The pupillary light response has long been considered a reflex mediated by subcortical circuits (Loewenfeld,
1993; Gamlin & Clarke,
1995). This stands in contrast with other, typically smaller pupillary responses, which clearly depend on cortical processing: dilations with cognitive effort, with attentional load and perceptual decisions (Hess & Polt,
1960; Kahneman & Beatty,
1966; Einhauser, Stout, Koch, & Carter,
2008; Hupe, Lamirel, & Lorenceau,
2009; Nassar et al.,
2012; Wierda, van Rijn, Taatgen, & Martens,
2012), or constrictions with accommodation (“near response”; Marg & Morgan,
1949; Phillips, Winn, & Gilmartin,
1992; Bharadwaj, Wang, & Candy,
2011) and visual transients (“onset response”; J. L. Barbur, Harlow, & Sahraie,
1992; Young, Han, & Wu,
1993; Sahraie & Barbur,
1997). All of these secondary responses of the pupil are generally independent of the response to light and probably mediated by distinct pathways (Zhang, Clarke, & Gamlin,
1996; Wilhelm, Wilhelm, Moro, & Barbur,
2002).