title: Studying memory encoding to promote reliable engagement of the medial temporal lobe at the single-subject level.
abstract: The medial temporal lobe (MTL)—comprising hippocampus and the surrounding neocortical regions—is a targeted brain area sensitive to several neurological diseases. Although functional magnetic resonance imaging (fMRI) has been widely used to assess brain functional abnormalities, detecting MTL activation has been technically challenging. The aim of our study was to provide an fMRI paradigm that reliably activates MTL regions at the individual level, thus providing a useful tool for future research in clinical memory-related studies. Twenty young healthy adults underwent an event-related fMRI study consisting of three encoding conditions: word-pairs, face-name associations and complex visual scenes. A region-of-interest analysis at the individual level comparing novel and repeated stimuli independently for each task was performed. The results of this analysis yielded activations in the hippocampal and parahippocampal regions in most of the participants. Specifically, 95% and 100% of participants showed significant activations in the left hippocampus during the face-name encoding and in the right parahippocampus, respectively, during scene encoding. Additionally, a whole brain analysis, also comparing novel versus repeated stimuli at the group level, showed mainly left frontal activation during the word task. In this group analysis, the face-name association engaged the HP and fusiform gyri bilaterally, along with the left inferior frontal gyrus, and the complex visual scenes activated mainly the parahippocampus and hippocampus bilaterally. In sum, our task design represents a rapid and reliable manner to study and explore MTL activity at the individual level, thus providing a useful tool for future research in clinical memory-related fMRI studies.
authors: Cognition and Brain Plasticity Group, Bellvitge Biomedical Research Institute-IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain; Neuro-Oncology Unit, Hospital Universitari de Bellvitge (HUB) and Hospital Duran i Reynals (Institut Català d'Oncologia), L'Hospitalet de Llobregat, Barcelona, Spain.
authors: Marta
authors: M
authors: Simó
authors: Cognition and Brain Plasticity Group, Bellvitge Biomedical Research Institute-IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain; Department of Basic Psychology, Bellvitge Campus, University of Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.
authors: Pablo
authors: P
authors: Ripollés
authors: Cognition and Brain Plasticity Group, Bellvitge Biomedical Research Institute-IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain; Department of Basic Psychology, Bellvitge Campus, University of Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.
authors: Lluís
authors: L
authors: Fuentemilla
authors: Cognition and Brain Plasticity Group, Bellvitge Biomedical Research Institute-IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain; Department of Basic Psychology, Bellvitge Campus, University of Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.
authors: Lucía
authors: L
authors: Vaquero
authors: Neuro-Oncology Unit, Hospital Universitari de Bellvitge (HUB) and Hospital Duran i Reynals (Institut Català d'Oncologia), L'Hospitalet de Llobregat, Barcelona, Spain.
authors: Jordi
authors: J
authors: Bruna
authors: Cognition and Brain Plasticity Group, Bellvitge Biomedical Research Institute-IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain; Department of Basic Psychology, Bellvitge Campus, University of Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain; Catalan Institution for Research and Advanced Studies, ICREA, Barcelona, Spain.
authors: Antoni
authors: A
authors: Rodríguez-Fornells
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods; D005260:Female; D006624:Hippocampus / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008568:Memory / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology; D013702:Temporal Lobe / Q000502:physiology*