title: Dissecting medial temporal lobe contributions to item and associative memory formation.
abstract: A fundamental and intensively discussed question is whether medial temporal lobe (MTL) processes that lead to non-associative item memories differ in their anatomical substrate from processes underlying associative memory formation. Using event-related functional magnetic resonance imaging, we implemented a novel design to dissociate brain activity related to item and associative memory formation not only by subsequent memory performance and anatomy but also in time, because the two constituents of each pair to be memorized were presented sequentially with an intra-pair delay of several seconds. Furthermore, the design enabled us to reduce potential differences in memory strength between item and associative memory by increasing task difficulty in the item recognition memory test. Confidence ratings for correct item recognition for both constituents did not differ between trials in which only item memory was correct and trials in which item and associative memory were correct. Specific subsequent memory analyses for item and associative memory formation revealed brain activity that appears selectively related to item memory formation in the posterior inferior temporal, posterior parahippocampal, and perirhinal cortices. In contrast, hippocampal and inferior prefrontal activity predicted successful retrieval of newly formed inter-item associations. Our findings therefore suggest that different MTL subregions indeed play distinct roles in the formation of item memory and inter-item associative memory as expected by several dual process models of the MTL memory system.
authors.affiliation: Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, 6500 HB Nijmegen, The Netherlands. shaozheng.qin@donders.ru.nl
authors.forename: Shaozheng
authors.initials: S
authors.lastname: Qin
authors.forename: Mark
authors.initials: M
authors.lastname: Rijpkema
authors.forename: Indira
authors.initials: I
authors.lastname: Tendolkar
authors.forename: Carinne
authors.initials: C
authors.lastname: Piekema
authors.forename: Erno J
authors.initials: EJ
authors.lastname: Hermans
authors.forename: Marek
authors.initials: M
authors.lastname: Binder
authors.forename: Karl Magnus
authors.initials: KM
authors.lastname: Petersson
authors.forename: Jing
authors.initials: J
authors.lastname: Luo
authors.forename: Guillén
authors.initials: G
authors.lastname: Fernández
mesh_terms: D001245:Association Learning / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008568:Memory / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology*; D013702:Temporal Lobe / Q000502:physiology*; D055815:Young Adult