“…This is perfectly justified in regard to the fact that neuronal network rhythmic activity at specific frequency bands is thought to contribute to information transfer and processing in the brain (Engel, Fries, & Singer, 2001;Fries, 2005). In fMRI-guided NF protocols, the target function is often the BOLD signal amplitude in well-defined brain regions (Caria & de Falco, 2015;Hellrung et al, 2018;Young et al, 2014;Zotev, Misaki, Phillips, Wong, & Bodurka, 2018;Zotev et al, 2011). However, a target could in principle be any function of possibly spatially (Koush et al, 2015;Ruiz, Buyukturkoglu, Rana, Birbaumer, & Sitaram, 2014) and temporally (Diaz Hernandez, Rieger, Baenninger, Brandeis, & Koenig, 2016;Ros et al, 2017) non-local dynamics.…”