CHANGING BRAINS
Better Understanding the Adolescent Brain
By Warren H. Chaney, Ph.D.
That brains differ between adults and children comes as no surprise. How much they differ - on the other hand - usually comes as a shock to parents encountering their sweet loving child’s teenage years for the first time. Parents usually account for the drastic changes with three words, “It’s their hormones!” I suspect that more is blamed on hormone change than research will support. Changes in brain development or the lack of (as some parents claim) – may account for more than we think.
Adults and Adolescents – Differing Brains
There isn’t a parent alive unfamiliar with the “special behavior” that teenagedom seems to engender. Doors slam, angry words exchanged, locked rooms, sulking, staying up till late and sleeping until noon when given the chance – these are more typical, than not. Then - there is the decision process. It is radically different during those adolescent years. To many parents they see their loving well-behaved child who wanted to be with them all the time morph into what appears to them to be an alien from another galaxy. Only trouble is, this alien lives at home.
The teen-age brain is relatively well developed except for a piece of brain tissue located right behind the forehead, called the prefrontal cortex. It combines the right and left frontal lobes and is the central part of the brain system that handles our complex decision-making. In teenagers, this system had not completely developed therefore the process is incapable of carrying out the kind of reasoning that enables most adults to make rational decisions.
Research has clearly demonstrated that while the teen’s body is almost completely grown by graduation, their brain is not. When this decision-making system underperforms, as it must – the quality of decisions suffer. It may lead a teen to choose a supersized 48-ounce sugar filled cola instead of milk or a more serious poor choice like stealing a car or taking drugs. It is these types of what appears to be irresponsible choices that lead adults to attribute rash decision making to teen behavior.
Teenagers may engage in risky behavior simply because their brains cannot perceive risk the same way adults can. Sometimes this adverse risk taking run afoul of the law. It is not for nothing that more seventeen year-olds commit crimes than any other age group.[i] However, given what we are learning about the teenage brain, there may be a need for lawmakers to revisit legislation surrounding incarceration of juveniles.
Many of our challenging decisions are made in the frontal lobe. We don’t require new decision making each and every time we drive to and from work. The brain soon has this activity stored and ready for replay. Yet, let a bicyclist dart in front of us and our brain’s decision-making system goes into overdrive, turning on quickly when need be. Unfortunately, a child or teen doesn’t have a complete working system to begin with. Insurance companies know this and that is why they price accordingly.
Fortunately, today’s imaging equipment (such as the fMRI (functional magnetic resonance imaging) lets us look inside an adult or young person’s brain in order to observe what is actually going on as the brain is functioning. Brain activity is determined by examining blood flow to the portion of the brain being used. Other equipment such as the PET Scan (Positron Emission Topography) performs similar tasks by measuring a brain’s fuel intake.
Brain scans combined with behavioral studies have revealed a great deal about the prefrontal cortex. We have learned that the same areas used for learning complicated rules and regulations, also applies them to differing situations.[ii] An adult suffering an injury to this area might understand that they must undress to go to bed. Yet, they may not realize that it’s inappropriate to do so as a guest in someone else’s living room.
We have learned that the prefrontal cortex brain system keeps us from letting our impulses get out of whack. One might feel like yelling at the boss, yet this important brain system keeps us from doing so.
An important study conducted by Dr. Silvia Bunge and her team at UC Davis found that children tend to make riskier choices that adults but do so because it’s enjoyable. When those in the research group were faced with different choices, the adults picked the safer choice while the adolescent often chose the riskier one. According to Bunge, the children knew they were making the riskier choice. Bunge was able to identify a region of the prefrontal cortex that was active, as the decision was being made but yet not as active as was the adult’s corresponding cortex. In other words, the teen’s region was active but not enough to keep them from taking the gamble.
Poverty – Brain Differences and Children
In a study recently published in the Journal of Cognitive Neuroscience, scientists said that normal 9- and 10-year-olds, differing only in socioeconomic status, have detectable differences in the response of their prefrontal cortex, the part of the brain that is critical for problem solving and creativity. This study emphasized the devastating effects of poverty on children's achievement. The study wasn’t a large one so we must be wary about its conclusions. Yet, the fact that it breaks new research ground gives us pause for consideration.
Few neuroscientists dispute the fact that children from more affluent families appear to have a “built-in” advantage over those less fortunate. At one time, it was thought the problem was a difference in financial opportunity. While that is still a factor, new studies have produced a major added difference. The brains of children from poorer homes are showing decreased activity in the prefrontal cortex as compared to similar age young people that have greater financial advantage.
Other studies have shown that the reasons for socioeconomic brain differences are because of the variability of a child’s life experiences.[iii] The experiences impact brain growth. On this count, we are all a result of these social interactions. Perhaps 30-40% of our brain is gene determinant but the remaining 60-70 results from our brain’s interaction with its environment.
Brain development in the first 2 years after birth is extremely dynamic. Total brain volume increases 101% in the first year, with a 15% increase in the second. Cerebellum volume increases 240% in the first year and the caudate increased 19% and the hippocampus 13% from age 1 to age 2.[iv] This is just a way of pointing out that there was robust growth of the human brain in the first two years of life. These results suggest a structural underpinning of cognitive and motor development in early childhood.[v]
While the new studies will be debated for some time, no one can deny that a wake-up call has been sounded. It isn’t that the young people are poor and because they are poor may have negative brain differences. It is that they are more likely to have health problems as well as potential problems from living in an environment that may not be brain friendly.
Summary:
Our brain changes dramatically from birth all the way through life, till death. During our younger years, our decision-making is challenged by a lack of brain maturity. Our brain’s environment constantly influences the brain’s mapping and growth. As we age, some studies have indicated that too much of our decision-making has been mapped causing us to become “set in our ways” and out of touch with current realities. The important issue to understand is that because the brain does constantly change being poor or disadvantaged is not a death sentence. With the proper intervention and training such as we experience at MTI with our Dynamic Mind Workshops, one will get an improvement in both the physical and cognitive behaviors.
[i] Tompa, Rachel, This is your brain on adolescence, Media Relations, October 16, 2008.
[ii] IBID
[iii] Mazziotta JC, Woods R, Iacoboni M, Sicotte N, Yaden K, Tran M, Bean C, Kaplan J, Toga AW; (2009) The myth of the normal, average human brain--the ICBM experience: (1) subject screening and eligibility. Members of the International Consortium for Brain Mapping (ICBM). Neuroimage.Feb 1;44(3):914-22
[iv] Knickmeyer, et al. (2008) A Structural MRI Study of Human Brain Development from Birth to 2 Years. The Journal of Neuroscience, November 19, 2008, 28(47):12176-12182.
[v] IBID
