摘要:

AbstractThe autoradiographic method was used to compare the numbers of hormone accumulating cells in several brain regions in male and female zebra finches (Poephila guttata) after injection of tritiated testosterone. The brain regions examined were the caudal nucleus of the hyperstriatum ventrale (HVc), magnocellular nucleus of the anterior neostriatum (MAN), robust nucleus of the archistriatum (RA), nucleus intercollicularis of the midbrain (ICo), the tracheosyringeal hypoglossal motor nucleus (nXIIts), and periventricular magnocellular nucleus of the anterior hypothalamus (PVM). All but the last of these regions are thought to be involved in the control of vocalizations in passerine song birds. Males have significantly more labelled cells in HVc and MAN. In RA, there is no difference in total percentage of labelled cells, but there is a sex difference in size distribution of labelled cells. No sex difference was detected in other brain regions. These differences are found when using a criterion for cell labelling which is based on the Poisson distribution, and the relative merits are evaluated of various quantitative criteria used in the analysis of steroid autoradiograms. The magnitude of the observed sex difference may be influenced by several biasing factors, yet the sex difference persists when corrections are applied to eliminate the biases, indicating that the sex difference is not an artifact of autoradiographic procedure. The magnitude of the sex difference in hormone accumulation has certain implications for the process of sexual differentiation of the brain.

ISSN:0092-7317    

DOI:10.1002/cne.901890302

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe organization and projections of the presumed homologue of the mammalian corpus striatum, the ventrolateral area (VLA) of the telencephalon, were investigated in the reptileCaiman crocodilus. The caiman VLA was divided into two major cell fields on the basis of cytoarchitectonic criteria: a rostromedial small celled field (VLA s.c.) and a large celled field occupying the dorsal, lateral and ventrocaudal portions of the VLA (VLA l.c.). Histochemical results indicate that the VLA s.c. contains high levels of both cholinesterase and catecholamine (CA) activity. An intense lacy plexus of CA‐containing axons and terminals was found in the VLA s.c. Far less CA activity was found within the VLA l.c. CA activity within the VLA appears to be derived primarily from axons of cells located within a large field of the midbrain tegmentum which is called in this report nucleus tegmenti pedunculo pontinus (TP). In the caiman the VLA also receives projections from the CA‐positive cells of the locus ceruleus and from serotonin containing cells of the midline raphe system.Anatomical experiments indicate that the VLA L.C. receives projections from neurons in the VLA S.C. and projects upon these subtelencephalic cell groups: the anterior and posterior entopeduncular nuclei (ENa and ENp), the ventral lateral and ventral medial thalamic areas (Avl and Avm), the dorsal nucleus of the posterior commissure (nDCP), and TP. The VLA s.c. projects upon TP. ENa neurons project upon cells in the VLA l.c. Cells of Avl and Avm receive both paleostriatal and cerebellar projections; Avl neurons project upon portions of the rostral telencephalon external to the VLA. NDCP neurons project upon the optic tectum.The organization and projections of the VLA inCaiman crocodilusare compared to the organization and projections of the paleostriatal complex of the pigeon (Karten and Dubbeldam, '73; Brauth, Ferguson and Kitt, '78) and to the mammalian basal ganglia. The following paleostriatal characteristics appear to be common features in these species and may represent retained characteristics derived from the common ancestor: (1) an ascending catecholaminergic system derived from neurons in the midbrain tegmentum; (2) projections from the basal striatum upon the catecholamine containing neurons of the midbrain tegmentum; (3) an intrinsic cholinergic system; (4) projections upon thalamic cell groups which are also in receipt of cerebellar projections and which project upon telencephalic regions external to the paleostriatum; (5) reciprocal connections between the paleostriatum and the ventral or subthalamus; and (6) projections upon cell groups which project to the optic tectum. The results are discussed in terms of the overall role of the basal ganglia in the neural control of behav

ISSN:0092-7317    

DOI:10.1002/cne.901890303

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

年代:1980

数据来源: WILEY

摘要:

AbstractAlthough much is known about the cell size changes that take place in the cat dorsal lateral geniculate nucleus as a result of visual deprivation, very little is known about the time course of either of these changes or the changes that occur during normal development. In addition, all previous studies of lateral geniculate nucleus cell size have been confined to the dorsal laminae A and A1 since the more ventral “C” laminae are impossible to identify in normal Nissl stained material. However, it is possible to extend the cell measurement data to laminae C, C1, and C2 by using autoradiographic techniques.Cross‐sectional area measurements of dorsal lateral geniculate nucleus cells were made in 47 normally reared kittens and 45 monocularly deprived kittens. All of the normal kittens and 39 of the 45 deprived kittens were studied during the first 70 days of postnatal life. Six deprived cats used to study the deprivatin induced changes in cell size in the “C” laminae were allowed to survive for longer periods.In normal kittens, lateral geniculate nucleus cells grow rapidly during the first four weeks of life. Cells in the deprived layers also grow rapidly during this time, however, at the end of the first month their growth stops and a slow shrinkage takes place over the next several weeks. In the ‘C’ laminae of deprived cats significant changes in cell size are confined to layer C.Although many of the deprived cats show greater deprivation induced changes in cell size in the binocular segment of the lateral geniculate nucleus than in the monocular segment, other cats show approximately equal changes in cell size in the two regions. In addition, some cats exhibit little, if any, deprivation induced change in lamina A cell size but do show quite severe cell shrinkage

ISSN:0092-7317    

DOI:10.1002/cne.901890304

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

年代:1980

数据来源: WILEY

摘要:

AbstractSystematic, quantitative studies are presented concerning the effects of visual deprivation and deafferentation on the growth of developing neurons in the dorsal lateral geniculate nucleus of the cat.Three sets of experiments are described. In the first set, kittens were enucleated monocularly at one week postnatal, and sacrificed at intervals that ranged from one day to 40 weeks. The second set was similar in design, but enucleation was done at four weeks postnatal. The third series of experiments did not involve enucleation. Instead, kittens were deprived by suturing the lids of one eye closed at the time of normal eye opening. They were then allowed to survive for periods of time that varied from two to 32 weeks. In addition, two cats were studied that had been deprived for 16 weeks by sewing the nictitating membrane across the cornea of one eye.Cell counts in the binocular segment of lamina A indicate that enucleation at one week postnatal leads to rapid cell death in the lateral geniculate nucleus. Approximately 27% of deafferented cells die during the first week after enucleation. Comparable cell loss also occurs in kittens enucleated at four weeks, but its onset is delayed until the second week following eye removal. There is no loss of neurons in the lateral geniculate in cats raised with monocular eyelid suture.Measurements of cell sizes show that the primary effect of visual deprivation or deafferentation is to alter the growth of lateral geniculate neurons. In deprived kittens or those enucleated at one week, affected cells continue to grow, albeit slower than normal, for 3–4 weeks postoperatively, at which time all further cell growth stops. Subsequently, there is no marked cellular atrophy, and deprived or deafferented neurons remain at approximately two‐thirds normal size. Enucleation at four weeks produces more severe effects. Eye removal arrests cell growth immediately, and approximately one month later deafferented neurons undergo significant atrophy. In these cats as well as in visually deprived animals, lateral geniculate cells receiving uncrossed input from the retina undergo greater changes in perikaryal size than neurons innervated contralaterally.In each set of experiments, rates of cell growth were compared in the binocular and monocular segments of lamina A ipsilateral and contralateral to the operated eye. No major differences were found between cells in the binocular segment and those in the dorsal portion of the monocular segment (that part of the monocular segment that lies adjacent to the lateral border of lamina A1). Furthermore, in enucleated cats, cell size changes throughout the deafferented monocular segment are equivalent, in general, to those in the binocular segment. By contrast, in visually deprived cats, neurons in the dorsal and ventral parts of the monocular segment respond differently. The present results suggest that a gradient of susceptibility to deprivation exists in the monocular segment since neurons located in the dorsal portion of the monocular segment are affected similarly to binocular segment cells, whereas cells in the ventral part ofthe monocular segment are resistant to deprivation.Neurons in the normally innervated binocular segment of lamina A in deprived or deafferented cats tend to grow somewhat faster than cells in normal animals, but do not attain larger than normal sizes. These experiments therefore do not provide evidence that normally innervated lateral geniculate neurons hypertrophy following monocular deprivation or enucleat

ISSN:0092-7317    

DOI:10.1002/cne.901890305

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

年代:1980

数据来源: WILEY

摘要:

AbstractFine structure of the noradrenaline (NA) nerve terminals in the dorsomedial portion of the nucleus tractus solitarii (NTS) was investigated by glyoxylic acid—potassium permanganate fixation method. The NA nerve terminals in this area contained a large number of small cored vesicles (SCV) (about 400‐600 Å in diameter) together with a few large cored vesicles (LCV) (about 1000 Å in diameter).The most frequent feature of NA nerve terminals observed in this area was axo‐dendritic contact. An axo‐axonic contact between NA and non‐NA terminals was also occasionally identified, while no axo‐somatic contact was found in this area as far as examined. At the contact zone between NA terminals and other neuronal elements, the following profiles suggestive of synapse‐like contact were identified: (1) somewhat dense material between contact membranes (intersynaptic filaments); (2) a slight accumulation of dense material adjacent to postcontact membranes; (3) disarrangement of contact membranes and enlargement of the space between these membranes; (4) aggregation of SCV and LCV to contact membranes.Finally it should be emphasized that NA nerve terminals often made a neuronal cluster or rosette with other neuronal elements, suggestive of a complicated role of NA

ISSN:0092-7317    

DOI:10.1002/cne.901890306

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

年代:1980

数据来源: WILEY

摘要:

AbstractSecondary trigeminocerebellar connections have been studied with HRP histochemistry in 25 sheep. The results indicate that almost all of the cerebellar cortex except flocculus, ventral paraflocculus and lobules I‐IV receives bilateral (mostly ipsilateral) fibers from the trigeminal nuclei.A topographical organization of trigeminocerebellar fibers is present. The mesencephalic tract nucleus projects to the anterior lobe, the simple lobule (HVI), lobules VI, VIII, and the dorsal paraflocculus. The ventral group of the princeps and spinal tract (mainly IDV) nuclei projects to all lobules studied in vermis and hemispheres. More dorsal parts of these nuclei have a more restricted projection field including the vermal lobules VI, VII, and IX and the hemisphere. Cells within and ventral to the motor nucleus of the trigeminal nerve were found labeled after injections into the anterior lobe, the simple lobule, and lobule IX. Labeled cells in the region of the nucleus ovalis and close to the solitary tract project to the simple and paramedian lobule and lobule I

ISSN:0092-7317    

DOI:10.1002/cne.901890307

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe primary sensory trigeminal system of Python is characterized by the presence of an additional nucleus which is involved in processing data obtained by infrared sensors. This so‐called lateral descending nucleus (LTTD) is strictly separated from the nuclei of the common sensory trigeminal system. The present study was undertaken in order to establish the relation between the two sensory trigeminal systems and higher brainstem structures. Further we studied whether the projections of these two systems remain separated at higher brainstem levelsIt is shown that the organization of particularly the thalamus is characterized by the presence of specific projection areas of each of the two trigeminal systems: (a) the ability of infrared perception is reflected particularly in the presence of an unique thalamic nucleus: the nucleus pararotundus and probably also in the enlargement of nucleus rotundus; and (b) distinct subnuclei in the thalamic ventral nuclear complex are related to the various nuclei of the common sensory trigeminal systemThe main ascending projection of LTTD runs via a distinct tract to the central gray layer (SGC) of the contralateral tectum mesencephali and the nucleus pararotundus (PR). Rostrally, numerous fibres decussate again via the tectal commissure and terminate ipsilaterally in the rostral part of SGC and in PRThe ascending projections of the common sensory trigeminal nuclei resemble those of mammals by gaining thalamic nuclei (ventral nuclear complex). No projections to the tectum nor to the striatum (like in birds) were observedThe two sensory trigeminal systems remain separately organised, in their projections as well as in their structure. No major connection between the two trigeminal systems is presen

ISSN:0092-7317    

DOI:10.1002/cne.901890308

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

年代:1980

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.901890301

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

年代:1980

数据来源: WILEY