Model successfully predicts brain structure

The neuronal circuits in the part of your brain called the cerebral cortex are amongst the most complex structures in nature. Nobody knows how they form but it seems likely that self organisation plays a critical role.

Researchers have studied various models of self organisation that might explain how these circuits form but have come up against a problme. None of the models make experimentally testable predictions so ther is no way of choosing between them. Until now.

Matthias Kaschube at the Max Planck Institute for Dynamics and Self-Organization in Germany and a few pals have developed a model of self organisation within the brain that makes a specific prediction about a type of feature in the visual cortex called a pinwheel. These are topological defects in the arrangement of neurons that can easily be spotted in the brain.

Nobody is quite sure how pinwheels form but Kaschube says that in his model they form natrually if thenetwork allows for lang range interactiosn between neurons (which is what appears ot happen int eh visual cortex).

Their prediction is this: that the average density of pinwheels within the brain should be equal to pi, 3.141….

That’s pretty specific. They say there is not enough data to confirm their prediction but that a prelimanru study indicates that the value is somewhere close to 3, which is promising.

This is the first experimentally testable prediction ever made about brain structure, sys the group.
It looks like good work but I’d wanna know about the uniqueness of this solution. Can they show that no other model predicts a pinwheel density equal to pi?

Ref: arxiv.org/abs/0801.3651: Self-Organization and the Selection of Pinwheel Density in Visual Cortical Development