Cognitive maps for hierarchical spaces in the human brain.

Area of Science:

• Cognitive Neuroscience
• Spatial Cognition
• Neuroimaging

Background:

• Everyday environments are often hierarchically organized, with nested spaces.
• Understanding how the brain represents these complex spatial structures is crucial.

Purpose of the Study:

• To investigate the neural mechanisms underlying the representation of hierarchically organized environments.
• To examine how the brain integrates information across nested spatial subspaces.

Main Methods:

• Familiarization with a virtual environment (building within a courtyard).
• Functional magnetic resonance imaging (fMRI) during a spatial memory task.
• Behavioral analysis of response accuracy and reaction times.
• Multivoxel pattern analysis (MVPA) of fMRI data.

Main Results:

• Behavioral performance was impaired (lower accuracy, longer response times) when integrating information across subspaces.
• fMRI revealed differential activation in scene-responsive and medial temporal lobe regions during integration.
• Brain activity in the retrosplenial complex, occipital place area, and hippocampus correlated with behavioral integration effects.
• MVPA indicated that neural patterns reflected the hierarchical organization of the environment.

Conclusions:

• The brain forms cognitive maps of nested spaces by segmenting them into subspaces.
• An active cognitive process is employed to integrate these subspaces for spatial memory.
• These neural mechanisms may support hierarchical coding in memory more broadly.