Thefourth step in sensing pain the message has finally made it to the brain.
We feel annoyed or irritated at beingpricked. Once to the brain, the messageis passed to the thalamus. The thalamussorts acts as a sorting station that relays the messages to the different partsof our brains. The messages are sent tothe somatosensory cortex (responsible for physical sensation), frontal cortex(in charge of thinking) and limbic system (link to emotion). In the periaqueductal gray matter in thebrain, which determines our perception of pain, acts as a relay for axons thatcarry the pain messages from the dorsal horn to the cortex.
This area is full of receptors for opiatedrugs like morphine and their counter parts. Our bodies naturally produces the endogenous opioids into the bloodstream that reduce pain throughout the body. In our field we will have to determine who needs opioids for true painverses addiction. The challenge is thatthe perception of pain varies from one individual to another.