The Brain Over Time
We’ve looked at the brain along the dimensions of energy, connectivity, activation and variability. We’ve considered the in/out Tone scale of sub-cortical/cortical.
The dimension of time is an important context for all the rest. The brains of an 8-year-old or a 70-year-old will likely show different energy patterns from those of an adult, and they can be trained differently. The developmental tasks and expected changes for different ages are also important to understand.
Development of the brain begins inside the womb, and the foundation of how a person at least begins to experience life occurs this early. The infant receives the same blood with the same chemistry as the mother. It’s commonly recognized that a mother who is drinking or smoking or taking drugs can have a lifelong effect on her child’s brain.
We are less aware that an anxious mother, a depressed mother, a safe and happy mother will also accustom the developing brain to related electro-chemical patterns and the cognitive and emotional styles related with them. Is nature or nurture more important in formation of the personality? This chemical inheritance suggests that “nature” is simply a reflection of the “nurture” in the mother’s life.
During gestation the fetus depends for everything on the mother—is literally a part of her body. Helpless in an unknown universe, the newborn learns how to live via that relationship. Children who don’t find safety and caring in the first months of their lives have a hard time ever finding it. We learn to trust and love—to attach ourselves intimately with another person—very early. Without that person to whom they are chemically bonded, some children simply don’t develop it—even if they have a caring and capable substitute family almost immediately.
In the early years of life, the brain has more neurons than at any other. It undergoes very rapid creation of synapses based on experience. There are regular periods of apoptosis—pruning the connections based on their usefulness. A more connected and functional network begins to develop in response to our experience. Energy patterns identifiable in an EEG may strengthen or shift or stabilize over years. With them, our personality—our gifts and challenges, general mood, learning style and so much else—becomes more fixed and complex.
The brain comes online from bottom to top, back to front and right to left. Although as adults we tend to consider the cortex, the frontal lobes and the left hemisphere most important, perhaps it’s a hint that the most immediately functional areas are sub-cortical, posterior lobes and RIGHT hemisphere.
We are born with the so-called reptilian and mammalian brains ready to roll. What they expect and watch for has likely been tuned in the womb, and it develops based on what the brain actually finds. The little animal beneath the “thinking” brain drives much of what we feel and do throughout our lives.
Cortical habit patterns, however, are built up over years of experience. As the outer cortical areas begin to take their role, there is a shift from slower to faster frequencies. There is the potential for greater inhibition and control of sub-cortical drives. Experience begins to take the place of curiosity as our outer brains tell us, “been there/done that.”
Learning is essentially the recording of any new experience by repeated firing of electrical signals through the related synapses. As the number of synapses grows, the brain grows; when we stop learning, the brain shrinks. That is a sign of aging that can happen at any age.
Psychologist Marian Diamond has provided a remarkable set of studies showing the effects on the brains of rats of experience, learning and social connectedness at any stage of life. Rats placed in an environment with little stimulation and little social contact had their brains shrink—regardless of age. Even old rats with small brains suddenly began growing, became more active and happy when they were moved into an environment where there were rats of various ages and new thinks to DO—not just watch.
One of the most common electrical signatures of aging in the brain is slowing in the peak frequency of alpha and often a generalized shift toward slower frequencies—especially in the left front. Training these issues when they are present can have a very positive effect on brain function—rolling back the clock.