Interplay between persistent activity and activity-silent dynamics in the prefrontal cortex underlies serial biases...

Area of Science:

• Neuroscience
• Cognitive Science
• Computational Neuroscience

Background:

• Working memory is traditionally linked to persistent neuronal spiking.
• Recent theories propose 'activity-silent' mechanisms as alternative substrates.
• The interplay between these mechanisms remains incompletely understood.

Purpose of the Study:

• To investigate the interaction between activity-based and activity-silent mechanisms in prefrontal cortex during working memory.
• To determine how these interactions influence memory reactivations and behavioral biases.
• To establish the causal role of prefrontal cortex activity in working memory.

Main Methods:

• Analysis of monkey and human electrophysiology data.
• Decoding stimulus information from neural activity and synchrony.
• Computational modeling of integrated memory mechanisms.
• Application of transcranial magnetic stimulation to the human prefrontal cortex.

Main Results:

• Attractor dynamics interact with activity-silent mechanisms in the prefrontal cortex.
• Memory reactivations, linked to activity-silent traces, enhance serial biases in spatial working memory.
• Stimulus information was present in latent, activity-silent traces between trials.
• Prefrontal cortex stimulation causally enhanced these serial biases.

Conclusions:

• Working memory utilizes a hybrid system integrating active spiking and activity-silent traces.
• Prefrontal cortex plays a crucial role in memory reactivation and its behavioral consequences.
• Activity-silent mechanisms are essential for maintaining and recalling information in working memory.