Neurocognitive mechanisms underlying action tool knowledge tasks: the specificity of tool-tool compared to hand-tool manipulation tasks

Abstract Our ability to use tools is heavily based on action tool knowledge, allowing us to specify the action required to use a tool. Action tool knowledge can be assessed mainly with two kinds of tasks, namely, tool-tool compatibility tasks (i.e., deciding whether two tools are grasped or manipulated in the same way) and hand-tool compatibility tasks (i.e., deciding whether a tool is correctly held in hand). While these tasks are used to assess action tool knowledge, recent data showed striking dissociations between these tasks in brain-damaged patients. In this study, we explored (1) the neural bases (Experiment 1; n = 34 healthy participants); (2) the neuropsychological dissociations (Experiment 2; n = 60 brain damaged patients); and (3) the potential cognitive mechanisms engaged during these two tasks (Experiment 3; n = 52 healthy participants). The three experiments provide convergent arguments by showing that both tasks are sharing common core computations supported by a left-lateralized brain network, but manipulation hand-tool task engaged regions outside of this brain network and is explained by visual imagery while manipulation tool-tool task is rather explained by motor imagery. Our results shed a new light on action tool knowledge tasks.