Automated Estimation of Mouse Social Behaviors Based on a Hidden Markov Model.

Recent innovations in sensing and Information and Communication Technology (ICT) have enabled researchers in animal behavior to collect an enormous amount of data. Consequently, the development of an automated system to substitute for some of the observations and analyses that are performed currently by expert researchers is becoming a crucial issue so that the vast amount of accumulated data can be processed efficiently. For this purpose, we introduce a process for the automated classification of the social interactive status of two mice in a square field on the basis of a Hidden Markov model (HMM). We developed two models: one for the classification of two states, namely, indifference and interaction, and the other for three states, namely, indifference, sniffing, and following. The HMM was trained with data from 50 pairs of mice as provided by expert human observers. We measured the performance of the HMM by determining its rate of concordance with human observation. We found that sniffing behavior was segmented well by the HMM; however, following behavior was not segmented well by the HMM in terms of percentage concordance. We also developed software called DuoMouse, an automated system for the classification of social interactive behavior of mice, that was based on the HMM. Finally, we compared two implementations of the HMM that were based on a histogram and a Gaussian mixture model.

[The First Successful Application of a Mask with a Left Side Slit for Passing the Trunk of an Endoscope In Situ and Enabling Respiratory Support during Sedation for Upper Gastrointestinal Endoscopy].

Sedation in patients during gastrointestinal (GI) endoscopy involves the risk of respiratory depression. Ventilation support with a conventional face mask without removing an endoscope is impossible. We devised a ventilation mask with a slit and membranous valve on the left side wall and the circular upper end enabling to pass the trunk of an endoscope in situ, based on an idea published in the Japanese Journal of Anesthesia "Masui" 2013; 62: 105-8. An 82-year-old woman was scheduled for GI endoscopy for severe abdominal pain. An endoscope was inserted into her GI tract through the mouth after midazolam 1.5 mg i.v. Soon after the examination began, she developed respiratory depression, and her SpO2 gradually decreased to 84%, despite oxygen insufflated around the nose and mouth. The new slit mask was applied without removing the endoscope, and respiratory support was started by bag-valve method. Her SpO2 recovered and remained above 95% thereafter as the endoscopic examination continued. The side slit mask offers important advantages allowing its application in situ after an endoscope being inserted and by enabling positive pressure ventilation without interrupting the endoscopic procedure.

A male-specific QTL for social interaction behavior in mice mapped with automated pattern detection by a hidden Markov model incorporated into newly developed freeware.

BACKGROUND: Owing to their complex nature, social interaction tests normally require the observation of video data by a human researcher, and thus are difficult to use in large-scale studies. We previously established a statistical method, a hidden Markov model (HMM), which enables the differentiation of two social states ("interaction" and "indifference"), and three social states ("sniffing", "following", and "indifference"), automatically in silico. NEW METHOD: Here, we developed freeware called DuoMouse for the rapid evaluation of social interaction behavior. This software incorporates five steps: (1) settings, (2) video recording, (3) tracking from the video data, (4) HMM analysis, and (5) visualization of the results. RESULTS: Using DuoMouse, we mapped a genetic locus related to social interaction. We previously reported that a consomic strain, B6-Chr6C(MSM), with its chromosome 6 substituted for one from MSM/Ms, showed more social interaction than C57BL/6 (B6). We made four subconsomic strains, C3, C5, C6, and C7, each of which has a shorter segment of chromosome 6 derived from B6-Chr6C, and conducted social interaction tests on these strains. DuoMouse indicated that C6, but not C3, C5, and C7, showed higher interaction, sniffing, and following than B6, specifically in males. COMPARISON WITH EXISTING METHOD: The data obtained by human observation showed high concordance to those from DuoMouse. The results indicated that the MSM-derived chromosomal region present in C6-but not in C3, C5, and C7-associated with increased social behavior. CONCLUSIONS: This method to analyze social interaction will aid primary screening for difference in social behavior in mice.