400 million-year-old birth of voices
A male Gulf toadfish, linked to the evolution of human voices
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Friday, 18, Jul 2008 11:39
The brain mechanism that drives people's voices began more than 400 million years ago with the evolution of a tiny fish, according to a new study.
US researchers claim to have found that the neural network behind sound production in vertebrates can be traced back to before animals first moved onto dry land.
They used fluorescent dyes to identify distinct groups of neurons in the brains of larvae of midshipman fish, a species known for the loud humming sounds adult males generate with their swim bladders to attract females to their nests.
Using a technique called laser-scanning confocal microscopy, the researchers observed clusters of cells in part of the developing brain as they formed connections and grew into networks that control vocalisation in mature fish.
They then compared this system to that behind vocalisation of amphibians, birds, reptiles and mammals.
The results showed that while networks vary in how complex they are, their fundamental attributes the same.
Writing in the journal Science, the researchers argue that their findings put human speech – and social communications of all vertebrates – in evolutionary context.
"We propose that the vocal basis for acoustic communication among vertebrates evolved from an ancestrally shared developmental compartment already present in the early fishes," they conclude.