bluuebunny/crossref_metadata_2025_split huggingface dataset:
Number of neurons in individual laminae of areas 3B, 4γ, and 6aα of the cat cerebral cortex: A comparison with major visual areas
Authors: Beaulieu Clermont , Colonnier Marc 
Published: January 2005

AbstractThe number of neurons per mm3 of tissue (number per volume) and the number under 1 mm2 of cortical surface (number per column) have been estimated for each lamina of seven cytoarchitectural areas of the cat cortex by using a method of size frequency distribution. The areas studied consisted of four visual areas (the binocular and monocular portions of area 17: 17B and 17M; area 18; and the posteromedial lateral suprasylvian area: PMLS), a somatosensory area (3B), and two motor areas (4γ and 6aα).For both series of measurements, significant differences could be demonstrated among the seven areas studied (one‐way ANOVA; P < .001). The number of neurons per volume in the binocular and monocular regions of area 17 (≈︁ 49,000/mm3) is 85% greater than that of each of the other regions (≈︁ 27,000) with a P < .01 on an a posteriori Tukey test, but there are no significant differences between the latter areas. The number of neurons per column is greater in the binocular portion of area 17 (78,000 under 1 mm2 of cortical surface) than in any other area (P < .01). Other sensory areas (17M, 18, PMLS, and 3B) have fewer neurons per column (P < .01) and the numbers do not vary significantly between these regions (range from 56,100 to 61,900). Areas 4γ and 6aα have still fewer neurons ( ≈︁ 44,000; P < .01, except P < .05 when compared to PMLS). Thus, the seven areas studied fall under three different categories. Motor areas have the smallest number of neurons per column, sensory areas have more, and the greatest number is found in the binocular region of area 17. It appears that these differences are principally (but not exclusively) due to variations in the number of neurons in layer IV: These variations are largely responsible for the differences that we have found between the binocular portion of area 17 and other sensory areas as well as between the binocular portion of area 17 and other sensory areas as well as between the latter and motor areas. We thus cannot confirm the view of Rockel et al. (Brain 103:221–244, ';80) that there is a basic uniformity of the number of neurons per unit of cortical surface in different cortical areas of the cat.
Comparative distribution of three opioid systems in the lower brainstem of the monkey (Macaca fuscata)
Authors: Ibuki Takae , Okamura Hitoshi , Miyazaki Masao , Yanaihara Noboru , Zimmerman Earl A. , Ibata Yasuhiko 
Published: January 2005

AbstractThe regional distribution of the three opioid peptide neuronal systems‐proopiomelanocortin (POMC), proenkephalin A, and proenkephalin B‐was investigated in the lower brainstem of Japanese monkeys (Macaca fuscata) by immunocytochemical techniques. Antiserum to β‐endorphin/β‐lipotropin, [Met]‐enkephalin‐Arg6‐Gly7‐Leu8, and human leumorphin were used to identify the POMC and the proenkephalin A and B systems, respectively. POMC‐related immunoreactive material was not found in the neuronal perikarya in the lower brainstem; reactive fibers and apparent terminals were distributed in the substantia nigra, lemniscus lateralis, midbrain central gray, the nucleus raphes, nucleus parabrachialis lateralis, ventral area of the spinal trigeminal nerve, nucleus tractus solitarii, and in the reticular formation throughout the lower brainstem. Proenkephalin A‐related immunoreactive neuronal perikarya were detected in the central gray, reticular formation, nucleus raphes, trapezoid body, nucleus parabrachialis lateralis and medialis, nucleus spinalis nervi trigemini, nucleus dorsalis nervi vagi, and in the nucleus tractus solitarii. Densely packed immunoreactive fibers were widely distributed in the substantia nigra, nucleus interpeduncularis, nucleus raphes, superior colliculus, periaqueductal central gray, nucleus parabrachialis lateralis and medialis, locus coeruleus, trapezoid body, nuclei cochleares, nucleus spinalis nervi trigemini, tractus spinalis nervi trigemini, nucleus tractus solitarii, nucleus dorsalis nervi vagi, nucleus gracilis, nucleus cuneatus, nucleus cuneatus accessorius, and in the reticular formation throughout the lower brainstem. Neuronal perikarya containing immunoreactive material related to proenkephalin B were found in the periaqueductal central gray, nucleus parabrachialis lateralis and medialis, nucleus tractus solitarii, and nucleus spinalis nervi trigemini. In addition, immunoreactive fibers were detected in the ventral tegmental area, substantia nigra, nucleus parabrachialis lateralis and medialis, nucleus vestibularis lateralis and medialis, and in some areas of the reticular formation. These anatomical findings demonstrate that these three opioid peptide neuronal systems are widely but uniquely distributed in the lower brainstem of the monkey.
Sensory pathways and motoneurons of the proboscis reflex in the suboesophageal ganglion of the honey bee
Authors: Rehder Vincent 
Published: January 2005

AbstractA morphological description is given for the motoneurons underlying the proboscis extension reflex in the honey bee (Apis mellifera). Sensory neurons from the mandibles and labium were examined and their projection areas were related to those of the motoneurons. Motoneurons are located in the ventral part of the suboesophageal ganglion, have their somata in the hemiganglion ipsilateral to the filled nerve, and send prominent branches through identified ventral commissures into the contralateral hemiganglion. Motoneurons to the same muscle have parallel‐running projections into the contralateral hemiganglion, often parallel‐running neurites, and show vast areas of dendritic overlap. Arborizations of motoneurons are not restricted to their neuromere of origin but invade adjacent neuromeres, resulting in regions of dendritic overlap of motoneurons to different muscles. Sensory fibers from the mouthparts terminate in medio‐ and mediolateral parts of the suboesophageal ganglion, where their arborizations overlap with projections from motoneurons. A few sensory fibers descend in ventral parts of the cervical connective. Although sensory neurons from the mandible are restricted to the ipsilateral hemiganglion, those of the labium also show contralateral branches. These observations are discussed in the context of the suboesophageal ganglion as a ganglion composed of the embryonic fusion of three single neuromeres.
Postembryonic development of serotoninlike immunoreactivity in the central nervous system of the snail, lymnaea stagnalis
Authors: Croll Roger P. , Chiasson Bernard J. 
Published: January 2005

AbstractPosthatching growth in the pond snail Lymnaea stagnalis involves approximately a 20‐fold increase in the linear dimensions of the ganglia composing the central nervous system. Developmental change within the population of neurons exhibiting serotoninlike immunoreactivity (SLIR) was examined in order to explain this growth in cellular terms. The study indicates that at least two factors contribute to the growth of the nervous system. First, SLIR cells approximately double in number from the 200–250 cells in hatchlings to the complement found in animals approaching sexual maturity. Much of this increase in cell number occurred within identifiable discrete clusters of neurons with different clusters adding cells at different rates and at different times. The number of SLIR cells also increased in more diffuse populations, particularly along the medial aspects of the paired pedal and the right parietal ganglion. No identified cells were added postembryonically. In addition to the increases in neuron numbers, posthatching development in Lymnaea also involves the growth of individual cells. All cells examined showed continuous somatic growth during posthatching development, but different identified cells and different cell clusters were characterized by different rates of relative growth. Together, the results highlight the complexity of postembryonic development in the snail by indicating the temporal and spatial specificity for both cell addition and cell growth within the nervous system.
Forms and measures of adult and developing human corpus callosum: Is there sexual dimorphism?
Authors: Clarke Stephanie , Kraftsik Rudolf , van der Loos Hendrik , Innocenti Giorgio M. 
Published: January 2005

AbstractThe sexual dimorphism of the human corpus callosum (CC) is currently controversial, possibly because of difficulties in morphometric analysis. We have reinvestigated the issue by using morphometric techniques specially designed to yield objective measurements of CC size and shape. The development of the CC was studied with similar techniques in order to investigate whether its final shape and size might be influenced by axonal elimination, as could be expected from previous animal studies.We have measured the CCs of 32 men and 26 women; 27 male and 19 female CCs were from brain tissue, the others were from magnetic resonance imaging graphs. Women tended to have (1) a smaller cross‐sectional callosal area (CCA); (2) a larger fraction of CCA in the posterior fifth of the CC; (3) more slender CCs; and (4) more bulbous splenia. These differences could not be detected by simple inspection but were demonstrated by measurement and statistical analysis. However, CCA was correlated with the other sexually dimorphic parameters, and the sex‐related differences in the latter became nonsignificant when variations in CCA were factored out or when male and female populations with similar CCA were compared.In addition, we analyzed CCs of 16 male and 16 female fetuses and of 13 male and 15 female infants and children. This sample ranged in age between 20 weeks of gestation and 14 years but covered in detail the period up to 14 months after birth. CCA increased throughout the latter period but decreased slightly between about 33 weeks of gestation and the beginning of the second postnatal mouth. This decrease coincided with thinning of the CC and a marked increase in bulbosity of the splenium. No sexual dimorphism could be demonstrated until the beginning of the postnatal period. In the age group between birth (at term) and the 14th month, CCA was, as in the adult, larger in males. Unlike in the adults, the CC was longer in males and the bulbosity index was the same in the two sexes. Axonal elimination may play a role in the perinatal pause in CCA growth and in the concomitant changes in callosal shape.
Efferent projections from limbic cortex of the temporal pole to the magnocellular medial dorsal nucleus in the rhesus monkey
Authors: Gower E. C. 
Published: January 2005

AbstractThe efferent projection from the rostral cortices of the temporal lobe to the magnocellular division of the medial dorsal nucleus (MDmc) was studied in the rhesus monkey (Macaca mulatta). The temporal pole region contains four architectonically defined cortical divisions. Medially, the allocortex of the temporal limb of the pyriform cortex is annexed to the temporal lobe neocortices at the limen insulae. Two transitional neocortices, the periallocortical and proisocortical divisions, are situated subjacent to the pyriform area. They make up the largest part of the temporal tip and separate the pyriform cortex from the architecturally more progressive isocortical divisions of the pole found laterally at the rostral ends of the superior and inferior temporal gyri. Neuroanatomical tracers were injected into each of the major divisions of the temporal pole cortex, and the injection site locations were characterized cytoarchitectonically as well as geographically. Injections of tritiated amino acids into pyriform allocortex or into the transitional neocortical fields revealed an efferent projection to the magnocellular medial dorsal nucleus. The terminal field was characterized by a mosaic type of organization and contained discrete zones of axonal termination in which bursts of coarse label surrounded neuronal perikarya and their proximal dendrites. A similar projection was also observed when horseradish peroxidase was injected into the transitional cortices. However, perikarya participating in the terminal clusters were not retrogradely labeled. Intracortical injections restricted to lateral polar isocortex did not result in either anterograde or retrograde transport of label to MDmc. These findings demonstrate a nonreciprocal, corticofugal pathway to MDmc that originates in the phylogenetically older districts of the temporal pole. The conduction of limbic sensory information directly from temporal neocortex to the medial thalamus may play a fundamental role in human and primate memory.
Laminar and segregated distribution of immunoreactivities for some neuropeptides and adenosine deaminase in the superior colliculus of the rat
Authors: Miguel‐Hidalgo Jose‐Javier , Senba Emiko , Matsutani Shinji , Takatsuji Koichi , Tohyama Masaya , Fukui Hiroyuki 
Published: January 2005

AbstractThe distribution and morphology of adenosine deaminase, substance P, leucine‐enkephalin, corticotropin‐releasing factor, and calcitonin gene‐related peptidelike immunoreactive cells and fibers throughout the superior colliculus of the rat were examined by means of the unlabelled‐antibody peroxidase‐antiperoxidase method. Adenosine deaminase immunoreactive cells were found in the stratum opticum and lower stratum griseum superficiale; substance P immunoreactive cells were localized to the upper stratum griseum superficiale, and calcitonin gene‐related peptide immunolabelled neurons were situated in deeper strata. Substance P, leucine‐enkephalin, and calcitonin gene‐related peptide immunoreactive fibers were distributed similarly in their lamination and in their patchlike organization. Corticotropin‐releasing factor immunoreactive fibers were observed evenly throughout all the strata and were fewer in the stratum griseum superficiale.These findings suggest that, as in afferent modules and segregated efferents of the mammalian superior colliculus, the cells and fibers containing neuroactive substances and neuroactive substance‐related enzymes also show a segregated and laminar distribution.
Endbulbs of held and spherical bushy cells in cats: Morphological correlates with physiological properties
Authors: Sento Seishiro , Ryugo David K. 
Published: January 2005

AbstractSingle auditory nerve fibers of type I spiral ganglion cells in cats were electrophysiologically characterized by recording with micropipettes inserted into the axon and then labeled by intracellular injections of horseradish peroxidase (HRP) through the same pipettes. This method for staining and studying single neurons allowed us to describe structure‐function relationships for labeled endbulbs of Held and the somata of their postsynaptic spherical bushy cells. The silhouette areas of terminal endbulbs and the corresponding somata of spherical bushy cells were determined by planimetry from drawings made with a light microscope and drawing tube. On the presynaptic side, endbulb area is related to fiber characteristic frequency (CF, the frequency to which a fiber is most sensitive) such that the largest endbulbs arise from fibers having CFs between 1 and 4 kHz; smaller endbulbs can arise from fibers of any CF. Endbulb area is not correlated with fiber spontaneous discharge rate (SR). Dividing the endbulb's silhouette area by its silhouette perimeter, however, yields a “form factor” that is a reliable indicator of fiber SR: Endbulbs from fibers of low‐medium SR (≤18 spikes/second) have form factor values less than 0.52, whereas endbulbs of high SR fibers (>18 spikes/second) have values greater than 0.52. This form factor should therefore be predictive of SR groupings in auditory fibers for which physiological data are not available.On the postsynaptic side, the somata of spherical bushy cells receiving endbulbs from low‐medium SR fibers are on average smaller than those receiving endbulbs from high SR fibers. In contrast, the nuclei of the spherical bushy cells are the same size regardless of presynaptic fiber SR. Some of the effects of low‐medium SR fibers on their postsynaptic targets, when compared to those of high SR fibers, appear to be mimicked by effects of experimentally induced deprivation.
Distribution of neuropeptidelike immunoreactivities in the guinea pig olfactory bulb
Authors: Matsutani Shinji , Senba Emiko , Tohyama Masaya 
Published: January 2005

AbstractThe distribution of neuropeptidelike immunoreactivities in the adult guinea pig olfactory bulb was studied immunohistochemically with antiseraraised against neurotensin (NT), substance P (SP), methionine‐enkephalin‐Arg6‐Gly7‐Leu8 (ENK), somatostatin (SOM), neuropeptide Y (NPY), and cholecystokinin‐8 (CCK).In the main olfactory bulb, NT‐like immunoreactive (NT‐IR) neurons were found among periglomerular cells. In addition, a few periglomerular cells showed ENK‐like immunoreactivity. Granule cells displaying SP‐ or ENK‐like immunoreactivities and short axon cells with SOM‐ or NPY‐like immunoreactivities were observed in the deeper half of the granule cell layer. SOM‐IR short axon cells were also seen in the external plexiform layer. Dense NT‐ or NPY‐IR fibers were distributed in superficial lamina of the granule cell layer, and sparse SP‐ or CCK‐IR fibers were found in the glomerular layer.In the accessory olfactory bulb, some mitral, periglomerular, and granule cells showed NT‐like immunoreactivity. SP‐ or ENK‐IR granule cells were also observed.These results are discussed in relation to laminar organization of the olfactory bulb. The most characteristic features of peptide distribution in guinea pigs, as compared with that of rats in previous studies, were the relative abundance of NT‐IR structures and the lack of SP‐and CCK‐IR juxtaglomerular and tufted cells.
Hormonal control of neuron number in sexually dimorphic spinal nuclei of the rat: I. Testosterone‐regulated death in the dorsolateral nucleus
Authors: Sengelaub D. R. , Arnold A. P. 
Published: January 2005

AbstractAdult male rats have substantially more motoneurons than do females in two motor nuclei in the lumbar spinal cord: the spinal nucleus of the bulbocavernosus (SNB) and the dorsolateral nucleus (DLN). Previous studies of the development of the SNB revealed that the sex difference in SNB motoneuron number is established through a differential motoneuron death which is under the control of androgens. In this study the development of the sexually dimorphic DLN was examined to test the hypothesis that early androgen action also determines the sex difference in DLN motoneuron number by regulating normally occurring motoneuron death. Because SNB motoneurons may migrate from the DLN, quantitative examination of DLN development was necessary in order to understand more completely the cellular mechanisms contributing to the establishment of dimorphic motoneuron number.At 5 days before birth, the number of motoneurons in the DLN is significantly higher than in adulthood in both sexes, and no sex difference is present. There is a decrease in motoneuron numbers prenatally in both sexes, which is consistent with the emigration of presumptive SNB motoneurons. Motoneuron number declines differentially through the first week of postnatal life and by postnatal day 10 motoneuron numbers are in the adult range and the sex difference is fully expressed. Females lose significantly more DLN motoneurons than males through a differential death as revealed by the higher incidence of degenerating cell profiles. Females treated with testosterone propionate have a male‐typical motoneuron loss and incidence of degenerating cells. These results indicate that steroid hormones establish the sex difference in DLN motoneuron number by regulating normally occurring cell death.
Distribution of serotonin in the brain of the mormyrid teleost Gnathonemus petersii
Authors: Meek J. , Joosten H. W. J. 
Published: January 2005

AbstractThe distribution of serotonin‐immunoreactive neurons and fibers was studied in the highly developed brain of the weakly electric fish Gnathonemus petersii with the aid of specific antibodies against serotonin. Serotoninergic cell bodies occur in three regions: the raphe region of the brainstem, the hypothalamus, and the transition zone between the dorsal thalamus and the pretectum. Serotoninergic raphe neurons are clustered in three groups: nucleus raphes superior, intermedius, and inferior. The latter has not been described in other teleosts and thus might be the source of the serotoninergic innervation of specific mormyrid electrosensory brain regions. Most hypothalamic serotoninergic neurons have cerebrospinal‐fluid (CSF)‐contacting processes and thus belong to the paraventricular organ (PVO), which in Gnathonemus is located around a number of small infundibular recesses. The distribution of serotonin in the PVO precisely matches the distribution of dopamine, as described previously. Serotoninergic cells in the thalamopretectal transition zone also have been described in other teleosts, but not in other vertebrate groups, and thus seem to represent a teleostean specialization.Serotoninergic fiber density is especially high in the medial forebrain bundle and surrounding preoptic and hypothalamic regions as well as in several telencephalic and preoptic subependymal plexus. Serotoninergic fibers appear to be almost completely absent in the large and differentiated corpus and valvula cerebelli. Comparison with the literature on teleostean serotoninergic innervation patterns reveals several mormyrid specializations, including the absence of serotonin in large parts of the mormyrid telencephalic lobes, a differentiated innervation pattern of distinct electrosensory and mechanosensory subnuclei of the torus semicircularis, a refined serotoninergic lamination pattern in the midbrain tectum, and a prominent innervation of the electrosensory lateral line lobe, the associated caudal cerebellar lobe, and the electromotor medullary relay nucleus. A distinct innervation of several types of (pre)motor neurons, such as the Mauthner cells and facial motor neurons, has not been reported previously for other teleosts. Consequently, the distribution of serotoninergic fibers as well as neurons in the mormyrid brain is substantially adapted to the high degree of differentiation of its electrosensory and telencephalic brain regions, but serotoninergic innervation is not involved in the circuitry of the most impressive part of the mormyrid brain; i.e., its large corpus and valvula cerebelli.