Human-Derived Cortical Tissue Reportedly Connected to Mouse Nervous Systems

Grafted tissue forms blood vessels and neural connections

ScienceAlert reports that researchers transplanted human cortical organoids—three-dimensional tissue grown from human cells—into newborn mice genetically engineered to develop little of their own cerebral cortex and hippocampus. The grafts reportedly expanded into the vacant cortical space, formed blood vessels, connected with the mouse nervous system, and sent some projections into the spinal cord. The report says the grafted mice performed above chance in a Y-maze, unlike ungrafted mice with depleted cortex and hippocampus; the researchers cautioned that this alone does not show human neurons directly caused the behavior.

Human brain organoids grown in dishes lacked a blood supply, sensory input, and connections to a living nervous system.

The reported model moved human-derived cortical tissue from isolated organoids to grafts that expanded within mice and connected with their nervous systems.

The model reportedly provides human-derived cortical tissue with circulation and access to a functioning animal nervous system, conditions absent from dish-grown organoids. It also produced neuron types that had been difficult to generate in other models, including cells resembling von Economo neurons. The work raises animal-welfare and ethical questions alongside possible avenues for studying neurological and psychiatric disorders.