Functional differentiation of medial temporal and frontal regions involved in processing novel and familiar words: an fMRI studyстатья из журнала
Аннотация: Results of recent functional magnetic resonance imaging (fMRI) studies of memory are not entirely consistent with lesion studies. Furthermore, although imaging probes have identified neural systems associated with processing novel visual episodic information, auditory verbal memory using a novel/familiar paradigm has not yet been examined. To address this gap, fMRI was used to compare the haemodynamic response when listening to recently learned and novel words. Sixteen healthy adults (6 male, 10 female) learned a 10-item word list to 100% criterion, approximately 1 h before functional scanning. During echo-planar imaging, subjects passively listened to a string of words presented at 6-s intervals. Previously learned words were interspersed pseudo-randomly between novel words. Mean scans corresponding to each word type were analysed with a random-effects model using statistical parametric mapping (SPM96). Familiar (learned) words activated the right prefrontal cortex, posterior left parahippocampal gyrus, left medial parietal cortex and right superior temporal gyrus. Novel words activated the anterior left hippocampal region. The results for the familiar words were similar to those found in other functional imaging studies of recognition and retrieval and implicate the right dorsolateral prefrontal and left posterior medial temporal lobe (MTL) regions. The results for novel words require replication, but are consistent with the substantial lesion and PET literature implicating the anterior MTL as a critical site for processing novel episodic information, presumably to permit encoding. Together, these results provide evidence for an anterior-posterior functional differentiation within the MTL in processing novel and familiar verbal information. The differentiation of MTL functions that was obtained is consistent with a large body of PET activation studies but is unique among fMRI studies, which to date have differed from results with PET. Further, the finding of left MTL lateralization is consistent with lesion-based material-specific models of memory.
Год издания: 1999
Авторы: Andrew J. Saykin, Sterling C. Johnson, Laura A. Flashman, Thomas W. McAllister, Molly B. Sparling, Terrance M. Darcey, Chad H. Moritz, Stephen Guerin, John B. Weaver, Alexander C. Mamourian
Издательство: Oxford University Press
Источник: Brain
Ключевые слова: Functional Brain Connectivity Studies, Memory and Neural Mechanisms, Memory Processes and Influences
Открытый доступ: closed
Том: 122
Выпуск: 10
Страницы: 1963–1971