Systems and methods for diagnosing and treating various brain-related conditions, and/or for modifying at least one of cognitive, behavioral, or affective functions or skills in individuals. The method of diagnosing and treating a brain-related condition includes the steps of: (i) identifying at least a brain region associated with the brain-related condition; (ii) stimulating the brain region by employing at least one electrical, magnetic, electromagnetic, and photoelectric stimulus; (iii) optionally, stimulating at least one cognitive feature associated with the brain region; and (iv) optionally, subjecting the brain region to a treatment including at least one of cell replacement therapy, cell regenerative therapy and cell growth.