"In a way, we treated small regions of the brain like cognitive units: not as individual cells but as groups of cells," said Gustavo Deco, PhD, professor and head of the Computational Neuroscience Group in Barcelona. "The activity of these cognitive units sends out excitatory signals to the other units through anatomical connections. This makes the connected units more or less likely to synchronize their signals."
Based on data from brain scans, researchers assembled 66 cognitive units in each hemisphere, and interconnected them in anatomical patterns similar to the connections present in the brain.
Scientists set up the model so that the individual units went through the signaling process at random low frequencies that had previously been observed in brain cells in culture and in recordings of resting brain activity.
Next, researchers let the model run, slowly changing the coupling, or the strength of the connections between units. At a specific coupling value, the interconnections between units sending impulses soon began to create coordinated patterns of activity.
"Even though we started the cognitive units with random low activity levels, the connections allowed the units to synchronize," Deco said. "The spatial pattern of synchronization that we eventually observed approximates very wellabout 70 percentto the patterns we see in scans of resting human brains."
Using the model to simulate 20 minutes of human brain activity took a cluster of powerful computers 26 hours. But researchers were able to simplify the mathematics to make it possible to run the model on a typical computer.
"This simpler whole brain model allows us to test a number of different hypotheses on how the structural connections generate dynamics of brain function at res
|Contact: Michael C. Purdy|
Washington University School of Medicine