At midnight tonight, countless drunken partygoers will join together arm-in-arm and muddle through “Auld Lang Syne” to ring in a new year. And they may be just tipsy enough to think that it sounds good. However, don't despair you uninhibited revelers: humans aren’t the only ones who sing worse when they’re drunk. As it turns out, so do birds. And drunk birds may help researchers understand the brain basis of how humans create language.
We all know booze makes people slur their words, but speech impairment is still one of the least understood, and intriguing, effects of alcohol. The trouble is finding animals to study in the lab that have speech abilities similar to humans’. That’s why zebra finches were invited to the party. Male zebra finches both learn and produce sounds in a strikingly similar fashion as humans. Both groups require prolonged exposure to a parent or tutor that provides the auditory feedback to start forming words, or in the case of finches, songs. In fact, the same genes control birdsong and human speech.
Researchers purchased adult male zebra finches from a commercial breeder and set them up in individual cages. For four days they gave half the birds juice to drink and other half juice spiked with 6.5 percent ethanol. They coaxed the birds into song by playing recordings of a female zebra finch, and recorded the output. Throughout the experiment, researchers monitored the birds’ behavior and health to ensure the booze wasn’t having ill effects. And from the outside, the birds with spiked juice seemed just fine. However, you could tell they were buzzed when they started to sing. Zebra finch songs are normally highly organized and contain specific notes to hit. But a computer analysis of the drunk birds' songs found that they sang more quietly and they muddled key notes. The notes that were compromised, researchers suspect, are produced by different brain circuits than those that stayed consistent. It appears that alcohol affects some speech pathways in the brain’s circuitry more than others. Researchers published their findings last week in the journal PLOS One.
The experiment proved that zebra finches would indeed consume alcohol — an important first step. But more importantly, it provided evidence that zebra finches are an ideal animal to study the effects of alcohol on a cognitive skill with similarities to human speech. Since the song control brain circuitry is well understood in zebra finches, future research can examine alcohol’s effect on speech at a finer resolution using a variety of methods. One potential application of the study, researchers said, would be to reliably detect even mild intoxication through cues hidden in our speech. But since that technology doesn't yet exist, belt out those songs tonight — and happy New Year.
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