It was largely accepted until fairly recently that the human adult brain was essentially fixed. This concept was illustrated in full-color diagrams confidently mapping the regions of and structures in the brain responsible for moving the left pinkie or for processing the feelings of biting your tongue. Every bit of neural real estate was zoned and assigned a specific function. So, it had to be true, right?
So, it had to be true, right?
Research in recent decades has overwhelmingly proven this not to be the case. Numerous scientific studies have confirmed that the brain is plastic, meaning it’s not fixed and not hard wired. The human brain is malleable, dynamic, and capable of physical change from birth until death.
Your Brain Is Constantly Changing
I like to think of our brain like a blob of Play-Doh. (See bog: The Play-Doh In Your Head) Every second of every day, we are shaping the mound with our behaviors, feelings, and thoughts and our environments, experiences, and the demands we repeatedly place on our brains physically sculpt it. This process, called neuroplasticity, works both for us and against us. (See blog: Your Plastic Brain: The Good, The Bad, and The Ugly)
Plasticity was first demonstrated in an experiment with ferrets, who have identical wiring to the auditory cortex and visual cortex as humans except for one important factor, the timing. The basic human wiring exists at birth while ferrets grow this circuit after birth. Scientist interrupted the pathway in the ferrets so that nerves from the eye grew into the auditory cortex. The ferrets were then trained to respond to sounds and lights and “heard” the lights with parts of the brain that would normally process sound.
Brain Change Can Be Fast
In a later experiment by Pascal-Leone, sighted adults were blindfolded twenty-four hours a day for five days. The subjects spent their time learning Braille and performing various tactile and auditory activities and had their brains scanned before and at the end of the experiment. In the earlier scans, their auditory cortex showed normal activity upon hearing sound, and as expected, their visual cortices lit up when seeing and their somatosensory cortices buzzed when fingering Braille symbols.
After just 5 days of being blindfolded, their visual cortex became active when doing all of these things. In their brains, the cortical real estate that had been dedicated to seeing was now hearing and feeling. With no signals coming from the eyes, their brains reorganized to utilize the newly dormant areas for other functions.
A plastic brain causes the phantom limb experience because people who have lost a limb experience a brain reorganization. The part of their brain that formerly received input from the missing limb is taken over by neighbors on the homunculus, the portion of the brain responsible for the movement and exchange of sensory and motor information of the body. Because the face and hand are side by side on the homunculus, one man missing a hand learned where to scratch his face to satisfy an itch on the missing hand.
In many cases, phantom pain has been shown to be caused by the last signal the brain received from the lost limb being in a confused endless loop in the brain. This phenomenon has miraculously been alleviated using mirrors which visually replace the lost limb and neuroplasticity to trick the brain into changing signals going to the brain.
Neuroplasticity Can Change Your Life
There is a catch to neuroplasticity though. It only occurs when a person is paying attention and focusing on the input whether it be intentional or not. Hence, with directed consciousness, a person has the ability to change their brain and their life for the better. However, unfortunately, neuroplasticity is most often accomplished unconsciously etching bad habits and patterns into the brain. (See blog: Your Plastic Brain: The Good, The Bad, and The Ugly)
The science of neuroplasticity is new with the limits unknown, but having a malleable brain opens up a world of possibilities. In a very personal sense, each individual has the power to change their life. On a broader scale, the same brains that now practice prejudice, hatred and warfare have the potential to be kinder, more compassionate and less aggressive.
It can happen one brain at a time.
image source: https://www.flickr.com/photos/22078151@N05/