I am a physicist interested in knowing how the action potential frequency in a presynaptic neuron compares with that in
a) a post-synaptic neuron and
b) membrane depolarisation of muslce cells, and
c) how the membrane depolarisation of muscle cells quantititavely relates to muscle contraction.
From the reading I have done so far, it seems that the theory of c) is standard, and goes by the name is 'excitation-contraction coupling'. I would think that the actual relationship between the frequency of muscle cell membrane depolarisation and degree of muscle contraction- however it is quantitifed- would differ for muscle type, depletion of Ca2+ stores from the sarcoplasmic reticulum, etc. In any case, some theory is covered here for instance, although I haven't seen much mathematical modelling and quanitative comparison here.
In any case, I am then still wondering regarding a) and b). I would think that there isn't a straightforward answer; the sequence of events is action potential -> neurotransmitter release into synaptic cleft -> neurotransmitter binding -> membrane depolarisation -> hopefully an action potential.
I already see some potential sources of non-linear behaviour in the final step, and the neurotransmitter binding ->depolarisation step would prbably also be dependent on the recptor kinetics. Since we are talking on the behaviour on a temporal scale, we would have to consider the degredation rate of the neurotransmitter within the synaptic cleft, and no doubt several pathologies arise because of some dysfunction in changes in neurotransmitter degredation/re-uptake rate... Come to think of it now actually, I think differences in the extent of binding (say due to differences in the number of receptors on post-synaptic neuron membrane) are the basis- or at least one factor- in neuroplasticity. So of course they would differ. But still the question remains as to what extent. I am not sure whether for some circuits, say those in the motor system, there is little deviation between responses in people.
To give some context to my question, I am interested in technologies which actively stimulate, or disrupt stimulation, of neurons in a controlled manner, so as to achieve a desired output effect. There are several technologies and lab techniques being developed with this in mind- optogenetics on the single-neuron level, DBS and epidural stimulation for stimulating large groups of neurons for some non-specific duration of time. I would think that these techniques could be much more powerful and potent, if we knew the temporal relationship between consecutive neural firing rates on stimulation.