Exercise 20: Elerctroencephalography (EEG)
A record of the electrical activity of the brain.
below 4 Hz; slow, large waves; normally seen during deep sleep
rhythm generally apparent when an individual is in a relaxed, nonattentive state with the eyes closed
correlated to the alert state; usually about 15 to 30 Hz
What is meant by the term alpha block?
Suppression of the alpha rhythm
List at least four types of brain lesions that may be determined by EEG studies.
Epileptic foci, infections, tumors, blood clots
What is the common result of hypoactivity or hyperactivity of the brain neurons?
How was alpha block demonstrated in the laboratory experiment?
By clapping your hands, which caught the attention of the subjects.
What was the effect of mental concentration on the brain wave pattern?
Should have increased the frequency of the brain waves from the level of the alpha rhythm.
What effect on the brain wave pattern did hyperventilation have?
Produced a fast, irregular pattern
Observe the average frequency of the waves you measured for each rhythm. Did the calculated average for each fall within the specified range indicated in the introduction to encephalograms?
The average should fall within the normal range.
Suggest the possible advantages and disadvantages of using electroencephalography in a clinical setting.
EEG is a useful tool in the clinical setting to assess cerebral activity in generalized brain regions. Because EEG is indirectly recording, via the scalp, the activity of millions of nerve cells simultaneously, it is less effective in assessing the function of very specific regions of the brain.