Olfactory Bulb

The titanium contents in the sub-brain regions including olfactory bulb, cerebral cortex, hippocampus, and cerebellum were determined by inductively coupled plasma mass spectrometry (ICP-MS). Results indicated that the instilled TiO(2) directly entered the brain through olfactory bulb in the whole exposure period, especially deposited in the hippocampus region. After exposure for 30days, the pathological changes were observed in the hippocampus and olfactory bulb using Nissl staining and transmission electron microscope.  

Lordotic response after these different hormonal and neonatal surgical treatments, as well as the volume or number of neurons in facilitatory (ventromedial nucleus of the hypothalamus [ VMN]) and inhibitory (the intermediate region of the lateral septum [ LSi] and accessory olfactory bulb [ AOB]) nuclei involved in lordosis was studied in adults.  

Such familiar stimuli elicit reduced behavioral responses, a change likely related to NA-dependent plasticity in the olfactory bulb (OB).  

Here, we examined how synapses of a single neuronal type, the granule cell in the olfactory bulb, develop during their integration into the immature circuit of the newborn and the fully mature circuit of the adult rat.  

The existence of the endothelin system and catecholaminergic neurons in the olfactory bulb suggests that endothelins may modulate noradrenergic transmission and diverse olfactory mediated processes. In the present work we studied the effect of endothelin-1 and -3 on neuronal norepinephrine release and the short-term regulation of tyrosine hydroxylase in the olfactory bulb. Taken together present findings show a clear interaction between the endothelin system, and the catecholaminergic transmission in the olfactory bulb.  

However, small numbers of projection neurons were generated in the forebrain, especially in the piriform cortex, which is the main target of the olfactory bulb..  

Although the hippocampus and olfactory bulb are most commonly studied in the context of adult neurogenesis, there is an increasing body of evidence in support of neurogenesis occurring outside of these two regions. The current study expands on previous data by showing newborn neurons with a mature phenotype are located in several olfactory and limbic structures outside of the hippocampus and olfactory bulb, where we previously described doublecortin/bromodeoxyuridine immature neurons.  

To investigate the circuitry involved in detecting odorants in the rodent brain, we developed a method using manganese-enhanced MRI (MEMRI) to map the flow of neural information from the olfactory sensory neurons (OSNs) to the central layers of the olfactory bulb. Using the time course of the MRI signal, we generated maps of Mn(2+) accumulation in the olfactory bulb for both glomerular and mitral cell layers.  

Glutamate and norepinephrine (NE) are believed to mediate the long-lasting synaptic plasticity in the accessory olfactory bulb (AOB) that underlies pheromone recognition memory.  

Two classes of receptor neurons are apically and basally placed in the vomeronasal epithelium, express Gi2alpha and Goalpha proteins and V1R and V2R receptors and project to the anterior and posterior portions of the accessory olfactory bulb, respectively. Apart from common vomeronasal recipient structures in the amygdala, only the anterior accessory olfactory bulb projects to the bed nucleus of the stria terminalis and only the posterior accessory olfactory bulb projects to the dorsal anterior amygdala.  

Spikes were evoked in rat olfactory sensory neuron (OSN) populations by electrical stimulation of the olfactory bulb nerve layer in pentobarbital anesthetized rats.  

The initial synapse in the olfactory system is from olfactory nerve (ON) terminals to postsynaptic targets in olfactory bulb glomeruli. Thus, the transformation of inhibitory inputs to postsynaptic excitation in ET cells may enhance intraglomerular inhibition of mitral/tufted cells, the main output neurons in the olfactory bulb, and hence shape signaling to olfactory cortex..  

Brain perfusion computed tomography (CT) scanning was performed in a mongrel dog and a golden retriever that were diagnosed with third ventricular tumor and olfactory bulb tumor, respectively, by contrast-enhanced CT.  

Microarray analysis may be a useful tool to identify some candidate genes related to the development of olfactory bulbs. In the present study, gene expression profiles of olfactory bulbs from postnatal day 1 (P1) rats and postnatal day 35 (P35) rats were analyzed by oligonucleotide-microarray and expression levels of some selected genes were also confirmed by RT-PCR and in situ hybridization. Among these genes, 76 were up-regulated and 130 were down-regulated three-folds or more at P1 olfactory bulbs. Among them, 2 interesting genes (neurogenic differentiation 1 and retinoid acid receptor alpha) were localized in the P1 olfactory bulb by the use of in situ hybridization technique. Our results may provide basic information to identify genes associated with functional growth of olfactory bulbs..  

We describe here the advantages and weaknesses of the olfactory bulb as a model to study neurovascular coupling using TPLSM.  

(3) Calcium-sensitive dyes that are internalized into olfactory receptor neurons in the nose will, after several days, be transported to the nerve terminals of these cells in the olfactory bulb glomeruli.  

Concerning the primary olfactory structures, the CoA receives inputs from both the main olfactory bulb and the accessory olfactory bulb (AOB), while the MeA is innervated by cells only from the AOB.  

In the olfactory bulb, apoptotic cell-death induced by sensory deprivation is restricted to interneurons in the glomerular and granule cell layers, and to a lesser extent in the external plexiform layer, whereas mitral cells do not typically undergo apoptosis. With the goal to understand whether brain-derived neurotrophic factor (BDNF) mediates mitral cell survival, we performed unilateral naris occlusion on mice at postnatal day one (P1) and examined the subsequent BDNF-immunoreactive (BDNF-ir) profile of the olfactory bulb at P20, P30, and P40. Western blot analysis revealed the presence of primarily proBDNF in the olfactory bulb.  

This study presents a cytoarchitectural atlas of the brain of the common vampire, Desmodus rotundus murinus, in the frontal plane, serially between the olfactory bulb and the medulla oblongata.  

Based on axonal projections to the olfactory bulb of the brain, as well as expression of olfactory receptors and the olfactory marker protein, it is considered a chemosensory subsystem.  

MATERIAL/METHODS: Olfactory ensheathing cells from the olfactory bulb were cultured in DMEM/F-12 medium and purified with cytosine arabinoside (Ara-c). RESULTS: After transecting the olfactory nerve, there was no horseradish peroxidase staining in the olfactory bulb; some OEPs disappeared. Five days after surgery, there was no horseradish peroxidase staining in the olfactory bulb of any animal. Some horseradish peroxidase staining in the olfactory bulb and OECs was detected; more growth associated protein-43 marked olfactory receptor neurons were visible.  

In the mammalian olfactory system, intrabulbar projections (IBPs) mediated by a class of external tufted cells (ET cells) specifically link isofunctional odor columns within the same olfactory bulb. Thus, intrabulbar projecting ET cells can shape olfactory bulb output through intraglomerular modulation of MT cells..  

Kallmann syndrome (KS) combines hypogonadism due to gonadotropin-releasing hormone deficiency, and anosmia or hyposmia, related to defective olfactory bulb morphogenesis.  

The distribution of the synGAPalpha1 and beta (beta1-4) isoforms in the adult rat brain was clearly different in cerebellum, hippocampus, cerebral cortex, septum and olfactory bulb.  

We conclude that, in addition to intrinsic growth potential, the presence of an aligned substrate to the target structure is a fundamental prerequisite for appropriate restoration of connectivity with the olfactory bulb.  

The mammalian telencephalon, which comprises the cerebral cortex, olfactory bulb, hippocampus, basal ganglia, and amygdala, is the most complex and intricate region of the CNS.  

We examined the mRNA expression profile of mGluR1a/b in microdissected layers and acutely isolated mitral cells in the developing mouse olfactory bulb.  

Recent in vivo and in vitro studies have challenged existing models of olfactory processing in the vertebrate olfactory bulb and insect antennal lobe.  

We recently showed a loss of neuronal nitric oxide synthase (nNOS) protein in the olfactory bulb of reeler mutants and advanced the hypothesis that the Reelin and NO signalling pathways may influence each other. We now studied the distribution of NO sensitive guanylyl cyclase (NOsGC), Reelin and its receptor Apolipoprotein E2 (ApoEr2) in the olfactory bulb by multiple fluorescence labelling and tested whether nNOS and ApoEr2 colocalize in this area. We also essayed the protein content of NOsGC in the reeler olfactory bulb and tested whether there are any changes in nNOS and NOsGC protein in other reeler brain areas. olfactory bulb interneurons expressing ApoEr2 and nNOS are only few in the glomerular layer but represent the large majority of granule cell layer interneurons. These data further support the hypothesis of a reciprocal signalling between Reelin/NOsGC and ApoEr2/nNOS expressing neurons to affect olfactory bulb activity. We also show that a significant rise in NOsGC content accompanies the decrease of nNOS protein in the reeler olfactory bulb. Thus, the influence that the deficit of extracellular Reelin seems to exert on nNOS and its receptor is not limited to the olfactory bulb but is a general feature of the reeler brain..  

A comprehensive model has yet to emerge, but it seems likely that numerous mechanisms contribute to the specificity of olfactory sensory neuron (OSN) axon innervation of the olfactory bulb. However, in adults it is expressed at different levels across the olfactory epithelium and in restricted glomeruli across the olfactory bulb, suggesting an important role in the formation and maintenance of OSN connections to the olfactory bulb.  

Its role in important brain structures such as the midbrain, the lateral septal complex, the hypothalamus, the olfactory bulb, the pons, the choroid plexus, the nucleus pallidus, the striatum and the amygdala, the nucleus accumbens and the anterior cingulated gyrus candidate it as a promising target for genetic association studies.  

Canine olfactory bulb-derived neural progenitor cells (NPCs) isolated from dog brains were expanded ex vivo and implanted into the caudate nucleus/thalamus or cortex of allogeneic dogs. Canine olfactory bulb-derived NPCs labeled with micron-sized superparamagnetic iron oxide particles were detected by magnetic resonance imaging both in vivo and postmortem. When mucopolysaccharidosis VII canine olfactory bulb-NPCs that were genetically corrected with a lentivirus vector ex vivo were transplanted into mucopolysaccharidosis VII recipient brains, they were detected histologically by beta-glucuronidase expression in areas identified by antemortem magnetic resonance imaging tracking.  

Projections from the olfactory bulbs have been traditionally described as 'nontopographically organized'. Four receptor expression zones have been described in the olfactory epithelium, maintained in the main olfactory bulb, but none in the olfactory cortex. Topography was not observed in the four zones of the main olfactory bulb. Areas of the rostral telencephalon were shown to receive simultaneous inputs from the main and accessory olfactory bulbs..  

The GnRH-I promoter was active in the forebrain area, including the olfactory bulb-terminal nerve area and peripheral preoptic areas; the GnRH-II promoter was active in the midbrain; and the GnRH-III promoter was active in the olfactory bulb.  

Following previous data, we have proposed that gamma band oscillations in mammals could subserve a gating function for the transfer of information between the olfactory bulb (OB) and the anterior piriform cortex (aPC), which are functionally coupled.  

Slack-A mRNAs were enriched in the brainstem and olfactory bulb and detected at significant levels in four different brain regions. Using an antibody that recognizes all amino-termini isoforms of Slack, Slack immunoreactivity is present at locations that have no Slack-B-specific staining, including olfactory bulb glomeruli and the dendrites of hippocampal neurons, suggesting that Slack channels with alternate amino-termini such as Slack-A channels are present at these locations.  

We found that the lack of CREB/CREM genes is accompanied by anatomical defects in specific layers of the olfactory bulb, hippocampus and cerebral cortex.  

Previously, we showed that most parvalbumin positive cells in the external plexiform layer (EPL) of the mouse main olfactory bulb (MOB) were anaxonic but displayed some patch-like betaIV-spectrin and sodium channel cluster positive segments on their dendrites.  

It has been proposed that olfactory bulb mitral cells exhibit this functional circuitry, with excitation from one glomerulus and inhibition from a broad field of glomeruli within reach of the lateral dendrites.  

provide evidence that lateral inhibition in the olfactory bulb selectively acts between sparse populations of principal neurons without regard to spatial relations..  

Here, we asked whether dendrodendritic synaptic interactions in the olfactory bulb vary with brain and behavioral states. To examine the state-dependent change of the dendrodendritic synaptic transmission, we monitored changes in field potential responses in the olfactory bulb of urethane-anesthetized and freely behaving rats. In addition, the frequency of the spontaneous oscillatory activity of local field potentials and periodic discharges of mitral cells in the olfactory bulb shifted in synchrony with shifts in the neocortical brain state. These results provide evidence that behavioral state-dependent global changes in cholinergic tone modulate dendrodendritic synaptic inhibition and the information processing mode in the olfactory bulb..  

The present study examined the impact of ovarian aging using an ex vivo model system, where astrocytes were derived from the olfactory bulb of young, reproductively competent females and reproductive senescent females.  

Four measures of olfactory capability, that is, the number of olfactory lamellae, the surface area of the olfactory epithelium, the mass of the olfactory bulb, and the mass of the olfactory rosette were compared between individual species and groups, comprised of species with similar habitat and/or lifestyle. There was no significant correlation between either olfactory bulb or rosette mass and habitat type. However, some groups had significantly larger olfactory bulb or rosette masses than others.  

The entorhinal cortex (EC) receives afferent projections from the main olfactory bulb; this constitutes an olfactory pathway to the hippocampus. Recently, a centrifugal projection from CA1 to the accessory olfactory bulb has been identified using anterograde tracers. In the study reported herein, experiments using anterograde tracers confirm this projection, and injections of retrograde tracers show the distribution and morphology of a population of CA1 and ventral subicular neurons projecting to the accessory olfactory bulb of rats. These results extend previous descriptions of hippocampal projections to the accessory olfactory bulb by including the ventral subiculum and characterizing the morphology, neurochemistry (double labeling with somatostatin), and distribution of such neurons. These data suggest feedback hippocampal control of chemosensory stimuli in the accessory olfactory bulb.  

In this study, we use olfactory bulb neurons as a useful model, which undergo strong neurogenesis throughout adulthood. Our research demonstrated that low level of STAT3 expression facilitates the terminal differentiation of olfactory bulb neurons as well as induces the generation of neurons from neural stem cells, which can be potentially used in future therapies.  

Heavy P2X(5) receptor immunostaining was observed in the mitral cells of the olfactory bulb; cerebral cortex; globus pallidum, anterior cortical amygdaloid nucleus, amygdalohippocampal area of subcortical telencephalon; anterior nuclei, anteroventral nucleus, ventrolateral nucleus of thalamus; supraoptic nucleus, ventromedial nucleus, arcuate nucleus of hypothalamus; substantia nigra of midbrain; pontine nuclei, mesencephalic trigeminal nucleus, motor trigeminal nucleus, ambiguous nucleus, inferior olive, hypoglossal nucleus, dorsal motor vagus nucleus, area postrema of hindbrain; Purkinje cells of cerebellum; and spinal cord.  

An odorant's code is represented by activity in a dispersed ensemble of olfactory sensory neurons in the nose, activation of a specific combination of groups of mitral cells in the olfactory bulb and is considered to be mapped at divergent locations in the olfactory cortex. Mouse olfactory epithelial explants are cocultured with a brain slice that includes the olfactory bulb and olfactory cortex areas and maintains the central olfactory pathway intact and functional. Axons of olfactory receptor neurons grow out of the explant and rewire into the olfactory bulb.  

In addition, field potentials induced in the three sites in response to paired-pulse stimulation of the olfactory bulb were recorded in order to assess short-term inhibition and facilitation in these structures.  

A non-homogenous exposure of the test structure to the odours gives rise to a time and spatial dependence of the response of the different glomeruli strikingly similar to patterns observed in the olfactory bulb.  

However, in the olfactory bulb (OB), GFP+ neurons were observed with the CMV but not the tetON vector.  

Investigation at the molecular level revealed impaired juxtaparanodal clustering of Caspr2 and Kv1.1/1.2 in the hippocampus, entorhinal cortex, cerebellum and olfactory bulb, with diffusion into the internode. Caspr2 and Kv1.1 levels were reduced in the cerebellum and olfactory bulb.  

Drug concentrations in the plasma and six different regions of the brain tissues, i.e., olfactory bulb, olfactory tract, anterior, middle, and posterior segments of cerebrum and cerebellum were analyzed by LC/MS method after solid phase extraction.  

Here, using a genetic labeling method in adult mice, we found that continuous neurogenesis results in the replacement of the majority of granule neurons in the olfactory bulb and a substantial addition of granule neurons to the hippocampal dentate gyrus. Genetic ablation of newly formed neurons in adult mice led to a gradual decrease in the number of granule cells in the olfactory bulb, inhibition of increases in the granule cell number in the dentate gyrus and impairment of behaviors in contextual and spatial memory, which are known to depend on hippocampus. These results suggest that continuous neurogenesis is required for the maintenance and reorganization of the whole interneuron system in the olfactory bulb, the modulation and refinement of the existing neuronal circuits in the dentate gyrus and the normal behaviors involved in hippocampal-dependent memory..  

Here, we show that the anti-tumor effect of NPCs is age-dependently controlled by cell proliferation in the subventricular zone (SVZ) and that NPCs accumulating at a glioblastoma are diverted from their normal migratory path to the olfactory bulb.  

Odor coding in mammals is widely believed to involve synchronized gamma frequency (30-70 Hz) oscillations in the first processing structure, the olfactory bulb.  

Moreover, the insulin binding capacity of OM was quite high compared to that of olfactory bulb or liver.  

Noradrenergic projections from the locus coeruleus (LC) project to the olfactory bulb (OB), a cortical structure implicated in odor learning and perceptual differentiation among similar odorants.  

PRINCIPAL FINDINGS: Here we describe a Cre-transgenic line that allows reproducible expression of transgenic proteins of choice in a small number of neurons of the adult cortex, hippocampus, striatum, olfactory bulb, subiculum, hypothalamus, superior colliculus and amygdala.  

We analyzed the gene expression of regionally defined GABAergic neurons from the cortex, olfactory bulb, striatum, and cerebellum of glutamate decarboxylase 67-green fluorescence protein (GAD67-GFP) knock-in mice.  

The mouse olfactory bulb is richly innervated by zinc-enriched terminals. Here, the plasticity of the zincergic system was studied in the olfactory bulb of the Purkinje Cell Degeneration mutant mouse, an animal with specific postnatal neurodegeneration of the main projection neurons of the olfactory bulb. The analysis focused particularly on the anterior olfactory nucleus since most centrifugal afferents coming to the olfactory bulb arise from this structure. Zinc-enriched terminals in the olfactory bulb and zinc-enriched somata in the anterior olfactory nucleus were visualized after selenite injections. Immunohistochemistry against the vesicular zinc transporter was also carried out to confirm the distribution pattern of zinc-enriched terminals in the olfactory bulb. The mutant mice showed a clear reorganization of zincergic centrifugal projections from the anterior olfactory nucleus to the olfactory bulb. First, all zincergic contralateral neurons projecting to the olfactory bulb were absent in the mutant mice. Since no noticeable changes were observed in the zinc-enriched terminals in the olfactory bulb, it is conceivable that mitral cell loss could induce a reorganization of zinc-enriched projections coming from the anterior olfactory nucleus, probably directed at balancing the global zincergic centrifugal modulation. These results show that zincergic anterior olfactory nucleus cells projecting to the olfactory bulb undergo plastic changes to adapt to the loss of mitral cells in the olfactory bulb of Purkinje Cell Degeneration mutant mice..  

In the second part the NPY Y(1) and Y(2) receptors were studied in the subventricular zone, the rostral migratory stream, and the olfactory bulb in normal mice and mice with genetically deleted NPY Y(1) or Y(2) receptors. Mice deficient in the Y(1) or Y(2) receptor had fewer proliferating precursor cells and neuroblasts in the subventricular zone and rostral migratory stream and fewer neurons in the olfactory bulb expressing calbindin, calretinin or tyrosine hydroxylase.  

Unexpectedly, in transgenic fish produced by both integration of linearized plasmid or Tol2-mediated transgenesis, sCMV promoter expression was generally observed in a small population of cells in telencephalon and spinal cord between days 2 and 7, and was thereafter confined to discrete regions of CNS that included the olfactory bulb, retina, cerebellum, spinal cord, and lateral line.  

Many of the animal models designed to study the migration of these cells from the ventricle to places of interest like the olfactory bulb or an injury site require histology to localize precursor cells. The precursors migrating from the SVZ along the RMS were found to populate the olfactory bulb with all three types of neural cells; neurons, oligodendrocytes, and astrocytes. In all cases 10-30% of these cells were labeled in the RMS en route to the olfactory bulb. Ara-C an anti-mitotic agent eliminated precursor cells at the SVZ, RMS, and olfactory bulb and also eliminated the MRI detection of the precursors.  

Forebrain subventricular zone (SVZ) progenitor cells give rise to glia and olfactory bulb interneurons during early postnatal life in rats. However, the transplanted interneurons lost the expression of the olfactory bulb transcription factors Tbr2 and Dlx1, and acquired a cerebellar-like morphology.  

These newly generated cells migrate from the subventricular zone along the rostral migratory stream and differentiate into mature olfactory bulb neurons throughout adulthood. We conclude that in R6/2 mice, progenitor cells have an impaired migration in their route to the olfactory bulb, with accumulation of cells in the caudal rostral migratory stream that does not result from changes in PSA-NCAM expression and/or cell death..  

Neural stem cells (NSCs) in the subventricular zone (SVZ) continuously generate olfactory bulb interneurons in the adult rodent brain.  

In a separate group of mice, alpha-synuclein immunoreactivity was assessed in the olfactory bulb. Thy1-aSyn mice also displayed proteinase K-resistant alpha-synuclein inclusions throughout the olfactory bulb.  

In the rat main olfactory bulb (MOB), GABAergic granule and periglomerular cells innervate mitral and tufted cells, but the source of their own inhibition remains elusive.  

Previous studies have revealed that this region is a source of cells that will populate both the olfactory bulb and basal telencephalic limbic system.  

Postmortem examination revealed marked swelling of right cerebral hemisphere and olfactory bulb.  

CONTEXT: Physiological activation of the prokineticin pathway has a critical role in olfactory bulb morphogenesis and GnRH secretion in mice.  

An unusual property of the olfactory system is that sensory input at the level of the first synapse in the olfactory bulb takes place at two mirror-image glomerular maps that appear identical across the axis of symmetry. Thus, while mirror odor maps show symmetry at the macroscopic level in maps encompassing the entire surface of the olfactory bulb, they display asymmetry at the level of the single glomerulus..  

To elucidate compositional changes of the olfactory bulb and tract with aging, the authors investigated age-related changes of elements in the olfactory bulbs and tracts of Japanese and the relationships among the elements. After ordinary dissection at Nara Medical University was finished, the olfactory bulbs were resected with the olfactory tracts from 40 subjects. After ashing with nitric acid and perchloric acid, element contents in the olfactory bulbs and tracts were analyzed by inductively coupled plasma-atomic emission spectrometry. Seven elements of Ca, P, S, Mg, Zn, Fe, and Na did not change significantly in the olfactory bulbs and tracts with aging. The Ca, P, and S contents of major elements were less than 10 mg/g in all of the olfactory bulbs and tracts. Regarding the relationships among the elements, extremely or very significant direct correlations were found among the contents of Ca, P, Mg, Zn, and Na in the olfactory bulbs and tracts, with one exception. As P increased in the olfactory bulb and tract, Ca, Mg, Zn, Na, and S also increased in the olfactory bulb and tract..  

The generated neuroblasts migrate to their appropriate location and differentiate to mature granule cells and olfactory bulb interneurons, respectively.  

METHODS: We made use of MTT, BrdU and TUNEL assays to testify the biologic impact of nanosize TiO2 on olfactory bulb neurons cultured in vitro. RESULTS: In this article, we elucidate the cytotoxicity of titanium dioxide to olfactory bulb neurons on cellular and molecular level.  

We removed the brains, measured the length of the olfactory bulbs, and counted BrdU-labelled cells in the main and accessory olfactory bulbs (MOB, AOB), lateral cortex (LC) and nucleus sphericus (NS). Additionally, males produce more new cells than females in the olfactory bulbs, LC and NS.  

However, it remains unclear whether GFP and the commonly used progenitor markers label different cell populations in the neurogenic subventricular zone (SVZ) and its rostral extension into the olfactory bulb (i.e.  

Using high-performance liquid chromatography, dopamine (DA), serotonin (5HT), noradrenaline (NA) and their metabolites were then measured in samples of striatum versus olfactory bulbs as controls. In the olfactory bulb, exogenous levodopa caused increased DA levels and increased DA-, 5HT- and NA-turnover rates, but decreased 5HT and NA levels, regardless of animal activity.  

Brain lesion studies suggest that the putative control system is located along an axis that connects the olfactory bulb and the enthorhinal cortex (enthorhinal-hippocampal-septal-prefrontal cortex-olfactory bulb axis).  

This Cre-expressing line also significantly spares the main olfactory bulb reducing the potential confound of an olfactory deficit.  

Brain transfer rate (BTR) and brain to plasma concentration ratio (BPCR) of radiolabelled human serum albumin injected intravenously were calculated to evaluate the brain transfer of serum albumin in the cerebral cortex, the right hemi-brain and the olfactory bulb of senescence accelerated prone mice (SAMP8) and senescence accelerated resistant mice (SAMR1). BTR and BPCR in SAMP8 and SAMR1 were significantly higher in the olfactory bulb than in the cerebral cortex or the right hemi-brain. Age-related significant changes in BTR and BPCR were observed in the olfactory bulb of SAMP8 and SAMR1. These findings suggest that the barrier function to serum albumin in the olfactory bulb of SAMP8 and SAMR1 is not so tight as it is in the cerebral cortex and becomes weaker with age and that the age-related changes are manifested at a younger age in SAMP8 than in SAMR1..  

This real time PCR analysis showed high Eag1 expression in the olfactory bulb, cerebral cortex, hippocampus, hypothalamus, and cerebellum.  

Here we report that shortly after mating, a surge in dopamine in the mouse main olfactory bulb impairs the perception of social odors contained in male urine. These results show that an active sensory barrier blocks social olfactory cues detrimental to pregnancy, consistent with the main olfactory bulb being a major relay through which social odor modulates reproductive status..  

Mitral and tufted cells are the 2 types of output neurons of the main olfactory bulb. To examine this possibility, we compared the odor-evoked responses of identified single units recorded in the mitral cell layer (MCL units), in the core of the external plexiform layer (not at the glomerular border tufted cells), or at the glomerular border of this layer (GB tufted cells) of the entire olfactory bulb. The projection-type tufted cells situated closer to the entrance of the olfactory bulb may thus form a distinct physiological class of output neurons and differ from mitral cells and other tufted cells in the manner of processing olfactory information..  

NR2C-containing NMDA receptors are most abundant in cerebellum, thalamus and olfactory bulb, and are also expressed in oligodendrocytes and hippocampal interneurons.  

The spontaneous activity and impulse conduction velocities of mitral and tufted cells were compared in the entire main olfactory bulb of freely breathing, anesthetized rats.  

The accessory olfactory bulb (AOB) in the adult rat is organized into external (ECL) and internal (ICL) cellular layers separated by the lateral olfactory tract (LOT). MACs and INBs share inputs from fiber efferents arising in the main olfactory bulb (MOB) and AOB and send axons to IGCs.  

The subventricular zone (SVZ) of the lateral ventricle contains neural stem and progenitor cells that generate neuroblasts, which migrate to the olfactory bulb where they differentiate into interneurons.  

We also show that it is not the estimated proportion of potentially functional OR genes, but rather the estimated total number of OR genes that correlates positively with relative olfactory bulb size, an anatomical correlate of olfactory capability.  

The piriform cortex (PC) is the primary terminal zone of projections from the olfactory bulb, termed the lateral olfactory tract (LOT).  

This study demonstrates that administering rats either cocaine or a selective serotonin (or 5-hydroxytryptamine; 5-HT) reuptake inhibitor (SSRI) for 16 weeks results in reduced density of dopaminergic and noradrenergic terminals in the striatum and olfactory bulb, respectively, reflecting pruning of the terminal arbor of ventral midbrain dopaminergic and locus coeruleus noradrenergic neurones.  

Adult neurogenesis occurs in the hippocampus and the olfactory bulb of the mammalian CNS.  

In this study we examined the role of apoE on the rate of synaptic recovery in the olfactory bulb (OB) following olfactory epithelium (OE) lesioning in mice.  

Furthermore, in situ hybridization showed that E-dlg was mostly expressed in olfactory bulb and cerebellum..  

The mechanisms orienting the migration of neuroblasts from the SVZ to the olfactory bulb (OB) via the rostral migratory stream (RMS) have been extensively studied, but factors controlling neuroblast exit from the SVZ remain poorly explored.  

gamma-Aminobutyric acid (GABA)ergic synapses are thought to play pivotal roles in the processing of activity patterns in the olfactory bulb (OB), but their functions have been difficult to study during odor responses in the intact system.  

Further neuronal structures expressing CXCR7 comprised the olfactory bulb, accumbens shell, supraoptic and ventromedial hypothalamic nuclei, medial thalamus, and brain stem motor nuclei.  

Olfactory sensory neurons (OSN) in mice express only 1 of a possible 1,100 odor receptors (OR) and axons from OSNs expressing the same odor receptor converge into approximately 2 of the 1,800 glomeruli in each olfactory bulb (OB) in mice; this yields a convergence ratio that approximates 2:1, 2 glomeruli/OR.  

Although this process is well documented in the hippocampus and olfactory bulb, the possibility of neuron formation in other brain regions is under vigorous debate.  

We tested the candidate reference genes in mouse whole brain, cerebellum, brain stem, hippocampus, medial septum, frontal neocortex, and olfactory bulb.  

In adult rodents, subventricular zone (SVZ) astrocytes (B cells) function as primary progenitors in the generation of new neurons that migrate to the olfactory bulb (OB), where they differentiate into multiple types of interneurons.  

The subventricular zone-olfactory bulb pathway is one of the preferred model systems by which to study neural stem cell proliferation, migration, and differentiation in adult rodent brain. We show that bioluminescence imaging (BLI) allows quantitative follow-up of the migration of adult neural stem cells into the olfactory bulb in time.  

Magnetic resonance imaging showed olfactory bulb absence.  

In order to emphasize similarities and differences of these two structurally related molecules, null mutants for CHL1 and NrCAM were directly compared with respect to axonal guidance in the hippocampus and the olfactory bulb and the sizes of the ventricular system and the cerebellar vermis using a combined structural magnetic resonance imaging (MRI) and histological approach.  

The expression of OMP was decreased significantly in the olfactory bulbs of anosmia groups but there were no differences between the anosmia treatment groups.  

In the olfactory bulb (OB) glomeruli, numerous synapses must form between sensory olfactory neurons and the dendrites of mitral/tufted and periglomerular cells.  

Brain activation following repeated presentation of the same odor - as indexed by c-Fos expression - also habituated in accessory olfactory regions (mitral and granular layers of the posterior accessory olfactory bulb and posteroventral medial amygdala), as well as regions involved in defensive behavior, including the ventromedial and dorsal premammillary hypothalamic nuclei, basolateral amygdala and periaqueductal grey.  

We demonstrate that vomeronasal axons in the DMD-null mice are defasciculated, and some of the defasciculated vomeronasal axons aberrantly entered into the main olfactory bulb, which indicates that the product(s) of the DMD gene plays an important role in vomeronasal nerve organization.  

By adulthood, Wif1 is mainly expressed in the medial habenular nucleus (MHb) in the epithalamus, the mitral layer cells in the olfactory bulb and a few nuclei in the hypothalamus.  

Ascl1 lineage cells contribute to distinct cell types in each major brain division: the forebrain including the cerebral cortex, olfactory bulb, hippocampus, striatum, hypothalamus, and thalamic nuclei, the midbrain including superior and inferior colliculi, and the hindbrain including Purkinje and deep cerebellar nuclei cells and cells in the trigeminal sensory system.  

In addition, TROY mRNA was expressed in the developing olfactory bulb from embryonic day (E) 13.5 to neonate. Next, we focused on the detailed cellular characterization of TROY-expressing cells in the developing olfactory system.TROYmRNAwas first detected in the olfactory nerve layer (ONL) of the olfactory bulb at E13.5 and was expressed most intensely in the inner ONL (ONL-i) during late embryogenesis. In the postnatal olfactory bulb, TROY-expressing cells were also detected in the glomerular layer (GL) and ONL-i. Thus, TROY was expressed in some specific subsets of glial cells in the olfactory bulb, including OECs, and may play some roles in the developing and adult olfactory system..  

In most of the regions YY1 is not very abundant, but in the olfactory bulb, cerebellar cortex, hippocampus, cerebral cortex, wall of the lateral ventricle and rostral migratory stream intense YY1 staining is observed.  

In this study, we compared the depression-like symptoms induced by olfactory bulbectomy (OBX) in the two inbred Wistar and Long Evans rat strains. We also analyzed the self-regulated oral intake of nicotine in these strains and the effect of nicotine on the depression-like symptoms of olfactory bulbectomy.  

The in situ hybridization data are consistent with NBCe1-B and -C, but not -A, being the predominant NBCe1 variants in brain, particularly in the cerebellum, hippocampus, piriform cortex, and olfactory bulb.  

Whether the change in dopamine in the olfactory bulb contributes equally to hyposmia in male and female Parkinson's patients is the subject of the present study. In a stereological study the total number of tyrosine hydroxylase immunoreactive neurons in the olfactory bulbs of male and female Parkinson's patients and age-matched controls has been estimated. The number of dopaminergic cells in the olfactory bulbs of both male and female Parkinson's patients equals that of healthy males of the same age group. We therefore conclude that the hyposmia in Parkinson's disease patients cannot simply be ascribed to dopamine in the olfactory bulb..  

In this review, we discuss several proposed models for mixture processing, along with experimental data gathered from both the initial stage of olfactory processing (i.e., antennal lobe in insects or olfactory bulb in vertebrates) and higher areas of the brain, with an emphasis on how the lateral circuits in the antennal lobe or olfactory bulb may contribute to mixture processing.  

The anterior PC (APC) receives a strong ascending input from the olfactory bulb, carrying information regarding olfactory cues in the environment.  

These local pathways initiated by glutamate account for a large part of the coupling between synaptic activity and functional hyperemia in the olfactory bulb..  

The area under curve (AUC) of cerebrum, cerebellum and olfactory bulb increased by 1.16, 0.77 and 3.34 times, with 2.66.  

In the adult brain, neuroblasts originating in the subventricular zone migrate through the rostral migratory stream to the olfactory bulb.  

Thus, ECM molecules are present in dynamic spatio-temporal positions to affect OSN axons as they navigate to the olfactory bulb and establish synapses..  

In the postnatal subventricular zone (SVZ), neuroblasts migrate in chains along the lateral ventricle towards the olfactory bulb.  

The effort of the present study was to map NPP gene expression pattern in olfactory bulb, hippocampus, cerebral cortex, striatum, and cerebellum at crucial ages for rat development (7, 14, 21, 60, and 150 days old) by a semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) strategy. The relative expression of NPP3 decreased during the aging mainly on cerebellum, hippocampus, and olfactory bulb.  

There is a marked rostral to caudal gradient of the density of this binding site from the olfactory bulbs to the cervical spinal cord, with a consistent binding affinity, K(d) approximately 1-3 nM. The olfactory nerve layer of the olfactory bulb has the highest binding site density.  

Distinct olfactory bulb (OB) interneurons are thought to become specified depending on from which of the different subregions lining the lateral ventricle wall they originate, but the role of region-specific transcription factors (TFs) in the generation of OB interneurons diversity is still poorly understood.  

The first reorganization of odor representations in the nervous system occurs at the synapse between olfactory receptor neurons and second-order neurons in olfactory bulb glomeruli.  

The effects on proliferation were mirrored in changes in the number of neuroblasts migrating from the SVZ to the olfactory bulb (OB).  

CONTEXT: Mice deficient in prokineticin 2(PROK2) and prokineticin receptor2 (PROKR2) exhibit variable olfactory bulb dysgenesis and GnRH neuronal migration defects reminiscent of human GnRH deficiency.  

OBJECTIVE: To investigate changes of olfactory bulb (OB) volume over time in relation to olfactory function. olfactory bulb volume was determined using magnetic resonance imaging.  

In the olfactory bulbs, where the uptake of radioactivity was higher than in the rest of the brain, PK11195 and Ro 5-4864 were able to significantly inhibit [ (18)F] 12, while little or no pharmacological action of these established PBR drugs were observed on the uptake of [ (18)F] 8, [ (18)F] 15, and [ (18)F] 18 compared to control animals.  

The olfactory bulb (OB) is considered to be the most important relay station in odor processing.  

While the expression levels of Bach1 mRNA in the olfactory bulb were significantly higher than other brain areas, those at the cortex showed the lowest activity.  

In addition, the c-Fos, GFAP, and nNOS levels in the hippocampus and the nNOS levels in the olfactory bulb increased. In contrast, pretreatment with MP before OVA exposure decreased the protein expression of c-Fos in the CA1 area, GFAP in NTS, and nNOS in CA1 and olfactory bulb, and while it increased the nNOS content in the NTS.  

To compare the in vivo migratory properties of OECs and SCs and evaluate the potential of migrating cells to participate in subsequent repair, we first transplanted freshly isolated GFP-expressing adult rat olfactory bulb-derived OECs and SCs into normal and X-irradiated spinal cords.  

Expression of calbindin and Pax6, indicative for other lineages of olfactory bulb interneurons, were not affected. In conclusion, these data reveal that polySia controls instructive NCAM signals, which direct the differentiation of subventricular zone-derived precursors towards the calretinin-positive phenotype of olfactory bulb interneurons..  

In the present study, we analysed transcript levels of the ligand Norrin (Ndph) and its two receptors Frizzled-4 (Fzd4) and LDL-related protein receptor 5 (Lrp5) in six different brain regions (cerebellum, cortex, hippocampus, olfactory bulb, pituitary and brain stem) of 6- to 8-month-old wild-type and Ndph knockout mice by quantitative real-time PCR.  

Olfactory sensory neurons (OSNs) send their axons to distinct glomeruli in the olfactory bulb. Cocultures with forebrain explants revealed that tissue from the presumptive olfactory bulb of embryonic stage E14 exhibited nonpermissive, repellent effects on outgrowing neurites, whereas precultured bulb tissue strongly attracted them, even from distantly located OE explants.  

In the present study, we sought to determine if toxic doses of the drug can also induce pathological changes in the mouse olfactory bulb. This dose of the drug also induced substantial increases in the number of terminal deoxynucleotidyl transferase-mediated deoxyribonucleotide triphosphate (dNTP) nick end labeling (TUNEL)-positive cells in the olfactory bulb indicative of elevated DNA fragmentation. These results show that the toxic effects of amphetamine involve the olfactory bulb in addition to the striatum.  

OBJECTIVE: Gene-targeted deletion of the voltage-gated potassium channel, Kv1.3, results in 'super-smeller' mice that have altered firing patterns of mitral cells in the olfactory bulb, modified axonal targeting to glomerular synaptic units, and behaviorally have an increased ability to detect and discriminate odors.  

By postnatal day 7, strong mRNA expression was seen in the cerebellum, hippocampus and olfactory bulb, with diffuse cortical expression.  

It comprises sensory neurons in the epithelium of the vomeronasal organ, whose axons form the vomeronasal nerve projecting to the accessory olfactory bulb (AOB), which in turn projects to the vomeronasal amygdala through the accessory olfactory tract. The AOB exhibits the characteristic lamination of olfactory bulbs, except that it displays a mixed periglomerular and mitral somata layer superficially.  

We have shown that following olfactory nerve injury in mice, thallium-201 (201 Tl) transport from the nasal cavity to the olfactory bulb decreases. 201 Tl transport was measured as the ratio of radioactivity in the nasal cavity and olfactory bulb with gamma spectrometry.  

The olfactory bulbectomized (OBX) rat is an extensively investigated animal model of depression. In the present study the effects of olfactory bulbectomy in drug-naive adult male Sprague-Dawley rats (200-240 g) on global (gCGU) and regional cerebral glucose (rCGU) utilization was evaluated. The pattern of changes in the rCGU following OBX does not completely correlate with the pattern of connectivity of the olfactory bulbs, however, many regions with direct connection to the olfactory bulbs (e.g., amygdala, hypothalamus, ventral hippocampus, and ventral tegmental area) were found to be important for differentiation.  

This is in contrast to standard theoretical and experimental models of interneuron network gamma oscillations (ING), where frequency tightly depends on inhibition strength, but it is similar to observations made in some in vitro preparations in the hippocampus and the olfactory bulb and in some detailed network models.  

The olfactory bulb is one of the few structures in the mammalian forebrain in which continuous neurogenesis takes place throughout life. Neuronal precursors originate from progenitors located in the subventricular zone (SVZ) of the lateral ventricles, move tangentially in chains through the rostral migratory stream (RMS), and reach the olfactory bulb (OB), where they finally differentiate into granule and glomerular interneurons.  

Precursor cells in the SVZ migrate via the rostral migratory stream to the olfactory bulb where they differentiate into neurons.  

C-RFaimmunoreactive perikarya were observed in the olfactory bulb, the area ventralis telencephali pars dorsalis and lateralis, nucleus preopticus, nucleus preopticus periventricularis, nucleus lateralis tuberis pars posterioris, nucleus posterioris periventricularis, nucleus ventromedialis thalami, nucleus posterioris thalami, nucleus anterior tuberis, the oculomotor nucleus, nucleus reticularis superior and inferior, facial lobe, and vagal lobe. C-RFa immunoreactive fibers and nerve endings were present in the olfactory bulb, olfactory tract, area dorsalis telencephali pars centralis and medialis, area ventralis telencephali, midbrain tegmentum, diencephalon, medulla oblongata and pituitary.  

Ndrg2 was expressed in different regions of the brain, including the cerebral cortex, olfactory bulb, midbrain, hippocampus, and thalamus, with high levels in the midbrain and thalamus.  

Neuroblasts generated in the SVZ migrate in chains rostrally toward the olfactory bulb (OB), where they are differentiated into olfactory interneurons.  

Recent studies have also begun to reveal essential extrinsic and intrinsic molecular mechanisms that govern sequential steps of adult neurogenesis in the hippocampus and subventricular zone/olfactory bulb, from proliferation and fate specification of neural progenitors to maturation, navigation, and synaptic integration of the neuronal progeny.  

Neuropsin (kallikrein-related peptidase 8) is concentrated in the hippocampus, amygdala, olfactory bulb, and prefrontal cortex.  

Results from numerous studies have demonstrated that (1) nerve regeneration is severely delayed in apoE-gene knockout (KO) mice as compared to wild-type (WT) littermates; (2) 17beta estradiol replacement in ovariectomized mice resulted in a significant increase in levels of apoE and LRP, in the olfactory bulb (OB) and other brain areas; (3) estradiol treatment increased both apoE and neurite outgrowth in cortical and olfactory neuronal cultures; and (4) estradiol treatment had no effect on neurite outgrowth in cultures deprived of apoE or in the presence of apoE4.  

The various DHA levels were from 5.0% to 15.6% of total fatty acids in hippocampus, 3.9% to 13.7% in visual cortex, and 5.3% to 14.4% in olfactory bulbs. The expression of the cytoskeleton markers tyrosine tubulin, acetylated tubulin, and beta-actin in the hippocampus, visual cortex and olfactory bulb was not affected by brain DHA levels..  

Progenitor cells generated in the subventricular zone (SVZ) migrate toward the olfactory bulb (OB), where they differentiate into neurons.  

It is turned "off" by a rise in free Ca (2+) from nanomolar to the semicromolar range in the photoreceptor outer segments and the olfactory bulb neurons; by a similar rise in the bipolar and ganglion retinal neurons it is turned "on".  

Ongoing neurogenesis via the SVZ-rostral migratory stream pathway maintains neuronal replacement in the olfactory bulb (OB) throughout life.  

Cerebellum, apical hyperpallium, tegmentum and olfactory bulb are significantly reduced in CR.  

In addition, the olfactory system has several unique features that are useful for the study of nervous system function and development, including a large multigene family for olfactory receptor expression, peripheral neurons that regenerate, and a complex system for sensory innervation of the olfactory bulb. We focused on physiological, anatomical and behavioral approaches to study the chick olfactory neurons and the olfactory bulb. Since information from these neurons is initially processed in the olfactory bulb, we also conducted preliminary studies on the developmental timeline of this structure and showed that glomerular structures are organized in ovo during a critical time period, during which embryonic chicks can form behavioral associations with odorants introduced in ovo.  

Olfactory sensory neurons expressing a common receptor gene converge onto one or a few glomeruli with stereotyped positions within the mouse main olfactory bulb (MOB), producing a map of approximately 1800 olfactory columns representing approximately 1000 odorant receptors.  

In mammals, olfactory sensory neurons project their axons exclusively to the ipsilateral olfactory bulb.  

Odorants induce specific modulation of mitral/tufted (MT) cells' firing rate in the mammalian olfactory bulb (OB), inducing temporal patterns of neuronal discharge embedded in an oscillatory local field potential (LFP).  

In the postnatal mouse brain, we detected CCM3/PDCD10 expression in the olfactory bulb, neocortex, striatum, septal nuclei, hippocampus, dentate gyrus, thalamic and hypothalamic nuclei, inferior colliculus, Purkinje and granule cell layers and deep nuclei of the cerebellum, and in many cells and nuclei in the medulla.  

Herein, we use these mice to show that virus enters the brain primarily via the olfactory bulb, and infection results in rapid, transneuronal spread to connected areas of the brain.  

However, previous reports of BDNF mRNA and protein expression in olfactory epithelium and olfactory bulb (OB) have been inconsistent, raising questions on the proposed roles for BDNF.  

The main changes with FS occurred in the hippocampus, a region involved in memory, the insular cortex, a region involved with interoception (perception of internal sensations), the medial thalamus (region involved in alertness) and in regions involved with sensory perception (olfactory bulb, olfactory nucleus, occipital cortex, superior colliculus and parietal cortex), which corroborates their relevance in the perception of food..  

5alpha-RI and 3alpha-HSD are co-expressed in cortical, hippocampal, and olfactory bulb glutamatergic neurons and in output neurons of the amygdala, thalamus, cerebellum, and striatum.  

Several lines of evidence indicate that the neural changes underlying this memory occur in the accessory olfactory bulb (AOB) at the first stage of the vomeronasal system.  

In addition, chronic administration of mood stabilizers expanded the NSC pool in the adult brain, which subsequently increased the cell supply to the olfactory bulb.  

The production of adult-born neurons is an ongoing process accounting for > 10,000 immature neurons migrating to the olfactory bulb every day.  

The olfactory system and especially the olfactory bulb (OB) as the first relay in the olfactory system represent highly plastic structures.  

Rather, they displayed slower response termination and, consequently, reduced ability to transmit olfactory information to the olfactory bulb.  

Zinedin is primarily expressed in neurons of the hippocampus, cerebral cortex, olfactory bulb and caudate putamen nucleus.  

Furthermore, long-term habituation is an N-methyl-d-aspartate (NMDA) receptor-dependent process within the olfactory bulb.  

Large cells located in the primordial mitral cell layer were the first CR-ir neuronal population of the olfactory bulbs and were observed in 7-mm embryos. In later embryos and in alevins, CR-ir granule-like cells were observed in the olfactory bulbs. Comparisons of the terminal fields of primary olfactory fibers labeled with CR and with a more general olfactory marker in the olfactory bulbs of fry and adults revealed significant differences, with most glomeruli of the dorsomedial field receiving CR-negative olfactory fibers.  

Pdn/Pdn exhibits absence of the olfactory bulb, suggesting telencephalic dysmorphogenesis.  

Our previous studies indicate an increased expression of estrogen receptor (ER)-alpha and decreased growth factor synthesis in the olfactory bulb of reproductive senescent female rats as compared with young animals.  

Given the anatomical connectivity of the anterior olfactory nucleus and the amygdala, which receives axonal projections from the olfactory bulb, we hypothesized that there might be a relationship between tau and alpha-synuclein pathology in the olfactory bulb and the amygdala in AD. We screened for alpha-synuclein pathology in the olfactory bulb in AD with and without ALB, and investigated its relationship with tau pathology. In 38 of 41 (93%) AD/ALB cases and 4 of 21 (19%) AD cases without ALB (AD/non-ALB), alpha-synuclein pathology was detected in the olfactory bulb. Double immunolabeling at the light and electron microscopic levels revealed co-localization of tau and alpha-synuclein in the olfactory bulb neurons and neurites. The severity of tau pathology correlated with alpha-synuclein pathology in the olfactory bulb. In addition, alpha-synuclein pathology in the olfactory bulb correlated with alpha-synuclein pathology in amygdala. Tau pathology was greater in both the olfactory bulb and amygdala in AD/ALB than in AD/non-ALB, but there was no difference in tau pathology between the two groups in other brain regions assessed. The present study shows that in AD/ALB, the olfactory bulb is nearly equally vulnerable to tau and alpha-synuclein pathology as the amygdala and suggests that neurodegeneration in these two anatomical regions is linked..  

Cortex-derived cells proliferate faster in the subependyma and reach the olfactory bulb earlier than striatum-derived cells. In the olfactory bulb, cortex-derived cells produce more cells and more dopaminergic neurons in the glomerular layer than striatum-derived cells. Thus, history matters; cortex-derived neural stem cells in the subependyma give rise to progeny in the olfactory bulb and striatum but in different proportions than striatum-derived neural stem cells..  

We asked if activity within the first stage of olfactory processing, the glomerular layer of the olfactory bulb, predicts odor mixture perception. This suggests that spatial activity patterns within the olfactory bulb are not always sufficient to specify component recognition in mixtures..  

HSV-1 detection by quantitative polymerase chain reaction (qPCR), virus isolation and immunohistochemistry, magnetic resonance imaging, and histopathological examination verified dramatic encephalitis mainly in the brainstem, but also in the olfactory bulb and other segments of the brain of diseased rats.  

In addition to sites previously shown to express GnRH receptors such as the hippocampus, amygdala and the arcuate nucleus, the improved resolution afforded by immunocytochemistry detected cells in the mitral cell lay of the olfactory bulb as well as the central grey of the mesencephalon.  

In this study, we evaluated the gene expression profiles in the olfactory bulbs of normal rats and naris-occluded rats using the gene microarray technique. STUDY DESIGN AND METHODS: To induce atrophic change in the olfactory bulb, we performed a unilateral nasal obstruction by electronic cauterization on postnatal day 1 rats. CONCLUSION: This study examines candidate genes associated with the development, apoptosis, and signal transduction of the olfactory bulb.  

Hippocampus, olfactory bulb, and cerebellum (except NT-3) did not show substantial age- or genotype-related regulation of neurotrophins.  

bFGF levels were significantly raised in the olfactory bulb (OB) and striatum following intranasal administration.  

Mammalian SVZ progenitors continuously generate new neurons in the olfactory bulb.  

Previous data suggest that cyclic GMP (cGMP) signaling can play key roles in the circuitry of the olfactory bulb (OB).  

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