Can worms unlock the secrets of our mind?

Mind worms The different foraging strategies reflect different activity of a neural circuit, highlighted here by expressing a protein that fluoreces green in the neurons.

MRC Laboratory of Molecular Biology, Cambridge; University of Cambridge

A tiny transparent worm that lives in rotting fruit is helping to unravel how the brain works. Caenorhabditis elegans, C. elegans for short, has a nervous system, gut, muscle, and other tissues similar to humans. The worm reaches maturity in a few days, has 300 offspring and is transparent, making it an ideal research tool.

‘C. elegans is the best understood multicellular organism on the planet, but we are only beginning to understand how its nervous system generates behaviour,’ says Bill Schafer of the Medical Research Council Laboratory (MRC) of Molecular Biology, Cambridge.

Human brains have 100 billion neurones; C. elegans has just 302. This makes it far easier to map the pathways that link neurone stimulation to action in the worm. ‘It is a bit like using a Trabant to understand a Porsche,’ explains Mario de Bono also of the MRC Laboratory, Cambridge. ‘If we can understand how the worm’s brain computes behaviour, we can apply this knowledge to the more sophisticated human brain.’

Specific neurones in the worm can be activated or inhibited by adding ion channels that respond to flashes of light. ‘This enables us to directly link specific behaviours to particular neurons, and engineer worms to exhibit certain behaviours in response to a light pulse,’ explains Mario.