Recording Forelimb Muscle Activity in Head&#45;Fixed Mice with Chronically Implanted EMG Electrodes

Amy Claire Kristl; Turgay Akay; Andrew Miri

doi:10.3791/66584

JoVE Journal
Neuroscience

This content is Free Access.

JoVE Journal Neuroscience

Recording Forelimb Muscle Activity in Head-Fixed Mice with Chronically Implanted EMG Electrodes

慢性的にEMG電極を移植した頭部固定マウスにおける前肢筋活動の記録

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05:43 min

March 29, 2024

DOI: 10.3791/66584-v

Amy Claire Kristl¹, Turgay Akay², Andrew Miri¹

¹Department of Neurobiology,Northwestern University, ²Department of Medical Neuroscience,Dalhousie University

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Overview

This study details a protocol for the hand fabrication and surgical implantation of electromyographic (EMG) electrodes in the forelimb muscles of mice. The aim is to record muscle activity during head-fixed behavior experiments to understand the differential control of movement by the primary and secondary motor cortices.

Key Study Components

Area of Science

Neuroscience
Electrophysiology
Behavioral Analysis

Background

Interactions between primary and secondary motor cortex influence muscle activity.
Both motor areas project to the spinal cord, but their differential influence on movement is unclear.
The use of forelimb muscle EMG provides insight into muscle activity during different movements.
Large-scale multi-electrode arrays enable the simultaneous recording from many neurons.

Purpose of Study

To compare the effects of inactivating primary and secondary motor cortex on forelimb muscle activity.
To determine how these regions differentially control movement across various muscle activity states.
To utilize EMG measurements alongside neural recordings to better understand motor control.

Methods Used

The protocol involves both the fabrication of EMG electrodes and their surgical implantation in mice.
Mice are used as the biological model to examine muscle activity and motor cortex interactions.
Details include precise surgeries and knot-tying techniques for secure electrode placement.
The timeline includes careful step-by-step instructions for electrode preparation and implantation.
All implanted electrodes were functional, producing clean EMG signals shortly after implantation.

Main Results

The study successfully demonstrates the functionality of implanted electrodes in recording muscle activity.
Findings indicate that direct motor cortical influence on muscles varies with motor behavior and muscle states.
Electrode performance was validated over time, with some electrodes failing after prolonged periods.
The approach enables detailed examination of the interactions between motor cortical areas and muscle responses.

Conclusions

This protocol provides a reliable method for recording muscle activity essential for dissecting motor control mechanisms.
While multiomics analysis was not applicable here, the work contributes to understanding neuronal interactions in motor control.
The findings have implications for further studies on the plasticity of motor systems and their roles in movement disorders.

Frequently Asked Questions

What are the advantages of using EMG electrodes in this study?

EMG electrodes allow for direct measurements of muscle activity, providing insights into the functional role of different motor cortical areas in movement.

How is the electrode implantation performed?

The procedure involves careful preparation of electrodes followed by surgical implantation into the forelimb muscles of anesthetized mice.

What types of data can be obtained through EMG recordings?

EMG recordings capture muscle activation patterns, which can be correlated with neural activity from the motor cortex, revealing insights into motor control.

Can this method be adapted for other muscle groups?

Yes, while this study focuses on forelimb muscles, the protocol can be adapted for other muscle groups depending on the research question.

What are potential limitations of this electrode implantation technique?

Challenges may include maintaining electrode stability long-term and the possibility of signal degradation or loss over time.

How do the findings inform future studies in motor control?

The insights gained can guide future research on the mechanisms of motor control and the relationship between neural circuits and muscle behavior.

What types of movements were investigated in this study?

The study explores various motor behaviors elicited during head-fixed tasks to assess how different motor cortices influence muscle activity.

このプロトコルでは、マウスの前肢筋に筋電図(EMG)電極を手の作製と外科的に移植して、頭固定行動実験中の筋肉活動を記録する方法について説明します。

私は、マウスの運動野(一次運動野と二次運動野と呼ばれる)が、さまざまな種類の運動中に互いに相互作用して筋肉活動に影響を与える方法に興味があります。したがって、一次運動皮質と二次運動皮質の両方が脊髄に投射することはわかっていますが、それらが運動にどのように異なる影響を与えるかは不明です。そこで、このプロトコルを使用して、一次運動皮質と二次運動皮質を不活性化した場合の運動中の前肢の筋肉活動への影響を比較し、運動がどのように異なる制御をしているかを理解しています。

前肢筋電図の使用により、さまざまな運動系領域の光遺伝学的不活性化が運動出力に与える影響を測定することができました。例えば、運動皮質が筋肉に直接及ぼす影響は、特定の運動行動やその行動中の特定の筋肉活動状態に特異的であることを示すことができました。ニューロピクセルのような新しい大規模な多電極アレイにより、複数の運動系領域にわたる大規模なニューロン集団から同時に記録できるようになりました。

これらの神経記録中にEMG記録を行うことで、これらの運動系領域間の相互作用が筋肉の活動状態にどのように依存するかを特徴付けることができます。