PMC6921188_01
Case 1 EMG study. Back average of 50 trials. APB: Abductor pollicis brevis, LevSc: Levator scapulae; Trap: Trapezius, SCM: Sternocleidomastoid.
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The same pattern was repeated non-rhythmically with a frequency of approximately 12 per minute (Fig. 1).
Case 1 BP. A: Back average of voluntary movements. At Cz it is possible to see a clear BP potential that is time locked to the contraction of the APB. B: There is no BP when the back average is done triggered on the anterior neck muscles burst.
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PMC6921188_02
Examples of contractions observed during the recording of case 2. The gray line shows the beginning of the contraction. Although there is a pattern, there is also some variability in the latency of the different muscles. tParaS: thoracic paraspinal, lParaS: Lumbar paraspinal, LevSc_R: Levator scapulae right, SupS_R: Supraspinalis right, Pect_R: Right pectoralis, Pect_L: left pectoralis, Triceps_R: right triceps, Biceps_R: Right biceps.
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The muscles of the back had some more variability, but it was important to note that in all the trials, there was initially a contraction of the lumbar paraspinals (in some cases at the same time as the right pectoralis, in other cases up to 30 ms later), followed by thoracic paraspinals going against a rostro-caudal propagation (Fig. 3).
A: Back average of voluntary movements. At Cz it is possible to see a clear BP potential that is time locked to the contraction of the APB. B: There is no BP when the back average is done triggered on the pectoralis major muscle.
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