# Pragmatic representations of self- and others’ action in the monkey putamen

## TL;DR

The monkey putamen encodes self- and others’ grasping actions during social interactions, relying on the potential for real interaction rather than just visual input.

## Contribution

This study identifies the putamen's role in encoding self- and others’ actions during social coordination, emphasizing the importance of interaction potential.

## Key findings

- Putamen neurons selectively encode the monkey’s and human’s grasping actions during a mutual action task.
- Encoding depends on the possibility of interaction, not on visual observation of the partner’s action.
- Grip type is encoded only when the monkey is performing the action.

## Abstract

Social coordination in primates relies on parieto-frontal networks encoding self- and others’ actions. These areas send convergent projections to the putamen, but its role in representing self- and others’ actions remains unknown. We recorded neuronal activity from anatomically characterized putamen regions of two male macaques during a Mutual Action Task (MAT), where a monkey and a human took turns grasping a multi-affordance object based on sensory cues. Cortico-striatal synaptic input, indexed by local field potentials, mirrored known cortical dynamics during sensory instructions and movement, while single neurons selectively encoded the monkey’s action, the human’s action, or both. Grip type was encoded only during the monkey’s trials. Viewing the partner’s action was neither necessary nor sufficient, as neurons fired even when it occurred in darkness but not when viewed through a transparent barrier. Thus, the possibility for actual interaction characterizes the pragmatic role of the putamen in gating cortical representations of self- and other’s actions in social contexts.

Neural mechanisms underlying coordinating one’s own actions with those of others are not fully understood. This study shows that neurons in the monkey putamen encode one’s own and others’ grasping actions. Activity depends on the possibility of real interaction, not vision alone, revealing a key role for the putamen in social action coordination.