Science explains the phenomenon of phantom limbs

Unlike other animals, the human being is still in the process of development when he is born.

That is why we are so defenseless, we need that protection from our parents and when we grow up we do not remember anything from our initial stage.

The first years of growth are vital for the correct formation of the nervous system and this implies the creation of new neurons and new connections between them.

During the first phases of growth, while we learn to walk or control some of our physiological functions, the nervous system is also adjusting to master these processes by establishing the correct connections between neurons.

Proof of this is that, if someone has one eye covered at birth and uncovered after a few years, that eye, despite being healthy, will be blind,

because the brain will not have learned to use it and will not be connected to it.

Similarly, but in reverse, when your brain has learned to manage and locate a part of the body, if it disappears, the brain continues to think that it is there, and this is a real problem for the sufferer.

The French doctor Ambroise Paré in the 16th century already described "sensory phantoms".

René Descartes also refers to this phenomenon in one of his works.

We owe the first rigorous description to Silas Weir Mitchell, the father of American neurology.

After the Civil War battle of Gettysburg, many patients were brought to the hospital, most with limb amputations.

Mitchell noted that of 90 amputees, 86 described sensations due to that limb, and he carefully noted the type of sensation, not just pain or itching, but also shrinkage or warmth.

It seems that the interest in this pathology arises from his friendship with the poet Walt Whitman.

During the war, Whitman went to look for his brother, wounded in Fredericksburg (State of Virginia).

As a result of that visit, he spent three years as a volunteer in a field hospital caring for and accompanying the wounded and collected many stories from amputated soldiers who spoke of the ghosts of their own flesh that returned to haunt them.

In chapter 108 of

Captain Ahab also describes that he still feels his amputated leg.

How does science explain these alleged ghosts?

Within our brain there are areas that regulate specific functions.

Certain brain injuries can cause us to lose taste, speech or mobility in a certain area.

In the same way, there are precise places that integrate the sensory information that we receive from a certain arm or leg.

What happens when we amputate that arm or that leg?

The brain still has the area that integrates the signals from that limb.

By no longer receiving signals from the peripheral limbs, this part of the brain that has ceased to function generates spontaneous discharges that are interpreted as pain, itching or discomfort.

Can a disease with such a complicated origin be treated?

Can painkillers be given to a member who is no longer there?

Traditionally it was about intervening on the stump, but obviously the problem is not there.

Pain medications have also been used, but unlike spot pain, chronic pain is difficult to treat.

The Indian physician Vilayanur S. Ramachandran devised an ingenious system.

He assumed that people who had paralyzed limbs prior to amputation were more likely to experience phantom limb pain.

This implied that for some time the patients had tried to move the limb, without success, which had created sensory feedback that stayed with them.

The pain was due to the fact that the brain interpreted that it should continue trying to move the limb that was paralyzed.

According to this, the therapy would consist of re-educating the brain to eliminate this supposed paralysis.

For that, he used a box with a mirror in which the healthy limb, through reflection, imitated the amputated limb and the brain interpreted that it was no longer paralyzed.

This mirror box therapy has had some success, although many studies describing the use of this therapy do not have adequate methodology, so its use remains controversial.

It is clear that the biggest box of surprises is not that of Ramachandran's mirrors, but our brain.

This mirror box therapy has had some success, although many studies describing the use of this therapy do not have adequate methodology, so its use remains controversial.

It is clear that the biggest box of surprises is not that of Ramachandran's mirrors, but our brain.

This mirror box therapy has had some success, although many studies describing the use of this therapy do not have adequate methodology, so its use remains controversial.

It is clear that the biggest box of surprises is not that of Ramachandran's mirrors, but our brain.

JM Mulet is Professor of Biotechnology.

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