Introduction to age-related cognitive-behavioural changes

As individuals age, they undergo both biological and physiological changes that are apparent and expected. Another often overlooked aspect of senescence are the changes in cognition and behaviour. These are often misunderstood or complicated with common neurodegenerative disorders found in the elderly. This chapter acts as an introduction into these cognitive-behavioural changes. There are a variety of methodologies currently employed in the investigation of these changes, such as functional magnetic resonance imaging, electroencephalography, and animal studies. Novel methodologies are being deployed for the analysis of gut-flora interactions with the CNS and how they may impact behavioural changes as our microbiota changes in late-life. Multiple modulatory factors are at play as well, further complicating the multifaceted nature of ageing cognition differences. Sex and genetics are major factors that are associated with age-related behavioural changes. Gross structural and molecular changes in the CNS are also associated with pronounced changes in cognition. Low-grade chronic inflammation, epigenetics and infections also seem to be significant. Neurodegenerative diseases, whilst pathological, work in tandem with natural ageing and present age-related changes in behaviour. The most common changes are summarised and the expression of the previously discussed modulatory factors are presented.