Neural networks study reveals hierarchical structure

July 13, 2011

Researchers at Tel Aviv University’s School of Electrical Engineering have developed a new kind of a lab-on-a-chip platform that may help neuroscientists understand one of the deepest mysteries of our brain: how neuronal networks communicate and work together.

Using network engineering techniques, the scientists cultured different sized networks of neuronal clusters. Once they looked at these groups, they found rich and surprising behaviors that could not be predicted from what scientists know about single neurons.

The researchers were able to measure patterns from nerve activity at nodes where a number of nerves converged into networks. What they detected appeared to show that neural networks have a hierarchical structure — large networks are composed of smaller sub-networks. This observation, and a unique setup using electrodes and living nerves, allowed them to create hierarchical networks in a dish.

The brain’s circuits work like codes, the researchers said. The researchers were able to see the patterns in the networks and simplify them, and control connectivity between cells to see how the neuronal network responds to various chemicals and conditions. One theory proposed by the researchers is that the human brain stores memories like a holograph of an image: small neural networks contain information about the whole brain, but only at a very low resolution.

The researchers showed that clusters of as few as 40 cells can serve as a minimal but sufficient functional network. This cluster is capable of sustaining neural network activity and communicating with other clusters.

Ref.: Mark Shein Idelson, Eshel Ben-Jacob, Yael Hanein, Innate Synchronous Oscillations in Freely-Organized Small Neuronal Circuits, PLoS ONE, 2010; 5 (12): e14443 [DOI: 10.1371/journal.pone.0014443]