EEG Lab Introduction - Wofford Collegewebs.wofford.edu/steinmetzkr/Teaching/Lab/EEG.pdf · 11/15/12...
Transcript of EEG Lab Introduction - Wofford Collegewebs.wofford.edu/steinmetzkr/Teaching/Lab/EEG.pdf · 11/15/12...
11/15/12
1
+
EEG Lab
+EEG
n In 1929, Hans Berger attached electrodes to the scalp of human subjects and recorded systematic fluctuations in voltage over time
n These fluctuations are called the electroencephalogram (EEG)
11/15/12
2
+EEG
n Result of postsynaptic potentials from many thousands of neurons
n These potentials spread as they travel from the brain to the scalp
n The maximum voltage on the scalp may be very far from the site of the neural activity
+EEG
n Synchronized oscillations n Synchronized activity over a
network of neurons
Epilepsy
11/15/12
3
+EEG Waves n Beta
n Asynchronous waves n 18-30 Hz, lower
amplitude n Awake and directed
attention
n Alpha: 10-12 Hz n Awake but at rest n Stage 1 NREM
n Theta n 4-7 Hz; Large amplitude n Stage 2 and 3 NREM
n Delta n Slow waves, < 4 Hz
frequency n Stage 3 and 4 NREM
+How do we quantify our data?
n Integration: RMS (Root Mean Squared) n Square:
n Square Samples 1-30
n Mean:
n Average all of those points
n Gives you one number for that whole window
n Smoothing
n Root:
n Take the square root of that number (to scale it back down)
n Repeat for the next 30 samples
n Gives you a running window – absolute value average