Neural correlates of 3D versus 2D perception: An activation likelihood estimation meta-analysis

Area of Science:

• Neuroscience
• Cognitive Science
• Visual Perception

Background:

• Hundreds of neuroimaging studies have investigated 3D shape perception, but a lack of consensus exists due to varied stimuli and depth cues.
• Existing research lacks a unified understanding of the neural basis for distinguishing 3D from 2D shapes across different visual inputs.

Purpose of the Study:

• To synthesize existing neuroimaging data on 3D shape perception using a coordinate-based meta-analysis.
• To investigate the neural correlates of 3D versus 2D shape perception across diverse depth cues.
• To identify common and cue-specific brain regions involved in processing three-dimensional visual information.

Main Methods:

• A systematic literature review identified 25 empirical studies using Medline, PsychInfo, and Embase databases.
• Activation Likelihood Estimation (ALE) meta-analysis was employed to pool coordinate data from selected studies.
• Analyses included a full-sample assessment, cue-specific sub-analyses (disparity, motion, shading, texture), and contrast analyses.

Main Results:

• Full-sample analysis indicated widespread activation in the high-level visual cortex for 3D shape perception, irrespective of the depth cue.
• Disparity-defined 3D shapes engaged dorsal stream areas (e.g., intraparietal sulcus), while motion-defined shapes recruited ventral stream regions.
• Monocularly-defined 3D shapes activated both ventral (inferior lateral cortex) and dorsal (IPS) areas, with left lateral occipital cortex involvement when contrasted with disparity cues.

Conclusions:

• 3D shape representations are distributed across both ventral and dorsal visual pathways, independent of the specific depth cues used.
• Evidence suggests laterality in the neural representation of 3D versus 2D shapes.
• The findings provide a more comprehensive understanding of the neural architecture supporting three-dimensional visual perception.