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Author Topic: What is "pain" - how does the brain recognise it ?  (Read 15602 times)

Offline neilep

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Today my daughter decided to play a game. She decided to play that old classic ' Lets Pretend Daddys Toe is a Piece of Chocolate'...and so she decided to take a chomp....Fortunately I had just got out the shower !!(I'm sure this is rivetting yes?)...ok...here's my shpeel...It Hurt !!...no damage, just a tooth imprint:D  But I later thought, if it wasn't for the pain she may have bitten deeper !!...So, what is pain [?]... I can understand that it's a feeling of discomfort that can vary in intensity, I suppose it's like a sensory warning that prevents you from further harm eh ?..presumably there's a part of my brain that registers the pain and tells me it's pain yes ? I suppose the same can be said for any feeling ...pleasureable or not....

But there must be something really clever happening that differentiates nice feelings (caressing etc) and bad feeelings ? (a broken bone, or infection etc)..that's a clever bit of programming methinks.

I would appreciate your incites into pain, has anybody experienced excruciating pain ?

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« Last Edit: 03/05/2004 22:29:04 by neilep »


 

Offline Quantumcat

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Re: What is "pain" - how does the brain recognise it ?
« Reply #1 on: 03/05/2004 12:27:51 »
Well yes, pain is a feeling send from the offending body part that says to the brain 'something bad is happening to me please react!' and the pain you feel is that message ...

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Offline neilep

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Re: What is "pain" - how does the brain recognise it ?
« Reply #2 on: 03/05/2004 12:40:34 »
Thanks Erin...but how does it know which is a good feeling (pleasure) and a nasty one (pain) ?...how does the body know that something bad is happenning ?...there must be something inherent in the biochemistry that dissaccociates between the good stuff and bad stuff eh ?...it's how it knows this that I'm keen to find out.

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Offline Ylide

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Re: What is "pain" - how does the brain recognise it ?
« Reply #3 on: 03/05/2004 17:47:27 »
My understanding of how it works is this:  (docs feel free to chime in and correct me)

The nerve cells in your skin send electrical signals when exposed to pressure, heat, or cold.  The greater the magnitutde of the stimulus, the greater the electrical potential of the signal.  It's a stimulus/response function, so a higher electrical potential results in a higher level of pain, forcing you to take action that prohibits further expose to the painful stimulus.

Lower levels of heat, cold, or pressure are not interpreted as harm, and are not perceived with the same urgency by the nervous system, simply because of a lower electrical potential reaching the brain.  There's reasoning behind that old saying "a fine line between pain and pleasure"



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Offline neilep

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Re: What is "pain" - how does the brain recognise it ?
« Reply #4 on: 03/05/2004 18:29:07 »
Thanks Jay....presumably the nerve cells are the first port of call then, and it's from there that the appropriate signal is sent...the method of interpretation must be quite complex to differentiate between the myriad of physical sensations that the body can detect.



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Offline Donnah

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Re: What is "pain" - how does the brain recognise it ?
« Reply #5 on: 03/05/2004 21:37:10 »
Neil, I think there are different nerve ending for receiving pain than those that receive pleasure.  I'm digging from my brain archives here, and maybe I've confused it with hot/cold reception.  What say you Chris?

I've felt maximum pain the body can feel.  It felt like I was a glass thermometer and the red alcohol/silver mercury (I saw both) shot up to the top and shattered the glass.  Shards flew everywhere, and I could hear the walls reverberating with my scream.  I remember thinking "so this is what it's like to be tortured" before my mind decided it was leaving.  It took five people to hold me down, and I wondered what good could come of feeling that kind of pain.  Now I see it was all worthwhile to answer your burning question.  Thank you for giving my life purpose, Neil. ;)
 

Offline neilep

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Re: What is "pain" - how does the brain recognise it ?
« Reply #6 on: 03/05/2004 22:03:43 »
My Pleasure Donnah...or Pain..perhaps !!;)....Donnah..I'm intigued further now....what circumstances led to you feeling so much pain ?...you don't need to answer if it's painful for you to do so[:I](OUCH !!)

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Offline Donnah

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Re: What is "pain" - how does the brain recognise it ?
« Reply #7 on: 04/05/2004 04:38:11 »
A forcep delivery with no anesthetic.
 

Offline MayoFlyFarmer

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Re: What is "pain" - how does the brain recognise it ?
« Reply #8 on: 04/05/2004 06:39:47 »
c'mon neil you have kids, your wife would kill you if she knew you couldn't pick up on  that one!!getting back to the physiology of your questin.  Canabinoid had it for the most part exceept oneminor detail.  There is no difference in the electric potential of the stimuli, as all action potentials are equal in magnitude (action potential = nerve firing).  It is actually more a matter of which nerves are firing (are they heat sensors, pressure sensors, etc.) how many are being stimulated (lets you know if you're being pricked by a pin, or someone's finger) and the intensity (this is signaled by how fast the nerve fires, since it always fires the same strength). So you are right in your abreviated version neil that it is the sensory nerves themselves are the primary determinant.  however, since the nervous system turns electrical signals into chemical signals at the end of each nerve, remember that hormaones and other chemicals can have a huge effect on how these signals are interperated.  Besides the age old example of a person full of adrenaline sprinting for miles away from a predator, a good way to think of this is that certain things that often mean "pain" in the human mind can mean "pleasure" to the "certain people" at "certain times" ;)

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Offline neilep

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Re: What is "pain" - how does the brain recognise it ?
« Reply #9 on: 04/05/2004 10:58:32 »
Thanks Justy...I comprehend....another persons sugar is another persons sour eh ?..but I'm glad in my limited capability that I kinda had a grasp of it too.

Now..onto Child birth !!..in my own defence I did actually think of that after I put my post....I know the pain involved...I had a bunch of hairs pulled from my chest while wifey gave birth to sprog !!....and to be honest..I don't know what all the fuss is about !!! *tee hee....are you fuming yet Donnah ?*...(JOKE).....in fact I suppose this beg the question ,

If..most of the time, pain is there to warn us of something wrong...then why does it hurt so much to have a baby ?...you think a bio-chemical thingy might happen to make it a pleasure...but with all the assistance necessary to facilitate the birth.

DONNAH......HAPPY 1000 POSTS YAYYYYYY

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Offline Donnah

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Re: What is "pain" - how does the brain recognise it ?
« Reply #10 on: 04/05/2004 16:10:05 »
Thanks for the cheers Neil.  

Normally birth doesn't hurt that much.  Please don't think my delivery was normal.  It would scare the heck out of anyone (female) thinking of having a baby.  In the words of the OBGYN who was called in emerg. to deliver Steve, it was "barbaric" and "the worst possible delivery".  I had to disagree with him because my baby was healthy (although he spent his first four days in ICU).
 

Offline neilep

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Re: What is "pain" - how does the brain recognise it ?
« Reply #11 on: 04/05/2004 16:42:51 »
Well..by the looks of your son Donnah (unless you're only three feet !!)...he definitely has turned out fine...

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Offline bezoar

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Re: What is "pain" - how does the brain recognise it ?
« Reply #12 on: 05/05/2004 00:43:25 »
I read a great book once about a kid that was born without pain sensors.  Sounds great, right?  Wrong.  He ended up missing fingers and toes, and with all sorts of bad injuries from not feeling pain, and I think he died of some intra abdominal condition that would have been easily diagnosed if he'd been able to feel the pain.

As for the child birth stuff, thumbs down to Dr. Lamaze who believes that childbirth is perfectly natural and shouldn't hurt.  So here this organ in your body spasms and clamps down, and pushes out an object from your body that stretches and tears skin on the way out, but that's not supposed to hurt.  How'd that guy get out of medical school?  And worse yet, what about all the dumb women who bought into that theory?  Puuuhhhhllleeeaaassseeee!

Oh, and Donnah, you look just like I thought you would.  And what a handsome son.  You done good, girl!
« Last Edit: 05/05/2004 00:44:55 by bezoar »
 

Offline Donnah

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Re: What is "pain" - how does the brain recognise it ?
« Reply #13 on: 05/05/2004 01:00:56 »
Thanks Nancy.  And I think that men who say childbirth doesn't hurt should pass a cucumber through their penises.  I think my doctor left me in labor too long before he called the OBGYN.  Isn't 48 hours excessive?
 

Offline neilep

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Re: What is "pain" - how does the brain recognise it ?
« Reply #14 on: 05/05/2004 01:26:59 »
Nancy, after I posed my post I did a little research too, and I also found an article about people who are born without pain receptors.

It also mentioned the very same situation...about how the life span is dramatically reduced due to illnesses and injuries which never are discovered till it's way too late.

Donnah, OUCH !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Oh My !!!..I've got tears !!!!!!!...also...Sorry to make you put finger to keyboard, but what does OBGYN stand for ?...soz...is it something GYNaecological... ?

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Offline roberth

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Re: What is "pain" - how does the brain recognise it ?
« Reply #15 on: 05/05/2004 02:21:29 »
If I knew how to spell it, I'd say obstatrician and gynacologist, but I don't, so I wont. It's always the same isn't it? Women bringing up childbirth without any consideration for the effort involved in putting the baby in there in the first place. The poor male is the one who has to do all the work up front, just to cop the abuse at delivery time. C'mon girls, give credit where it's due!!
 

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Re: What is "pain" - how does the brain recognise it ?
« Reply #16 on: 05/05/2004 05:35:57 »
Okay, here's the overview on how pain is detected (nociception).



Nerves consist of a cell body, containing the nucleus, and a long thin cylindrical extension of the cell membrane called the axon. Information travels along the axon (which can be metres in length) in the form of action potentials - these are waves of electrical activity produced by an in-rush of sodium (Na) which carries the signal along the length of the axon.

At the end of the nerve fibre, the influx of sodium depolarises the nerve cell membrane and causes the nerve terminal to release chemicals, called neurotransmitters, which are stored therein.

These neurotransmitters then alter the activity of other nerve cells which have receptors for that transmitter, and so the message is passed on.

The body contains different classes of nerve fibres to convey different types of information. In general, the ease with which a nerve fibre can be activated (stimulated) is proportional to its size. So the largest fibres are the easiest to activate (have the lowest threshold for firing an acion potential) and also transmit action potentials the fastest. The largest fibres in the body are 1a fibres measuring up to 20 microns in diameter and conducting at up to 120 metres per second. These fibre types transmit 'fine touch' information - like the sensation you experience when running your han lightly over a table top.

Conversely, the smaller the fibre the harder it is to activate and the slower it conducts. Painful - nociceptive - stimuli are conveyed in the smallest fibres in the body called A delta and C fibres. They have a very high threshold for activation, measure 0.5 - 1 micron in diameter and conduct action potentials at up to 6 metres per second.

Usually you have to damage tissue to activate these nerve fibres. Interestingly, however, C fibres also express the receptor for chilli (capsaicin) and are responsible for the burning sensation that it creates.

When these fibres begin to fire off they convey action potentials to the spinal cord. In the cord a second nerve fibre transmits the signal to the thalamus in the brain, and from the thalamus a third nerve fibre tells your cerebral cortex (your 'conscious brain') about the problem going on in your little toe.

So that's how you become conscious of a painful stimulus, but if you watch people they actually react to pain before they become conscious of it. That's because the spinal cord, as soon as it senses a painful signal, also triggers off a series of protective 'withdrawal' reflexes.

Useful References about Pain :

Article by Prof. Peter McNaughton "What is pain & How to Control it"
http://www.thenakedscientists.com/HTML/articles/article/petermcnaughtoncolumn1.htm

Article about a novel painkiller derived from Cone Snail venom :
http://www.thenakedscientists.com/HTML/articles/article/barrygibbcolumn3.htm

Interview with Peter McNaughton (2000) "What is pain ?"
http://www.thenakedscientists.com/html/shows/2000.10.08.htm#interview

Interview with Peter McNaughton (2001) "Nerve cells and pain"
http://www.thenakedscientists.com/html/shows/2001.12.16.htm#interview

The Naked Scientists (BBC, 2004) "Chronic Pain" and how does acupuncture work ?
http://www.thenakedscientists.com/html/shows/2004.02.01.htm

Chris

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Offline Ylide

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Re: What is "pain" - how does the brain recognise it ?
« Reply #17 on: 05/05/2004 08:21:57 »
There was a series of problems of the MCAT based on using the withdrawal reflex to determine if there was injury to the left arm in a car accident by applying painful stimulus to each hand and measuring the force of the withdrawing reflex on the opposite side.  I knew something like that happened, I just wasn't sure quite how to explain it.  (having not had a single physiology class in my life)

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Offline neilep

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Re: What is "pain" - how does the brain recognise it ?
« Reply #18 on: 05/05/2004 10:53:39 »
CHRIS.....Thanks...that really covers it....and I even understand it too.:)

Roberth.. I agree....as I've said...regarding childbirth...I just can't see what the fuss is all about....and when the sprog is born, who get's all the attention ?  the girly !!...and all they've done is for the majority of the time just lay down, takeing the weight of their feet !

 Just like when you get married...it's always the girlies big day...the bridegroom is almost ancillary !!:)

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Offline Donnah

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Re: What is "pain" - how does the brain recognise it ?
« Reply #19 on: 05/05/2004 19:33:03 »
[xx(]
 

Offline tweener

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Re: What is "pain" - how does the brain recognise it ?
« Reply #20 on: 06/05/2004 03:57:39 »
Neil I think you should be glad you are on a different continent than Donnah.  She just might try the cucumber in YOUR penis - retrograde! [:0]

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Offline Donnah

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Re: What is "pain" - how does the brain recognise it ?
« Reply #21 on: 06/05/2004 15:36:47 »
John, shhhhh!  How do you expect me to catch him unaware now?  And I'm getting tired of carrying this cucumber.
« Last Edit: 06/05/2004 15:37:38 by Donnah »
 

Offline bezoar

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Re: What is "pain" - how does the brain recognise it ?
« Reply #22 on: 06/05/2004 19:27:35 »
You guys just say anything to get a reaction.  Kind of high school, don't you think?
 

Offline tweener

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Re: What is "pain" - how does the brain recognise it ?
« Reply #23 on: 06/05/2004 20:36:54 »
Absolutely!

But it's the only laughs I get!

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Offline neilep

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Re: What is "pain" - how does the brain recognise it ?
« Reply #24 on: 06/05/2004 22:30:08 »
Would a gherkin do ?

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Re: What is "pain" - how does the brain recognise it ?
« Reply #24 on: 06/05/2004 22:30:08 »

 

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