Key Takeaways:
- Brains preserved in archaeological findings are more common than previously believed, with over 4,400 instances identified.
- Preservation methods vary, with dehydration, freezing, and tanning contributing to the longevity of these brains.
- A quarter of preserved brains come from bodies lacking other soft tissues, emphasizing their exceptional nature.
- The unique 1-to-1 ratio of proteins to lipids in brains may contribute to their resilience against decay.
- Ongoing research aims to uncover the molecular mechanisms responsible for brain preservation.
Upon embarking on her investigation, Alexandra Morton-Hayward, a forensic anthropologist, stumbled upon a scholarly manuscript delineating a 2,500-year-old cerebral organ encased within a decapitated cranium. Referenced within this manuscript was yet another encephalic specimen. Encountering subsequent references, she found herself drawn into a trail of discoveries. The tally reached a dozen when she discerned a recurring theme in these manuscripts – the portrayal of brains as an extraordinary anomaly. Undeterred, she delved deeper.
Morton-Hayward, hailing from the esteemed University of Oxford, in conjunction with her peers, divulges on March 20 in Proceedings of the Royal Society B that naturally preserved brains, once thought to be exceedingly scarce, are, in fact, rather commonplace. Their compendium now boasts 4,400 instances of human brains preserved within the annals of archaeology, some tracing back nearly 12,000 years. Amongst these archival treasures are brains procured from Arctic explorers, sacrificial subjects of the Inca civilization, and soldiers fallen in the Spanish Civil War.
The rarity ascribed to these brains has, until now, dissuaded extensive inquiry. Morton-Hayward articulates, “If deemed invaluable artifacts, reluctance to dissect or probe them prevails.” A mere fraction of the compendium, less than 1 percent, has undergone scrutiny.
By correlating the geographical origins of these brains with historical climatic data, tantalizing insights into their preservation mechanisms emerge. Dehydration accounts for over a third of the specimens’ resilience; others owe their preservation to cryogenic conditions or tanning processes. Consequently, the consistency of the brains ranges from desiccated and fragile to gelatinous and akin to tofu.
Approximately a quarter of the encephalic specimens originate from cadavers devoid of any other form of soft tissue preservation. Morton-Hayward paints a vivid picture, stating, “Void of integumentary layers, renal organs, or musculature, a diminutive yet immaculate brain rests within the cranial confines.”
The enigma surrounding the persistence of brains amidst the deterioration of surrounding soft tissues remains unsolved. However, Morton-Hayward posits that the answer may lie within the unique chemical composition of the brain. Distinguishing itself with a protein-to-lipid ratio of 1-to-1, the brain contrasts starkly with other soft tissues characterized by higher carbohydrate content and disparate protein-to-lipid ratios. This distinctive ratio may play a pivotal role as metals such as iron infiltrate, catalyzing the fusion of proteins and lipids, thus bestowing durability upon the cerebral organ.
The research team now endeavors to employ state-of-the-art methodologies in elucidating the molecular intricacies underpinning brain preservation.
