The neural basis of catalepsy in the stick insect

✍ Scribed by R. B. Driesang; A. Büschges

• Publisher: Springer
• Year: 1993
• Tongue: English
• Weight: 983 KB
• Volume: 173
• Category: Article
• ISSN: 0340-7594
• DOI: 10.1007/bf00193517

✦ Synopsis

The known nonlinearities of the femur-tibia control loop of the stick insect Carausius morosus (enabling the system to produce catalepsy) are already present in the nonspiking interneuron E4: (1) The decay of depolarizations in interneuron E4 following slow elongation movements of the femoral chordotonal organ apodeme could be described by a single exponential function, whereas the decay following faster movements had to be characterized by a double exponential function.

(2) Each of the two corresponding time constants was independent of stimulus velocity. (3) The relative contribution of each function to the total amount of depolarization changed with stimulus velocity. (4) The characteristics described in (1)-(3) were also found in the slow extensor tibiae motoneuron. (5) Single electrode voltage clamp studies on interneuron E4 indicated that no voltage dependent membrane properties were involved in the generation of the observed time course of decay. Thus, we can trace back a certain behavior (catalepsy) to the properties of an identified, nonspiking interneuron.