Why do neurons need a steady supply of atp?

Neurons are constantly carrying action potentials (meaning electrical signals) in order to result in a certain action carried out by the body. Therefore, Neurons need a high amount of ATP to carry an action potential throughout the nervous system to be processed by the brain and then initiate a motor (physical response)

For example if you touch a hot stove, sensory neurons will take the "hot" information from the hand to the spinal cord which has relay neurons which connect the action potential (which is the information) to the brain. The brain in response will interpret that information and initiate a motor response. Which will result in you taking your hand off the stove. This entire process of responding to stimuli takes a lot of energy to take place. Just the brain itself takes about 20% of all daily basal energy (which is the energy required to keep you alive).