bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrastructure of mouse vallate taste buds: II. Cell types and cell lineage
Authors: Delay Rona J. , Roper Stephen D. , Kinnamon John C. 
Published: January 2005

AbstractThe lifespan of cells in the mouse taste bud was examined with high‐voltage electron microscopic (HVEM) autoradiography (ARG) after giving a single injection of 3H‐thymidine. Animals were killed at 1 hour, 6 hours, 12 hours, 24 hours, and then daily up through 10 days postinjection. Lingual tissues were prepared for HVEM ARG so that we could identify and characterize labeled cells. Four categories of taste cells were identified: basal, dark, intermediate, and light cells. Basal cells were polygonal cells located near the basolateral sides of the taste buds and were characterized primarily by the presence of filaments attached to the nuclear envelope. Dark and light cells had the typical features described by previous authors. Intermediate cells had features in between those of dark and light cells.Over 90% of the cells labeled in the first 2 days following injection of 3H‐thymidine were basal cells. Labeled dark cells appeared 6 hours after injection, reached their peak incidence at the fourth day postinjection, and then gradually decreased. Labeled intermediate cells were identified after the appearance of dark cells (12 hours) and reached a peak incidence at the fifth day after injection of 3H‐thymidine. Lastly, labeled light cells were first observed on the fourth day postinjection and continued to increase until the tenth day, when they constituted 45% of the labeled cells. These data support the hypothesis that there is one cell line in the mouse vallate taste bud that undergoes morphological changes in its lifespan.
The projection of frontal cortical oculomotor areas to the superior colliculus in the domestic cat
Authors: Hartwich‐Young Rosi , Weber Joseph T. 
Published: January 2005

AbstractThe projection of frontal cortical oculomotor areas to separate laminae of the superior colliculus was examined in adult domestic cats. Following the placement of WGA‐HRP/HRP injections within the superficial, intermediate, and deep layers of the superior colliculus, several observations may be made regarding the frontal corticotectal projection in the cat. Large injections including all of the collicular layers result in the retrograde labeling of neurons in frontal cortical areas that have been suggested previously to be analogous to the frontal eye fields in monkeys. These areas are a portion of the ventral bank and lip of the cruciate sulcus, including a small portion of the medial wall of the hemisphere, and the medial and lateral banks and fundus of the presylvian sulcus. The same pattern of retrograde labeling in frontal cortical areas is seen when the injection sites are restricted to either the intermediate or deep collicular layers. That is, different frontal cortical areas of the cat project separately but not differentially upon different collicular laminae. The greates numbers of labeled neurons within frontal cortical oculomotor areas are observed following injections placed laterally within the caudal portion of the superior colliculus, regardless of whether the injection sites are located within the intermediate or deep collicular layers. Injections restricted to the superficial gray layer do not result in retrograde labeling in any of the frontal cortical oculomotor areas of the cat. These results are discussed in terms of the patterns of visuomotor integration specific to the cat, as well as in relation to previous evidence showing similarities between frontal cortical areas in cats and monkeys.
Effects of monocular deprivation on the cat's geniculate neurons projecting to both areas 17 and 18
Authors: Geisert Eldon E. 
Published: January 2005

AbstractWhen a kitten is reared with one eyelid sutured closed, there are profound changes in the developing visual system. In the lateral geniculate nucleus, the neurons in the laminae innervated by the deprived eye are smaller than normal, and some of these neurons may lose connections with the visual cortex. In the present study a variety of double label retrograde transport methods were used to define the effects of monocular deprivation on cortical projections of geniculate neurons. One marker was injected into area 17 and the other was injected into area 18. Neurons projecting to area 17 are on average 16.4% smaller than those in the nondeprived laminae. The neurons that normally would project to both areas 17 and 18 by an axon that branches are the most severely affected by monocular deprivation. These cells are nearly 40% smaller than their counterparts in the nondeprived laminae, and many of the neurons appear to lose their projection to one of the cortical areas. These neurons may be at a distinct disadvantage, since they must compete with neurons from the nondeprived laminae for a considerable amount of cortical territory in two different cortical areas. This competition may be so severe that some of the neurons are no longer capable of maintaining connections with both cortical areas.
Neural inputs into the temporopolar cortex of the rhesus monkey
Authors: Morán M. A. , Mufson E. J. , Mesulam M.‐M. 
Published: January 2005

AbstractTemporopolar cortex (TP) can be subdivided into agranular, dysgranular, and granular components. The telencephalic input into the temporopolar cortex arises from the orbitofrontal and medial frontal regions, modality‐specific visual and auditory association areas, paralimbic regions, the piriform olfactory cortex, the hippocampus, the amygdala, the claustrum, and the basal forebrain.Afferents from limbic and paralimbic regions are directed mostly to the agranular and dysgranular sectors of the temporal pole, whereas afferents from isocortical association areas are distributed predominantly within the granular sector.The temporopolar cortex provides a site for the potential convergence of sensory and limbic inputs. Auditory inputs predominate in the dorsolateral part of the temporopolar cortex whereas visual inputs become prominent only in the ventral portions of this region. Olfactory inputs are directed mostly to the medial parts of the temporal pole. These medial parts also receive more extensive projections from the amygdaloid nuclei.
Spatial distribution of axon collaterals of single inferior olive neurons
Authors: Rosina A. , Provini L. 
Published: January 2005

AbstractThe aim of this study was to define the overall distribution pattern of the axon collaterals of single inferior olive (IO) neurons in relation to the multiple somatotopic maps defined by the climbing fiber (CF) input through the cerebellar cortex.In a previous study (Rosina and Provini: Brain Res. 289:45–63, '83), it was shown that the IO neurons supply interlobar collaterals to pairs of somatotopically related areas in the intermediate part of the anterior lobe (PIAL), in the paramedian lobule (PML), in crus II, and in the simple lobule, within strips C1 to D2. The residual branches then could either distribute within single folia or to adjacent folia within each somatotopically defined cerebellar area or both. We studied whether or not the IO axons branch over neighboring folia of the face‐forelimb (FL) areas of PIAL and PML and how this interfolial branching relates to the interlobar collateralization by using the multiple fluorescent retrograde tracing technique.The main results of the study were as follows: (1) the axons from neurons in IO subdivisions that are related to strips C1–C3 give off two interfolial branches in the FL area of PIAL and practically no interfolial collaterals are given in the FL area of PML; and (2) the neurons that give off interfolial collaterals also give interlobar branches.From these data we have inferred the general branching pattern of the IO neurons that convey FL information to PIAL and PML. Each neuron gives off two interlobar collaterals: the branch directed to PIAL splits again into two interfolial collaterals, while each of these three collaterals should give off about three branches within each target folium to account for the ten collaterals estimated to be present in the cat.The distribution pattern of IO axon collaterals proposed here suggests that the same CF‐relayed information may interact, at the Purkinje cell level, with different sets of mossy fiber inputs. The effect of this interaction would be to modulate the motor commands forwarded to specific muscle groups in relation to the different conditions under which a given movement is executed.
Distribution and partial characterization of FMRFamide‐like peptides in the stomatogastric nervous systems of the rock crab, Cancer borealis, and the spiny lobster, Panulirus interruptus
Authors: Marder Eve , Calabrese Ronald L. , Nusbaum Michael P. , Trimmer Barry 
Published: January 2005

AbstractThe distribution of FMRFamide‐like peptides was studied in the complete Stomatogastric nervous system [the paired commissural ganglia, single oesophageal ganglion, and the single Stomatogastric ganglion (STG)] of two decapod crustacean species, the spiny lobster Panulirus interruptus and the rock crab Cancer borealis, by using immunocytochemical techniques. Antiserum 231 from the O'Donohue laboratory and antiserum 671C (described here) gave essentially the same staining patterns.In the commissural ganglia of both species there were ten to 20 stained neurons and dense neuropilar staining. The oesophageal ganglion of the crab had four stained neurons. Lucifer Yellow backfills followed by immunostaining showed that the two larger stained neurons of the oesophageal ganglion sent processes into the inferior ventricular nerve. The two smaller neurons sent processes into the inferior oesophageal nerves. The oesophageal ganglion of the lobster had two stained neurons that sent processes into the inferior ventricular nerve as well. None of the somata of the STG stained in either species, but in both species stained fibers were seen in the Stomatogastric nerve that entered the STGs and ramified profusely throughout the neuropil. In some preparations of the crab, a stained fiber was visible in the dorsal ventricular nerve.The amounts of the FMRFamide‐like peptides found in all regions of the nervous system of P. interruptus and C. borealis were determined by radioimmune assay (RIA). Column chromatography and high‐performance liquid chromatography suggest that, in both species, much if not all of the RIA‐assayable material is accountable for by peptides that are larger and more hydrophobia than FMRFamide.
Amygdalofugal and amygdalopetal connections with modality‐specific visual cortical areas in macaques (macaca fuscata, M. mulatta, and M. fascicularis)
Authors: Iwai Eiichi , Yukie Masao 
Published: January 2005

AbstractThe origins and terminations of the amygdaloid connections with the modality‐specific visual cortical areas TEa (anterior TE area), TEp (posterior TE area), TEO, V4, V2, MST (medial superior temporal visual area), MT (middle temporal visual area), and V1 were studied in macaques. These were compared with the amygdaloid connections of a vision‐related polysensory area TG by making cortical injections of horseradish peroxidase (HRP) and incubating the sections with tetramethylbenzidine (TMB) as the chromogen. Both areas TEa and TEp receive a major projection from the lateral basal nucleus and a minor one from the accessory basal nucleus of the amygdaloid complex, whereas these areas send a major projection to the lateral nucleus and a minor one to the lateral basal nucleus. Areas TEO, V4, V2, MST, MT, and V1 receive projections only from the lateral basal nucleus; none of them project to any amygdaloid nucleus. Thus, the amygdalofugal projections are more widespread and more complex than the amygdalopetal projections. These findings indicate that the connections between the amygdaloid nuclei and the visual areas are generally nonreciprocal and underlie the importance of a feedback mechanism from the amygdala to the visual cortical areas in visual information processing. There appears to be a caudorostral (occipitotemporal) gradient in the distribution and density of the amygdaloid projections, which become progressively more widespread and heavier among the progressively more rostral visual areas (from area V1 to area TEa).The amygdaloid connections with area TG are distinctly different from the connections with the visual areas. Area TG is reciprocally connected mainly with the periamygdaloid cortex, and with the lateral, accessory basal, and medial basal nuclei of the amygdala as well.
Localized changes in olfactory bulb morphology associated with early olfactory learning
Authors: Woo Cynthia C. , Coopersmith Robert , Leon Michael 
Published: January 2005

AbstractYoung rats exposed to an odor while receiving reinforcing stimulation come to approach that odor upon subsequent presentation. In addition, such pups have increased 14C‐2‐deoxyglucose (2DG) uptake within focal areas of the glomerular layer in response to that odor, compared to control animals experiencing the odor for the first time. In this study, the morphology of the glomerular areas underlying these 2DG foci was examined to determine whether early olfactory learning imposed local structural changes that could produce the enhanced 2DG uptake. Alternate sections either were processed with a silver and a Nissl stain to label both cell bodies and their processes or were histochemically treated for the mitochondrial enzymes cytochrome oxidase (CO) or succinic dehydrogenase (SDH) to define the glomerular core of the bulb; 2DG autoradiographs were aligned with adjacent stained sections, and regions underlying the high 2DG uptake foci were examined. In odor‐familiar animals, large glomerular clusters that protruded into the external plexiform layer or the olfactory nerve layer were associated with the focal areas of increased 2DG uptake. Morphometric analysis of these regions revealed that the glomerular layer underlying the foci of high 2DG uptake was 30% wider in odor‐familiar animals than comparable areas in odor‐unfamiliar animals; the cross‐sectional areas of individual glomeruli were 21% larger in odor‐familiar animals. The foci of enhanced 2DG uptake therefore appear to be associated with groups of enlarged glomeruli. These data demonstrate that early olfactory learning influences the morphology of the olfactory bulb.
Effects of a lengthy period of undernutrition from birth and subsequent nutritional rehabilitation on the synapse: Granule cell neuron ratio in the rat dentate gyrus
Authors: Ahmed M. G. E. , Bedi K. S. , Warren M. A. , Kamel M. M. 
Published: January 2005

AbstractRecent evidence showing alterations in spatial memory due to a period of undernutrition during early life has implicated the hippocampus as one of the brain centres that may be particularly adversely affected. However, there arc very few quantitative morphological studies that have examined the neuronal and synaptic populations of the hippocampi from undernourished animals. We decided to carry out such experiments, paying particular attention to the granule cell of the dentate gyrus.Male rats were undernourished from the 18th day of gestation until 21, 75, or 150 days or age. Some of these previously undernourished rats were nutritionally rehabilitated between 150 and 250 days of ago. Groups of wellfed control and experimental rats were killed by intracardiac perfusion with 2.5% sodium‐cacodylate‐buffered glutaraldehyde. The right hippocampus from each rat was dissected out and processed for electron microscopy. Stereological procedures at the light, and electron microscopical levels were used to estimate the numerical densities of granular cell neurons and molecular layer synapses in the dorsal lip of the dentate gyrus. These estimates were used to calculate synapse: neuron ratios.There were 5,056 ± 347 (mean ± SE) and 5,002 ± 190 synapses per neuron in 21‐day‐old control and undernourished rats, respectively. By 75 days these values had increased to 9,215 ± 588 and 6,683 ± 237. The difference was statistically significant. By 150 days of age the value for control animals had fallen once again to 6,518 ± 209 whereas undernourished rats had increased slightly to 7,689 ± 288 (P <.01); 250‐day‐old rats, previously undernourished from birth to 150 days of age, showed a substantial increase in the synapse: neuron ratio during the period of nutritional rehabilitation. Thus these nutritionally rehabilitated rats had 9,407 ± 365 synapses per neuron whereas age‐matched controls had only 6,323 ± 239 (P <.01).These ressults indicate that the rat dentate gyrus is vulnerable to undernutrition even during the postweaning period and that a lengthy period of undernutrition can alter the developmental growth curve for synapse: neuron ratios.
Response of septal cholinergic neurons to axotomy
Authors: Armstrong David M. , Terry Robert D. , Deteresa Richard M. , Bruce Gordon , Hersh Louis B. , Gage Fred H. 
Published: January 2005

AbstractIn the present study we employed quantitative morphometric techniques to assay the response of septal cholinergic neurons following unilateral transection of the fimbria/fornix and supracallosal stria. Analysis of 50‐μm‐thick tissue sections with a Quantimet 920 image analysis system demonstrated a reduction in ChAT immunoreactivity as early as 1 day following denervation. This decrease was associated with a drop in the number of labeled cells ipsilateral to the lesion and a decrease in the area of cholinergic perikarya on the lesioned and nonlesioned side of the septum. The response at 1 day, however, was transient, and at 4 days the number of labeled neurons was not significantly different from controls. By 8 days we observed a dramatic reduction in the number and size of ChAT‐positive cells ipsilateral to the lesion and a reduction in the size of cholinergic perikarya on the contralateral (i.e., nonlesioned) side. These values persisted throughout the remainder of the study.To assess more completely the morphologic response of neurons to axotomy than can be determined in 50‐μm‐thick tissue sections, we embedded the adjacent immunolabeled tissue section in Epon and then serially sectioned it to a thickness of 0.75–1.0 μm. By using this method, we wore able to measure the area, length, and width of the cell, the area of the nucleus and nucleolus, and the position of the nucleus (i.e., eccentricity). Measurements were performed on ChAT‐labeled and nonlabeled cells. The results of our studies demonstrate that cholinergic and noncholinergic cells responded to axotomy in a characteristic yet different fashion from each other and that this response could be quantitatively assayed. In general, labeled and non‐labeled cells on the lesioned side of the septum shrink in response to denervation. This shrunken state was reflected in measurements of cellular area, length, width, and nuclear area. Moreover, other measurements of cellular morphology (i.e., area of the nucleolus, position of the nucleus) indicate that none of the neuronal populations examined in the present study displayed morphologic evidence of regeneration.Our results indicate a dramatic loss of cholinergic perikarya ipsilateral to the lesion. Moreover, although a few neurons do persist they do so in a shrunken state. These data provide an essential baseline for the second study in this series, which will evaluate the effect of nerve growth factor on the survival of denervated septal neurons.
Selective projections from the cat red nucleus to digit motor neurons
Authors: McCurdy M. L. , Hansma D. I. , Houk J. C. , Gibson A. R. 
Published: January 2005

AbstractClassical studies of the cat rubrospinal tract describe dense terminations in spinal laminae V–VII and an absence of any significant projection to lamina IX. In contrast, our recent studies, utilizing the anterograde transport of wheat germ agglutinin conjugated with horseradish peroxidase, have demonstrated a consistent and circumscribed area of label in lamina IX at caudal cervical segments.The present study was undertaken to determine the distribution of rubrospinal terminals among motor neurons in lamina IX as well as to identify the likely target muscles of those motor neurons located near rubrospinal terminals. We injected wheat germ agglutinin‐horseradish peroxidase into the red nucleus and unconjugated horseradish peroxidase into selected forearm muscles of the same side of the body. The locations of rubrospinal terminals showing anterograde label on one side of the spinal cord could then be compared with the locations motor neurons showing retrograde label on the opposite side of the cord.The results demonstrated a clear focus of rubrospinal terminals in the lateral and dorsal portions of the ventral horn beginning at C8 and extending through rostral T1. No other segments of the spinal cord showed a focus of rubrospinal terminations in lamina IX. Retrogradely labeled motor neurons from the muscle injections showed that the rubrospinal terminals overlap extensively with motor neuronal pools supplying distal forearm muscles. Several lines of evidence indicate that the terminals are from rubrospinal fibers and are not due to transneuronal transport.
Characterization of HRP‐labeled globular bushy cells in the cat anteroventral cochlear nucleus
Authors: Smith Philip H. , Rhode William S. 
Published: January 2005

AbstractWe report on the anatomical and physiological features of globular bushy cells in the posterior division of the anteroventral cochlear nucleus based on the characteristics of 20 cells from this population. Each of these cells was recorded from and characterized intracellularly and/or extracellularly, injected with horseradish peroxidase, and studied at the light and/or electron microscopic level. Intracellular records from the vicinity of the globular bushy cell body displayed large, fast synaptic potentials, and in some instances a larger presumed action potential both in silence and during short tone stimulation. Intraaxonal recordings displayed large action potentials in addition to small, fast potentials, which evidence indicates may be the decrementally conducted subthreshold synaptic potentials. Both recording situations indicated that these auditory nerve inputs need not be suprathreshold. Bushy cells with high characteristic frequencies (CFs > 3 kHz) typically showed primary like‐ with‐notch responses to short tones at CF or on‐type L responses if the sustained level of discharge after the notch was not as robust. Low‐CF bushy cells phase‐locked after a well‐timed onset spike. Light microscopic anatomy revealed a typically oval cell body giving rise to one or two primary dendrites that branched profusely and an axon that gave off no collaterals within the cochlear nucleus before entering the trapezoid body. Electron microscopic analysis showed a high concentration of large, round, vesicle‐containing terminals on the cell body and primary dendrite while the population of terminals on the initial segment and sparsely covered distal dendrites was made up mostly of flat and pleomorphic vesicle‐containing terminals.