Regional activation of the human medial temporal lobe during intentional encoding of objects and positions

Thomas Z. Ramsoy, Matthew George Liptrot, Arnold Jesper Møller Skimminge, Torben E. Lund, Karam Sidaros, Mark Schram Christensen, William Baare, Olaf B. Paulson, Terry Jernigan

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The medial temporal lobe (MTL) consists of several regions thought to be involved in learning and memory. However, the degree of functional specialization among these regions remains unclear. Previous studies have demonstrated effects of both content and processing stage, but findings have been inconsistent. In particular, studies have suggested that the perirhinal cortex is more involved in object processing than spatial processing, while other regions such as the parahippocampal cortex have been implicated in spatial processing. In this Study, functional magnetic resonance imaging (fMRI) optimized for the MTL region was used to probe MTL activation during intentional encoding of object identities or positions. A region of interest analysis showed that object encoding evoked stronger activation than position encoding in bilateral perirhinal cortex, temporopolar cortex, parahippocampal cortex, hippocampus and amygdala. Results also indicate an unexpected significant Correlation in activation level between anterior and posterior portions in both the left parahippocampal cortex and left hippocampus. Exploratory analysis did not show any regional content effects during preparation and rehearsal stages. These results provide additional evidence for functional specialization within the MTL, but were less clear regarding the specific nature of content specificity in these regions. (C) 2009 Elsevier Inc. All rights reserved.
Original languageEnglish
JournalNeuroImage
Volume47
Issue number4
Pages (from-to)1863-1872
ISSN1053-8119
DOIs
Publication statusPublished - 2009
Externally publishedYes

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