NROB60H3 Chapter Notes - Chapter 19: Cataplexy, Excessive Daytime Sleepiness, Melatonin
23 Jan 2013
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Document Summary
Eeg is the classical way for recording brain rhythms in the cerebral cortex. Eeg measures voltages generated by currents that flow during synaptic excitation of the dendrites of many pyramidal neurons in the cerebral cortex. The amplitude of an eeg depends on how synchronous the activity of the underlying neurons. An alternative way to record the rhythms of the cerebral cortex is with magnetoencephalography (meg). It is better than eeg when localizing the sources of neural activity in the brain, particularly when they are deep in the brain. Eeg and meg can record rapid fluctuations of neural activity, unlike fmri or. Eeg and meg measure direct neuronal activity, while fmri and mri measure blood flow or metabolism. Eeg can be classified differently according to frequency range: Beta rythms: fastest, 15-30 hz, and signal an activated cortex. Alpha rythms: 8-13 hz, associated with quiet, waking states. Theta rythms: 4-7 hz and occur during some sleep states.
