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Neuroscientists today can preserve small volumes (<1mm³) of animal brain tissue immediately after death with incredible precision – the features and structure of every synapse within these volumes is well-protected down to the nanometer scale, using an inexpensive, room-temperature process of chemical fixation and plastic embedding, or "plastination." The image to the right is an example of plastination and local circuit tracing, occurring in leading neuroscience labs around the world today.  This work immediately raises the question:

“Can the standard chemical fixation and plastic embedding technique used for electron microscopic investigation of brain circuitry be adapted to preserve the synaptic connectivity of an entire human brain?”

This is a well-defined scientific question, and we now have the tools necessary to answer this question definitively.* This question is of great importance, for at least two reasons:

1. The new science of connectomics is gearing up to map the connectome, the full synaptic connectivity of an entire brain. The first major milestone for mammals will be a mouse brain and eventually, we will map an entire human brain. Development of whole brain chemical fixation and plastic embedding procedures seems an absolute prerequisite for such a scientific endeavor.
2. Since most neuroscientists today would agree that our unique memories are written into the brain at the level of synaptic connections, successful synaptic preservation of an entire brain after clinical death would very likely preserve the memories and identities of all individuals who might wish to do so, for themselves, for their loved ones, for science, or society. There are many who would desire the option to perfectly and inexpensively preserve their brains at the nanometer scale today, for the possibility that future science might be able to read their memories or restore their full identities, as desired.

With respect to the latter, millions of people have at some point considered the possibility of having themselves or their loved ones cryonically preserved (very low-temperature preservation and storage) in the hope that future medical technology might revive and cure them. Yet so far, only a few thousand have entered contracts to do so. Why? There are many potential reasons, yet one is a particularly tractable challenge to the scientific community. At present there is little evidence that the existing practice of cryonics preserves the precise wiring of our brain’s hundred billion neurons. Cryonics techniques have improved substantially in recent years, but the fundamental question remains:

“Does cryonics as practiced today adequately preserve the synaptic connectivity of an entire human brain?”

This is also a well-defined scientific question that can be answered today. This question is of great importance, particularly to terminally ill patients wishing to preserve their memories or identities today, for which cryonic preservation of unknown efficacy is presently their only alternative.

We at the Brain Preservation Foundation are dedicated to seeing that these questions are answered in a definitive scientific manner as soon as possible. To do so we have introduced the Brain Preservation Technology Prize – a prize that challenges connectomics researchers and cryonics practitioners alike to demonstrate their best whole brain preservation techniques on an animal whose brain is then sectioned at 1mm intervals and subjected to an independent comprehensive electron microscopic sampling survey looking for damage that would destroy synaptic connectivity. The Prize is designed to uncover the truth about the quality of today’s preservation techniques and to spur research into better techniques.

If you agree that these are important questions, and that resources should be devoted to definitively answering them, please consider lending your support. Would you like to join our Advisors group? Have a relevant advanced degree, technical or other experience? Contact us.

Footnotes

* In electron microscopy we can visualize preserved neural tissue down to about a 6 nanometer resolution. This allows us to directly see each neuron's synapses and dendrites, and all the larger molecular structures, including neurotransmitter vesicles in axon terminals, that form their connections. This level of neural structure is the most common definition of the connectome, how neurons connect to each other in a living brain.

Electron microscopy does not allow us to directly see things like individual membrane receptors and other even smaller molecules in the synapse, or the signal states (phosphorylation, methylation, etc.) of individual brain proteins. That level of structure is sometimes called the synaptome, and it remains an open question in neuroscience what features of the synaptome need to be preserved to preserve memory and identity. What we do know is that chemical fixation and cryonics both preserve the fats, proteins, sugars, and DNA in living neurons, and fix them effectively in place, and membrane receptors stay in their normal distributions as well, as verified by antibody probes. What we don't know yet is which of the very smallest molecules and cytoskeletal features in our neurons and glia are critical to memory and identity, and which signal states at the molecular level are also important.

Our current Brain Preservation Technology Prize is focused on the connectome. As neuroscience advances, we may learn that certain features of the synaptome must also be preserved. In that case, the Brain Preservation Foundation will offer additional synaptome-level Technology prizes. Bottom line: As neuroscience continues to advance, BPF will do our best to help science to determine whether reliable and affordable protocols can be found to preserve those brain structures that give rise to our memories and identities, according to our best evidence to date.