Abstract
Recent work has demonstrated that a specific event-related potential (ERP) component, the distractor positivity (Pd), indexes distractor suppression during visual search. Here, we provide the first evidence for a homologous component in nonhuman primates. Monkeys performed an adapted version of the additional singleton paradigm in which they searched for a shape pop-out target while ignoring a task-irrelevant color singleton distractor. Critically, targets and distractors could appear either along the vertical midline or at lateralized positions, allowing us to isolate and measure lateralized ERP activity related to targets or distractors. When the target appeared at lateralized positions (and the distractor on the vertical midline), a robust N2pc was observed, indicating selection of the target. However, when the distractor appeared at lateralized locations (and the target appeared on the midline) a reliable Pd was observed, indicating suppression of the distractor. This suggests that homologous mechanisms of distractor suppression operate in humans and nonhuman primates, and provides a basis for neurophysiological studies designed to determine the neural generators of the Pd component and distractor suppression during visual search.
Meeting abstract presented at VSS 2014