Distinct brain activation patterns for human maximal voluntary eccentric and concentric muscle actions

• Published in: Brain research Vol. 1023; no. 2; pp. 200 - 212
• Main Authors: Fang, Yin, Siemionow, Vlodek, Sahgal, Vinod, Xiong, Fuqin, Yue, Guang H.
• Format: Journal Article
• Language: English
• Published: London Elsevier B.V 15.10.2004; Amsterdam Elsevier; New York, NY
• Subjects: Adult; Biological and medical sciences; Biomechanical Phenomena; Brain Mapping; Central nervous system; Cerebral Cortex - physiology; CNS; Concentric contraction; Eccentric contraction; Elbow - physiology; Elbow flexor muscle; Electroencephalography - methods; Electromyography - methods; Electrophysiology; Evoked Potentials, Motor - physiology; Fatigue; Fundamental and applied biological sciences. Psychology; Humans; Male; Maximal voluntary contraction; Movement - physiology; Movement-related cortical potential; Muscle Contraction - physiology; Muscle, Skeletal - physiology; Musculoskeletal Physiological Phenomena; Reaction Time - physiology; Time Factors; Vertebrates: nervous system and sense organs; Eccentric contraction; Concentric contraction; CNS; Maximal voluntary contraction; Elbow flexor muscle; Motor systems and sensorimotor integration; Movement-related cortical potential; Human; Central nervous system; Concentric movement; Electrophysiology; Muscle contraction; Encephalon; Evoked potential; Body movement; Flexor muscle; Elbow; Eccentric movement
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/j.brainres.2004.07.035

Eccentric muscle contractions generate greater force at a lower level of activation and subject muscles to more severe damage than do concentric actions. A recent investigation has revealed that electroencephalogram (EEG)-derived movement-related cortical potential (MRCP) is greater and occurs earlier for controlling human eccentric than concentric submaximal muscle contractions. However, whether the central nervous system (CNS) control signals for high-intensity or maximal-effort eccentric movements differ from those for concentric actions is unknown. The purpose of this study was to determine whether the MRCP signals differ between the two types of maximal-effort contractions. Eight volunteers performed 40 maximal voluntary eccentric and 40 maximal voluntary concentric elbow flexor contractions on a Kin-Com isokinetic dynamometer. Scalp EEG signals (62 channels) were measured along with force, joint angle, and electromyographic (EMG) signals of the performing muscles. MRCP-based two-dimensional brain maps were created to illustrate spatial and temporal distributions of the MRCP signals. Although the level of elbow flexor muscle activity was lower during eccentric than concentric movements, MRCP-indicated cortical activation was greater both in amplitude and area dimension for the eccentric task. Detailed comparisons of individual electrode signals suggested that eccentric movements needed a significantly longer time for early preparation and a significantly greater magnitude of cortical activity for later movement execution. The extra preparation time and higher amplitude of activation may reflect CNS activities that account for the higher risk of injury, higher degree of movement difficulty, and unique motor unit activation pattern associated with maximal-level eccentric muscle actions.