Year: 2011
Type: dissertation
Abstract: Healthy ageing has been found to be accompanied by changes in slow wave activity (SWA) and cognitive function. Furthermore, these changes have been seen predominantly in the prefrontal cortex (PFC) compared to\nother regions of the cortex. Current theories of cognitive ageing propose that\nthis occurs due to a specified deterioration of neuronal substrates of the\nPFC, and as such, changes in SWA and cognitive function may decline at\nsimilar rates due to similar underlying aetiology.\nThe main aim of the current thesis was to explore age-related differences in\nelectroencephalographic (EEG) SWA during the first NREM period and\ncognitive performance that relies on the integrity of the PFC: executive\nfunction and social cognition. The extent to which executive function (reliant\non dorsolateral PFC areas) and social cognitive function (reliant on\nventromedial PFC regions) show similar age-related deterioration was\ninvestigated in Study 1. Here, 16 young (22.2 years) and 16 older (71.5\nyears) adults were administered with a cognitive testing battery including\nexecutive function measures: Verbal Fluency (VF) and Tower of London\n(TOL); as well as measures of social cognition: Go/No-go, Emotional\nProsody and Ekman 60 Faces. Not all measures of PFC function were\naffected to the same extent. The older group performed significantly worse\non the TOL, but not on the VF test. Additionally, simple aspects of social\ncognition did not display differences between the groups, but the older\ngroup performed significantly worse than the young group on more complex\naspects of recognition of emotion from facial expression (Ekman 60 Faces)\nand Emotional Prosody.\nAs most studies of cognitive ageing are cross-sectional and show large agerelated\nchanges, the remainder of this thesis focused on age-related\nchanges using a longitudinal design over a relatively small ageing period\n(mean = 6.29 years). The average age of participants at baseline was 67.1\nyears and the average age at follow-up was 73.4 years. In Study 2, in a\nsample of 11 participants, performance on executive function tests was\nmeasured (TOL, VF and Wisconsin Card Sorting Test: WCST). As found in\nthe cross-sectional analyses reported in Study 1, the TOL task was found to\nbe the most sensitive indicator of age-related changes, as this showed a\ndecline with age; whereas, VF and WCST remained stable over time.\nFurthermore, in Study 3, localised SWA was recorded via EEG, and significant declines were found in low frequency delta (0.5 – 1 Hz), which was localised to the left frontal region. (Continues...).
Author: Clare E. Webb
Language: English
Subfield: Cognitive Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W772053929