Causative role of left aIPS in coding shared goals during human-avatar complementary joint actions.

Lucia M Sacheli,Salvatore M Aglioti,Vanessa Era,Matteo Candidi

doi:10.1038/ncomms8544

Abstract

Successful motor interactions require agents to anticipate what a partner is doing in order to predictively adjust their own movements. Although the neural underpinnings of the ability to predict others' action goals have been well explored during passive action observation, no study has yet clarified any critical neural substrate supporting interpersonal coordination during active, non-imitative (complementary) interactions. Here, we combine non-invasive inhibitory brain stimulation (continuous Theta Burst Stimulation) with a novel human–avatar interaction task to investigate a causal role for higher-order motor cortical regions in supporting the ability to predict and adapt to others' actions. We demonstrate that inhibition of left anterior intraparietal sulcus (aIPS), but not ventral premotor cortex, selectively impaired individuals' performance during complementary interactions. Thus, in addition to coding observed and executed action goals, aIPS is crucial in coding ‘shared goals', that is, integrating predictions about one's and others' complementary actions.

Highlights

Successful motor interactions require agents to anticipate what a partner is doing in order to predictively adjust their own movements
We tested whether two key nodes of the human fronto– parietal network, the left anterior intraparietal sulcus and the left ventral premotor area play any active, crucial role in the execution of imitative and non-imitative reach-to-grasp movements of healthy participants interacting with a virtual partner
Left anterior intraparietal sulcus (aIPS) has been widely associated with both goal-based motor control during movement execution[26], and with the coding of others’ observed action goals[27,28], becoming a good candidate to be the neural substrate of shared goal representation during motor interactions

Summary

Introduction

Successful motor interactions require agents to anticipate what a partner is doing in order to predictively adjust their own movements. Complementary interactions possibly rely upon neural substrates dedicated to link and integrate self and others’ movements and sub-goals in a single and coherent motor plan Such coherent integration is here defined as a ‘shared goal’ motor representation to prompt the idea that a joint action goal is both ‘in common’ between co-agents and ‘divided up’ into individual sub-goals that each actor needs to achieve to have the joint action fully accomplished. Despite the importance of complementary joint actions for social life, information about which brain areas may causally and selectively support the implementation of shared goals during online complementary interactions is lacking To explore this issue, we used an offline continuous inhibitory Theta Burst Stimulation (cTBS) protocol through which we temporarily inhibited the neural activity of the targeted cortical areas. Left aIPS has been widely associated with both goal-based motor control during movement execution[26], and with the coding of others’ observed action goals[27,28], becoming a good candidate to be the neural substrate of shared goal representation during motor interactions

Methods

Results

Conclusion