Dynamic changes in orbitofrontal-hippocampal connectivity linked to cognitive map formation in humans

Area of Science:

• Neuroscience
• Cognitive Science
• Spatial Cognition

Background:

• The hippocampus (HIP), parahippocampal cortex (PHC), orbitofrontal cortex (OFC), and retrosplenial cortex (RSC) are implicated in spatial navigation.
• The precise interaction mechanisms for forming and using cognitive maps across these brain regions are not fully understood.

Purpose of the Study:

• To investigate how navigational complexity influences brain activation and behavior during abstract spatial navigation.
• To explore the functional connectivity and effective connectivity between key brain regions involved in cognitive map formation.

Main Methods:

• Task-based functional magnetic resonance imaging (fMRI) was used during a navigation task in abstract spaces.
• Navigational complexity was manipulated by varying navigation stages, spatial dimensions, and target distance.
• Generalized psychophysiological interaction (gPPI) and dynamic causal modeling (DCM) were employed to analyze brain region connectivity.

Main Results:

• Lateral OFC (lOFC) and medial OFC (mOFC) showed differential responses to navigation stages.
• Medial temporal lobe (MTL) regions (HIP, PHC, RSC) were involved in processing target distance.
• gPPI revealed increased lOFC-MTL connectivity and decreased mOFC-MTL connectivity during navigation.
• DCM identified self-connectivity of mOFC and HIP, and PHC-to-HIP connectivity as predictive of behavioral differences and navigation strategies.

Conclusions:

• The OFC exhibits functional divisions, with lateral and medial parts playing distinct roles in navigation.
• Neural dynamics, including regional activation and inter-regional connectivity, underpin abstract spatial cognition.
• Understanding these neural mechanisms provides insights into adaptive behavior in complex environments.