The developing brain

In November 2014 Jane Roskams gave an insightful talk on ‘The Developing Brain: Implications for Youth Programs‘. She described recent findings from neuroscientific research and explained their relevance to the development of children and adolescents. This is my understanding of the rationale.

Previously it had been thought that, after birth, there were three windows in time which open and then shut for the sequential development first of our senses, then of language and finally of the higher cognitive functions. We now know that the windows do not shut fully. Some brain functions have a much reduced capacity for further development after early childhood: hearing, vision and emotional control, for example. But that capacity is reduced not removed entirely and for many other functions the brain retains a substantial capacity to continue developing through adolescence and beyond into adult life. Habitual ways of responding, the use of numbers, language and social skills are examples of the latter. In other words the so-called ‘neuroplasticity‘ of the brain is greater in childhood but it continues through life.

After we are born, our neurons grow by developing connections with each other – 100 billion neurons making many billions more connections. The pathways and circuits thus created are all driven by the life experiences outside of us and they keep changing throughout life. The growth is made possible by giving the neurons enough nutrition. But the chemistry of the brain is such that neurons change how they use their own DNA and genetic code in response to life’s experiences. The processes involved are part of a field of study called epigenetics. It has been found that our DNA is not our destiny: epigenetic changes, unlike DNA sequence, can occur rapidly as a result of dietary and other environmental exposures. How does this happen?

Neurons are a type of brain cell. Glia are a different type whose purpose is to protect, feed and carry out the housekeeping for neurons in order to keep them in good working order. There are many more glia than there are neurons. The chemistry of the brain enables the DNA to be accessed in certain ways, thus controlling how the brain changes as it learns and matures. Certain experiences including physical injury, infection and extreme stress can cause the glia to produce chemicals which alter the accessibility of the DNA. This can create a chronic state in the brain whereby it has a reduced capacity both to adapt to experience and to create new neurons (neurogenesis).

At the level of individual brain cells, the chemistry of each cell makes up an epigenetic signature. The signature can be read, rather like a barcode. Epigenetic signatures change by design at different stages of development and they are also changed by trauma (physical, emotional, chemical) chronic infection, environmental chemicals, drugs of abuse, stress or affection, exercise, diet and ageing.

epigenetic-environmentThe good news is that the right kind of support can bring about positive changes to offset the negative factors. The right kind of support and stimulation can have a big, positive effect on the epigenetic signature and thus enhance neuroplasticity and neurogenesis.