(A) ASOs are currently administered by lumbar intrathecal injection and diffuse throughout the CSF and into the spinal cord and brain parenchyma. Multiple factors likely influence drug distribution and cellular uptake. Intrathecally-delivered ASOs are currently FDA approved for use in the motor neuron diseases SMA and ALS. (B) In the future, with advances in ASO chemistries and delivery technologies, ASOs may be delivered to the lateral ventricle and/or cisterna magna as well as systemically with the capacity to cross the blood-brain barrier.