Locomotion models

Effects on the locomotion of nematodes have been linked to a deterioration of the neural network which can be evaluated based on several criteria, such as head thrash, body bend frequency, and basic movements. Each exposed nematode is transferred to a plate containing 60 μL of K medium on the top of the agar. After a recovery period of 1 min, the number of head trashes is counted for 1 min. A head trash is defined as a change in the direction of bending in the body.

To test the body bend frequency, nematodes are collected in a second plate, and then the number of times that the body bends in a period of 20 s is recorded. The bend of the body is observed as a change in direction of the upper pharynx along the Y axis, assuming that the nematodes are moved along the X axis. To test the basic movements, the number of sinusoidal forward movements is counted at an interval of 20 s. Locomotion behavior of control and treated nematodes should be analyzed simultaneously to avoid possible influences of the light-darkness cycle. Alternatively, immobility is determined by counting the number of immobile worms, usually registering a response when touched by platinum wire.