title: Medial temporal lobe activation during context-dependent relational processes in episodic retrieval: an fMRI study. Functional magnetic resonance imaging.
abstract: Previous studies have reported that the medial temporal lobe (MTL) structures contribute to the processing of relations among multiple stimuli in episodic encoding. There have been few studies, however, on the episodic retrieval requiring processing of relations among multiple components that was involved in our events. We used functional magnetic resonance imaging (fMRI) to investigate neural activities during the retrieval of relations within an organized episode and the recognition of an episodic component. Healthy, normal participants memorized 50 four-scene comic strips before fMRI scanning. In the retrieval phase with fMRI scanning, participants were engaged in three tasks: a visual identification (VI) task, a story recall (SR) task, and a picture recognition (PRe) task. In the VI task, participants were asked to judge whether they could identify at least one female character in the two scenes presented vertically. In the SR task, participants were shown the first and last scenes from strips memorized previously and asked to judge whether or not the two scenes were from the same strip. In the PRe task, participants were shown two scenes and asked to judge whether they both belonged to the memorized scenes. The two contrasts of SR with VI and PRe with VI demonstrated some commonly activated areas, such as the bilateral middle frontal gyrus and cerebellum. More importantly, the SR task differentially activated the bilateral parahippocampal gyrus, whereas the PRe task differentially activated right prefrontal areas, including the inferior frontal and precentral gyri. The results suggest that the activity of the MTL structures may be strongly associated with episodic memory retrieval requiring context-dependent relational processing.
authors.affiliation: Brain Architecture Analysis Group, Neuroscience Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan. t-tsukiura@aist.go.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Tsukiura
authors.forename: Toshikatsu
authors.initials: T
authors.lastname: Fujii
authors.forename: Toshimitsu
authors.initials: T
authors.lastname: Takahashi
authors.forename: Ruiting
authors.initials: R
authors.lastname: Xiao
authors.forename: Motoaki
authors.initials: M
authors.lastname: Sugiura
authors.forename: Jiro
authors.initials: J
authors.lastname: Okuda
authors.forename: Toshio
authors.initials: T
authors.lastname: Iijima
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yamadori
mesh_terms: D000328:Adult; D001931:Brain Mapping; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011939:Mental Recall / Q000502:physiology*; D011859:Radiography; D021641:Recognition, Psychology / Q000502:physiology; D013702:Temporal Lobe / Q000000981:diagnostic imaging / Q000502:physiology*