SAP-Detector: Automated detection of stretch-attend posture through the detection of the change point of body length in mice

초록

The stretch-attend posture (SAP) is a behavior observed in rodents, particularly mice and rats, characterized by a distinct stretching movement followed by an attentive pause. This posture typically occurs in response to the detection of potential threats. SAP proves to be more useful in detecting fear responses towards specific stimuli, such as social subjects in social fear studies. However, a standardized protocol for quantifying SAP is currently lacking, and existing methods are subject to some degree of subjectivity and prone to errors. To address this gap, we have developed SAP-Detector, an open-source application designed to accurately measure SAP by detecting changes in body length using the coordinates of the mice's body parts. SAP-Detector segments behavior video data into short segments with consistent body lengths, subsequently identifying segments with prolonged body length and reduced movement speed as indicative of SAP. We evaluated SAP-Detector's performance using videos of male C57BL/6 mice in an open field box interacting with social subjects following social fear conditioning. Our results demonstrate that SAP-Detector achieves comparable accuracy and speed in detecting SAP compared to previous methods and human observers. The availability of SAP-Detector as a freely-accessible tool offers biologists a consistent means of measuring SAP, thereby enhancing the reliability of behavioral assessments. This advancement holds promise for improving the standardization and efficiency of SAP quantification in rodent studies