Los mecanismos inhibitorios en el nombrado y reconocimiento de carasíndices evolutivos y neurales

Abstract

As people get older, several cognitive functions start to suffer from age-related changes in the brain. One of the complaints reported more often by older adults is their inability to learn new names and to recall names of well-known people in their lives. Since this deficit has a considerable impact in seniors' lives (eliciting negative moods and generating a lack of self-confidence on their own linguistic capacities), and given that naming difficulties could help distinguishing between Mild Cognitive Impairment and healthy aging, it is deemed important to understand what mechanisms underlie these naming difficulties. In this work, we hypothesized that controlled inhibitory mechanisms could help explaining this deficit and in order to test this hypothesis, we conducted four experimental series that try to assess i) if personal representations (such as faces and names) are vulnerable to controlled inhibitory mechanisms? If so, ii) what are the neural correlates of this effect? And iii) how does this effect and its neural correlates change with normal aging? Results revealed that personal representations suffer, at least in some instances, from the same inhibitory mechanisms as other types of object. These mechanisms act upon representations that compete for retrieval, as tested by the retrieval practice paradigm and its effect of Retrieval Induced Forgetting (RIF). Additionally, we found that RIF's neural correlates are maintained in younger adults when using facial stimuli, but that these change as a function of aging. Concretely, our results indicate that RIF effect is hindered in older adults at a behavioral level and that this impairment is accompanied by less engagement of frontal brain regions, such as the anterior cingulate cortex or the lateral prefrontal cortex. Thus, our results indicate that naming difficulties could be due to a deficit in inhibitory mechanisms, which strongly supports the Inhibitory Deficit Theory.