On Jul. 16, 2009, the National Institutes of Health Blueprint for Neuroscience Research announced it was  launching a $30 million project that used cutting-edge brain imaging technologies to map the circuitry of the healthy adult human brain. By systematically collecting brain imaging data from hundreds of subjects, the Human Connectome Project (HCP) yielded insight into how brain connections underlie brain function, and opened up new lines of inquiry for human neuroscience.

Investigators have been invited to submit detailed proposals to carry out the HCP, which will be funded at up to $6 million per year for five years. The HCP is the first of three Blueprint Grand Challenges, projects that address major questions and issues in neuroscience research.

The Blueprint Grand Challenges are intended to promote major leaps in the understanding of brain function, and in approaches for treating brain disorders. The three Blueprint Grand Challenges to be launched in 2009 and 2010 address:

• The connectivity of the adult, human brain
• Targeted drug development for neurological diseases
• The neural basis of chronic pain disorders

Scientists have studied the relationship between the structure and function of the human brain since the 1800s. Some parts of the brain serve basic functions such as movement, sensation, emotion, learning and memory. Others are more important for uniquely human functions such as abstract thinking. The connections between brain regions are important for shaping and coordinating these functions, but scientists know little about how different parts of the human brain connect.

The complexity of the brain and a lack of adequate imaging technology have hampered past research on human brain connectivity. The brain is estimated to contain more than 100 billion neurons that form trillions of connections with each other. Neurons can connect across distant regions of the brain by extending long, slender projections called axons – but the trajectories that axons take within the human brain are almost entirely uncharted.

In the HCP, researchers will optimize and combine state-of-the-art brain imaging technologies to probe axonal pathways and other brain connections. In recent years, sophisticated versions of magnetic resonance imaging (MRI) have emerged that are capable of looking beyond the brain’s gross anatomy to find functional connections. Functional MRI (fMRI), for example, uses changes in blood flow and oxygen consumption within the brain as markers for neuronal activity, and can highlight the brain circuits that become active during different behaviors.

Since this is the first time that researchers will combine these brain imaging technologies to systematically map the brain’s connections, the HCP will support development of new data models, informatics and analytic tools to help researchers make the most of the data. Funds will be provided for building an on-line platform to disseminate HCP data and tools, and for engaging and educating the research community about how to use these data and tools.