A Boston University team used electron microscopy-based connectomics, a very high-powered imaging method, to study neurogenesis in the zebra finch, a small Australian songbird that learns new songs. The technique allowed researchers to follow the birth, migration and maturation of new neurons as they moved through adult brain tissue toward existing circuits. The findings appear in Current Biology and may inform future therapies for humans.
The researchers found, unexpectedly, that new neurons often tunnel directly through mature brain tissue. The cells appeared to squish and shove past established structures and mature neurons instead of carefully avoiding them. Benjamin Scott, a BU assistant professor and the study’s corresponding author, said, "We found that in songbirds, new neurons in the adult brain behave like explorers forging a path through a dense jungle."
Scott added, "This potentially disruptive behavior may help explain why humans and other mammals have limited capacity to regenerate brain tissue in adulthood, leaving us more vulnerable to neurodegenerative disorders such as Alzheimer’s disease." He offered two interpretations: human brains might have evolved to limit neurogenesis after birth to protect established circuits and memories, or the bird neurons show movement without glia scaffolds, implying that repair might not always require those scaffolds and could inform stem-cell approaches.
Researchers in Scott’s lab are using single-cell RNA sequencing to identify genes active in migrating neurons and to learn which cells they interact with. The study included collaborators from the MRC Laboratory of Molecular Biology and the Max Planck Institute for Biological Intelligence and was funded with support from the BU Neurophotonics Center.
Difficult words
- connectomics — Study of neural connections and their organization.
- neurogenesis — Process of forming new neurons in the brain.
- migration — Movement of cells from one place to another.
- maturation — Process of becoming fully developed or functional.
- circuit — Network of connected neurons that directs signals.circuits
- glia — Support cells in the nervous system.
- single-cell RNA sequencing — Method to measure gene activity in individual cells.
- regenerate — Grow or repair damaged tissue or organs.
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- Do you think limiting neurogenesis after birth could help protect memories? Why or why not?
- How might the discovery that neurons can move without glia scaffolds change approaches to brain repair?
- What challenges could researchers face when applying findings from songbirds to human therapies?
Related articles
Connie Nshemereirwe: linking science, policy and education in Africa
Connie Nshemereirwe is an educational measurement specialist and former engineer who promotes Africa-led research, better science communication and stronger ties among scientists in the global South. She also directs the Africa Science Leadership Program.
How the Amazon molly stays genetically healthy
Researchers at the University of Missouri found that the all-female Amazon molly keeps its DNA healthy despite cloning. They show gene conversion and genome comparisons help explain how the species avoided extinction and remained diverse.