1. A method of improving neuropsychological dysfunction in a patient suffering from an acquired brain injury disorder or a neurodegenerative disorder, the method comprising: identifying a patient suffering from an acquired brain injury disorder or a neurodegenerative disorder; measuring the patient's neuropsychological function; determining if the patient suffers from neuropsychological dysfunction based on the measurement; placing a delivery device on a target site in the ventral striatum, ventral capsule, or intersection of the ventral capsule and ventral striatum of the patient; activating the delivery device to apply an activation signal to the target site; and identifying improvements in the neuropsychological dysfunction in the patient based on the activation.