Novelty modulates human striatal activation and prefrontal-striatal effective connectivity during working memory...

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Neuroimaging

Background:

• The basal ganglia (BG) are crucial for motor control and increasingly recognized for cognitive functions, including working memory.
• Working memory relies on gating relevant information and filtering irrelevant stimuli, a process potentially analogous to motor response gating by the BG.
• The role of stimulus novelty in working memory and its impact on corticostriatal function remains understudied.

Purpose of the Study:

• To investigate the influence of working memory item novelty on corticostriatal function and connectivity.
• To explore the neural mechanisms underlying the gating of novel information during working memory encoding.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was employed in 74 healthy volunteers.
• Participants performed a Sternberg working memory task with novel and trained stimuli across encoding and retrieval phases.
• Dynamic causal modeling (DCM) analyzed functional connectivity within corticostriatal circuits.

Main Results:

• Significant activation was observed in the anterior striatum during the encoding of novel working memory items.
• Dynamic causal modeling revealed that novelty encoding positively modulated the connection from the dorsolateral prefrontal cortex (DLPFC) to the anterior striatum.
• These findings highlight the anterior striatum's role in processing novelty within working memory.

Conclusions:

• The basal ganglia play a significant role in cognitive functions, specifically in gating novel information for working memory.
• The dorsolateral prefrontal cortex (DLPFC) acts as a top-down regulator, influencing striatal function to facilitate the input gating of novel working memory materials.
• This research provides a mechanistic understanding of how novelty is processed and integrated into working memory via corticostriatal pathways.