Recruitment of extra neural resources may allow people to maintain normal cognition despite amyloid-beta plaques. Previous fMRI studies have reported such hyperactivation, but it has been unclear whether such increases represent compensation or aberrant overexcitation. In this study, Elman and colleagues have found that older adults with amyloid-beta deposition had reduced deactivations in task-negative regions, but increased activation in task-positive regions related to more detailed memory encoding. They suggest that the association between higher activity and more detailed memories means that amyloid-beta-related hyperactivation is compensatory.
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Elman JA, Oh H, Madison CM, Baker SL, Vogel JW, Marks SM, Crowley S, O’Neil JP and Jagust WJ: Neural compensation in older people with brain amyloid- β deposition. Nature Neuroscience 17(10):1316-1318 (2014).
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http://www.ncbi.nlm.nih.gov/pubmed/25217827