Figure 1.

Brain regions and experimental design. (a) Locations of the 2 brain regions (LIP and dlPFC) where the recordings were made. (b) Examples of the isolated cue and multi-item displays. The stimuli were 1.5° in size and were displayed 15° apart. The cue was either green or red and the distractors were the opposite color and the cue and the distractors were isoluminant. (c) An example of an experimental trial. Trials were initiated when a monkey fixated on a dot in the center of the screen. A cue, which consisted of either a single square displays on a blank background (isolated cue trial; not shown) or a square of one color with 8 other “distractor” squares of a different color (multi-item trial) was displayed for 500 ms. The monkey needed to remember the location of the cue and perform a delayed match to sample task on the cue location. All analyses in this article only examine data from the time when the cue display was displayed (i.e., data from time periods in the gray box were not analyzed).