I want to complete the laboratory experiments of "NERVE" from the University of Chicagi and I am having several misunderstandings I will be glad to receive help with:
1. As far as I understand, when we consider a single axon (as the one this lab focuses on), every action potential should look exactly the same, and have same amplitude. In particular, action potentials are not "graded", and different stimulus should affect the frequency of the action potential, and not their amplitude. If so, how is it possible that in our case (see attached picture) we have a decrease in the action potential amplitude when we decrease the stimulus intensity? (see red line in the attached picture)
2. In addition, will someone please help me understand why does the progressive reduction of the stimulus intensity cause the onset of the action potential to occur at progressively longer times after the cessation of the stimulus ? (i.e.- we have an increase in the latent period)
Any help in one of the questions I asked will be gratefully acknowledged !
Thanks a lot in advance