Configuration of the action observation network depends on the goals of the observer

Observing the actions of others engages a core action observation network (AON) that includes the bilateral inferior frontal cortex (IFC), posterior superior temporal sulcus (pSTS) and inferior parietal lobule (IPL) (Caspers et al., 2010). Each region in the AON has functional properties that are heterogeneous and include representing the perceptual properties of action, predicting action outcomes and making inferences as to the goals of the actor. Critically, recent evidence shows that neural representations within the pSTS are sharpened when attending to the kinematics of the actor, such that the top-down guided attention reshapes underlying neural representations. In this study we evaluate how attention alters network connectivity within the AON as a system. Cues directed participant's attention to the goal, kinematics, or identity depicted in short action animations while brain responses were measured by fMRI. We identified those parcels within the AON with functional connectivity modulated by task. Results show that connectivity between the right pSTS and right IFC, and bilateral extended STS (STS+) were modulated during action observation such that connections were strengthened when the participant was attending to the action than goal. This finding is contrasted by the univariate results, which no univariate modulations in these brain regions except for right IFC. Using the functional networks defined by Yeo et al. (2011), we identified the parcels that are modulated by the attention to consist mainly of the fronto-parietal control network and default mode networks. These results are consistent with models of top-down feedback from executive system in the IFC to pSTS and implicates a right lateralized dual pathway model for action observation when focused on whole-body kinematics.

Automated summary

Observing the actions of others activates a core action observation network in the brain, which includes inferior frontal cortex, posterior superior temporal sulcus, and inferior parietal lobule. Each region within this network has different functional properties, such as representing the perceptual properties of action, predicting action outcomes, and inferring the goals of the actor. Recent evidence suggests that attention to the kinematics of the actor shapes neural representations in the posterior superior temporal sulcus. This study explores how attention alters network connectivity within the action observation network. The findings show that connectivity between the posterior superior temporal sulcus and the inferior frontal cortex, as well as bilateral extended superior temporal sulcus, is strengthened during action observation when attention is focused on the action itself rather than the goal. The results also suggest that the attention-modulated regions mainly consist of the fronto-parietal control network and default mode network.