The impact of attending to distractors: A study of low-level visual working memory.
Berry, A., Rutman, A., Clapp, W., Zanto, T., Gazzaley, A. Cognitive Neuroscience Meeting (2008)

Top-down modulation is characterized by differential enhancement or suppression of neural activity in sensory cortical regions. One’s ability to attend to pertinent sensory information and ignore irrelevant stimuli is often correlated with this neural modulation. In a previous study, electroencephalography (EEG) was recorded as subjects participated in a single face delayed-recognition task in which face distractors were introduced during the delay period.  The degree to which the distractors were attended impacted their performance as reflected in the modulation of the P100 and N170 components for the distractors.  The present study used the same paradigm, but utilized coherent motion stimuli to test whether early neural modulation exists for lower-level visual stimuli, and what impact distraction has on performance.  In a delayed-recognition paradigm, subjects were asked to maintain their memory for motion direction over a delay period in which there either was an attended visual distractor (swirling dots), an unattended visual distractor, or no distractor.  A passive viewing condition served as a baseline to measure relative enhancement and suppression.  Working memory accuracy when the distractor was attended to correlated with measures of enhancement in N170 latency and amplitude for the distractor. Also, the impact of distraction on response time correlated with enhancement in N170 latency to distracting stimuli, such that subjects who showed the greatest enhancement for the attended distractors demonstrated the poorest working memory performance.  This study suggests top-down modulation of early visual processing correlates with the impact distraction has on working memory performance for lower-level visual stimuli.