LCD projector controls worm’s brain, muscle

LCD projector controls worm’s brain, muscle

Using inexpensive components from ordinary LCD projectors, Hang Lu, an associate professor at the Georgia Institute of Technology’s School of Chemical & Biomolecular Engineering, and graduate students Jeffrey Stirman and Matthew Crane have developed a tool that controls the brains and muscles of tiny, free-moving Caenorhabditis elegans worms.

Developed with support from the National Institutes of Health and the Alfred P. Sloan Foundation, the tool can also be used to evaluate responses to chemical, thermal, and visual stimuli, and researchers can also use it to study a variety of neurons and muscles in other small animals, such as fruit fly larvae.

“Experiments with this illumination system yield quantitative behavior data that cannot be obtained by manual touch assays, laser cell ablation, or genetic manipulation of neurotransmitters,” said Lu. For their first experiment, the researchers illuminated the head of a worm at regular intervals while the animal moved forward. This produced a coiling effect in the head and caused the worm to crawl in a triangular pattern (see figure ).

Illuminated using the components of an LCD projector, reserchers were able to directly control the motion of a Caenorhabditis elegans worm.

The illumination system’s modified off-the-shelf LCD projector is used to cast a multicolor pattern of light onto an animal. The projector’s independent red, green, and blue channels let researchers activate neuron and muscle cells sensitive to specific colors, while simultaneously silencing others. The cells are genetically engineered with light-sensitive microbial proteins so researchers can switch them on and off.

By connecting the illumination system to a microscope and combining it with video tracking, the researchers can keep the light on the intended anatomical position, as well as track and record the animal’s behavior. When the animal moves, the light’s location can be updated in less than 40 ms, as can its intensity and color.Until now, optogenetics a mix of optical and genetic techniques could only be used with larger animals, which is a disadvantage in many areas of research. For more information, contact Hang Lu at hang.lu@chbe.gatech.edu.

Richard Comerford