Selective elimination of cerebellar output in the genetically dystonic rat.
ABSTRACT The genetically dystonic (dt) rat, an autosomal recessive mutant, exhibits a progressive motor syndrome that resembles the generalized idiopathic dystonia seen in humans. Even with supportive measures, dt rats die before reaching maturity. A total cerebellectomy that includes the dorsal portions of the lateral vestibular nuclei (dLV) eliminates the dystonic motor syndrome of the dt rats, greatly improves motor function, and prevents early death. The selective elimination of cerebellar nuclei was used to determine the cerebellar components critical to the mutant's motor syndrome. Bilateral electrolytic and/or excitatory amino acid lesions of the medial cerebellar nucleus, nucleus interpositus, lateral cerebellar nucleus and dLV were created in separate groups of 15-day-old dt rats. Rats were observed for the presence of abnormal motor signs (falls, twists, clasps, pivots) and tested on several measures of motor performance (activity, climbing, righting, homing, hanging) before surgery and again on Postnatal Day 20. All nuclear lesions produced significant improvements in motor function and decreases in the frequency of abnormal motor signs. Electrolytic lesions of the dLV were associated with the greatest improvements.
- [show abstract] [hide abstract]
ABSTRACT: The cerebellofugal projections in the contralateral ascending pathway of the brachium conjunctivum (B.C.) in the rat have been investigated in 23 animals using the Fink-Heimer technique to demonstrate the axonal degeneration resulting from complete B.C. lesions (7), partial B.C. lesions (14) and control lesions dorsal to the B.C. (2). All of the degeneration resulting from the concomitant involvement of the structures surrounding the B.C. is accounted for in terms of known fiber pathways and from the results in the control experiments. The contralateral ascending pathway ascends rostrally from the decussation of the B.C. through the ventromedial midbrain tegmentum to the diencephalon. In the midbrain, cerebellofugal fibers terminate heavily throughout the red nucleus including the nucleus minimus, while others pass dorsolaterally and dorsomedially from the ascending tract to terminate in adjacent midbrain nuclei. The dorsolaterally directed fibers terminate in the midbrain reticular formation,the stratum griseum profundum of the superior colliculus, the anterior pretectalnucleus and the nucleus of the posterior commissure; the dorsomedially directed fibers terminate in the principal oculomotor nucleus, the nucleus of Darkschewitsch, interstitial nucleus of Cajal and the central gray matter. A considerable number of the cerebellofugal fibers proceed more rostrally within the prerubral field and enter the thalamus by two routes. Most follow a direct subthalamic course within field H of Fore1 and after contributing fibers to the zona incerta, enter the caudal pole of the ventromedial nucleus (Vm) of the thalamus to terminate throughout Vm and the ventrolateral complex (Vl). Others enter via the internal medullary lamina and terminate throughout the parafascicular and central lateral nuclei. A small number of cerebellothalamic fibers form a commissural projection to V1 on the opposite side.The finding that the cerebellothalamic projections to the ventral nucleus are distributed throughout Vm and V1 establishes the Vm-V1 complex as the homologue in the rat of the ventral anterior and ventral lateral nuclei in the primate thalamus.The Journal of Comparative Neurology 05/1978; 178(3):495-517. · 3.66 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: A protocol has been established for the staining of myelin in frozen sections. While the new method is relatively fast and simple, it eliminates the problems routinely encountered with myelin stains such as blotchiness and uneven staining. Modifications were introduced into the procedures in order to obtain excellent fiber staining results on a wide variety of tissue.Journal of Neuroscience Methods 03/1983; 7(3):289-94. · 2.11 Impact Factor
- Scandinavian Journal of Statistics. 01/1979; 6:65-70.