This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Unknown
Stimulation of which brain area can modulate the sensation of pain? 
Select and explain. 
A. Superior olivary complex, B. Locus ceruleus, C. Periaquaductal gray, D. Amygdala
C: Periaquaductal gray
Answer: C: Periaquaductal gray 
Explanation: Endogenous analgesic system
 
periaqueductal gray (PAG)-projects to nucleus raphé magnus and rostral ventromedial medulla
 
project to the dorsal horn of the spinal cord- release serotonin and norepinephrine
 
Locus coerulus-Nor epinephrine
 
Stress induced analgesia:
 
release of endogenous cannabinoids such as 2-arachidonoylglycerol (2AG) and anandamide acts on CB1(Euphoria) and CB 2 (Pain)receptors