Re: Is it true that the human brain can be operated on without anesthetics?

It is true that cortical and subcortical brain tissue, when injured 
during surgery, will react (to clear away debris, swell, etc.) in a way 
that is not communicated to other parts of the brain that monitor pain, 
and that so-called "pain receptors" that react to painful stimuli in the 
skin are not present in brain tissue (see "Molecular mechanisms of 
nociception" by D. Julius and AI Basbaum in the journal Nature vol 413, 
p. 203, September 2001).  However, to access the brain, incisions must be 
made through skin, fascia, bone, and the membranes that cover the brain 
(dura and pia mater, plus the arachnoid).  Vessels and nerves in these 
extra brain structures contain plentiful pain receptors, so that brain 
surgery will often involve considerable postoperative pain, including 
headaches.