Early Supraspinal Influences on Human Embryonic Posture

Knowledge of embryonic body posture as a reflection of neurodevelopment is limited. Here, we investigate embryonic body posture, preference, symmetry, and lateralization during periods of rest using virtual reality (VR) and four-dimensional (4D) ultrasound techniques to enhance our knowledge of neurodevelopment. It is hypothesized that lateralization and asymmetry in embryonic posture are absent. Embryos from low-risk pregnancies at 9 weeks gestational age (GA) were analyzed using a 30-min 4D ultrasound and VR techniques. In the middle of an embryonic resting period, the total body posture was determined by combining joint positions. Interindividual and intraindividual postures were analyzed over time to identify posture preferences, asymmetry, and lateralization. Sixteen embryos (N = 210 middle frames out of 210 resting periods) displayed 27 different embryonic body postures. Interindividual and intraindividual variations in postures were seen. Asymmetry was noted in upper extremities, whereas lateralization of the head and spine was observed in nine embryos. Intraindividual and interindividual variation in embryonic posture at 9 weeks' GA is seen, suggesting the presence of supraspinal influences on body posture this early. Future interdisciplinary longitudinal studies on embryonic posture may provide further insights into embryonic central nervous system development, contributing to our understanding of embryonic health.