Scientists are trying to create the brain of humans and other animals as close as possible to the present. This is important for experiments, organ transplantation, and the study of diseases. It is possible that in the near future it will be possible to grow samples with consciousness in test tubes.
Headless pigs
In April 2018, the journal Nature published an open letter from 17 leading neurophysiologists in the world calling for the development of rules and restrictions for experiments with artificially grown nerve tissue, since very soon it will be possible to recreate not only the structures, but also the functions of the brain. In other words, it is very likely that some laboratory samples are about to show signs of consciousness, and you need to be prepared for this. In fact, this was a response to a report by scientists at Yale University that they kept the pig's brain, separated from the body, alive for 36 hours. A specially designed BrainEx heated pump system and synthetic blood substitute were used to restore blood circulation to the brains of more than a hundred animals four hours after they were beheaded. In the brains reanimated in this way, billions of living, efficient nerve cells were found. However, there was no electrical activity - this was shown by an electroencephalogram. Therefore, scientists concluded that the brain is alive, but is in a coma, which means there is no consciousness. According to the authors of the work, the revitalized pig brains can further serve as material for testing new drugs for cancer or Alzheimer's disease. In addition, technically, this discovery can be seen as a way to keep an organ alive for further transplantation or to make a brain grown in a laboratory work. According to the authors of the work, the revitalized pig brains can further serve as material for testing new drugs for cancer or Alzheimer's disease. In addition, technically, this discovery can be seen as a way to keep an organ alive for further transplantation or to make a brain grown in a laboratory work. According to the authors of the work, the revitalized pig brains can further serve as material for testing new drugs for cancer or Alzheimer's disease. In addition, technically, this discovery can be seen as a way to keep an organ alive for further transplantation or to make a brain grown in a laboratory work.
Brains in a test tube
This problem has been closely tackled since the mid-2000s, when Japanese biologists have consistently grown the cerebral cortex, pituitary gland and optic cup - an outgrowth of the diencephalon wall in the embryo of mammals. Stem cells have been used everywhere as building materials. In 2012, American scientists obtained in laboratory conditions a forebrain with a cortex, the developmental stage of which corresponded to the brain of a human embryo at the end of the first trimester of pregnancy. Experts at Stanford University went further and three years later created small lumps that mimic the brain of a newborn baby immediately after birth. At the same time, researchers from Ohio University grew a full-fledged human brain from stem cells, corresponding to the level of a five-week-old embryo. According to the authors of the experiment,almost completely reproduced all the main areas of the brain, but the vascular system was lacking. Therefore, he could not further develop and function.
Small but remote
Test tube brains are still very small. For example, the dimensions of Stanford samples are only three to four millimeters. The Ohio-made organ is no bigger than an eraser on the tip of a pencil.
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The main reason for the diminutiveness is the lack of oxygen and nutrients, which the vascular system delivers to the internal organs. Artificial brains do not have such a system, and the only possible way for the molecules of necessary substances to penetrate is through tissues.
In addition, the nutrient solution in which brains are grown is not able to fully reproduce the specific microenvironment in which the human brain grows and develops. This, in turn, limits the access of signaling molecules that transmit signals, or stimuli, from cell to cell. In a living organism, disturbances in signal transmission lead to the development of cancer, autoimmune diseases and diabetes, in artificial ones - to size limitation.
Neanderthal brain
One of the possible solutions is the creation of chimera animals, that is, the transplantation of the grown parts of the human brain to some kind of laboratory animal. The first experiments were carried out on mice. In 2015, specialists from the Salk Institute for Biological Research (USA) announced that they transplanted organelles grown in a test tube into the brain of rodents and managed to connect them to the circulatory system of animals. After three months, 80 percent of the mice had artificial neural tissue engrafted. True, as the authors of the work note, the operated rodents did not become smarter: their behavior did not differ from usual. Scientists believe that such research will revolutionize regenerative medicine and allow grown cells to be implanted in humans. If the experiments are successful, it will be possible to transplant any organelles created in a test tube - including Neanderthal ones. Not so long ago, American biologists obtained the brain of a Neanderthal in the laboratory. For this, a mutation characteristic of the genome of ancient people was introduced into the DNA of stem cells. One mutation radically changed the structure of neural connections and even the shape of organelles.
Neurons in Neanderthal nerve tissue migrated faster and formed fewer synapses compared to the human brain. According to the study authors, this is similar to what happens in organelles made from autistic cells. But artificial neural tissue itself says little about how the adult brain will function - and this is what scientists are especially interested in.
To understand all the processes taking place in the Neanderthal brain, you need to fix electrical activity in it, which indicates consciousness. And here scientists will enter the gray zone, which the authors of the April letter warned about. They will have a wonderful experimental model that will help answer many questions, but this model will feel everything and probably understand.
Alfiya Enikeeva