A graded potential is produced when a ligand opens a ligand-gated channel in the dendrites, allowing ions to enter (or exit) the cell. For example, Na⁺ will enter the cell and K⁺ will exit, until they both reach equilibrium. The graded potential will degrade with distance, so it would decrement before reaching the end of the axon if an action potential were not generated. The graded potential must be above the threshold value in the spike initiating zone if it is to generate a signal. For each type of neurotransmitter release (eg. ACh), the change in the post-synaptic potential will be proportional to the amount of neurotransmitter release.

Positive charge causes a change in channel protein conformation that leads to opening of the voltage-dependent channels

The signals forming a graded potential can sum or negate one another, increasing or decreasing the possibility of reaching threshold to cause an action potential. There can be temporal summation (over time) or spatial summation (more than one signal).