Synaptic signaling in an active central network only moderately changes passive membrane properties

Area of Science:

• Neuroscience
• Computational Neuroscience
• Cellular Electrophysiology

Background:

• Mammalian central neurons exhibit dynamic changes in membrane resistance during network activity.
• Synaptic events can significantly alter neuronal integration properties.

Purpose of the Study:

• To quantify the impact of synaptic signaling on passive membrane properties during network activity.
• To investigate how synaptic events influence neuronal integration in the mammalian central nervous system.

Main Methods:

• Utilized an isolated neonatal rat spinal cord preparation.
• Measured changes in input resistance (Rin) and charging time constant (tauin) during fictive locomotor activity.
• Analyzed the conductance of individual synaptic signals relative to input conductance (Gin).

Main Results:

• Synaptic signaling during network activity caused an average reduction of 35% in input resistance (Rin) and charging time constant (tauin).
• Individual synaptic signals frequently induced peak conductance exceeding the baseline input conductance (Gin).
• A discrepancy exists between average synaptic conductance and the large conductance of individual synaptic events.

Conclusions:

• Synaptic signaling modulates neuronal integration properties during network activity.
• Individual presynaptic neurons exert a substantial yet transient influence on postsynaptic neuron integration.
• The interplay between moderate average and large individual synaptic conductances shapes neuronal integration.