F. Frank LeFever
flefever at ix.netcom.com
Sat Mar 1 22:12:57 EST 1997
In <331700A0.1A00 at worldnet.att.net> CASSIDY-FELTGEN at worldnet.att.net
>Can anyone tell me what mechanism causes the rapid, brief headache
>when a cold substance is ingested quickly? Related to this is my
>question regarding the brain not sensing pain during brain surgery,
>a person's perception of headaches as localized pain within the brain?
>Is this a paradox or are headaches not actually occuring within the
Where one "perceives" a pain to be localized is often incorrect, even
when dealing with more accessible parts of the body--e.g. an arm or a
leg. Pain from ischemic heart muscle (heart attack) might be
"perceived" in the arm, etc., etc.
You correctly localize headache pain within the HEAD, but there is more
in your head than the "brain", if by brain you mean that complex mass
of (mostly) nerve cells. I believe the consensus is that the pain is
from blood vessels passing through or nearby (perhaps overdistended).
The mechanisms of headache DEVELOPMENT, however are complex and poorly
understood, and in most cases may involve much brain/blood vessel
interaction. The peripheral nervous system and the brain's connections
to the periphery may be involved: for example, stimulation of the
trigeminal nerve can cause a rapid proliferation of mast cells in the
dura (tough tissue covering the brain), and there are complex
relationships between mast cells, nitric oxide, dilation of blood
vessels, pain, etc.
Increased blood flow (in vessels penetrating the brain) in response to
mental activity appears mediated mainly by nitric oxide (NO), and I
have speculated on the possibility of an "overshoot" of this natural
process having pathological effects (e.g. at Society for Neuroscience,
New York Neuropsychology Group
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