L’Encéphale, 2006 ; 32 : 253-62, cahier 1 253 NEUROPSYCHOLOGIE Existe-t-il un déficit d’inhibition lors du vieillissement ? Confrontation de l’hypothèse dorso-ventrale et de l’hypothèse frontale dans l’effet d’amorçage négatif S. MARTIN (1) , D. BROUILLET (2, 3) , E. GUERDOUX, R. TARRAGO (1) sophiesmr@aol.com. (2) Laboratoire de Psychologie Expérimentale de la Mémoire et de la Cognition (LaMeCo), EA 3021, Université Paul-Valéry, Route de Mende, 34199 Montpellier cedex 05. (3) denis.brouillet@univ-mont3.fr Travail reçu le 21 juin 2004 et accepté le 17 décembre 2004. Tirés à part : S. Martin (à l’adresse ci-dessus). Inhibition and resource capacity during normal aging : a confrontation of the dorsal-ventral and frontal models in a modified version of negative priming Background. Over the past decades, cognitive psychology contribution to our understanding of aging relies on two major perspectives, focusing on the selective impact of age on either cognitive multiple-systems or global factors of cognition : slowing, working memory and inhibition. In the latter, reduction in inhibitory control during aging (in its access, deletion or restraint functions) is associated with poorer performance on a variety of tasks referring to memory, comprehension or language [Hasher, Zacks and May (16)]. The attractiveness of inhibition as an explanatory factor results in part in the absence of negative priming during aging. Negative priming refers to the slow down of latencies when individuals have to respond to recently ignored informations, compared to unrelated informations. The dissociation, between a preserved location negative priming and an absence of identity negative priming during aging, supports the dorsal-ventral model of inhibition which suggests that spatial and identity inhibition are supported by different and independent visual pathways. An alternative model, directly at odds, is that inhibitory mechanisms are supported by the frontal lobe. In this perspective, inhibition is not a central process responsible for the control of working memory contents, but an automatic and local mechanism whose triggering depends on controlled attention. Therefore, working memory drives efficient inhibition by sustaining task instructions and appropriate responses throughout task execution. This hypothesis is consistent with Hough- ton and Tipper’s (17) architecture of selective attention. According to the authors, the presence or absence of automatic inhibition is very closely linked to a Match/Mismatch field whose function is to compare the present stimulus to an internal self-generated internal template. When an information fails to match the subject’s current goals, the match/mismatch field causes an automatic inhibitory imbalance which reduces the to-be-ignored properties’ responsiveness. In contrast, information matching subjects’ goal is enhanced through an automatic excitatory imbalance. The accurate functioning of the Match/Mismatch field requires efficient executive functioning responsible for the uphold of goals and correct responses. In the case of negative priming, manipulating the efficiency of working memory is of interest as it should affect the triggering of slowing, ie, an indirect inhibitory deficit, when the task is resource demanding [Conway et al. (6)]. Moreover, if inhibition, as reflected by negative priming, is mediated by individual resource capacity, then NP should disappear during aging only when individuals are engaged in a resource-demanding task. Objectives. To address this issue, we examine whether cognitive control load in a gender decision task contributed to the presence or absence of NP during aging. According to the dorsal-ventral model, task complexity should not have any impact on performance, since gender decision task relies on a conceptual analysis of information. In turn, the frontal model predicts that age differences in performance profile will only differ when individual resource capacity is overloaded. Design of the study. Sixty-four participants (32 young and 32 older adults) performed a gender categorisation task through two experiments. Trials involved two stimuli presented successively at the same location. A word served as a prime and a word as a target. Both prime and target