Effects of prior knowledge on brain activation and functional connectivity during memory retrieval

Area of Science:

• Neuroscience
• Cognitive Psychology
• Memory Research

Background:

• The ventral medial prefrontal cortex (vmPFC) is implicated in schema-related memory.
• The role of hippocampal subregions in retrieving schema-related memories is debated.
• How prior knowledge (PK) modulates functional connectivity (FC) in memory retrieval is unclear.

Purpose of the Study:

• To investigate the involvement of hippocampal subregions in schema-related memory retrieval.
• To examine how prior knowledge (PK) affects functional connectivity (FC) between the vmPFC, hippocampus, and other brain regions during memory retrieval over time.

Main Methods:

• Participants learned information from familiar (high PK) and unfamiliar (low PK) categories.
• A recognition task was performed in an fMRI scanner at 20 minutes, 1 day, and 1 week post-learning.
• Brain activation and functional connectivity (FC) were analyzed based on prior knowledge (PK) and memory performance.

Main Results:

• Anterior-medial hippocampus (amHPC) activation was higher for correctly retrieved high PK items.
• Posterior hippocampus (pHPC) and vmPFC activation were higher for correctly rejected new high PK items.
• Functional connectivity (FC) between vmPFC and specific hippocampal/cortical regions varied with PK levels during correct rejections.

Conclusions:

• Distinct brain networks involving the vmPFC, hippocampal subregions, and cognitive control regions are recruited for retrieving information with varying levels of prior knowledge (PK).
• Prior knowledge dynamically shapes neural activity and connectivity patterns during memory retrieval.