Methods are provided for treating or preventing neurological symptoms and disorders which are associated with, e.g., lysosomal storage diseases. The methods include enhancing neuronal connectivity within the brain of a subject, increasing brain tissue volume, or preventing or delaying loss of brain tissue volume in a subject. Also provided are methods for monitoring the progression or regression of a neurological disorder, or assessing the onset of a neurological disorder, associated with a lysosomal storage disease, in which brain tissue volume of the subject is measured.