Activity of prefrontal neurons during location and color delayed matching tasks

MANY cells in prefrontal cortex show enhanced activity prior to movement on set in delayed or memory-guided saccade tasks. This activity is a possible neural correlate of spatial attention and working memory. The goal of this study was to determine whether delay activity is evoked when non-spatial cu es such as color are used to guide saccades. Monkeys were trained on a sacc ade target selection task in which they were cued for either the location o r color of the rewarded target. When the location of the target was specifi ed explicitly, many cells showed visual responses and delay activity that w ere spatially selective. Color selective visual responses or delay activity were both rare and weak. However, for many cells, spatially selective dela y activity could be evoked when color was used to specify the location of t he target. These results indicate that color is capable of eliciting spatia lly selective activity from cells that have no overt color selectivity. (C) 1999 Lippincott Williams & Wilkins.