Efficient coding in working memory is adapted to the structure of the environment

Area of Science:

• Cognitive Neuroscience
• Neuroscience
• Psychology

Background:

• Working memory (WM) capacity is limited, necessitating efficient coding strategies.
• The brain's adaptive organization of WM representations based on environmental structure is not well understood.

Purpose of the Study:

• To investigate how the brain adaptively organizes working memory representations to maximize coding efficiency.
• To examine the impact of environmental structure on WM performance and neural mechanisms.

Main Methods:

• Participants performed a sequence recall task with manipulated directional consistency in a 2D feature space.
• Magnetoencephalography (MEG) was used to analyze neural activity during WM maintenance.
• Behavioral performance and neural reactivation patterns were correlated.

Main Results:

• WM performance was enhanced in structured (consistent direction) compared to non-structured (inconsistent direction) contexts, especially for individuals with lower WM capacity.
• Consistent sequences engaged anterior temporal and medial frontal cortices for abstract representations.
• Inconsistent sequences led to preferential reactivation of item-specific representations in parietal regions.

Conclusions:

• The brain adaptively switches between relational and item-based coding strategies to mitigate WM constraints, demonstrating a neural efficiency principle.
• Environmental structure significantly shapes WM organization, impacting cognitive flexibility and neural resource allocation.