Qihan Wu¹, Grant T. Fairchild^2,3, Lars Strother², Kallie E. McDonald², Erez Freud⁴, Jacqueline C. Walsh-Snow^1,2; ¹Department of Psychology, University of Utah, ²Department of Psychology, University of Nevada, Reno, ³Department of Psychology, Emory University, ⁴Department of Psychology and the Centre for Vision Research, York University

Although the neural basis of object perception has been studied extensively, most research has relied on artificial stimuli in the form of pictures or computer images, rather than tangible, real-world objects. This approach overlooks the possibility that the brain’s processes and organization reflect the important features of naturalistic objects and environments, including tangibility and actability. Here, we used fMRI to compare shape selectivity for tangible objects versus matched planar photographs of objects across the ventral and dorsal visual pathways. We were particularly interested in whether shape-processing areas of dorsal cortex would show enhanced responses to tangible objects compared to pictures, given the pathway’s role in spatial processing and action guidance. We used a parametric shape scrambling paradigm in which human participants directly viewed 3D-printed everyday objects and matched photos of those objects, each presented with different levels of scrambling. The results revealed distinct format-dependent patterns of shape selectivity: dorsal regions showed stronger shape selectivity for tangible objects than for pictures, whereas ventral regions responded similarly across formats. Our results suggest that dorsal object areas are preferentially tuned to the properties of real-world, manipulable objects, while ventral areas encode object shape independently of physical format. This work provides new insights into the functional role of dorsal shape areas and highlights the value of using real objects to study the integrated functioning of perceptual and motor systems.

Acknowledgements: National Eye Institute of the National Institutes of Health (R01EY026701)