Measuring Heart Rate in Freely Moving Mice

Area of Science:

• Physiology
• Neuroscience
• Biomedical Engineering

Background:

• Heart rate (HR) monitoring is crucial in cardiovascular research and other scientific fields.
• Existing methods for measuring HR in behaving mice can be expensive or technically demanding.
• Accurate and reliable HR data is essential for understanding physiological responses.

Purpose of the Study:

• To provide a comprehensive protocol for measuring heart rate in mice using electrocardiography (ECG).
• To describe the fabrication of custom ECG equipment and surgical implantation of electrodes.
• To offer user-friendly data processing tools and discuss HR data analysis.

Main Methods:

• Development of a step-by-step protocol for manufacturing ECG connectors and shielded cables.
• Surgical implantation of subcutaneously placed ECG electrodes for 2-channel differential recording.
• Utilization of MATLAB-based graphical user interface (GUI) tools for data acquisition and initial processing.
• Application of the protocol in the context of defensive reactions to analyze HR dynamics.

Main Results:

• Successful implementation of an inexpensive and easy-to-use ECG technique for up to eight weeks of repeated recordings.
• Generation of accurate and reliable heartbeat detection and HR calculation.
• Demonstration of the protocol's suitability for recordings challenged by ambient or device noise.
• Provision of tools that minimize the need for extensive coding knowledge.

Conclusions:

• The described protocol offers a practical and accessible method for long-term HR monitoring in mice.
• The provided tools and detailed guidance facilitate accurate data acquisition and analysis.
• This technique is valuable for interdisciplinary research, particularly in studies involving behavioral responses and physiological stress.