Marsupial joeys could clarify human brain development

Above, the fat-tailed dunnart, Sminthopsis crassicaudata. (Credit: Getty Images)

New research finds features of early human brain development in the brains of marsupials called fat-tailed dunnarts.

The finding could lead to a better understanding of brain patterns linked to neurodevelopmental conditions like autism spectrum disorder (ASD), says lead author Rodrigo Suárez of the University of Queensland’s Queensland Brain Institute and School of Biomedical Sciences.

“Marsupials are mammals born at extremely early stages—the equivalent to mid-gestation in human terms,” says Suárez. “Most marsupial brain development happens postnatally, inside the mothers’ pouch. Because of this, we’ve been able to study patterns of neural activity in the Australian native fat-tailed dunnart and found they’re similar to those in the human brain in utero.”

The research used light indicators to record the electrical activity of neurons in marsupial joeys.

“We followed the onset and maturation of complex activity patterns, using advanced microscopy to read how the joey’s developing brain cells first communicate,” Suárez says.

“There were distinct patterns from the outset indicating not only that neural activity begins before sensory experience, but that unique electrical features in newborn cells might be crucial for the healthy establishment of brain connections.”

Suárez says it is well established that human babies respond to stimulation well before birth. “But exactly when, where, and how electrical activity begins in the developing brain has remained largely unknown,” he says. “This is mostly because only mammals have evolved a cerebral cortex—the wrinkly surface of our brains that controls sensory motor and cognitive tasks—and most experimental models can’t survive at such early stages outside the uterus.”

Suárez says studying marsupials could help researchers go further back in brain evolution. “These findings highlight early processes of brain development that arose millions of years ago, and are ongoing with little change, likely influencing the evolution and diversification of the cerebral cortex.”

The study appears in the Proceedings of the National Academy of Sciences.

Source: University of Queensland