Redundant prefrontal hemispheres adapt storage strategy to working memory demands

Area of Science:

• Neuroscience
• Cognitive Science
• Computational Neuroscience

Background:

• The prefrontal cortex (PFC) hemispheres must coordinate to maintain a unified visual spatial representation.
• Two theories exist: specialized architecture (contralateral control) vs. redundant architecture (joint control).

Purpose of the Study:

• To investigate the interhemispheric organization of the prefrontal cortex during visuo-spatial working memory.
• To determine whether the brain uses specialized or redundant strategies for visual spatial processing.

Main Methods:

• Simultaneous bilateral prefrontal cortex recordings in macaque monkeys during a visuo-spatial working memory task.
• Analysis of behavioral imprecision, decoding errors, and serial dependence.
• Attractor network simulations to model interhemispheric interactions.
• Validation of computational models with human and monkey data.

Main Results:

• Both hemispheres equally predicted behavioral imprecision.
• Decoding errors showed weak interhemispheric correlation.
• Serial dependence was localized within hemispheres, suggesting redundancy.
• Simulations indicated redundancy enhances precision under low demand; weak coupling increases capacity under high demand by enabling specialization.

Conclusions:

• The prefrontal cortex exhibits a versatile, weakly coupled, redundant organization.
• This architecture dynamically adapts to varying cognitive demands, balancing precision and capacity.
• Findings reconcile opposing theories on interhemispheric coordination in visuo-spatial working memory.