Relationship between individual neuron and network spontaneous activity in developing mouse cortex.

Area of Science:

• Neuroscience
• Developmental Neuroscience
• Computational Neuroscience

Background:

• Spontaneous synchronous activity (SSA) propagates as electrical waves in the central nervous system and is vital for development.
• The mechanisms generating SSA are not fully understood.
• The ventrolateral piriform cortex initiates SSA, unlike the dorsal neocortex.

Purpose of the Study:

• Investigate differing neuronal activity patterns between piriform cortex and dorsal neocortex.
• Determine the basis of SSA initiation in the piriform cortex.
• Explore the role of cell-intrinsic properties in SSA generation.

Main Methods:

• Used Ca(2+) imaging in cultured embryonic mouse cortical slices.
• Applied GABA and glutamate synaptic antagonists.
• Constructed a conductance-based network model with varying intrinsic excitability.

Main Results:

• Piriform cortex showed more asynchronous neuronal activity and coactive cell groups than dorsal cortex.
• Asynchronous activity persisted after synaptic blockade, indicating cell-intrinsic origins.
• Network model simulations showed intrinsic excitability gradients could generate directional waves.

Conclusions:

• Asynchronous neuronal activity and intrinsic excitability differ between cortical regions.
• Cell-intrinsic properties, not solely network connectivity, underlie SSA initiation.
• A gradient of intrinsic excitability in the piriform cortex likely supports SSA generation.