Sometimes our brains fill in our sensory voids

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Phantoms and ghosts are apparitions of spirit not real, and yet there is scientific support for such haunting and mysterious visitors.

To explain such spooky science, start with the normal human brain which receives signals from all five senses then develops new outgoing signals for some creative act. 

One example of such nerve circuits in action is hearing the tones of another singer and making the diaphragm to push air through vocal cords at just the right speed for perfect harmony. 

Another is visually sensing the distance from the basket, making muscles contract to send a basketball arching through the air into nothing but net. 

Now consider an instance where one kind of sensory input is diminished, such as in cases of blindness, deafness, or amputation. The brain will sometimes fill in with phantom images, sounds, and even body parts. 

Take, for example, phantom visions experienced by the blind called Charles Bonnet syndrome. 

It was first described in 1769 when Swiss naturalist Charles Bonnet described the hallucinations of his 89-year-old grandfather who, with failing eyes, saw strange patterns. 

Oliver Sacks, a famous neurologist, tells us that most people have swirling patterned hallucinations normally when we first close our eyes to go to sleep. 

Another example are phantom sounds heard by the hearing-deprived. Most of us experience hearing loss as we age, which begets ringing of the ears called tinnitus. Less common is musical ear syndrome, a complex form of auditory hallucinations. 

The great composers Robert Schumann and Dmitri Shostakovich both described hearing phantom symphonies in their heads from which they drew inspiration for composing music that we still hear performed today.

 Similarly, people who have lost a limb sometimes sense that the leg or arm is still there. This phantom limb syndrome can, unfortunately, become painful as the muscles of the imagined limb tighten and cramp. 

The limb may be fantasy, but the pain is real and too often unresponsive to standard pain medications and treatment. Recent promising research is bringing relief to those suffering from phantom limb pain by using mirrors reflecting the other actual limb in order to teach the amputee to unclench and relax the imaginary limb.

Imagine that! 

When there is loss, the human brain fills in with phantom images, sounds and limbs. And even though they are not part of the physical world, they exist in our minds and we need to deal with them. 

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