Figure 1.

Working memory task. Rows depict three key conditions from the lateralized change detection (i.e., working memory) task (from top to bottom: NT1, NT1FT1, NT1FD1). As detailed in the Methods section, lateralized presentation was necessary for isolating contralateral delay activity (CDA). Attention was directed to one hemifield by the arrow cues; identical stimuli were presented in the uncued hemifield to control for non-specific perceptual and preparatory motor activity when calculating CDA. Delay-spanning CDA was extracted from the 900 ms delay epoch. For ease of interpretation, the schematic is not to scale. Portions of this figure were reprinted by permission from Macmillan Publishers Ltd.: Nature Reviews Neuroscience (Houdé and Tzourio-Mazoyer, 2003; Peelen and Downing, 2007).