Birds Sing in Their Sleep – and Now We Can Decipher Their Dreams
taylorvich writes:
https://newatlas.com/biology/bird-sleeping-dream-song/
Researchers have tracked muscle contractions in a bird's vocal tract, and reconstructed the song it was silently singing in its sleep. The resulting audio is a very specific call, allowing the team to figure out what the bird's dream was about.
When birds sleep, the part of their brains dedicated to daytime singing remains active, showing patterns that resemble those produced while awake. Researchers from the University of Buenos Aires (UBA) previously demonstrated that these brain patterns activate a bird's vocal muscles, enabling them to silently 'replay' a song during sleep.
But, until now, it hasn't been possible to map how that nocturnal activity gets processed. In their new study, the UBA researchers turned the vocal muscle movements made during avian dreaming into synthetic songs.
"Dreams are one of the most intimate and elusive parts of our existence," said Gabriel Mindlin, a specialist in the physical mechanisms behind birdsong and corresponding author of the study. "Knowing that we share this with such a distant species is very moving. And the possibility of entering the mind of a dreaming bird - listening to how that dream sounds - is a temptation impossible to resist."
A bird's vocal sounds are made by a unique organ only they possess, the syrinx. Located at the base of the windpipe (trachea), passing air causes some or all of the organ's walls to vibrate, while a surrounding air sac acts like a resonating chamber. The pitch of the sound produced depends on the tension surrounding muscles exert on the syrinx and the airways.
[...] Custom-made electromyography (EMG) electrodes were implanted in the birds to measure the muscle response and electrical activity in the obliquus ventralis muscle, the most prominent muscle producing the kiskadee's birdsong. EMG and birdsong audio were recorded simultaneously while the birds were awake and asleep. An existing dynamical systems model of the kiskadee's sound production mechanism was used to translate the information into synthetic songs. In basic terms, a dynamical systems model breaks down what occurs in the syrinx when sound is produced into a series of mathematical equations.
[...] Analyzing muscular activity during sleep revealed consistent activity patterns corresponding to the trills produced by kiskadees during daytime territorial fights. Interestingly, the 'dreaming trills' were associated with raised head feathers, the same as during the daytime. The researchers created a synthetic version of one of the trills from the data they'd collected.
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