p325fig08.44 Attentional feedback from MST-to-MT-to-V2 can strengthen one branch of a chopstick (left image).  Then bipole cell activations that are strengthened by this feedback can complete that chopstick's boundaries across the ambiguous X region (right image).<BR>||  The role of MT-V1 feedback.  Motion-form feedback: MT-to-V2 feedback strengthens boundaries of one bar.  Bipole boundary completion: Bipole grouping helps to complete bar boundary even if motion grouping does not cross the gap.