Brain Transplantation: Scientific Feasibility, Neurobiological Barriers, Ethical Constraints, and a Responsible Research Roadmap

Brain transplantation occupies an unusual boundary between transplant surgery, 
neurocritical care, spinal-cord repair, regenerative medicine, and the philosophy of personal 
identity. Public discussion often combines two distinct concepts: transplantation of an 
isolated donor brain into a recipient body, and transplantation of a recipient head onto a 
donor body. Neither procedure is clinically available. This critical narrative review 
evaluates the scientific evidence relevant to feasibility, identifies the interfaces that would 
require successful reconstruction, distinguishes cellular preservation from integrated 
neurological recovery, and proposes a responsible research agenda. Historical animal 
cephalic-exchange experiments established that a transplanted head could receive short-term 
blood flow, but they did not reconnect the spinal cord and therefore did not restore bodily 
motor or sensory integration. More recent BrainEx and OrganEx studies demonstrated that 
selected microcirculatory, metabolic, molecular, and cellular functions can be preserved or 
restored after prolonged ischaemia in pigs; importantly, these experiments did not 
demonstrate global organized brain activity, consciousness, or transplantability. The 
decisive barriers are not a single vascular anastomosis but simultaneous control of cerebral 
ischaemia-reperfusion injury, reconstruction of complete cervical spinal pathways, 
integration of cranial and autonomic systems, maintenance of cerebrospinal-fluid and 
endocrine physiology, prevention of alloimmune injury, and resolution of consent, identity, 
death determination, justice, and animal-welfare concerns. Current spinal-cord regeneration 
and neuromodulation research provides valuable component knowledge but remains far 
from the reproducible, high-bandwidth reconnection required after complete cervical 
transection. We conclude that a human brain or whole-body transplant is scientifically 
unvalidated and ethically unjustifiable at present. Legitimate progress should focus on 
lower-risk component research with predefined functional endpoints, independent oversight, 
transparent reporting, and explicit stop rules. The appropriate near-term objective is not a 
human transplant attempt, but rigorous solutions to organ preservation, neural-circuit repair, 
immune tolerance, and neuroethical governance.