The present invention provides devices, small interfering RNAs, and methods for treating a neurodegenerative disorder comprising the steps of surgically implanting a catheter so that a discharge portion of the catheter lies adjacent to a predetermined infusion site in a brain, and discharging through the discharge portion of the catheter a predetermined dosage of at least one substance capable of inhibiting production of at least one neurodegenerative protein. The present invention also provides valuable small interfering RNA vectors, systems, and methods for treating Huntington's disease in vivo without impairment of cell endoplasmic reticulum, spontaneous motor activity, or locomotor activity of a patient.