摘要:

AbstractThe cerebellar cortex of adult hens contains a dense plexus of thin varicose nerve fibers which display a formaldehyde‐induced green fluorescence. This plexus is not distributed at random in the cortical layers. Within the granular layer the plexus forms a netlike pattern. The fiber branches, which have numerous varicosities, are predominantly oriented in the traverse plane of the folium. In the molecular layer the fluorescent plexus shows some variations in the convex, flat and concave portions of the folia. Many of the fluorescent branches are oriented parallel to the course of the folium. They arise from a T‐division of radially oriented axons resembling parallel fibers in Golgi sections.The meshes of the fluorescent plexus in the granular layer measure 10–60 μ. In the molecular layer (top of the folia) there are about 30 fluorescent fibers per 100 μ2.The fluorescent fibers originate from the locus coeruleus and form a rostral and a caudal bundle in the cerebellar peduncle.The mode of distribution of the fluorescent fibers in the cortical layers seems to depend on the organization of the innervated tissue. Light microscopy suggests that the aminergic fibers innervate more than one class of cerebellar

ISSN:0092-7317    

DOI:10.1002/cne.901620402

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe projection of the retina onto the optic tectum of the pigeon has been investigated using silver impregnation methods for degenerating axons and terminals, autoradiographic tracing, and the Golgi methods. Degenerating optic afferents distribute to sublaminae a–d and f of the stratum griseum et fibrosum superficiale over the whole tectum, but two major fields are observed. One occupies the caudal and ventral tectum (in which region laminar cytoarchitecture is marked), and the other rostral and dorsal tectum (where demarcation of cell laminae is relatively poor). Degeneration in the latter field is coarse and clearly distributes in a distinctly laminated fashion within the stratum griseum et fibrosum superficiale. In contrast, degeneration in the caudo‐ventral region is fine, and laminated distribution less clear. The evolution of the degeneration pattern over survival periods from 3 to 56 days suggests that these laminar distributions reflect the existence of several different types of optic terminal ramification present in all parts of the tectum. A selective laminar distribution of such optic afferent types correlates well with our own and other Golgi studies. The results of the autoradiography experiments are broadly compatible with these findi

ISSN:0092-7317    

DOI:10.1002/cne.901620403

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe fine structure of the superficial layer of the optic tectum of the pigeon,Columba livia, has been examined both in normal animals and after unilateral eye removal. Optic afferent terminals distributed throughout sublaminae IIa‐f, are principally concentrated at three depths in the retinoreceptive zone. At first, degeneration of optic afferent terminals occurs as swelling of synaptic vesicles and accumulation of neurofilaments and later as dense degeneration. There appear to be several classes of optic afferent terminals in the retino‐receptive zone, as would be expected from most previous studies of the avian tectum. The non‐optic components of the neuropil, which include glomerular and pleomorphic vesicle terminals, and the synaptic interrelationships between optic and non‐optic components are described. Optic afferent terminals mainly make synaptic contact with the branches of radial dendrites but also, in sublaminae IIb and IIc, with the dendrites of non‐radial cells. In sublamina IIc afferent terminals synapse onto the horizontal presynaptic dendrites of spindle cells and triplet synaptic arrays including optic afferent terminals, horizontal dendrites and radial dendrite profiles and radial dendrite profiles are found. This optic projection to non‐radial elements in IIb, c is discussed in relation to light microscope and electrophysiologi

ISSN:0092-7317    

DOI:10.1002/cne.901620404

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe maturation of the main and accessory olfactory bulb projections to the ventral forebrain of the golden hamster has been traced by using the Fink‐Heimer silver technique to stain degenerating axons and terminal arborizations after bulbectomy at different ages between birth and 33 days. In the youngest pups, long‐lasting degeneration argyrophilia (LLDA) is found in two regions of prepiriform cortex: at the level of the rostral tubercle and rostral amygdala. By five days of age the caudal region exhibiting a long‐lasting degeneration reaction extends from the middle of the olfactory tubercle, to the middle of the amygdala. The olfactory tubercle, medial and cortical amygdala and entorhinal cortex subsequently develop substantial LLDA at ages varying between 9 and 13 days.In a previous study (Leonard, '74b) the onset of LLDA in optic tract terminals in the superior colliculus was found to coincide with the age of eye opening and the onset of a stage of rapid synapse formation. Since different olfactory responses appear at different times during the golden hamster pup's first two weeks of postnatal life, it seems possible that the onset of LLDA in different regions of the olfactory projection at different ages may be related to the onset of different specific olfactory func

ISSN:0092-7317    

DOI:10.1002/cne.901620405

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

年代:1975

数据来源: WILEY

摘要:

AbstractAfferents to the substantia nigra from the neostriatum and globus pallidus were studied in the rat by means of the autoradiographic tracing technique.3H‐leucine was injected stereotaxically into either the globus pallidus or neostriatum. Twenty‐four hours later the axoplasmic transport of labelled proteins to the substantia nigra was studied by light and electron microscopic autoradiography. In animals used for electron microscopy, degeneration of dopaminergic cells in the substantia nigra was induced by intraventricular injection of 6‐hydroxydopamine 72 hours before sacrifice.After neostriatal injections, light microscopic analysis revealed heavy labelling of the globus pallidus and entopeduncular nucleus, but only background labelling of the subthalamic nucleus. There was preferential labelling of the zona reticulata of the substantia nigra, with significantly less labelling of the zona compacta.After pallidal injections, light microscopic analysis showed very light labelling of those parts of the caudate‐putamen in the vicinity of the injection site. There was intense labelling of the subthalamic nucleus and heavy labelling of the entopeduncular nucleus. The zona compacta of the substantia nigra was also heavily labelled. There was considerably less labelling of the zona reticulata.The electron microscopic analyses showed that after neostriatal injections, autoradiographic grains in the substantia nigra were located preferentially over boutons which terminated on normal dendritic processes. After pallidal injections, however, grains were preferentially located over boutons synapsing with degenerating dendritic processes. The degeneration produced in these dopaminergic processes by 6‐hydroxydopamine was invariably of the dark type. Except for the different association with degenerating vs. non‐degenerating dendrites, the subcellular distribution of autoradiographic grains in the substantia nigra was the same after injection into either the globus pallidus or caudate‐putamen. Approximately 80 percent of the grains were over axons or boutons which invariably made symmetrical synaptic contacts.These observations demonstrate the existence of a pallido‐nigral projection which terminates preferentially on dopaminergic cells in the pars compacta of the substantia nigra. They also confirm previous studies indicating that the strionigral projection terminates mainly in the pars reticulata. These terminations appear to be principally to non‐d

ISSN:0092-7317    

DOI:10.1002/cne.901620406

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

年代:1975

数据来源: WILEY

摘要:

AbstractThis autoradiographic study demonstrates a topical projection of the dorsal column nuclei to the contralateral nucleus ventralis posterior lateralis thalami and the accessory part of the inferior olive. In contrast to earlier anatomical studies the projections of the gracile nucleus and the internal cuneate nucleus proved to be independent and entirely contralateral.Fibers from the gracile nucleus terminate only in the lateral part of the nucleus ventralis posterior lateralis (VPL1) and from the internal cuneate nucleus only in the medial part of this nucleus (VPLm). Projections of the gracile nucleus to the contralateral inferior olive are restricted to the caudal one‐third of the medial accessory olive and the ventrolateral part of the dorsal accessory olive. The internal cuneate nucleus is only connected with the dorsomedial part of the rostral two‐thirds of the dorsal accessory olive.Our material does not allow conclusions about projections from the dorsal column nuclei to other thalamic nuclei and about rostrocaudal point to point relationships between the dorsal column nuclei and the thalamus or the inferior ol

ISSN:0092-7317    

DOI:10.1002/cne.901620407

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe spatial locations of several forebrain and midbrain fibre tracts have been compared across seven commonly used inbred, hybrid and outbred mouse strains using a series of electrolytic lesions of known postitions with respect to a stereotaxic instrument. Highly significant genetic variation was found in the positions of lambda, bregma and several major fibre tracts with respect to interaural zero; in the locations of fibre tracts with respect to bregma; and in the location of fibre tracts with respect to each other. It was demonstrated that stereotaxic coordinates of a structure for one strain could not be used for other strains. Errors resulting from improper alignment of the head in the instrument and histological artifact were also determined. These errors showed no significant group differences, but they revealed that within‐group variation was substantilly affected by such imperfection

ISSN:0092-7317    

DOI:10.1002/cne.901620408

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

年代:1975

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.901620401

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

年代:1975

数据来源: WILEY