Development of the equine brain motor system.

This research studied the structure development of the horse brain during the critical period when coordinated movement begins, using various histological methods. The results indicate that substantial changes in the motor system, including increased protein synthesis and complete myelination of motor tracts, occur in synchrony with the onset of coordinated movement.

Study Methodology

• The study observed equine brains at various stages of development, from 14 days pre-birth to adulthood. These brains were preserved in formaldehyde and enveloped in paraffin for further examination.
• Detailed coronal sections of the brains were prepared using a special microtome, a tool used for cutting extremely thin slices of material. These slices were then stained using Nissl’s cresyl violet and Haidenhain’s iron-haematoxylin, two histological stains used to highlight specific features of tissue under microscopic examination.
• The microscopic images of these stained sections were digitized for further computer-aided image analysis, a technique that involves converting images into numerical data for quantitative assessment.

Study Findings

• The gross morphology (overall structural features) of the brains and the image analysis of the histological preparations did not show a substantial increase in brain size and mass during the perinatal period (around the time of birth).
• However, the amount of the Nissl substance, which is a marker of protein synthesis in neurons, and myelin, a type of fat that insulates nerve fibers and facilitates effective nerve impulse transmission, increased rapidly till the 45th postnatal day. This was followed by a relative decrease of both until adulthood.
• Interestingly, despite the reduction in Nissl substance and myelin, the brain size and mass doubled from postnatal day 45 till adulthood.

Conclusion

• Based on the findings, the study concluded that during the maturation of the equine brain, significant changes occur in the brain’s motor system. Specifically, this involves an increase in protein synthesis and complete myelination of motor tracts during the critical period of the onset of coordinated movement.
• This research offers valuable insight into the development of motor skills in horses, with potential implications for understanding similar processes in other mammals, including humans. Furthermore, understanding these brain developmental stages may aid in diagnosing and treating various neurological conditions in equines and other mammals.