Bringing the real world into the fMRI scanner: Robust release from adaptation for 2D pictures but not actual 3D objects

Abstract

Our understanding of the neural underpinnings of perception is largely built upon studies that have employed 2-dimensional (2D) planar images. When viewing a sequence of two 2D pictures of objects, a change in objects produces a characteristic release from adaptation within ventral visual object-selective areas. Here we use functional brain imaging in humans to examine whether neural populations show a similar effect for real-world 3-dimensional (3D) objects. We found robust release from adaptation for 2D images of objects within classic object-selective cortical regions along the ventral and dorsal visual processing streams. Surprisingly however, BOLD responses remained in the adapted state on trials involving different 3D stimuli suggesting broader neural tuning for real-world objects. Our findings indicate that the neural mechanisms involved in processing real-world 3D objects are distinct from those that arise when we encounter a 2D representation of the same items. Incorporating real-world stimuli into fMRI designs may provide a more thorough understanding of the neural mechanisms of human vision.

Natural Sciences and Engineering Research Council of Canada, Canadian Institutes of Health Research to the Group on Action and Perception.