The neural mechanisms of percept-memory comparison in visual working memory

► The anterior N2, with its neural-source at anterior cingulate cortex (ACC), reflects the mismatch comparing process during a distinct comparison from attention shift between the incoming perceptual input and visual working memory. ► The mismatch information during visual percept-memory comparison activated the frontal theta (5-8 Hz) regardless of task relevancy. ► A distinct comparison stage after attention-shift stage initiated at around 230 ms.