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. 2019 Oct 9;8:e48182. doi: 10.7554/eLife.48182

Figure 1. Experimental design and rationale of schema-based information sorting.

(a) The stimulus set consisted of six natural scenes (three indoor, three outdoor). Each scene was split into six rectangular fragments. (b) During the fMRI and EEG recordings, participants performed an indoor/outdoor categorization task on individual fragments. Notably, all fragments were presented at central fixation, removing explicit location information. (c) We hypothesized that the visual system sorts sensory input by spatial schemata, resulting in a cortical organization that is explained by the fragments’ within-scene location, predominantly in the vertical dimension: Fragments stemming from the same part of the scene should be represented similarly. Here we illustrate the hypothesized sorting in a two-dimensional space. A similar organization was observed in multi-dimensional scaling solutions for the fragments’ neural similarities (see Figure 1—figure supplement 1 and Video 1). In subsequent analyses, the spatiotemporal emergence of the schema-based cortical organization was precisely quantified using representational similarity analysis (Figure 2).

Figure 1.

Figure 1—figure supplement 1. MDS visualization of neural RDMs 34 MDS visualization of neural RDMs.

Figure 1—figure supplement 1.

(a/b) A multi-dimensional scaling (MDS) of the fragments’ neural similarity in OPA (a) and after 200 ms of processing (b) revealed a sorting according to vertical location, which was visible in a two-dimensional solution. This visualization suggests that schemata are a prominent organizing principle for representations in OPA and after 200 ms of vision. A time-resolved MDS for the EEG data can be found in Video 1.