Even More Brain Plasticity and You
What is Brain Plasticity
Neuroplasticity* is the change and growth of neurons and their inter-connects through stimulus such as learning and experience.
This idea of Neuroplasticity was first proposed in 1892 by Santiago Ramón y Cajal, a Spanish physician, pathologist, artist, and Nobel laureate. Because his ideas were so revolutionary his theories were largely rejected for the next fifty years. The person who coined the term neural plasticity is the Polish neuroscience Jerzy Konorski.
The word "plastic" is used to indicate that the brain is flexible, malleable, and able to change as a result of environmental factors or via a concerted effort to institute that change.
Despite his ideas being roundly rejected by his scientific peers, today Santiago Ramon y Cajal is considered the "father" of the science of Neuroplasticity.
* also referred to as brain plasticity, cortical plasticity or cortical re-mapping
How the Brain Changes
Genetic factors determinate brain structure and function. So does the environment in which a person lives; e.g. that person's actions and that person's willingness to take on the "new."
- Shortly after birth. This occurs as the brain organizes itself.
- In the case of brain injury in order to compensate for lost functions or to maximize the functions that remain.
- Throughout adulthood: whenever something new is learned and memorized
This is the least contentious concept of the plastic brain. Of course, we all know that children learn. They learn to talk, to walk, to draw and associate color and shape. Perhaps the most amazing early development in childhood is the acquisition of language.
Acquiring language is a complex process. It involves the child associating parental mouth movement with sound and then attempting to replicate both sound and movement.
To determine how this occurs researchers made some startling discoveries.
- The number of synapses (connections between neurons) peaks before the age of two; after which they decline to a steady state.
- Brain metabolism reaches adult levels by the age of ten months and then exceeds adult metabolism.
- Infants are more perceptive to sound than adults thus being able to distinguish nuances in pronunciation that adults are not capable of hearing.
- Infants (before the age of five) are able to actively rewire their brains. This has been demonstrated when the left hemisphere (thought to be responsible for language) is absent or damaged. Research has shown that language skills can be "taken up" by the right hemisphere.
Post Injury Plasticity
A surprise discovery in the research of neuroplasticity is that the brain can activity associate a given function to a different location as a consequence of normal experience, brain damage or recovery.
In one instance, a surgeon in his 50s suffered a stroke. His left arm paralyzed, his rehabilitation included immobilizing his good arm and hand. He set himself the task of cleaning tables in the hospital cafeteria. Slowly, over time, the left arm "relearned" how to move. Eventually he learned to write and play tennis again. The functions of his brain killed in the stroke were taken up in healthy regions of his brain.
The brain can compensate for damage by reorganizing it connections between intact neurons. Stimulation via activity aid in this reconnection.
In a recent experiment a graduate student was offered extra credit if she allowed researchers to blindfold her for one week. Her task was to learn braille. Having been sighted all her life she had no prior knowledge of braille.
Prior to the lessons the student was subjected to a functional Magnetic Resonance Imaging scan (fMRI) and the regions of her brain mapped under various forms of stimulation. One of the regions mapped was the visual cortex. The purpose of this fMRI was to establish a baseline that scientists could compare a week later after she began to learn braille.
For the next week she spent four hours a day studying and practicing braille. Mid week her visual cortex was subjected to another fMRI and researchers discovered that her tactile senses were being augmented in the visual cortex area of the brain. e.g. the area of the brain associated with visual processing was taking on some of the tactile (touch) processing required of braille.
From time to time the back of her brain was subjected to ten minutes in a strong magnetic field. This procedure is known to temporarily hamper the functions of the brain exposed to that field.
After being subjected to the magnetic field the subject had a great deal more difficulty reading braille. She stated that it was if her finger tips had become less sensitive.
At the end of the experiment, after the blind-fold was removed, the subject stated that her visual perceptions were somehow changed; that things did not look the same as before the experiment, but she could not elaborate.
Two weeks later she was back to normal.
What the experiment proved is that under a change of stimulus the brain is able to "rewire" itself. In the process an area of the brain long known to help decode visual images was pressed into service to help decode the sensation of touch.
Art Kramer, Professor in the University of Illinois Department of Psychology, the Campus Neuroscience Program advises the following.
"Be Active. Do physical exercise. Aerobic exercise, 30 to 60 minutes per day 3 days per week, has been shown to have an impact in a variety of experiments. And you don’t need to do something strenuous: even walking has shown that effect. There are many open questions in terms of specific types of exercise, duration, magnitude of effect…but, as we wrote in our recent Nature Reviews Neuroscience article, there is little doubt that leading a sedentary life is bad for our cognitive health. Cardiovascular exercise seems to have a positive effect."
"Second, Maintain Lifelong Intellectual Engagement. There is abundant prospective observational research showing that doing more mentally stimulating activities reduces the risk of developing Alzheimer’s symptoms."...Ideally, combine both physical and mental stimulation along with social interactions. Why not take a good walk with friends to discuss a book? We lead very busy lives, so the more integrated and interesting activities are, the more likely we will do them."
Dr. Yaakov Stern is the Division Leader of the Cognitive Neuroscience Division of the Sergievsky Center states:
- "Lifetime experiences, like education, engaging occupation, and leisure activities, have been shown to have a major influence on how we age, specifically on whether we will develop Alzheimer's symptoms or not."
- "...stimulating activities, ideally combining physical exercise, learning and social interaction, help us build a Cognitive Reserve to protect us."
- "The earlier we start building our Reserve, the better; but it is never too late to start. And, the more activities, the better: the effect is cumulative."
In this instance "Cognitive Reserve" means more neurons, more connections between them and more mental capacity to stave off the decline associated with aging.
Michael I. Posner currently an emeritus professor of neuroscience at the University of Oregon.
"(W)e have found no ceiling for abilities such as attention, including among adults. The more training, even with normal people, the higher the results."
This is the forth in a series of articles discussing the new field of research called "Brain Plasticity."
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