Interaction and synchronization between two abdominal motor systems in crayfish

Area of Science:

• Neuroscience
• Crustacean neurobiology
• Motor control

Background:

• The swimmeret and abdominal positioning systems in crayfish are crucial for locomotion and posture.
• Understanding the neural coordination between these systems provides insights into complex motor pattern generation.

Purpose of the Study:

• To investigate the spontaneous coordination between the crayfish swimmeret and abdominal positioning motor systems.
• To determine the effects of oxotremorine on the coordination and rhythmicity of these motor systems.

Main Methods:

• Extracellular and intracellular recordings from an isolated thoraco-abdominal crayfish preparation.
• Electrophysiological analysis of motor neuron activity and rhythmic bursting patterns.
• Pharmacological manipulation using bath application and injection of oxotremorine.

Main Results:

• Spontaneous coordination between swimmeret and abdominal positioning systems was observed, including in-phase bursting and inhibition of swimmeret rhythm.
• Depolarization of abdominal interneurons induced these coordination patterns.
• Oxotremorine dose-dependently increased swimmeret rhythm frequency and induced rhythmic activity in the abdominal positioning system.
• Oxotremorine at higher concentrations induced complex interactions between the two systems, including cycle-by-cycle and slow coordination.

Conclusions:

• The swimmeret and abdominal positioning systems exhibit inherent coordination capabilities.
• Oxotremorine acts as a modulator, influencing the frequency and coordination of these motor systems in a dose-dependent manner.
• Findings in isolated preparations are comparable to rhythmic abdominal movements observed in intact crayfish, suggesting conserved neural mechanisms.