A Right Hemisphere Role in Cognitive Reserve

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Abstract High levels of education, occupational complexity and/or premorbid intelligence are associated with lower levels of cognitive impairment than would be expected from a given brain pathology. This has been observed across a range of conditions including Alzheimer's Disease protect the brain from expressing symptoms of damage, has been termed 'cognitive reserve' (Stern, 2012). The current review considers one possible neural network which may contribute to cognitive reserve. Based on evidence that the neurotransmitter noradrenaline mediates cognitive reserve's protective effects (Robertson, 2013) this review identifies the neuro-cognitive correlates of noradrenergic (NA) activity. These involve a set of interrelated cognitive processes (arousal, sustained attention, response to novelty and awareness) with a strongly right hemisphere, fronto-parietal localization, along with working memory which is also strongly modulated by NA. It is proposed that this set of processes is one plausible candidate for partially mediating the protective effects of cognitive reserve. In addition to its biological effects on brain structure and function, NA function may also facilitate networks for arousal, novelty, attention, awareness and working memory which collectively provide for a set of additional, cognitive, mechanisms that help the brain adapt to age-related changes and disease. It is hypothesized that to the extent that the lateral surface of the right prefrontal lobe and/or the right inferior parietal lobe maintain structural (white and grey matter) and functional integrity and connectivity, cognitive reserve should benefit and behavioral expression of pathological damage should thus be mitigated.