The ability to recognize and use objects according to their function (e.g., fork, hammer, pencil) requires coordinated processing across multiple brain regions in temporal, occipital and parietal cortex. Regions in the left parietal lobule are known t support critical aspects of object-directed action, such as grasping and object manipulation. It is known that stroke lesions affecting the left parietal lobule can cause impairments to the ability t manipulate objects correctly according to their function. However, it is not known whether cortical lesions introduced in parietal areas during neurosurgical procedures to remove brain tumors lead to the same types of action impairments. The central clinical goal of this research activity is to carry out the foundational study to determine whether or not corticectomy of parieta cortex to remove brain tumors causes neuropsychological impairments for action knowledge, and whether presurgical functional magnetic resonance imaging (fMRI) provides useful information for mitigating such impairments. The research activity also uses a combination of fMRI and behavioral measures in neurosurgery patients, collected before and after their surgery, to draw causal inferences about how action knowledge is organized and processed in the human brain. The central scientific goal of this research activity is to test a neurocognitive model about how action information is represented in parietal cortex and how it is accessed from visual input. Specific hypotheses are tested about how action representations in the parietal lobule interact in online processing (Aim#1), how visual processing of an object is communicated to parietal action representations (Aim#2), and how action information is stored in parietal cortex (Aim#3). This research program serves two broad goals. First, it will generate a new type of feedback about patient outcome to neurosurgeons that will inform future surgical planning for resection of brain tumors. Importantly, we not only determine whether action impairments are associated with parietal corticectomy, but also test the efficacy of a specific presurgical fMRI protocol for guiding the surgical resection and mitigating the likelihood of disabling action impairments after surgery. Second, hypotheses about the neural organization of object-directed action knowledge are tested, and causal inferences are drawn about the brain processes that support our ability to recognize and manipulate objects according to their function. The results of these investigations have implications for understanding how parietal action systems recover from cortical damage generally (e.g., stroke, TBI). In addition, studying the restricted domain of object- directed action, which has well-established neural substrates, will advance our general understanding of how a brain lesion alters functioning within a broader network, and how network function relates to behavior.