A pig’s brain was frozen with its cellular activity fixed in place and with minimal damage. It is believed that the same could be done with the brains of terminally ill humans, so that their minds can be rebuilt and they can “continue living”.
One entire mammalian brain has been preserved successfully using a new technique revealed in a study earlier this month in bioRxiv.
The goal is to preserve all neural information deemed necessary for one day rebuild the mind of the person to whom it once belonged.
“What we are offering is that their body and brain are maintained, essentially indefinitely, in the hope that someday in the future it will be possible to read the information in the brain and reconstruct the person… to allow them, in practice, to continue with their life”, explain the research leader Borys Wróbelfrom Nectome in Portland, Oregon, a research firm focused on memory preservation, to .
As the same magazine points out, when it comes to preserving the brain’s tiny architecture, time is critical. Within minutes after the blood stops circulating, enzymes break down neurons and cells begin to digest themselves.
To overcome this problem, the team developed and defends a technique compatible with assisted death, in which a terminally ill person chooses the moment of their death. The idea, by intervening immediately, scientists have the best chance of preserving the brain in a state that closely reflects a living condition.
The contours of the mysterious technique
The team tested the process in pigs, which have brain and cardiovascular anatomy comparable to that of people.
As New Scientist details, first, a cannula was inserted into the heart about 10 minutes after cardiac arrest, before removing the blood and introducing preservation solutions into the brain. These fluids contain chemical aldehydes, which create molecular bridges between cells, essentially locking cellular activity in place.
Then, cryoprotectants were introduced, which replace the water within the tissue, preventing the formation of ice crystals during cooling, which would otherwise damage the cells. Right away, the brain has been cooled to around -32°C, at which point it can be preserved for hundreds of years.
To assess how well this worked, the team took samples from the outermost layer of the brain and examined them using microscopy.
The first attempts, in which perfusion began about 18 minutes after death, showed clear signs of cell damage.
After reducing this delay to just under 14 minutes, the tissue showed excellent preservation of tiny structures, including neurons, synapses and the molecules that make them up.
The team mentions to New Scientist that, in theory, they could use this protocol “to reconstruct the three-dimensional structure of neurons and the connections between them.”
This is known as the connectomeand it is hoped that by mapping it it can help understand how the brain produces our thoughts, feelings and perceptions. So far, scientists have only been able to map a small part of the mouse brain in this way.
Questionable method
“Even a perfect copy of my mind would still be a different entity, although I recognize that some people see this as a potential path to a kind of ‘virtual immortality’,” the skeptic told the same magazine. João Pedro de Magalhãesfrom the University of Birmingham, in the United Kingdom
Regardless of hypothetical futures, the work raises deep ethical and philosophical questions about our definition of death.
