Top-down effects of attention on the action observation network

Abstract

Action perception is one of the fundamental skills for survival and social interaction. In neuroscience literature, it is well-established that when an action is visually perceived, the Action Observation Network (AON) becomes active in the human brain. This network has three core brain regions: the posterior superior temporal sulcus (pSTS), parietal cortex, and premotor cortex. Recent studies in neuroscience have shown that action perception is not a passive process but is affected by top-down signals such as attention. In this study, we investigated the influence of attention on the AON by conducting a two-session fMRI experiment. The stimuli comprised eight videos of pushing actions, with each video featuring a unique combination of actor (female or male), effector (hand or foot), and target (object or human). In the active fMRI session, participants viewed the videos while performing three different tasks that directed their attention to distinct features of the action (actor, effector, target). In the passive fMRI session, participants viewed the same videos without performing any task. The data from the passive session was used to extract ROIs: pSTS, parietal, and premotor in each hemisphere. Univariate analysis, representational similarity analysis (RSA), and decoding analysis were performed. Univariate analysis showed that introducing attentional demands during video viewing elicited a significant increase in neural activity within both parietal and premotor cortices relative to passive viewing conditions. RSA results revealed significant correlations between neural activity patterns and task models across all ROIs, indicating top-down influence throughout the AON. Decoding analysis showed unique top-down effects in each ROI, depending on its hierarchical level and intrinsic selectivity. These findings demonstrate strong top-down modulation of the AON based on cognitive demands, highlighting the dynamic interplay of attention and action perception.