Suspicious minds: a multi-omics approach to neural tissues in the archaeological record, and insights from molecular taphonomy
University of Oxford
As one of the first organs to decompose post-mortem, brains are far more numerous than they should be in the archaeological record. >1800 have been reported by generations of baffled archaeologists in the last 400 years; yet deep-time brain preservation is stubbornly described as a ‘unique’ or ‘exceptionally rare’ phenomenon, and remains little-investigated.
One of the foremost areas of current neuropathological research is the time- dependent change in the amino acid chemistry of the brain.
As we age, spontaneous protein modifications promote molecular misfolding, polymerisation and aggregation; but tissue deposition of these neurotoxic fibrils need not necessarily end with the cessation of life. Might the formation of organically insoluble, non-hydrolysable plaques, so devastating in a plethora of dementias, perversely act to preserve the brain after death, stabilising biomolecules during long-term diagenesis?
Today, low socioeconomic status is recognised as a key risk factor for accelerated brain ageing. One of the most infamous sites of impoverishment in the past is that hallmark of the long 19th C. in Industrial Europe: the Victorian workhouse, which housed the elderly as often as the penniless. A former workhouse in south-west Britain has to-date yielded the well-preserved brains of >300 former inmates, which pilot analyses (proteins, lipids, metabolites and aDNA) demonstrate is an exceptionally rich reservoir of biomolecular information. Most particularly, patterns of protein modification suggest that, not only do preserved brains shed light on health and disease in the long-dead, but probing the utmost extent of neural plaque deposition in the archaeological record might also illuminate the clinical trajectory of living tissues in the aged.
This multi-omics approach to the study of preserved neural tissues is the first of its kind, unravelling the means by which the brain persists when other organs perish.