Language and speech are among the most impressive functions of the human brain. While the regions in the frontal, temporal, and parietal lobes that constitute the cortical language network have already been identified, the principles of organization and orchestration of neural information processing in the human brain’s language and speech network remain largely unknown.

In this project, we will investigate the mechanisms of human vocal communication in a key area of ​​the language and speech network, Broca’s area (BA 44) in the left inferior frontal gyrus (LIFG), at different neuronal levels of detail. To this end, we will perform intraoperative neural measurements directly from Broca’s area in neurosurgical patients undergoing awake surgery for the removal of tumors in the left cerebral hemisphere. We combine electrocorticography (ECoG), intracortical microelectrode recordings, and ultra-high-channel measurements of single-cell neuronal activity across cortical layers to investigate both the population dynamics and local network activity of individual neurons that collectively enable humans to verbally express thoughts, intentions, and emotions. At the macroscopic level, we will examine the modular organization and neuronal dynamics in the language-selective and general-cognitive subregions of the LIFG that govern the planning, production, and composition of human speech sounds. At the mesoscopic level, we will explore how the activity of neuronal populations in circumscribed cortical areas of Broca’s area is orchestrated for the preparation and production of speech. At the microscopic level, we will determine how elementary speech sounds and phonetic constructs are encoded by individual neurons and how neuronal population patterns contribute to temporal integration and combinatorics during speech production.