Establishing the pig as a translational animal model for neurodevelopment.

Background: Within the last few decades, the domestic pig has emerged as an advantageous biomedical animal model due to a vast number of similarities in realms of development and neuroanatomical features. Even so, a major challenge remains in how to translate time between the pig and human. Previously, researchers have developed a Translating Mammalian Time model that estimates the timing of 95 neurodevelopmental events across 9 mammalian species. By identifying the timing of these various events, one can include an additional animal into the model and assign a unique species score to predict the post-conception day (PCD) that other events will occur. Objective: Our objective was to conduct a comprehensive literature review of pig neurodevelopmental events to enable chronological comparison to other mammalian species, including humans. Methods: A total of 30 neurodevelopmental events with corresponding PCDs were identified, that were then used to optimize the pig's species score using grid search and gradient descent approaches. Results and Conclusion: Across both methods, the same species score of 2.157 was derived with a residual sum of squares of 4260.46. This species score places the domestic pig between the cat (1.808) and the macaque (2.255), thereby reinforcing the translational power of the pig comparable to non-human primates.