Marta Torrens1, Francina Fonseca2. 1. Addiction Research Group (GRAd), Neuroscience Research Program, Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain; Institut de Neuropsiquiatria i Addiccions, Hospital del Mar, Barcelona, Spain; Universitat Autònoma de Barcelona (UAB), Cerdanyola del Vallès, Spain. Electronic address: mtorrens@psmar.cat. 2. Addiction Research Group (GRAd), Neuroscience Research Program, Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain; Institut de Neuropsiquiatria i Addiccions, Hospital del Mar, Barcelona, Spain; Universitat Autònoma de Barcelona (UAB), Cerdanyola del Vallès, Spain.