The Mirror Cure
We mentioned earlier that one reason you do not mimic someone or literally feel another’s touch sensations when you watch her being touched is that your prefrontal cortex inhibits your mirror neuron output. A second reason may be that when you watch someone else being touched, even though your touch mirror neurons are active, your skin receptors report the fact that they are not being touched, and this null signal prevents the mirror neuron activity from reaching the threshold of conscious experience.

But guess what would happen if someone were to numb your hand using an anesthetic? Astonishingly, we have found (in collaboration with U.C.S.D. graduate student Laura Case) that the patient now quite literally feels touch sensations in his anesthetized hand when he merely watches another person being poked. Or if the other person handles an ice cube, the patient feels the cold freezing his hand! Once you remove the touch signals from the intact hand, the patient does not merely empathize with others—he feels what they touch. The same thing happens in patients with phantom limbs. Watching another person’s hand being massaged seems to relieve pain in the patient’s absent arm or leg.

Clinically it is known that visual feedback using mirror reflections can help alleviate phantom pain and stroke paralysis, perhaps by tapping into mirror neurons. We are currently exploring whether illusions of disembodiment produced with mirrors can also be used to mimic the effects of ketamine and treat chronic pain syndromes by allowing a patient to “detach” from his body and the pain “it” experiences.

Extraordinarily, even real pain in a real arm can be cured through optical feedback. In particular, there is a cruel disorder called reflex sympathetic dystrophy in which a trifling injury leads to permanent excruciating pain, swelling and “paralysis” of an arm, a condition we have dubbed “learned pain and paralysis.” In 1995, in a lecture at the Society for Neuroscience meeting in San Diego, we suggested using mirrors to treat this disorder, and several large-scale clinical trials have since confirmed their efficacy. Even the swelling subsides—a remarkable example of mind-body interaction.

The strangest of body-image disturbances is one in which a perfectly healthy person desires to have an arm or leg amputated. In conjunction with our U.C.S.D colleagues David Brang and Paul McGeoch, we have found that touching the skin of the affected limb produces an abnormal sweating response, whereas touching the normal limb does not. Further, our brain-imaging studies indicate an impoverished representation of the affected limb in the right parietal lobe (the body image area), although the areas for touch in the somatosensory cortex remain normal. This discrepancy between accurate sensory input from the arm and a lack of arm representation in the brain creates a curious abhorrence of the limb [see “Amputee Envy,” by Sabine Mueller; Scientific American Mind, December 2007/January 2008].

Thus, studying people with brain abnormalities or manipulating sensory input in normal people using mirrors and other optical tricks can provide key insights into the way the right parietal lobe of the brain creates a vibrant image of one’s body that endures in space and time.

These observations have important implications, both theoretical and clinical. They suggest that what we call touch sensation, pain, the body or even the self results from a dynamic interplay of signals from three sources: sensory signals from the skin, muscles and gut; inhibitory signals from the prefrontal cortex; and input from mirror neurons, which respond to behavior that originates in neurons in other people’s brains! From this fluctuating mosaic of brain activity emerges your sense of an embodied self that is distinct from others and all your own.

This article was originally published with the title Hey, Is That Me over There?.

16 Comments

1. 1. tharriss 10:00 AM 4/13/10

   Interesting article, but in the future I'd suggest leaving out the attempts at comedy... at least when you choose politically charged targets.
   
   I love a good Palin joke as much as the next (non ultra-conservative) person, but all that does in this article is risk getting some readers upset and distracts from the science in the article.
   
   Thanks!

   Reply | Report Abuse | Link to this

2. 2. syncratio400 in reply to tharriss 12:43 PM 4/13/10

   Tharriss, most comedy comes at someone else's expense. The writers aren't trying to make friends, they are writing a scientific article in an entertaining fashion.
   
   You can have your opinion on how to write, but I'm fairly certain you aren't a professional writer. Leave your advice to your field of expertise.

   Reply | Report Abuse | Link to this

3. 3. jdlunsford 01:20 PM 4/13/10

   The paragraph describing RSD is horribly inaccurate. RSD can affect any part of the body (not just the arm), and the mirror treatment is a joke - ask anyone who actually has RSD. It's not something that can be treated with optical illusions.

   Reply | Report Abuse | Link to this

4. 4. jdlunsford 01:24 PM 4/13/10

   The paragraph describing RSD is horribly inaccurate. It can affect any part of the body (not just an arm). Also, the mirror treatment is a joke and it's efficacy in clinical trials is grossly overstated in this article. RSD is not a disease that can be treated with optical illusions.

   Reply | Report Abuse | Link to this

5. 5. NatureTM 01:33 PM 4/13/10

   When I read that about Palin, I sortof thought to myself, "Would she/her followers be insulted?" I concluded most wouldn't, and some may take it as a compliment. Any supporter of Palin and Tea Party politics must certainly be aware they are aligned with the gun rights and ownership subculture. Sarah Palin's shotgun is a symbol of freedom to these groups! I'm surprised I haven't seen any "Sarah Palin's perception of Shotgun ownership is fundamentally no different than Sarah Palin's perception of owning her own arm!" bumper stickers.

   Reply | Report Abuse | Link to this

6. 6. Spin-oza 04:54 PM 4/13/10

   Wow... such lame comments regarding the vacuous Palin versus the fascinating research that further establishes what many have known for centuries... and what the late Sir Francis Crick famously postulated: that we ourselves... and our notion of supernatural "souls" and contra-casual free will are in fact illusions, wholly instantiated by our (marvelously evolved) physical brains.
   
   Even a cursory review of either neruoscience or genetics would force any rational person, still able to think critically to arrive at that conclusion. From schizophrenia... to phantom limb syndrome... from autism spectrum disorder to obscession-compulsion disorders and addictions, the evidence is overwhelming.
   
   Any one still seriously entertaining the notion of a supernatural "free-willing" secret-soul-agent, somehow supervening on our physical brains, apart from natural causation... is well... rather "willfully" ignorant.

   Reply | Report Abuse | Link to this

7. 7. Marc Lévesque in reply to syncratio400 06:36 PM 4/13/10

   to syncratio400,
   
   Are you by any chance an expert on Internet etiquette
   
   :)

   Reply | Report Abuse | Link to this

8. 8. gwernymynydd 03:37 AM 4/14/10

   Thought provoking article. I know nothing about the subject and certainly not specifics such as RSD, but it raises the question as to what 'self treatment' could be feasible, how these findings could link with physiotherapy and whether a Wii program could be created to give pain relief or treatment.

   Reply | Report Abuse | Link to this

9. 9. jack.123 06:04 AM 4/14/10

   It's funny that the lame jokes are always the expense of the right,but never the left?

   Reply | Report Abuse | Link to this

10. 10. JamesDavis in reply to jack.123 07:53 AM 4/14/10

    "Jack", that is because the "right" is seldom, if ever "right" and the "conservative" is very seldom, if ever "conservative" and you always give a great deal of jargon to poke jokes and negative comments at...so get over it and if you don't like the jokes then change your behavior or learn to laugh at the jokes. After all, laughter is the best medicine and Palin consumes a lot of RSDs.

    Reply | Report Abuse | Link to this

11. 11. Wayne Williamson 06:50 PM 4/14/10

    Nice article...looks like they are on to something...(deleted my remaining comments;-)

    Reply | Report Abuse | Link to this

12. 12. capthecat 08:33 PM 4/14/10

    Can anybody give me a scientific explanation of what happens in the brains of people who have spontaneous out-of body experiences? Is there something that works differently in their brains? Some people think these experiences can be induced through relaxation techniques and I would be curious to know if any of you was able to experience OOB through relaxation.

    Reply | Report Abuse | Link to this

13. 13. jack.123 06:50 AM 4/15/10

    A short study of Buddhism,first working with relaxation techniques,then working with your with colors then objects,and you can work your way up to OOB's.Although it may only be a different state consciousness,but it like humor and beauty are in the mind of the beholder,but with practice,you will be amazed at the visions you can come up with.but it can take a few years to get there.As for scientific proof,I know of no brain scans while meditating going on right now,but it might be something someone should try to get grant for,but It would make for a great doctoral thesis.A faster way obtaining an OOB would be lucid dreaming,the technique is simple.Start keeping a daily journal of your dreams, the more you record the more you will remember,This is followed by giving yourself commands, before sleeping,and then focus on something in your dreams that would make you aware you are dreaming such flying,flying is a good one,because it's something that doesn't happen outside of a dream.I am of course speaking of doing so without an aircraft.When you first become aware in a dream,it can be quite an experience,at first it it short, but with practice you can stay in the dream longer and longer going to where you want and doing what you want uncluding OOB's.Good Luck.

    Reply | Report Abuse | Link to this

14. 14. anitalite 03:35 AM 4/17/10

    See how one can invoke a political discussion by dropping a political name in the midst of an article like this? That silly joke (that made me giggle a second) was cute until you nuts took it so far and diverted your thoughts and wasted energy into a messy and silly assault on one another.
    It was just a joke, maybe not appropriate for this, but funny none the less.
    Now, would anyone care to discuss their out of body experience? I thought that is what this article was about.

    Reply | Report Abuse | Link to this

15. 15. Tim Owers 05:33 PM 4/23/10

    I don't care about the odd joke here and there, the important thing is this article makes for an interesting read. My only criticism is the detail of the effects of Ketamine could have been �more fully explored. On page 1 you state:
    'Under its influence you empathize with your body the same way you empathize with other people, and you are able to simultaneously detach yourself from it'
    Under a low dose this may well be the case, under higher dosages the effect is far more dramatic. I now know this from personal experience.
    
    Seven days ago I was admitted to I.C.U. (post-operatively). In order to have an epidural inserted into my spine between the shoulder blades I was administered Ketamine. This is without doubt the scariest, most terrifying drug I have ever encountered. Whilst being physically conscious I was convinced I was underwater, in almost total (b&w) darkness, that I was dead, only able to talk in slow motion in a voice that was not my own and in total confusion at no longer having a body. Above all I was totally consumed by utter terror. The (chief) anaesthetist told me later he had never seen such an extreme reaction in all his thirty odd years, and had to very quickly make the decision to put me 'under' to override the Ketamine. In the short time it took to get the artificial respirator and all the other kit up and running I had an endotracheal tube inserted, which I then pulled out again. However, it wasn't me I was pulling it out of! There is of course a lot more than that I write here but I won't bore you with the whole experience, suffice to say, normal nightmares pale into insignificance to this.
    �
    Two days later I 'woke up,' which actually took about three hours to do, and the team were shocked that I could remember every single detail. Normally you remember nothing, or at most fragments. I wish that were the case for me as this is going to haunt me for the rest of my life.

    Reply | Report Abuse | Link to this

16. 16. bluewaitui 06:35 PM 10/3/10

    Interesting article. I am wondering about if research is being done or considered regarding if the mirror neurons are dammaged or undeveloped in individuals with Autism, psychopathic or narcissistic disorders. They all have a disability in their ability to put themselves in another's shoes.

    Reply | Report Abuse | Link to this