60 research outputs found
Observation of zwitterion formation in the gas-phase H/D-exchange with CH3OD: Solution-phase structures in the gas phase
Effet des activités sociales de loisirs sur la dénomination orale d'objets lors du vieillissement sain. Approche multimodale.
International audienc
Aging modulates fronto-temporal cortical interactions during lexical production. A dynamic causal modeling study
International audienceIn this dynamic causal modeling (DCM) study, we evaluated the effect of age on the effective connectivity of a cerebral network involved in lexical production. Younger and older adults performed an object naming task during fMRI. The DCM was used to explore the interactions between four regions of interest: the occipital cortex, OC; the lateral temporal cortex, LTC; the medial temporal cortex, MTC; and the inferior frontal cortex, IFC. We mainly focused on the modulation of the fronto-temporal interaction, according to the hypothesis that aging requires strategies that modulate the access to the semantic knowledge, either through a neural reserve mechanism (increased MTC-LTC connectivity) or through a neural compensation mechanism (supplementary IFC-MTC connectivity). For younger adults, our results indicated a bi-directional interaction between the left IFC and LTC suggesting a typical activation related to lexico-semantic representations. For older adults, our results reveal the existence of bi-directional interaction between the IFC and MTC, but not between the IFC and LTC – which in turn suggests that older adults adapt a new strategy, via supplemental access to conceptual access and semantic retrieval processes. This neural compensation strategy would be facilitated by a top-down mechanism from the IFC to the MTC. We discuss our results in the context of the possible additional strategies used by older compared to younger adults, to retrieve and produce words
Effect of the metal ion and the medium on the electronic structure of anthranilic acid: a modelling study on the Li and the BeH derivatives
Site Specificity in the Photooxidation of Some Trisubstituted Alkenes in Thionin-Supported Zeolite Na−Y. On the Role of the Alkali Metal Cation
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