A compositional semantics for Venn diagrams.

Late-life depression (LLD) refers to major depressive disorder occurring in older adulthood and represents a prevalent and clinically significant condition associated with increased disability, medical comorbidity, and mortality (; ; ; ). LLD is a heterogeneous neuropsychiatric disorder () characterized by a broad constellation of affective, cognitive, autonomic, and somatic disturbances (; ). In LLD, these depressive symptoms often coexist with executive dysfunction (), emotional dysregulation (), attention deficits (), and prominent physical complaints (), making the clinical presentation highly variable and often difficult to disentangle using symptom-based assessments alone (). This heterogeneity has motivated growing interest in identifying objective, neurobiologically grounded markers () that can capture dysfunction in specific brain networks implicated in LLD, rather than treating the disorder as a unitary clinical entity (). One neural system that has received increasing attention in LLD is the locus coeruleus–norepinephrine (LC–NE) network (; ). The LC–NE system plays a central role in regulating arousal and cognitive control, and its structural and functional integrity is known to change with ageing (; ; ; ). Dysregulation of LC–NE signaling has been implicated in depression-related alterations (; ; ; ; ), and research, primarily from imaging studies, has demonstrated disruptions in the LC-centered system in LLD compared to healthy controls (; ; ). While neuroimaging approaches provide valuable insight into these impairments, their cost and methodological complexity limit their widespread use for probing LC–NE function in large or diverse samples. These limitations underscore the need for accessible and theory-driven behavioral paradigms that can probe LC–NE–related executive and emotional control processes in older adults. From a functional perspective, LC–NE system dysregulation in LLD is particularly evident in processes requiring the prioritization of emotionally salient information under conditions of competition (). Because the LC–NE system contributes to neural gain and the prioritization of behaviorally relevant information (), emotional conflict control and valence processing provide behavioral contexts in which LC–NE-related influences may be engaged. The emotional face–word Stroop task (, ) is a well-validated paradigm for examining the resolution of competition between target facial expressions and incongruent emotional distractors. Neuroimaging and pupillometric studies have implicated LC–NE-related processes in emotional interference resolution and associated prefrontal and cingulate activity (, , ). These findings position the task as a useful framework for examining emotional control processes that may be influenced by LC–NE signaling. However, while it is established that congruency and valence modulate global behavioral and autonomic responses (; ), how emotional congruency and valence influence fine-grained oculomotor behavior remains largely unexplored in LLD.