Watch the Imitating Bass Lines online guitar lesson by Larry Carlton from 335 Blues Motifs
So far in the course, the bass lines have stayed fairly stagnate without a lot of movement, primarily sitting on the root notes. However, in the case of the track that Larry is working with for this set of video lessons, the bass uses an interesting pattern that can inspire a variety of motifs and themes.
Larry demonstrates how to pick out a part of the bass pattern and reference that section for his motifs. You can use the actual notes that the bass player is playing, you can play them in higher registers, or you can just use the rhythmic qualities of the bass line and craft whatever melodic lines you wish.