摘要:

AbstractAxonal transport techniques were used to define the organization of projections from the forebrain to the paraventricular (PVH) and supraoptic (SO) nuclei of the hypothalamus in the adult rat. First, injections of a retro‐gradely transported fluorescent tracer, true blue, were placed in the region of the PVH, and the distribution of retrogradely labeled cells was charted. Then, the autoradiographic method was used to confirm the results of the retrograde transport experiments, to describe the route taken by inputs to the PVH and SO, and to determine the distribution of each projection within the various subdivisions of the nuclei that have been recognized previously on the basis of cytoarchitectonics, efferent projections, and immunohisto‐chemistry.The results can be summarized as follows. First, direct projections to the PVH arise from all areas of the hypothalamus (except the SO, the medial and lateral mammillary nuclei, and the magnocellular preoptic nucleus), and from the subfornical organ and the bed nucleus of the stria terminalis. Second, every forebrain region projecting directly to the PVH appears to innervate cell groups in parvocellular parts of the nucleus that in turn project to the neurohemal zone of the median eminence, and to autonomic centers in the brainstem and spinal cord. In addition, each input has a unique distribution within the parvocellular division. Third, relatively few regions in the forebrain project directly to magnocellular neurosecretory parts of the PVH, and are thus in a position to influence directly the release of posterior pituitary hormones. These regions (each of which also projects to the parvocellular division) include the dorsomedial nucleus of the hypothalamus, the median preoptic nucleus, the subfornical organ, and the bed nucleus. Therefore, inputs from the hippocampal formation, amygdala, and lateral septum that have been shown to influence the magnocellular neurosecretory system appear to be relayed by way of short projections from other parts of the hypothalamus (including perhaps parvocellular parts of the PVH) and from the bed nucleus. Fourth, most of these cell groups innervate preferentially either oxytocinergic (dorsomedial and bed nuclei) or vasopressinergic (subfornical organ) parts of the magnocellular division of the PVH. Only the projection from the median preoptic nucleus appears to be distributed uniformly over parts of the magnocellular division in which oxytocin‐ and vasopressin‐con‐taining cells are concentrated. And fifth, each region that preferentially innervates either oxytocinergic or vasopressinergic neurons in the PVH also preferentially innervates the same cell type in the SO (which does not contain a distinct parvocellular division). The results indicate that the coordination of neuroendocrine and autonomic responses from the PVH is mediated at least in part by a complex series of neural inputs, each of which innervates more than one functional subdivision within th

ISSN:0092-7317    

DOI:10.1002/cne.902180202

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe mode of termination of primary afferent fibres within the superficial dorsal horn of the spinal cord was studied with anterograde tracing methods in normal rats and in animals which had been treated with capsaicin (50 mg/kg. s.c.) shortly after birth. In normal animals following injections of horseradish peroxidase (HRP) into lumbar dorsal root ganglia L4, L5, L6, a Golgi‐like filling of primary afferent fibres was seen consistently within laminae I, II, and III of the dorsal horn. Several types of lamina related arborisations were observed, depending upon the survival time after HRP injection. At the earliest survival time (1–2 days) a punctate granular labelling was found in laminae I and II inner (IIi). At 3 days survival a Golgi like labelling of primary afferent axons occurred and three tiers of arborisation were seen within laminae I, II outer (IIO), and II inner (IIi), respectively. By 7 days after injection this pattern was considerably reduced and there was coarser fibre labelling within laminae I, IIO, and III.When these tracing experiments were repeated in capsaicin‐treated rats in which up to 90%of unmyelinated fibres had been destroyed, evidence for a considerable loss of some inputs and rearrangement of the remaining fibres was found. At 3–5 days survival the axonal labelling within laminae I and IIiwas severely depleted yet some input, particularly to lamina IIO, was present. At 7 days survival deep fibre labelling within lamina III now extended well into lamina II.Mapping of the primary afferent input following3H‐proline injections into the dorsal root ganglion and subsequent autoradiographic processing confirmed that primary afferents terminated throughout the dorsal horn but most heavily in two bands within laminae I and IIi. These two dense layers of termination were not present in capsaicin‐treated animals, suggesting that they corresponded to areas of unmyelinated primary afferent fibre input.These data, taken together with histochemical observations on the distribution of substance P and fluoride‐resistant acid phosphatase (FRAP)‐containing primary afferents, suggests that the earliest‐labelled fibre systems (3days) were unmyelinated and replaced at 7 days by predominantly A6 myelinated fibres. It is further suggested that of the three tiers of C fibre terminations seen at 3 days, the most superficial corresponds in part to those primary afferents that can be stained for substance P within lamina I while the most ventral tier within lamina IIiare those primary afferents containing FRAP. The presence of the two temporally distinct fibre systems also suggests that laminae I and IIo, receive both C and A6 primary afferent input while lamina IIi, receives o

ISSN:0092-7317    

DOI:10.1002/cne.902180203

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractHorseradish peroxidase (HRP) was injected in relatively massive amounts to cover most, or portions, of opercular striate cortex in four macaques. Absence of transcallosal or circumventricular labelling, plus discrete and consistent retrograde labelling in other areas in the four cases, assured the validity and specificity of the observations. Numerous labelled cells in regions directly bordering striate cortex, however, were excluded from the analysis because of the possibility of uptake consequent to physical diffusion. With this exception, all labelled cells were counted at roughly 2‐mm intervals for one case with extensive unilateral injection of HRP. Even excluding the closely circumstriate population, the totals indicate that more than 30% of the afferent input to striate cortex arises from nongeniculate sources. Four areas of neocortex together make up about one‐fourth of the total afferents: superior temporal sulcus 17.1%;inferior occipital area, 6.1%; intraparietal sulcus, 0.4%;and parahippocampal gyrus, 0.3%. Other areas projecting to striate cortex include claustrum, pulvinar, nucleus paracen‐ tralis, raphe system, locus coeruleus, and the nucleus basalis of Meynert. Cells of the latter were particularly striking with their very heavy uptake of HRP, and, even in cases of minimal effective injection, were scattered throughout an extensive area from the posterior edge of the globus pallidus passing rostrally beyond the chiasm and into the nucleus of the diagonal band. On the basis of their distribution and known cholinergic affinity, it is argued that this group also includes the cells labelled in and around lateral hypothalamus and cerebral peduncle, and that as a whole the group constitutes a cholinergic counterpart of the diffusely projecting monoaminergic systems. It seems possible that the basalis projection at first follows a forni cal‐subcallosal pathway to reach striate cortex via callosoperforant

ISSN:0092-7317    

DOI:10.1002/cne.902180204

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe inferior colliculus in the barn owl contains three subdivisions: the central (ICC), external (1CX), and superficial (ICS) nuclei. The nuclei are distinguished on the basis of their cyto‐ and myeloarchitecture, connectivity, and physiological properties. The ICC may be further divided into dorsal (ICCd) and ventral (ICCv) parts. Auditory fibers ascending in the lateral lemniscus enter the ICCd and ICCv, but not the ICX or ICS. The ICX receives its auditory input from the ICC. The ICC and ICX in owls are similar in position, anatomy, connectivity, and physiology to the ICC and ICX in mammals, suggesting that these structures are homologous. Units in the ICC are organized to potopically, whereas units in the ICX are organized according to the locationns of their spatial receptive fields. This implies that a transformation from tonotopic to a spatiotopic organization takes place in the ICX of the ow

ISSN:0092-7317    

DOI:10.1002/cne.902180205

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe optic tectum of the owl contains a topographic representation of auditory space. We have investigated the source of this space‐mapped auditory activity by using retrograde tracing with horseradish peroxidase. The major source of auditory input to the optic tectum is the ipsilateral external nucleus of the inferior colliculus (ICX), which is known to contain a map of auditory space also. Additional minor projections originate in the superficial nucleus of the inferior colliculus and the nucleus isthmi parvocellularis. There is no apparent projection to the optic tectum from the contralateral ICX or any other brainstem auditory nucleus. The projection from the ICX to the optic tectum is point‐to‐point: rostral ICX projects to rostral tectum, caudal ICX to caudal tectum, dorsal ICX to dorsomedial tectum, and ventral ICX to ventral tectum. Thus, the space‐mapped organization that exists in the ICX is passed on by topographic projections to the optic

ISSN:0092-7317    

DOI:10.1002/cne.902180206

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe central projections of hairplates and groups of campaniform sensilla of various parts of the locust head, neck, and thorax are compared. Receptors with approximately the same peripheral location (e.g., dorsal head, wing, or proximal leg) tend to exhibit similar central projection patterns. Specificity of the projections due to different morphological types of sensory neurones may influence shape and extent of segmental ramifications; this is observed with receptors of the proximal leg joints in particular.

ISSN:0092-7317    

DOI:10.1002/cne.902180207

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractNeurons that provide sensory and motor innervation of extraocular muscles in the monkey have been identified and localized by retrograde transport of horseradish peroxidase (HRP). Injections of HRP into individual extraocular muscles of rhesus or pig‐tail monkeys labeled pseudounipolar neurons that were localized within the ipsilateral semilunar ganglion. The distribution of labeled neurons within the ganglion was consistent with its somatotopic organization as the majority were found within the ophthalmic subdivision. Absence of labeled neurons within either the trigeminal mesencephalic or spinal nucleus was in agreement with previous findings in the cat (Porter and Spencer, '82). Intracranial transection of the ophthalmic nerve prior to muscle injection eliminated all labeling within the ganglion. These data indicate that the extraocular muscles can be selectively deafferented in order to examine the potential role(s) of proprioception in the neural control of eye movements.Injections of HRP into the extraocular muscles also resulted in the la beling of individual motoneuron populations. Each extraocular muscle was found to receive solely unilateral innervation, with contralateral representation of only the superior rectus and superior oblique. Within the oculomotor nucleus there was a moderate topographic segregation of individual motoneuron populations. Primate medial rectus and inferior rectus representations, while at variance with the classical descriptions (Warwick, '53), were consistent with those obtained in contemporary tracer studies (Büttner Ennever and Akert, '81; Spencer and Porter, '81). Superior rectus motoneurons were distributed along the medial aspect of the contralateral nucleus, with the predominant representation at caudal to midnuclear levels. Inferior oblique motoneurons filled the gap lateral to those of the superior rectus and ventral to medial rectus (dorsal subgroup) and inferior rectus representations at their respective levels. Following injections of the lateral rectus and superior oblique labeled motoneurons were found within the ipsilateral abducens nucleus and contralateral trochlear nucleus, respectively. Superior oblique motoneurons were strictly confined to the well‐defined neuronal borders of the trochlear nucleus. Those innervating the lateral rectus, in addition to lying within the abducens proper, extended ventrolaterally from the nucleus to form a discrete ventral abducens nucleus. Our data provide a complete description of the innervation pattern of primate extraocular muscles which is based upon contemporary tracer techniques. These findings include the first demonstration of the localization of monkey first‐order afferent neurons which subserve extraocular muscle proprioc

ISSN:0092-7317    

DOI:10.1002/cne.902180208

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe neuronal distribution of 7‐aminobutyric acid (GABA) transaminase (GABA‐T), the enzyne which metabolizes GABA, has been mapped in rat brain. The method involves staining for newly synthesized GABA‐T by the previously established nitro blue tetrazolium technique in animals killed 8–48 hours after administration of gabaculine, an irreversible inhibitor of GABA‐T. Neuronal staining is obscured by staining of other elements if initial suppression is inadequate or survival times postgabaculine are too long. With appropriate conditions, GABA‐T‐positive neuronal somata can be widely detected. The stained cells include neuronal groups previously reported to be GAB Aergic on the basis of glutamate decarboxylase (GAD)‐col‐chicine immunocytochemistry and other methods, i.e.: Purkinje, basket, Golgi, and stellate neurons of the cerebellum; basket and stellate neurons of the hippocampus; granule and periglomerular cells of the olfactory bulb; magnocellular neurons of the hypothalamus; and neurons of the striatum, pallidum, entopeduncular nucleus, cortex, medial septal area, diagonal band, substantia innominata, reticular nucleus of the thalamus, substantia nigra, and dorsal raphe. Other cells that stain intensely for GABA‐T and may be GABAergic include neurons in the midlateral septal area, accumbens, the central medial and basal. nucler of the amyugdala, zona in certa, the brainstem reticular formation, central gray, interstitial nucleus of Cajal, and various thalamic nuclei including the periventricular, intralami‐nar, rhomboid, and subparafascicular. Known non‐GABA neuronal groups are negative for GABA‐T staining under these conditions, reinforcing the hypothesis that GABA neurons are far more GABA‐T i

ISSN:0092-7317    

DOI:10.1002/cne.902180209

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.902180201

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY