Interference resolution in spatial working memory.

Anterior cingulate and lateral inferior prefrontal cortex (PFC) are considered important for conflict monitoring and interference resolution in many verbal tasks. We studied interference resolution in a spatial working memory task using event-related fMRI. The task required participants to ignore two locations from a set of four initially held in working memory and to remember the remaining two locations as the target set for a subsequent recognition test. Familiarity of nontarget probes was manipulated by drawing the probe from either the ignored locations [high familiarity (HF)] or locations not used in the present trial [low familiarity (LF)]. Precentral sulcus (PrCS) and superior parietal lobe (SPL), two regions commonly associated with motor planning and spatial attention, showed heightened activity in response to increased level of interference from nontargets of high familiarity. Our finding suggests that interference resolution in the spatial domain may involve a different subset of the working memory system from that in the verbal domain.