“…Only select studies have evaluated all four ventricles (Driver, et al, 2010) while others reported lateral ventricle volumes only (Cardoso, Lachat, Lopes, Santos, & Colli, 2011;Kii, et al, 1998;Kii, et al, 1997;Su, et al, 2005). Additionally, previous quantitative work has often calculated ventricular area, rather than volume (Esteve-Ratsch, Kneissl, & Gabler, 2001) or used non-Beagle dog breeds, which are the most commonly used model for pharmaceutical use (Driver, et al, 2010;Ryan, et al, 2013;Vite, Insko, Schotland, Panckeri, & Hendricks, 1997). For the purposes of drug discovery, ventricle volumes, rather than area, may be more accurate due to increased sampling of the entire ventricle system, and the inclusion of the third and fourth ventricles in assessment may further identify potentially subtle changes in drug effects.…”