bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cholinergic innervation of the monkey amygdala: An immunohistochemical analysis with antisera to choline acetyltransferase
Authors: Amaral David G. , Bassett Julia L. 
Published: January 2005

AbstractThe organization of the cholinergic innervation of the macaque monkey amygdaloid complex was investigated by means of immunohistochemical techniques and either a polyclonal antiserum or a monoclonal antibody directed against the specific synthetic enzyme choline acetyltransferase (ChAT). Adjacent series of sections were processed histochemically for the demonstration of the degradative enzyme acetylcholinesterase (AChE) or for cell bodies with thionin. The density of ChAT immunoreactivity differed substantially among the various nuclei and cortical regions of the amygdala. In general, the distribution of ChAT immunoreactivity paralleled the pattern of AChE staining. One notable exception was the presence of AChE containing cell bodies in addition to AChE positive fibers within nearly all of the nuclear and cortical regions. In contrast, ChAT immunoreactivity was associated only with fibers and terminals.The highest density of ChAT immunoreactive fibers and terminals was consistently observed in the magnocellular subdivision of the basal nucleus. Staining was substantially less dense in the more ventrally situated parvicellular subdivision. Medially, in the adjacent accessory basal nucleus, immunoreactive fibers and terminals were densest in the magnocellular and superficial subdivisions and least prominent in the parvicellular subdivision. Of the deep nuclei, the lateral nucleus generally contained the least ChAT immunoreactive terminals and processes. Only its more densely cellular ventrolateral portion contained appreciable fiber and terminal staining.One of the more distinctive patterns of ChAT immunoreactivity was seen in the nucleus of the lateral olfactory tract. Here, ChAT positive fibers formed pericellular basket plexuses around unstained cell bodies. This unique pattern of staining was used to delineate the boundaries of the nucleus and indicated that it is present for much of the rostrocaudal extent of the amygdala. Another region of conspicuous staining on the medial surface of the amygdala was the sulcal portion of the periamygdaloid cortex. This region, associated with the sulcus semiannularis and bordering the entorhinal cortex, consistently contained dense immunoreactivity. The central nucleus also presented a somewhat idiosyncratic pattern of ChAT staining. The lateral subdivision had a diffuse distribution of immunoreactivity in which focal patches of more densely stained terminals and occasional fine fibers were embedded. In contrast, the medial subdivision contained a larger number of thicker, stained fibers without diffuse background labeling. Of the remaining amygdaloid nuclei, the amygdalohippocampal area contained dense ChAT staining, whereas progressively lighter staining was seen in anterior amygdaloid, posterior cortical, anterior cortical, and medial nuclei.
Cortical connections of areas 17 (V‐I) and 18 (V‐II) of squirrels
Authors: Kaas J. H. , Krubitzer L. A. , Johanson K. L. 
Published: January 2005

AbstractConnections of visual cortex in squirrels were investigated by placing WGA‐HRP injections, and in some cases fluorescent dyes, into area 17 (V‐I) or area 18 (V‐II). Results were related to architectonic fields determined in brain sections cut parallel to the surface of manually flattened cortex and to limited microelectrode mapping data. Injections in area 17 provided evidence for (1) a patchy pattern of horizontal intrinsic connections extending 1–2 mm form the injection site; (2) uneven, widely distributed connections with area 18 (V‐II) and adjoining occipital‐temporal (OT) cortex; and (3) callosal connections of large portions of area 17 with the 17/18 border zone. While restricted locations in area 17 had uneven interconnections over several mm of area 18, more rostral locations in area 17 related to more rostral locations in area 18, demonstrating a topographic tendency. Injections in area 18 revealed (1) zones of discontinuous connections with area 17 that followed a topographic pattern, (2) patches of intrinsic connections that spread over distances of up to 6–8 mm from the injection site; (3) two zones of uneven connections with OT cortex suggesting the locations of at least two visual areas, OTr and OTc; (4) connections with limbic cortex rostromedial to areas 17 and 18; (5) sparse connections with regions of temporal cortex lateral to OT; and (6) uneven callosal connections with area 18 and OT cortex. The widespread and unevenly distributed intrinsic callosal interconnection patterns of areas 17 and 18 contrast with the restricted excitatory receptive fields of neurons and the retinotopic patterns of representation in these fields. Although physiological evidence is presently lacking, the patchy connections suggest that areas 17 and 18 in squirrels are modularly organized.
Immunohistochemical localization of choline acetyltransferase in the chicken mesencephalon
Authors: Sorenson Eva M. , Parkinson David , Dahl June L. , Chiappinelli Vincent A. 
Published: January 2005

AbstractCholine acetyltransferase, a specific marker for cholinergic neurons, has been immunohistochemically localized in the mesencephalon and in the caudal diencephalon of the chicken. A complete series of transverse sections through the mesencephalon is presented.In the diencephalon, cholinergic fibers were found in the stria medullaris, the fasciculus retroflexus, and the ventral portion of the supraoptic decussation. The nucleus triangularis and the nucleus geniculatus lateralis, pars ventralis also contained cholinergic fibers. Small cholinergic cell bodies were found in the medial habenula. In the pretectum, cholinergic fibers innervated the nucleus lentiformis mesencephali and the tectal gray. The nucleus spiriformis lateralis also contained cholinergic fibers, while most of the cell bodies in the nucleus spiriformis medialis were cholinergic. In the mesencephalon, labelled fibers were found in the nucleus intercollicularis and in all layers of the optic tectum except the stratum opticum. The highest density of tectal cholinergic fibers was in the stratum griseum et fibrosum superficiale (SGFS), layer f. Radial cells located in SGFS, layer i were also cholinergic. In the isthmic nuclei, cholinergic fibers were found in the pars magnocellularis, while the pars parvicellularis and the nucleus semilunaris contained labelled cells. The oculomotor, Edinger‐Westphal, trochlear, and trigeminal motor nuclei all had cholinergic cell bodies. Cholinergic axons were present in the oculomotor and trochlear nerves. In the tegmentum, cell bodies were labelled in the nucleus mesencephalicus profundus, pars ventralis, while the nucleus interpeduncularis had dense cholinergic innervation.Our localization of cholinergic cell bodies and fibers has been compared with earlier autoradiographic and anatomical studies to help define cholinergic systems in the avian brain. For example, the results indicate that the chicken may have a cholinergic habenulointerpeduncular system similar to that reported in the rat. Establishing the cholinergic systems within the avian midbrain is important for designing future neurophysiological and pharmacological studies of cholinergic transmission in this region.
Quantitative analysis of the number and distribution of neurons richly innervated by GABA‐immunoreactive axons in the rat superior cervical ganglion
Authors: Wolff J. R. , Kasa P. , Dobo E. , Wenthold R. J. , Joo F. 
Published: January 2005

AbstractThe superior cervical ganglion of rats contains a considerable number of nerve fibers with GABA‐like immunoreactivity which show a nonuniform distribution within the ganglion. The topography of these fibers has been analyzed by using antibodies raised against GABA‐BSA‐glutaraldehyde complexes. GABA‐postive axons and axon varicosities accumulated around a subpopulation of principal ganglion cells forming basketlike patterns. These neurons richly innervated by GABA‐positive axons (RIG‐neurons) in turn were aggregated in patches with strong immunoreactivity. The size and packing desity of the patches containing RIG‐neurons and GABA‐positive axons approaching them had rostral‐to‐caudal and medial‐to‐lateral gradients. Similar patterns were found in right and left ganglia. In five ganglia, a quantitative analysis revealed on average 1,344 RIG‐neurons per ganglion representing about 5% of the total neuron population, with small variations (standard deviation 122) despite the highly variable shape of the ganglia. The distribution of RIG‐neurons resembles that of neurons sending their axons into the internal carotid nerve. To check this possible correlation, HRP was injected into the eye and applied to the transected external carotid nerve. Double staining for the retrogradely transported peroxidase and GABA immunohistochemistry revealed that RIG‐neurons formed a small subpopulation of retrogradely labelled neurons in both experiments. This suggests that RIG‐neurons innervate various target organs. This conclusion is in agreement with the observation that RIG‐neurons also exist in other sympathetic ganglia. Data presented suggest that sympathetic ganglion cells can be classified on the basis of non‐uniform innervation patterns formed by axons that use different neurotransmitters.
Interstitial cells of the adult neocortical white matter are the remnant of the early generated subplate neuron population
Authors: Chun Jerold J. M. , Shatz Carla J. 
Published: January 2005

AbstractThe postnatal fate of the first‐generated neurons of the cat cerebral cortex was examined. These neurons can be identified uniquely by 3H‐thymidine exposure during the week preceding the neurogenesis of cortical layer 6. Previous studies in which 3H‐thymidine birthdating at embryonic day 27 (E27) was combined with immunohistochemistry have shown that these neurons are present in large numbers during fetal and early postnatal life within the subplate (future white matter), that they are immunoreactive for the neuron‐specific protein MAP2 and for the putative neurotransmitters GABA, NPY, SRIF, and CCK. Here, the same techniques were used to follow the postnatal location and disappearance of the early generated subplate neuron population.At birth (P0), subplate neurons showing immunoreactivity for GABA, NPY, SRIF, or CCK are present in large numbers and at high density within the white matter throughout the neocortex, and the entire population can be observed as a dense MAP2‐immunoreactive band situated beneath cortical layer 6. Between P0 and P401 (adulthood), the MAP2‐immunostained band disappears so that comparatively few MAP2‐immunoreactive neurons remain within the white matter. There is a corresponding decrease in the number and density of neurons stained with antibodies against neurotransmitters. In each instance, these neurons could be double‐labeled by the administration of 3H‐thymidine at E27, indicating that they are the remnants of the early generated subplate neuron population. The major period of decrease occurs during the first 4 postnatal weeks, and adult values are attained by 5 months. Within the white matter of the lateral gyrus (visual cortex), the density of immunostained neurons decreases dramatically: MAP2, 82%, SRIF, 81%, and NPY, 96%. While SRIF‐immunoreactive neurons compose a nearly constant percentage of MAP2‐immunoreactive neurons in the white matter between P0 (22%) and P401 (23%), those immunoreactive for NPY decline from 18 to 4%. These changes occur during the same period in which there is less than a twofold increase in white matter area.These observations indicate that the interstitial neurons of the adult neocortical white matter are the oldest neurons of the cerebral cortex since most if not all are derived from the subplate neuron population. In addition, a quantitative analysis suggests that the postnatal decline in subplate neuron density cannot be accounted for solely through dilution by differential growth of the white matter and most likely reflects an absolute decrease in subplate neuron number. Thus, the adult interstitial neurons have survived a postnatal period during which many of their early generated cohorts have disappeared, probably via cell death.
Origin of ascending and spinal pathways from the nucleus tegmenti pedunculopontinus in the rat
Authors: Spann Bryan M. , Grofova Irena 
Published: January 2005

AbstractThe distribution and collaterlization of ascending and descending projections from neurons in the nucleus tegmenti pedunculopontinus (PPN) were studied in the rat by using retrograde transport of HRP, HRP/WGA, and fluorescent dyes. The PPN and its two subdivisions, the subnucleus compactus (PPNc) and subnucleus dissipatus (PPNd), were delineated on sagittal Nisslstained sections by using cytoarchitectural features as guidelines.Large bilateral pressure injections of HRP and/or fluorescent dyes into the cervical cord retrogradely labeled moderate numbers of fusiform and polygonal PPN cells which ranged in size between 65 and 390 μm2. The labeled cells were scattered throughout the PPNd and were somewhat more numerous in the medial half of the subnucleus. The PPNc contained only occasional labeled cells in its ventralmost portion.Following single unilateral HRP/WGA injections in the striatum, globus pallidus, entopeduncular nucleus, subthalamus, or the substantia nigra, the distribution of the labeled cells was similar to that of the spinal cord‐projecting PPN neurons. Multiple HRP injections were then made bilaterally in the substantia nigra and the entopeduncular nucleus and/or subthalamus in order to label the entire population of PPN neurons projecting to the basal ganglia. In this case, not only the PPNd but also the PPNc contained a substantial number of retrogradely labeled cells. The rostrally projecting PPN cells outnumbered 5.4 times those projecting to the spinal cord, and their somata were somewhat larger, ranging between 114 and 472 μm2. While both fusiform and polygonal shapes were encountered, the polygonal cell somata were more numerous.In the double‐labeling experiments, Granular Blue and Diamidino Yellow Dihydrochloride were injected into the cervical cord and the entopeduncular nucleus or subthalamus. In general, these experiments confirmed the extensive overlap of forebrain‐ and spinal cord‐projecting neurons within the PPNd and the quantitative preponderance of ascending neurons. They also demonstrated that these two projection systems originate largely from separate cell populations since the double‐labeled cells always composed less than 5% of the labeled neurons.The results confirm the existence of a direct PPN projection to the spinal cord. This pathway originates mainly in the PPNd and appears to be quantitatively weaker than the PPN projections to the forebrain. The spinal cord‐projecting cells are not spatially segregated from the cells projecting to the basal ganglia, but they represent a separate population of the PPN projection neurons.
Interganglionic dendrites constitute an output pathway from the procerebrum of the sanil Achatina fulica
Authors: Chase Ronald , Tolloczko Barbara 
Published: January 2005

AbstractThe procerebrum is an olfactory processing region that occupies approximately one‐third of the total brain area in pulmonate gastropod molluscs. It has many unusual features, including a development separate from the rest of the brain and the absence of axons belonging to its intrinsic neurons. We have investigated the input and output pathways of the procerebrum in the terrestrial snail Achatina fulica by using hexamminecobalt chloride as a selective label. Both the tentacle nerve and the cerebropedal connective nerve contribute to a fine neural plexus that is distributed throughout the neuropile region of the procerebrum. The fibers from the tentacle nerve are predominantly presynaptic, whereas those from the cerebropedal connective are predominantly postsynaptic. The postsynaptic fibers (dendrites) were traced to two groups of nerve cells (total number, 20–25) near the ventral surface of the ipsilateral pedal ganglion. No evidence was obtained for any other numerically significant output pathway from the procerebrum. Since locomotion is known to be controlled by the pedal ganglion, these results provide an anatomical substrate for the strong influence of olfaction on locomotor behavior in snails. The pathway is unusual in that the dendrites are interganglionic and can be as long as 5 mm.
Viscerotopic representation of the upper alimentary tract in the rat: Sensory ganglia and nuclei of the solitary and spinal trigeminal tracts
Authors: Altschuler Steven M. , Bao Xinman , Bieger Detlef , Hopkins David A. , Miselis Richard R. 
Published: January 2005

AbstractThe aim of this study was to map the viscerotopic representation of the upper alimentary tract in the sensory ganglia of the IXth and Xth cranial nerves and in the subnuclei of the solitary and spinal trigeminal tracts. Therefore, in 172 rats 0.5–65 μl of horseradish peroxidase (HRP), wheat germ agglutinin‐HRP, or cholera toxin‐HRP were injected into the trunks and major branches of the IXth and Xth cranial nerves as well as into the musculature and mucosa of different levels of the upper alimentary and respiratory tracts.The results demonstrate that the sensory ganglia of the IXth and Xth nerves form a fused ganglionic mass with continuous bridges of cells connecting the proximal and distal portions of the ganglionic complex. Ganglionic perikarya were labeled in crude, overlapping topographical patterns after injections of tracers into nerves and different parts of the upper alimentary tract. After injections into the soft palate, pharynx, esophagus, and stomach, anterograde labeling was differentially distributed in distinct subnuclei in the nucleus of the tractus solitarius (NTS). Palatal and pharyngeal injections resulted primarily in labeling of the interstitial and intermediate subnuclei of the NTS and in the paratrigeminal islands (PTI) and spinal trigeminal complex. Esophageal and stomach wall injections resulted in labeling primarily of the subnucleus centralis and subnucleus gelatinosus, respectively.The distribution of upper alimentary tract vagal‐glossopharyngeal afferents in the medulla oblongata has two primary groups of components, i.e., a viscertopic distribution in the NTS involved in ingestive and respiratory reflexes and a distribution coextensive with fluoride‐resistant acid‐phosphatase‐positive regions of the PTI and spinal trigeminal nucleus presumably involved in visceral reflexes mediated by nociceptive or chemosensitive C fibers.
Junction between parent and daughter axons in regenerating myelinated nerve: Properties of structure and rapid axonal transport
Authors: Chan H. , Smith R. S. , Snyder R. E. 
Published: January 2005

AbstractThe primary aim of this work was to investigate the properties of rapid axonal transport in regenerating myelinated axons in the sciatic nerve of Xenopus laevis, with particular attention to events at the junction between the proximal, intact axon (the “parent”) and the distal, newly formed axon (the “daughter”). Morphological studies indicated that all myelinated axons initiated regeneration and that at least 80% of these axons regenerated at a rate of 1 mm/day or greater (20°C). The ultrastructure of the junctional region was examined at regeneration times between 3 days and 20 weeks. The main qualitative change in the junctional axoplasm over this period was in its content of particulate organelles. At times up to 2 weeks regeneration, the junction contained abnormal numbers of 50 nm diameter vesicles and 10 nm granules. Between 2 and 5 weeks the junction showed in addition a peripheral rim of large membrane‐bounded organelles around a central core of microtubules and neurofilaments. At longer times the numbers of large membrane‐bounded organelles diminished and all junctions contained prominent accumulations of 10 nm granules. The rate of rapid axonal transport of protein was similar in parent and daughter axons. Compared to the parent axons, a 2–5 times greater amount of protein was deposited to a stationary phase in daughter axons. Specimens of nerve that were subjected to mechanical stress during the removal of the perineurium showed a large accumulation of rapidly transported protein in the region of the crush at regeneration times up to 40 days; some of the accumulated protein was subsequently transported retrogradely. Video microscopy of isolated axons supplied evidence that the transport deficit in mechanically stressed nerve was a partial block of anterograde vesicle transport, plus a reversal of anterograde transport, at the junction of parent with daughter axons. No structural changes were detected in mechanically stressed nerve. The results show that the junction between parent and daughter myelinated axons is a region with distinct morphology at which the dynamics of anterograde axonal transport may change dramatically.
Endocytosis and autophagy in dying neurons: An ultrastructural study in chick embryos
Authors: Hornung J. P. , Koppel H. , Clarke P. G. H. 
Published: January 2005

AbstractIn an effort to understand naturally occurring neuronal death in the developing isthmo‐optic nucleus, we have accentuated one of its most probably causes, failure to receive adequate trophic maintenance from the axonal terminal zone in the retina, and have studied the dying neurons ultrastructurally. Retrograde trophic maintenance was blocked by means of intraocularly injected colchicine, which caused all the isthmo‐optic neurons to die by just one of the two or more kinds of cell death that they undergo during normal development. The present paper deals with the very prominent cytoplasmic aspects of this kind of cell death, notably the uptake of exogenous horseradish peroxidase and autophagy. There were also nuclear changes, which are dealt with mainly in the accompanying paper (Clarke and Hornung, J. Comp. Neurol. 283: 438–449, '89).Numerous cytoplasmic vacuoles occurred in both soma and dendrites, and they were of three main kinds, of which the smallest (less than 0.5 μm diameter) had unstructured contents, whereas the larger two (1–2 μm and 2–7 μm) were secondary lysosomes (mostly residual bodies).Intravascularly injected horseradish peroxidase labeled all three kinds of vacuole but not the free cytoplasm, indicating that the uptake was by endocytosis rather than by leakage through holes in the membrane, as is confirmed by our failure to detect any such holes. We suspect that the smallest vacuoles are the primary endosomes, that these subsequently fuse with vacuoles of the intermediate kind, and that the largest vacuoles are formed by the fusion of these latter. The purpose of the endocytosis may be to channel the plasma membrane piecemeal into the lysosomes for destruction.
Changes in the nuclei of dying neurons as studied with thymidine autoradiography
Authors: Clarke P. G. H. , Hornung J. P. 
Published: January 2005

AbstractThymidine autoradiography has been used at light and electron microscopic levels to elucidate intracellular events during the death in chick embryos of isthmo‐optic neurons deprived of trophic maintenance from their axonal target organ, the retina. When the intense cytoplasmic vacuolization described in the accompanying paper (Hornung, Koppel, and Clarke, J. Comp. Neurol. 283: 425–437, '89) was beginning, the nuclei also underwent profound changes. They became more electron dense and shrank; their membranes became more sharply defined and convoluted; they sometimes contained pyknotic balls, but apparently only in the early stages of cell death; all lost more than half of their content of DNA, some of which was transferred to the largest kind of cytoplasmic vacuole. This transfer may have involved the budding off of nuclear regions containing pyknotic balls. The cells continued to survive for a day or 2 after these severe losses of nuclear DNA, sustaining intense endocytic activity. Pronounced unscheduled DNA synthesis occurred in the nuclei, but this was insufficient to replace the lost DNA.