Long before a baby’s ears are functional, the brain is already building the circuitry needed for hearing, according to new research from Johns Hopkins University. Published in the journal Science Advances, the study in mice identifies a previously unknown neural “shortcut” that organizes the auditory system before birth, offering new insight into how the auditory system prepares to process sound and eventually learn language.

While it’s well-known that sound travels from the ear to the auditory cortex, the brain’s hub for hearing, Johns Hopkins researchers discovered a new neural circuit that bypasses the ear entirely. Their findings show that the frontal cortex—the region involved in vocalization—sends signals directly to the auditory cortex, allowing the developing brain to activate hearing-related circuits before external sounds can be heard.

“Our results provide the first direct functional evidence of this biological shortcut that doesn’t go through hearing,” says senior author Patrick Kanold, a professor of biomedical engineering and neuroscience at Johns Hopkins. “It’s a novel brain activity source that can shape the earliest development in mammals, like interpreting information and discerning complex sounds.”