Network synchronization in hippocampal neurons.

Area of Science:

• Neuroscience
• Computational Neuroscience
• Systems Neuroscience

Background:

• Oscillatory activity is fundamental to dynamic neuronal networks.
• Existing models often propose specialized pacemaking neurons to generate network periodicity.

Purpose of the Study:

• To investigate the spontaneous emergence of synchronized periodic bursting in cultured rat hippocampal and cortical neurons.
• To understand the role of intrinsic neuronal properties and network connectivity in generating network oscillations.

Main Methods:

• Cultured dissociated neurons from rat hippocampus and cortex were used.
• Electrophysiological recordings were performed to assess neuronal activity and oscillations.
• Neuronal connectivity was gradually altered to observe changes in network dynamics.

Main Results:

• Approximately 60% of active neurons exhibited self-sustained intrinsic oscillations.
• Intrinsic oscillation frequency and tendency were linked to neuronal excitability and persistent sodium leak currents.
• Network connectivity led to emergent synchrony, with oscillators converging to a common frequency and reducing phase shifts, culminating in zero-lag synchronous bursts.
• The network burst frequency matched the average of individual neuron intrinsic frequencies.

Conclusions:

• Intrinsic single-neuron excitability plays a crucial role in driving network activity and dynamics.
• Emergent order and synchronized periodic bursting arise from the entrainment of independent rhythmic neuronal units.
• This study provides insights into the fundamental mechanisms underlying developing neural circuit dynamics.