MRIES: A Matlab Toolbox for Mapping the Responses to Intracranial Electrical Stimulation.

Kaijia Sun,Wenjing Zhou,Yunxian Bai,Liang Wang,Haixiang Wang

doi:10.3389/fnins.2021.652841

Abstract

ProposeDirected cortical responses to intracranial electrical stimulation are a good standard for mapping inter-regional direct connectivity. Cortico-cortical evoked potential (CCEP), elicited by single pulse electrical stimulation (SPES), has been widely used to map the normal and abnormal brain effective network. However, automated processing of CCEP datasets and visualization of connectivity results remain challenging for researchers and clinicians. In this study, we develop a Matlab toolbox named MRIES (Mapping the Responses to Intracranial Electrical Stimulation) to automatically process CCEP data and visualize the connectivity results.MethodThe MRIES integrates the processing pipeline of the CCEP datasets and various methods for connectivity calculation based on low- and high-frequency signals with stimulation artifacts removed. The connectivity matrices are saved in different folders for visualization. Different visualization patterns (connectivity matrix, circle map, surface map, and volume map) are also integrated to the graphical user interface (GUI), which makes it easy to intuitively display and compare different connectivity measurements. Furthermore, one sample CCEP data set collected from eight epilepsy patients is used to validate the MRIES toolbox.ResultWe show the GUI and visualization functions of MRIES using one example CCEP data that has been described in a complete tutorial. We applied this toolbox to the sample CCEP data set to investigate the direct connectivity between the medial temporal lobe and the insular cortex. We find bidirectional connectivity between MTL and insular that are consistent with the findings of previous studies.ConclusionMRIES has a friendly GUI and integrates the full processing pipeline of CCEP data and various visualization methods. The MRIES toolbox, tutorial, and example data can be freely downloaded. As an open-source package, MRIES is expected to improve the reproducibility of CCEP findings and facilitate clinical translation.

Highlights

Mapping human brain connectivity quantitatively on a large scale has attracted increasing attention in recent years
In comparison with statisticalbased approaches (e.g., Granger causality) for measuring direct connectivity from the EEG or functional magnetic resonance imaging (fMRI) signals (Reid et al, 2019; Jafarian et al, 2020), detecting cortical responses to invasive electrical stimulation is a good standard for mapping interregional direct connectivity, and has been widely used in physiological (Enatsu et al, 2015, 2016; Keller et al, 2018; Usami et al, 2018; Dionisio et al, 2019) and pathological studies (David et al, 2011; van ’t Klooster et al, 2011, 2017; Boido et al, 2014; Bartolomei et al, 2017; Tousseyn et al, 2017; Zhao et al, 2019)
We develop a Matlab toolbox named MRIES (Mapping the Responses to Intracranial Electrical Stimulation) to integrate the full pipeline of corticocortical evoked potential (CCEP) data processing and connectivity visualization methods

Summary

Introduction

Mapping human brain connectivity quantitatively on a large scale has attracted increasing attention in recent years. Numerous studies have revealed important physiological (Watrous et al, 2013; Solomon et al, 2017, 2019) and psychological evidence (van Diessen et al, 2013; Bartolomei et al, 2017; Lagarde et al, 2018) from the perspective of brain connectivity. There are many methods of probing brain connectivity, such as diffusion tensor imaging (DTI), which is used to measure anatomical connectivity, and functional magnetic resonance imaging (fMRI), a way of measuring functional connectivity. Such neuroimaging techniques cannot quantitatively measure the information that is transferred directly between the areas. In comparison with statisticalbased approaches (e.g., Granger causality) for measuring direct connectivity from the EEG or fMRI signals (Reid et al, 2019; Jafarian et al, 2020), detecting cortical responses to invasive electrical stimulation is a good standard for mapping interregional direct connectivity, and has been widely used in physiological (Enatsu et al, 2015, 2016; Keller et al, 2018; Usami et al, 2018; Dionisio et al, 2019) and pathological studies (David et al, 2011; van ’t Klooster et al, 2011, 2017; Boido et al, 2014; Bartolomei et al, 2017; Tousseyn et al, 2017; Zhao et al, 2019)

Methods

Results

Conclusion