A model of the femur-tibia control system in stick insects (Stein et al. 2008)

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Accession:118092
We studied the femur-tibia joint control system of the insect leg, and its switch between resistance reflex in posture control and "active reaction" in walking. The "active reaction" is basically a reversal of the resistance reflex. Both responses are elicited by the same sensory input and the same neuronal network (the femur-tibia network). The femur-tibia network was modeled by fitting the responses of model neurons to those obtained in animals. Each implemented neuron has a physiological counterpart. The strengths of 16 interneuronal pathways that integrate sensory input were then assigned three different values and varied independently, generating a database of more than 43 million network variants. The uploaded version contains the model that best represented the resistance reflex. Please see the README for more help. We demonstrate that the combinatorial code of interneuronal pathways determines motor output. A switch between different behaviors such as standing to walking can thus be achieved by altering the strengths of selected sensory integration pathways.
Reference:
1 . Stein W, Straub O, Ausborn J, Mader W, Wolf H (2008) Motor pattern selection by combinatorial code of interneuronal pathways. J Comput Neurosci 25:543-61 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Realistic Network; Neuron or other electrically excitable cell; Synapse;
Brain Region(s)/Organism:
Cell Type(s): Stick insect nonspiking interneuron;
Channel(s):
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: MadSim;
Model Concept(s): Detailed Neuronal Models; Invertebrate; Synaptic Integration;
Implementer(s): Mader, Wolfgang [wolfgang.mader at uni-ulm.de];
This it the readme for the MadSim model associated with the paper:

Stein W, Straub O, Ausborn J, Mader W, Wolf H. (2008)
Motor pattern selection by combinatorial code of interneuronal pathways.
J Comput Neurosci 25:543-61 

Abstract/Info: We studied the femur-tibia joint control system of the
insect leg, and its switch between resistance reflex in posture
control and "active reaction" in walking. The "active reaction" is
basically a reversal of the resistance reflex. Both responses are
elicited by the same sensory input and the same neuronal network (the
femur-tibia network).  The femur-tibia network was modeled by fitting
the responses of model neurons to those obtained in animals. Each
implemented neuron has a physiological counterpart. The strengths of
16 interneuronal pathways that integrate sensory input were then
assigned three different values and varied independently, generating a
database of more than 43 million network variants. The uploaded
version contains the model that best represented the resistance
reflex. Please see below for more help.  We demonstrate that the
combinatorial code of interneuronal pathways determines motor
output. A switch between different behaviors such as standing to
walking can thus be achieved by altering the strengths of selected
sensory integration pathways.


Short info on using madSim Simulator:

Copy the whole madsim folder to your hard disk. No installation
needed. Madsim files are called .gui files. They are ASCII text files
containing all parameters of the simulation. Click file -> open to open
.gui files or use right mouse click to make new neuron / edit
properties etc. To display result window in madSim, either select
neurons with mouse and press CTRL + M or right click on neuron and
select "display diagram window". Then press F1 to start simulation.
Please note that madSim was originally developed in German. The
English version has the same capablilities, but may come with
translation errors.  Btw: MadSim uses HH equations and exponential
Euler to calculate ion / synaptic currents.


Information about the code:

Neurons in "stick_insect_FT-simulation_resistance-reflex.gui":

Sensory neurons in the femoral chordotonal organ:

1, 10, 11 = position (+) sensitive 
30,31,32 = position (-) sensitive
2,3,5,26,27 = velocity (+) sensitive
8,9,12,28,29 = velocity (+) sensitive

20,21,22 = velocity (+) sensitive spiking interneurons 
23,24,25 = velocity (-) sensitive spiking interneurons 

E1 – E10 = identified excitatory nonspiking interneurons
I1 – I8 = identified inhibitory nonspiking interneurons
IE1 = identified interneuron that inhibits and excites

SETi = Slow extensor tibiae motor neuron

The model files were supplied by Wolfgang Stein.

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