Disclosed are methods for regulating neurotrophin levels within a human body. The invention utilizes an implantable signal generator to deliver stimulation to neural tissue elements. Alternatively, an implantable pump may be utilized to delivery one or more drugs. The implanted device delivers treatment therapy to the neural tissue to thereby alter the level of neurotrophic factors such as BDNF expressed by the influenced neural tissue. A sensor may be used to detect various symptoms of a nervous system disorder. A microprocessor algorithm may then analyze the output from the sensor to regulate the treatment therapy delivered to the body. The invention describes a novel method to regulate the intrinsic levels of neurotrophins and may be used to treat patients with neurological and cognitive disorders.