Could our brains last forever? Neural grafting and cryonics

By Daniel Earnshaw, Assistant Psychologist (Research) at Brainkind

During this summer holiday season, we found ourselves thinking about the future. In particular, the future of rehabilitation, and some of the technological advancements that may revolutionise our practice, and outcomes for patients.

This edition of Research Digest explores neural grafting, cryonics and brain transplants, and asks what their potential is to help us live longer, more healthily, recover from injury or illness, or even live forever! We also delve into the ethics of such procedures and whether we, as a society, are ready to accept these advances in technology.

 

Neural grafting

The most feasible of the innovations that we are considering is nerve transplantation or neural grafting. This is the process of transplanting a single nerve cell or multiple nerve cells into a part of the nervous system or the brain. Our brains have limited ability to repair damaged nerve cells, which is why transplanting nerves may have potential to treat brain injuries [1, 2]. Neural grafting for the purpose of treating brain injuries has so far only been tested on animals with some positive outcomes [3, 4]. However, neural grafting has been used in humans to repair peripheral nerve defects [5] and has been used in the brain to treat Parkinson’s disease [6]. The survival rates for neural grafting to treat Parkinson’s disease are currently low, but they have increased over time, with the longest surviving case reported to live 24-years post-surgery [6]. The main challenges are related to the body’s immune response and how well the transplanted cells are able to survive, grow, and migrate after being implanted [7].

 

Cryonics and cryopreservation

Cryogenics is a science studying the production and effects of very low temperatures and its applications in areas such as food preservation and engineering [8]. In medicine it is used to preserve some tissue such as sperm and eggs [9]. Some companies have invested quite a lot of money into using this technology to preserve human tissue, usually either an entire body or just a head, with the goal of future revival and restoration to a healthy state [10]. When cold temperatures are applied in this way, it is known as “cryonics”. Currently, there are more than 500 people frozen worldwide, with many more on waiting lists [11]. However, there are issues with cryonics. Firstly, the process of freezing can damage the cells in the human body, including the brain. This means that we cannot currently ensure that successful revival is possible [12]. However, some researchers such as Best [10] have argued that similarly to other historical advancements, such as nuclear fission and the moon landing, it may be worth the risk of trying!

 

Brain transplants

Transplanting a brain or head from one body to another is another outlandish innovation which may be worth our attention. Attempts to achieve this have been carried out on animals from as early as 1908, with the first successful head transplantation of a dog by Carrel and Guthrie. However, this experiment involved attaching the front of a dog’s torso onto another dog’s neck, essentially conjoining the two dogs [13], which isn’t what many of us have in mind when we think of a head transplant. A full head transplant was first achieved by White in 1970 on four rhesus monkeys, with one surviving 36 hours post-surgery. Even then, these, monkeys were not physically mobile post-operation and were limited to chewing, swallowing, eye tracking, and biting [13, 14]. To date, no successful human head or brain transplantation has been achieved, and this may be far off in the horizon due to a number of challenges. One of the tallest hurdles to overcome is disconnecting and reconnecting a head or brain to a new body, particularly in severing and reconnecting the spinal cord [13]. Similarly to what happens with most other organ transplants, patients would need to take immunosuppressant medication in order to keep their immune system from rejecting the new head or brain [13]. Finally, finding a willing but healthy donor may never be possible!

 

Ethical considerations

Neural grafting currently requires a donation of embryonic stem cells due to their ability to self-renew, adapt, and change the structure of surrounding cells. Using embryos in stem cell research has a history of ethical and legal issues, especially regarding abortion [15]. Donating an embryo is completely voluntary in the UK [16] but some may not feel comfortable donating and others may not feel comfortable receiving an embryo donation for the purpose of neural grafting, as the embryo is destroyed in the process. An alternative to embryonic stem cells may be adult (somatic) stem cells. These can be transplanted autologously, which means the patient’s own stem cells are used, but the ability of these cells to change and adapt their structure is limited to the organ from which they were donated. More clinical trials are needed to determine how effective adult stem cells are in comparison to their embryonic counterparts [17], but their use may be less ethically controversial than that of embryonic stem cells.

Cryonics also raises ethical, moral, and legal issues. Death is seen as natural in most cultures and those who believe in an afterlife may believe that death is a necessary part of human existence. Thus, some religious communities are met with a question: ‘if there is an afterlife, have they already passed onto there by the time of freezing?’ And what are the spiritual implications of resurrecting someone after they have passed? [18]. Additionally, German and Tretter have suggested that humans may be instinctively averse to anything related to corpses due to connotations to pathogens and disease and therefore may find cryonics to be unpleasant and disgusting [19]. Theological dilemmas and societal attitudes such as these may have an impact on whether people volunteer for, or even support, research into this area. One issue is that of equality, cryonics is currently exclusive to those who can afford it. For example, one of the largest cryonic companies in the US, charges between $80,000 to $220,000 on top of monthly membership fees [20]. Thus, both technology and our societal values and institutions may have a long way to go before cryopreservation becomes mainstream (if it ever does).

There is endless potential for debate over the legality and ethics of brain transplants and most of all what they mean in terms of personal identity. Although having some neural cells grafted into our nervous system may not change who we are, it may be different when we consider transplanting an entirely new brain or body. Whose identity persists after such a transplant? How much does the body play a role in our sense of self, personality, and emotion? And how should this new person be treated legally and socially? These questions are all object of heated philosophical debate [21]. Like cryonics, it may be that not only technology but also our society and culture may need to go through some major changes in order for brain transplants to become accepted as a credible medical procedure.

 

In conclusion

These innovations may currently seem far off in the horizon or even impossible but only time will tell how useful they will be and how ready we will be to use them. At present, their potential application in brain injury rehabilitation seems limited, with neural grafting appearing to be the most (or only) promising one out of the three technologies mentioned. But even this may still require many animal and human clinical trials before it can be approved for mainstream medical use.

While this month’s Research Digest explored cutting-edge scientific areas, ultimately there are very few truly novel ideas. Like many others in science, some of the topics covered here have also been depicted in the arts. Take the film ‘Poor Things’ (2023), for example…

 

References

[1] Sun, D. (2016). The potential of neural transplantation for brain repair and regeneration following traumatic brain injury. Neural Regeneration Research, 11(1), 18.

[2] Huang, L., & Zhang, L. (2019). Neural stem cell therapies and hypoxic-ischemic brain injury. Progress in Neurobiology, 173, 1–17.

[3] Lee, J.-Y., Acosta, S., Tuazon, J. P., Xu, K., Nguyen, H., Lippert, T., Liska, M. G., Semechkin, A., Garitaonandia, I., Gonzalez, R., Kern, R., & Borlongan, C. V. (2019). Human parthenogenetic neural stem cell grafts promote multiple regenerative processes in a traumatic brain injury model. Theranostics, 9(4), 1029–1046.

[4] Liu, S., Tian, H., Niu, Y., Yu, C., Xie, L., Jin, Z., Niu, W., Ren, J., Fu, L., & Yao, Z. (2022). Combined cell grafting and VPA administration facilitates neural repair through axonal regeneration and synaptogenesis in traumatic brain injury. Acta Biochimica et Biophysica Sinica, 54(9), 1289.

[5] Tada, K., Nakada, M., Matsuta, M., Yamauchi, D., Ikeda, K., & Tsuchiya, H. (2020). Long-term outcomes of donor site morbidity after sural nerve graft harvesting. Journal of Hand Surgery Global Online, 2(2), 74–76.

[6] Li, J.-Y., & Li, W. (2021). Postmortem studies of fetal grafts in Parkinson’s disease: what lessons have we learned? Frontiers in Cell and Developmental Biology, 9.

[7] Henriques, D., Moreira, R., Schwamborn, J., Pereira de Almeida, L., & Mendonça, L. S. (2019). Successes and hurdles in stem cells application and production for brain transplantation. Frontiers in Neuroscience, 13.

[8] Tomorrow.bio. (n.d.) Where Do We Already Use Cryogenics? Retrieved August 14, 2025, from https://www.tomorrow.bio/post/how-is-cryogenics-used-today

[9] University Hospitals Coventry and Warwickshire. (n.d.). Cryopreservation (embryo, egg and sperm freezing). Retrieved August 22, 2025, from https://www.uhcw.nhs.uk/ivf/treatments/cryopreservation/

[10] Best, B. P. (2008). Scientific justification of cryonics practice. Rejuvenation Research, 11(2), 493–503.

[11] Mihalicz, J. (2024, June 1). Cryogenics Statistics and Facts: 2024. Vitality Pro. https://vitality-pro.com/statistics-trends/cryogenics-worldwide/

[12] McKenzie, A. T., Thorn, E. L., Nnadi, O., Wróbel, B., Kendziorra, E., Farrell, K., & Crary, J. F. (2024). Cryopreservation of brain cell structure: a review. Free Neuropathology, 5, 35.

[13] Lamba, N., Holsgrove, D., & Broekman, M. L. (2016). The history of head transplantation: a review. Acta Neurochirurgica, 158(12), 2239–2247.

[14] Engebretson, K. (n.d.) The Seminal and Sometimes Weird Science of Dr. Robert White. University of St. Thomas. Retrieved August 13, 2025, from https://news.stthomas.edu/publication-article/the-seminal-and-sometimes-weird-science-of-dr-robert-white/#:~:text=In%201970%2C%20White%2C%20with%20his,head%20onto%20another%20monkey%27s%20body.

[15] Charitos, I. A., Ballini, A., Cantore, S., Boccellino, M., Di Domenico, M., Borsani, E., Nocini, R., Di Cosola, M., Santacroce, L., & Bottalico, L. (2021). Stem cells: a historical review about biological, religious, and ethical issues. Stem Cells International, 2021(1), 9978837.

[16] Human Tissue Authority. (2021, June 17). Donating your tissue for research FAQs. https://www.hta.gov.uk/guidance-public/donating-your-tissue-research/donating-your-tissue-research-faqs

[17] Mariano, E. D. (2015). Adult stem cells in neural repair: Current options, limitations and perspectives. World Journal of Stem Cells, 7(2), 477. https://doi.org/10.4252/wjsc.v7.i2.477

[18] Mercer, C. (2017). Resurrection of the body and cryonics. Religions, 8(5), 96. https://doi.org/10.3390/rel8050096

[19] German, A., & Tretter, M. (2025). Brain preservation and cryonics through the lens of moral psychology. Neuroethics, 18(1).

[20] Alcor Life Extension Foundation. (n.d.) Required Costs and Cryopreservation Funding Minimums. Retrieved August 14, 2025, from https://www.alcor.org/library/required-costs-and-cryopreservation-funding-minimums/

[21] Pascalev, A., Pascalev, M., & Giordano, J. (2015). Head transplants, personal identity and neuroethics. Neuroethics, 9(1), 15–22.