A team of biologists co-led by the University of Iowa has found a gene that is integral to animal and human hearing.

The biologists report in the Journal of Neuroscience that the gene, called Neurod1, orchestrates a sequence of gene expression activities that are essential for forming the frequency-specific connection between the ear and the brain.

The finding is important because it clarifies how different tunes or frequencies captured by hearing organs are transmitted — and interpreted — by animal and human brains. As the authors report, frequency-specific connections of both ears are necessary for directional hearing when comparing sound intensity and the time of arrival. 

“We show that without Neurod1, this wiring is nearly completely random,” says Bernd Fritzsch, professor in the UI’s Department of Biology and a co-corresponding author on the paper. “We also show that central sound processing is random and thus we can conclude that a miswired input cannot be corrected by central information processing.”

The researchers based their findings from experiments with mice. They say Neurod1 also is present in humans, and it is likely that the gene has the same importance to hearing in humans as in other animals.

Fritzsch collaborated with researchers in the Czech Republic on the experiments. The work was funded by the National Institutes of Health, through a grant to Fritzsch, and by scientific and higher-education institutions in the Czech Republic.