A new ERP repetition paradigm to assess independence of regularity representations in the extrastriate cortex.

Abstract

An ERP component called the Sustained Posterior Negativity (SPN) indexes the brain response to regularity in visual patterns (e.g. vertical reflectional symmetry, horizontal reflectional symmetry or rotational symmetry). However it is unclear if different regularities are coded by independent or overlapping neural populations. Previous work has successfully exploited repetition effects to assess representational independence, and we adapted this approach to investigate visual regularity. Experiment 1 (N = 48) found that SPN amplitude increased when three reflectional symmetry patterns were presented sequentially. This SPN priming effect did not survive changes in retinal location (Experiment 2, N = 48) or non-orthogonal changes in axis orientation (Experiment 3, N= 48). However, SPN priming transferred between vertical and horizontal axis orientation (Experiment 4, N= 48) and between reflectional and rotational symmetry (Experiment 5, N= 48). We conclude that visual regularities at different retinal locations are coded independently. However, there is some overlap between different regularities presented at the same retinal location.

Electrophysiological priming effects confirm that the extrastriate symmetry network is not gated by luminance polarity

“…Selective SPN priming effect when novel exemplars are shown. Data from Makin, Tyson-Carr, et al (2020). Participants viewed a sequence of three reflectional symmetries (left).…”

“…Furthermore, observed power for the significant parametric main effect of Sequence position was just 0.638, while the observed power of the linear contrast was just 0.545. However, SPN priming was replicated by Makin, Tyson-Carr, et al (2020) in all the expected conditions (plus some unexpected conditions) across five experiments with 48 participants in each. Here effect size ranged from 0.110 to 0.290.…”

“…Experiment 1 of Makin, Tyson-Carr, et al (2020) found SPN priming with repeated presentation of different exemplars, but not repeated presentation of identical exemplars (Figure 1). Other experiments in Makin, Tyson-Carr, et al (2020) demonstrated that SPN priming survives changes in regularity type, but not changes in retinal location, or unpredictable changes in axis orientation. In the current work, we tested whether SPN priming would survive changes in element luminance polarity, as predicted by the non-selectivity account.…”

“…Kim, Biederman, Lescroart, & Hayworth, 2009;Kourtzi & Kanwisher, 2001), our recent work has exploited SPN priming to assess the independence of different symmetry representations (Makin, Tyson-Carr, Rampone, Derpsch, & Bertamini, 2020). Experiment 1 of Makin, Tyson-Carr, et al (2020) found SPN priming with repeated presentation of different exemplars, but not repeated presentation of identical exemplars (Figure 1). Other experiments in Makin, Tyson-Carr, et al (2020) demonstrated that SPN priming survives changes in regularity type, but not changes in retinal location, or unpredictable changes in axis orientation.…”

“…We used different exemplars ( Figure 2), known to produce SPN priming (red wave in Figure 1). Following Makin, Tyson-Carr, et al (2020), we used a secondary task that was unrelated to symmetry: Our participants discriminated between normal sequences with three patterns, and oddball sequences, with a blank in the middle (Figure 2b).…”