Discharge hysteresis in motoneurons (Powers & Heckman 2015)

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Accession:183949
"Motoneuron activity is strongly influenced by the activation of persistent inward currents (PICs) mediated by voltage-gated sodium and calcium channels. ... It has recently been suggested that a number of factors other than PIC can contribute to delta F (firing rate differences between motoneurons) values, including mechanisms underlying spike frequency adaptation and spike threshold accommodation. In the present study, we used a set of compartmental models representing a sample of 20 motoneurons with a range of thresholds to investigate how several different intrinsic motoneuron properties can potentially contribute to variations in F values. ... Our results indicate that, although other factors can contribute, variations in discharge hysteresis and delta F values primarily reflect the contribution of dendritic PICs to motoneuron activation.
Reference:
1 . Powers RK, Heckman CJ (2015) Contribution of intrinsic motoneuron properties to discharge hysteresis and its estimation based on paired motor unit recordings. A simulation study. J Neurophysiol 114:184-198 [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 cell;
Channel(s): I Na,p; I Na,t; I L high threshold; I K; I M; I K,Ca; I_AHP; I Calcium; I Sodium;
Gap Junctions:
Receptor(s):
Gene(s): Kv1.2 KCNA2; Kv1.9 Kv7.1 KCNQ1;
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Spike Frequency Adaptation;
Implementer(s): Powers, Randy [rkpowers at u.washington.edu];
Search NeuronDB for information about:  Spinal cord lumbar motor neuron alpha cell; I Na,p; I Na,t; I L high threshold; I K; I M; I K,Ca; I Sodium; I Calcium; I_AHP;
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Discharge_hysteresis
Model hoc files and output
README.txt
Gfluctdv.mod *
ghchan.mod *
kca2.mod *
KCNQ.mod *
kdrRL.mod *
km_hu.mod
kv1_gp.mod *
L_Ca.mod *
L_Ca_inact.mod *
mAHP.mod *
mAHPvt.mod
na3rp.mod *
naps.mod *
napsi.mod *
AHPlen.csv
FasterMis.csv
FR3cablepas.hoc
FRMot3dendNaHH.hoc
gramp.ses
HiDKCa.csv
init_3dend_gramp.hoc
LCai.csv
Napi.csv
pars2manyhocs.py *
ProxCa.csv
SetConductances2.hoc *
SlowM.csv
standard.csv
twobirampsdel.hoc *
                            
// FRMotoneuron.hoc
// Base code to create motoneuron and CC & VC ramp
// Expected to be executed from some other directory, with THIS file location and its 
// helpers in the directory "codeloc"

{xopen("FR3cablepas.hoc")}

access soma
insert na3rp
insert naps
insert kdrRL
gMax_kdrRL=0.1
insert mAHP
gkcamax_mAHP=0.01
gcamax_mAHP=1.5e-5
eca=80
insert gh

access axonhillock
insert na3rp
insert naps
insert kdrRL
gMax_kdrRL=0.15

access is
insert na3rp
insert naps
insert kdrRL
gMax_kdrRL=0.6

forsec dend{
insert gh
insert na3rp
insert naps
insert kdrRL
insert kca2
insert L_Ca
insert mAHP
gcamax_mAHP(0:0.1)=1.5e-5:1.5e-5
gcamax_mAHP(0.1:1)=0:0
gkcamax_mAHP(0:0.1)=0.004:0.004
gkcamax_mAHP(0.1:1)=0:0
gMax_kdrRL(0:1)=0.07:0
g_kca2(0:0.3)=0:0
g_kca2(0.3:0.6)=3.8e-4:3.8e-4
g_kca2(0.6:1)=0:0
gcabar_L_Ca (0:0.3)=0:0
gcabar_L_Ca(0.3:0.6)=4e-4:4e-4
gcabar_L_Ca (0.6:1)=0:0
depth2_kca2=1000
taur2_kca2=425
depth1_kca2=0.1
taur1_kca2=20
eca=80
}

access soma

theta_m_L_Ca=-40
tau_m_L_Ca=60


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