In a groundbreaking study published in the journal *Nature*, researchers at Stanford University led by neuroscientist Sergiu Pașca have created a mouse model that incorporates human brain cells, comprising nearly half of its brain volume. The experiment involved meticulously tracking the mouse’s movements within a controlled arena, where its positioning and speed were monitored through advanced computer systems, revealing fascinating insights into how these foreign cells interact with a non-human brain.
Building on previous research where human brain organoids were successfully integrated into young rodents, Pașca’s team has taken a significant leap. They genetically modified mice to hinder the full development of their brains, specifically targeting the cortex and hippocampus—two crucial regions for cognitive function. This alteration provided ample space for the human cells to proliferate, which demonstrated remarkable adaptability, as the modified mice displayed relatively normal behaviors despite their cognitive impairments. When tested in a maze, these mice struggled with memory retention, indicating a direct connection between the presence of human cells and cognitive functions.
The implications of this research extend beyond mere curiosity, offering potential avenues for studying brain injuries and cognitive disorders. As Carsten Charlesworth, a fellow Stanford scientist not involved in the study, notes, this research exemplifies the extraordinary fusion of genetic engineering and stem-cell technology, pushing the boundaries of biological understanding. However, ethical considerations loom large, especially regarding the possibility of creating conscious beings from such experiments. Pașca has expressed caution against extending this type of research to higher species like primates, emphasizing the moral responsibilities that come with manipulating cognitive functions in animals. The ongoing dialogue about the ethical ramifications of such innovations will play a critical role as the field progresses.
Source: Meet a mouse whose brain cortex is made up of human cells via MIT Technology Review