PSYCH 2NF3 Lecture : Class Lecture Notes 22-35 - March 6-Apr 8 - PSYCH 2NF3
9 Sep 2013
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Electrophysiological investigations of the brain: electroencephalogram (eeg) Non-invasive place electrodes on scalp; standard electrodes for specific locations. Wide fluctuations depending on the activity occurring. Predominantly recording spontaneous electrical activity of the brain. Summed up activity of population of neurons and synapses not recording action potentials or single channels; Eeg patterns (figure right) ranges and locations of brain you must remember; frequency and amplitude changes are inversely proportional: beta normal recordings (awake, alpha (relaxed) Aroused state more asynchronous, beta activity. Relaxed start to see alpha waves. Deep sleep synchronous, theta, delta pattern (left); relaxed, eyes closed, synchronized pattern, alpha waves; (right) eyes open, desynchronized, high frequency, low amplitude, beta waves. Alpha block conversion of synchronized alpha waves to desynchronized beta waves on activation of cortex: eg/ when the subject opens the eyes or when the eyes are shut but the subject is performing some mental task. Observing eeg hard to determine normal arousal or epilepsy.
