Neural correlates of structural and holistic object representations in dependence of attention

M Guggenmos1, R Cichy2, A Richardson-Klavehn3, J-D Haynes1, P Sterzer4, V Thoma5

1Bernstein-Center, Berlin, Germany
2CSAIL, MIT, MA, United States
3Department of Neurology, Otto-von-Guericke Universität, Magdeburg, Germany
4Visual Perception Laboratory, Charité - Universitätsmedizin Berlin, Germany
5School of Psychology, University of East London, United Kingdom
Contact: matthias.guggenmos@bccn-berlin.de

A fundamental question in visual cognition is whether objects are stored as structural (part-based) descriptions or as holistic views. Hybrid models integrate both formats of representation and predict a critical role for attention. Visual attention enables structural descriptions by segmenting and binding object components. However, also in the absence of attention recognition may still proceed by matching objects to view-based representations. In this fMRI study we probed object-responsive brain areas for characteristics that are compatible with either holistic or structural object representations. We devised a novel paradigm in which participants viewed images of intact and slightly scrambled (split) objects under conditions of spatial attention or inattention. Univariate fMRI analysis showed increased engagement of lateral occipital cortex for attended (but not unattended) split objects relative to intact objects – compatible with a structural description account. Irrespective of attention we found elevated activation for intact relative to split objects – compatible with holistic representations – in the hippocampus and the superior frontal gyrus. FMRI decoding analysis further corroborated the presence of both structural and holistic representations as predicted by a hybrid model of object recognition. Our results reveal the representational format of object representation in the human brain and elucidate the dependence on attentional demands.

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