Cathodal transcranial direct current stimulation over the parietal cortex modifies facial gender adaptation

Previous studies have observed that prolonged adaptation to a face will bias the perception of a subsequent one. This phenomenon is known as figural or face after-effect. Although currently the topic of face adaptation enjoys utmost popularity, we still don't know much about the neural process underlying it. The aim of the present study was to determine, using transcranial direct current stimulation (tDCS), how the retinotopically organised primary visual cortex (V1) and higher-level, non-retinotopic right lateral temporo-parietal areas interact with facial adaptation processing. Seventeen healthy subjects received 10 min anodal, cathodal or sham stimulation over these areas during a facial adaptation task. Cathodal stimulation of the right temporo-parietal cortex reduces the magnitude of facial adaptation while stimulation over the V1 results in no significant effects. These data imply that mainly lateral temporo-parietal cortical areas play role in facial adaptation and in facial gender discrimination, supporting the idea that the observed after-effects are the result of high-level, configurational adaptation mechanisms.