Tuning into chook songs for clues to autism | Spectrum
The communication and language difficulties seen in people with autism are difficult to study in animals for obvious reasons. However, scientists have found parallels between human speech and the song of some birds. Young male zebra finches (Taeniopygia guttata) learn to sing by listening to and mimicking adults, much like children learn to speak. In both songbirds and young children, this learning takes place during a “critical phase” at the beginning of development and involves analog neural circuits. Because of these similarities, songbirds like zebra finches have become important models for studying language learning in autism.
Over the past few decades, scientists have developed a detailed understanding of bird song circuits, says Todd Roberts, associate professor of neuroscience at the University of Texas’ Southwestern Medical Center at Dallas. That background “gives us a really good foundation” to assess the function of autism-related genes that might play a role in language, he says: Scientists know exactly where to look in the songbird brain for the effects of certain genes have to.
Many areas of the human brain that control language show similar gene expression profiles to the song-related regions in birds. About a decade ago, researchers began documenting how some autism-related genes such as CNTNAP2 are expressed at high levels in bird song brain regions, suggesting that these genes play a role in birds’ ability to sing. Since then, they have followed how the expression of certain genes associated with autism change during song learning. When young male zebra finches sing, levels of an autism-related protein called reelin rise in a song-related region called Area X. So does the amount of an activated form of a protein called DAB1, which is also linked to autism. So these genes may be involved not only in bird singing, but also in learning to sing – and perhaps in human language learning as well.
For the past five years, researchers have perturbed the expression of various genes linked to autism in zebra finch brains to investigate the role of the genes in song learning. They found that reducing the production of CNTNAP2 in key areas of song learning in the brains of young zebra finches interfered with the birds’ ability to learn songs from their fathers. They have suppressed the expression of FOXP1 or FOXP2, autism-related genes involved in human language, in the basal ganglia of birds and found that this also interferes with song learning. And a study published earlier this year suggested that dampening the production of FOXP1 in a singing region called HVC prevents young birds from learning new songs, even though they can still practice and perfect songs they already know, suggesting a role for this Gene in some aspect suggests the song learning process.
Birdsong is not a perfect analogue of language. A zebra finch’s song is a single repetitive sequence, simpler than the rich tapestry of human language. “We can recombine these sounds in such a way that they have many different meanings, while the meaning of the bird is really just, ‘Hey, I want to be your mate,'” says Caitlin Aamodt, a postdoctoral fellow with Eric Courchesne and Nathan Lewis of der University of California at San Diego.
But the similarities are strong enough that songbirds could help researchers understand language difficulties in autism and provide pointers on how to improve language learning in autistic people. The birds could even provide a platform for testing treatments designed to strengthen language skills. “One of the ultimate goals would be to understand what stages of development you need to intervene and how strong or persistent those interventions need to be,” says Roberts.
Quote this article: https://doi.org/10.53053/BCCO9981