Today we would like to present you with the second of our series of guest bloggers. Allyson Mackey is a graduate student in the neuroscience program at UC-Berkeley. Enjoy!
I was recently challenged by a colleague to come up with an example of a
neuroscience finding that changed the way I live my life. I immediately thought of the now quite vast literature on
neuroplasticity: the ability of our brains to change and adapt to new experiences. In this post, I’d like to propose that what we’ve learned about neuroplasticity so far can help us lead better lives, and that neuroplasticity research in the future will be poised to influence public policy issues ranging from health to education.
I want to start by summarizing some exciting results from research on the structure and connectivity of brain cells, called
neurons. Scientists have shown that experience can drive changes in the connections between neurons in as little as thirty seconds. Substantial changes in brain inputs, like the loss of a sense like vision or touch in a limb, can lead to remarkable compensatory re-organization in
cortex. However, even subtle environmental changes can change brain structure. For example, giving rats interesting toys to play with, or allowing them to run more frequently on an exercise wheel, can lead to more connections between neurons in brain regions that are critical for learning, like the
hippocampus. What is even more exciting is that cognitive enrichment and exercise can lead to
neurogenesis, the creation of new neurons, in the hippocampus. The formation of new neurons was long thought to be impossible since, unlike other cells in your body, most neurons can’t divide to make more neurons after birth.
Unfortunately, neuroplasticity is often called a double-edged sword. While positive environmental changes can lead to beneficial neural changes, the brain is also susceptible to negative environmental factors. One particularly relevant example is stress. Chronic stress can prevent the birth of new neurons in the hippocampus, strengthen fear and anxiety circuits, and even effectively turn off brain regions responsible for attention and self-control. In summary, results from animal studies of neural plasticity suggest that our brains have the intrinsic ability to change in response to environmental demands both in adaptive ways, in response to cognitive stimulation and exercise, but also in maladaptive ways, in response to stress.