platforms & TECHNOLOGIES

INS is a well equipped, state-of-the-art research facility strategically embedded within France’s largest hospital

HIGH PERFORMANCE CLUSTER

The Virtual Brain (TVB) is an open source neuroinformatics platform, which combines a large-scale brain network model and neuroimaging modality (s/EEG/MEG & fMRI) simulator, optimized for realistic brain connectivity & geometry and neural mass models, with a framework for constructing, visualizing and analyzing brain network models in a collaborative, project oriented user interface, accessible via web browser.  General purpose use is supported via SSH or Jupyter, in addition to support for software development with an onsite GitLab instance. This platform is backed by dedicated high-performance computing (HPC) hardware, complemented by clustered nodes for virtual machines running public-facing web services, located in the medical faculty of the La Timone campus. Installed in September 2011, the cluster dedicates 95 TB high-performance storage, 2.5TB RAM, 400 Xeon cores & 8 NVidia GPUs to both local users in modeling collaborations and worldwide users of the TVB platform.

Users of the TVB platform can find additional information on the TVB cluster wiki or contacting a member of the staff: Huifang Wang (IR) or Marmaduke Woodman (IR)

MEG

Magnetoencephalography (MEG) is the recording of the brain’s magnetic activity. This activity is the counterparts of the electrical activity that originate from the brain, recorded by EEG. These techniques are the only ones that are directly related to the neural activity and have enough time resolution to track brain activity. One of the great advantages of the MEG over EEG is the very small effect of the geometry of the different media of the head, especially the skull, on the recorded signals.

Our MEG laboratory uses a 248 magnetometers MEG system (4D Neuroimaging magnes 3600), installed within the Neurophysiology department of La Timone hospital (Head: F Bartolomei). The system was co-financed by: Conseil Régional PACA, Conseil Général 13, Conseil Général 06, Marseille Provence Métropole, INSERM, CNRS, INRIA. The lab is equipped with stimulation apparatus, including video projection and Stax calibrated system for auditory stimulation. It belongs to the Aix-Marseille Université and is accessible to all teams involved in fundamental and clinical brain research. The MEG is collaborating in particular with the Epilepsy clinical group of AP-HM and with the Institute for Language Communication and the Brain.

The research team of the MEG lab is specialized in confronting results of source localization to intracerebral EEG and in designing and optimizing signal processing methods for multimodal functional investigation of human cerebral activity (pathological and physiological) (see Dynamap publications). For all publications of the MEG lab, see MEG publications.

MEG Lab team: Jean-Michel Badier (technical director); Christian Bénar (scientific director); Bruno Colombet (software developer).

The MEG laboratory has developed a software called Anywave for the visualisation and analysis of electrophysiological data: MEG, EEG, SEEG (developer: Bruno Colombet), available there. The guiding principles are modularity and cross-platform portability.

TMS | EEG-TMS

Transcranial magnetic stimulation (TMS) is a powerful tool that can directly, both temporarily and focally, perturb brain dynamics in healthy human subjects engaged in different tasks. In the last decades, this technique has become much more powerful due to its combination with individual MRI, allowing to precisely guide TMS according to individual anatomy. Recently, the combined use of stereotactic TMS with EEG further expanded the scope of TMS towards focal studies of living human brain’s reactivity and connectivity. From this reaction to TMS, many things can be discovered concerning the dynamical state of a brain, and abnormalities in brain reactivity and connectivity can be identified. Finally, more recently, we triggered TMS according to the dynamic state of the brain via online continuous processing the alpha cortical rhythm.

At INS, we have two Magstim® 200 TMS stimulators (Magstim, Whitland, UK), potentially coupled with a bi-stim module, coplanar figure-of-eight coil (external loop diameter of 9 cm), sham coil and double cone coil. The stimulator generates a monophasic magnetic field of up to 1.7 Tesla. The coil is maintained in the desired position by a custom apparatus and can be moved or placed optimally, while keeping its position stable throughout the experiment. The stimulation system is connected to a neuro-navigation device (Navigation Brain System 2.3, Nexstim, Helsinki, Finland) and uses an individual’s anatomical T1 MRI to precisely guide the stimulation. The system computes an estimate of the electrical field induced in the cortex by the TMS pulse in real time and displays it on the subject’s MRI. The characteristics of the electric field induced by each TMS pulse (localization, orientation and intensity) are recorded by the neuro-navigation device. In addition, we have a TMS-compatible EEG system comprising of BrainAMP Direct-Current amplifiers (BrainProducts, Gilching, Germany) and a 62-electrode cap (Fast & Easy Cap). Data is recorded using BrainVision Recorder software EEG online processing. It is also possible to trigger TMS (or any other stimulus) depending on some properties of the EEG signal using this Brain Vision Recview software.

For more information about the TMS lab, please contact Mireille Bonnard.