Building Experimental Paradigms for EEG

Research Team

Colleen Healy

Dr. Elizabeth Lydon

Introduction

NACE Career Readiness Competencies

Research Team

Colleen Healy

Psychology/Pre-Med Major

Dr. Elizabeth Lydon

Speech Pathology and Audiology

Introduction

This project focuses on the learning process of engaging with the set up and design of a research lab in EEG. Content includes what steps must be taken in order to prepare for an EEG study, learning about the EEG system itself, and the process of cleaning and collecting data with an EEG system.

EEG

An EEG, or electroencephalogram, is a non-invasive way to measure the electrical activity of the brain from the surface
The electrodes of an EEG detect small shifts in the electrical activity of neurons and record these brain waves in Hertz on a graph for analysis
EEGs can be used to collect Event Related Potentials (ERPs), mapping the exact timing of neuronal activity during cognitive tasks in a research setting
ERSPs (event-related spectral perturbations) can be used to go beyond what a typical ERP can capture by measuring aspects of activity such as amplitude and phase of brain response
Resting State EEG is used to measure the brains spontaneous activity and specifically helps in tracking executive function performance

Our System

The EEG electrodes used in this lab are g.tec's g.SAHARA hybrid active electrodes. This system allows for active amplification and buffering of electrical signals on-site at the scalp as opposed to passive transmissions. The hybrid aspect of these electrodes offers the unique ability to perform both dry and wet recordings with the same electrodes. The system is able to capture the whole EEG frequency spectrum from 1-40 Hz and is currently the only dry system that works for all frontal, central, occipital, temporal and parietal sites.

This image depicts the g.SAHARA hybrid active electrode

Data Cleaning

EEG data acquisition and cleaning is a complex, multistep process. In order to obtain the best data in collection, it is necessary to understand the process of cleaning data to best grasp what makes data “good”.

Data collection for our EEG lab is done using Independent Component Analysis (ICA)
Individual artifacts are identified in EEG trials after collection in order to reject trials that include muscle activity, line noise or eye movement

Set Up

After learning about data cleaning there were adjustments that could be made to our lab set up and questions that could be answered to best establish an environment that would be most conducive of clean data collection.

Question such as:

Can take place in a carpeted room or will the static create too much noise for collecting data?
How much movement can the EEG system tolerate without disturbing neural data collection?
Will the participants we are working with tolerate experimental conditions that would increase signal conduction such as using conducting gel?

Future Directions

The next steps in the research process for the lab are to generate an experimental paradigm and collect data on participants
Establishing a paradigm with a background understanding of data cleaning allows for the optimal attention to preventing the need to discard data post-collection
Data acquisition and analysis will be a smoother process due to the prior attention to what kinds of data will ultimately be discarded

Acknowledgements

Thank you to my mentor, Dr. Elizabeth Lydon, for her guidance.

NACE Career Readiness Competencies

Joining the lab at the very beginning has allowed me to learn more about, not only EEG research, but also what it takes to establish and run a research lab start to finish
My increased knowledge of the research process, cognitive testing, and examining data will serve me well as I enter the medical field post-graduation
This project specifically relates to my intrests as a psychology major focused on cognitive processes and allows me to pursue education outside of a classroom setting.

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