Complementary tasks to measure working memory in distinct prefrontal cortex subregions in rats

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Behavioral Neuroscience

Background:

• The prefrontal cortex (PFC) plays a critical role in executive functions, including working memory.
• Different subregions within the PFC may be specialized for processing distinct types of information.
• Understanding the functional dissociation of PFC subregions is crucial for comprehending working memory mechanisms.

Purpose of the Study:

• To investigate the role of the agranular insular cortex and prelimbic cortex in working memory.
• To determine if these PFC subregions exhibit stimulus modality-specific functions.
• To examine the neural basis of odor-guided versus visually-guided delayed win-shift behavior.

Main Methods:

• Lidocaine-induced inactivation was used to temporarily inactivate specific PFC subregions in rats.
• Rats were trained on odor-guided and visually-guided delayed win-shift tasks using a radial-arm maze.
• Control experiments were conducted to ensure neuroanatomical and behavioral specificity.

Main Results:

• Inactivation of the agranular insular cortex impaired acquisition of the odor-guided delayed win-shift task.
• Inactivation of the prelimbic cortex impaired acquisition of the visually-guided delayed win-shift task.
• This dissociation indicates stimulus-modality-specific roles for these PFC subregions.

Conclusions:

• The agranular insular cortex and prelimbic cortex have distinct, modality-specific roles in working memory.
• Stimulus modality is a critical factor in revealing the functional specialization of PFC subregions.
• These findings contribute to a better understanding of the neural architecture supporting working memory in the PFC.