A conscious rethink: Why is brain tissue commonly preserved in the archaeological record? Commentary on: Petrone P, Pucci P, Niola M, et al. Heat-induced brain vitrification from the Vesuvius eruption in C.E. 79. N Engl J Med 2020;382:383-4. DOI: 10.1056/NEJMc1909867

Alexandra L Morton-Hayward,Tim Thompson,Jane E Thomas-Oates,Stephen Buckley,Axel Petzold,Abigail Ramsøe,Sonia O’Connor,Matthew J Collins

doi:10.1080/20548923.2020.1815398

Abstract

ABSTRACT Brain tissue is ubiquitous in the archaeological record. Multiple, independent studies report the finding of black, resinous or shiny brain tissue, and Petrone et al. [2020 “Heat-induced Brain Vitrification from the Vesuvius Eruption in C.E. 79.” N Engl J Med. 382: 383–384; doi:10.1056/NEJMc1909867] raise the intriguing prospect of a role for vitrification in the preservation of ancient biomolecules. However, Petrone et al. (2020) have not made their raw data available, and no detailed laboratory or analytical methodology is offered. Issues of contamination and misinterpretation hampered a decade of research in biomolecular archaeology, such that addressing these sources of bias and facilitating validation of specious findings has become both routine and of paramount importance in the discipline. We argue that the evidence they present does not support their conclusion of heat-induced vitrification of human brain tissue, and that future studies should share palaeoproteomic data in an open access repository to facilitate comparative analysis of the recovery of ancient proteins and patterns of their degradation.

Highlights

The rest of the heads buried there were completely dried up; one brain within the skull was discovered many years after burial, still soft and wet and free from decay, even when exposed to the light of day
As the old saying goes, you wait an age for a bus and two come along at once: Petrone et al.’s (2020) report on the recovery of “vitrified” human brain tissue from Roman Herculaneum is published only two weeks after Petzold et al.’s (2020) report on the recovery of an extensive brain proteome from a human brain from Iron Age Yorkshire
Given Petrone et al.’s assertion of “extreme radiant heat ... able to ignite body fat and vaporize soft tissues” (2020), we argue that the aforementioned, routine method should have been applied to this individual in order to ascertain whether a high temperature was achieved

Summary

Introduction

The rest of the heads buried there were completely dried up; one brain within the skull was discovered many years after burial, still soft and wet and free from decay, even when exposed to the light of day. Whenever these masses were dried and exposed to the air they seemed to be indestructible.” “The preserved structures strongly resembled human brains, they were hard in consistency and black in color” (Radanov et al 1992); “suitable temperature and ventilation apparently enabled rapid evaporation of intracellular brain fluid” (Radanov et al 1992) Black but not vitreous/resinous “black material” (Melton et al 2010)

Results

Conclusion