Macaque prefrontal cortex integrates multiple components for metacognitive judgments of working memory.

Area of Science:

• Neuroscience
• Cognitive Science
• Computational Neuroscience

Background:

• Metamemory, the ability to assess one's own memory, is crucial for cognitive control.
• The neural basis of metamemory, particularly in working memory, is not fully understood.
• It remains unclear if metamemory relies solely on memory strength or requires distinct computations.

Purpose of the Study:

• To investigate the metacognitive mechanisms underlying working memory (WM) in non-human primates.
• To explore how the prefrontal cortex (PFC) represents memory confidence and guides behavior.
• To identify neural codes for meta-working memory (meta-WM) signals.

Main Methods:

• Used two-photon calcium imaging to record neural activity in the macaque PFC.
• Monkeys performed a spatial sequence memorization task with varying difficulty.
• Monkeys could opt out of retrieval for a smaller reward, indicating their confidence (meta-WM).

Main Results:

• PFC neurons jointly encoded remembered locations and their uncertainties, reflecting WM strength.
• Baseline neural activity, influenced by trial history and arousal, predicted opt-out decisions.
• A distinct neural code for meta-WM was identified, integrating WM strength with contextual cues.

Conclusions:

• The PFC implements metacognitive computations by integrating memory strength with contextual cues.
• Neural geometry in the PFC generates a meta-WM signal that guides behavioral choices.
• This study provides insights into the neural mechanisms of self-monitoring in working memory.