Ecological Systems Theory was formulated by Urie Bronfenbrenner. His pioneering theory has profoundly shaped how our field views development.
Bronfenbrenner later added an additional element, the chronosystem, to the theory.
Sleep plays a crucial role in brain function, but we don’t exactly understand how this works. You can see neuron function changing during different types of sleep. The following presentation illustrates some of the most recent, and complex, science on the brain and sleep. He is essentially saying that sleep enables excited synapses to return to “homeostasis” or their pre-excitations levels. Therefore they do not remain hyper-responsive because of repeated wakefulness stimulation. Additionally, it is crucial for synaptic pruning.
A new study in the journal Molecular Psychiatry is getting some press. In the research, scientists found that stress induces changes to neural stem cells, causing them to form oligodendrocyte cells rather than astrocyte cells. The oligodendrocyte cells produce myelin which insulates nerve axons. This extra myelin, or white matter, disrupts the balance and timing of communication between neurons in the brain. Oligodendrocytes also play a role in forming synapses and the growth of axons. When stress alters the production of oligodendrocyte cells, it is physically altering the structure and potential connections within the nervous system. Not only does the extra production of oligodendrocytes have consequences, but the reduced number of stem cells that mature into neurons might also have later implications for memory and learning.
Scientists have known that stress results in physical changes in the brain, but these changes have frequently been measured at the macro level, looking at head circumference in babies, looking at the size of regions of the brain or the amount of activity in brain regions. This new study provides a clue into the mechanisms that create those observable physical changes, which result in observable behavioral changes. The results suggest the mechanism by which an individual may be predisposed to anxiety or mood disorders or reduced resiliency later in life. The research is very new, and we don’t know if the results will be replicated, but it presents huge potential for better understanding. Read a discussion of the article here. See an abstract of the study.
To follow up on the conversation in class regarding the non-existent link between autism and vaccines, you can read this Wikipedia article, which discusses the false research report and, not long before the “study,” how the researcher was paid tens of thousands of dollars by a lawyer’s group looking for evidence against vaccine producers.
Notice that the researcher, Wakefield, in partnership with the father of one of the boys in the study, had planned to launch a venture on the back of an MMR vaccination scare that would profit from new medical tests and “litigation driven testing.” The money he took from the lawyers wasn’t enough; he had planned to make even more money off his false results!
You can read just one of a series of articles on this in the British Medical Journal here.