Neural correlates of boundary extension during visual imagination

Area of Science:

• Cognitive Neuroscience
• Neuroimaging

Background:

• Boundary extension (BE) describes the common phenomenon of recalling a scene with a wider visual field than actually perceived.
• Understanding the neural mechanisms underlying BE is crucial for comprehending visual memory and potential false memory formation.

Purpose of the Study:

• To investigate the neural correlates of boundary extension (BE) using multivoxel pattern analysis (MVPA).
• To differentiate between neural representations of perceived scenes and imagined scenes in relation to BE.
• To explore the role of early versus high-level visual cortex in BE during visual imagery.

Main Methods:

• Employed whole-brain searchlight MVPA to train classifiers distinguishing between close-up and wide-angle scene views.
• Subjects studied scenes and later imagined them from memory, allowing for the analysis of neural patterns during visual imagery.
• Compared classification accuracy for perceived versus imagined scenes to identify brain regions supporting BE.

Main Results:

• Found BE-consistent neural patterns in high-level visual areas, such as the posterior superior parietal cortex, during visual imagery.
• Observed a reversal of this pattern in early visual cortex, indicating better classification of close-up views, suggesting distinct neural representations.
• Demonstrated that the neural signature of BE during imagery differs from perception and varies across visual processing stages.

Conclusions:

• The findings suggest active maintenance of boundary-extended scene representations in memory within high-level visual regions.
• The observed distinction between early and late visual cortex patterns offers new insights into visual imagery and memory.
• The developed MVPA method shows potential as a tool for decoding false memories in the brain.