(Showing your love with worms)
Looking for a unique way to display your love to that special person in your life? Aravinthan Samuel and his group of researchers at the Harvard University Department of Physics and Brain Science may just have the solution to your quest; they have managed to direct Caenorhabditis elegans, a tiny worm, to wiggle around forming perfect hearts, check-out the cool video. Prof. Samuels research, which was published in this weeks Journal of Neuroscience, is not meant to take a bite out of Hallmarks valentine card market; rather it is an attempt to understand how the nervous system converts sensory perception into movement. Humans have more than a billion neurons, which makes understanding what is going on in our brains rather complicated, C. elegans only has 302 neurons making it an ideal research subject for studies such as this one.
C. elegans colonies are grown in Petri dishes containing agar. Within seconds of turning on an electric field nearly every worm on the agar surface will make its way to the negative pole. This has been known since 1978. However this week for the first time it has been reported that the 1mm worms dont head straight to the negative pole, instead they crawl in an undulating snakelike fashion following the force lines of the electric field. The direction of C. elegans movement can be changed by altering the field. While a steady rotation will cause the poor nematodes to snake around in perfect circles, a more skillful electric field operator is be able to control the worms like an Etch A Sketch.
Prof. Samuel labeled specific sensory neurons with cameleon, a protein that measures the calcium concentration in cells. In this way he was able to establish which sensory neurons are sensitive to the direction of the electric field, and which interneurnol circuits are responsible for the decision to use either a turn or a reversal to reorientate in response to a change in the electric field. This study is a significant step in understanding how the nervous system transfers sensory input into motor output.
C. elegans moving along the force lines of an electric field
(Courtesy: A. Samuel).