Fig. 1.

Schematic overview of DAergic modulation on LTP-like plasticity in the human motor cortex. This figure summarizes our previous findings about how activation of DA and its receptor subtypes, D1 and D2, modulate facilitatory, LTP-like plasticity induced by anodal tDCS (upper figure) or excitatory PAS (lower figure) in a dosage-dependent manner. tDCS hereby induces a more diffuse, while PAS results in a more focally restricted kind of plasticity. Red and blue arrows indicate the direction of plasticity; light red color bars represent the extend of plasticity under placebo medication, which is compared with plasticity under low, medium, and high dosage of global DA (dark green) as well as D1 (light blue) and D2 activation (light green) (Nitsche et al. 2006; Kuo et al. 2008; Monte-Silva et al. 2009; Nitsche et al. 2009; Monte-Silva et al. 2010; Thirugnanasambandam et al. 2011; Fresnoza, Paulus, et al. 2014; Fresnoza, Stiksrud, et al. 2014).