3-D motion capture for long-term tracking of spontaneous locomotor behaviors and circadian sleep/wake rhythms in mouse.

BACKGROUND: Locomotor activity provides an index of an animal's behavioral state. Here, we report a reliable and cost-effective method that allows long-term (days to months) simultaneous tracking of locomotion in mouse cohorts (here consisting of 24 animals). NEW METHOD: The technique is based on a motion capture system used mainly for human movement study. A reflective marker was placed on the head of each mouse using a surgical procedure and labeled animals were returned to their individual home cages. Camera-recorded data of marker displacement resulting from locomotor movements were then analyzed with custom built software. To avoid any data loss, data files were saved every hour and automatically concatenated. Long-term recordings (up to 3 months) with high spatial (<1mm) and temporal (up to 100Hz) resolution of animal movements were obtained. RESULTS: The system was validated by analyzing the spontaneous activity of mice from post-natal day 30-90. Daily motor activity increased up to 70days in correspondence with maturational changes in locomotor performance. The recorded actigrams also permitted analysis of circadian and ultradian rhythms in cohort sleep/wake behavior. COMPARISON WITH EXISTING METHOD(S): In contrast to traditional session-based experimental approaches, our technique allows locomotor activity to be recorded with minimal experimenter manipulation, thereby minimizing animal stress. CONCLUSIONS: Our method enables the continuous long-term (up to several months) monitoring of tens of animals, generating manageable amounts of data at minimal costs without requiring individual dedicated devices. The actigraphic data collected allows circadian and ultradian analysis of sleep/wake behaviors to be performed.

An examination of camptocormia assessment by dynamic quantification of sagittal posture.

OBJECTIVE: Camptocormia is a disabling pathology of the axial system that debilitates patients in their daily life. To date, there have been no studies evaluating the impact of camptocormia on walking performance. This study presents a new method for assessing sagittal posture under walking conditions in patients with camptocormia. DESIGN: The severity of camptocormia was evaluated by measuring sagittal inclination, represented indirectly by the horizontal distance between the C7 and S1 markers (C7 sagittal arrow; C7-SAR). Sagittal inclination was measured under various behavioural conditions using clinical, radiological and kinematic approaches. PATIENTS: Forty-three patients were included in the study (17 with Parkinson's disease and 26 with idiopathic camptocormia). RESULTS: Under static conditions, C7-SAR could be assessed using different methods. During walking, there was a dramatic increase in C7-SAR values. Correlation analysis revealed a relationship between functional impairment and dynamic C7-SAR values, but not with radiological C7-SAR values. PATIENTS with Parkinson's disease behaved differently from idiopathic patients, suggesting the involvement of different underlying physiopathological mechanisms. CONCLUSION: Monitoring sagittal inclination during walking is more accurate than radiological measurements to determinine the detrimental effects of camptocormia and its consequences for quality of life.