What term describes the level of stimulation needed to trigger a neural impulse?

The term that describes the level of stimulation needed to trigger a neural impulse is known as the threshold. In neuroscience, the threshold refers to the minimum amount of stimulus required to activate a neuron and initiate an action potential. When a neuron responds to sufficient stimulation and this threshold is reached, it results in the rapid depolarization of the neuron's membrane, leading to the generation of an action potential that propagates along the neuron. This concept is fundamental in understanding how neurons communicate and transmit signals, as only when the threshold is surpassed do they respond with a neural impulse.

Other terms mentioned, such as action potential, refer to the result of crossing this threshold; action potentials are the electrical signals that travel along the neuron once this stimulation has occurred. Neurotransmitters are chemicals that transmit signals across synapses between neurons, and the myelin sheath is a protective layer that insulates nerve fibers, enhancing the speed of signal transmission but is not related to the threshold for triggering an impulse. Understanding these distinctions is crucial for grasping the mechanics of neural communication.