If a postsynaptic cell is at a resting membrane potential of -65mV, what is the result of a stimulus that hyperpolarizes it to -80mV?

If a postsynaptic cell is at a resting membrane potential of -65mV, what is the result of a stimulus that hyperpolarizes it to -80mV?

• A. An action potential will be generated immediately.
• B. The cell will not generate an action potential.
• C. The cell will return to resting potential after a brief excitatory period.
• D. The stimulus enhances the ability to fire future action potentials.

Answer: (B)

When a postsynaptic cell experiences hyperpolarization, as in the scenario where it becomes more negative than its resting membrane potential (moving from -65 mV to -80 mV), it becomes less likely to reach the threshold needed to generate an action potential. Hyperpolarization represents an increase in the negativity of the membrane potential, making it further away from the threshold potential (typically around -55 mV for many neurons) that is required to initiate an action potential. As a result of this hyperpolarization, the cell's excitability decreases because more depolarizing (excitatory) input would be required to bring the membrane potential back to the threshold for an action potential. In essence, the physiological state of the neuron has shifted to make it more difficult for the neuron to respond to subsequent stimuli. This explaining why the outcome of hyperpolarization leads to the conclusion that the cell will not generate an action potential. The hyperpolarized state inhibits the neuron's ability to fire, directly countering the conditions needed for action potential generation.

When a postsynaptic cell experiences hyperpolarization, as in the scenario where it becomes more negative than its resting membrane potential (moving from -65 mV to -80 mV), it becomes less likely to reach the threshold needed to generate an action potential. Hyperpolarization represents an increase in the negativity of the membrane potential, making it further away from the threshold potential (typically around -55 mV for many neurons) that is required to initiate an action potential.

As a result of this hyperpolarization, the cell's excitability decreases because more depolarizing (excitatory) input would be required to bring the membrane potential back to the threshold for an action potential. In essence, the physiological state of the neuron has shifted to make it more difficult for the neuron to respond to subsequent stimuli.

This explaining why the outcome of hyperpolarization leads to the conclusion that the cell will not generate an action potential. The hyperpolarized state inhibits the neuron's ability to fire, directly countering the conditions needed for action potential generation.