Dr. David Anderson

So it could turn out that there is a topographic arrangement along the dorsal ventral axis of the PAG and the medial lateral axis of the PAG

that determines the type of behavior that will be emitted when neurons in that region are stimulated.

And I think sort of all of the evidence is pointing in that direction, but by no means has it been mapped out.

Now, the thing that you mentioned about it not hurting when you got beat up during martial arts, there is a well-known phenomenon called fear induced analgesia.

where when an animal is in a high state of fear, like if it's trying to defend itself, there is a suppression of pain responses.

And I'm not sure completely about the mechanisms and how well that's understood,

But for example, the adrenal gland has a peptide in it that is released from the adrenal medulla, which controls the fight or flight responses.

And that peptide has analgesic activities.

It's called bovine adrenal medullary peptide of 22 amino acid residues.

And I only know about it because it activates a receptor that we discovered many years ago that's involved in pain.

And we thought it promoted pain, but it turns out that this actually inhibits pain.

It's like an endogenous analgesic.

Whether this is happening, this type of analgesia is happening when an animal is engaged in offensive aggression,

or in mating behavior, I don't know, but it certainly is possible.

And I don't know whether these analgesic mechanisms are happening in the pag.

They could also be happening a little further down in the spinal cord.

The pag is really continuous with the spinal cord.

If you just follow it down towards the tail of an animal, you will wind up in the spinal cord.

And so it could be that there are influences acting at many levels on pain in the PAG and in the spinal cord as well.

And it may well be known.