Final answer:
The expansion of the brain area dedicated to a finger used for reading Braille due to sensory input taking over the visual cortex is an example of a. brain plasticity, which shows the brain's adaptability and functional reassignment.
Step-by-step explanation:
If a blind person uses one finger to read Braille, the brain area dedicated to that finger expands as the sense of touch invades the visual cortex. This phenomenon is an example of brain plasticity. The concept of brain plasticity, also known as neuroplasticity, refers to the brain's ability to change and adapt, either by reorganization or by creating new neural pathways, particularly in response to learning, experience, or following injury. In this case, the somatosensory cortex, which processes sensory input from the body, undergoes changes allowing the individual to enhance their sensitivity to touch, and this can even extend to recruitment of the visual cortex, which usually processes visual information. This reassignment of brain areas highlights the incredible adaptability of the nervous system.
Brain plasticity allows for the creation of new synapses, pruning of synapses that are no longer used, changes in glial cells, and even the birth of new neurons. Functional magnetic resonance imaging (fMRI) can visually demonstrate these changes by showing altered patterns of brain activity. This adaptability is not limited to early development but continues throughout life, allowing for significant changes and recovery of function, as seen in the expansion of brain areas responsible for processing tactile information in Braille readers.