Brain and Mind Institute, University of Western Ontario, London, Canada; Robarts Research Institute Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
Department of Psychology, Florida State University, Tallahassee, United States
Daria Proklova
Brain and Mind Institute, University of Western Ontario, London, Canada
Alexander N Minos
Brain and Mind Institute, University of Western Ontario, London, Canada
Lisa M Saksida
Brain and Mind Institute, University of Western Ontario, London, Canada; Robarts Research Institute Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada; Department of Physiology and Pharmacology, University of Western Ontario, London, Canada
Timothy J Bussey
Brain and Mind Institute, University of Western Ontario, London, Canada; Robarts Research Institute Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada; Department of Physiology and Pharmacology, University of Western Ontario, London, Canada
Brain and Mind Institute, University of Western Ontario, London, Canada; Robarts Research Institute Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada; School of Biomedical Engineering, University of Western Ontario, London, Canada; Department of Medical Biophysics, University of Western Ontario, London, Canada
Vision neuroscience has made great strides in understanding the hierarchical organization of object representations along the ventral visual stream (VVS). How VVS representations capture fine-grained visual similarities between objects that observers subjectively perceive has received limited examination so far. In the current study, we addressed this question by focussing on perceived visual similarities among subordinate exemplars of real-world categories. We hypothesized that these perceived similarities are reflected with highest fidelity in neural activity patterns downstream from inferotemporal regions, namely in perirhinal (PrC) and anterolateral entorhinal cortex (alErC) in the medial temporal lobe. To address this issue with functional magnetic resonance imaging (fMRI), we administered a modified 1-back task that required discrimination between category exemplars as well as categorization. Further, we obtained observer-specific ratings of perceived visual similarities, which predicted behavioural discrimination performance during scanning. As anticipated, we found that activity patterns in PrC and alErC predicted the structure of perceived visual similarity relationships among category exemplars, including its observer-specific component, with higher precision than any other VVS region. Our findings provide new evidence that subjective aspects of object perception that rely on fine-grained visual differentiation are reflected with highest fidelity in the medial temporal lobe.
