Nociception is the bodies response to certain painful or harmful stimulus. The word is derived from the Latin "nocere" meaning "to harm or hurt". Nerve endings called nociceptors detect stimuli and trigger a variety physiological response.
In psychology, the Stroop effect is a demonstration of cognitive interference where a delay in the reaction time of a task occurs due to a mismatch in stimuli. The Stroop Task is one of the best known psychological experiments named after John Ridley Stroop. The Stroop phenomenon demonstrates that it is difficult to name the color of a color word if there is a mismatch between color and word e.g. green
Norepinephrine, also called noradrenaline or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as a hormone and neurotransmitter. A naturally occuring chemical that acts as both a stress hormone and a neurotransmitter.