Abstract
Areas implicated in tool and hand processing have typically been localized by contrasting pictures of tools and hands to pictures of animals, objects, or scrambled images during functional magnetic resonance imaging (fMRI). Dynamic stimuli like videos, however, may be advantageous as they are more engaging than pictures and can depict the complex interaction between an effector and its target. The purpose of this project was to determine whether videos are indeed more effective than pictures in identifying tool- and hand- selective activation. In two experiments, healthy participants were scanned as they watched videos and pictures. In Experiment 1, we compared a typical fMRI localizer with pictures of tools, hands, objects, and scrambled images (all in isolation, centred within a neutral background) to movie clips that showed tools interacting with objects, hands manipulating objects, objects in motion, and moving patterns (akin to a scrambled condition). The results from Experiment 1 demonstrated that videos activated a more extensive tool- and hand-selective network than traditional pictures (based on the contrast tool/handvideo – objectvideo) > (tool/handstatic > objectstatic). However, because there were numerous differences between the picture and video stimuli in Experiment 1, we ran a second experiment in which the stimuli were directly comparable. In Experiment 2, participants viewed the same categories of videos as in Experiment 1 or static frames from those videos. We again found much more extensive tool- and hand-selective activation for videos compared to pictures. Moreover, across both experiments, videos were more effective at identifying tool- and hand-selective activation in individual participants, making them more suitable as fMRI localizers (now publically available). We conclude then that videos are more effective than pictures at representing the action information evoked by observing the interaction between an effector and its target, especially in brain areas involved in actions and goal-oriented behaviour.
Meeting abstract presented at VSS 2017