Cerebrocortical Regions Associated with Implicit and Explicit Memory Retrieval Under the Conceptual Processing： BOLD Functional MR Imaging

Purpose： This study is to compare the distinct brain activation between implicit and explicit memory retrieval tasks using a non-invasive blood-oxygenation-level-dependent (BOLD) functional magnetic resonance imaging(fMRI). Materials ＆ Methods： We studied seven right-handed, healthy volunteers aged 21-25 years(mean；22 years) were scanned under a 1.5T Signa Horizon Echospeed MR imager(GE Medical Systems, Milwaukee, U.S.A.). During the implicit and explicit memory retrieval tasks of previously teamed words under the conceptual processing, we acquired fMRI data using gradient-echo EPI with 50ms TE, 3000ms TR, 26cm${\times}$26cm field-of-view, 128${\times}$128 matrix, and ten slices(6mm slice thickness, 1 mm gap) parallel to the AC-PC(anterior commissure and posterior commissure) line. By using the program of statistical parametric mapping(SPM99), functional activation maps were reconstructed and quantified.