Up until a few decades ago, the accepted scientific view was that the human nervous system is hardwired or fixed except in the very early stages of development. This fixed structure of the brain is based on our genetics and our early development determines our mental and physical capabilities. However, recent research is providing evidence to the contrary. We now know that the human nervous system is dynamic and is continually responding to intrinsic and extrinsic stimuli, changing its structure, function, and connections.
This inherent property of neuroplasticity involves the growth and the sprouting of axons and dendrites, the pruning and the strengthening of synapses, and even neurogenesis, the development of new nerve cells from stem cells. Importantly though there are adaptive neuroplastic changes that lead to a gain in function and maladaptive neuroplastic changes that can lead to a decrease in function, increase in injury or even pathogenesis.
This is entirely relevant to stress which is a strong stimulus for maladaptive neuroplastic change. On the other hand, aerobic exercise, mindful practice, education, learning new skills and other ways of dealing with stress actually promote adaptive neuroplastic change. What is fascinating is that functional MRIs are revealing that even with short periods of practice, there are measurable changes in the structure and the function of the brain. For example, there is an increase in the gray matter concentration in the hippocampus, a structure important in learning and memory. There is a decrease in the size of the amygdala paired structures that are important in our stress response and anxiety.
As we learn more about the mechanisms of neuroplasticity, particularly as they relate to stress, we are given the opportunity to actively participate in the ongoing processes that shape our brains and that alter our nervous system physiology and ultimately enhance our health and well-being.