Functional connectivity with the anterior and posterior hippocampus during spatial memory

Area of Science:

• Neuroscience
• Cognitive Psychology
• Neuroimaging

Background:

• The hippocampus exhibits functional specialization along its long-axis, with anterior regions linked to memory encoding and posterior regions to retrieval.
• The HERNET model proposes distinct network engagements for encoding (anterior hippocampus, attention network) and retrieval (posterior hippocampus, default network).

Purpose of the Study:

• To investigate the differential connectivity of the anterior and posterior hippocampus with attention and default networks during spatial memory encoding and retrieval.
• To test the predictions of the HERNET model using functional magnetic resonance imaging (fMRI).

Main Methods:

• Participants underwent fMRI while performing a spatial memory encoding and retrieval task.
• Generalized psychophysiological interaction (PPI) analyses were used to examine connectivity between hippocampal subregions and the rest of the brain.

Main Results:

• The anterior hippocampus showed preferential connectivity with the attention network during memory encoding.
• The posterior hippocampus demonstrated preferential connectivity with the default network during memory retrieval.
• Location-specific connectivity patterns were observed for right visual field items during both encoding and retrieval.

Conclusions:

• The findings support the HERNET model by demonstrating distinct network interactions for hippocampal subregions during memory encoding and retrieval.
• The anterior hippocampus engages with the attention network for encoding, and the posterior hippocampus engages with the default network for retrieval.
• These results highlight the specialized roles of hippocampal subregions and their network interactions in memory processes.