Montreal, April 16, 2026 — A research team co-led by Alexandre Dubrac, researcher at the Centre de recherche Azrieli du CHU Sainte‑Justine and professor at the Université e Montréal, reports a major advance in developmental neuroscience with the publication in Cell of the very first detailed atlas of postnatal brain vascular network development. 

The study, to which Mathilde Bizou, co–first author, contributed, was carried out in close collaboration with the laboratory of Dr Nicolas Renier at the Paris Brain Institute. It reveals that brain blood vessels do not simply develop in parallel with neurons. Instead, their growth follows a dynamic, multi‑phase trajectory that varies across brain regions and is tightly linked to the maturation of neural circuits—granting blood vessels an active role in brain construction after birth. 

“We knew that neurons undergo extensive changes after birth, but we understood far less about how blood vessels adapt to these transformations. This atlas finally provides a comprehensive view of this essential dynamic,” explains Mathilde Bizou.

A vital yet still mysterious network 

Although it represents only a small fraction of body weight, the brain alone consumes about 20% of the body’s available oxygen and energy. Meeting this high demand depends on a dense and finely organized network of blood vessels responsible for delivering oxygen and nutrients to neurons. 

At birth, this vascular network is still immature. Yet it is precisely after birth that the brain undergoes major transformations: it grows rapidly, neural circuits are refined, and certain regions specialize based on sensory experience and environmental input. Until now, researchers had very limited tools to track—over time and across the entire brain—how blood vessels adapt to these changes. 

“We had very detailed maps of the adult brain, but far less information on how the vascular network is established after birth,” explains Alexandre Dubrac. “It was a bit like trying to understand how a city functions without access to its road map.” 

A first‑of‑its‑kind atlas of the developing brain 

To address this gap, Nicolas Renier’s team developed a three‑dimensional atlas based on a mouse model, enabling them to track—with unprecedented spatiotemporal precision—the development of the vascular network from birth to adulthood. 

In parallel, Alexandre Dubrac’s team generated and integrated spatiotemporal transcriptomic data, making it possible to link vascular architecture to dynamic molecular programs. By combining these complementary areas of expertise, the study reconstructs the brain’s entire vascular network and analyzes its evolution over time, both structurally and molecularly. 

Photo : This overview shows that at birth, the brain has a rudimentary vascular network, which becomes denser during the first weeks of postnatal life. © Nicolas Renier

Three major phases of development 

One of the study’s main contributions is the identification of three successive phases in postnatal blood vessel development. 

The first phase corresponds to coordinated growth, during which the vascular network and the brain increase in size in a relatively proportional manner. This stage ensures adequate baseline perfusion during the first days of life, comparable to the final months of human fetal development. 

The second phase marks a major shift. During this period, blood vessels grow faster than the brain itself, leading to a marked densification of the vascular network. This stage, which may correspond to early childhood and school age in humans, coincides with so‑called “critical periods” of brain development, when neural circuits are formed, refined, and specialized, particularly in response to sensory activity. 

Finally, a third phase corresponds to a period of stabilization and refinement of the vascular network, which could be associated with adolescence. During this stage, vascular architecture reaches a more mature organization while retaining some capacity for remodeling. 

Vascularization tightly coordinated with neuronal maturation 

The study shows that vascular network development is not uniform throughout the brain. These differences are not explained solely by a general increase in neuronal activity, but rather by the fact that certain brain regions emit specific signals that directly influence whether blood vessel growth continues or stops. By cross‑referencing vascular density maps with gene expression profiles, the team discovered that these signals act as genuine guidance cues for the vascular network, indicating where—and to what extent—it should continue to develop. When these signaling pathways are disrupted, blood vessels lose their guidance, become disorganized, and grow aberrantly. 

These findings demonstrate that the vascular network does not merely passively accompany brain development; it depends closely on communication with neurons. This interaction is particularly critical during the second phase of postnatal development, a period when neuronal activity intensifies and tight coordination between the two systems becomes decisive for the brain’s fine‑scale organization. 

A new tool to better understand certain disorders and diseases 

Beyond its fundamental contribution, this atlas provides an essential starting point for studying various disorders—including autism—as well as certain cerebrovascular diseases that emerge or originate during childhood. 

“Having a reference map of normal development will now allow us to compare what happens when this process is disrupted,” explains Alexandre Dubrac. “We will be able to better understand whether—and how—a mismatch between neuronal development and vascularization contributes to the vulnerability of specific brain regions.” 

Rethinking the brain as a neurovascular system 

The findings of this study invite us to rethink the developing brain as a deeply neurovascular system, in which blood vessels play an active role in brain health, on par with neurons themselves. 

By making a comprehensive and accessible map of the postnatal vascular network available to the scientific community, this Cell publication paves the way for new research into the vascular foundations of brain disorders—and, in the longer term, for new avenues to understand and potentially prevent them from the earliest stages of life.

Photo : Mathilde Bizou (left) and Alexandre Dubrac © CHU Sainte-Justine (Véronique Lavoie)