Stimulation

A particular use of the term is physiological stimulation, which refers to sensory excitation, the action of various agents or forms of energy (stimuli) on receptors that generate impulses that travel through nerves to the brain (afferents).

There are also sensory receptors in the muscles, joints, digestive tract, and membranes around organs such as the brain, the abdominal cavity, the bladder and the prostate (providing one source of sexual stimulation).

Stimulation to the external or internal senses may evoke involuntary activity or guide intentions in action.

Such emotional or motivating stimulation typically is also experienced subjectively (enters awareness, is in consciousness).

[citation needed] Chiropractor James Wilson has hypothesized that long-term overstimulation can result eventually in a phenomenon called adrenal fatigue, but there is no evidence that such a condition exists.