My professor says , at a more negative RMP, less sodium ion channels are inactivated, so if you take 2 of the exact same neuron with the same threshold potentials, and try to excite them starting from different membrane potentials, the one you try to excite from a more negative membrane potential excites faster and fires an action potential faster because more sodium ion channels are activated .
I might have missed something from what he said, and I hope I did because this makes no sense to me. Shouldn't excitability increase with an increasing positive resting membrane potential ? The closer I am to the threshold potential the weaker the stimulus that I need to fire an action potential, isn't that right ?
The only article I found on this is https://www.sciencedirect.com/topics/neuroscience/excitability and its specific to cardiac muscle so perhaps the excitability in cardiac muscle is an exception ?