Emergent structural and functional properties of hippocampal multi-cellular aggregates

Area of Science:

• Neuroscience
• Biotechnology
• Cellular Biology

Background:

• Traditional 2D neuronal cultures lack crucial brain microenvironment elements.
• 2D cultures are limited in reconstituting sophisticated integrative network properties.
• A need exists for more biofidelic in vitro models of neural networks.

Purpose of the Study:

• To develop and characterize 3D hippocampal neural aggregates using a forced aggregation technique.
• To compare the structural and functional properties of 3D aggregates with traditional 2D cultures.
• To assess the potential of 3D aggregates as building blocks for complex neural network topologies.

Main Methods:

• Generated high-density 3D hippocampal aggregates from rodent embryonic tissue.
• Cultured and analyzed both 3D aggregates and 2D dissociated cultures for 28 days in vitro (DIV).
• Utilized multi-electrode arrays (MEAs) to record spontaneous electrophysiological activity.

Main Results:

• 3D aggregates exhibited enhanced axonal fasciculation and neuronal polarization earlier than 2D cultures.
• Astrocytes in 3D cultures self-organized and developed in vivo-like morphologies.
• 3D networks showed synchronized bursting activity and high burstiness by 28 DIV.
• Dual-aggregate networks became active by 7 DIV, single-aggregate networks by 14 DIV.

Conclusions:

• The 3D microenvironment of hippocampal aggregates supports biofidelic morphological and functional properties.
• Neural aggregates can recapitulate emergent properties of hippocampal networks.
• Aggregates serve as modular building blocks for constructing complex, multi-nodal neural network topologies.