When two or more graded potentials arrive at the trigger zone, which of the following could happen?
A) An excitatory and inhibitory signal can cancel each other out.
B) Two excitatory stimuli may be additive, and summation could occur.
C) Two inhibitory stimuli may be additive, resulting in lower excitability.
D) An excitatory and inhibitory signal can cancel each other out and two excitatory stimuli may be additive, and summation could occur.
E) An excitatory and inhibitory signal can cancel each other out; two excitatory stimuli may be additive, and summation could occur; and two inhibitory stimuli may be additive, resulting in lower excitability.

Question

Quizplus · Accepted Answer

Graded potentials can summate, meaning they can add together to become larger in amplitude. When an excitatory and an inhibitory signal meet, they can indeed cancel each other out. If two excitatory signals meet, they can add together (summate) to potentially reach the threshold for an action potential. Similarly, two inhibitory signals can also add together, further hyperpolarizing the neuron and making it less likely to fire an action potential. Therefore, all the described scenarios are possible.

When Two or More Graded Potentials Arrive at the Trigger