Fig. 1. (A) Setup for ascertaining the inhibitory effect of accessory neurons on stretch-activated responses of TSR. An en passant suction electrode is used for antidromic stimulation of accessory neurons and for extracellular recording of stretch-activated responses which, at the same time, show the presence or absence of an inhibitory effect of putative accessory neurons. By pulling the tergite of the sixth thoracic segment, the receptor muscle of TSR-4 is stretched and stretch-activated responses occur as shown (arrow) in a representative trace composed of rapidly and slowly adapting responses. (B) Arrangement of electrodes for recording junctional potentials from two extensor muscles. Experiments were carried out to determine which muscle is innervated by neuron #1. To record junctional potentials of DEM1, the recording (R) and stimulating (S) electrodes were R1, R2, R4 and S. For DEM2, R1, R3, R4 and S were used. Each experiment was conducted in a separate animal. ANT, anterior; AX, axon of the receptor cell of the thoracic stretch receptor; D, dorsal; DEM1, medial deep extensor muscle; DEM2, lateral deep extensor muscle; EXT, extracellular recording; INT, intracellular recording; N3, third segmental nerve; npm, nerve to deep extensor muscle; nsm, nerve to superficial extensor muscle; POST, posterior; RC1, receptor cell of rapidly adapting stretch receptor; RC2, receptor cell of slowly adapting stretch receptor; RM, receptor muscle; ST, stretch stimulus; TG, thoracic ganglion; TS, thoracic segment; TSR, thoracic stretch receptor; V, ventral.

Return to article