Wired for sound: A small fish's brain illustrates how people and other vertebrates produce sounds

In a study of midshipman fish, published online on June 14 in Nature Communications, the researchers identified two distinct groups of neurons that independently control the duration and the frequency of sounds used for calling.

While human speech and bird songs are far more complex than the grunts and hoots produced by some fish, the study provides a very basic wiring diagram of how the brain allows vertebrates to vocalize.

"If you can understand the simplest system, it provides a road map for understanding the fundamental working units in the central nervous system for how you build a vocal system," said Andrew Bass, Cornell professor of neurobiology and behavior and senior author of the paper.

In a 2008 Science paper, Bass and colleagues identified this same region of the brain in larval midshipman fish, showing how it is present in the brains of other animals, including primates. This suggests that the vocal networks in all vertebrates evolved from an ancestrally shared brain area that originated in fishes.

"Studies like these allow us to trace the evolutionary history of the brain," Bass said. "All animals, including humans, share many brain circuits for complex behaviors, including the use of sounds for social communication."

Co-authors include lead author Boris Chagnaud, postdoctoral researcher in the Bass lab, and Robert Baker, a researcher at New York University's Langone Medical Center; the authors collaborated at the Marine Biological Laboratory at Woods Hole, Mass. The study was funded by the Grass Foundation and National Institutes of Health.