Scientists map map neural wiring vocal circuits in songs

The researchers have mapped the long -term synaptic connections involved in vocal learning in zebra, discovering new details about how the brain organizes learned vocalizations, such as Birdsong.

The study, published as a revised pre -primers in ElifIt is described by publishers as having a fundamental significance and convincing evidence that clarifies how four distinct entrances to a specific region of the brain acts on three types of distinct cells to facilitate the learning and production of birds.

Understanding how the brain integrates sensory and motor information to guide learned vocalizations is crucial for studying both birds and human speech. The masculine yard song Finches Zebra It is a well-studied example of a naturally learned behavior and is controlled by a set of forearm regions interconnected in the dorsal ventricular ridge (DVR)-the aviary of the mammal neocortex.

Within this network, the premotor region of HVC is essential for birds to learn songs when they are young and to produce them when they are adults. While the major ways involved in the guidance of birds have been established, precise synaptic connections between different areas of the brain have remained difficult to determine due to technological limitations.

“The singing birds, like humans, learn their vocals by imitation and practice, based on Sensory feedback To improve their songs, “explains the main author Massimo Trusel, instructor in the Neuroscience Department, Ut Southwestern Medical Center, Texas, USA.” We have proposed to discover how different sensory inputs interact with HVC in the Zebra Finch song network to provide a framework to understand how the brain organizes the learned vocal behavior. “

To map the synaptic connectivity of the HVC region, Trusel and his colleagues used an optimized version of the optogenetic circuit cartography, which allowed them to manipulate auditory and thalamic entrances from the specific one-one brain regions and to record the activity of the HVC circuit. They could then follow the way in which the sensory and motor information converge on the circuits responsible for the production of songs.

They examined how the four main sensory entries interact with three key types of HVC cells: HVC-RA neurons, which send signals to the brain areas that control the movement for scales; HVC-AV neurons, which send motor signals to the auditory areas involved in processing the auditory feedback; and HVC-X neurons, which connect to the basal lymph nodes, a region that helps to learn and regulate song models.

Their discoveries suggest that HVC is organized into extremely structured neural modules, containing both projection and inhibitory interneurons, which work together on closely connected networks. This indicates that HVC acts as a hub for integrating sensory and motor information, the three types of projection neurons that have received adapted entries in their specific role in learning and production. Simply, HVC-RA neurons allow the production of stable, learned songs, and HVC-X neurons are responsible for learning and modifying the song.

The researchers also discovered an anterior unknown connection between the pre -inclusive partners of HVC Mman (the medial magnocellular nucleus of the anterior nidopall) and AV (Nucleus Avalanche). This suggests that Mman, who has previously thought that he plays a role only in the early learning of songs, can also help integrate auditory feedback with Engine controlallowing young birds to regulate their songs as they develop.

While this study provides new perspectives on HVC microcircuit, which ElifThe editors say it is essential for informing the learning and production models of songs, there are some limitations of the work. These include a potential gap in understanding the functions of development of development songs, because the research has focused on analyzing neural connections in adult birds.

“Our study offers the most detailed synaptic map of how different regions of the brain connect to HVC, a crucial center for learning and production of songs,” says the main author Todd Roberts, professor at the Neuroscience Department, Ut Southwestern Medical Center. “By revealing these wiring models, we highlighted the synaptic networks that allow the birds to structure their songs and improve their vocal skills.

“The optogenetic mapping technique that we used offers a powerful tool to explore other neural circuits, bringing us closer to understanding how the singing birds reach their remarkable vocal imitation skills.

“More, because the birds and human discourse It can be based on the circuits organized in a similar way, this work can also open the way to understand more about how our brains support the learning and production of speech and language. “