Welcome back. Last time we talked about how human communication works in relation to the brain and also how different parts of the brain are affected by traumatic experience.
This week we'll go a little deeper to discuss how the brain stores those experiences and how it adapts as a result of them.
The human brain is very plastic, meaning that it is capable of changing in response to patterned, repetitive activation. Reading, hearing a new language, and learning a different motor skill such as typing are all examples of the brain's plasticity in action. But not all parts of the brain are equally plastic.
As areas of the brain increase in complexity, they become more plastic. Image courtesy of Bruce D. Perry, M.D., Ph.D.
The Cortex Is the Most Plastic
The malleability of specific human brain areas is different. The most complex area of the brain -- the cortex -- is the most plastic. We can modify some cortex-related functions throughout life with minimal effort. For example, even a 90-year-old person can learn a new phone number.
The lower parts of the brain, which mediate core regulatory functions, are not very plastic. And that is for good reason. It would be very destructive for these basic and life-sustaining functions to be easily modified by experience once they were organized. A lesion that kills one million neurons in the cortex can be overcome. For instance, people recover language and motor skills following a stroke. Conversely, a lesion in the brainstem that killed as many cells would result in death.
Brain Plasticity Is Related to Two Main Factors
The degree of brain plasticity is related to two main factors: the stage of development and the area or system of the brain. Once an area of the brain is organized, it is much less responsive to the environment, or plastic. A critical concept related to memory and brain plasticity is the differential plasticity of various brain systems.