Jackson W.: How can the melodic sound of a songbird help scientists understand the human brain? And in particular, how young children learn to speak? And what could scientists studying the human brain learn from these sounds to help kids with autism or other speech disorders? We'll find out. I'm Jackson [Witt 00:00:00:21], and welcome to the BrainWaves Podcast, brought to you by UT Southwestern Medical Center's O'Donnell Brain Institute.
Jackson W.:  I'm in the institute's songbird lab where a new White House funded brain research effort is helping researchers map the neural process as these birds learn mating songs. Their goal is to understand how the brain works during vocal learning and perhaps one day target the genes that cause speech disorders.
Jackson W.: I'm with Dr. Todd Roberts, assistant professor of neuroscience who oversees the songbird lab. Welcome, Dr. Roberts.
Todd Roberts: Hi. Nice to be here.
Jackson W.: Okay, Dr. Roberts, what's the connection between the tiny brains of the songbirds and the human brain?
Todd Roberts: The Brain Initiative Project, that my lab is working on, is trying to map how neurons in the brain that control the birds' singing behavior are connected up with each other. So we are trying to go from a dynamic picture of how hundreds of cells are active when a bird is singing to a map of how those cells actually talk to each other. Basically, what we want to know is how do maps of neurons in the brain relate to the production of complex behaviors?
Jackson W.: What can you tell us about the insights?
Todd Roberts: We have a pretty good view of how different regions of the brain are active when a human or another animal performs a motor behavior. But we're looking at it with that wide angle lens. What we want to do is take that view and then get down to the level of individual cells, or in connections between those cells, and understand at a cellular level or at the level of connections between individual neurons, how behaviors are represented in the brain.
Jackson W.: Let's talk about the songbirds. Why did you choose the Zebra Finch as your model for your research?
Todd Roberts: One of the reasons that we study them is that they learn to imitate their songs during developmental sensitive period. And a young bird starts off with a very noisy, rambling vocalization and it sounds like this.
Todd Roberts: So as you can hear, it's not a very pretty song. It sounds really screechy. So this is a bird that's just over a month old. And the goal of this young bird during development is to go from this really noisy, screechy vocalization to something that is good enough to attract a female bird as an adult.
Todd Roberts: So he needs to learn his mating song. And he does this by first memorizing the song of his father and then going through a phase of extensive practice where he'll practice a song 2,000 to 5,000 times a day for over a month. So performing his song well over 100,000 times during development. And eventually, he'll sing an adult song that is highly stereotyped and is something that females are highly attracted to. And this is an example of an adult Zebra finch song.
Todd Roberts: So to our ears, this isn't the prettiest song. It sounds a little bit like Woody Woodpecker. But the adult bird repeats the same syllables in a song several times in a row. And when he repeats these syllables, he does it with extremely high precision. And this was one of the reasons this is a great model system, because they only learned this one song when they're young and then they only produced this one song for the rest of their life.
Todd Roberts: They use it as a courtship song, but they have to do it very, very precisely. And we can control what song that they're trying to learn in our laboratory settings. And we can also map how the brain's changing as they're first forming a memory of the song that they want to copy and as they go through this daily practice over the course of many, many days.
Jackson W.: Having heard what you can do with the songbirds in the lab, how can this help scientists better treat patients with neurodevelopmental conditions?
Todd Roberts: I think what we've learned over the last few decades in neuroscience is that most disorders that affect the nervous system fundamentally affect how synaptic connections between neurons are regulated. So in many neural developmental disorders that affect learning and memory, there's either an overabundance of connections, or there's too few connections between the neurons and the brain. And what's really been lacking is technologies that allow us to study in behaving animals and during dynamic changes to the connections in the brain, how individual neurons are actually connected to each other. So the hope is to provide a dynamic picture of how the brain and cells in the brain communicate with each other and how that changes during learning and memory.
Jackson W.: Another method you use in your lab is a the FOXP2 family genes where you're able to turn off a bird's speech development. Tell me more about that.
Todd Roberts: The main goal of our work with FOXP2 is to try to understand whether or not we can dissect different parts of the sensitive period for learning and understand whether we can restore function of learning a song in a bird by turning this gene back on at different time points during development. So what we have developed is a tool that we can express using viruses in the brain that will allow us to turn off FOXP2, this gene, in specific cells in the brain. And then when we want, we could turn it back on.
Jackson W.: Now what about if you disrupt FOXP2?
Todd Roberts: What happens is that they struggle to learn the song and they aren't able to accurately produce the song that their father taught them later in life. And this type of disruption in song is very similar to the type of verbal disruptions that you see in humans that have gene mutations in FOXP2. And this allows us to do both experiments where we are disrupting gene function but also rescue gene function at different time points.
Jackson W.: That being said, how can it help us?
Todd Roberts: So for example, speech learning in humans occurs early in life. And if you don't have the correct exposure or the opportunity to learn speech by the time you're a teenager, or perhaps a second language, for example, then it becomes much more difficult later in life. And the same thing is true in songbirds. And so they go through a developmental stage early in life called sensory motor learning, where they have heightened brain plasticity and allows them to learn their song. And what we're interested in understanding is whether or not we can restore the function of this gene that seems to be critical for development of speech and development of song in birds. If we can restore the function of this gene later in life and reopen a period of plasticity where the birds can then learn their song.
Jackson W.: Thank you Dr. Roberts. We'll sing your praises, so to speak, in the future as your fascinating research continues.
Jackson W.: This has been BrainWaves from the University of Texas Southwestern Medical Center's O'Donnell Brain Institute. If you would like more information on vocal learning, please visit us at utsouthwestern.edu and search for Dr. Todd Robert's lab I'm Jackson Witt. Thanks for listening.