If an inhibitory synapse fires at the same time and at the same distance from the initial segment as an excitatory synapse of the same intensity, what will be the effect on the membrane potential at the trigger zone? 1) an action potential will be generated 2) a sub threshold depolarization 3) no change 4) a subthreshold hyperpolarization

If an inhibitory synapse fires at the same time and at the same distance from the initial segment as an excitatory synapse of the same intensity there will be no changes in the potential in the firing zone.

Explanation:

An excitatory synapse is one capable of depolarizing a cell and boosting the production of action potential, provided it is capable of reaching the threshold of said potential.

On the other hand, an inhibitory synapse is able to hyperpolarize the cell membrane and prevent an action potential from originating, so that they can inhibit the action of an excitatory synapse.

The interaction between two synapses, one excitatory and one inhibitory, -called synapse summation- will depend on the strength that each of them possesses. In this case, the intensity of both synapses being the same, there will be no changes in the membrane potential in the firing zone.

Learn more:

Excitatory and inhibitory postsynaptic potentials link