Tao mapping

The long-distance network of the Macaque monkey brain, spanning the cortex, thalamus, and basal ganglia,
showing 6,602 long-distance connections between 383 brain regions.
from: Dharmendra S. Modha and Raghavendra Singh,
"Network architecture of the long-distance pathways in the macaque brain", PNAS vol. 107 no. 30, 2010

Abstract

Understanding the network structure of white matter communication pathways is essential for unraveling the mysteries of the brain’s function, organization, and evolution. To this end, we derive a unique network incorporating 410 anatomical tracing studies of the macaque brain from the Collation of Connectivity data on the Macaque brain (CoCoMac) neuroinformatic database. Our network consists of 383 hierarchically organized regions spanning cortex, thalamus, and basal ganglia; models the presence of 6,602 directed long-distance connections; is three times larger than any previously derived brain network; and contains subnetworks corresponding to classic corticocortical, corticosubcortical, and subcortico-subcortical fiber systems. We found that the empirical degree distribution of the network is consistent with the hypothesis of the maximum entropy exponential distribution and discovered two remarkable bridges between the brain’s structure and function via networktheoretical analysis. First, prefrontal cortex contains a disproportionate share of topologically central regions. Second, there exists a tightly integrated core circuit, spanning parts of premotor cortex, prefrontal cortex, temporal lobe, parietal lobe, thalamus, basal ganglia, cingulate cortex, insula, and visual cortex, that includes much of the task-positive and task-negative networks and might play a special role in higher cognition and consciousness.

“We have successfully uncovered and mapped the most comprehensive long-distance network of the Macaque monkey brain, which is essential for understanding the brain’s behavior, complexity, dynamics and computation,” Dr. Modha says. “We can now gain unprecedented insight into how information travels and is processed across the brain.

“We have collated a comprehensive, consistent, concise, coherent, and colossal network spanning the entire brain and grounded in anatomical tracing studies that is a stepping stone to both fundamental and applied research in neuroscience and cognitive computing.”

They focused on the long-distance network of 383 brain regions and 6,602 long-distance brain connections that travel through the brain’s white matter, which are like the “interstate highways” between far-flung brain regions, he explained, while short-distance gray matter connections (based on neurons) constitute “local roads” within a brain region and its sub-structures.

Their research builds upon a publicly available database called Collation of Connectivity data on the Macaque brain (CoCoMac), which compiles anatomical tracing data from over 400 scientific reports from neuroanatomists published over the last half-century.

“We studied four times the number of brain regions and have compiled nearly three times the number of connections when compared to the largest previous endeavor,” he pointed out. “Our data may open up entirely new ways of analyzing, understanding, and, eventually, imitating the network architecture of the brain, which according to Marian C. Diamond and Arnold B. Scheibel is “the most complex mass of protoplasm on earth—perhaps even in our galaxy.”

The brain network they found contains a “tightly integrated core that might be at the heart of higher cognition and even consciousness … and may be a key to the age-old question of how the mind arises from the brain.” The core spans parts of premotor cortex, prefrontal cortex, temporal lobe, parietal lobe, thalamus, basal ganglia, cingulate cortex, insula, and visual cortex.

Innermost core for the undirected version of our network. The innermost core is a central subnetwork that is far more tightly integrated than the overall network. Information likely spreads more swiftly within the innermost core than through the overall network, the overall network communicates with itself mainly through the innermost core, and the innermost core contains major components of the task-positive and task-negative networks derived via functional imaging research.