Researchers from the University of Oxford have revealed how brain development creates the foundation for both shared and sex-specific neural circuits. The findings help explain how differences in behaviour emerge within the same brain structure.

Two companion studies, published in Cell Genomics, examined how neurons form and organise during development. Together, the studies show that the brain retains a molecular record of how it was built during early development.

Therefore, the research provides a new framework for understanding how neural diversity arises and how brain architecture evolves.

🔬 Scientists Build First High-Resolution Brain Atlas

The research team created the first high-resolution molecular atlas of the adult brain of the fruit fly (Drosophila melanogaster). This atlas allowed scientists to study the genetic and molecular characteristics of individual neurons in unprecedented detail.

To build the atlas, researchers combined several single-cell RNA sequencing datasets. As a result, they achieved tenfold coverage of the fly’s central brain and captured transcriptional information for nearly every neuron.

This detailed mapping provided scientists with a comprehensive view of how neurons develop and differentiate over time.

🧬 Neurons Retain a Record of Their Development

One of the study’s key discoveries was that neurons in the adult brain retain molecular signatures of their developmental origins. These molecular patterns reflect the lineage and timing of each neuron’s formation.

Moreover, researchers found that neuronal diversity is far greater than previously believed. Some neuron types appear only once in each hemisphere of the brain.

The team also concluded that molecular identity and anatomical structure together define neuron types. Consequently, both factors must be considered to understand how brain circuits form.

⚧️ Sex Differences Arise From Shared Neural Templates

A companion study explored how male and female brains develop behavioural differences.

Instead of creating completely separate neural circuits, the research showed that male and female brains use the same developmental templates. However, they modify these templates in different ways.

The scientists discovered that sex differences arise through selective survival of neurons within shared lineages. Female-biased neurons tend to appear earlier during development, whereas male-biased neurons emerge later.

Therefore, sex differences result from changes in timing and survival of neurons rather than entirely new neural wiring.

Researchers say this mechanism allows evolution to create new behaviours without rebuilding the brain’s architecture.

🌍 Findings Offer New Insights Into Brain Organisation

The discoveries provide valuable insight into how complex brains develop and function.

By linking molecular data with anatomical structure, the atlas offers new tools for studying neural systems. Scientists can now explore how developmental processes shape behaviour and neural networks.

In addition, the research provides important parameters for computational neuroscience and brain modelling.

The Oxford team has also released an interactive online resource that allows researchers to explore the brain atlas and examine neuronal data in detail.

Overall, the findings highlight how simple developmental rules can generate the enormous diversity seen in brain circuits and behaviour.