摘要:

AbstractIn spite of repeated demonstrations by degeneration technics, nigrothalamic fibers have been regarded with some skepticism. Attempts were made to trace‐ nigral efferent projections in the monkey by autoradiographic technics. Tritiated amino acids (L‐leucine, L‐lysine and L‐proline), injected into portions of the substantia nigra (SN), labeled cells in four regions, designated as, (1) rostrolateral, (2) caudolateral, (3) rostromedial and (4) central.Rostrolateral nigral neurons transported radioactive label preferentially and abundantly to thalamic nuclei; localized isotope was found in parts of three thalamic nuclei, the medial part of the ventral lateral nucleus (VLm), the magnocellular part of the ventral anterior nucleus (VAmc), and the paralaminar part of the dorsomedial nucleus (DMpl).Lateral neurons in the caudal half of the SN transmitted radioactive label to the same thalamic nuclei as rostrolateral nigral neurons. Isotope transported to portions of the striatum was modest and localized. Radioactive label taken up by large cells in the caudal third of the SN was transported to portions of the striatum, but not to thalamic nuclei.Labeled nigral neurons in the medial two‐thirds of the rostral half of the SN, and in the middle third of the central part of the SN, transported the label mainly to parts of the caudate nucleus and putamen. In these animals modest radioactive label was seen in VLm and VAmc, but not in other thalamic nucleus.There was no evidence that nigral neurons project to the subthalamic nucleus. No radioactive transport from nigral neurons was detected in the superior colliculus, the midbrain tegmentum, or the red nucleus, and none was transported to more caudal brain stem nuclei.Nigrothalamic fibers arise particularly from cells in rostral and lateral parts of the substantia nigra. While some cells in other parts of the nigra project to thalamic nuclei, these appear scattered and less numerous. Large cells in caudal parts of the SN do not project to thalamic nuclei. These observations confirm nigrothalamic projections to VLm and VAmc, and identify a new nigral projection to part of the dorsomedial nucleus of the thalamus (DMp1). No nigral efferent fibers project to any of the intralaminar thalam

ISSN:0092-7317    

DOI:10.1002/cne.901650402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractThe ascending projections of the cuneiform nucleus in the cat were traced by autoradiography in the transverse and sagittal planes following stereotaxically placed injections of3H‐leucine. The ascending fibers are almost exclusively ipsilateral and enter the diencephalon as a wide radiation. At the mesodiencephalic junction fibers enter the nucleus of the posterior commissure and pretectal nuclei, and others cross in the posterior commissure to distribute to these structures on the contralateral side. More ventrally directed fibers distribute to the fields of Forel and then spread into the posterior hypothalamus and zona incerta. At the caudal level of the ventral thalamic group, the ascending fibers diverge and follow two separate courses. One division of fibers continues forward beneath the ventral thalamic group and distributes to the zona incerta and dorsal hypothalamic area. It rapidly diminishes in size as it attains more rostral levels where it is found in the bed nuclei of the stria terminalis and the anterior commissure. Other fibers of this division spread laterally to innervate the ventral lateral geniculate nucleus, the lateral hypothalamus, and preoptic area, and still others follow the entire conformation of the thalamic reticular nucleus. The second division of fibers ascends through midline and intralaminar nuclei, completely encircling the mediodorsal nucleus, which is uninnervated except for a small ventral region. The distribution of this division is heaviest to the paraventricular, parafascicular, and central dorsal nuclei. Neither division is conspicuous rostral to the anterior commissure. No projections to neostriatum or specific thalamic nuclei were eviden

ISSN:0092-7317    

DOI:10.1002/cne.901650403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractTo resolve inconsistencies in experimental studies which use reduced silver methods to detect cerebellar climbing fiber sources within the brain stem, an evaluation of the temporal course of degeneration was undertaken. The paraflocculus of the rabbit is uniquely situated within the temporal bone and connects with the corpus cerebelli via a stalk passing through a bony foramen. A unilateral electrolytic lesion deafferented the paraflocculus without disturbing blood supply or causing other damage (18 animals). Comparatively, another group of unilateral lesions was placed at the dorsolateral pontomedullary junction, adding significantly to the cortical area deafferented (12 animals). Animals of each group were killed at successively longer intervals commencing at 18 hours, and a modified Fink‐Heimer impregnation process was applied to the cerebellar cortex and opposite‐sided controls.In parafloccular lesions, degeneration was detected at 24 hours in the climbing fibers of the molecular layer. At successively longer intervals, degeneration became increasingly evident in granule layer and white matter. Subsequent to dorsolateral pontomedullary lesions, climbing fiber degeneration was first observed in the molecular layer at 24 hours and was clearly evident there at 36 hours. By 72 hours degeneration had reached the white matter, meanwhile disappearing in the molecular layer where it was first seen.Using techniques of Nauta‐Fink‐Heimer to display secondary climbing fiber degeneration in cerebellar cortex, it was found that too long post‐operative intervals could preclude its detection, since in both groups of animals it commenced earlier and disappeared sooner in the molecu

ISSN:0092-7317    

DOI:10.1002/cne.901650404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractWe have traced central nervous pathways controlling bird son in the canary using a combination of behavioral and anatomical techniques. Unilateral electrolytic brain lesions were made in adult male canaries whose son had been previously recorded and analysed on a sound spectrograph. After severral days of postoperative recording, the birds were sacrificed and their brains processed histologically for degeneration staining with the Fink‐Heimer technique. Although large lesions in the neostriatum and rostral hyperstriatum had no effect on song, severe song deficits followed damage to a discrete large‐celled area in the caudal hyperstriatum ventrale (HVc). Degenerating fibers were traced from this region to two other discrete nuclei in the forebrain: one in the parolfactory lobe (area X, a teardrop‐shaped small‐celled nucleus) and a round large‐celled nucleus in the archistriatum (RA). Unilateral lesions of X had no effect on song; lesions of RA, however, caused severe song deficits. Degenerating fibers from RA joined the occipitomesencephalic tract and had widespread ipsilateral projections to the thalamus, nucleus intercollicularis of the midbrain, reticular formation, and medulla. It is of particular interest that direct connections were found onto the cells of the motor nucleus innervating the syrinx, the organ of song production. Unilateral lesions of n. intercollicularis (previously implicated in the control of vocal behavior) had little effect on song.One bilateral lesion of HVc resulted in permanent (9 months) and complete elimination of the audible components of song, although the bird assumed the posture and movements typical of song. Preliminary data suggest that lesions of the left hemisphere result in greater deficits than lesions of the right one. This finding is consistent with earlier reports that the left syrinx controls the majority of song components. Results reported here suggest a localization of vocal control in the canary brain with an overlying left hemispheric

ISSN:0092-7317    

DOI:10.1002/cne.901650405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractUsing the autoradiographic method in the zebra finch (Poephila guttata), areas of the brain were identified which contain cells which accumulate testosterone or its metabolites after intramuscular injection of tritiated testosterone. Among these areas are the caudal nucleus of the hyperstriatum ventrale, nucleus intercollicularis of the midbrain, and the tracheosyringeal portion of the hypoglossal nucleus of the medulla (nXIIts). These three are known to control or influence androgen dependent song and other vocalizations of passeriform birds, and nXIIts is composed of the motoneurons innervating the vocal (syringeal) muscles. Other areas containing hormone‐concentrating cells are the medial preoptic area, nucleus periventricularis magnocellularis of the hypothalamus, dorsal infundibular layers, dorsomedial thalamus, lateral septum, magnocellular nucleus of the anterior neostriatum, periventricular medial neostriatum, nucleus taeniae of the archistriatum, and ventral paleostriatum augmentatum. Accumulation by cells in the preoptic area, hypothalamus, and limbic forebrain is consistent with a general vertebrate pattern of distribution of brain cells which accumulate sex steroids. Some of these same areas may be involved in the control of androgen dependent events such as courtship, copulation, aggression, and feedback regulation of the hypophysi

ISSN:0092-7317    

DOI:10.1002/cne.901650406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractThe central projections of the external gustatory system in bullhead catfish were examined using orthograde degeneration and retrograde transport of horseradish peroxidase (HRP) techniques.Both large and small cells were observed in the anterior ganglion which contains a mixture of elements from the trigeminal, facial and anterior lateral line nerves. Some of the large cells on the lateral margin of the ganglion were found to belong to the lateral line system. No separation of trigeminal and facial nerve connections could be made.Using HRP, the relation between the barbels and specific ganglion regions was determined. The dorsalmost portion of the ganglion received recurrens nerve inputs (from taste buds on the trunk); the rostromedial portion of the ganglion, from the nasal barbel nerve; and the ventral portion of the ganglion, from the maxillary and mandibular barbel nerves.The facial lobe (similar to part of the n. solitarius) was found to be divided into lobules by fascicles of nerve fibers. The lateral lobule received input only from the dorsal‐most part of the ganglion (recurrens nerve: trunk receptors); the intermediate lobule from the rostro‐lateral part of the ganglion (nasal barbel); and the medial lobule from the ventral areas of the ganglion (maxillary and mandibular barbels).Thus a topographical relationship exists between the different taste receptor groups and their locus of representation in the facial lobe. The trunk receptors connect to the lateral lobule; the nasal barbel receptors to the intermediate lobule, and the maxillo‐mandibular receptors to the medial l

ISSN:0092-7317    

DOI:10.1002/cne.901650407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.901650401

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY