“…Some models have as few as three sources including baseline, source of interest, and noise (Della-Maggiore et al, 2002; Logan and Rowe, 2004; Marchini and Presanis, 2004; Baumgartner et al, 2000; Lu et al, 2003; Dimitriadou et al, 2004; Baumgartner et al, 1998; Beckmann and Smith, 2004; Bellec et al, 2006; Bullmore et al, 2001; Jahanian et al, 2004). Other fMRI simulation software use first principles of the MR physics (Drobnjak et al, 2006; Xu et al, 2007; Kim et al, 2008), bootstrap from real data (Bellec et al, 2009), or interpolate to introduce motion (Ardekani et al, 2001; Freire and Mangin, 2001; Pickens et al, 2005). Some of these are computationally demanding, requiring hours or days for a single simulation, others rely on existing fMRI subject data, and others are too simple or specialized to be of general use (see Sec.…”