, Volume 52, Issue 1, pp 169-171
Date: 19 Nov 2008

Insulin effects on beta and theta activity in the human brain are differentially affected by ageing

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To the Editor: In peripheral tissues glucose uptake is established as a measure of insulin sensitivity, whereas the majority of glucose fluxes into the brain are insulin independent. However, at the level of neurons within the brain, insulin has been shown to modulate cell cycle, neurotransmitter production and electrical activity, and when insulin action fails, alterations in neuronal survival, food intake, body weight and determination of life-span occur. Based on these findings, insulin resistance of the brain is proposed to contribute to the development of obesity [1].

While peripheral insulin sensitivity is elevated in lean individuals, an increase in body weight impairs insulin-induced glucose uptake into peripheral tissues in obese individuals, and there is a strong correlation between insulin sensitivity and ageing in various animal models and humans. It should be noted that this correlation is largely dependent on an increase in body weight and alterations in body composition r