Temporal-Order-Based Attentional Priority Modulates Mnemonic Representations in Parietal and Frontal Cortices

Area of Science:

• Neuroscience
• Cognitive Psychology
• Neuroimaging

Background:

• The roles of occipital, parietal, and frontal cortices in visual working memory are debated.
• Previous findings on mnemonic information in parietal and frontal regions are inconsistent.

Purpose of the Study:

• To investigate if mnemonic representations in frontoparietal regions are modulated by attentional priority based on temporal order.
• To determine if the most recent item, with higher temporal priority, is preferentially encoded.

Main Methods:

• Functional magnetic resonance imaging (fMRI) and an inverted encoding model were used.
• Population-level orientation representations were reconstructed in occipital, parietal (IPS), and frontal (FEF) areas.
• A change detection task on color rings was employed to rule out alternative explanations.

Main Results:

• Occipital cortex showed orientation representations regardless of serial order.
• Parietal and frontal cortices exhibited stronger orientation representations for the second (more recent) grating.
• Control experiments excluded residual stimulus-driven or motor preparatory signals.

Conclusions:

• Mnemonic representations in parietal and frontal cortices are modulated by attentional priority signals.
• Temporal order significantly influences the encoding of visual information in higher-level brain regions.