Structural and functional cerebral bases of diminished inhibitory control during healthy aging

Abstract

Inhibitory control or the ability to refrain from incorrect responses is a critical executive function known to diminish during aging. Imaging studies have elucidated cerebral changes that may underlie the age-related deficits. However, it remains unclear whether the structural and functional changes occur in the same brain regions and whether reduced gray matter volumes (GMV) mediate decreased activation during inhibition. Here, in a sample of 149 participants, we addressed the issues using structural and functional magnetic resonance imaging. Individual's response inhibition was evaluated by the stop signal reaction time (SSRT) in a stop signal task. The results showed that age was associated with prolonged SSRT across participants. Many cortical and subcortical regions demonstrated age-related reduction in GMV and activation to response inhibition. Additionally, age-related diminution in inhibitory control, as indexed by the SSRT, was associated with both shared and distinct morphometric and functional changes. Voxel-based morphometry demonstrated age-related reduction in GMV in the right dorsolateral prefrontal cortex and caudate head as well as bilateral insula, in association with prolonged SSRT. In a contrast of stop success versus go success trials, age was associated with lower activation in the medial and inferior frontal cortex and inferior parietal cortex. Further, reduction in GMV mediated age-related differences in activations only of the medial prefrontal cortex, providing limited evidence for structure function association. Thus, the decline in inhibitory control, as evidenced in the stop signal task, manifest with both shared and distinct structural and functional processes during aging.

Is the Discrimination of Subjective Cognitive Decline from Cognitively Healthy Adulthood and Mild Cognitive Impairment Possible? A Pilot Study Utilizing the R4Alz Battery

“…Even though it was under debate whether inhibition and switching are age-related abilities, according to our study, both abilities seem to change during lifespan. Our study comes to an agreement with others that show a decrease in activation of inhibitory control [70] and switching as well [71]. Therefore, ICT/RST-S1&S2 and ICT/RST-FS in consistency with the age-relation literature, can differentiate the SCD people from the HYA and HMaA.…”

Brain Structure and Subclinical Symptoms: A Dimensional Perspective of Psychopathology in the Depression and Anxiety Spectrum

“…Under pathological conditions including atrophy, lower GMV is commonly assumed to lead to decreased function, because it is mostly found in functionally impaired subjects, i.e. in patients or in the aging brain [69]. A positive association of subclinical symptoms with GMV as in some of the mentioned studies appears less intuitive.…”

Imaging the effects of age on proactive control in healthy adults

“…For example, in behavioral paradigms to examine conflict monitoring and resolution, such as the go/no-go, flanker, Stroop, and stop signal task (SST), participants not only adjust behavior according to the stimuli but also anticipate behavioral adjustment according to what they have learned from the tasks. We previously showed that the efficiency of reactive control in the SST diminished with age, as reflected by longer stop signal reaction time (SSRT), and was associated with reduced activations in the medial prefrontal cortex and right inferior frontal gyrus pars opercularis/anterior insula in older adults (Hu et al 2018). The current work aimed to investigate age-related changes in proactive control and whether these changes may influence reactive control in the SST.…”

“…Second, we investiageted the neural mechanisms relating proactive to reactive control and specifically how regional activations to conflict anticipation may influence the SSRT. As age was associated with longer SSRT (Hu et al 2012; Hu et al 2018) and cerebral responses to proactive control have been related to SSRT (Hu et al 2016), we hypothesized that regional activations and FC in support of proactive control did not benefit reactive response inhibition, as indexed by SSRT, during aging.…”