Secrets of the Mind by V.S. Ramachandran
Secrets of the Mind with V.S. Ramachandran
The secret functions carried out by our brain first came into the attention of Dr. Ramachandran while examining the case of an amputee, Derek Steen, who lost his right arm above the elbow in a car accident. His condition garnered a curiosity in Ramachandran when he (Derek) reported that he had felt tingling and stroking sensations in his right arm (that was removed surgically) while shaving the left side of his face. This opened an opportunity for Dr. Ramachandran to study phantom limbs in detail. The Phantom Limb was one of the greatest mysteries of neuroscience up until the pioneering works of Dr. Vilayanur S. Ramachandran and his colleagues solved it with research and experimentations. The following study is a means to understand what Phantom Limbs are and what causes this phenomenon.
Literature Review
The journal article by has given a detailed description of the characteristics of phantom limbs. This article has indicated that up to 50-80% of amputees have reported cases of pains in their body part that was removed during amputation. These phantom sensations could range from a feeling of warmth to itching, electrical shocks, tingling, etc. The author has also stated that these sensations get exacerbated towards the distal parts of the phantom limb where feelings of acute pain, burning, and even stabbing could be felt frequently or intermittently.
These phantom sensations are not only found in amputees but also in people whose breasts, rectum, testicles, or eye had been removed surgically. Most often their diagnosis and assessment can get rather difficult as the victims of phantom limb pain (pain in a body part that is not present) usually hide these symptoms in fear of being ridiculed or considered as mentally disturbed. In the earlier days this phantom sensation or pain was considered to be the result of the emotional pain that the amputee was feeling due to the missing limb. But today this has changed.
Most often phantom limb pains are mistaken with residual limp pain or stump pain. But there is a clear difference between phantom limb pain and residual limb or stump pain even though they are very hard to recognize from each other. Residual limb pain or stump pain is the pain associated with the body part adjacent to the amputated limb. Their occurrence will be significantly related to the occurrence of phantom limb pains. But in all these cases, pains felt at the sight of surgical wounds are, without doubt, not a part of these phantom or stump pains even though they will occur in unison during the early phases of amputation.
The origin of phantom limb pain, according to this article, is clearly neuropathic. Damage to central or peripheral neurons can be the cause that triggers these phantom sensations in amputees. Therefore, the author has divided the cause of phantom limb pains into 1.Central Factors and 2.Peripheral Factors. And both of these categories attribute the cause of phantom limbs pains to changes or damages caused to the synaptic structure of nerve cells. Research has shown that these phantom sensations are seldom a result of psychological factors. Even though the gravity and severity of these pains can be easily aggravated by the victim’s mindset, they are not entirely caused by them.
The research done by was one of the pioneering works to state that the origin of phantom limbs is not psychological. They found empirical evidences proving topographical changes going in primate brains after the surgical removal of arms or legs. Human (or Primate) brains are significantly different from that of other animals in the presence of specialized areas in them. These specialized areas (distinctly organized topographical maps) are concerned with different sensory modalities . For instance, the visual domain alone has thirty different specialized areas, concerned with various functions, located in the brain.
One of neuroscience’s most celebrated misconceptions was that once these specialized areas are laid down (allocated) in fetal life they can’t be reorganized again. This concept led scientists to believe that recovery in the case of damaged nervous system was almost impossible. Also, this led them to think that neurological diseases are inherently difficult to treat. But the research conducted by shattered this presumption in neuroscience. New ways to utilize this information has been emerging in modern science since then.
The first evidence they had to back this theory (that new neural connections ‘can’ be made later in life) was the topographical maps of amputees. They found that (as in the case of Derek Steen) amputees were able to sense pain or trickling sensations in the missing body parts while touching or stimulating other parts of their body. This led the research by to believe that some other parts of the brain, that are concerned with facial nerves has overlapped the maps concerned with the arms of the amputee. So ultimately, new neural connections are possible.
This theory of the formation of neural connections in the case of amputees was able to explain all instances of phantom limb pains or phantom sensation ever recorded. Also, this theory was able to forgo the belief of psychological contributors in phantom limb phenomenon. This research was also able to throw an insight into the involuntary spasms (such as sharp clenching sensations) that torment these phantom limbs in amputees (also detailed in the documentary).
The entry in the periodical is a follow up of the findings of V.S. Ramachandran and William Hirstein. They also describe of a phenomenon called telescoping wherein the distal parts of the amputated limb appears to be located near or within the stump. They stated that this is probably due to the over representation of cortical magnification of limbs in the somatosensory cortex of brain. Cortical magnification determines the number of neurons in a visual cortex responsible for the processing of a stimulation of particular strength and size.
This article also has a pictorial representation of the somatosensory map of human brain which is insightful in understanding the tingling sensation in the phantom limbs of patients (such as Derek Steen) while stroking gently through the face. The somatosensory map shows that the sensory nerves for face in the somatosensory cortex are located adjacent to that of left and right hands. This is the primary reason why sensory nerves of face make new neural connections with the sensory parts of amputated arms. Therefore, a stroke down the left cheek of Derek Steen could give him a tickling sensation in his left arm that has been surgically removed.
Patients who have reported severe pain in the amputated limb prior to the operation are at more risk of experiencing intermittent phantom pains after the surgery. The intensity of phantom pains in these people can also be extreme. Pediatric amputees as well as people with congenitally absent limbs are less prone to phantom limb pains. There is also a detailed description of various forms of mechanisms that could be the probable cause of such sensations in amputees. They are categorized into 1.Peripheral Mechanisms 2.Spinal Mechanisms and 3.Cerebral Mechanisms.
Besides giving a detailed description of the mechanisms causing phantoms sensations or pains there is also entry about methods to prevent their occurrences. Providing preemptive analgesia is a viable form of treatment. This, according to the authors, is a good way by which the abnormal neural reorganization (in amputees) can be stopped. But for patients who have experienced severe preoperative pains, these changes might have already taken place . For them the treatment is often reduced to simple pain killers.
The journal article by contains a detailed description of the current practices to limit phantom pains and a summary of various treatments available as of now for phantom sensations. The “presence” of these phantom limbs need not always be of same size and shape. About 20% of the amputees have reported of feeling a shortened or telescoped (varying) phantom. And therefore, according to the authors, the treatment of phantom pains should be clearly defined and specific for a particular patient. Otherwise, any efforts directed in this regard shall go wasted.
There are now two different interventions available to effectively manage phantom pains. They are 1.Symptom specific pharmacological intervention and 2.Tailored psychological, physical, and behavioral paradigms . There also have been various surgical interventions that can be used successfully in certain patients. But the authors ascertain that their long term benefits are still not completely known. Some of the most common mechanism based treatments are 1.Surgical Stump Revision 2.Nerve ending alterations 3.Injections into nerve endings, etc.
Some of the successful psychological interventions used for the treatment of phantom pains are 1.Eye movement desensitization 2.Cognitive and behavioral pain management and 3.Hypnosis. Most of these psychophysical interventions are aimed at normalizing the cortical processes that are believed to be the reason behind phantom pains. These interventions are often integrated with other approaches such as surgical strategies to provide better results.
Another viable tool to cope with the issues of phantom pain is the use of prosthesis. Most amputees who use prosthesis have reported to be able to embody the prosthesis in the void left by their amputated limb. This feeling of embodiment has eventually depreciated their phantom pains and, sometimes, even helps them to control these prosthetic limbs. Another viable option is movement therapy. But the difficulty in this is that this method only works for some people while the others report exacerbated pains after the therapy.
The article by is a detailed description of various experimentations that the authors have conducted and the reason for the inferences they made in this regard. The changes in the neural connections were first observed in monkeys 7 years prior to this article. Neuroscientists observed that adult monkeys, 11 years after dorsal rhizotomy (destroying problematic nerve roots), showed that the region in cortical somatotopic map corresponding to the hand can be activated by stimulating its face. This was the first evidence of massive reorganization of brain topography in these regions. This raised the suspicion that a similar change might be observed in human subjects as well.
This was in fact proved after conducting tests in a number of patients who had been experiencing phantom pains. The results were positive. About 8 of the 18 patients tested reported a similar sensation in their limbs for stimuli to their face. There was also a topographically organized map of their hand in the lower face. This was a groundbreaking discovery. Even though there have been previous observations that phantom sensations can be stimulated by providing stimuli to other parts of the body, the existence of an exact topographical map was unknown. This opened a new concept called remapping hypothesis.
Another important entry in this article is the explanation that the authors have given for synthesia in amputees. For long, many patients (amputees) had complained about the vivid voluntary movements executed by their phantom hand that sometimes lead to painful outcomes. But this becomes problematic in patients when they experience very painful involuntary clenching spasms that do not stop. Ramachandran was able to curb these pains by using a technique that involves mirrors. This method has been proved to be effective in other patients as well.
The studies conducted by the authors have come to redefine the presumptions that ruled neuroscience for long. Two results that emerged from these experimentations were 1.That the neural topography of primate brain is not static and is extremely labile 2.That the findings allow neuroscientists to relate subjective sensations to activity of brain maps which could prove to be very helpful in testing some of the celebrated assumption in neuroscience .
The documentary Secrets of the Mind by V.S. Ramachandran was first aired in 2001 almost two years after his postulates rocked the world of neuroscience with its revolutionary findings. It was the curiosity of V.S. Ramachandran about Phantom limbs that brought him so far into the mysteries of brain that he later came to be called as the Sherlock Holmes of neuroscience. Most often the case of phantom limbs was disposed off as a psychological phenomenon than as a neural anomaly because conventional neuroscience did not believe in the presence of a mental image of our body that was retained in our brain even after amputation. But according to Dr. Ramachandran, the entity that we call our body is not simply a physical presence. Experiments revealed that there is a mental map of our entire body located in a strip of somatosensory cortex located vertically along our brain. Even though the existence of such a part in the brain was previously known, the presence of a detailed corporal map was only proved with his works.
V.S. Ramachandran stated that the sensory parts concerned with the limbs (arms in most cases) are located very near to that of our face. It was previously believed that the neural connections once formed in the human brain were impossible to reorganize. But Phantom limbs were the first clue that V.S. Ramachandran found to contradict this belief. He found that the sensory parts of human face have taken over the amputated limbs sensory parts in Derek Steen. This was the reason why Derek was able to sense a stroking sensation on his phantom limb when given a stroke on his face.
Conclusion
The concepts postulated by V.S. Ramachandran created a series of revelations in neuroscience. The concept of ‘sensing’ was later recognized as only being a prelude to a series of operations happening later in our brains. A number of other cases (of his patients) helped him complete his journey into the secrets of mind to finally understand that only a very little part of our daily activities are actually under our control. The complexity of processes occurring in the nerve cells of our brain is even more complicated than what we previously believed. But now that we know a little more about it, V.S. Ramachandran hopes that one day we will be able to solve the mystery of the most elusive organ in living organisms, the human brain.
References
Flor, H. (2002). Phantom-limb pain: Characteristics, causes, and Treatment. THE LANCET Neurology , 182-189.
Giummarra, M. J., & Moseley, G. L. (2011). Phantom limb pain and bodily awareness: current concepts and future directions. Current Opinion in Anesthesiology , 524-531.
Kearsley, A., & Neil, M. J. (2011, June 27). Phantom Limb Pain. Anaesthesia Tutorial of the Week , pp. 1-7.
Rawlence, C. (Director). (2001). Secrets of the Mind by Dr. Vilayanur Ramachandran [Motion Picture].
Ramachandran, V., & Hirstein, W. (1998). The Perception of Phantom Limbs . In Brain (pp. 1603-1630). Oxford: Oxford University Press.
Ramachandran, V., & Ramachandran, D. R. (2000). Phantom Limbs and Neuro Plasticity. Arch Neurol , 317-320.
