Different activation patterns for working memory load and visual attention load

Abstract

Attention is a basic component of cognitition, and is modulated by cognitive load. We aimed to map the common network that supports attentional load across different tasks using functional magnetic resonance imaging (fMRI). Twenty-two healthy volunteers performed two sets of tasks with graded levels of cognitive load: verbal working memory (WM) and visual attention (VA) tasks. For both tasks, increased cognitive load (WM-load and VA-load) activated a common network comprising parietal and occipital cortices, thalamus, and the cerebellum, indicating that these brain regions are involved in higher level of attention. The fMRI signals in the prefrontal cortices increased with WMload but not with VA-load, suggesting that executive function is involved for the more demanding WM tasks but not for the more difficult VA tasks. Conversely, VA tasks activated more strongly an occipito-parietal network comprising the postcentral (PostCG) and the superior occipital (SOG) gyri, suggesting complex visual processing in this network.

Functional Alterations in Brain Activation and Deactivation in Mild Cognitive Impairment in Response to a Graded Working Memory Challenge

“…Inspection of significant activity revealed an extensive network of regions, including bilateral superior parietal lobe (BA 7), right occipital lobe (BA 18), bilateral cerebellar regions and right middle frontal lobe (BA 6), consistent with the distribution of brain regions responsive to visual WM load reported in previous studies [19,20,24,25], specifically those regions that typically show increased positive load-related responses. Regions such as the bilateral parietal cortex, medial parietal cortex, cingulate and medial frontal cortex that typically demonstrate negative load-related responses in young adults [46,63,64] were not observed, independent of group. A significant group × load interaction was observed in the right anterior cingulate (AC) for the encoding phase, but not for maintenance or retrieval.…”

Keeping Memory Clear and Stable--The Contribution of Human Basal Ganglia and Prefrontal Cortex to Working Memory

“…Increasing the number of items in a display, for example, also increases attentional load. Indeed, an fMRI study by Tomasi et al (2007) found that parietal cortex was driven both by cognitive load in an attention and memory task, whereas PFC was loaddriven only in the WM task. This may indicate that PFC is more specifically related to WM-an assumption also supported by the existing computational models of WM (Gruber et al, 2006;Hazy et al, 2006;O'Reilly and Frank, 2006).…”

Field dependence–independence as visuospatial and executive functioning in working memory: implications for instructional systems design and research

“…Brünken et al (2003) have provided helpful guidance for researchers who would like to use measures that are more direct, objective, and valid than measures typically used to this point in CLT investigations. Brünken and his colleagues note the potential for neuroimaging techniques (see Tomasi et al 2007 for a recent example) when it becomes more practical and better understood, but for the present they highlighted the benefits of the dual-task paradigm that is well known among working memory researchers. Essentially, dual task approaches involve using two tasks where one of the two tasks (e.g.…”