bluuebunny/crossref_metadata_2025_split huggingface dataset:
The organization of certain afferents to the hippocampus and dentate gyrus in normal and reeler mice
Authors: Stanfield Brent B. , Caviness Verne S. , Cowan W. Maxwell 
Published: December 2004

AbstractThe organization of certain of the major afferents to the hippocampus and dentate gyrus has been studied in normal and reeler mutant mice using the autoradiographic and the anterograde degeneration methods. The distribution of the hippocampal and dentate afferents which arise in the medial and lateral parts of the entorhinal cortex and the hippocampus of both sides, has been found to be generally similar to that previously described in the rat, but there are a few minor differences that are discussed in the text.Despite the marked ectopia of many of the neurons in the hippocampal for mation in the reeler mouse, the Principal afferents to the hippocampus and the dentate gyrus maintain many of the features seen in normal mice. In particular, they maintain a normal radial sequence and a characteristic laminated and complementary arrangement. However, there are a number of significant differences in their distribution; for example in the reeler mouse, the entorhinal afferents occupy the entire extent of the stratum moleculare of the dentate gyrus, whereas in normal mice they are restricted to the outer four‐fifths of this layer. Furthermore, in the mutant the commissural and associational afferents to the dentate gyrus do not occupy the inner one‐fifth of the molecular layer (as they do in normal animals) but rather are spread throughout the zone containing granule cells, which includes both the poorly‐defined stratum granulosum and most of the hilar region of the dentate gyrus. Some of the developmental and functional implications of these and other abnormalities in the organization of the afferents to the hippocampus and dentate gyrus are discussed.
The effects of eliminating impulse activity on the development of the retinotectal projection in salamanders
Authors: Harris William A. 
Published: December 2004

AbstractThe California newt Taricha torosa manufactures tetrodotoxin, a blocker of voltage‐sensitive sodium channels and therefore of action potentials. The newt's own nervous system is insensitive to this toxin. Grafting an embryonic eye to the newt from a tetrodotoxin‐sensitive species, the Mexican axolotl, blocks action potentials in the retinal ganglion cells of the transplanted eye. Neuroanatomical and electrophysical techniques demonstrate that while such ganglion cells are incapable of firing impulses, they develop normally, grow axons to the host tectum, terminate in the appropriate neuropil layers, form synapses, and project to the tectum retinotopically. Furthermore, they develop these apparently normal projections even in competition with electrically active axons from a host eye.
The distribution of cholecystokinin‐like immunoreactive neurons and nerve terminals in the retrohippocampal region in the rat and guinea pig
Authors: Köhler Christer , Chan‐Palay Victoria 
Published: December 2004

AbstractThe distribution of cholecystokinin (CCK)‐like (CCK‐L) immunoreactive cells and nerve terminals was studied in the brains from rats and guinea pigs by using antibodies to the octapeptide cholecystokinin (CCK‐8). Analysis of serial horizontal and sagittal sections through the retrohippocampal region in colcicine‐pretreated rats revealed a relatively large number of CCK‐L immunoreactive cells in the pre‐ and parasubiculum, subiculum, and the medial and lateral entorhinal area (EA) at all dorsal to ventral levels of the region. In the EA, the CCK‐positive cells were scattered in all layers without any clear pattern. Analysis of CCK‐positive cells in the retrohippocampal region showed that these cells form a morphologically heterogeneous group. The types of CCK‐L immunoreactive cells ranged from small(∼10 μm) round, ovoid, or fusiform to large (∼30μm) multipolar and pyramidal. CCK‐L immunoreactive nerve fibers and preterminal processes were unevenly distributed in the retrohippocampal region. The densest innervation was found in the parasubiculum, subiculum, and the ventrolateral entorhinal area. Only a few scattered fibers were detected in the molecular layer of these structures and the outer layers of the presubiculum. Within the EA the CCK innervation indicated a heterogeneous laminar distribution that was densest in layers II and IV of the medial and lateral EA and diffuse in layers I and III. In layer II the immunoreactive nerve terminals encircled the payramidal cell bodies, while in layers IV to VI and the most ventral part of lateral entorhinal area (LEA) and the transitional area between LEA and piriform cortex the CCK processes were distributed in a netlike fashion without clear relation to the cytoarchitectural characteristics of the area.
The medial accessory nucleus of bechterew: A cell group within the anatomical limits of the rostral oculomotor complex receives a direct prefrontal projection in the monkey
Authors: Leichnetz George R. 
Published: December 2004

AbstractThe medial accessory nucleus of Bechterew, a vertically oriented cell group in the rostral lateral oculomotor nucleus (OMN), contiguous dorsally with the nucleus of DarKschewitsch (ND) and ventrally with the parvocellular red nucleus, is separated from the interstitial nucleus of Cajal (IC) by a small paraoculomotor fascicle (POF) that forms the anatomical limits of the OMN. Horseradish peroxidase (HRP) gel implants in the prearcuate frontal cortex dorsal to the caudal third of the principal sulcus in the monkey resulted in an anterogradely labeled bilateral projection to this paraoculomotor cell group. The functional role of this largely overlooked nucleus is yet to be determined. However, the failure to retrogradely label following HRP injections involving both the extraocular muscles and ciliary ganglion suggests that it cannot be classified as belonging to either the somatic or the visceral cell column at the present time. We suggest that, like IC and ND, it probably contributes to the POF of the medial longitudinal fasciculus and may be involved in internuclear connections. There is little doubt that it has been involved inadvertently in studies of oculomotor connections.
Brainstem afferents to the thalamus in a lizard, Varanus exanthematicus
Authors: Hoogland Piet V. 
Published: December 2004

AbstractHRP was injected into various thalamic nuclei in order to investigate the brainstem projections to the thalamus in the lizard Varanus exanthematicus. Nucleus dorsomedialis receives afferents from the septal area, nucleus entopeduncularis anterior, nucleus periventricularis hypothalami, area triangularis, nucleus raphes superior, nucleus reticularis inferior, and locus coeruleus. Nucleus dorsolateralis receives afferents from septal area, nucleus dorsomedialis, nucleus entopeduncularis anterior, nucleus periventricularis hypothalami, and the torus semicircularis. Nucleus rotundus receives an input from the tectum mesencephali, the pretectal area, and from the mesencephalic reticular fromation. Nucleus intermedius dorsalis receives afferents from the dorsal column nuclei and nucleus periventricularis hypothalami. Nucleus ventrolateralis receives afferents from the dorsal column nuclei, the trigeminal complex, locus coeruleus, and the reticular formation. Nucleus ventromedialis also receives afferents from the trigeminal complex and the reticular formation. Afferents to the habenula have been demonstrated from the septal area, nucleus entopeduncularies anterior triangular area, nucleus periventricularis hypothalami, nucleus interpeduncularis, nucleus raphes superior, locus coeruleus, nucleus isthmi, nucleus dorsalis motorius nervi vagi, and the mesenscephalic tegmentum. The laminar part of the torus semicircularis projects to nucleus medialis.
Afferent neurons in the hypoglossal nerve of the zebra finch (Poephila guttata): Localization with horseradish peroxidase
Authors: Bottjer Sarah W. , Arnold Arthur P. 
Published: December 2004

AbstractHypoglossal efferent fibers are known to innervate the vocal organ (syrinx) in songbirds. In order to determine the existence of afferent fibers from the syrinx in the zebra finch, horseradish peroxidase (HRP) was applied to the cut peripheral branch of the hypoglossal nerve that innervates the left side of the syrinx. Cell bodies in the ganglion of the left vagus nerve were labeled, but no transganglionic (anterograde) transport into the CNS was observed at transport intervals of 1 to 5 days. (In comparision, applying HRP to the cut descending branch of the vagus produced labeled cell bodies in the vagal ganglion as well as heavy anterograde label extending into the solitary nucleus.) Injection of HRP conjugated to wheat germ agglutinin into the intrinsic syringeal muscles also labeled cell bodies in the vagal ganglion, and again no transganglionic label was observed. Application of HRP more proximally to the cut hypoglossal trunk resulted in the appearance of labeled cell bodies in the vagal ganglion as well as anterograde label extending from the decending trigeminal tract to the principal sensory nucleus of V. These results indicate that hypoglossal afferents have cell bodies in the vagal ganglion, enter the medulla dorsally with vagal fibers, and terminate in the trigeminal complex. The identification of these afferent fibers raises the important question of their role in vocal learning.
A laminar analysis of the number of neurons, glia, and synapses in the visual cortex (area 17) of adult macaque monkeys
Authors: O'Kusky John , Colonnier Marc 
Published: December 2004

AbstractThe number of neurons, glia, and synapses in the visual cortex of adult macaque monkeys has been estimated by stereological methods. The data is presented separately for 13 sublaminae. For the total cortical thickness, the average numerical density of neurons is approxiametly 120,000 per mm3 of tissue. This density increases and decreases in the different sublaminae in the direction that one would expect from the classical descriptions of Nissl‐stained material (e.g., 137,000/mm3 in IVCα; 211,000/mm3 in IVCβ). There are about 200,000 neurons under 1 mm2 of cortical surface: 28% are in layers I‐III, 45% are in layer IV, and 27% are in layers V and VI. The total number in area 17 of one hemisphere is close to 160,000,000. For the total cortical thickness the numerical density of synapses is 276,000,000 per mm3 of tissue. Laminae with higher neuronal densities tend to have higher synaptic densities but the correlation is not perfectly concordant. Moreover, the changes in synaptic densities are not as great as those in neurol densities so that laminae with higher neuronal densities have a lower synapse to neuron ratio and laminae with lower neuronal densities have a higher synapse to neuron ratio. For the total cortical thickness this ratio is 2,300 synapses per neuron (1,400 in layer IVCβ and 2,800 in layers II and III). There are 478 million synapses under 1 mm2 of cortical surface: 40% are in layers I–III, 35% are in layer IV, and 25% are in layers V and VI. The numerical densities of astrocytes, oligodendrocytes, and microcytes are 38,000, 17,000, and 4,000 per mm3, respectively. The overall glia/neuron ratio is 0.49.
Postnatal changes in the number of neurons and synapses in the visual cortex (area 17) of the macaque monkey: A stereological analysis in normal and monocularly deprived animals
Authors: O'Kusky John , Colonnier Marc 
Published: December 2004

AbstractThe surface area of the striate cortex and the thickness of its laminae were measured in a series of newborn, 3‐month, 6‐month, and adult macaque monkeys. The numerical densities (Nv) of neurons and synapses were measured in individual laminae. The total numbers of neurons and synapses in the striate cortex of one hemisphere were derived from these measures. Normal monkeys were compared at 3 months and 6 months of age to animals having been reared from birth with a monocular eyelid suture. No significant differences were observed between normal and monocularly deprived monkeys. The perceptual deficits and physiological abnormalities that have been reported in monocularly deprived monkeys do not appear to result from a reduction in the amount of neural circuitry in the striate cortex. The combined data from these groups, however, demonstrated several developmental changes. Cortical thickness increased from birth to 6 months and diminished to near‐newborn values in the adult. The 6‐month cortex was 19% thicker than that of adult. This overshoot was greatest in layers II and III, which were 43% thicker at 6 months. Cortical surface area demonstrated a similar trend, being 23% greater at 6 months, but the differences were not statistically significant. The Nv of neurons decreased from birth to 6 months and increased to near‐newborn values in the adult. The 6‐month Nv was 30% less than that of adults and the greatest changes were seen in layers II and III where the Nv was 38% less than adult values. The total number of neurons in the striate cortex of one hemisphere was 16% less in adults than in newborn animals, but statistically significant neuron losses were limited to layers I, II, IVCα, V, and VI. The Nv of synapses increased from birth to 6 months and diminished to near‐newborn values in the adult. The 6‐month overshoot was 34% for the total cortex and 41% for layers I–III. The total numbers of synapses in the striate cortex was 95% greater at 6 months than in the adult. In layers I–III the synapses were 130–155% more numerous at 6 months. These data demonstrate an increase in neuronal connectivity in the striate cortex from birth to 6 months, especially in layers I–III, and a subsequent decrease in the adult.
The fine structure of the perigeniculate nucleus in the cat
Authors: Ide Linda S. 
Published: December 2004

AbstractThe fine structure of the cat's perigeniculate nucleus has been analyzed and compared to that of dorsal thalamic relay nuclei. Golgi preparations and electron micrographs of perigeniculate cells commonly show somatic spines. The most common presynaptic elements for these spines and for the adjacent perikaryal surfaces are relatively large axon terminals containing round synaptic vesicles and making multiple asymmetric contacts. These “RLD” terminals (so termed for their round vesicles, large average size of the terminals, and dark mitochondria) are also presynaptic to dendritic spines and shafts of proximal and secondary dendrites. Comparisons with adjacent parts of the dorsal lateral geniculate nucleus show that these RLD terminals are cytologically distinct from retinogeniculate terminals and that small numbers of RLD terminals also occur in the geniculate A laminae. Three other major classes of perigeniculate synaptic terminals, resemble major classes of terminals in the dorsal lateral geniculate nucleus. These include two types of terminal with flat or ovoid synaptic vesicles and dark mitochondria, “FD1” and “FD2” terminals, and a class of small terminal with densely clustered round vesicles and dark mitochondria, “RSD” terminals. RSD terminals, which resemble corticogeniculate axon terminals, represent the only class of perigeniculate terminal that does not contact perikarya. FD2 terminals resemble lateral geniculate presynaptic dendrites and participate in serial and triadic synaptic contacts, being both pre‐ and postsynaptic; however, in contrast to the arrangement characteristic of thalamic relay nuclei, these contacts do not occur within synaptic glomeruli. A fifth major class of perigeniculate presynaptic terminal has large flat or polymorphic synaptic vesicles and pale mitochondria. These “FP” terminals are seen infrequently in the lateral geniculate A laminae. Similarities between perigeniculate and lateral geniculate fine structure may relate in part to common sources of afferent input to the two nuclei.
Periterminal synaptology of dorsal root glomerular terminals in the substantia gelatinosa of the spinal cord in the rhesus monkey
Authors: Knyigar‐Csillik E. , Csillik B. , Rakic Pasko 
Published: December 2004

AbstractThe synaptic glomerular complexes surrounding dorsal root terminals in the substantia gelatinosa were reconstructed from six sets of 50–140 gapless ultrathin serial sections prepared in the transverse plane of the spinal cord in adult rhesus monkeys. All three types of glomeruler terminals described in the preceding paper (Knyihar‐Csillik et al., 1982) were identified: (1) DSA (endings of superificial collaterals); (2) LDCV (endings of marginal collaterals); and (3) RSV (endings of deep collaterals). Each type of terminal forms a glomerular complex which invariably includes presynaptic dendrites which are intercalated between primary terminals and the postsynaptic (conventional) dendrite. Since the latter also receives direct input from the primary sensory terminal the synaptic organization assumes triadic arrangements, suggesting that primary afferent impulses my be subjected to a postsynaptic modulation through inhibitory action of presynaptic dendrites.In glomeruli with DSA as the central element, several triadic systems are usually interrelated, possibly as a structural basis for prolonged retardation of impulses. Adjacent glomeruli, containing DSA and LDCV terminals, are coupled together by a series of triadic systems fed by DSA terminals enabling association between superficial and marginal collaterals. RSV terminals are presynaptic to somata and dendrites of substantia gelatinosa cells that presumably exert inhibition upon terminals of all three kinds of primary sensory collaterals. In addition RSV terminals are postsynaptic to numerous F boutons which presumably derive mainly from axons of substantia gelatinosa cells; similar F boutons impinge upon presynaptic and other dendrites surrounding DSA terminals. The Complicated but orderly synaptic architecture of these three types of primary afferents may be regarded as a structural basis for first‐order analysis and modulation of the nociceptive information within the primate central nervous system.
The organization of monoamine‐containing neurons in the brain of the salamander, Necturus maculosus
Authors: Dubé Lorraine , Parent André 
Published: December 2004

AbstractThe organization of monoamine (MA)‐containing neuronal systems in the brain of the salamander (Necturus maculosus) was studied by means of paraformaldehyde and glyoxylic acid histofluorescence methods. The MA neurons were further characterized morphologically andhistochemically in material prepared for the demonstration of cholinesterase activity.In the brain ofNecturus, the most caudally located catecholamine (CA)‐containing cells occur in the nucleus of the solitary tract. A large population of serotonin (5‐HT)‐containing cells is also found along the entire rostrocaudal extent of the raphe region of the brainstem. At isthmal levels, a few scattered CA cells lie dorsolaterally in the so‐called acousticolateral area. These neurons can be seen to send axonal projections to the spinal cord and the cerebellum, but not to the telencephalon, and thus can not be considered as fully homologous to the locus coeruleus of reptiles, birds, and mammals. Within the midbrain, some cells displaying a strong CA fluorescence and staining intensely for cholinesterases are present near the oculomotor nerve root fibers. They give rise to a long ascending fiber system arborizing in the striatum, and this system appears homologous to the mesostriatal CA pathway of amniotic vertebrates. At diencephalic levels a multitude of CSF‐contacting cells of both CA and 5‐HT types occurs. They abound particularly in the ventral thalamus, along the infudibular recess, in the dorsal infundibular nucleus, and in the ventral thalamus. As a whole, this population of CSF‐contacting MA cells is considered homologous to the paraventricular organ present in all nonmammalian vertebrates. Some CA cells also occur along the preoptic recess, around the hippocampal commissure, and even within the caudalmost aspect of the medial pallium. The presence of CA cell bodies among telencephalic cell groups has not been demonstrated in other vertebrates. The heaviest CA innervation in the telencephalon is found in the neuropil of the corpus striatum and in the “prominentia ventralis” (nucleus accumbens septi), both of which also stain significantly for cholinesterases. Finally, numerous CA cells are scattered throughout the magnocellular, molecular, and granular cell layers of the olfactory bulb. These cells provide a strong CA innervation to the glomerular layer of the bulb which also exhibits a high cholinesterase activity seemingly derived from the processes ofperiglomerular cells. Thus, the pattern of organization of MA systems in Necturus appears unique in many aspects, but it also displays striking similarities to the arrangement of brain MA neurons disclosed in other vertebrates.
The cytoarchitecture of the dorsal cochlear nucleus in the 3‐month‐ and 26‐month‐old C57BL/6 mouse: A golgi impregnation study
Authors: Browner Robert H. , Baruch Alice 
Published: December 2004

AbstractThe cytoarchitecture of the dorsal cochlear nucleus (DCN) was compared in 3‐ and 26‐month‐old C57BL/6 mice. The effects of genetically controlled progressive hearing loss present in the CNS in this mouse strain were analyzed with Nissl‐stained and Golgi‐impregnated material. The DCN was divided into the superficial molecular, an intermediate fusiform‐granule, and the deep polymorphic layers. The molecular layer (ML) consisted of many fibers and a few small ovoid to spherical, fusiform, and granule cells. The fusiform‐granule layer (FL) contained large fusiform and many granule cells. Most FL fusiform cells were oriented with their long axes perpendicular to the DCN surface and were present as small aggregations or individually. Cartwheel cells were adjacent to the FL fusiform cells. The deep polymorphic layer (PL) contained spherical, fusiform, granule, and multipolar neurons. The granule cells formed a dorsal cap of the DCN. From this cap, sheets of granule cells separated the DCN from the posterior ventral cochlear nucleus (PVCN) and from the brainstem.The internal organization, neuronal location, orientation, and morphology were similar in both age groups. The granule cells had four to five primary dendrites, varicosities, and few to no dendritic appendages. The FL fusiform cells displayed different dendritic morphology in the two ages. One or two elaborate primary ML apical dendrites in the 3‐month‐old mice were covered with spikelike dendritic spines. The basal one or two PL dendrites were less elaborate and had few dendrite spines. In contrast, FL fusiform neurons in 26‐month‐old mice had regular dendritic varicosities and fewer spines which were short and stumpy. Basal dendrites had varicosities and interruptions. Cartwheel neurons in 3‐month‐old mice had elaborate ML dendritic trees covered with dendritic spines. In 26‐month‐old mice the dendrites had many varicosities and fewer short blunted dendritic spines. Large multipolar neurons in older mice had thinner dendrities with more varicosities than were in the 3‐mcnth group. In both age groups multipolar cells had few dendritic spines limited distally. Small and large spherical cells had two to five primary dendrites with varicosities, little higher‐order branching, and spines. Fusiform cells had one or two primary dendrites, little secondary branching, and few to no spines. Minor degenerative changes were noted in spherical and fusiform cells in the two age groups. These included dendritic varicosities, interruptions, and some irregularities of somata surface. Degenerative changes present in the cochlea had significant effects on a limited population of DCN neurons. Finally, the neusronal morphology and architecture of the DCN in C57BL/6 mouse is similar to other mammalian species.