Figure 4. Diverse selectivity in the neurons of the femoral chordotonal organ (fCO).

(A) Intracellular recordings can be made from individual chordotonal neurons of the ventral cluster in the hindleg of the locust femur. Neurons in the fCO are typically stimulated by movements of the receptor apodeme, and recordings are targeted to axons as they enter the VNC. These recordings have shown diversity in selectivity among individual neurons in the same organ.

(B) This example shows a phasic neuron, which exhibits transient responses to tibial movement, as well as a tonic neuron, which exhibits sustained firing [adapted from 91].

(C) Hysteresis of tibial position coding in a femoral chordotonal neuron. This neuron fires at higher rates when the preceding movement was flexion of the femur/tibia joint [adapted from 92]. Arrows indicate direction of preceding movements.