Muscle-afferent projection to the sensorimotor cortex after voluntary movement and motor-point stimulation: An MEG study

• Published in: Clinical neurophysiology 2011-03, Vol.122 (3), p.605-610
• Main Authors: Onishi, Hideaki, Oyama, Mineo, Soma, Toshio, Kirimoto, Hikari, Sugawara, Kazuhiro, Murakami, Hiroatsu, Kameyama, Shigeki
• Format: Article
• Language: English
• Subjects: Adult; Biological and medical sciences; Data Interpretation, Statistical; Electric Stimulation; Electrodiagnosis. Electric activity recording; Electroencephalography; Evoked Potentials, Somatosensory - physiology; Female; Fingers - innervation; Fingers - physiology; Fundamental and applied biological sciences. Psychology; Humans; Investigative techniques, diagnostic techniques (general aspects); M70; Magnetoencephalography; Male; Medical sciences; MEF1; MEG; Middle Aged; Motor control and motor pathways. Reflexes. Control centers of vegetative functions. Vestibular system and equilibration; Motor Cortex - physiology; Motor-point stimulation; Movement - physiology; Muscle Contraction - physiology; Muscle, Skeletal - innervation; Muscle, Skeletal - physiology; Nervous system; Neurology; Neurons, Afferent - physiology; Somatosensory Cortex - physiology; Vertebrates: nervous system and sense organs; Voluntary contraction; Young Adult
• ISSN: 1388-2457; 1872-8952
• DOI: 10.1016/j.clinph.2010.07.027

Abstract Objective To investigate the projection of muscle afferents to the sensorimotor cortex after voluntary finger movement by using magnetoencephalography (MEG). Methods The movement-evoked magnetic fields (MEFs) after voluntary index-finger extension were recorded by a 204-channel whole-head MEG system. Somatosensory-evoked magnetic fields (SEFs) were recorded after motor-point stimulation was applied to the right extensor indicis muscle by using a pair of wire electrodes. Results The MEF waveforms were observed at 35.8 ± 9.7 ms after movement onset (MEF1). The most concentrated SEFs were identified at 78.7 ± 5.6 ms (M70), and the onset latency of M70 was 39.0 ± 5.5 ms after motor-point stimulation. The mean locations of the equivalent current dipoles (ECDs) of MEF1 and M70 were significantly medial and superior to that of N20m elicited by median-nerve stimulation. The ECD locations and directions of both MEF1 and M70 were concordant in the axial, coronal and sagittal planes. Conclusions MEF1 and M70 might be elicited by muscle-afferent feedback following muscle contraction. In addition, these ECDs may be located in area 4. Significance Motor-point stimulation is a useful tool for confirming the projection of muscle-afferent feedback to the sensorimotor cortex after voluntary movement.