A new tracking microscope system developed by the Leifer lab at Princeton uses light to manipulate and monitor neural dynamics from a worm as it crawls. This system helps understand how patterns of brain activity generate behavior. See Shipley et al 2014 available for free at journal.frontiersin.org/Journal/10.3389/fncir.2014.00028/full
The nematode C. elegans is shown crawling in the microscope. The worm has been genetically engineered such that a specific neuron, AVA, fluoresces green when that neuron becomes active. Another set of neurons, the touch neurons, have been engineered to be excitable by blue light. At time t=0 blue light shines on a touch neuron ALM and the worm feels like it is being touched. The worm reverses and neuron AVA becomes active during the reversal.