Ethnic disparities in the longer-term clinical care and outcomes of stroke patients in England.

Alzheimer's disease (AD) is characterized by progressive memory loss, typically linked to hippocampal dysfunction during episodic memory processes, and often preceded by neuropsychiatric symptoms and emotional dysregulation. Similarly affected early on in AD is the locus coeruleus (LC), the primary source of cortical norepinephrine neuromodulation. Its proximity to the fourth ventricle and exposure to small capillaries likely make the LC vulnerable to toxins and accumulation of tau pathology., , Based on animal and human studies, tau pathology in the LC spreads progressively to the entorhinal cortex and neocortical regions via axons. This topographical progression of tau is a central mechanism in AD, influencing multiple cognitive domains., , , LC neuronal loss in AD ranges from 30% to 80%, with reduced structural integrity evident even in MCI., , This noradrenergic system deterioration is well established and highly implicated in cognitive decline., ,