L23 Pain and Suffering

Question 1

1. Which brain region drives quiescence in response to pain of deep or visceral origin?

• medial parabrachial nucleus (mPB)
• lateral periaqueductal gray (lPAG)
• rostral ventrolateral medulla (RVLM)
• ventrolateral periaqueductal gray (vlPAG)

Answer 1

Correct: ventrolatral periaqueductal gray (vlPAG)

The ventrolateral periaqueductal gray evokes a passive emotional coping response, including hypotension, bradycardia, hyporeactivity and quiescence in response to inescapable pain (i.e. deep/visceral pain).

Incorrect:

• mPB evokes a decrease respiratory rate with an increase in BP and HR
• the somato-sympathetic reflex of the RVLM is to increase BP
• the lateral PAG evokes an active emotional coping response, such as fight or flight, in response to cutaneous nociceptive input