Nonlinear interneuronal properties underlie integrative flexibility in a lobster disynaptic sensorimotor pathway

Area of Science:

• Neuroscience
• Computational Neuroscience
• Systems Neuroscience

Background:

• The lobster stomatogastric nervous system provides a model for understanding sensorimotor integration.
• A specific pathway involves the anterior gastric receptor (AGR) neuron, commissural gastric (CG) interneurons, and gastric medial (GM) motoneurons.

Purpose of the Study:

• To investigate the flexibility of information processing within a seemingly simple, hard-wired disynaptic sensorimotor pathway.
• To determine the cellular mechanisms underlying the variable output responses of GM motoneurons to AGR input.

Main Methods:

• Electrophysiological recordings from in vitro preparations of the lobster stomatogastric nervous system.
• Analysis of synaptic pathways and neuronal responses, focusing on the role of CG interneurons.

Main Results:

• The AGR-CG-GM pathway exhibits diverse GM output patterns, including excitation, prolonged responses, and induced bursting activity.
• Flexibility arises from intrinsic properties of the CG interneuron, specifically its ability to generate regenerative plateau and oscillatory depolarizations.
• The sign of the motor response (excitation or inactivation) can switch based on AGR input levels, mediated by CG's firing properties.

Conclusions:

• Even hard-wired neuronal pathways can exhibit significant flexibility in sensorimotor integration.
• Intrinsic properties of an intercalated interneuron (CG) are crucial for modulating information processing and input-output relationships.
• This cellular flexibility allows for adaptable motor control within a fixed neural circuit.