Multiplicative joint coding in preparatory activity for reaching sequence in macaque motor cortex

• Published in: Nature communications Vol. 15; no. 1; p. 3153
• Main Authors: Wang, Tianwei, Chen, Yun, Zhang, Yiheng, Cui, He
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 11.04.2024; Nature Publishing Group; Nature Portfolio
• Subjects: 631/378/116/2395; 631/378/2632/1663; 9/97; Behavior; Coding; Cognitive ability; Cortex (motor); Electrodes; Humanities and Social Sciences; Hypotheses; Memory; Microelectrodes; Motor task performance; multidisciplinary; Neural coding; Neural networks; Recurrent neural networks; Science; Science (multidisciplinary); Somatosensory cortex
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-47511-1

Although the motor cortex has been found to be modulated by sensory or cognitive sequences, the linkage between multiple movement elements and sequence-related responses is not yet understood. Here, we recorded neuronal activity from the motor cortex with implanted micro-electrode arrays and single electrodes while monkeys performed a double-reach task that was instructed by simultaneously presented memorized cues. We found that there existed a substantial multiplicative component jointly tuned to impending and subsequent reaches during preparation, then the coding mechanism transferred to an additive manner during execution. This multiplicative joint coding, which also spontaneously emerged in recurrent neural networks trained for double reach, enriches neural patterns for sequential movement, and might explain the linear readout of elemental movements. Understanding the link between multiple movement elements and sequence-related responses in the motor cortex remains elusive. This study reveals a multiplicative joint coding mechanism during motor preparation which transfers to additive during execution, potentially explaining the linear readout of elemental movements.