"Single-pulse direct electrical stimulation of cortical regions in patients suffering from focal drug-resistant epilepsy who are explored using intracranial electrodes induces electrophysiological responses. Such cortico-cortical induced potentials can be used to infer functional and anatomical brain connectivity.We will develop methods to analyse those responses using neuroimaging tools in order to create a new probabilistic atlas of functional tractography of the human brain, which will be made freely available to the clinical and neuroscience community. Several thousands of stimulation runs performed in several hundreds of patients will be included in the atlas database to reach a nearly full coverage of the human cortex (inclusion of 540 patients retrospectively and of 172 patients/year prospectively, from 8 French and 1 Czech epilepsy surgery centres). As a proof of concept, we generated for F-TRACT scientific document a preliminary database of 1535 stimulation runs performed in 35 adult patients. To illustrate the potential of our approach, in particular to refine neurobiological models of cognitive systems, we use here this preliminary atlas to demonstrate the asymmetry of the functional connectivity between Wernicke’s area and Broca’s area, two key nodes of the language network.This new atlas of functional tractography will be very useful to understand how the brain works and to develop neurocomputational models at a large scale. It will also allow the development of new clinical tools for the presurgical evaluation of intractable epilepsy. It is very complementary to other structural and functional approaches, such as MRI diffusion and functional mapping derived from metabolic, optical and electromagnetic techniques. The open access to this unique atlas of functional tractography will allow to explore in the future its numerous properties in relation to distributed brain networks in the domains of neuroanatomy, neurocognition and neurophysiopathology."