The regulation of cognitive activity relies on the flexibility of prefrontal cortex functions. To study this mechanism we compared monkey dorsolateral prefrontal activity in two different spatial cognitive tasks: a delayed response task and a self-organized problem-solving task. The latter included two periods, a search by trial and error for a correct response, and a repetition of the response once discovered. We show that (1) delay activity involved in the delayed task also participates in self-generated responses during the problem-solving task and keeps the same location preference, and (2) the amplitude of firing and the strength of spatial selectivity vary with task requirement, even within search periods while approaching the correct response. This variation is dissociated from pure reward probability, but may have a link with uncertainty because the selectivity dropped when reward predictability was maximal. Overall, we show that spatially tuned delay activity of prefrontal neurons reflects the varying level of engagement in control between different spatial cognitive tasks and during self-organized behavior.