Neural correlates of strategic memory retrieval: Differentiating between spatial-associative and temporal-associative strategies

Remembering complex, multidimensional information typically requires strategic memory retrieval, during which information is structured, for instance by spatial‐ or temporal associations. Although brain regions involved in strategic memory retrieval in general have been identified, differences in retrieval operations related to distinct retrieval strategies are not well‐understood. Thus, our aim was to identify brain regions whose activity is differentially involved in spatial‐associative and temporal‐associative retrieval. First, we showed that our behavioral paradigm probing memory for a set of object‐location associations promoted the use of a spatial‐associative structure following an encoding condition that provided multiple associations to neighboring objects (spatial‐associative condition) and the use of a temporal‐associative structure following another study condition that provided predominantly temporal associations between sequentially presented items (temporal‐associative condition). Next, we used an adapted version of this paradigm for functional MRI, where we contrasted brain activity related to the recall of object‐location associations that were either encoded in the spatial‐ or the temporal‐associative condition. In addition to brain regions generally involved in recall, we found that activity in higher‐order visual regions, including the fusiform gyrus, the lingual gyrus, and the cuneus, was relatively enhanced when subjects used a spatial‐associative structure for retrieval. In contrast, activity in the globus pallidus and the thalamus was relatively enhanced when subjects used a temporal‐associative structure for retrieval. In conclusion, we provide evidence for differential involvement of these brain regions related to different types of strategic memory retrieval and the neural structures described play a role in either spatial‐associative or temporal‐associative memory retrieval. Hum Brain Mapp 2008. © 2007 Wiley‐Liss, Inc.