Category II: Clinical examinations: (1) Sallum et al. discuss the IGT and attention deficit hyperactivity disorder; (2) Xiao et al. combine the IGT and functional magnetic resonance imaging (fMRI) in order to investigate adolescent smoking behavior; (3) Singh describe the connection between sleep deprivation and IGT performance; and (4) de Oliveira Cardoso et al. provide a behavior-image study that investigates the correlation between frontal and cerebellar lesions and IGT performance.