Cue Competition Affects Temporal Dynamics of Edge-assignment in Human Visual Cortex

摘要

Edge-assignment determines the perception of relative depthnacross an edge and the shape of the closer side. Many cues determinenedge-assignment, but relatively little is known about thenneural mechanisms involved in combining these cues. Here, wenmanipulated extremal edge and attention cues to bias edgeassignmentnsuch that these two cues either cooperated or competed.nTo index their neural representations, we flickered figurenand ground regions at different frequencies and measured thencorresponding steady-state visual-evoked potentials (SSVEPs).nFigural regions had stronger SSVEP responses than ground regions,nindependent ofwhether they were attended or unattended.nIn addition, competition and cooperation between the two edgeassignmentncues significantly affected the temporal dynamics ofnedge-assignment processes. The figural SSVEP response peakednearlier when the cues causing it cooperated than when they competed,nbut sustained edge-assignment effects were equivalent forncooperating and competing cues, consistent with a winner-takeallnoutcome. These results provide physiological evidence thatnfigure–ground organization involves competitive processes thatncan affect the latency of figural assignment. ■