Wired together, change together: Spike timing modifies transmission in converging assemblies

Area of Science:

• Neuroscience
• Synaptic Plasticity
• Learning and Memory

Background:

• Neuronal spike timing is critical for synaptic plasticity, learning, and memory.
• The influence of spike timing on neuronal connectivity in vivo remains largely unexplored.

Purpose of the Study:

• To investigate the impact of precise spike timing on neuronal connectivity in the intact brain.
• To explore the role of cell assembly spike timing in synaptic plasticity.

Main Methods:

• Utilized closed-loop optogenetic stimulation in the CA1 region of freely moving mice.
• Generated specific spike patterns between presynaptic pyramidal cells (PYRs) and postsynaptic parvalbumin (PV)-immunoreactive cells.

Main Results:

• Observed spike transmission changes across all presynaptic PYRs connected to a single postsynaptic PV cell.
• Demonstrated that the precise timing of both presynaptic and postsynaptic cell spikes influences these transmission changes.
• Revealed that the collective spike timing of a cell assembly significantly impacts effective connectivity.

Conclusions:

• Identified a novel plasticity mechanism where cell assembly spike timing is more influential than individual cell pair timing.
• Highlights the importance of coordinated neuronal activity in shaping effective connectivity for learning and memory.