The classical backward digit span task detects changes in working memory but is unsuitable for classifying the severity of dementia

A meta-analysis on the relationship between subjective cognitive failures as measured by the cognitive failures questionnaire (CFQ) and objective performance on executive function tasks

The Cognitive Failures Questionnaire (CFQ) has been widely used as a measure of subjective cognitive function in everyday life for decades. However, the evidence on how it relates to objective performance on executive function tasks is mixed. One possible reason for these mixed results is that the CFQ has selective relationships with some aspects of executive function and not others. Here, therefore, we classified tasks according to an influential framework of executive functions-switching, updating, inhibition, and we also considered the Sustained Attention to Response Task (SART) as a category because it was custom designed to gauge cognitive failures. We synthesized a large body of available evidence and performed four Bayesian meta-analyses on the relationship between CFQ scores and objective performance on executive function tasks in these four categories. Results suggested that CFQ scores were associated with objective performance on SART (18 effect sizes, μ = -.19, BF10 = 18.03, i.e., 18.03 times more evidence of a relationship versus no relationship), updating working memory (49 effect sizes, μ = -.06, BF10 = 17.80), and inhibition tasks (41 effect sizes, μ = -.07, BF10 = 15.40), whereas there was not definitive evidence regarding switching (34 effect sizes, μ = -.06, BF10 = .50, i.e., two times greater evidence for no relationship). This suggests that subjective cognitive function can predict objective performance on at least some executive function tasks. We discuss methodological and theoretical factors that constrain the maximum observable correlation and consider the relative insights that subjective measures versus task performance provide.

Restorative Effects of Observing Natural and Urban Scenery after Working Memory Depletion

According to attention restoration theory observing nature has restorative effects on cognitive components, such as working memory, after a cognitive depleting task. Additionally, urban environments are thought to have no effect or even a negative effect on cognitive restoration. Previous research has confirmed that observing actual, as well as digitally presented nature sceneries leads to more restoration of working memory capacity (WMC) than observing (digital) urban sceneries. To further investigate these findings, we conducted an experiment with 72 university students as participants. After a WMC depleting task, participants observed either digitally presented nature scenery, urban scenery or no scenery, and subsequently performed a digit span test, which was used to measure restoration of WMC. Results indicated significant higher performance on the digit span test for those who observed nature scenery in comparison to those who observed urban scenery or no scenery, thereby replicating results from previous research. Observing urban scenery was neither harmful nor helpful in terms of cognitive restoration compared to observing no scenery. These findings provide a foundation for implementing a brief intervention of observing nature in academic settings to facilitate the restoration of WMC.

Compensatory thalamocortical functional hyperconnectivity in type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is associated with brain damage and cognitive decline. Despite the fact that the thalamus involves aspects of cognition and is typically affected in T2DM, existing knowledge of subregion-level thalamic damage and its associations with cognitive performance in T2DM patients is limited. The thalamus was subdivided into 8 subregions in each hemisphere. Resting-state functional and structural MRI data were collected to calculate resting-state functional connectivity (rsFC) and gray matter volume (GMV) of each thalamic subregion in 62 T2DM patients and 50 healthy controls. Compared with controls, T2DM patients showed increased rsFC of the medial pre-frontal thalamus, posterior parietal thalamus, and occipital thalamus with multiple cortical regions. Moreover, these thalamic functional hyperconnectivity were associated with better cognitive performance and lower glucose variability in T2DM patients. However, there were no group differences in GMV for any thalamic subregions. These findings suggest a possible neural compensation mechanism whereby selective thalamocortical functional hyperconnectivity facilitated by better glycemic control help to preserve cognitive ability in T2DM patients, which may ultimately inform intervention and prevention of T2DM-related cognitive decline in real-world clinical settings.