brain transplant

{{Short description|Theoretical medical procedure in which the brain is placed into a different body}}

File:Human brain in a vat.jpg brain in a jar.]]

A brain transplant or whole-body transplant is a procedure in which the brain of one organism is transplanted into the body of another organism. It is a procedure distinct from head transplantation, which involves transferring the entire head to a new body, as opposed to the brain only. Theoretically, a person with complete organ failure could be given a new and functional body while keeping their own personality, memories, and consciousness through such a procedure. Neurosurgeon Robert J. White has grafted the head of a monkey onto the headless body of another monkey. Electroencephalography (EEG) readings showed the brain was later functioning normally. Initially, it was thought to prove that the brain was an immunologically privileged organ, as the host's immune system did not attack it at first,{{Cite web | url=http://www.washingtoncitypaper.com/articles/45154/what-would-happen-in-a-brain-transplant-personalities-bodies-and/ |title = What Would Happen in a Brain Transplant? |first=Cecil |last=Adams |date=20 December 2013 |work=Washington City Paper}} but immune rejection caused the monkey to die after nine days.{{Cite web |url=http://www.dichotomistic.com/mind_readings_head_transplant.html |title=head transplants |first=John |last=McCrone |access-date=20 January 2015 |archive-url=https://web.archive.org/web/20150228155418/http://www.dichotomistic.com/mind_readings_head_transplant.html |archive-date=28 February 2015 |url-status=dead}}

Existing challenges

File:Peripheral nerve, cross section.jpg.]]

One of the most significant barriers to the procedure is the inability of nerve tissue to heal properly; scarred nerve tissue does not transmit signals well, which is why spinal cord injuries devastate muscle function and sensation.

Alternatively, a brain–computer interface can be used connecting the subject to their own body. A study{{cite journal|last1=Ethier|first1=C.|last2=Oby|first2=E. R.|last3=Bauman|first3=M. J.|last4=Miller|first4=L. E.|title=Restoration of grasp following paralysis through brain-controlled stimulation of muscles|journal=Nature|volume=485|issue=7398|date=April 2012|pages=368–371|issn=0028-0836|doi=10.1038/nature10987 |pmid=22522928 |pmc=3358575|bibcode=2012Natur.485..368E|url=http://211.144.68.84:9998/91keshi/Public/File/34/485-7398/pdf/nature10987.pdf|archive-url=https://web.archive.org/web/20130721070518/http://211.144.68.84:9998/91keshi/Public/File/34/485-7398/pdf/nature10987.pdf|archive-date=21 July 2013}} using a monkey as a subject shows that it is possible to directly use commands from the brain, bypass the spinal cord and enable hand function. An advantage is that this interface can be adjusted after the surgical interventions are done where nerves can not be reconnected without surgery.

Also, for the procedure to be practical, the age of the donated body must be close to that of the recipient brain: an adult brain cannot fit into a skull that has not reached its full growth, which occurs at age 9–12 years.

When organs are transplanted, aggressive transplant rejection by the host's immune system can occur. Because immune cells of the central nervous system (CNS) contribute to the maintenance of neurogenesis and spatial learning abilities in adulthood, the brain has been hypothesized to be an immunologically privileged (unrejectable) organ.{{cite journal|last1=Ziv|first1=Yaniv|last2=Ron|first2=Noga|last3=Butovsky|first3=Oleg|last4=Landa|first4=Gennady|last5=Sudai|first5=Einav|last6=Greenberg|first6=Nadav|last7=Cohen|first7=Hagit|last8=Kipnis|first8=Jonathan|last9=Schwartz|first9=Michal |display-authors=3 |title=Immune cells contribute to the maintenance of neurogenesis and spatial learning abilities in adulthood|journal=Nature Neuroscience|volume=9|issue=2|year=2006|pages=268–275|issn=1097-6256|doi=10.1038/nn1629 |pmid=16415867|s2cid=205430936}}{{cite magazine |first=Lou |last=Jacobson |url=http://linguafranca.mirror.theinfo.org/9708/fn.9708.html |title=A Mind is a Terrible Thing to Waste |magazine=Lingua Franca |date=August 1997}}Mike Darwin: [http://www.alcor.org/Library/html/ButWhatWillTheNeighborsThink.html But What Will The Neighbors Think? A Discourse On The History And Rationale Of Neurosuspension]. Cryonics, October 1988. However, immunorejection of a functional transplanted brain has been reported in monkeys.{{cite journal|last1=McCrone|first1=John|title=Monkey Business|journal=Lancet Neurology|date=Dec 2003|volume=2|issue=12|page=772|doi=10.1016/S1474-4422(03)00596-9|pmid=14636785|s2cid=5254407|url=http://www.dichotomistic.com/mind_readings_head_transplant.html|access-date=20 January 2015|quote=(As reproduced at author's personal webpage)|url-status=dead|archive-url=https://web.archive.org/web/20150228155418/http://www.dichotomistic.com/mind_readings_head_transplant.html|archive-date=28 February 2015|df=mdy-all|url-access=subscription}}

Partial brain transplant

In 1982, Dr. Dorothy T. Krieger, chief of endocrinology at Mount Sinai Medical Center in New York City, achieved success with a partial brain transplant in mice.{{cite news|url=https://www.nytimes.com/1982/06/18/us/transplant-success-reported-with-part-of-a-mouse-s-brain.html|title=Transplant Success Reported With Part of a Mouse's Brain |agency=Associated Press|date=18 June 1982|work=The New York Times|access-date=20 July 2010}}

In 1998, a team of surgeons from the University of Pittsburgh Medical Center attempted to transplant a group of brain cells to Alma Cerasini, who had suffered a severe stroke that caused the loss of mobility in her right limbs as well as had limited speech. The team hoped that the cells would correct the listed damage. She died later on.{{cite news|last=Vedantam |author-link=Shankar Vedantam|first=Shankar|title=Artificial Brain Cells Implanted In-Patient The Procedure Is The First of Its Kind. Doctors Hope Eventually To Treat Brain Disorders This Way. |date=2 July 1998 |url=http://articles.philly.com/1998-07-02/news/25737590_1_brain-cells-alma-cerasini-brain-disorders|work=The Philadelphia Inquirer |access-date=29 May 2013|archive-url=https://web.archive.org/web/20160418185950/http://articles.philly.com/1998-07-02/news/25737590_1_brain-cells-alma-cerasini-brain-disorders|archive-date=18 April 2016|url-status=dead}}

References

External links

[https://www.bennun.biz/interviews/drwhite.html Dr Robert White], profile by David Bennun in The Sunday Telegraph Magazine, 2000

Category:Neurosurgery

Category:Organ transplantation

brain transplant

Existing challenges

Partial brain transplant

See also

References

External links