Female canaries, which do not normally sing, have the ability to do so throughout their lives

The human brain, once thought to lose its resilience after childhood, continues to remodel itself throughout life—recovering from injuries, learning new skills, and adapting to challenges.

Songbirds show similar neuroplasticity on a seasonal basis, with changes in their brains, activation of elaborate songs during breeding seasons, and recovery of full vocal repertoire even after years of reduced singing. This raises a fundamental question: How does the brain preserve these complex abilities when they are not actively being used?

A new study from the Max Planck Institute for Biological Intelligence tackles this by focusing on female canaries, which don’t normally sing, but nonetheless contain the complete neural machinery for singing. Just as humans have specialized brain regions for language, songbirds have developed these specialized regions for singing — and the ability to sing in canaries is partly inherited and partly learned through practice.

By giving the females testosterone—a hormone that increases in males during breeding season—the team could watch what happens over several weeks as these dormant singing abilities are replaced and the females fine-tune their newfound vocalizations.

Appears at work Proceedings of the National Academy of Sciences.

Increase activity

Using traditional imaging methods, scientists had previously observed HVC—a brain region important for singing—that appeared more pronounced in images of singing than non-singing canaries, such as during the breeding season.

However, by tracking brain cells in HVC, a combination of advanced microscopy and gene expression studies revealed something different. Neurons didn’t divide or multiply as it seemed to—instead, they were becoming more active, strengthening connections, increasing activity, and changing gene expression, and were easier to detect, creating an illusory growth in anatomical images.

“Instead of enlarging the brain region, gene mapping showed that testosterone orchestrates these changes in the HVC without changing its size,” says researcher Shoven MA from the Department of Behavioral Neurobiology at the Max Planck Institute in Sivsen.

“Importantly, this means that the HVC maintains its size and neural architecture even when not in use, allowing birds to regain complex singing abilities without singing. What’s so exciting to me about this discovery is that it’s a great example of how the brain doesn’t need to rebuild the structure from scratch: the neural machinery is ready, expected and fine-tuned.” is.”

A constant ability to sing

The singing capacity proved to be remarkably constant. The researchers even encouraged singing in seven-year-old females, well beyond their typical life in the wild.

“This project has been an important and holistic effort for the department. We have improved genomic tools to assess the molecular basis of canary song behavior at high resolution. This has ranged from genome sequencing to sophisticated bioinformatic methods to reveal brain architecture. Frankel-Welch’s, Department of Behavioral Neurobiology researcher

“By studying how individual cells change their behavior, we are uncovering the fundamental principles of brain plasticity and how the brain maintains its capacity for advanced changes throughout life,” says Manfred Gehr, head of the department.

“Understanding these mechanisms—how hormones trigger changes in brain cells, how neural circuits maintain their structure and flexibility—can shed light on broader principles in brain plasticity and therefore better understand broader questions such as how aging brains maintain their ability to adapt and promote recovery after stroke or injury.”