The role of the ventral visual pathway processes in activities of daily living - SUMMARY Everyday object-directed actions—picking up a cup, grasping a handle, using a fork—are fundamental to daily living. Brain lesions that disrupt the perceptual, cognitive, and motor processes underlying such actions can dramatically reduce quality of life. A central challenge for cognitive neuroscience and clinical neuropsychology is to specify how perceptual and conceptual representations of objects, computed in occipito-temporal regions, are integrated with dorsal visual pathway and frontal-parietal systems that calibrate hand, eye, and body actions in real time. A hallmark of this integration is end-state-comfort, in which an initial grasp anticipates how an object will be manipulated, reflecting conceptual features such as object function, visual form, surface texture, material properties, and internal weight distribution. This program uses state-of-the-art lesion-function mapping to generate causal evidence about the roles of occipito-temporal, occipito-parietal, and subcortical regions in supporting object-directed action. It addresses three Aims: (Aim 1) to identify cortical and white-matter pathways necessary for perceptual and conceptual processing of object properties, (Aim 2) to determine how these regions support grasp-to-use actions and end- state-comfort planning, and (Aim 3) to evaluate how lesion variability in posterior cerebral artery (PCA) stroke patients relates to independence in instrumental activities of daily living within a biopsychosocial model of neurocognition, quality of life, and social-emotional well-being. Significance. This work addresses a fundamental problem in cognitive neuroscience with direct translational impact: understanding how brain lesions alter not only local computations but also the function of anatomically distal yet interconnected regions. By linking lesion distribution and residual function to patients' ability to perform instrumental activities of daily living, the project will provide foundational insights into the neurobiological basis of real-world functional outcomes after PCA stroke. Innovation. The program is innovative in three ways: (a) it shifts the focus from dorsal pathway mechanisms of action control to the underexplored role of occipito-temporal regions and pathways in supporting functional object use, (b) it leverages the understudied subpopulation of PCA stroke patients to test hypotheses about object-directed action, and (c) it employs cutting-edge lesion-function mapping techniques that integrate behavioral paradigms, diffusion MRI, fMRI, and patient-reported quality-of-life measures. Impact. By integrating lesion mapping with behavioral and neuroimaging measures of action and with biopsychosocial models of patient function, this research advances a network-based account of object-directed action. The findings will inform theories of brain organization and establish new methodological standards for linking brain lesions to real-world outcomes.
