Brain Development and Executive Functioning
The brain develops in stages almost from the moment of conception, with different brain centers reaching maturity at different times. Brain centers include such areas as hearing, language, motor, and other sensory systems. The last brain center to develop is the prefrontal cortex found in the frontal lobes, the home of executive functioning and the sense of self.
Brain pathways develop when signals are sent through nerve cells or neurons. Each neuron has the potential for thousands of connections to other neurons. Information is sent from neuron to neuron across synapses using neurotransmitters, e.g., chemicals such as serotonin, dopamine, and norepinephrine. Each brain center, as it grows, develops many more neural connections than it will need at maturity. This provides the flexibility that enables humans to develop and learn in response to their environment. Once a particular brain center reaches maturity, the brain prunes away neural connections that haven't been utilized. This makes the early years of brain development particularly critical, as all parents know who spend time providing enriched environments for their developing offspring.
Brain development, especially through childhood and young adulthood, is part innate endowment and part development through exercise (Wade, 2004). In this way, the brain is much the same as the body. Not everyone can be a great athlete, but everyone can improve strength and coordination through exercise, and even someone with tremendous athletic endowment will never reach their full potential without hard work.
The more a brain center is exercised during its development period, the more neural pathways will be utilized. Once pruning has taken place, improvement in the functioning of a particular brain center is much more difficult. Anyone who has tried to master a foreign language can attest to this phenomenon. Two year olds learn their native tongue with relative ease, but fifteen year olds can struggle mightily to master even the rudiments of a second language.
Executive functioning involves the ability to size-up a problem, to come up with a plan to solve the problem, to reassess the plan over time as contingencies change, and to modify the plan as needed towards completion of the plan and resolution of the problem. Good executive functioning is akin to a well-run corporation.
Goldberg (2001) and others talk about the prefrontal cortex as being analogous to the CEO of the company. The CEO has to make the big decisions that will determine a company's future. To make these decisions well, the CEO must call upon all the resources of the company, the marketing department, new product development, accounting, systems analysis, etc. In much the same way, the prefrontal cortex is where the brain can examine working memory to develop well thought-out solutions to problems that take into account past experience, the full range of current options and an accurate assessment of the situation being addressed. When the prefrontal cortex is underdeveloped, the brain loses access to this higher-level information. Returning to Goldberg's CEO analogy, a company can hire the best and the brightest personnel, but if the CEO can't access the staff or disregards the information that staff provides, then decisions made will be based on faulty information and the result will be poor decisions at best and chaos at worst. Communication to and from the various brain centers and the prefrontal cortex is vital for optimal functioning. The prefrontal cortex has huge numbers of pathways to all of the centers of the brain.
With new windows into the brain provided by neuroimaging and other technologies, we now know that the last major growth spurt of the brain, fully wiring the critical prefrontal cortex, takes place around the ages 19 to 25. This frontal lobe development makes possible the kind of thoughtful reflection that is a hallmark of adulthood, in contrast to adolescent impulsivity and reactivity.
Children with neurophysiological challenges, or what we call the self-managementSM disorders, such as ADHD, Tourettes, obsessive-compulsive disorders, bipolar, and other learning and mood disorders are at particular risk for executive functioning difficulties later in life because those disorders often result in less than optimal prefrontal cortex development.
Research suggests that in some kinds of ADHD there is decreased activity in the prefrontal cortex leading to problems with impulsivity and difficulties in inhibition of responses (Barkley, 1997). Obsessive-compulsive disorders can have overactive frontal lobe involvement leading to too many thoughts related to feelings of alarm (Penzel, 2000). Language learning disorders can stem from too few pathways connecting to the prefrontal cortex, compromising executive functioning. (See Linda Narun's article). An under-discussed aspect of bipolar disorders relates to problems in thinking and problem-solving. But in all cases, and particularly in the case of challenged children, parents can play a large and positive role in helping their children maximize executive functioning capacity.
While prefrontal cortex development is completed in the early 20s, the capacity for executive function is available at younger ages to greater or lesser degrees depending upon the individual and how well the pathways have been established. Early establishment of these neural pathways is critical because around age 19, the brain prunes pathways in the frontal lobes that are not utilized, adapting itself to more efficient functioning. This is similar to consolidating routes using freeways rather than an elaborate network of farm roads.
The prefrontal cortex with its enhanced executive functioning is one reason for the big difference between the ways adults and adolescents react. Adults process emotions through pathways in the prefrontal cortex. Adolescents do not. Since the prefrontal cortex is where the brain is able to look at its own processes, this added step affords adults more cognitive mediation about feelings, helping to diffuse emotional reactivity and outbursts. The adult's response to frustration when dealing with a police officer or the boss will, hopefully, be more measured and thought-through than what might be expected of a 16 year old.
Effective executive functioning relies, first, on good scanning of the environment, both internal and external, to identify that there is a problem to be solved, e.g., "My heart is racing. I wonder what that is about?" Or, "Why are the cars ahead of me putting on their brakes?" Or, "Why is my friend so angry with me?"
Executive functioning looks to information provided by working memory in order to assess the possibilities related to the problem to be solved, and then to come up with a plan based upon the pertinent information. The prefrontal cortex, as CEO of the brain, must have a dynamic and fluid relationship with other parts of the brain that may hold the information that will allow a particular problem to be solved. According to Goldberg, "Memory based on such ever changing, fluid decision, selection, and switches is guided by the frontal lobes and is called working memory. At every point of the process we need to access a particular type of information which represents but a tiny fraction of our total knowledge" (p. 73). Linda Narun's article discusses what happens with individuals with ADHD or learning disabilities when these circuits to and from the prefrontal cortex are not working in fluid, dynamic fashion.
As children get older, our expectations for good decision-making are really about the prefrontal cortex and executive functioning. When parents ask in exasperation, "What were you thinking? Don't you remember the last time this happened?", they are actually inquiring into the functioning, or lack thereof, of the prefrontal cortex. Poor executive functioning is not necessarily related to scores on intelligence testing. Very bright people can manifest significant problems with decisionmaking, planning, and social situations. Good executive functioning relies on an integration of various parts of the brain, signals that go back and forth.
Returning to the CEO analogy, a company might have top notch new product development, marketing department and financial group, but with no one making decisions about how to deploy these assets, they are not used to move the company forward. This is why young adults who have the most difficulty leaving home and being successful in college are usually the ones with the most inadequate executive functioning. Having little internal executive function capacity, they have relied on others (school and parents) to do the job for them. Remove those props and these young people flounder. Drugs, alcohol, mood disorders, etc., add to the problems as judgment becomes even more compromised.
Executive functioning is a result of neural pathways in the prefrontal cortex, and early development of this skill results in greater adult capacity. Some kids are naturals and have been organizing the kids on the playground since first grade or pointing out to Mom while driving, "Both hands on the wheel, Mom." Parents can easily tell you which of their children they trust to be home alone, and which would tempt disaster. This kind of sorting is only partially related to ages of the children. Regardless of native endowment, development of executive functioning, which is essentially wiring the brain for the future, is enhanced by getting children actively involved in scanning and problem-solving from young ages. Encouraging selfmanagementSM encourages prefrontal cortex development.
The self-managementSM approach to parenting for executive functioning asks the question, "We leave in 10 minutes; what do you need to do to be ready to go?" The parent is assuming that time is a meaningful concept and that 10 minutes is translated to a time frame that is different than 30 minutes or 1 hour. With this as a given, the parent is then asking the child to scan internal and external states with the destination in mind and to come up with ideas for appropriate behaviors. Executive functioning is an integrative process that can break down easily if pieces are missing.
Let's use the example of getting ready to leave for school in the morning. The child has to go through an internal checklist which should include bodily functions, appearance, lunch, backpack with completed homework, jacket, and permission slip signed by a parent in order to go to the Children's Museum on Friday. The checklist would be modified if the destination is the mall on a Saturday. The child has to go through the checklist weighted against the notion of 10 minutes. "What do I need to do and can it be done in time to go?"
Helping the child to think through the answers, assessing whether they are realistic, and then mobilizing is about promoting executive functioning. Some children can tell you, "I have to go to the bathroom." The parent then asks, "What else do you need to do to be ready?" Through this approach, scanning and active problem-solving are encouraged. For young children, it is interactive with the parent supporting a process that is destined to become automatic. Automaticity is an important feature of effective executive functioning. The families that have a morning routine, with each member knowing the steps to leaving the house on-time, have a much easier go of it than the families who seem to wing it each day.
The child who when asked the, "We leave in 10 minutes. . ." question and responds, "I just need to finish this game," and then becomes oblivious to anything else that is needed is abdicating self-managementSM and inviting the parent to take over. Parents tend to do this automatically, providing good examples of executive functioning, but doing little to promote it in their children. It often sounds like, "Tim, turn that computer off right now, put on your shoes, comb your hair, brush your teeth, and get down here right now!" This same pronouncement may then occur another five times before anyone actually leaves the house. And when they do leave the house, usually it is in a state of tension and frustration with lots of last-minute efforts by parents to cover all the bases. "Get your backpack. Did you take your medicine? Did that permission slip get in your notebook?" In this scenario, the child does not consider time, and does next to no scanning of internal or external demands beyond the computer screen.
Child-parent interactions that over-rely on the scanning and processing abilities of the parents risk underdeveloped pathways in the prefrontal cortex of the child and with that, poorly developed executive functioning. These children can become the young adults who fail out of college because they couldn't get up in the morning, couldn't get to class consistently, couldn't track the assignments, didn't know how to study, never had to balance work and play with active decision-making about how to spend time, never had to remember to take their medicine, etc. The potential for breakdown in independent functioning is limitless.
Treatments for executive functioning disorders are in their early stages. Linda Narun's article addresses how computer technology has led to Fast ForWord and Interactive Metronome as intensive approaches to wiring pathways in the brain. These programs meet the child or adult at individual baseline levels and go from there, adding demands only when success at earlier stages has been achieved and become automatic. Practice, practice and more practice has to occur in order for new pathways to be established and become automatic. Practice also needs to occur to develop healthy social interactions as Dr. Roche discusses in her article. Pathways, to be truly useful, have to be integrated into the whole organization and generalized to related processes.
This process of growth and development of the prefrontal cortex is the marvel of the human organism. When executive functioning is impaired the process of habilitating a brain has to be slow and thorough in order to be effective. Taking a self-managementSM approach to parenting is the best way to optimize developing the pathways in time with the developmental processes of the growing child. Attention deficit disorders, learning disabilities, emotional traumas, and other challenges can interrupt and impair normal development. The experts at the Tarnow Center work to help parents and families to identify where the work needs to begin and how to maximize positive growth over time. Whether the individual is 2 or 67, we work with families to develop executive functioning much like any other aspect of healthy functioning.
Barkley, R. (1997). ADHD and the nature of self-control. New York: Guilford Press.
Goldberg, E. (2001). The executive brain: Frontal lobes and the civilized mind. New York: Oxford University Press.
Penzel, F. (2000). Obsessive-compulsive disorder: A complete guide to getting well and staying well. New York: Oxford University Press.
Wade, N. (2004). "Brains and brawn, one and the same." New York Times, January 25th.