“…Other intrinsic differences in protocols used to induce cortical plasticity in humans, e.g., stimulation mode or pulse frequency (Ziemann, 2004), may additionally contribute to differential findings between studies. We chose the PAS protocol (Stefan et al, 2000) for the present study as a frequently used and sensitive tool to investigate cortical plasticity and its relation to age and cognitive function in healthy subjects and neurological patients (Morgante et al, 2006;Weise et al, 2006;Frantseva et al, 2008;Muller-Dahlhaus et al, 2008;Castel-Lacanal et al, 2009;Fathi et al, 2010;Zeller et al, 2010;List et al, 2011List et al, , 2012.…”