Final answer:
Referred pain is when the brain misinterprets pain from a visceral organ due to converging visceral afferent information with somatosensory neurons, resulting in the sensation of pain in somatic structures like the shoulder or arm.
Step-by-step explanation:
In one instance of referred pain, visceral afferent information converges on a secondary neuron of the Anterolateral System (ALS) and activates it, sending a signal to the cortex which is interpreted as pain coming from a somatic structure. This phenomenon occurs because visceral sensory fibers enter into the same level of the spinal cord as the somatosensory fibers of the referred pain location, causing the brain to misinterpret the visceral sensations as originating from a different body area such as the shoulder or arm. Typically, these sensations are connected with a problem in a visceral organ, like the heart, but are perceived in regions where the somatosensory nerves are located.