Affiliations: [a] Neuroimaging Laboratory, IRCSS Santa Lucia, Rome, Italy | [b] School of Life Sciences, University of Sussex, Brighton, United Kingdom | [c] Institute of Neurology, Università Cattolica, Rome, Italy | [d] Clinical Imaging Sciences Centre, Brighton and Sussex Medical School, Falmer, East Sussex, United Kingdom | [e] Department of Clinical Behavioural Neurology, IRCSS Santa Lucia Foundation, Rome, Italy | [f] Department of NeuroScience, University of Rome “Tor Vergata”, Rome, Italy
Correspondence:
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Correspondence to: Dr. Marco Bozzali, IRCCS Fondazione Santa Lucia, Via Ardeatina 306, 00179 Rome, Italy. Tel.: +39 06 5150 1324; Fax: +39 06 5150 1213; E-mail: m.bozzali@hsantalucia.it.
Abstract: One factor believed to impact brain resilience to the pathological damage of Alzheimer's disease (AD) is the so-called “cognitive reserve” (CR). A critical issue that still needs to be fully understood is the mechanism by which environmental enrichment interacts with brain plasticity to determine resilience to AD pathology. Previous work using PET suggests that increased brain connectivity might be at the origin of the compensatory mechanisms implicated in this process. This study aims to further clarify this issue using resting-state functional MRI. Resting-state functional MRI was collected for 11 patients with AD, 18 with mild cognitive impairment (MCI), and 16 healthy controls, and analyzed to isolate the default mode network (DMN). A quantitative score of CR was obtained by combining information about number of years of education and type of schools attended. Consistent with previous reports, education was found to modulate functional connectivity in the posterior cingulate cortex, whose disconnection with the temporal lobes is known to be critical for the conversion from MCI to AD. This effect was highly significant in AD patients, less so in patients with MCI, and absent in healthy subjects. These findings show the potential neural mechanisms underlying the individual's ability to cope with brain damage, although they should be treated with some caution based on small numbers.
