The Brain Architecture Project is a collaborative effort aimed at creating an integrated resource containing knowledge about nervous system architecture in multiple species, with extensive whole-brain light microscopic data sets available for Mouse and Marmoset as well as for other species including Zebra Finch and Human.

What is architecture? In its traditional setting of buildings, architecture is the shaping of space for human use. In the case of nervous systems, “architecture” may be defined as the collection of structural elements that enable behaviors, both intrinsic and stimulus driven.

This architecture may be studied at different levels of organization: intracellular networks (gene regulatory networks as well as protein interaction networks), intra-cellular neural networks (local microcircuits, mesocircuits between anatomical regions) as well as organization on a larger scale of organ systems in the body (neuroendocrine and peripheral nervous systems). Shaped by the evolutionary process, nervous system architecture enables behaviors important for survival and adaptation to the environment.

Our knowledge about nervous system architecture is fragmented and incomplete. For even the best studied rodent species, we only have a partial knowledge about brain connectivity, and for other species the knowledge is even more limited. The goal of the Brain Architecture Project is to assemble and analyze data sets pertaining to cytoarchitecture, cell-type composition, neuronal morphology and mesoscale connectivity of multiple species, currently with a primary focus on the Mouse and the Marmoset.

The Brain Architecture Project involves several laboratories from institutions spanning multiple countries. Three of the main data sets represented on this data portal are (i) Mouse: mesoscale connectivity atlas (wildtype), (ii) Mouse: Cell-type specific data, including spatial density, connectivity, morphology and single-nucleus RNA sequencing data, and (iii) Marmoset: mesoscale connectivity atlas (wildtype).

The Mouse Brain Architecture Project (MBAP) (wildtype connectivity) is a high throughput experimental project, the goal of which is to systematically do injection-based tractography in whole mouse brains, on a grid of injections that cover the whole brain. The motivation for this project can be found in the position paper Bohland et al. (2009).