Modeling Brain Wiring in Whisker Barrels


It’s been estimated that a human brain contains 100 trillion connections between some 100 billion neurons. How is such a monstrous wiring job accomplished? One possibility is that there is a complete wiring plan encoded in our genes. But another explanation is that the initial genetic plans are simple, and complexity arises from relatively simple interactions between growing cells.

Now a new computer modeling study of rats and mice shows that a part of the rodent brain that corresponds to their whiskers can develop from simple interactions. The work by neuroscientists Sebastian James and Stuart Wilson at the University of Sheffield, U.K. and Leah Krubitzer at UC Davis was published Sept. 29 in eLife.

Whisker barrels are cylindrical clusters of cells in the brains of rats and mice that match the arrangement of whiskers on the animal’s face. That makes them ideal for studying brain wiring.

Simulating guidance fields

Connections between neurons could be guided by gradients of proteins, called guidance fields. The idea is that the cell would extend itself along a gradient until it meets another cell with which to connect.

The researchers used computer simulations to study how neurons could organize themselves into a whisker barrel using a limited number of guidance fields. They found that they could recreate a whisker barrel with just two guidance fields, as well as some simple rules, such as that neurons from different whiskers would compete for space. This forced the cells into whisker-specific clusters.

“This model describes a simple way that specific structures can be copied across the central nervous system,” the authors wrote.

Understanding the wiring of the barrel complex could help us understand normal brain development and how it can go wrong in some neurodevelopmental disorders. It could also help us understand how patients can recover from stroke or traumatic brain injury.

This article originally appeared in egghead About Research at UC Davis