Evidencing a place for the hippocampus within the core scene processing network

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Neuroimaging

Background:

• Established "core" brain regions for scene stimuli include posterior parahippocampal gyrus (PHG), retrosplenial cortex (RSC), and transverse occipital sulcus (TOS).
• The hippocampus (HC) is implicated in scene processing, but its scene-sensitivity relative to other core regions remains under-investigated.
• Understanding individual variability in scene-sensitive regions is crucial for accurate neuroimaging interpretation.

Purpose of the Study:

• To characterize the frequency and consistency of individual scene-preferential responses in the PHG, RSC, TOS, and HC.
• To compare scene-sensitivity within the HC to established core scene-processing regions.
• To investigate inter-individual variability in scene-sensitive cortex localization.

Main Methods:

• Analysis of a large dataset (n=51) using functional neuroimaging during a one-back working memory task for scenes, objects, and scrambled objects.
• Application of independently-defined anatomical regions of interest (ROIs) to individual-level functional data.
• Examination across different voxel-wise thresholds and spatial filters for an unbiased approach.

Main Results:

• A majority of participants showed preferential scene clusters in PHG (up to 100%), TOS (up to 94%), and RSC (up to 76%).
• A comparable proportion of individuals (up to 88%) exhibited significant scene-related clusters within their HC ROIs.
• Probabilistic overlap maps showed peaks near group-level findings, but inter-individual consistency varied across regions and thresholds.

Conclusions:

• The hippocampus (HC) demonstrates significant scene-preferential activation, comparable to established core regions.
• Substantial inter-individual variability exists in the localization and consistency of scene-sensitive cortex.
• These findings have implications for localizing and interrogating scene-sensitive cortex, especially within medial temporal lobe regions like the HC.