Visuospatial Working Memory

Dispositional anxiety is a well-established risk factor for the development of psychiatric disorders along the internalizing spectrum, including anxiety and depression. Importantly, many of the maladaptive behaviors characteristic of anxiety, such as anticipatory apprehension, occur when threat is absent. This raises the possibility that anxious individuals are less efficient at gating threat’s access to working memory, a limited capacity workspace where information is actively retained, manipulated, and used to flexibly guide goal-directed behavior when it is no longer present in the external environment. Using a well-validated neurophysiological index of working memory storage, we demonstrate that threat-related distracters were difficult to filter on average and that this difficulty was exaggerated among anxious individuals. These results indicate that dispositionally anxious individuals allocate excessive working memory storage to threat, even when it is irrelevant to the task at hand. More broadly, these results provide a novel framework for understanding the maladaptive thoughts and actions characteristic of internalizing disorders.

Visuospatial bootstrapping is the name given to a phenomenon whereby performance on visually presented verbal serial-recall tasks is better when stimuli are presented in a spatial array rather than a single location. However, the display used has to be a familiar one. This phenomenon implies communication between cognitive systems involved in storing short-term memory for verbal and visual information, alongside connections to and from knowledge held in long-term memory. Bootstrapping is a robust, replicable phenomenon that should be incorporated in theories of working memory and its interaction with long-term memory. This article provides an overview of bootstrapping, contextualizes it within research on links between long-term knowledge and short-term memory, and addresses how it can help inform current working memory theory.

The impact of negative affect on working memory performance is unclear. Visuospatial and verbal working memory are critical in many settings, but may be impaired during exposure to negative stimuli. In Experiment 1, the impact of task-irrelevant negative picture stimuli on verbal compared to visuospatial working memory performance was investigated. Unexpectedly, visuospatial memory performance was superior for trials containing negative stimuli than trials with neutral stimuli. The impact of negative picture stimuli on visuospatial working memory was further examined in Experiment 2. Performance was again superior for negative stimuli relative to neutral stimuli. While much previous research has reported that negative affect is disruptive of visuospatial working memory, the improved performance found here is consistent with other research particularly where negative or arousing stimuli are thought to increase the pool of available processing resources or effort. Implications for contexts where working memory demands occur alongside distressing stimuli are discussed, as well as future research suggestions.

Background: Amnestic Mild Cognitive Impairment (MCIa) is a putative prodromal stage of Alzheimer's Disease (AD) characterized by focal deficits in episodic verbal memory. Relative deficits in visuospatial learning are not routinely considered to be a defining feature of MCIa, and yet ample human and animal evidence indicates both hippocampal involvement in visuospatial learning and both hippocampal degeneration and defective cholinergic neuro-transmission in early AD. Methods: This study sought to better characterize the components of spatial working memory dysfunction in MCIa participants (N 1⁄4 62), compared to healthy elderly adults (HE; N 1⁄4 94) using a hidden maze task. Results: Robust group differences were found (controlling for age and simple visuomotor speed) [F(1)1⁄44.9, p1⁄4.028] on the measure of spatial learning efficiency (exploratory errors), but both groups performed similarly on measures of spatial problem solving and reasoning. The learning curve between the first two learning trials was four times as steep for HE compared with MCIa (slope 1⁄4 4.9 vs. 1.24, respectively), indicating that MCIa participants exhibited relative difficulties in creating and making immediate effective use of an internal spatial map. Conclusions: MCIa patients demonstrated clear focal deficits in visuospatial working memory, with relative preservation of functioning on task measures of visuospatial reasoning and problem-solving.

Cette thèse prend pour objet un aspect peu étudié de la mémoire, la mémoire de travail visuo-spatiale et se donne comme objectif d’étudier le maintien à court terme des informations visuo-spatiales, comme il a été mis en évidence dans le maintien du matériel verbal (boucle phonologique). La partie théorique est une revue de questions sur la mémoire immédiate et notamment les aspects visuels et spatiaux de la mémoire. La partie empirique est réalisée à partir de plusieurs expériences sur l’adulte normal et s’appuie sur le paradigme des tâches interférentes. La première recherche pose un cadre général en dissociant expérimentalement les trois modules du modèle de Mémoire de Travail de Baddeley et Hitch (1974). Un second groupe de recherches vise à montrer la fonctionnalité d’un mécanisme de rafraîchissement visuo-spatial en mettant en évidence un effet longueur de parcours et les facteurs qui le soutiennent à travers la mise au point d'une tâche de mémoire immédiate visuo-spatiale peu usitée. Un troisième groupe de recherches teste le caractère général de l’effet longueur de parcours. Une dernière recherche teste le fonctionnement du mécanisme de rafraîchissement dans le cadre général de la Mémoire de Travail.