Additional support for a tight relation between attention and saccades comes from neurophysiological studies. Indeed, in non-human primates, subthreshold microstimulation studies (Cavanaugh & Wurtz,
2004; Hanks, Ditterich, & Shadlen,
2006; Moore & Fallah,
2001; Schall,
2004), single-unit recording studies (Goldberg, Bisley, Powell, & Gottlieb,
2006; Ignashchenkova, Dicke, Haarmeier, & Thier,
2004), and transient inactivation studies (Lovejoy & Krauzlis,
2010; McPeek & Keller,
2004; Wardak, Ibos, Duhamel, & Olivier,
2006; Wardak, Olivier, & Duhamel,
2002) have emphasized that three brain structures, namely the Frontal Eye Field (FEF), Lateral Intraparietal area (LIP), and Superior Colliculus (SC), known to be involved in the control of saccadic eye movements, also contribute to the control of spatial attention. This was corroborated by transcranial magnetic stimulation (TMS) studies in humans (Chambers, Payne, Stokes, & Mattingley,
2004; Neggers et al.,
2007; Taylor, Nobre, & Rushworth,
2007). Finally, fMRI studies have shown overlapping activations in both overt and covert attention conditions (Beauchamp, Petit, Ellmore, Ingeholm, & Haxby,
2001; Corbetta et al.,
1998; Nobre, Gitelman, Dias, & Mesulam,
2000).