Precision functional mapping of the language and executive networks: implications for aging, stroke recovery, and targeted neuromodulation

Abstract: Association cortex is organized into multiple juxtaposed large-scale distributed networks that support higher-order cognition in humans, including language and cognitive control. A prominent view holds that these networks become less segregated, or reorganize, in healthy aging and after brain injury. In this talk, I will argue that this apparent reorganization may instead partly reflect the loss of each individual's idiosyncratic network topography when adjacent networks measured with fMRI are averaged across individuals. To test this, I use task-based functional localizers to identify the language and domain-general executive networks within individuals. I will first show that these two networks remain functionally dissociable both across the adult lifespan and after focal injury. In aging, the executive network declines while the language network is preserved, mirroring the cognitive functions they support; after stroke, better language outcomes depend on the residual language network rather than on reorganization across language and executive networks. Probing the executive system more finely through precision network mapping of densely sampled individuals, I will then show that even adjacent prefrontal regions within the executive territory belong to distinct networks that couple to separate regions of the striatum and support distinct functions. I will conclude by demonstrating 1) why mapping these higher-order association networks precisely within individuals matters for brain-stimulation treatments such as transcranial magnetic stimulation, and 2) how precision targeting within individuals can be used to optimize the modulation of these specific networks, advancing both our understanding of their function and the treatment of neurological and psychiatric disorders.