THE EFFECTS OF HANDEDNESS AND TYPE OF MOVEMENT ON THE CONTRALATERAL PREPONDERANCE OF MU-RHYTHM DESYNCHRONIZATION

Event-related desynchronisation (ERD) of mu-rhythm was studied in 12 r ight-handed and 11 left-handed subjects during brisk and slow self-pac ed index finger movements of dominant and nondominant hand. Electroenc ephalogram (EEG) was recorded from the sensorimotor hand area of both hemispheres. The contralateral preponderance of mu-rhythm ERD in the p re-movement period showed the following changes: (i) the contrasts bet ween left- and right-finger movements were larger and earlier in the d ominant than nondominant hemisphere in both handedness groups; (ii) ri ght-handed subjects showed larger lateralisation of mu-rhythm ERD prio r to right-finger as compared to left-finger movements, whereas about equal contralateral preponderance for both sides was found in the left -handed; (iii) the lateralisation mu-rhythm ERD was lower prior to bri sk as compared to slow movements, especially in the left-handed subjec ts. The results demonstrate that hand dominance, handedness and type o f movement influence the proportion of pre-movement mu-rhythm desynchr onisation in the left and right peri-rolandic area.