Evidence for Long Term Memory to Survive Vitrification in Nematode Worms
Cryonics is the low-temperature preservation of the deceased in order to grant them a chance at a renewed life when technologies for restoration are developed. One of the big outstanding questions is the degree to which cryopreservation successfully preserves the fine structure of the brain and thus the data of the mind. The fact that cold water drowning victims can live again after an hour or more of brain death tells us that memory is encoded in physical structures, with the current consensus suggesting it is located in synaptic connections between neurons. Scanning technologies have been used to show that cryopreservation via vitrification of cryoprotectant-infused tissue does indeed preserve the fine structure of brain cell connections, but there is always the need for more and better proof. At the present time studies involving restoration of vitrified individuals must be carried out in lower animals, as researchers are still far from the point at which they can safely restore vitrified mammals:
Can memory be retained after cryopreservation? Our research has attempted to answer this long-standing question by using the nematode worm Caenorhabditis elegans (C. elegans), a well-known model organism for biological research that has generated revolutionary findings but has not been tested for memory retention after cryopreservation. Our study's goal was to test C. elegans' memory recall after vitrification and reviving.
Using a method of sensory imprinting in the young C. elegans we established that learning acquired through olfactory cues shapes the animal's behavior and the learning is retained at the adult stage after vitrification. Our research method included olfactory imprinting with the chemical benzaldehyde (C6H5CHO) for phase-sense olfactory imprinting at larval stage 1, the fast cooling SafeSpeed method for vitrification at larval stage 2, reviving, and a chemotaxis assay for testing memory retention of learning at the adult stage. Our results in testing memory retention after cryopreservation show that the mechanisms that regulate the odorant imprinting (a form of long-term memory) in C. elegans have not been modified by the process of vitrification or by slow freezing.
The paper is now available for download: http://online.liebertpub.com/doi/pdf/10.1089/rej.2014.1636