Reliable Sequential Activation of Neural Assemblies by Single Pyramidal Cells in a Three-Layered Cortex

Area of Science:

• Neuroscience
• Computational Neuroscience

Background:

• Recent research highlights the significant impact of single neurons on neural circuits and behavior.
• Understanding the precise influence of individual neurons within cortical networks is crucial for deciphering neural computation.

Purpose of the Study:

• To investigate the influence of single pyramidal neurons on surrounding cortical circuits.
• To characterize the spatiotemporal dynamics of activity evoked by single neuron activation.

Main Methods:

• Utilized a simplified cortical model to examine the effects of single pyramidal neuron activation.
• Recorded postsynaptic potentials and firing activity in neighboring excitatory and inhibitory neurons.
• Analyzed the specificity and propagation of evoked activity patterns.

Main Results:

• Single pyramidal neuron activation reliably triggered sequential firing in tens of local neurons.
• Evoked activity exhibited precise, delayed, polysynaptic subthreshold potentials, indicating network propagation.
• Activity patterns were specific to the originating neuron and propagated over hundreds of micrometers within 200 ms.
• Simultaneous activation of pyramidal cell pairs demonstrated balanced control, preventing runaway excitation.

Conclusions:

• Individual cortical pyramidal neurons can initiate reliable, propagating postsynaptic activity.
• This single-neuron-driven activity generates rapidly evolving, non-random firing sequences.
• These findings offer insights into neural replay mechanisms observed in other brain regions and circuits.