terminals, neuronal cell bodies, and dendrites (Ong & Mackie, 1999). However, recent studies have found CB1 in oligodendrocytes (Moldrich & Wenger, 2000; Rodriguez, Mackie, & Pickel, 2001) as well as in oligodendrocyte progenitor cells within the subventricular zones where post-natal glial proliferation occurs (Berrendero et al., 1998). Cannabinoid-mediated CB1 signaling has been shown to control post-natal subventricular zone oligodendrogenesis (Arevalo-Martin et al., 2007), and enhance oligodendrocyte (Molina-Holgado et al., 2002) and neuronal (Galve-Roperh, Palazuelos, Aguado, & Guzman, 2009; Harkany, Keimpema, Barabas, & Mulder, 2008) lineage cell survival during neurodevelopment. Thus, our findings of associations between CNR1 genetic variations and white brain volumes are consistent with the role of CB1 signaling in maintaining neural integrity and function.
