Brain plasticity refers to the brain’s ability to adapt to a changing environment. In other words, it is the brain’s ability to compensate the loss of one sense by using other senses better.
When a person becomes blind, he loses the ability to transmit the sensory signals from the retina to the brain. Since the vision processing pathways are still intact, a person can still see subjective images by using data from touch or audition. This phenomenon is called sensory substitution.