Background and Objectives:The predictable Braak staging scheme suggests that cortical tau progression may be related to synaptically connected neurons. Animal and human neuroimaging studies demonstrated that changes in neuronal activity contribute to tau spreading. Whether similar mechanisms explain tau progression from the locus coeruleus (LC), a tiny noradrenergic brainstem nucleus involved in novelty, learning, and memory and among the earliest regions to accumulate tau, has not yet been established. We aimed to investigate whether novelty-related LC activity was associated with the accumulation of cortical tau and its implications for cognitive decline.Methods:We combined functional MRI data of a novel versus repeated face-name learning paradigm, [18F]-FTP-PET, [11C]-PiB-PET, and longitudinal cognitive data from 92 well-characterized older individuals in the Harvard Aging Brain Study. We related novelty versus repetition LC activity to cortical tau deposition, and to longitudinal decline in memory, executive function, and the Preclinical Alzheimer’s Disease Cognitive Composite (version 5; PACC5). Structural equation modeling was used to examine whether entorhinal cortical (EC) tau mediated the relationship between LC activity and cognitive decline and whether this depended on beta-amyloid deposition.Results:The participants’ average age at baseline was 69.67 ± 10.14 years. 51 participants were female. 91 participants were cognitively normal (CDR global=0), and one had MCI (CDR global=0.5) at baseline. Lower novelty-related LC activity was specifically related to greater tau deposition in the medial-lateral temporal cortex and steeper memory decline. LC activity during novelty versus repetition was not related to executive dysfunction or decline on the PACC5. The relationship between LC activity and memory decline was partially mediated by EC tau, particularly in individuals with elevated beta-amyloid deposition.Discussion:Our results suggested that lower novelty-related LC activity is associated with the emergence of EC tau and that the downstream effects of this LC-EC pathway on memory decline also require the presence of elevated beta-amyloid. Longitudinal studies are required to investigate whether optimal LC activity has the potential to delay tau spread and memory decline, which may have implications for designing targeted interventions promoting resilience.

Academics and practitioners emphasize the rising importance of Chief Human Resource Officers (CHROs). CHROs act as heads of staff—they motivate the personnel and offer guidance. This study helps clarify the impact of increasingly relevant CHROs and reveals how their company and role tenure influence firms’ social performance. Drawing on a multisource longitudinal dataset of S&P 500 firms, we empirically validate our hypotheses. The sample contains 283 companies with 1944 firm-year observations from 2005 to 2017 and combines manually collected top management team data with data from Thomson Reuters Datastream. Our results show that there is a negative relation between CHROs with long company tenure and firms’ social performance, whereas CHROs with long role tenure positively relate to firms’ social performance. We also investigate the moderating role of CEO prior experience (i.e., HR experience, education, company and role experience) on the effect of CHRO company and role tenure on firms’ social performance. Surprisingly, CEO prior experience negatively moderates the relationship between CHRO role tenure and firms’ social performance. Overall, this article offers novel implications for the CHRO role and uncovers a distinction between two types of CHROs: CHRO firm dinosaurs versus CHRO role gorillas.