摘要:

AbstractThe distribution of substance P (SP)‐containing neural processes in the ventral horn region of the human and monkey spinal cord was studied by staining for SP by the indirect antibody peroxidase‐antiperoxidase technique and by light and electron microscopic examination of stained material. Immunoreactive fibers and terminals were found in all major cell columns of the ventral horn in the human and monkey spinal cord, with the immunoreactive profiles in close apposition to motoneurons. The immunoreactivity was contained in synaptic knoblike (bouton) structures, in which the label was associated with small agranular vesicles, dense‐core vesicles, and mitochondria. The immunoreactive synaptic knobs formed synaptic junctions predominantly with dendrites. The labeled knobs were similar to “S” (agranular spheroid vesicles) and “G” (dense‐core vesicles) type bulbs described previously in the monkey ventral horn. Their location, mainly on the neuron dendrites and soma supports the physiological evidence that SP‐produced membrane depolarization is mediated primarily by a direct action of the neurochemical on the neuron rather than by a trans

ISSN:0092-7317    

DOI:10.1002/cne.902070402

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe relative somal and nuclear sizes of neurons in the lateral motor column (LMC) of adult and embryonic mouse brachial spinal cord were determined by light microscopic morphometry. Three genetically varying mouse strains, previously shown to differ in the development of a forelimb reflex pathway, were studied. In adults, the size distribution of somata, nuclei, and nucleoli were bimodal for each strain, indicating that there are two distinct size classes of LMC neurons. The size division between large and small LMC neurons differed among strains with more large LMC neurons occurring in strain CBA/CaJ than in either LP/J or C57BL/6J. In embryos, the growth of LMC cells was studied by determining the average area of nuclear profiles for specimens ranging in age from embryonic day 11 (E11) to 16. The average nuclear profile area increased significantly during this period in all three strains, and differences were found in the initial size and apparent rate of growth among strains. Early in development (E11‐12), strain differences in apparent cell size were: C57BL/6J>CBA/CaJ>LP/J, and this strain order corresponds to observed strain differences in the onset of reflexogenesis and synaptogenesis (Vaughn et al., ′75). Later in development (E16), strain differences in apparent cell size were: CBA/CaJ>LP/J≥C57BL/6J, and this relationship corresponds to a more rapid increase of presumptive afferent synapses in CBA/CaJ than in the other two strains between E15 and E16. Possible causal relationships among neuronal size, growth, and synaptogenesis are suggested by these strain differ

ISSN:0092-7317    

DOI:10.1002/cne.902070403

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe development of organelles within presumptive alpha motor neuronal somata was studied by electron microscopic morphometric analysis. Cells with large nuclei were selected for sampling from the lateral motor column of the brachial spinal cord of mouse embryos ranging in age from embryonic day 11 (E11) through E16. The first objective was to compare the cytodifferentiation of alpha motor neuronal somata among three genetically different strains of mice that differ in the development of forelimb reflex behavior and associated pathway synaptogenesis (Vaughn et al., ′75). On the basis of multiple linear regression analyses, no significant differences were found among strains for either the initial levels or rates of cytodifferentiation. As a result, the data were combined for all three strains to analyze organelle changes during early neuronal development. The average areas of perikaryal cytoplasm and nuclei increased significantly. In addition, the relative areas of nucleoli, mitochondria, Golgi complexes, and rough endoplasmic reticulum increased, while the relative areas of heterochromatin and “free” ribosomes decreased. There were significant increases in the number of mitochondria and Golgi complexes per unit area of perikaryal cytoplasm. The average size of mitochondria appeared to increase during development, but was significantly smaller in adult alpha motor neurons than in embryonic specimens. In contrast, the average size of individual Golgi complexes was relatively constant throughout embryonic development, as well as in the adult. In general, the cytodifferentiation of alpha motor neurons appeared to progress in a relatively constant, linear fashion between E11 an

ISSN:0092-7317    

DOI:10.1002/cne.902070404

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe generation and settling patterns of large and small lateral motor column (LMC) neurons were compared in the spinal cords of three inbred strains of mice by means of tritiated thymidine autoradiography. No significant strain differences were observed for the number of large LMC cells (presumptive alpha motor neurons) that were heavily labeled on each injection day, although there were significant strain variations for this measure with regard to small LMC neurons (presumed gamma motor neurons and interneurons). The generation of both large and small LMC neurons began at the same time, but peak production of large cells preceded that of the small neurons. There were no strain differences observed for this relationship between the large and small cells. These findings indicate that the LMC, from the time of its initial formation contains cells destined to become large and small neurons. The positions of large and small neurons within the adult LMC relative to their times of origin (settling patterns) were analzyed statistically. A significant ventrodorsal sequence for early‐to‐late generated cells was observed for both large and small LMC neurons. No significant strain difference were found in the analysis of settling patterns. A ventrodorsal settling pattern also has been described for amphibia (Prestige, ′73) and, in conjunction with the proximodistal sequence of limb development describedby other investigators, the ventrodorsal sequence could play a key role in the development of motor neuronal somatotopic organiz

ISSN:0092-7317    

DOI:10.1002/cne.902070405

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

年代:1982

数据来源: WILEY

摘要:

AbstractConnections of two telencephalic vocal control nuclei, the hyperstriatum ventrale, pars caudale (HVc), and robust nucleus of the archistriatum (RA), were investigated in adult canaries. Methods used were transport of horseradish peroxidase and3H‐adenosine and silver staining of degenerating axons. Three nuclei project to HVc: medial nucleus magnocellularis ofthe anterior neostriatum (MAN), nucleus interfacialis (NIf) of midneostriatum, and nucleus uvaeformis (Uva) of the diecephalon. Uva also projects to NIf. NIf and Uva have not been described previously. HVc projects to area X of lobus parolfactorius, to RA, and to field Avalanche of hyperstriatum ventrale. Nucleus RA receives projections from HVc and from lateral MAN. All these projections are ipsilateral. No gross male/female differences were apparent in the projections to and from HVc. Uptake of HRP by cell somata in HVc following localized injections of this substance into RA or HVc suggests that HVc is composed of rostrocaudally organized clusters of cells, with little lateral communication between the

ISSN:0092-7317    

DOI:10.1002/cne.902070406

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

年代:1982

数据来源: WILEY

摘要:

AbstractSome sources of olfactory input to the opossum mediodorsal thalamic nucleus (MD) were identified by retrograde horserdish peroxidase and anterograde autoradiographic methods. One major source originated from the olfactorytubercle and a narrow strip of piriform cortex bordering the tubercle. The tubercle‐MD projection exhibited a definite spatial organization and included all except the most medial part of MD. The fact that the projection reached the most lateral and ventral extent of MD abutting the intralaminar complex suggests that the entire opossum MD may correspond to only the medial, magnocellular division in the primate and that the equivalents of both the parvocellular and paralamellar divisions may be absen

ISSN:0092-7317    

DOI:10.1002/cne.902070407

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe uptake of 2‐deoxyglucose (2‐DG) was employed to map functional activation of the central auditory pathway in the mongolian gerbil, during 85 dB SPL stimulation with pure tonal stimuli at frequencies of 0.75, 3.0, or 12.0 kHz. Pure tones produced foci of very high 2‐DG uptake, when compared to adjacent tissue, in the cochlear nucleus, superior olivary complex, and inferior colliculus. Less distinct areas of elevated 2‐DG uptake were seen in the dorsal and ventral nuclei of the lateral lemniscus, medial geniculate nucleus, and auditory cortex. Little or no change in the distribution of 2‐DG uptake was noted in the nucleus of the trapezoid body. The location of discrete regions of relatively high 2‐DG uptake varied systematically with stimulus frequency. The tonotopic organization demonstrated by 2‐DG mapping agreed well with the results of previous electrophysiological studies for most structures. However, in the inferior colliculus, stimulus‐evoked increases in 2‐DG uptake were found to occur in a fixed pattern of three to four bands across the central nucleus, which did not correspond to any previously reported anatomical or physiological organization. Pure tonal stimuli activated discrete portions of this banding pattern. Also, a small area at the ventromedial edge of the colliculus was more broadly tuned than other regions of the nucleus. It is concluded that 2‐DG uptake is well suited to theinvestigation of tonotopic organization. This technique reveals patterns ofactivation which have not been observed with

ISSN:0092-7317    

DOI:10.1002/cne.902070408

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe individual fine myelinated fibers of cutaneous mechanical nociceptors and “D‐hair” receptors were identified by electrophysiological recording with micropipette electrodes in cats and monkeys. Their intraspinal terminations were labeled by iontophoresing horseradish peroxidase intracellularly and subsequent diaminobenzidine histochemistry. These terminations were examined with light and electron microscopy to determine the nature and organization of their synaptic contacts.Myelinated fibers of the mechanical nociceptors became unmyelinated before exhibiting many enlargements that made multiple synaptic contacts in the marginal zone (lamina I) and lamina V. Pre‐or postsynaptic contacts were found only on enlargements. In the marginal zone of the cat, enlargements made simple axodendritic contacts or were scalloped, central terminals in glomeruli. In glomeruli, myelinated mechanical nociceptor enlargements were presynaptic to several dendritic appendages and postsynaptic to two different types of profiles. One type was interpreted as a presynaptic axon terminal, the other as a presynaptic, vesicle‐containing, dendritic appendage. In lamina V of the cat the nociceptor synaptic complexes were similar, but simpler, and only axonal profiles were found to be presynaptic to them. In the monkey marginal zone and deep nucleus proprius, myelinated nociceptor terminations formed the central element of glomeruli, which consisted of postsynaptic dendritic appendages and presynaptic axon terminals.D‐hair axons terminated in large numbers of enlargements in the nucleusproprius (laminae III and IV) and inner substantia gelatinosa (lamina III). Their large rounded enlargements formed the central terminals in glomeruli and were presynaptic to both ordinary and vesicle‐containing dendritic appendages; the presynaptic dendritic profiles also often contacted each other. Profiles interpreted as axonal in origin were the only terminals presynaptic to the primary ending within the D‐hair glomeruli.The results suggest that transfer of primary afferent information occurs only at enlargements of the primary fiber and that each primary fiber enters into more than one kind of synaptic arrangement. They also point out that synaptic glomeruli are common to functionally different types of primary afferent fibers and that the internal organization of glomeruli varies with the kind of primary fiber and the locus

ISSN:0092-7317    

DOI:10.1002/cne.902070409

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

年代:1982

数据来源: WILEY

摘要:

AbstractHorseradish peroxidase (HRP) gel implants in the frontal eye field (FEF) of macaque monkeys, processed with tetramethylbenzidine (TMB) neurohistochemistry and studied with darkfield microscopy, demonstrated bidirectional HRP labeling of the afferents and efferents of this cortical area. It was evident that among the entire scope of its inputs, the FEF received a prominent afferent projection from the nucleus of the optic tract (NOT, nucleus limitans) and the suprageniculate nucleus, and projected to a medial subdivision of NOT, sublentiform nucleus, nucleus of the pretectal area, nucleus of the posterior commissure, and the rostral periaqueductal gray. The directafferent projections to FEF from NOT could provide a route for visual inputto reach FEF via the pretectum without first going to the visual cortex. The efferents probably represent the pathway through which FEF influences pupillary dynamics known to accompany, or occur independently of, eye movements.

ISSN:0092-7317    

DOI:10.1002/cne.902070410

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

年代:1982

数据来源: WILEY

摘要:

AbstractRats were undernourished from the 16th day of gestation to 25 postnatal days of age and then weaned on to an ad libitum diet. Around 35 days of age, 12 previously undernourished (PU) male pups were assigned to an “enriched environmental condition” (EC) and 12 to an “isolated environmental condition” (IC). Well‐fed controls were similarly assigned. After 30 days in these conditions all rats were killed by perfusion with fixative.Body and “forebrain” weights, and forebrain lengths and widths, were determined for each animal. The forebrains were subsequently embedded in paraffin wax and serially sectioned. Ten sections, identified by subcortical landmarks, were taken from each brain and used for cortical depth measurements. The whole experiment was carried out on two separate occasions.In both the well‐fed and PU groups the EC rats were between 3% and 9% lighter in body weight and between 4% and 9% heavier in “forebrain” weight than IC animals. A two‐way analysis of variance (two‐way ANOVA) indicated significant effects of nutrition and environment on body and forebrain weights but no significant interaction. Nutrition, but not environment, also had significant effects on “forebrain” width and length measurements.For the well‐fed groups, only one section out of all those measured from the two experimental series showed a significant effect of environment onthe cortical depth measurements.For the PU groups, in experiment one the cortical thickness of the EC rats was significantly greater than their IC counterparts in four out of theten sections analyzed. In the second experiment only two sections exhibitedsignificant results. In contrast to experiment one, these showed that the IC rats had a slightly but significantly thicker cortex than the EC rats. A two‐way ANOVA of the data on cortical depths showed no significant effects of, or interaction between, nutrition and environment.These observations are discussed in the context of previously publishedresults on the effects of a differential environment

ISSN:0092-7317    

DOI:10.1002/cne.902070411

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

年代:1982

数据来源: WILEY