I know that many neurons have an input current-spiking frequency (I-F) relationships, [e.g. as seen here.][1]

However, all the I-F curves I've encountered show the input current in a fairly small range (few pA or nA), suggesting that there is no limit to this behavior.

However, if the current is increased indefinitely, there is a point where the membrane voltage does not recover to the resting, or smaller, potential. For example, here are voltage traces of a simulated [mitral cell][2]:

**At 0.1nA**:
 
[![enter image description here][3]][3]

**0.5nA**:
 
[![enter image description here][4]][4]

**1nA**:
 
[![enter image description here][5]][5]

**10nA**:
 
[![enter image description here][6]][6]

How do neurons limit the amount of current that enters the cell? If the cell is large, with many channels, it seems like there would be stimuli that could result in "too many channels" open at the same time. **How do cells ensure the input current remains within the acceptable range?** 

  [1]: https://grey.colorado.edu/mediawiki/sites/CompCogNeuro/images/8/8f/refractory.png
  [2]: https://en.wikipedia.org/wiki/Olfactory_bulb_mitral_cell
  [3]: https://i.sstatic.net/AmdK2.png
  [4]: https://i.sstatic.net/1RK19.png
  [5]: https://i.sstatic.net/CVGpe.png
  [6]: https://i.sstatic.net/Rk3BG.png