Different Subregions of Monkey Lateral Prefrontal Cortex Respond to Abstract Sequences and Their Components.

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Primate Brain Research

Background:

• Sequential information processing is vital for daily activities.
• The posterior fundus of area 46 (LPFC) previously showed responses to abstract sequence rule changes.
• It remained unclear if this region also processes sequence components like periodicity and identity, or if it dissociates from ventral LPFC.

Purpose of the Study:

• To investigate whether the posterior fundus of area 46 responds to image periodicity and identity in isolation.
• To determine if this region dissociates from more ventral LPFC subregions regarding sequence processing.
• To elucidate functional specialization within LPFC for processing different types of stimulus regularities.

Main Methods:

• Awake functional magnetic resonance imaging (fMRI) was employed in three male macaque monkeys.
• Two no-report visual tasks were designed: one with abstract visual sequences, and another with matched image periodicity and identities but no sequences.
• Neural responses were analyzed to identify differential activation patterns.

Main Results:

• The posterior fundus of area 46 selectively responded to violations of abstract sequence rules.
• In contrast, the ventral bank of area 46 responded to changes in image periodicity and identity, but not abstract sequence rules.
• These findings reveal distinct functional roles for subregions within LPFC.

Conclusions:

• A functional specialization exists within anatomical substructures of the lateral prefrontal cortex (LPFC).
• This specialization allows for signaling different kinds of stimulus regularities, contributing to pattern identification and world modeling.
• This dissociation supports the complex cognitive functions of the LPFC in navigating everyday sequential information.