Development of a low-cost, comprehensive recording system for Circadian rhythm behavior

Jea Kwon, Min Gu Park, Seung Eun Lee, C. Justin Lee

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Circadian rhythm is defined as a 24-hour biological oscillation, which persists even without any external cues but also can be reentrained by various environmental cues. One of the widely accepted circadian rhythm behavioral experiment is measuring the wheel-running activity (WRA) of rodents. However, the price for commercially available WRA recording system is not easily affordable for researchers due to high-cost implementation of sensors for wheel rotation. Here, we developed a cost-effective and comprehensive system for circadian rhythm recording by measuring the house-keeping activities (HKA). We have monitored animal's HKA as electrical signal by simply connecting animal housing cage with a standard analog/digital converter: input to the metal lid and ground to the metal grid floor. We show that acquired electrical signals are combined activities of eating, drinking and natural locomotor behaviors which are well-known indicators of circadian rhythm. Post-processing of measured electrical signals enabled us to draw actogram, which verifies HKA to be reliable circadian rhythm indicator. To provide easy access of HKA recording system for researchers, we have developed user-friendly MATLAB-based software, Circa Analysis. This software provides functions for easy extraction of scalable "touch activity" from raw data files by automating seven steps of post-processing and drawing actograms with highly intuitive user-interface and various options. With our cost-effective HKA circadian rhythm recording system, we have estimated the cost of our system to be less than $150 per channel. We anticipate our system will benefit many researchers who would like to study circadian rhythm.

Original languageEnglish
Pages (from-to)65-75
Number of pages11
JournalExperimental Neurobiology
Issue number1
Publication statusPublished - 2018 Feb 1

Bibliographical note

Funding Information:
This study was supported by KIST Institutional Grant (2E26662 to C.J.L.) and Creative Research Initiative Program (2015R1A3A2066619). The authors declare no conflict of interest.

Publisher Copyright:
© Experimental Neurobiology 2018.


  • Circadian rhythm
  • Electrical Equipment and Supplies
  • Mice
  • Software

ASJC Scopus subject areas

  • Clinical Neurology
  • Cellular and Molecular Neuroscience


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