EEG rhytms

Question 1

Delta

Answer 1

Less than 4 Hz.
Large in amplitude. Deep sleep.

Question 2

Theta

Answer 2

4-7 Hz
Both during sleep and waking states.

Question 3

Alpha

Answer 3

8-13 Hz
Largest over the occipital cortex.
Associated with quiet, waking states.
A voltage that goes up and down approximately 10 times per second (i.e. each cycle lasts approximately 100 ms).

Question 4

Mu

Answer 4

8-13 Hz
Largest over motor and somatosensory areas.

Question 5

Beta

Answer 5

15-30 Hz
Associated with alertness and mental activity.

Question 6

Gamma

Answer 6

30-90 Hz
Relatively fast waves. An activated or attentive cortex.

Question 7

Spindles

Answer 7

8-14 Hz
Brief waves. Associated with sleep.

Question 8

Ripples

Answer 8

80-200 Hz
Recorded in the hippocampus and neocortex. Essential role in memory. There are physiological ripples and pathological ripples. Pathological ripples are considered biomarkers for epilepsy

Question 9

K complex

Answer 9

High-amplitude sharp wave. Occasionally observed during stage 2 sleep.