During sleep, sporadically, it is possible to find neural patterns of activity in areas of the avian brain that are activated during the generation of the song. It has recently been found that in the vocal muscles of a sleeping bird, it is possible to detect activity patterns during these silent replays. In a new study, researchers from the Universidad de Buenos Aires and CONICET employed a dynamical systems model for song production in birds of the suborder Tyranni in order to translate the vocal muscles activity during sleep into synthetic songs.
The great kiskadee (Pitangus sulphuratus) in Beeville, Texas, the United States, in July 2011. Image credit: Tess Thornton / CC BY-SA 3.0 Deed.
“Dreams are one of the most intimate and elusive parts of our existence,” said Dr. Gabriel Mindlin, senior 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 few years ago, Dr. Mindlin and colleagues discovered that these patterns of neuronal activity descend to the syringeal muscles — a bird’s vocal apparatus.
They can capture sleep birds’ muscular activity data via recording electrodes, called electromyography, and then use a dynamical systems model to translate it into synthetic songs.
“During the past 20 years, I’ve worked on the physics of birdsong and how to translate muscular information into song,” Dr. Mindlin said.
“In this way, we can use the muscle activity patterns as time-dependent parameters of a model of birdsong production and synthesize the corresponding song.”
Trill electromyographic activity recorded during sleep and synthetic sounds generated by the dynamical model. Image credit: Döppler et al., doi: 10.1063/5.0194301.
Many bird species have complex musculature, so translating syringeal activity into song is a bit of a challenge.
“For this initial work, we chose the great kiskadee (Pitangus sulphuratus), a member of the flycatcher family and a species for which we’d recently discovered its physical mechanisms of singing, and presented some simplifications,” Dr. Mindlin said.
“In other words: we chose a species for which the first step in this program was viable.”
Hearing the sounds emerge from the data of a bird dreaming about a territorial confrontation with a raised crest of feathers — a gesture that during the day is associated with a trill used in confrontations — was incredibly moving for the authors.
“I felt great empathy imagining that solitary bird recreating a territorial dispute in its dream. We have more in common with other species than we usually recognize,” Dr. Mindlin said.
The study presents biophysics as a new exploratory tool capable of opening the door for the quantitative study of dreams.
“We’re interested in using these syntheses, which can be implemented in real-time, to interact with a bird while it dreams,” Dr. Mindlin said.
“And for species that learn, to address questions about the role of sleep during learning.”
The study was published in the journal Chaos.
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Juan F. Döppler et al. 2024. Synthesizing avian dreams featured. Chaos 34 (4): 043103; doi: 10.1063/5.0194301
