Interference control in healthy and pathological ageing

Age-associated cognitive decline is particularly pronounced in executive functions such as interference control - the ability to suppress the processing of irrelevant information. These deficits are also evident in patients with amnestic Mild Cognitive Impairment (aMCI), a preclinical phase of Alzheimer s dementia. In recent years, various studies have demonstrated that interference control consists of distinct subcomponents that are associated with different conflict tasks such as the Flanker conflict and the stimulus-response-conflict (SRC) task. Moreover, these subcomponents rely on distinct neural networks and exhibit specific temporal characteristics of neural processing. The present thesis investigates the effects of healthy and pathological ageing on different components of interference control. A combined Flanker and SRC task was conducted by young adults, healthy elderly and elderly with aMCI during electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) recording. Data analysis revealed that healthy elderly exhibit additional recruitment of fronto-parietal networks and increased modulation of the P2 component in response to incongruent information, probably as a compensatory mechanism. The deterioration of this effect in elderly with aMCI points to a decompensation in pathological ageing. Furthermore, the effects of healthy and pathological ageing on interference control are specific for different subcomponents, whereas SRC-related processing seems to be particularly susceptible to ageing effects.