Computing Arm Movements with a Monkey Brainet.

Arjun Ramakrishnan,Miguel Pais-Vieira,Mikhail A Lebedev,Katie Z Zhuang,Yoon Woo Byun,Miguel A.L Nicolelis,Peter J Ifft

doi:10.1038/srep10767

Abstract

Traditionally, brain-machine interfaces (BMIs) extract motor commands from a single brain to control the movements of artificial devices. Here, we introduce a Brainet that utilizes very-large-scale brain activity (VLSBA) from two (B2) or three (B3) nonhuman primates to engage in a common motor behaviour. A B2 generated 2D movements of an avatar arm where each monkey contributed equally to X and Y coordinates; or one monkey fully controlled the X-coordinate and the other controlled the Y-coordinate. A B3 produced arm movements in 3D space, while each monkey generated movements in 2D subspaces (X-Y, Y-Z, or X-Z). With long-term training we observed increased coordination of behavior, increased correlations in neuronal activity between different brains, and modifications to neuronal representation of the motor plan. Overall, performance of the Brainet improved owing to collective monkey behaviour. These results suggest that primate brains can be integrated into a Brainet, which self-adapts to achieve a common motor goal.

Highlights

The neurophysiological mechanism underlying conjoint motor behaviour
During B2 and B3 operations, cortical ensembles in each monkey exhibited clear task-related activity during both passive observation (Fig. 5A,C) and brain control modes (Fig. 5B,D). Analysis of these neural signals confirmed that the accuracy of arm movement decoding would improve when VLSBA was recorded and combined from multiple brains (Fig. 5C). This finding extends our previous results, using neuron dropping curve (NDC) analyses, where we showed that decoding accuracy consistently improved when larger neuronal samples were recorded from a single brain[4,5]
We have successfully developed a shared monkey BMI that utilized chronic, simultaneous VLSBA recordings from pairs or triplets of primate brains to enact conjoint 2D and 3D movements of a monkey avatar arm

Summary

Introduction

The neurophysiological mechanism underlying conjoint motor behaviour. As such, the present study is the first to implement Brainets based on the chronic extracellular recordings of up to 783 individual cortical neurons distributed across multiple rhesus monkey brains. In the first experiment (shared control task, Fig. 1B), two monkeys worked together to move the avatar arm in 2D space. To obtain training data for brain control, we started each session with a passive observation epoch during which monkeys watched the computer-generated avatar arm movements along centre-out trajectories[38].

Results

Conclusion