Hierarchical Replay of Multi-regional Sequential Spiking Associated with Working Memory

Area of Science:

• Neuroscience
• Computational Neuroscience

Background:

• Understanding the neural basis of working memory is crucial.
• The precise temporal dynamics of neural activity remain largely unknown.

Purpose of the Study:

• To investigate how millisecond-scale neural activity underlies second-scale behaviors.
• To decipher the cross-region organization of neural activity during an olfactory working-memory task.

Main Methods:

• Whole-brain neural activity recording in mice.
• Spike-correlograms analysis to identify spike couplings.
• Analysis of neural motifs, including chains and loops.

Main Results:

• Millisecond spike couplings were enriched among memory-encoding neurons with similar odor preferences.
• Spike coupling formed motifs (chains, loops) primarily in hippocampal and prefrontal cortex.
• Activity motifs were replayed before, after, and during task performance.
• Motifs showed hierarchical organization with increasing time constants and neuron participation.

Conclusions:

• Hierarchically organized and replayed cross-region spiking motifs are modulated during working memory.
• These motifs provide a potential mechanism for perceptual working-memory maintenance.