# Microendoscopic calcium imaging in motor cortices of macaques during rest and movement

## TL;DR

This study uses calcium imaging to observe the activity of motor cortex neurons in macaques during rest and movement, revealing patterns of coordination and direction sensitivity.

## Contribution

The study introduces in vivo calcium imaging in deep-layer motor cortices of macaques to analyze neuronal activity during rest and movement.

## Key findings

- Calcium transients during arm reaches showed direction sensitivity in a subset of neurons.
- Some SMA and M1 neurons coactivated or exhibited sequential activation patterns during rest and reaches.

## Abstract

The study of motor cortices in non-human primates is relevant to our understanding of human motor control, both in healthy conditions and in movement disorders. Calcium imaging and miniature microscopes allow the study of multiple genetically identified neurons with excellent spatial resolution. We used this method to examine activity patterns of projection neurons in deep layers of the supplementary motor (SMA) and primary motor areas (M1) in four rhesus macaques. We implanted gradient index lenses and expressed GCaMP6f to image calcium transients while the animals were at rest or engaged in an arm-reaching task. We tracked the activity of SMA and M1 neurons across conditions, examined cell pairs for synchronous activity, and assessed whether SMA and M1 neuronal activation followed specific sequential activation patterns. We demonstrate the value of in vivo calcium imaging for studying patterns of activity in groups of corticofugal neurons in SMA and M1.

•One-photon calcium imaging in SMA/M1 during rest or arm reaches in macaque•We assessed dynamic activity in genetically tagged deep-layer cortical cells•Calcium transients during reaches showed direction sensitivity in subset of neurons•In SMA/M1, some cells coactivated or showed sequential patterns during rest/reaches

One-photon calcium imaging in SMA/M1 during rest or arm reaches in macaque

We assessed dynamic activity in genetically tagged deep-layer cortical cells

Calcium transients during reaches showed direction sensitivity in subset of neurons

In SMA/M1, some cells coactivated or showed sequential patterns during rest/reaches

Behavioral neuroscience; Systems neuroscience; Techniques in neuroscience