Precuneus amyloid burden is associated with reduced cholinergic activity in Alzheimer disease

Objective: This study examined the relationship between postmortem precuneus cholinergic enzyme activity, Pittsburgh compound B (PiB) binding, and soluble amyloid-β concentration in mild cognitive impairment (MCI) and Alzheimer disease (AD). Methods: Choline acetyltransferase (ChAT) activity, [3H]PiB binding, and soluble amyloid-β1-42 (Aβ42) concentration were quantified in precuneus tissue samples harvested postmortem from subjects with no cognitive impairment (NCI), MCI, and mild AD and correlated with their last antemortem Mini-Mental State Examination (MMSE) score and postmortem pathologic evaluation according to the National Institute on Aging-Reagan criteria, recommendations of the Consortium to Establish a Registry for Alzheimer\u27s Disease, and Braak stage. Results: Precuneus ChAT activity was lower in AD than in NCI and was comparable between MCI and NCI. Precuneus [3H]PiB binding and soluble Aβ42 levels were elevated in MCI and significantly higher in AD than in NCI. Across all case subjects, reduced ChAT activity was associated with increased [3H]PiB binding, increased soluble Aβ42, lower MMSE score, presence of the APOE®4 allele, and more advanced AD pathology. Conclusions: Despite accumulating amyloid burden, cholinergic enzyme activity is stable in the precuneus during prodromal AD. A decline in precuneus ChAT activity occurs only in clinical AD, when PiB binding and soluble Aβ42 levels are substantially elevated compared with those in MCI. Anti-amyloid interventions in MCI case subjects with a positive PiB PET scan may aid in reducing cholinergic deficits and cognitive decline later in the disease process. Copyright © 2011 by AAN Enterprises, Inc

Can Positive Employees Help Positive Organizational Change? Impact of Psychological Capital and Emotions on Relevant Attitudes and Behaviors

Although much attention has been devoted to understanding employee resistance to change, relatively little research examines the impact that positive employees can have on organizational change. To help fill this need, the authors investigate whether a process of employees’ positivity will have an impact on relevant attitudes and behaviors. Specifically, this study surveyed 132 employees from a broad cross-section of organizations and jobs and found: (a) Their psychological capital (a core factor consisting of hope, efficacy, optimism, and resilience) was related to their positive emotions that in turn were related to their attitudes (engagement and cynicism) and behaviors (organizational citizenship and deviance) relevant to organizational change; (b) mindfulness (i.e., heightened awareness) interacted with psychological capital in predicting positive emotions; and (c) positive emotions generally mediated the relationship between psychological capital and the attitudes and behaviors. The implications these findings have for positive organizational change conclude the article