Multi-organoid loop cerebral connectoids exhibit enhanced neuronal network dynamics and sequence-specific entrainment

Area of Science:

• Neuroscience
• Biotechnology
• Systems Biology

Background:

• Neuronal network reconstruction is vital for understanding brain function and disease.
• Current in vitro neuronal culture methods, including organoids, lack the structural complexity for functional dynamics.

Purpose of the Study:

• To develop a novel in vitro platform for constructing complex neuronal networks.
• To investigate the relationship between network size and activity complexity in connected cerebral organoids.

Main Methods:

• Utilized microfluidic devices to connect multiple cerebral organoids into modular networks (loop connectoids).
• Compared network activity patterns in single organoids, reciprocally connected organoids, and three- to four-membered loop connectoids.
• Employed pharmacological and optogenetic stimulation to probe network responses and dynamics.

Main Results:

• Larger connected organoid networks (loop connectoids) exhibited significantly more complex activity, including longer active periods, increased bursting, and richer temporal patterns.
• Network activity in connectoids shifted towards a critical state, indicative of efficient information processing, as more organoids were interconnected.
• Pharmacological challenges demonstrated clear excitatory and inhibitory responses, validating the physiological relevance of the model.
• Optogenetic stimulation revealed the ability to influence spontaneous activity propagation patterns within the network.

Conclusions:

• Modular organoid network tissues (loop connectoids) offer a more physiologically relevant platform for in vitro neural network research.
• Increased network complexity in vitro correlates with enhanced activity dynamics and proximity to a critical state.
• This foundational work paves the way for studying complex neural network functions and developing therapeutic interventions.