The Korean Journal of Physiology
- Volume 24 Issue 1
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- Pages.103-113
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- 1990
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- 0300-4015(pISSN)
Response of Brachial Muscles to Neck Rotation in the Decerebrate Cat
제뇌(除腦) 고양이의 경부(頸部) 회전자극에 대한 상완근(上腕筋)의 반응
- Lee, Dong-Sun (Department of Orthopaedic surgery, Wonkwang University School of Medicine) ;
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Park, Byung-Rim
(Department of Physiology, Wonkwang Univeristy School of Medicine) ;
- Kim, Sang-Soo (Department of Orthopaedic surgery, Wonkwang University School of Medicine)
- Published : 1990.06.30
Abstract
The role of cervical proprioceptors in the control of body posture was studied in bilaterally labyrinth-ectomized, decerebrate cats. The animals were suspended on hip pins with the neck extended horizontally. With this placement the EMG activities of extensor and flexor muscles of the upper extremities were observed by means of sinusoidal head rotator. The rotator can induce two kinds of neck movement: The one is 'pitch' which describes a rotatory neck motion to transverse axis of the body and mainly occurs at skull-C1 (atlantooccipital) joint and the other is 'roll', side-to-side relation of the neck to longitudinal axis, whose center is C1-C2 (atlanto-axial) joint. The following results were obtained. 1) Responses of EMG activity were closely dependent on the rotatory range of the neck. And the EMG activity was not changed during sustained neck torsion, eliciting a typical tonic neck reflex. 2) On pitching movement, the head-up rotation produced the excitation of bilateral triceps muscles, whereas the head-down rotation produced the inhibition. And the response of bilateral biceps muscles was the opposite to that of triceps. 3) On rolling movement, the side-up rotation of the head produced the excitation of ipsilateral triceps muscles and the inhibition of contralateral ones. And the response of biceps muscles was the opposite to that of triceps. 4) The minimum requirement of motion to evoke EMG activities in the upper extremities was