摘要:

AbstractAscending thalamotelencephalic visuaJ pathways that terminate in specific telencephalic regions have been described in all reptiles studied. Although the anatomical data suggests that such telencephalic regions may play a role in visual processing in reptiles, few behavioral data are available. In the present study, the effects of destruction of either the core nucleus (CN) of the dorsal ventricular ridge (telencephalic terminus of the tectothal‐amofugalpathway) or the dorsal cortex (telencephalic terminus of the retino‐thalamofugal pathway) on visual discriminative performance in the turtle were examined. Following extensive bilateral destruction of the CN, turtles were severely impaired in their performance of both a simultaneous pattern discrimination and a simultaneous visual intensity discrimination. The extent of the discriminative impairment was found to be specifically correlated with the amount of CN damage. In contrast to the effects of CN lesions, lesions of the dorsal cortex had no evident effect on the performance of either a simultaneous pattern discrimination or a simultaneous visual intensity discrimination. The present results suggest that, as in birds and mammals, telencephalic visual areas play an important role in visual functions in reptiles. As in at least some birds (such as pigeons), the telencephalic terminus of the tectothalamofugal visual pathway appears to play a larger, or at least more readily measurable, role in visual discrimination than does the telencephalic terminus of the retinothalamofugal path

ISSN:0092-7317    

DOI:10.1002/cne.902180102

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractOntogeny of the cholecystokinin‐8 (CCK) neuron system in the fore‐brain and upper brainstem of the rat was investigated by means of indirect immunofluorescence. CCK ceils and fibers first appeared in the developing ventral tegmental area and in the primordium of the medial forebrain bundle, respectively, at gestational day 15 (12–14‐mm embryos). From that time, CCK cells appeared in various areas of the forebrain and upper brain‐stem until birth and reached the maximum content at postnatal day 10. After postnatal day 10, although CCK cells tended to decrease slightly in number, colchicine treatment in the adult rats brought out numerous CCK cells in the same areas. In contrast, although CCK fibers developed only slightly during the fetal period, marked development was seen after birth, particularly between postnatal days 5 and 10. After that time, as the rats grew, CCK fibers continued to increase in number and formed a meshwork of varying density in various areas of the forebrain and upper

ISSN:0092-7317    

DOI:10.1002/cne.902180103

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThis study describes the distribution of organ‐specific populations of vagal afferent fibers within the nucleus of the solitary tract (nTS) in the pigeon. The central projections of vagal sensory neurons were visualized by the centripetal and trans‐ganglionic transport of horseradish peroxidase from either the central cut ends of peripheral vagal branches or from HRP injection sites in peripheral vagal target tissues. This paper also includes a detailed description of the cytoarchitectural organization of the nTS in the pigeon based on studies of Nissl‐stained material.Vagal afferent fibers that innervate different peripheral target organs are partially segregated within cytoarchitecturally distinct subnuclei of the nTS. Gastrointestinal afferents, for example, project primarily to medial subnuclei. On the other hand, pulmonary, and on the basis of earlier studies, cardiovascular afferents, project primarily to lateral subnuclei, Moreover, the rostral to caudal distribution of gastrointestinal afferents corresponds to the rostrocaudal topography of the gastrointestinal tract. In addition, our data demonstrate a projection of gastrointestinal afferents to the lateral descending tract of the trigeminal nerve that appears to terminate in the external cuneate nucleus.The cytoarchitectural organization of visceral representations within the pigeon nTS corresponds closely to recent descriptions of this cell group in mammals. Comparison of our results with studies of the central connections of nTS neurons suggests that the subnuclear distribution of organ‐specific vagal afferents within nTS plays a critical role in the organization of ascending and descending visceral afferent p

ISSN:0092-7317    

DOI:10.1002/cne.902180104

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractLesions were placed in the striaturn and the olfactory tubercle of 1‐day‐old rat pups. Control and experimental animals were raised to adulthood. Efferent projections of mesencephalic neurons were examined by injecting the retrograde tracers horseradish peroxidase or Fast Blue into the undamaged striata of some experimental animals. The survival of the mesencephalic dopaminergic neurons was monitored by using immunocytochemical localization of tyrosine hydroxylase. Small lesions in the caudate‐putamen had no appreciable effect on the survival of tyrosine hydroxylase‐containing neurons in the mesencephnlon, but the density of dopaminergic terminals adjacent to the lesion increased in the remaining caudate‐putamen. Striatal lesions that involved an estimated area of more than one‐third resulted in loss of dopamine neurons of the substantia nigra compacta. Rostral lesions in the striatum affected mostly rostrally positioned neurons in the substantia nigra. Dorsal lesions of the caudate‐putamen resulted in disappearance of dorsal A9 neurons. Reduction of the A10 and A8 dopamine neuron groups occurred if the neonatal lesions involved the olfactory tubercle and nucleus accumbens. Some tyrosine hydroxylase‐containing neurons persisted even after the largest lesions. These dopaminergic neurons formed a crossed ni‐grostriatal pathway which was confirmed by retrogradely transported tracers. The density of this crossed projection in the adult appeared unaffected by the neonatal lesion.We concluded that dopaminergic neurons form topographically ordered projections with their targets in the newborn rat. Rearrangement of these fibers appeared limited, but compensatory increase of axon terminal density was evident in partially lesi

ISSN:0092-7317    

DOI:10.1002/cne.902180105

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe characteristics of the islands of Calleja complex (ICC) in the basal forebrain of the rat were studied with immunohistochemistry, histofluorescence, acetylcholinesterase staining, India ink vascular perfusions, electron microscopy, and steroid autoradiography. The ICC contains clusters of granule cells and associated medium‐sized and large cells in the surrounding neuropil of the olfactory tubercle and septum‐nucleus accumbens interface. The ICCs were found to contain monoamine fibers (dopamine and norepi‐nephrine), neuroactive peptide fibers (leu‐enkephalin, met‐enkephalin, substance P, cholecystokinin, luteinizing hormone‐releasing hormone), acetyl‐cholinesterase‐containing somata and dendrites, and medium‐sized and large cells that concentrate [3H] estradiol.The specific overlap and combination of putative neurotransmitters in separate compartments of the ICC suggest that these structures contain striatum‐ and pallidumlike components. Striatumlike regions are defined as the zone in the rim regions of the ICC and are innervated predominantly by dopamine and cholecystokinin inputs. Pallidumlike regions are defined as the synaptic zone near the medium‐sized and large cells of the cap and core regions of the ICC and they are innervated predominantly by enkephalin, substance P, and gamma aminobutyric acid inputs. The morphology, connections, and neurotransmitter relationships of the ICC, therefore, resemble classical Striatopallidal systems.The additional presence of substances involved in the reproductive neuroendocrine systems (luteinizing hormone‐releasing hormone, estradiol‐binding cells), especially in the medial ICC, suggest that some ICC are involved in an endocrine corticostriatopallidal system. These endocrine systems resemble other neocortically and allocortically originating corticostriatopallidal systems in terms of their cell types, connections, and neurotransmitter systems. A functional role for the ICC in extrapyramidal

ISSN:0092-7317    

DOI:10.1002/cne.902180106

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.902180101

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY