Capacity of neurons and neural networks in the brain to change their connections and behaviour in response to new information, sensory stimulation, development, damage, or dysfunction. Rapid change or reorganization of the brain's cellular or neural networks can take place in many different forms and under many different circumstances. Neuroplasticity occurs when neurons in the brain sprout and form synapses. As the brain processes sensory information, frequently used synapses are strengthened while unused synapses weaken. Eventually, unused synapses are eliminated completely in a process known as synaptic pruning, which leaves behind efficient networks of neural connections. Neuroplasticity occurs during development in childhood, following physical injury such as loss of a limb or sense organ, and during reinforcement of sensory information such as in learning. Neuroplasticity forms the basis of research into brain-computer interface technology, in which computers are designed to interact with the brain to restore sensation in people with an impaired sense such as the loss of vision. Research on neuroplasticity is also aimed at improving scientists' understanding of how to reactivate or deactivate damaged areas of the brain in people affected by stroke, emotional disorders, chronic pain, psychopathy, or social phobia; such research may lead to improved treatments for these conditions.