = -80.0
soma.Ra = 0.001
soma.cm = 1.3680468144044322
soma.ghbar_gh = 3.481272022160665e-05
soma.half_gh = -77.0
forsec dend{
L = 1804.5442701385043
diam = 8.807107119113574
g_pas = 8.164847783933517e-05
e_pas = -71.0240620498615
gcabar_L_Ca_inact = 9.574592797783935e-05
Ra = 50.79055339612188
cm = 0.8680848227146815
ghbar_gh = 3.481272022160665e-05
half_gh = -77.0
}
d1.gcabar_L_Ca_inact = 8.579423822714682e-05
d2.gcabar_L_Ca_inact = 9.579423822714682e-05
d3.gcabar_L_Ca_inact = 0.00010091434903047092
d4.gcabar_L_Ca_inact = 0.00011591434903047092
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 = -41.927808975069254
tau_m_L_Ca_inact = 40.0
theta_h_L_Ca_inact = 9.518727977839335
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 = -14.214227146814405

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