DESCRIPTION (provided by applicant): Human civilizations are hallmarked by communicating magnitude, time, and space in the form of numeral symbols. Humans learn to speak a certain language and read its symbols depending on the culture they live in. All brains are known to have specialized group of neuronal populations in the visual system that, through education and culture, are pruned to recognize these visual symbols, and be able to feed them to specific networks of the brain where they are processed. The existence of neuronal populations in the brain's visual system to respond selectively to numerals is a fascinating example of how nurture affects our nature, i.e., how cultural experience and education change the brain's biological function. Yet, relatively little is known about the way these specialized populations of neurons operate in the visual system and with the networks of language and numerosity. The proposed work will be the first multimodal approach to combine direct recordings from the surface of the human brain (electrocorticography, ECoG) as well as causing reversible functional perturbations by electrical brain stimulation (EBS). The proposed work aims to provide a comprehensive map of the location and functional properties and connectivity of the specialized areas of the ventral temporal cortex (VTC) for numerals (i.e., visual numeral area (VNA). Lastly, we propose to study how the neuronal population activities change in the VTC when human subjects learn to associate foreign symbols with their categorical and semantic identities. We are hopeful and confident that our novel multimodal approach will provide unprecedented spatiotemporal information to clarify the outstanding questions about the functional contributions of VTC subregions to how numbers are processed in the human brain.