The stretch reflex and the gamma loop

I created this model in 2003 for the educational proposes of both myself, being a novice Neuron user, and others interested in neurosciences. 
This model roughly recreates the myotatic (stretch) reflex, the way it self regulates and the way this self-regulation is overwritten by the gamma loop. 
Due to obvious difficulties to simulate mechanical stress over the Neuron platform, I decided to create a compartment to represent the
neuro-muscular tangle (the muscle spindle) and electrically stimulate it, although I know it is not physiologically correct.

The simulation is divided in three epochs:
000  200ms  The stretch reflex itself, without cortical intervention
200  400ms  Primary motor (M1) cortical area stimulation of the alpha neuron for enhanced strength
400  600ms  Gamma loop neuron is also stimulated, thus enhancing muscle contraction and overriding the inhibition generated via 
the Golgi tendon organ.
The model is quite simplified for better understanding of the involved mechanisms by pupils and young students. 
One can for instance stimulate the muscle spindle briefly and with a relative high potential, thus simulating the neurologists hammer and generating 
the jerk reflex.

Abbreviations:
Motor  represents the motor neurons, both alpha and gamma
Sens  sensitive neuron (Sens4 is a Ia type neuron and Sens5, 6 are Ib type neurons)
FusNM  neuro-muscular tangle (the muscle spindle)
CTG  Golgi tendon organ
IntN  inter-neuron (serves as inhibitor for the motor neuron)
Myo  represents the muscle in which I counted impulses
P  are artificial pacer neurons representing the primary motor cortical area

Instructions:
By pressing the run button in the run control, the user activates a sequence of 3 epochs previously described. 
However you are invited to modify any parameter or stimulate the network differently (like the jerk reflex). 
To be noted that the Myo component firing frequency is rising from an epoch to another, 
indicating more contraction strength (although I know 100Hz means tetany in most muscles).
