ISSN:
1432-1106
Keywords:
Cervicocollic reflex
;
Muscle Compartmentalization
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary We have examined the cervicocollic reflex (CCR), evoked by horizontal rotation of the head of decerebrate cats, in the dorsal neck extensor muscle splenius. This muscle is divided into compartments which are innervated by three or four spinal segments; an analogous Compartmentalization may be observed in the CCR. When the CCR is evoked by rotation of the head about a vertical axis centered over C1–C2, the modulation of EMG activity is higher in the rostral than in the caudal compartments; in some cases, the rostral compartments can be modulated selectively. The rostrocaudal gradient of modulation is absent if the axis of rotation is shifted caudally to C4–C5. In muscles which had been completely detached from their origin and insertion, the pattern of activation of the CCR was similar to that observed in intact muscle, although the gain of the reflex fell by two thirds. This suggests that significant inputs to this reflex arise both from within splenius itself and from receptors outside this muscle. The typical CCR disappears if the C1–C4 dorsal roots ipsilateral to splenius are cut; furthermore, the reflex appears normal in animals with spinal transections above C1. A significant component of the CCR in splenius appears to be a segmental stretch reflex, originating partly in splenius and partly from receptors outside the muscle.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00237876
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