The Small Mammalian Brain Preservation Prize was awarded after the determination that the protocol developed by McIntyre, termed Aldehyde-Stabilized Cryopreservation, was able to preserve an entire rabbit brain with well-preserved ultrastructure, including cell membranes, synapses, and intracellular structures such as synaptic vesicles. See the BPF website for the full details of the protocol. The judges for the prize were Kenneth Hayworth, Brain Preservation Foundation President and neuroscientist at the Howard Hughes Medical Institute, and Princeton neuroscientist Sebastian Seung.
This is a milestone in the development of brain preservation techniques: it is the first time that the preservation of the connectome has been demonstrated in a whole brain (prior to this only small parts of brains have been preserved to this level of detail). Current models of the brain suggest that the connectome contains all the information necessary for personal identity (i.e. memory and personality). This technique is not the same as conventional cryonics (rapidly freezing the brain) which has never demonstrated preservation of the ultrastructure of the brain. Thus the winning of this prize represents a significant advance in the methods available for large scale studies of the connectome and could lead to procedures that preserve a complete human brain. Winning the award also required that the procedure be published in a peer reviewed scientific publication. McIntyre satisfied this requirement and published the protocol in the Journal of Cryobiology.
Proponents of cryonics have long sought a technique that could put terminal patients into long term stasis, the goal being a form of medical time travel in which patients are stabilized against decay with the hope of being biologically revived and cured by future technologies. Despite decades of research, this goal of reversible cryopreservation remains far out of reach – too much damage occurs during the cryopreservation itself. This has led a new generation of researchers to focus on a more achievable and demonstrable goal –preservation of brain structure only.
Specifically, preservation of the delicate pattern of synaptic connections (the “connectome”) which neuroscience contends encodes a person’s memory and identity. Instead of biological revival, these new researchers often envision a future “synthetic revival” comprising nanometer scale scanning of the preserved brain to serve as the basis for mind uploading. This shift in focus toward “synthetic” revival has completely transformed the cryonic debate, opening up new avenues of research and bringing it squarely within the purview of today’s scientific investigation. Hundreds of neuroscience papers have detailed how memory and personality are encoded structurally in synaptic connections, and recent advances in connectome imaging and brain simulation can be seen as a preview of the synthetic revival technologies to come.
Until now, the crucial unanswered questions were “How well does cryonics preserve the brain’s connectome?” and “Are there alternatives/modifications to cryonics that might preserve the connectome better and in a manner that could be demonstrated today?” The Brain Preservation Prize was put forward in 2010 to spur research that could definitively answer these questions. Now, five years later, these questions have been answered: Traditional cryonics procedures were not able to demonstrate (to the BPF’s satisfaction) preservation of the connectome, but the newly invented “Aldehyde Stabilized Cryopreservation” technique was.
The key breakthrough was the rapid perfusion of a deadly chemical fixative (glutaraldehyde) through the brain’s vascular system, instantly stopping metabolic decay and fixing all proteins in place by covalent crosslinks. This stabilized the tissue and vasculature so that cryoprotectant could be perfused at an optimal temperature and rate. The result was an intact rabbit brain filled with such a high concentration of cryoprotectants that it could be stored as a solid “vitrified” block at a temperature of 135 degrees Celsius. The inclusion of a deadly fixative has already been criticized by some in the traditional cryonics community, but according to the scientific publication its use was crucial to the results obtained. This result directly answers what has for decades been the main skeptical and scientific criticism against cryonics –that it does not provably preserve the delicate synaptic circuitry of the brain. As such, this research sets the stage for renewed interest within the scientific community, and offers a potential challenge to medical researchers to develop a human surgical procedure based on these successful animal experiments.
The Brain Preservation Foundation plans to continue to promote the idea that brain preservation following legal death, by using scientifically validated techniques, is a reasonable choice for consenting individuals to make. Focus now shifts to the final Large Mammal phase of the contest which requires an intact pig brain to be preserved with similar fidelity in a manner that could be directly adapted to terminal patients in a hospital setting. The 21st Century Medicine team has recently submitted to the BPF such a preserved pig brain for official evaluation. Lead researcher Robert McIntyre has started Nectome to further develop this method.
Dr. Michael Cerullo is a psychiatrist and neuroscientist. His main interests are the scientific study of consciousness and personal identity and what these subjects tell us about the feasibility of whole brain emulation. He is currently a Fellow at the Brain Preservation Foundation.
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