Nectome and Biostasis Technologies propose evaluating brain preservation by how well it preserves personal identity

Nectome and Biostasis Technologies propose evaluating brain preservation by how well it preserves personal identity

On July 31, Jessica Radley of Nectome and Aschwin de Wolf of Biostasis Technologies published an essay on cryopreservation and chemical brain fixation. They propose comparing procedures according to how much of an individual's neural structure remains available for future recovery.

Cryopreservation replaces some of the water in the tissue with a cryoprotectant and cools the brain. Chemical fixation introduces aldehydes, which crosslink proteins, stop tissue degradation, and preserve tissue structure. Each procedure leaves different changes in the tissue. The authors therefore argue that the name of a method alone says little about the quality of preservation.

In the essay “Biostasis Pluralism”, Radley and de Wolf propose asking whether the neuroanatomical basis of a particular person has been preserved. They include DNA, cell type markers, connections between cells, and, most importantly, synapses, which are the contact points between neurons. The authors associate this network with the memories, skills, and habits that distinguish one person from another.

The authors consider three possible routes: biological revival, brain scanning followed by reconstruction of the person, and repair at the nanoscale. In their model, scanning and repair would require future technology to distinguish an individual's structure from damage caused by the preservation procedure. The less that technology must reconstruct from a general model of the brain, the more of that specific person remains preserved in the tissue.

A single successful image of synapses shows only the selected area. The authors propose first creating a large-scale map of the entire brain and then using electron microscopy to examine regions distributed throughout it. The quality of a procedure should be assessed not from one sample, but from the distribution of preservation across the entire brain. The Brain Preservation Foundation already uses this approach to evaluate aldehyde-stabilized cryopreservation.

Information about where the preservation solution reached, where tissue structure remained intact, and which parts of the brain can be read makes it possible to compare procedures by a single criterion: the information preserved about a particular brain, rather than the proposed method of future recovery.