Periodic Reporting for period 3 - BrainDyn (Tracking information flow in the brain: A unified and general framework for dynamic communication in brain networks) Reporting period: 2020-02-01 to 2021-07-31 Summary of the context and overall objectives of the project The brain is constituted of a set of specialized neural networks that must communicate with each other so that cognition emerges. This project tests a theory concerning the flexible communication between brain areas based on neuronal rhythms.It postulates that slow internal oscillations (<20 Hz) establish or prevent communication between brain areas whereas gamma oscillations (> 30 Hz) represent local neural processing of sensory information. To test the model, a variety of methods will be used.The theoretical approach and methodological developments used in this research will serve as a basis for future basic and clinical research directly relevant to society. Indeed, several brain related troubles (e.g. chronic pain or schizophrenia) have been associated with altered brain communication. The overall objectives are to better understand brain communication and to develop brain stimulation therapies based on the results obtained in this project. Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far Since beginning the project, we have run an experiment using functional magnetic resonance imaging (fMRI) and EEG combined with 52 subjects. We found so far that fast (i.e. gamma) and slow (here in the alpha band, around 10Hz) oscillations are associated with specific layers of the cortex (which contains around 6 layers) and are involved in specific processing of the stimuli, as predicted by the framework, presented to the participants.We have also analysed data obtained in Monkey revealing similar results as well as the interaction between the oscillations at different frequency in the different layers of the cortex.We have recently obtained the ethical approval for running the remaining fMRI and Magnetoencephalography (MEG) experiments aimed at determining whether the slow oscillations control the flow of information in the visual network. The scripts for running the analyses have already been developed during the time necessary for obtaining this approval.An opinion paper about the role of oscillations in local and global computational processing of visual information, recently enriched by a collaboration, has been written and is about to be submitted. Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far) Alpha oscillations are widely considered to have low spatial specificity in the brain in our community. The hypotheses regarding the cognitive processes that these oscillations can be associated with are partially based on that idea. The feature specificity (very high spatial specificity) of alpha oscillations in superficial layers is therefore a ground-breaking result and was only predicted by our framework. Likewise, the differential relationship between slow oscillations in superficial and deep layers and fast oscillations was predicted by the framework and has never been shown before.We now expect to show, using MEG, that superficial slow oscillations are associated with setting up the specific communication between layers (associated with fast oscillations) controlling the flow of information, while deep alpha oscillations would be associated with broader cognitive processes such as inhibition of areas or visual integration. ercpicture.png
