What do we now know about the brain, in a nutshell?
As with everything else there is diversity in brain architecture. The brain is a wonderfully complex organ, with 1000’s of distinct functional areas made up of 100 billion neurons, connected through 10 trillion connections, using 100’s of neurotransmitters, providing rich diversity. Indeed each brain is unique, highly plastic, dynamically changes over time, but has critical growth periods. The brain is shaped by genetics and environment. Some gene activitation is affected by the environment.
Brain processing and memory circuits are made of neurons and connections. Like muscle, connections are formed and strengthen with use. Neurons and connections are pruned when not used.
To start with, we will focus on two aspects of diversity which profoundly affect learning: brain hemisphere dominance and local verses global connectivity dominance. Hemisphere dominance determines a person’s predominate way of thinking and learning needs. People frequently have different brain hemisphere dominance for different tasks. There is only so much room inside the skull for white matter, so nature found the wisdom to vary both local and global connectivity.
Like other social mammals, humans divide their brains in two hemispheres, so that two different thinking tasks can go on at the same time, at different speeds. The fast visual or right hemisphere of the brain constantly scans for danger and performs non-linear critical thinking. The verbal left hemisphere specializes in communication and linear thinking. The hemisphere of the brain that dominates a person's thinking style is determined mostly by their genes. The two hemispheres frequently take the same information and process and store differently in the two separate systems. The combined effect is much greater than the sum of the two individually.
The brain only has so much room for connections, so a trade off is made between number of local connections verses the number of long distance connections. Local connections increase local processing and memory capability, whereas global increases coordination of different processing and memory circuits. Lower than average cross-hemisphere connections are correlated to high IQ.
Great scientists, leaders, and artists, such as Thomas Edison, Albert Einstein, Michael Faraday, Henry Ford, Charles Schwab, George Washington, Ben Franklin, Thomas Jefferson, Leonardo da Vinci, Ansel Adams, Pablo Picasso, Walt Disney, Steven Spielberg, frequently have strong right hemisphere and local connection dominance, at the expense of reading and sometimes social communication challenges.
Effect of modern lifestyle on the developing brain.
Unfortunately, modern mechanized sedentary lifestyles do not provide many activities to strengthen hemispheric connections, as there were in the past. Physical activity in dance, games/sports, and chores require parts of the body to cross over the midline, forming and strengthening connections. Once sections of the brain mylinate and neurons get pruned, establishing new functionality is more difficult, and processing and communication speed of these new circuits are greatly reduced.
Today, most US children under the age of three have a significant deficiency of a key brain element, Omega-3. The higher brain activity of the right brain increases the sensitivity to the deficiency, and frequently right brain dominate children are impacted by the deficiency until 9 years old or older. This is especially significant in roughly 30% of children labeled with dyslexia, and greater proportion of children labeled with ADHD and Aspergers/Autism.
The American Pediatric Association recommends that TV and electronic entertainment should be avoided for all children under age 2 and limited to no more than 2 hours a day for older children and teens, because of the abnormally high visual and verbal stimuli. Again, higher brain activity increases the susceptiblity to visual and audio overload, epileptic seizures, and brief losses of consciousness from TV and certain video games. Parents and guardians to be especially attentive with right brain dominate children and teens. The dynamics that grabs their attention can be harmful. Beneficial child-paced electronics adjust audio and visual dynamics to child's needs.
The immune system is a complex processing system tightly coupled to the nervous system. Weaknesses in one system, negatively impacts the other. Both impact development.