Decoding stimuli (tool-hand) and viewpoint invariant grasp-type information

When we see a manipulable object (henceforth tool) or hand performing grasping movement, our brain is automatically tuned to how that tool can be grasped (i.e., its affordance) what kind of grasp (e.g., power precision grasp). However, it remains unclear where visual information related tools hands are transformed into abstract representations. We therefore investigated different levels abstractness in processed: invariant the stimuli elicits (tool-hand invariance); and hand-specific but viewpoint-invariant (viewpoint invariance). focused on areas activated when viewing both hands, i.e., posterior parietal cortices (PPC), ventral premotor (PMv), lateral occipitotemporal cortex/posterior middle temporal cortex (LOTC/pMTG). To test for representations, presented participants with images videos (from first third person perspective; 1pp 3pp) inside an MRI scanner, cross-decoded versus grasps across (i) perspectives invariance), (ii) (iii) 3pp Tool-hand 1pp, not tool-hand 3pp, was found left PPC, whereas bilaterally PMv, LOTC/pMTG. These findings suggest abstractness–where stimuli-invariant representations/tool affordances viewpoint representations network.