Neural correlates of episodic retrieval success

Episodic memory retrieval involves multiple component processes, including those that occur when information is correctly remembered (retrieval succes s). The present study employed rapid-presentation event-related functional MRI that allowed different trial types with short intertrial intervals to b e sorted such that the hemodynamic response associated with retrieval succe ss could be extracted. Specifically, in an old/new episodic recognition tas k, hit trials (correctly recognized old items) and correct rejection trials (correctly rejected new items) were directly compared. The comparison reve aled a mostly left-lateralized set of brain regions. Differential activatio n was most robust in left lateral parietal cortex and medial parietal corte x. Additional regions of differential activation included left anterior pre frontal cortex at or near Brodmann area 10, anterior insula, thalamus, ante rior cingulate cortex, frontal cortex along inferior frontal gyrus, premoto r cortex, and presupplementary motor area. These results suggest that left frontal and parietal regions modulate activity based on the successful retr ieval of information from episodic memory. We discuss these findings in the context of several recent investigations that provide converging results a s well as prior studies that have failed to detect these changes. (C) 2000 Academic Press.