bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ontogeny and sexual dimorphism of the sonic motor nucleus in the oyster toadfish
Authors: Fine Michael L. , Economos Demetri , Radtke Richard , McClung J. Ross 
Published: May 2005

AbstractMale oyster toadfish, Opsanus tau, produce a courtship boatwhistle call and have a larger sound‐producing organ than females, who do not boatwhistle. We investigated the possibility of sexual dimorphism in ontogeny of the sonic motor nucleus (SMN) of the toadfish. Brain weight increases for life though the increase decelerates with increasing fish weight. Neuron number, ranging from 760 to 2,888 in the SMN, increases rapidly to about 3 years, more slowly to about 8 years, and then levels off. There are no sexual differences in regressions of brain weight and SMN neuron number against fish size or age. Neuronal soma size in the SMN increases from 8 to 35 μm in average diameter and 67 to 916 μm2 in area over a period of at least 7 years. Males have larger neurons than females (P<.01). However, males can be separated by inspection into populations with large and small soma sizes. Neuron size is not different between females and males with small somas. Neurons in males with large somas are larger than neurons in females and neurons in males with, small somas. Such male dimorphism is reminiscent of other behavioral and morphological dimorphisms, which have led to characterization of males into territorial and satellite forms in certain mating systems.
Effects of unequal alternating monocular exposure on the sizes of cells in the cat's lateral geniculate nucleus
Authors: Tieman S. B. , Nickla D. L. , Gross K. , Hickey T. L. , Tumosa N. 
Published: May 2005

AbstractIn unequal alternating monocular exposure, each eye receives normal patterned input, but on alternate days and for unequal periods. This imbalance in stimulation produces a behavioral deficit for the less‐experienced eye and alters the ability of that eye to activate cortical cells. To determine whether unequal alternating exposure also affects the sizes of cells in the lateral geniculate nucleus (LGN), we measured the cross‐sectional areas of geniculate neurons in seven normally reared cats, 14 cats reared with equal alternating exposure, and 17 cats reared with unequal alternating exposure. We found that, in the LGNs of cats reared with unequal alternating monocular exposure, cells in layers that received their input from the less‐experienced eye were smaller than those in layers that received their input from the more‐experienced eye. This effect was restricted to the binocular segments of the nucleus, and the difference in cell size was a function of the imbalanced exposure, rather than the length of exposure per se. In control groups given balanced alternating exposure, cell size was not correlated with the length of daily exposure. In cats reared with unequal exposure, the change in cell size was greater in the nucleus ipsilateral to the less‐experienced eye. Further, the size of the effect was correlated with the size of the imbalance imposed during rearing: Cats reared with a moderate imbalance (8 hours/day vs. 4 hours/day) showed less change in cell size than cats reared with a large imbalance (8 hours/day vs. 1 hour/day). These results are consistent with those of behavorial and physiological studies and strongly suggest (1) that unequal alternating monocular exposure affects the sizes of cells in the LGN by altering the normal competitive balance between the retinogeniculocortical pathways from the left and right eyes, and (2) that the contralateral pathway has some inherent advantage in this competition. We also found a slight shrinkage of cells in the LGNs of cats reared with equal alternating monocular exposure. Since this effect was restricted to the binocular segments of the nucleus, and was not related to the length of exposure given, it was probably caused by the imbalanced binocular competition that occurred during each day's monocular exposure.
Central projections of the lateral line nerves in the shovelnose sturgeon
Authors: New John G. , Northcutt R. Glenn 
Published: May 2005

AbstractPrimary projections of the anterior (ALLN) and posterior (PLLN) lateral line nerves were traced in the shovelnose sturgeon by means of horseradish peroxidase (HRP) histochemistry and silver degeneration. The trunk of the ALLN divides into dorsal and ventral roots as it enters the medulla. Fibers of the dorsal root form ascending and descending branches that terminate within the ipsilateral dorsal octavolateralis nucleus and the dorsal granular component of the lateral eminentia granularis. Fibers of the ventral root of the ALLN, as well as fibers of the PLLN, enter the medulla ventral to the dorsal root of the ALLN where some of the fibers terminate among the dendrites of the magnocellular octaval nucleus. The bulk of the fibers form ascending and descending branches that terminate within the ipsilateral medial octavolateralis nucleus. A portion of the ascending fibers continue more rostrally land terminate in the ipsilateral eminentia granularis and bilaterally in the cerebellar corpus. Some fibers of the descending rami of both the ALLN and PLLN extend beyond the caudal limit of the medial octavolateralis nucleus to terminate in the caudal octavolateralis nucleus. The HRP cases also revealed retrogradely filled large neurons whose axons course peripherally in the lateral line nerve and are likely efferent to the lateral line organs.
Embryonic development of the rat cerebellum. I. Delineation of the cerebellar primordium and early cell movements
Authors: Altman Joseph , Bayer Shirley A. 
Published: May 2005

AbstractShort‐survival and long‐survival thymidine radiograms, and methacrylate‐embedded tissue from normal and X‐irradiated rat embryos were used to delineate the neuroepithelial source of the cerebellum and trace the earliest cell movements. The cerebellar anlage, crescent shaped, is demarcated by two ventricular landmarks, the anterior extension of the tela choroidea of the fourth ventricle and the embryonic cerebellar fissure. The cerebellar tela choroidea extends from the medullary fourth ventricle posteromedially to the lateral recess of the pontine fourth ventricle anterolaterally. The embryonic cerebellar fissure begins caudally as a single midline incision beneath the fused posterior cerebellar primordium, then splits to follow the unfused cerebellar halves, first separating each from the isthmus then from the pons.The cerebellar primordium is divided into three parts. The lateral cerebellar primordium caps the lateral recess of the fourth ventricle; it is contiguous with the pons medially and separated ventrally from the anlage of the cochlear nuclei by the tela choroidea. The subisthmal cerebellar primordium is situated beneath the isthmus, medially lining the isthmus canal. Laterally and posteriorly, it is continuous with the lateral and postisthmal primordia. The postisthmal cerebellar primordium caps the postisthmal recess of the fourth ventricle and extends to the medullary fourth ventricle. As we shall describe later, each of these primordia is a source of different components of the developing cerebellum.Most cells of the superficially located nuclear transitory zone are labeled with 3H‐thymidine administered on day E14 but not thereafter. A high proportion of the cells of the deeper cortical transitory zone could still be labeled on day E15. This supports the assumption made earlier that the first is composed of differentiating deep neurons, the second of Purkinje cells. The cells of the nuclear transitory zone originate in the lateral cerebellar primordium near the junction with the tela choroidea prior to the formation of the germinal trigone and migrate in a superficial position medially. Beginning on day E16, the nuclear transitory zone splits into two components. One has transversely oriented cells that seem to be the source of a decussating fiber tract, presumably the hook bundle of Russell. The other is composed of longitudinally oriented cells that apparently contribute fibers to the ipsilateral superior cerebellar peduncle. The translocation of the cells of the nuclear transitory zone from the cerebellar surface to its depth, to form the deep nuclei, and the radial migration of the cells of the cortical transitory zone to the surface, to form the Purkinje cell layer, will be described in the succeeding paper.
Embryonic development of the rat cerebellum. II. Translocation and regional distribution of the deep neurons
Authors: Altman Joseph , Bayer Shirley A. 
Published: May 2005

AbstractIn thymidine radiograms and plastic‐embedded sections, the migration of cerebellar deep neurons was traced from their germinal source to their final settling sites. The route proved to be roundabout and three developmental events could be distinguished during the process. First, between days E14 and E16, transversely oriented cells of the nuclear transitory zone move in an arc from the ventrolateral neuroepithelium of the lateral cerebellar primordium in a medial direction. Second, between days E16 and E18, the cells of the rostral component of the nuclear transitory zone assume a longitudinal orientation. We postulated that this is the period of axonogenesis, the longitudinally oriented cells issuing efferents that join the superior cerebellar peduncle ipsilaterally and the transversely oriented cells (representing the neurons of the caudal fastigial nucleus) sending decussating fibers to the uncinate fasciculus (the hook bundle of Russell). Third, between days E18 and E21, the earlier‐produced superficial cells of the nuclear transitory zone and the later‐produced deep cells of the cortical transitory zone (the young Purkinje cells) exchange positions. The descent of the deep neurons is in the direction of the fibers of the inferior cerebellar peduncle, which becomes distributed throughout the cerebellum on day E17. The ascent of the Purkinje cells is in the direction of the external germinal layer, which begins to spread from caudal to rostral on day E17. The three deep nuclei, the lateral (dentate), interpositus, and medial (fastigial), can be distinguished before their descent into the depth of the cerebellum, and by day E22 a small‐celled and a large‐celled subdivision is identifiable in each nucleus.
Embryonic development of the rat cerebellum. III. Regional differences in the time of origin, migration, and settling of Purkinje cells
Authors: Altman Joseph , Bayer Shirley A. 
Published: May 2005

AbstractThe time of origin, site of origin, migratory path and settling pattern of the Purkinje cells of the cerebellar hemispheres, anterior vermis, and posterior vermis were investigated in thymidine radiograms and plastic‐embedded materials from rat embryos ranging in age from 15 to 22 days. In the hemispheres there is a rostral‐to‐caudal cytogenetic gradient: the Purkinje cells of lobulus simplex, crus I, and crus II are produced earlier than the Purkinje cells of the paramedian lobule and paraflocculus, followed by the Purkinje cells of the flocculus. The Purkinje cells of the vermis, in general, are generated later than those of the hemispheres, and with a reverse gradient from caudal to rostral: the Purkinje cells of the posterior vermis (lobules X–VI) being produced ahead of the Purkinje cells of the anterior posteriorly directed wedge of early‐produced Purkinje cells through the vermis.Evidence was obtained that the Purkinje cells of the hemispheres derive from the lateral cerebellar primordium capping the lateral recess of the fourth ventricle anteriorly. The Purkinje cells of the anterior vermis originate from the subisthmal cerebellar primordium medially lining the isthmal canal. The Purkinje cells of the posterior vermis originate in the postisthmal cerebellar primordium overlying the tela choroidea caudally. The young Purkinje cells migrate from the neuroepithelium to the surface of the cerebellum in a strictly caudal‐to‐rostral order, paralleling the spread of the EGL superficially from posteroventral to anterodorsal. This pattern is independent of the time of origin of Purkinje cells. In the posterior vermis the earliest‐settling Purkinje cells of the uvula follow a short radial course, and a discrete Purkinje layer is formed 3 days after they are generated. In the anterior vermis the Purkinje cells of lobulus centralis, which follow an anterodorsal migratory course, are still settling on day E22, 7 days after their production, presumably awaiting the fusion of the cerebellar base anteriorly. The fissura prima forms medially at the interface region of Purkinje cells derived from the postisthmal and subisthmal cerebellar primordia. For 1–2 days after their settling, the Purkinje cells of the newly forming lobules can be distinguished by certain cytological criteria from the cells in the more caudally‐situated, earlier‐settled lobules.
Projections of the entorhinal area to the striatum, nucleus accumbens, and cerebral cortex in the guinea pig
Authors: Sørensen K. E. 
Published: May 2005

AbstractA study of the efferent projections of the entorhinal area in the guinea pig, by using anterograde (autoradiographic tracing of tritiated amino acids) and retrograde(fluorochrome tracing) methods, revealed the following projections: (1) to nonhippocampal cortices: retrosplenial cortex (area 29), cingulate cortex (areas 23, 24), prelimbic cortex (area 32), infralimbic cortex (area 25), perirhinal cortex (areas 35, 36), prepyriform cortex (area 51B), and insular cortex (areas 13–16). All received direct projection; (2) to subcortical targets', distinct terminations were observed in the lateral thalamic nucleus, the striatum, and the accumbens nucleus.In retrograde experiments, the cells giving rise to the projections to the hippocampus were found to He in layers II and III, those projecting to the nonhippocampal cortical regions to originate in layer IV, and those projecting to the striatum and the accumbens to lie in layers V and VI.Many of the efferent projections to the cerebral cortical regions are associated with reciprocal projections from these regions to the superficial layers (I–III) of the entorhinal cortex. The entorhinal efferent projections generally terminate ipsilaterally. A weak termination is, however, present at the contralateral side. The efferent projections of the entorhinal area represent a route for important caudally directed, nonfornical hippocampal output.
Ontogenesis of neurons producing luteinizing hormone‐releasing hormone (LHRH) in the nervus terminalis of the rat
Authors: Schwanzel‐Fukuda Marlene , Morrell Joan I. , Pfaff Donald W. 
Published: May 2005

AbstractImmunoreactive luteinizing hormone‐releasing hormone (LHRH) was first detected at 15 days of gestation in ganglion cells associated with the peripheral, intracranial, and central parts of the nervus terminalis of the rat. LHRH was not detected in any other structure of the central nervous system at this age.In the 17‐day‐old fetal rat, 62% of the total LHRH‐reactive neuronal population was found in ganglion cells of the nervus terminalis. At this same age, immunoreactive beta‐luteinizing hormone (β‐LH) was first seen in gonadotropes of the anterior pituitary gland.At 19 days of gestation, 31% of the total number of LHRH‐reactive neurons observed in the rat brain was found in the nervus terminalis, and immunoreactive processes were first seen in the organum vasculosum of the lamina terminalis and in the median eminence.Our data indicate that from 15 to 19 days of gestation the nervus terminalis is a principal source of LHRH in the fetal rat. Presence of the decapeptide in the nervus terminalis prior to appearance of β‐LH in the anterior pituitary suggests a possible role for LHRH in this system on maturation of the gonadotropes and differentiation of the brain‐pituitary‐gonadal axis.
II. Cortical neurons immunoreactive with antisera against neuropeptide Y are altered in Alzheimer's‐type dementia
Authors: Chan‐Palay V. , Lang W. , Allen Y. S. , Haesler U. , Polak J. M. 
Published: May 2005

AbstractNeurons identified by their immunoreactivity with antisera against neuropeptide Y (NPY) were studied in three selected areas of the cerebral cortex in brains from controls and in senile dementia of the Alzheimer type (ATD). Changes were more profound in temporal cortex than in parietal cortex, and more severe in parietal cortex than in frontal cortex, paralleling the severity of neuritic plaque formation and incidence of neurofibrillary tangles in these regions. NPY‐i neurons became distorted, with enlarged misshapen cell somata and reduced, thickened, and gnarled dendrites. There was a sharp reduction in the extensiveness and delicacy of the axonal plexus; the reorganized axons were haphazard compared to the normal symmetry of these fibers. Besides the alteration in form and sizes, there were also appreciably fewer cells. Nevertheless, the NPY population is not eliminated. Double‐label studies of NPY‐i and thioflavin indicate that NPY‐i fibers can participate in neuritic plaque formation although not all neuritic plaques contained NPY‐i axons and not all NPY‐i axons were associated with plaques. The surviving NPY cells were evident in all cortices examined, thus giving rise to the speculation that these peptide neurons may have unusual survival and reorganization potential even in terminal neurological disease.
Morphological features of lamina V neurons receiving nociceptive input in cat sacrocaudal spinal cord
Authors: Ritz Louis A. , Greenspan Joel D. 
Published: May 2005

AbstractThirty‐six neurons from laminae III‐VII in cat sacrocaudal spinal cord were labeled by intracellular injection of horseradish peroxidase, following physiological characterization. Of these 36 neurons, 24 had cell bodies within lamina V. Twelve lamina V neurons were multireceptive; i.e., they responded differentially to innocuous and noxious mechanical stimuli. Most multireceptive neurons had the following morphological features: (1) large cell bodies; (2) extensive dendritic spreads in all directions; and (3) axons which ascended in the contralateral ventral white matter.Three labeled lamina V neurons were activated only by noxious stimuli. Compared to the multireceptive neurons, these nociceptive‐specific (NS) units had smaller cell bodies but a similar dendritic spread. Seven lamina V neurons were excited by innocuous mechanical stimuli with no evidence of nociceptive input. These seven neurons had less extensive dendritic trees than the multireceptive and the NS neurons. Six neurons labeled in lamina VII (three multireceptive and three NS) contrasted to most lamina V cells by having smaller cell bodies and short, sparsely branched dendrites. Among the lamina VII neurons, there was no obvious morphological feature that distinguished the multireceptive group from the NS group.Fifteen fully stained neurons from laminae III–VII had late discharges which were correlated with C fiber input. The dendrites of three of these neurons extended into laminae II and I; the dendrites of two neurons reached into the inner portion of lamina II; and the dorsal dendrites of the remaining ten neurons extended no further than the nucleus proprius (laminae III and IV). Thus, deeper dorsal horn neurons evincing reliable, excitatory influences from C fibers do not necessarily have superficially situated dendrites.Tests for correlations between size of cutaneous, excitatory receptive field (RF) and dendritic spread revealed a significant positive correlation between the mediolateral extent of dendritic spread and the size of the low‐threshold component of the RF for lamina V neurons.
Topography of regenerating optic fibers in goldfish traced with local wheat germ injections into retina: Evidence for discontinuous microtopography in the retinotectal projection
Authors: Meyer Ronald L. , Sakurai Kari , Schauwecker Elyse 
Published: May 2005

AbstractA small injection of wheat germ agglutinin conjugated to horseradish peroxidase (WGA‐HRP) was injected into dorsal or ventral peripheral retina in normal goldfish and in goldfish with prior optic nerve crush. Serial sections of tectum were subsequently taken for horseradish peroxidase (HRP) histochemistry 18 hours after injection and studied with light microscopy and densitometric reconstructions. In normals, a small, sharply delineated patch of product 200–300 μm wide was observed at the appropriate medial or lateral periphery of tectum. This product filled the entire SFGS, the main optic termination layer, and fell off abruptly at its edges. No labelling was detected in the optic pathways.In regenerates at about 20 days after nerve crush, these retinal injections yielded product that was dispersed across 1,000 μm or more of tectum but not in a uniform fashion. The densest product was biased toward the appropriate tectal position while product of intermediate density was mainly distributed along a path from the anterior end of tectum to this region. Product in the inappropriate half of tectum was much lighter and typically fiberlike in appearance. By about 40 days, product had condensed considerably at roughly the correct region of tectum but it was not as sharply delimited as in normals. Dense label occupied a single area about twice that of normals and exhibited flanking regions of light label extending for several hundred micrometers. At 59–148 days, a further condensation was observed but into more than one patch of product. The patches were of variable size and consisted of sharply delimited dense product which filled the entire SFGS at each position. Morphologically, these patches bore a remarkable resemblance to the ocular dominance columns previously seen in this system.
The effects of monocular deprivation on the size of GAD + neurons in the cat's dorsal lateral geniculate nucleus
Authors: Robson J. A. , Martin‐Elkins C. L. 
Published: May 2005

AbstractPrevious studies have shown that suturing one eyelid closed in a newborn kitten results in profound changes in the development of the visual system. Among these is a retardation in the growth of neurons in the layers of the dorsal lateral geniculate nucleus receiving retinal input from the closed eye. Moreover, the greatest effect appears to be in the largest neurons. The present study examines the effects of monocular deprivation en the perikaryal size of select group of small lateral geniculate neurons, GABAergic neurons, that may be interneurons. These cells were selectively labeled by an antiserum to glutamic acid decarboxylase (GAD) and immunocytochemical methods. The results demonstrate that GAD+ neurons are among the smallest in the lateral geniculate nucleus and that they are insensitive to the effects of monocular deprivation. That is, GAD+ neurons in deprived laminae A and A1 are similar in size to those in the corresponding, nondeprived laminae. These findings are consistent with the hypothesis that GAD+ neurons are interneurons and therefore not subject to binocular competition in the visual cortex. This interpretation, however, is complicated by additional studies of the postnatal development of GAD+ neurons which reveal that GAD+ neurons grow to their adult size relatively early, before the onset of the critical period. Thus the insensitivity of the perikarya of GAD+ neurons to monocular deprivation may be attributable to their precocious growth.