Scientists have observed a mouse whose brain cortex is largely composed of human cells. As the animal wandered around a small arena, multiple cameras recorded its path, and a computer charted its position and speed, leaving traces on a monitor that resembled Pong.
The reason for the close observation, according to MIT Technology Review, is that nearly half of the mouse's brain volume had been replaced with human cells. The report describes the effort to study such a creature, though the specific research goals are not fully detailed in the excerpt.
The scene—a rodent moving under camera surveillance while its every movement is translated into digital traces—illustrates how far brain-chimera research has come. It also invites questions about the boundaries between species and what it means for an animal to carry a significant amount of human neural tissue.