A cross-laboratory study of event-related gamma activity in a standard object recognition paradigm

This study proposes a standard paradigm for the investigation of visual information processing by means of gamma activity and presents a novel set of stimuli with a broad range of complex, coloured familiar real world and unfamiliar nonsense objects which are well matched with respect to physical stimulus properties. In order to demonstrate that the paradigm and stimulus set yield reliable results both were employed in two electrophysiological investigations in two independent laboratories. Participants were required to discriminate familiar from unfamiliar stimuli. The pattern of results was very consistent across laboratories. Early event-related potentials were not influenced by the stimulus type suggesting that physical stimulus properties did not confound object familiarity. Induced gamma band activity was stronger for familiar than for unfamiliar objects, supporting the notion of gamma activity as a signature of cortical networks underlying object representations.