Attentional resilience in older adults - in delirium and alzheimer's disease (ad), which increase the risk for each other, patients suffer deficits in executive functions, including attentional control

There is a critical GAP in our understanding of the mecha- nisms by which attentional control capacity may promote cognitive resilience in both delirium and dementia. Even under normal conditions neural resources for navigating the world around US are fundamentally limited (IE, we can't attend to everything in our environment), yet attentional control allows the brain to effectively allocate neural resources to accomplish cognitive tasks. During stressors that limit neural resources further, EG neuro- inflammation after surgery or ad-related neurodegeneration, attentional control can compensate for neuronal injury to preserve cognitive function by marshaling remaining neural resources. Given the potential protective benefits of robust attentional control, this proposal introduces attentional resilience-IE the ability to retain robust attentional control despite physiological stressors-and evaluates its potential underlying neural mecha- nisms using the stressor of scheduled surgery in cognitively healthy older adults as a "natural experiment." our overall objective is to better understand the neural mechanisms underlying attentional resilience, which enable individuals to more effectively allocate neural resources to remain attentive to their surrounding environ- ment despite neuronal injury and/or neuro-inflammation. Our central hypothesis is that neural mechanisms underlying robust attentional control before surgery facilitate attentional resilience after surgery. Our aims eval- uate neural activity patterns that have been linked to robust attentional control. Given the well-established link between electroencephalogram (EEG) alpha (7-13 HZ) power and attentional control, aim 1 focuses on the ability of attentional control processes to enable attentiveness by attenuating alpha power. In aim 2, we explore alpha- driven enhancement of sensory processing, an attentional control mechanism that amplifies neural responses to relevant sensory stimuli. These attentional control processes facilitate externally directed attention, and we will evaluate how their mechanisms relate to attentional resilience. Building on this, aim 3 explores neural circuit contributors to these attentional control processes as possible mechanisms underlying attentional resilience. Because robust neural circuits depend on healthy neuronal substrates largely free from ad-related pathology, we will evaluate the effect of TAU pathology on attentional resilience mediated by coordination of the dorsal at- tention network and the default mode network, two complementary neural circuits critical for attentional control. In SUM, this project will advance understanding of why some older adults maintain strong attentional perfor- mance after surgery while others do not. In particular, this work will reveal key neural-systems-level mechanisms that support attentional control capacity and link low-level neuronal damage to diminished high-level cognitive performance. Finally, this work supports the long-term goal of identifying potentially modifiable neural targets for delirium and dementia interventions.