Motoneuron simulations for counting motor units (Major and Jones 2005)

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Accession:53425
Simulations of clinical methods to count the number of motoneurons/motor units in human patients. Models include stimulation of motor axons or voluntary activation and responses are measured as muscle tension or EMG.
Reference:
1 . Major LA, Jones KE (2005) Simulations of motor unit number estimation techniques. J Neural Eng 2:17-34 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Neuromuscular Junction;
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: MATLAB;
Model Concept(s): Simplified Models; Methods;
Implementer(s): Major, Lora [lora.major at ualberta.ca];
Search NeuronDB for information about:  Spinal cord lumbar motor neuron alpha ACh cell;
function [tw] = twitch_memory(isi,rtime,force,tc)
%% [tw] = twitch_memory(isi,rtime,force,tc)
%% generates muscle twitch using a for loop rather than vectorally
%% saves RAM compared to twitch.m
%% inputs are:
%%   isi = times of spikes
%%   rtime = time sequence for sim
%%   force = peak force for this mu
%%   tc = time constant for this mu
%% output is tw = twitch force over the sim time

tw = zeros(size(rtime));

%% determine time of each spike
stime = isi(isi<rtime(end));

if(length(stime)>0)
    
    for i = 1:length(stime)
        offs = rtime-stime(i);
        offs(offs<0)=0;

    %% twitch function for each spike
        tw = tw + ( force*offs.*exp(1-(offs/tc)) )/tc ;
    
    end
    
end
    
tw = tw(:);

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