Updated on 17 October 2013
Dr Wang's group used a combination of genetic engineering and fluorescent tags delivered by viruses to color-code four different kinds of neurons and map their connections.
Earlier work by Dr Wang and others had found that all of the 100 to 200 sensors associated with a single whisker project their axons to a large structure representing that whisker in the brain. Each whisker has its own neural representation structure.
"People have thought that within the large whisker-representing structure, there will be finer-scale, labeled lines," Dr Wang said. "In other words, different touch sensors would send information through separate parallel pathways, into that large structure. But surprisingly, we did not find such organized pathways. Instead, we found a completely unorganized mosaic pattern of connections within the large structure. Information from different sensors is intermixed already at the first relay station inside the brain," Dr Wang added.
Dr Wang said the next step will be to stimulate the labeled circuits in different ways to see how impulses travel the network. "We want to figure out the exact functions and signals transmitted by different sensors during natural tactile behaviors and determine their exact roles on the perception of textures," she said.
The research was supported by grants from the National Institutes of Health, the Swiss National Foundation, Kanton Basel-Stadt, and ERC Advanced Grant, and the Novartis Research Foundation.