The cerebellum in thought and action: A fronto-cerebellar aging hypothesis

Normal aging is associated with deficits in both memory and executive control. While a number of theories of cognitive aging have proposed that decrements in frontally mediated executive control processes can account for many of the age-related changes observed, the models proposed to date have not adequately accounted for age changes in processing speed, intra-individual variability and automaticity of information processing. These basic aspects of information processing efficiency may be of central importance for our understanding of age-related cognitive changes and more elaborate neurological models are needed that incorporate explanatory mechanisms which account for their influence. In this paper, it is proposed that the dual role played by frontal and cerebellar degeneration and the disruption of fronto-cerebellar feedback and feedforward control loops may be of central importance for a model of age-related changes in processing speed, intra-individual variability, automaticity, and higher level cognitive functions like memory and executive control.