“…A number of factors have been identified that influence the direction and magnitude of induced effects, including the age of study participants, their genetics, and their history of physical activity (Ridding and Ziemann, 2010). Although initial studies suggested TBS protocols were capable of inducing robust LTP and LTD-like plasticity in the human M1 (Huang et al, 2007;Huang et al, 2005), the response to stimulation can vary considerably between individuals (Hamada et al, 2013) and between studies (Di Lazzaro et al, 2011;Gentner et al, 2008;Goldsworthy et al, 2014a, b;Goldsworthy et al, 2012a, b;Hasan et al, 2012;McAllister et al, 2011;Todd et al, 2009;Vallence et al, 2013;Zafar et al, 2008). Most studies use a standard MEP amplitude of ~1 mV to probe the plasticity response to TBS.…”