title: Hippocampal functional magnetic resonance imaging during a face-name learning task in adolescents with antecedents of prematurity.
abstract: Functional magnetic resonance imaging (fMRI) was used to map hippocampal activation during a declarative memory task in a sample of 14 adolescents with antecedents of prematurity (AP). The sample with AP was matched by age, sex and handedness with 14 full-term controls with no history of neurological or psychiatric illness. The target task consisted in learning 16 novel face-name pairs, and the control task involved the examination of two repeated face-name pairs. Stereological methods were also used to quantify hippocampal volumes. In both groups, we observed increased activation in the learning condition compared to the control task in the right fusiform gyrus and the left inferior occipital gyrus, but only premature subjects activated the hippocampus. Group comparison of the activation versus control conditions showed that prematures had greater activity in the right hippocampus than controls during the encoding of the word-face association. Volumetric analyses showed a significant left hippocampal volume loss in adolescents with AP. In addition, we found a significant positive correlation in the premature group between right hippocampal activation and face-name recognition. Functional MRI data also correlated with structural MRI data: right hippocampal activation correlated positively with right hippocampal volume. Our findings are consistent with previous studies of brain plasticity after focal lesions. Left hippocampal tissue loss may be related to an increase in contralateral brain activity, probably reflecting a compensatory mechanism. Our data also suggest that this plasticity is not enough to achieve normal performance.
authors.affiliation: Department of Psychiatry and Clinical Psychobiology, Faculty of Medicine, University of Barcelona, Spain.
authors.forename: Mónica
authors.initials: M
authors.lastname: Giménez
authors.forename: Carme
authors.initials: C
authors.lastname: Junqué
authors.forename: Pere
authors.initials: P
authors.lastname: Vendrell
authors.forename: Xavier
authors.initials: X
authors.lastname: Caldú
authors.forename: Ana
authors.initials: A
authors.lastname: Narberhaus
authors.forename: Núria
authors.initials: N
authors.lastname: Bargalló
authors.forename: Carles
authors.initials: C
authors.lastname: Falcón
authors.forename: Francesc
authors.initials: F
authors.lastname: Botet
authors.forename: Josep Maria
authors.initials: JM
authors.lastname: Mercader
mesh_terms: D000293:Adolescent; D005145:Face; D005260:Female; D006624:Hippocampus / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007858:Learning / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D009275:Names