Figure 1.

A system for delivering pulsed ultrasound to C. elegans nematodes. A, Schematic side view of the setup, showing a single wild-type adult hermaphrodite crawling on the surface of agar slab, tracked by a digital video camera, and maintained within the field of view by a copper sulfate boundary. A piezoelectric ultrasound transducer (10 MHz carrier frequency, line-focused) is coupled directly to the bottom of the agar slab by a column of degassed water. B, Simulation of the distribution of radiation force expected from the line-focused 10 MHz ultrasound transducer (see Materials and Methods). Animals were stimulated only during forward movement, as they entered the zone corresponding to the highest expected pressure. C, Schematic of a typical stimulus consisting of ultrasound pulses delivered at PRF of 1 kHz for a total duration of 200 ms at 50% duty cycle. In this study, we systematically varied the applied pressure, pulse duration, PRF, and duty cycle.