By Electrophysiology because neurons generate and transmit electrical signals via ions.
Neurons are polarized cells (resting membrane potential). The difference in voltage across the cell membrane when a neuron or muscle cells is not producing an AP.
A typical value is: -70mV (-50 to -90).
A cell that exhibits a membrane potential is said to be polarized.
Why is the inside of the cell more negative? Because of thefollowing:
The resting membrane is 10-100 times more permeable to K+ than to Na+.
K+ tends to leak out of the cell down its concentration gradient, carrying positive charge with it, and unable to carry Cl- with it because Cl- has higher concentration outside.
The non-diffusible anion (protein, sulphate and phosphate ions) cannot leave the cell.
The Action Potential is a very fast and transient change in the polarity of the neuronal membrane that breaks the ionic equilibrium.
Synaptic transmission is the mode of communication between neurons.