The NeuroCognitive Imaging lab is equipped with two EEG/ERP recording systems.
One is a 128 channel Electrical Geodesics GES-250 system. This system differs from traditional EEG systems in that rather than using metal disc electrodes and goopy gel, the electrodes are embedded in sponges that are soaked in an electrolyte solution. It uses high input impedances, which means that it’s very quick to put on. An experienced technician can get the “net” on in 10-15 minutes, whereas putting on 128 electrodes in low impedance systems takes about 60-90 minutes. Wearing the “net” is also very comfortable. NetStation software is available for data recording and analysis.
The other system is a 64 channel system made by Advanced NeuroTechnology. This system is very compact and portable, which makes it ideal for studies where it’s easier to go to research subjects than to have them come to us. Another advantage to this system is that the electrodes are “actively shielded”, which means that the EEG recordings are much less susceptible to interference from electrical noise in the environment, such as that generated by lights and computer monitors. EEG is often recorded in a specially shielded booth to avoid this contamination, but with the actively shielded electrodes there’s no need for this. ASA software is available for data recording and analysis (including source localization).
As well we have a Polhemus FasTrak digitizer and ANT eetrak software for encoding the 3 dimensional locations of each electrode on a person’s scalp. This is extremely useful when attempting source localization since, rather than using a model of where each electrode “should” be on a generic-shaped head, we have highly accurate and individualized information. Combined with a structural MRI of the subject’s head and brain, this can lead to markedly improved abilities to determine where in the brain the scalp-recorded EEG was generated.
The NCIL is equipped with an RF-shielded, sound attenuating booth for EEG recording, made by Eckel Industries of Canada. This is where the EGI system is located. It’s very quiet in there, which is nice for minimizing distractions as well as for the occasional nap.