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Scientists have been able to teach birds simple songs they’ve never heard before by selectively activating specific neurons in their brains – effectively implanting false memories.
Using the process of optogenetics, where light is used to control living tissue, the team was able to activate certain neuron circuits in the birds and get them to memorise new tunes.
The amount of time the neurons were kept active corresponded to the length of the notes in the song the birds learned.
The study could teach us more not just about birdsong, but also how vocal learning and language development happens in the human brain as well.
The zebra finches involved in the experiment usually learn songs from their fathers and other adult birds, memorising the notes and practising tens of thousands of times to get it right.
In this case, new melodies were successfully introduced without any parental input, so the birds were essentially mimicking tunes they’d never heard before.
What prompted the research is not a need to create a new songbook for neighbourhood birds, but to understand how language is learnt – how young birds and perhaps young babies pick up language from their parents.
Further down the line we might one day be able to understand how to fix problems in language development using the same techniques used here.
“This is the first time we have confirmed brain regions that encode behavioural-goal memories – those memories that guide us when we want to imitate anything from speech to learning the piano,” says neuroscientist Todd Roberts, from the University of Texas Southwestern Medical Centre.
“The findings enabled us to implant these memories into the birds and guide the learning of their song.”
Of course going from birdsong to human speech is a big leap, and a lot more research is going to be needed here. Scientists often make use of zebra finches in studies though, because their vocal development is similar to humans in a lot of ways.
The team found that pathways between the NIf (nucleus interfacialis) and HVC (high vocal centre) brain regions, both previously linked to sensory and motor functions, were crucial in both forming the ‘memories’ of a song and then learning to sing it.
“We’re not teaching the bird everything it needs to know – just the duration of syllables in its song,” says Roberts. “The two brain regions we tested in this study represent just one piece of the puzzle.”
We’re still a long way from being able to teach birds the greatest hits of Queen or the national anthem of the country in which they live, but it’s an exciting step forward in terms of knowing what’s going on in the brain as it learns this sort of information.
One route for further research is examining other areas of the bird brain that might be relaying information to the HVC region – and that could lead to being able to analyse and manipulate the pitch and combination of song syllables, as well as their duration.
“The human brain and the pathways associated with speech and language are immensely more complicated than the songbird’s circuitry,” says Roberts. “But our research is providing strong clues of where to look for more insight on neurodevelopmental disorders.”
The research has been published in Science.