fMRI User Guide
Electrophyisology Recording in Functional MRI (fMRI)
Environments using TDT
This document is a hardware and software instructional reference for conducting
electrophysiology recordings in Functional MRI (fMRI) environments using TDT hardware and
software.
The challenge of using both modalities simultaneously is that the electrophysiology recording
system can introduce imaging artifacts, and the MRI system introduces artifacts on the
electrophysiology system. The purpose of this guide is to discuss proper hardware/software
setup to minimize these artifacts.
This guide will not go into any meaningful details about electrode placement or implantation
surgery, and assumes you can record clean signals outside of the fMRI environment.
Motivation
Electrophysiology and fMRI are two very different types of recording modalities. The
fi
rst is
recording electrical activity from the brain of a subject. The data is
fi
ltered for both fast neural/
spiking activity and longer term activity of local
fi
eld potentials (LFP). The subject can be head-
fi
xed or freely moving.
In fMRI the subject is head-
fi
xed and restrained in a tube. It measures changes in blood
fl
ow
and relies on the fact that blood
fl
ow and neuronal activity are coupled. The activity is on a
longer time scale, from several seconds to minutes. This looks at the whole brain as opposed
to a very small section of the brain.
Combining the two recording methodologies provides a better understanding of the underlying
architecture of the brain. You can use the electrophysiology to validate the fMRI data by
determining a correlation between fMRI signals and LFP or spiking data. You can also record
both neural activity and fMRI activity from multiple sites to see time course of signals in the
brain.
You can use the electrophysiology data to validate the blood-oxygen-level dependent (BOLD)
signal in fMRI. Integrating the two helps you understand the relationship between BOLD and
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