Friday, February 3, 2012
On this day in 1821, Elizabeth Blackwell, the first woman to earn a medical degree in the United States, was born (thank you, this link). On this day in 2012, I test my first participant for my master’s dissertation. Today begins a very (very very) long relationship between myself and the EEG lab at Goldmsmiths’ College.
Referring back to this post about my thesis, I’ll be using EEG recordings to compare musicians’ and non-musicians’ melodic pitch expectations. We’re also using some auxiliary physiological signals like skin conductance, heart rate, and muscle activity, to see what we find.
I’m actually quite nervous for my first recording–there are so many things to remember when doing EEG recordings, and although I’ve been trained and I’ll have the always helpful postdoc at my side, I hope everything runs smoothly. Luckily, I’ve chosen one of my friends to be the guinea pig, so she won’t mind if things don’t go quite as planned.
To ease my nerves, let’s discuss electroencephalography (EEG). In an EEG recording, you’re using electrodes to record the brain’s electrical signals from the scalp. The participant wears a cap with lots of holes in it, and we fill those holes with conductive gel, and then snap the electrodes into place.
We also place electrodes above and below the eye, on each temple, and on the earlobes. These serve as references and help us identify any eye movements or muscle tension that can cause crazy looking artefacts on the recordings.
We’ll also be recording heart rate from an electrode placed on near the sternum, muscle activity from the forearm, and skin conductance from fingertips. There are a few papers that show relationships between these physiological responses and expectancy in music. All in all, it’s a whole lot of signals to record! Plus, the entire process of paperwork, preparing the cap and electrodes, the actual experiment, and clean-up takes about 3 hours. Hence my incredibly devoted relationship with the lab.
Regardless of all the time that goes into a single recording, it’s really amazing to see a brain working right there on the computer screen. You can tell when people start to get sleepy, or when they clench their jaws, and hopefully we’ll be able to see when they’re surprised about a pitch in a melody.
I need 50 participants, so if you’re planning on being in London in the next few months, I can plan a lovely afternoon for you!