R. Nashmi et al., EEG RHYTHMS OF THE SENSORIMOTOR REGION DURING HAND MOVEMENTS, Electroencephalography and clinical neurophysiology, 91(6), 1994, pp. 456-467
The aim of this study was to determine what motor behaviors or conditi
ons were associated with an increased occurrence of beta activity in t
he sensorimotor region of human subjects. EEG recordings were obtained
from 8 electrodes symmetrically arranged around C3, with 3 cm interel
ectrode spacing. The electrode montage allowed calculation of the Lapl
acian operator at two positions, C3, and C3(c), overlying the hand are
a of the motor cortex and of the somatosensory cortex, respectively A
variety of tasks involving right-hand movements of different levels of
complexity, attention and preparation were performed. The correspondi
ng EEG power spectra were subsequently computed for frequencies betwee
n 7 and 50 Hz. Repetitive hand movements alone (either drawing circles
or writing one's signature) did not result in significantly increased
beta activity in the sensorimotor region compared to relaxed conditio
ns. However, both motor preparation and focused attention, whether mov
ements were performed or not, were associated with an increase of high
frequency beta activity (30-50 Hz) in the sensorimotor region. Theref
ore, the facilitatory effect of attention and motor preparation and no
t the functional activation of the sensorimotor cortex by hand movemen
ts was associated with an increase in synchronized fast beta activity.