He has half a rat’s brain and half a rat’s mind. This Frankenstein may be salvation for the elderly

American scientists used a special technology to remove nerve cells from developing mice and replace them with mouse stem cells that developed into neurons. This is how hybrid brains were created: part rat, part rat. The animals developed naturally, which is promising for neuronal regeneration therapy.

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The research was conducted by two independent teams, and they published their results in the journal cell. Not only does it deepen our knowledge of brain tissue development, but it also offers new possibilities for treating neurological disorders.

From Mice to Frankenstein Men

A team of scientists from Columbia University Under the supervision of Prof. Christine Baldwin used mouse stem cells to restore olfactory nerve circuits in mice. These neural networks control the sense of smell. This is the first time that an animal has been able to use the sensory systems of another species to perceive and respond to the world. This is evidence of how flexible the brain is in integrating external neurons.

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Professor Christina Baldwin says:

This study shows us how we can increase neuroplasticity so that the brain can accept other types of inputs, such as human-machine interfaces and transplanted stem cells.

On the other side A team of neurobiologists from the University of Texas Southwestern Medical Center Take a different approach. Scientists have developed a CRISPR-based platform to identify genes essential for tissue development, with a particular focus on HESX1, which is critical for mouse forebrain development. By silencing this gene and using mouse stem cells, forebrain tissue was generated, providing a unique view of brain evolution across species.

Professor Jun Wu of the University of Texas Southwestern Medical Center says:

The ability to evolve nervous tissue from one type to another can help us understand brain development and evolution. There are no good behavioral tests to distinguish between rats and mice, but our experience shows that rats with rat forebrains do not behave “differently.”

Both teams used a method known as blastocyst complementation. A blastocyst is a stage of embryonic development consisting of a trophoblast and an embryonic nodule – a group of dividing cells that make up a fertilized egg. Blastocyst complementation involves injecting stem cells from one type into poorly growing blastocysts from another type. This technique has previously been used to create pancreases in mice using mouse stem cells.

Professor Wu’s laboratory showed that inactivating the HESX1 gene causes mice to lack a forebrain. This part of the brain can be regenerated by introducing rat stem cells into the developing embryo. Surprisingly, the forebrains derived from rat cells developed at a similar rate to mice, demonstrating the ability of rat neurons to adapt in a rat environment.

In a study conducted by Columbia University, researchers injected stem cells from mice into mouse embryos and used specific genes to silence the sensory neurons responsible for the sense of smell. This model reflects the impairment of communication between neurons in the brain that is observed in neurodevelopmental disorders. Blastocyst supplementation restores mouse olfactory circuits.

Professor Christine Baldwin adds:

You could see rat cells in almost the entire mouse brain, which was quite surprising to us. This tells us that there are few barriers to input, suggesting that many types of neurons in mice could be replaced by similar neurons in mice.

The implications of this research may help develop potential strategies to restore brain functions lost in Parkinson’s and Alzheimer’s disease.