Distinct aspects of frontal lobe structure mediate age-related differences in fluid intelligence and multitasking

Abstract

Ageing is characterized by declines on a variety of cognitive measures. These declines are often attributed to a general, unitary underlying cause, such as a reduction in executive function owing to atrophy of the prefrontal cortex. However, age-related changes are likely multifactorial, and the relationship between neural changes and cognitive measures is not well-understood. Here we address this in a large (N=567), population-based sample drawn from the Cambridge Centre for Ageing and Neuroscience (Cam-CAN) data. We relate fluid intelligence and multitasking to multiple brain measures, including grey matter in various prefrontal regions and white matter integrity connecting those regions. We show that multitasking and fluid intelligence are separable cognitive abilities, with differential sensitivities to age, which are mediated by distinct neural subsystems that show different prediction in older versus younger individuals. These results suggest that prefrontal ageing is a manifold process demanding multifaceted models of neurocognitive ageing.

The neural determinants of age-related changes in fluid intelligence: a pre-registered, longitudinal analysis in UK Biobank

“…However, this effect was very small (standardized path=-0.06), especially compared to previously reported effects (e.g. r=-0.7, Kievit et al , 2014). The pattern of results for the slopes was unexpected.…”

Retiring the Central Executive

“…Johnson, Logie & Brockmole, 2010;Kievet, Davis, Mitchell, Taylor, Duncan, Cam-CAN Research Team & Henson, 2014;Park, Lautenschlager, Hedden, Davidson, Smith & Smith, 2002;Park & Reuter-Lorenz, 2009), and this is compatible with the view that there are multiple specialised functions that are differentially sensitive to age. So, the idea that there are multiple functions that previously might have been considered to be supported by an executive homunculus, is being replaced by multiple cognitive processes, each of which serves a specific function, with performance perhaps constrained by the effectiveness of neural communication.…”

The Association of Specific Executive Functions and Falls Risk in People with Mild Cognitive Impairment and Early-Stage Dementia

“…Kievit, Davis, Mitchell et al [15] demonstrated that multitasking and fluid intelligence, which are both considered part of executive function [7] are distinguishable cognitive abilities with fluid intelligence but not multitasking related to grey matter volume in one particular area of the prefrontal cortex (Brodmann Area 10). In addition, performance in multitasking but not fluid intelligence was related to white matter intensities in the Anterior Thalamic Radiation area.…”

“…For example, Lefleche and Albert [13] showed that in people with mild Alzheimer's disease (AD), the ability to complete mental set shifting, self-monitoring or sequencing tasks was significantly impaired in comparison to people without AD, while the ability to solve verbal problem tests was not impaired. Executive function is associated with prefrontal cortex activity and, depending on executive function task, different neural subsystems are involved [14,15].…”