Bridging Brain Structure and Function by Correlating Structural Connectivity, Cortico-Cortical Transmission and Direct Electro-Stimulation

Study Overview
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Brief Summary
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Elucidating the structure-function relationship of the brain is one of the main open questions in neuroscience. The capabilities of diffusion MRI-based (dMRI) techniques to quantify the connectivity strength between brain areas, namely structural connectivity (SC), in combination with modalities such as electroencephalography (EEG) to quantify brain function have enabled advances in this field. However, so far the actual relationship between SC measures and measures of information transport between neuronal patches has not been determined. In this project, we aim to establish a relationship between dMRI SC measures, direct measures of electrical properties of the human brain cortex obtained with electrocorticography (ECoG), and response elicited by direct electrostimulation of the brain (DES). Ten patients operated on awake surgery for brain tumor removal will be included. First, a dMRI will be acquired prior to the surgery, in order to extract SC indices through probabilistic tractography. Then, intrasurgical cortico-cortical electrical measures will be obtained by ECoG electrodes positioned on the predefined cortical terminations of the designated bundles. These measures will be correlated to functional responses obtained during the cortical cartography, following the common DES procedure. The results of this multi-modal approach combining structure and function explorations of the brain should help to elucidate the relationship between non-invasive (dMRI) SC measures and cortico-cortical transmission properties (delays, transfer functions), and should boost the understanding of cognitive function as well as neurosurgical planning for the treatment of pathologies such as brain tumor resection and drug-resistant epilepsy.

Official Title
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Anatomo-functional Study of the Brain Cortical and Sub-cortical Connectivity Using Diffusion MRI, Electrocorticography and Direct Electrical Stimulation

Conditions
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Tumor, Brain

Intervention / Treatment
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* Other: electrocorticography with electrostimulation
* Other: dRMI


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patient eligible at an awake surgery for a brain tumor resection Informed consent of the patient Exclusion Criteria: Contraindication to MRI Withdrawal of the patient's consent

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: dMRI and electrocorticography<br>Direct measurements of cortical electrical properties of patients operated on awake surgery for a brain tumor, using electrocorticography (ECoG), based on the dMRI tractography data previously acquired for each patient. | Other: electrocorticography with electrostimulation<br>* The investigators aim to establish a relationship between dMRI SC measures, direct measures of electrical properties of the human brain cortex obtained with electrocorticography (ECoG), and response elicited by direct electrostimulation of the brain (DES)<br>Other: dRMI<br>* The investigators aim to establish a relationship between dMRI SC measures, direct measures of electrical properties of the human brain cortex obtained with electrocorticography (ECoG), and response elicited by direct electrostimulation of the brain (DES)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Descriptive activity of brain with dMRI results |  | after the operation (1 month) | 
| Descriptive functional responses elicited by the direct electrostimulation of the cortex. |  | after the operation (1 month) |