[Abstract Title]. - Society for Neuroscience

Support: NIH Grant 1T32 AR050959
NIH Grant R01 HD40984
NIH Grant R01 NS 35130
Title: Motor command for activating and relaxing leg muscles originates from different parts of
the brain
Authors: *L. ZHANG 1 , V. SIEMIONOW 1 , K. KISIEL-SAJEWICZ 3,1 , J. ANDRISH 2 , G. H.
YUE 1 ;
1 Dept.of Biomed. Engin., 2 Dept. of Orthopaedic Surgery, Cleveland Clin., Cleveland, OH; 3 Dept.
of Kinesiology, Fac. of Physiotherapy, Univ. Sch. of Physical Educ. in Wroclaw, Wroclaw,
Poland
Abstract: Electroencephalogram (EEG)-derived movement-related cortical potential (MRCP)
preceding a voluntary motor activity represents cortical command to initiate the activity. This
study investigated whether MRCP locations in the brain for activating and relaxing the knee
extensor muscles are different. This information is currently not available. Twelve young healthy
volunteers (24.2 ± 5.8 years, 9 men) participated in this study. Subjects performed intermittent
isometric knee extensions (45 trials) using their right leg at 20% maximal voluntary contraction
level. Each contraction lasted 10 s with a 10-s rest period between adjacent contractions. EEG
data were recorded from the scalp using a 128-channel system during all contractions along with
knee extension force and muscle EMG signals. MRCP was derived by force-triggered averaging
of the EEG data from each channel and measured at times right before the contraction and
relaxation. The EEG Data were processed and the sources (locations of the MRCP in the brain)
were estimated using the BESA software. The sources were localized on x (left-right), y (frontback),
and z (top-bottom) coordinates in the Talairach standard brain. MRCP before the
EMG/force onset was quantified and considered as the command for activating the muscles and
that before the muscles relaxing from the contraction was regarded as the command for ceasing
the contraction. The averaged MRCP locations on the y axis were -18.2 (in frontal lobe) for the
activation and -38.4 (in parietal lobe) for relaxation. The locations on the x axis (-10.5 for
activation and -10.2 for relaxation) were in the left hemisphere and similar between the two
conditions. The average locations on the z axis (55.4 for activation and 50.3 for relaxation)
indicate that the MRCP source for relaxation was deeper (towards the neck) compared with
activation. This study provides first-time information showing that the primary control area
generating the command to initiate voluntary knee extension is in the frontal lobe near the motor
cortices and that to relax the extension is in the parietal lobe close to the sensorimotor integration
regions. Detailed analysis is underway to pinpoint exact command locations for the muscle
activation and relaxation activities. These findings are important for guiding sports training,
sports medicine practice, and neuromuscular function rehabilitation.
Disclosures: L. Zhang, None; V. Siemionow, None; K. Kisiel-Sajewicz, None; J. Andrish,
None; G.H. Yue, None.