Which among the following is NOT a pain sensitive structure in the brain?

Relatively few cranial structures are pain-producing; these include the scalp, middle meningeal aery, dural sinuses, falx cerebri, and proximal segments of the large pial aeries. The ventricular ependyma, choroid plexus, pial veins, and much of the brain parenchyma are not pain-producing. Ref: Goadsby P.J., Raskin N.H. (2012). Chapter 14. Headache. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo (Eds), Harrison's Principles of Internal Medicine, 18e.