Inhibition enhances memory capacity: optimal feedback, transient replay and oscillations

Area of Science:

• Neuroscience
• Computational Neuroscience
• Memory Research

Background:

• Hippocampal neuronal sequences are implicated in episodic memory formation and retrieval.
• Understanding the mechanisms governing these sequences is crucial for memory research.

Purpose of the Study:

• To investigate the theoretical underpinnings of neuronal spike sequences in the hippocampus.
• To explore how network capacity and inhibitory feedback influence memory replay.
• To link theoretical models to experimental observations like sharp-wave ripples.

Main Methods:

• Development of a mean-field theory for neuronal spike sequences.
• Analysis of sequence stability in phase space under varying network loads.
• Modeling the effects of inhibitory feedback on sequence replay and network capacity.

Main Results:

• Neuronal sequences become unstable at maximum network memory capacity.
• Inhibitory feedback rescues sequence replay, inducing oscillations and increasing capacity.
• Transient sequences in overloaded networks with feedback inhibition may model sharp-wave ripple activity.

Conclusions:

• Inhibitory feedback plays a critical role in stabilizing neuronal sequences for memory.
• The proposed theory offers a mechanistic explanation for memory-related activity during hippocampal sharp-wave ripples.
• This work bridges theoretical modeling and experimental findings in memory neuroscience.