Brain Imaging vol2 (Week 11)
This week, we conducted a reaction time experiment similar to an experiment in an exercise in an earlier week. This time the experiment took place at the Aalto Behavioural Laboratory facilities and consisted of an EEG measurement. I volunteered to be a subject, and so got an EEG cap on my head and everyone poking my head with syringes trying to get the best contact and conductivity between my scalp and the electrodes. Fun times!
Before the actual experiment, we demonstrated for example the effect of biting my teeth together or blinking my eyes a lot had on the signal. I didn’t have any idea how long the actual experiment would be, but to be honest, it seemed like an eternity. I guess listening to beeping or looking at flashing squares isn’t the most exciting thing in the world. I hope we got some useful data and that my brain is not somehow broken. – V
On the other side of the wall, in the observation room, we chatted about brain research and looked at the brain wave graphs the EEG was measuring as they appeared on the screen. V completed the task and the required repeats, and repeats, and repeats… and it only took like 30minutes! The hard part was getting the cap to respond correctly, as the interaction between hair and electrode gel was not a simple matter.
As S and I are both writing our bachelor’s thesis concerning fMRI right now, it was interesting to see EEG in action, as the two brain imaging methods are often compared. EEG’s time resolution is superior to that of fMRI, but the spatial resolution of fMRI gives us far more accurate data on the location of the activity. EEG measures direct brain activity, but locating it is almost impossible and the signal is full of noise. Functional MRI on the other hand is limited due to measuring BOLD, which changes in response to the brain activity, etc…
Both methods clearly have their advantages and disadvantages, and new methods are constantly being developed, so hopefully in the future V won’t need to get her scalp full of gel when we want to see the brain waves of her blinks. – P
P inserting mind-control liquid into V’s brain. Just kidding, it’s just gel between the EEG cap and the head.