Final answer:
The term that refers to how long a stimulus lasts is 'duration.' It is one of the four aspects encoded by sensory systems, alongside intensity, modality, and location, and relates specifically to the time span of the stimulus effect.
Step-by-step explanation:
The term that refers to how long a stimulus lasts is duration. The duration of a stimulus is one of the four aspects of sensory information encoded by sensory systems. A stimulus of longer duration will cause a more extended depolarization in neural pathways, however, the strength remains the same as a shorter lasting stimulus. This is distinct from the intensity of a stimulus, which is encoded by both the rate of action potentials and the number of receptors activated by the stimulus. The modality of a stimulus, meanwhile, refers to a specific type of stimulus, such as light or sound, that a particular sensory system can recognize and interpret.