Although we think that the adult brain remains formed and
static, we are finding that the brain changes and heals itself. Even early
psychologists like William James (1890) argued that our brain is flexible and
changing when he wrote The Principles of
Psychology. He called this “plasticity”.
But it took another 70 years to provide evidence for this concept. One of the
first pioneers was Joseph Altman who first discovered brain cell
regeneration—or neurogenesis—in 1962. More recently, by 1999 the psychologist Elizabeth
Gould of Princeton University reported that memories can be recorded in neurons
that are generated daily.
We are now in the age of bran plasticity. Neurologists and
psychologist accept the idea that the brain and its function are not fixed
throughout adulthood. Brain plasticity refers to the brain's ability to change
throughout life. We continue to learn because the brain keeps reorganizing
itself and forming new connections between brain cells. And we have come to
understand the method the brain uses to change. Donald Hebb in 1949 wrote The Organization of Behavior and
provided us with the Hebbian Theory which specifies that neurons that fire
together wire together. If I reward a behavior, my brain will associate that
behavior with the reward and encourage that brain connection. In the 1950,
after his father suffered a massive stroke, the New York neurologist Paul
Bach-y-Rita become interested in how the brain can receive information from
different organs. He invented an electrically stimulated chair. Behind the
chair, a large camera scanned the area, sending electrical signals of the image
to four hundred vibrating stimulators on the chair against the patient's skin.
The blind patient could “see” the diffuse image from the senses on his back. He
developed this technique into a tongue sensor that goes on top of the tongue
while wearing a camera that translates the image to these tongue sensors. The
tongue replaces the eye and receives the feedback that the brain “sees”. More
recently these techniques have been popularized by Michael Merzenich and Norman
Doidge. They developed the idea of both positive and negative plasticity.
We all appreciate positive plasticity. We develop memories
and learn new things. Our neurons and white matter that comprise our brain organize
in such a way that we form an internal representation of learning and
experiences. Representing multiple impressions of the same event under
different criterion (smell, look, feel, association, importance, relevance
etc.) With positive plasticity we learn new skills and improve our thinking by
developing better and more efficient communication between sensory and motor
pathways. But with negative plasticity we have followed exactly the same growth
but for the wrong outcome. We learn how to behave in ways that are not helpful,
and this is not intentional. Negative plasticity causes an increased sense of
pain, drug use and compulsive behavior among other negative behaviors. Pain,
for example, is generated in the brain, and the only way to stop pain is to
retrain the brain. Opioids lead to morphine and eventually leads to a situation
where no medication is able to stop the brain from feeling the pain. We have
retrained the brain to develop more neural pathways to feel the pain every time
we try and numb the pain by medication. The death of Prince and Michael Jackson
is a testament to how strong the brain is in feeling pain.
Stroke offers us a window into how fast and dramatic brain
plasticity can be. A stroke occurs when a part of the brain dies. It can be
caused by a blood clot or obstruction of an artery (Ischemia). Or alternatively
where a ruptured artery and the neurons are flooded (Hemorrhage). There are
other repercussions from these two events, with an accumulation of
fluid/pressure on the brain (Edema) and the disruption of the sodium-potassium
pump.
In the Copenhagen stroke study, a study headed by Henrik Jørgensen
from Bispebjerg Hospital, Copenhagen, Denmark reported that one in five stroke patients
died during hospital stay, one in seven were discharged to nursing home, and over
half of stroke patients were discharged to their own home. Half of those that
went home improved. What happens to these lucky quarter of the stroke victims
who improve is a testament about brain plasticity. With all strokes there is a
shadow that surrounds the dead tissue in the brain--penumbra. Penumbra are
cells waiting to die. Whether these cells die or recover is dependent upon how
fast the brain uses these cells for learning. And the clock is ticking. Every
minute of delay to treatment is said to cost a patient 1.9 million brain cells.
By early referral to physiotherapy,
occupational therapy, and speech language pathologist services the brain heals
itself.
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We have an ageist view of health. Instead of referring older
adults to therapy we instead shuffle them over to wards. Brain plasticity is
still available for older adults. But in our ageist view we judge older adults
as ready to die and we fulfill this judgement by not helping their brain become
re-engaged.
© USA Copyrighted 2016 Mario D. Garrett
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