Collective dynamics of neuronal activities in various modular networks

Area of Science:

• Neuroscience
• Biophysics
• Materials Science

Background:

• Brain networks exhibit modularity, crucial for both structure and function.
• The relationship between structural modularity and functional activity in brain networks remains underexplored.

Purpose of the Study:

• To investigate the association between the structure and function of modular brain networks.
• To analyze how neuronal activity is affected by varying degrees of modular connectivity in engineered cortical networks.

Main Methods:

• Constructed modular cortical networks (4, 3, or 2 modules) in vitro using polydimethylsiloxane (PDMS) microstructures directly on a multi-electrode array (MEA).
• Recorded and analyzed spontaneous neuronal activities, including spike amplitudes, network bursts, and spike propagation properties.
• Stimulated electrodes to observe network responses (bursts vs. spikes) based on modular topology.

Main Results:

• Network modularity and connectivity strength varied, with the 4-module network showing the highest modular connectivity.
• Neuronal activity characteristics, such as network bursts and spike propagation, differed significantly across network topologies.
• Electrical stimulation elicited distinct responses: bursts in the 4-module network and spikes in the 2- and 3-module networks.

Conclusions:

• The study demonstrates a clear link between the structural modularity of engineered brain networks and their functional neuronal activity.
• The direct fabrication technique on MEAs enables precise construction of modular networks for detailed in vitro studies.
• This approach facilitates systematic investigation into the dynamics of modular neuronal networks and their structure-function relationships.