Dynamic layer-specific processing in the prefrontal cortex during working memory.

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Neuroimaging

Background:

• The dorsolateral prefrontal cortex (dlPFC) is crucial for working memory (WM).
• The functional roles of specific cytoarchitectonic layers within the dlPFC during WM remain poorly understood.
• Understanding laminar circuitry is key to deciphering dlPFC's contribution to cognition.

Purpose of the Study:

• To investigate layer-specific activity in the human dlPFC during working memory tasks.
• To examine how WM load and motor responses modulate activity across different dlPFC cortical layers.
• To elucidate the functional laminar organization of the dlPFC in WM.

Main Methods:

• Functional magnetic resonance imaging (fMRI) at ultra-high resolution was employed.
• Participants performed a delayed-match-to-sample task to assess WM.
• Layer-specific BOLD responses were analyzed in relation to WM load and motor demands.

Main Results:

• Superficial dlPFC layers showed preferential activation in response to WM load during delay and retrieval.
• Multivariate patterns encoding WM load in superficial layers exhibited dynamic changes across task phases.
• Both superficial and deep dlPFC layers were similarly involved in motor response execution.

Conclusions:

• Results reveal a lamina-specific functional organization within the dlPFC for working memory processing.
• Superficial layers play a distinct role in WM load encoding, with dynamic representations.
• The findings challenge previous notions of preferential deep layer involvement in motor responses within the dlPFC.