Global structure, robustness, and modulation of neuronal models.

Area of Science:

• Computational Neuroscience
• Neurophysiology
• Systems Neuroscience

Background:

• Neurons display stable electrical properties amidst fluctuating conditions.
• Neuromodulators significantly influence neuronal function and activity patterns.

Purpose of the Study:

• To analyze the global structure of a conductance-based model neuron.
• To understand the relationship between maximal conductance parameters and neural activity patterns.
• To investigate the dual robustness and sensitivity of neuronal electrical characteristics.

Main Methods:

• Global analysis of a conductance-based model neuron.
• Systematic variation of maximal conductance parameters.
• Characterization of neural activity patterns (silent, tonically firing, bursting).
• Verification using dynamic clamp recordings in stomatogastric ganglion neurons.

Main Results:

• Identified directions in conductance space where neural activity patterns remain stable.
• Demonstrated that small concurrent changes in conductances can alter activity patterns.
• Showed that neuromodulators targeting sensitive conductances have potent, state-dependent effects.

Conclusions:

• Neuronal electrical activity is characterized by both robustness and sensitivity.
• The structure of conductance space dictates how neuromodulators affect neuronal function.
• Neuromodulators can indirectly influence neuronal activity by altering the effects of other modulators.