Researchers from Cornell University have identified areas of the brain in fish that reveal the basic circuitry for how humans and other vertebrates communicate using sound.
Over 500 species of fish are known to use sound such as grunts, drumming, croaks and clicks to communicate, including Atlantic croakers, toadfish (pictured above) and damselfish.
Now a study by reseachers from Cornwell University has used Midshipman fish (Porichthys notatus) to identify the areas of the hindbrain that are used in vocalisations using tiny electrodes recording the activity of the nerve cells.
They found two different groups of neurons independently control the duration and frequency of the sounds produced by the fish’s swimbladder by controlling the movement of the muscles.
This is similar to the way in which the human larynx and bird syrinx are controlled and 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 vocalise.
One of the authors Professor Andrew Bass from the Department of Neurobiology and Behaviour at Cornell University said: "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."
Professor Bass added that prior to this study it was relatively unknown how brains co-ordinated vocalisation but that this study demonstrated that it actually works to a similar pattern as that seen in the control of walking.
Three years ago the same team demonstrated that the same region of the brain could be seen in larval Midshipman fish and a number of other animals including primates. This suggested 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 behaviours, including the use of sounds for social communication."
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