The brain is the organ of the mind. A biological view regards mental states, learning and behavior as products of brain function. Intelligence is a measure of how well the brain is functioning. Teaching is an intentional effort to constructively alter the brain function of students in a lasting fashion. While information is the pedagogical input to the student's brain, food and air may be regarded as the main input of chemical information into the student's body-brain system. If the food supply is biologically inappropriate or a child is hypersensitive and reacts inappropriately to food, dysfunction and disease are the result.
The increased presence of non-nutrient molecules in the blood stream in the form of additives, contaminants, toxins, and intoxicants makes brain dysfunction more likely and more difficult to interpret. Whenever humans are sick or influenced by food and/or airborne chemicals, their brain function is compromised and symptoms include disturbances of sensing, feeling, remembering and acting. Their learning is impaired and their behavior may be disturbed.
Bobner et al reviewed studies linking nutritional disorders with behavioral and learning problems in children. In their introduction they stated: "Millions are spent annually on special education programs for children whose severe behavior disorders prevent them from participating in the regular school setting despite average or above average intellectual capacity. A growing body of research indicates that some of these behavioral disorders are related to nutritional problems." Many factors are considered in the literature including nutrient deficiencies, toxic heavy metals and food allergy. A correlation between physical symptoms such as chronic rhinitis and recurrent otitis media and learning-behavioral problems suggests that delayed patterns of food allergy may underlie some learning disabilities. The principle food suspects are eggs, milk and wheat. Increasing numbers of children who are aggressive with antisocial behavior, and serious mood swings concern us. Sick children who behave badly create a ripple effect of disturbances in their families, neighborhoods and classrooms. Egger et al published studies showing the effect of foods on migraine headaches, epilepsy, and hyperactivity in children stated: "Taken together, the available research suggests that particular types of adverse food reactions sometimes correlate with neurological and psychiatric symptoms. The diversity of foods involved...is suggestive of allergy, and the adverse effects may correlate with immunological abnormalities."
Environment and ChemicalsResearchers from the Harvard School of Public Health suggested in 2006 that fetal and early childhood exposures to chemicals in the environment can damage the developing brain and can lead to neurodevelopmental disorders but warned that there is insufficient research to identify and avoid individual chemicals that cause brain injury. They described 202 chemicals that have the capacity to damage the human brain and concluded that chemical pollution may have harmed the brains of millions of children worldwide.
Concern about disease-causing effects of agricultural chemicals has been expressed for several decades. In 1982, for example, Alan Anderson reviewed the importance of nervous system toxins from the environment in causing mental malfunction. He stated: "Of the 100,000 or so chemicals used by American industry, 575 are deemed dangerous in large doses and many of these are known to be associated with catastrophic illness, from cancer to respiratory disease. Perhaps no class of chemicals is more subtle and treacherous in its effects, however, than neurotoxins, which can damage the nervous system even in modest doses and cause a variety of behavioral and emotional symptoms - among them, hallucinations, loss of memory, confusion, depression and psychosis." (Grandjean et al. Developmental neurotoxicity of industrial chemicals. Lancet.Nov. 8, 2006. Also see online Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA A Silent Pandemic: Industrial Chemicals Are Impairing the Brain Development of Children Worldwide. http://www.hsph.harvard.edu/neurotoxicant/appendix.doc )
Pruning Neural Networks
One; key feature of brain maturation and learning appears to be the pruning of connections that are not required. Pruning involves a scary process of cell atrophy and cell death. Neurons, like all cells, can self-destruct and some neurons die to allow other neurons to operate more efficiently. Pruning appears to occur in stages and continues at least through adolescence.
One idea of neuronal pruning is to make often-used brain circuits more efficient by removing circuits that are not being used. If a newborn baby does not use one eye, the cells that process information from the eye will disappear and sight from that eye cannot be restored later. These changes to brain structure are intense during the first 5 years of life, beginning with fertilization of the egg. There is both a rational plan of change and a random, lottery-like selection of features. The rational plan requires the best nutrition and best learning environment to proceed optimally. The random unpredictable aspect to brain changes may be just karma, working outside of any possible intervention.
You could argue that deficiencies in pruning are as likely to cause dysfunction as overly aggressive pruning. Mistakes in pruning circuits will leave disabilities in mental functioning; some will be obvious and others will be well-concealed. Autism is an example of disabling mistakes in brain reorganization in the first 3 years of life that result in lifelong disability. A final wave of circuit pruning in adolescence may account for some of the problems young people have adjusting to themselves and the world they live in. Not only is their body changing rapidly, their world changing rapidly but also their brain is reprogramming itself in midstream.
Maturation involves differentiation of mental ability, specialization and loss of the randomness that so characterizes children's activities. If neuronal programming is too vigorous, a promising youngster may level out and become a dull adult or a disease such as depression or schizophrenia may appear if important circuits are sacrificed or interfering circuits are not removed. During Phase 4 of synaptic pruning, during early youth to puberty, development the number of synapses is stable, however, synapse reorganization occurs. Phase 5 of synaptic development starts at puberty and is characterized by synaptic pruning; is has been suggested that up to 30% of synapses are removed. In the best case, this reorganization leads to a stable adult synaptic network. In the worst case, this pruning could disable the individual and lead to a diagnosis of schizophrenia or some other mental illness.