Electrical stimulation of mitral cell axons in the lateral olfactory tract (LOT) resulted in excitation of pyramidal cells (PCs), which was followed approximately 10 ms later by inhibition that was highly reproducible between trials in its onset time. 
Single units in the mitral cell body layer (MCL) and external plexiform layer (EPL) were identified by antidromic activation from the lateral olfactory tract (LOT), electrode track reconstructions based on dye marking, and the waveform of LOT-evoked field potentials.
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).
The piriform cortex (PC) is the primary terminal zone of projections from the olfactory bulb, termed the lateral olfactory tract (LOT).
To test this hypothesis, we analyzed the lateral olfactory tract-evoked field potential that represents the granule cell response to mitral cell activation and its plasticity in parasagittal slices of the AOB.
A typical example of the neurons that adopt this migration mode is guidepost neurons in the lateral olfactory tract designated as lot cells. These neurons are generated from the neocortical neuroepithelium and migrate tangentially down to the ventral edge of the neocortex abutting the ganglionic eminence, on which the future lateral olfactory tract develops.
The lateral olfactory tract is also very immature at birth with pioneer axons having penetrated only the most rostral portion of the piriform lobe.
The most extreme example was the nucleus of the lateral olfactory tract (LOT), which seemed to be devoid of double-labeled fibers despite high densities of 5-HT fibers and VGLUT3-positive fibers.
The vascular territory of the pampas fox middle cerebral artery included the lateral cerebral fossa, the lateral third of the olfactory trigone, the two rostral thirds of the piriform lobe, the lateral olfactory tract and most of the convex surface of the cerebral hemisphere, except for the more rostromedial areas of the frontal lobe bordering the endomarginal sulcus in the parietal and occipital lobes as well as the transverse fissure at the caudal pole of the cerebral hemisphere..
Semaphorin7A (Sema7A), the only glycosylphosphatidylinositol-anchored semaphorin, promotes axon growth in vitro and is required for the proper growth of the mouse lateral olfactory tract in vivo.
While both inputs clearly converge in areas classically considered olfactory-recipient (nucleus of the lateral olfactory tract, anterior cortical amygdaloid nucleus, and cortex-amygdala transition zone) or vomeronasal-recipient (ventral anterior amygdala, bed nucleus of the accessory olfactory tract, and anteroventral medial amygdaloid nucleus), segregation is virtually complete at posterior levels such as the posteromedial and posterolateral cortical amygdalae.
Volumetric measurements of the individual nuclei in the amygdala (CA) of the rabbit reveal poor development of the basolateral (BL) and lateral olfactory tract (NLOT) and medial (ME) nuclei.
The effect of adenosine on the fEPSP was examined in the lateral olfactory tract (Ia input) and associative tract (Ib input) of the rat piriform cortex.
Increased CRF immunoreactivity was also detected in swollen axons in subcortical white matter, caudate nucleus and lateral olfactory tract of the ipsilateral hemisphere, consistent with the failure of axonal transport.
Semaphorin 7A (Sema7A; also known as CD108), which is a glycosylphosphatidylinositol-anchored semaphorin, promotes axon outgrowth through beta1-integrin receptors and contributes to the formation of the lateral olfactory tract.
The development of olfactory bulb projections that form the lateral olfactory tract (LOT) is still poorly understood.
Field potentials were recorded from layer II of piriform cortex pyramidal cells following stimulation of the lateral olfactory tract.
Stimulation of the anterior dorsal thalamus generated a pattern of activity comparable to olfactory evoked potentials, but it became similar to stimulation of the optic nerve or brainstem after bilateral lesion of the lateral olfactory tract, which interrupted the antidromic activation of the olfactohabenular tract.
The OBLS is not able to pioneer the lateral olfactory tract (LOT) projection in vivo or when provided control (host) telencephalic territory in an in vitro assay.
In the nucleus of the lateral olfactory tract, the first layer contained only NADPHd-stained axons, in the second layer, there were numerous moderately stained cells, and in the third layer, a few but deeply stained neurons.
Stimulation of the lateral olfactory tract (LOT) produced a negative field potential in the EPL and a positivity in the GCL.
The axons of these cells projected to either the medial or the lateral olfactory tract and, in general, the location of the cell on the medial or lateral side of the bulb was indicative of the tract to which it would project.
All three agonists reduced the amplitude of the monosynaptic EPSPs generated by stimulation of the lateral olfactory tract (LOT) or of the association fiber pathway (ASSN).
Field potential laminar profiles were performed with multi-channel probes in the OB following stimulation of both the lateral olfactory tract (LOT) and the anterior piriform cortex (APC).
We imaged rats before and after lesion-induced disruption of the lateral olfactory tract to investigate the subsequent recovery and/or reorganization of functional neuronal circuitry.
Impressive enhanced cyclooxygenase-2 immunoreactivity was localized in anterior olfactory nucleus, tenia tecta, nucleus of the lateral olfactory tract, piriform cortex, lateral and basolateral amygdala, orbital frontal cortex, nucleus accumbens (shell) and associated areas of ventral striatum, entorhinal cortex, dentate gyrus granule cells and hilar neurons, hippocampal CA subfields and subiculum.
Much less is known about the development and connectivity of the lateral olfactory tract (LOT), which is formed by axons of M/T cells connecting the olfactory bulb to central neural regions.
lateral olfactory tract (LOT) synapses, formed by axons of olfactory bulb (OB) mitral cells and targeting piriform cortex (PC) pyramidal cells, ectopically express galanin in GalOE mice.
During the development of the OB, mitral cells migrate from the ventricular zone to the intermediate zone, where they begin to send axons along the lateral olfactory tract (LOT) to the cortical olfactory zones.
These neurons originate from the ventricular zone of the entire neocortex, tangentially migrate in the surface layer of the neocortex into the ventral direction, align in the future pathway of the lateral olfactory tract (LOT) and eventually guide the projection of LOT axons.
To functionally characterize the interlaminar synaptic EC circuit entrained the by hippocampal output, we performed simultaneous intracellular recordings and laminar profile analysis in the medial EC (m-EC) of the in vitro isolated guinea pig brain after polysynaptic hippocampal activation by lateral olfactory tract (LOT) stimulation.
Together with previous mRNA data, our observations suggest abundant axoplasmic transport and secretion in pathways such as the retino-collicular tract, the entorhino-hippocampal ('perforant') path, the lateral olfactory tract or the parallel fiber system of the cerebellum.
Immunohistochemical analysis of the rat brain shows a prominent localization of palmdelphin in the cerebral cortex, hippocampus, amygdala, septum, indusium griseum, piriform cortex, nucleus supraopticus, and nucleus of the lateral olfactory tract.
The characteristic features of guinea pig amygdala (CA), as shown by volumetric comparisons of the individual nuclei, are the poor development of the basolateral (BL) and lateral olfactory tract (NLOT) nuclei as well as the strong formation of the lateral (LA) and basomedial (BM) nuclei.
The highest density of 5-hydroxytryptamine immunoreactive fibers is observed in the central nucleus, the nucleus of the lateral olfactory tract, the paralaminar nucleus, the anterior amygdaloid area and a small region of the amygdalohippocampal area.
The entire amygdaloid complex was outlined and then further partitioned into five reliably defined subdivisions: 1) the lateral nucleus, 2) the basal nucleus, 3) the accessory basal nucleus, 4) the central nucleus, and 5) the remaining nuclei (including anterior cortical, anterior amygdaloid area, periamygdaloid cortex, medial, posterior cortical, nucleus of the lateral olfactory tract, amygdalohippocampal area, and intercalated nuclei).
However, mice expressed Tac2 mRNA neither in the hippocampus nor in the nucleus of the lateral olfactory tract, in contrast to rats.
We demonstrate that in BDNF+/- mice, lateral olfactory tract (LOT) synapses exhibit decreased release probability of glutamate, suggested by increased paired-pulse facilitation (PPF) of field excitatory postsynaptic potentials (fEPSPs), as well as by slower blocking rate of N-methyl-D-aspartate (NMDA) receptor-mediated excitatory postsynaptic currents (EPSCs) by MK-801 in the pyramidal neurons of the piriform cortex.
The nucleus of the lateral olfactory tract could not be definitively identified and the medial nucleus of amygdala appeared to be very small in the echidna.
We first report CGRP terminal fields in the olfactory-anterior septal region and also CGRP projections from the parabrachial nuclei to the olfactory-anterior septal region, the medial prefrontal cortex, the interstitial nucleus of the anterior commissure, the nucleus of the lateral olfactory tract, the anterior amygdaloid area, the posterolateral cortical amygdaloid nucleus, and the dorsolateral part of the lateral amygdaloid nucleus.
High densities of galanin-IR fibers were found in the axonal terminals of the lateral olfactory tract, hippocampal and presumably cerebellar mossy fiber system, in several thalamic and hypothalamic regions and the lower brain stem..
Maximal percentages of stimulation over basal levels were found in the anterior olfactory nucleus and in the lateral olfactory tract nucleus ( approximately 54%).
In addition, the EphA3 protein was also detected in various other structures, such as the lateral olfactory tract, anterior commissure, and corpus callosum, suggesting the possibility that EphA3 might regulate the formation of various neuronal networks in the developing brain, including the TC projection and the commissural fibers..
For example, granule cell-mediated inhibition following electrical stimulations to the lateral olfactory tract is robust during the first postnatal week, and then decreases abruptly after the second week.
There were significant differences between passive vs trained groups, but not regarding untrained rats, in the lateral olfactory tract, dentate gyrus, CA3 area, ventromedial hypothalamic, lateral hypothalamus, preoptic medial, frontal cortex (2), granular retrosplenial cortex (2), entorhinal cortex (1 and 2), piriform cortex, and substantia nigra.
Specifically, structures that were not previously considered to be developmentally linked, the nucleus of the lateral olfactory tract and the lateral, basolateral, and basomedial nuclei, all appear to have a common requirement for Pax6.
This study was carried out to investigate the transient ischemia-induced changes of neurofilament 200 kDa (NF-200) immunoreactivity and protein content in the gerbil lateral olfactory tract (LOT) after 5 min of transient forebrain ischemia.
The characteristic features of the common shrew amygdala (CA), as shown by volumetric comparisons of the individual nuclei, are the poor development of the lateral (LA) and basomedial (BM) nuclei as well as the particularly strong formation of the basolateral (BL) and lateral olfactory tract (NLOT) nuclei.
Odor-induced cortical activation, which primarily originated in layer II, appeared in a narrow band beneath the rhinal sulcus over the lateral olfactory tract, corresponding to the dorsal part of the anterior piriform cortex.
Significant transport of Mn2+ was observed in olfactory structures ipsilateral to site of Mn2+ administration including the bulb, lateral olfactory tract (lo) by 12 h and in the tubercle, piriform cortex, ventral pallidum, amygdala, and in smaller structures such as the anterior commissure after 24 h post-administration.
We therefore followed the postnatal localization of CNR/Pcdh alpha protein in major axonal tracts, such as the internal capsule, lateral olfactory tract, and optic nerve, and found that its axonal localization was dramatically lost in parallel with the increased expression of myelin markers.
We recently demonstrated that following repetitive stimulation of the lateral olfactory tract (LOT) at 2-8 Hz, a delayed response (onset at circa 60 ms) was evoked in the caudal portion of the EC, identified as medial EC, that does not receive a direct olfactory input.
High densities of galanin-IR fibers were found in the axonal terminals of the lateral olfactory tract, the hippocampal and presumably the cerebellar mossy fibers system, in several thalamic and hypothalamic regions and the lower brain stem.
During development, olfactory bulb axons navigate a complex microenvironment composed of myriad molecules to construct a bundle called the lateral olfactory tract. In the present study, we produced and characterized six monoclonal antibodies that label the lateral olfactory tract and its surroundings in a unique pattern. The labeling profiles suggested that the antigen molecules recognized by each antibody are heterogeneously distributed around the developing lateral olfactory tract. The systematic screening successfully identified specific cDNA clones for all of the monoclonal antibodies, which highly probably coded for the antigen molecules, and therefore unveiled the molecular nature of local components that embrace the developing lateral olfactory tract in mice..
The projection neurons in the olfactory bulb (mitral and tufted cells) send axons through the lateral olfactory tract (LOT) onto several structures of the olfactory cortex.
The results showed important connections with the main olfactory bulb, via the lateral olfactory tract.
In the present study we performed a detailed topographic analysis of both the early and the delayed entorhinal responses induced by patterned stimulation of the lateral olfactory tract in the isolated guinea pig brain.
Here, we show that in the absence of the LIM-homeodomain (LIM-HD) gene Lhx2, a particular amygdaloid nucleus, the nucleus of the lateral olfactory tract (nLOT), is selectively disrupted.
These cells expressed immunoreactivities to calretinin and the lot-1 antigen which has been shown to be involved in guidance of the developing lateral olfactory tract. These results suggest that, in the development of the stria terminalis, the axonal outgrowth is guided by a mechanism similar to that of the developing lateral olfactory tract, a major amygdalopetal connection..
Here we describe olfactory bulb axons chronologically arranged in the lateral olfactory tract. This special assembly of the axons explains the nontopographic relationships between the olfactory bulb and the lateral olfactory tract axons that have been described in previous studies and could possibly influence the subsequent selection of the olfactory target areas by these axons..
Fluoro-Jade staining following WDIA+H injury revealed damage to fibers in the optic tract, lateral olfactory tract, corpus callosum, anterior commissure, caudate-putamen, brain stem, and cerebellum.
As an initial step towards understanding the odor processing functions of these secondary olfactory structures, we recorded evoked field potentials in response to lateral olfactory tract stimulation in vivo in urethane-anesthetized Sprague-Dawley rats in the following brain structures: anterior olfactory nucleus, ventral and dorsal tenia tecta, olfactory tubercle, anterior and posterior piriform cortex, the anterior cortical nucleus of the amygdala, and lateral entorhinal cortex.
A group of rats was trained to discriminate between a patterned electrical stimulation of the lateral olfactory tract, used as an artificial cue, associated with a water reward, and a natural odor associated with a flash of light.
The efferent connections of the nucleus of the lateral olfactory tract (LOT) were examined in the rat with the Phaseolus vulgaris leucoagglutinin (PHA-L) technique.
lateral olfactory tract (LOT)-evoked responses were recorded in rat aPCX coronal slices.
Isolated perfusion of slices with medium containing "dysfunctins" led to irreversible suppression of the amplitude of individual components of focal potentials induced by electrical stimulation of the lateral olfactory tract.
The two oscillations were differently affected by surgical interruption of the lateral olfactory tract.
At postnatal day 5-6 (P5-P6), the first CNPase(+) profiles appeared in the dorsal lateral olfactory tract adjacent to the accessory OB (AOB), followed by rare cell bodies and processes in AOB internal plexiform layer at P7.
We performed an electrophysiological and imaging study of the propagation pattern of the olfactory input carried by the fibres that form the lateral olfactory tract (LOT) into the parahippocampal region of the in vitro isolated guinea pig preparation.
The labeled pathways include, among others, the lateral olfactory tract, the entorhinohippocampal (perforant) pathway, the retroflex bundle, and the stria terminalis.
We point out that the anatomical data suggest that the medial and lateral divisions of EC are separate, and recent studies of the propagation of signals originating in the lateral olfactory tract and perirhinal cortex to the EC [ J.
The nucleus of lateral olfactory tract showed moderate signal intensity; other parts of the forebrain, mesencephalon and brain stem only revealed a very weak level of CTGF mRNA expression.
The lateral olfactory tract extends into the basal telencephalon and its development is supported by the existence of pre-existing routes and several attractive or repulsive factors.
the lateral olfactory tract, olfactory and temporal limb of the anterior commissure, corpus callosum, stria terminalis, globus pallidus, fornix, mammillothalamic tract, solitary tract, and spinal tract of the trigeminal nerve.
Shock stimulation of afferent fibers (lateral olfactory tract) and association/commissural fibers evoked field potentials in aPCX that were analyzed across groups and between ages.
In all these experiments, animals were trained to discriminate among an artificial cue, a patterned electrical stimulation distributed to the lateral olfactory tract associated with a water reward, and a natural odor associated with a flash of light. Monosynaptic field potential responses evoked by single electrical stimuli to the lateral olfactory tract were recorded in the ipsilateral piriform cortex before and just after each training session. Monosynaptic field and polysynaptic field potentials evoked by single electrical stimuli applied respectively to the lateral perforant pathway and lateral olfactory tract were also recorded in ipsilateral dentate gyrus.
Mitral cells were stained retrogradely by tracer injection into the lateral olfactory tract and by local injection into the bulb.
The efferent projections of the marmoset bulb are organised entirely ipsilaterally and are established via a rudimentary medial olfactory tract and the dominant lateral olfactory tract.
The response pattern evoked by stimulation of the lateral olfactory tract was utilized to identify the lateral (l-EC) and medial (m-EC) entorhinal cortex.
Enhanced expression of HMGN3 was observed in the lateral olfactory tract, anterior commissure, corpus callosum, internal capsule, fornix, stria medullans, optic tract, and axon bundles.
The development of olfactory bulb projections that form the lateral olfactory tract (LOT) is still poorly understood.
WGA protein was further conveyed via the lateral olfactory tract to the olfactory cortical areas including the anterior olfactory nucleus, olfactory tubercle, piriform cortex and lateral entorhinal cortex.
In the rabbit the highest acetylcholinesterase activity is found in the basolateral nucleus and the nucleus of the lateral olfactory tract.
Using conditioned rats who had learnt to avoid repellent (cycloheximide) solution by olfaction, varying degrees of injuries were made to the lateral olfactory tract, a major central olfactory pathway connecting the olfactory bulb to the olfactory cortex.
A collection of 125 PHAL experiments in the rat has been analyzed to characterize the organization of projections from each amygdalar cell group (except the nucleus of the lateral olfactory tract) to the bed nuclei of the stria terminalis, which surround the crossing of the anterior commissure.
In preparations where only the secondary neurons of the lateral olfactory tract (LOT) were stained, the majority (76%) of sensory neurons had cell bodies in the intermediate layer of the olfactory epithelium.
Fish were divided in three groups: control fish, fish with only the lateral olfactory tracts (LOTs) intact and fish with the LOTs cut.
In agreement with this, TAG-1 protein was overexpressed in the major fibre tracts arising from these structures, including the corpus callosum, anterior and hippocampal commissures and lateral olfactory tract.
MHV OBLV has little direct effect on the olfactory epithelium, but causes extensive spongiotic degeneration and destruction of mitral cells and interneurons in the olfactory bulb such that the axonal projection from the bulb via the lateral olfactory tract is markedly reduced.
Therefore, to examine mGluR3-selective distribution, we used mGluR2-deficient mice as well as wild-type mice.Strong immunoreactivity for mGluR3 was found in the cerebral cortex, striatum, dentate gyrus of the hippocampus, olfactory tubercle, lateral septal nucleus, lateral and basolateral amygdaloid nuclei, and nucleus of the lateral olfactory tract.
Electrical stimulation at 200 Hz applied to the lateral olfactory tract provides a substitute for the normal background activity emanating from the bulb and enables the generation of oscillatory responses once again.
Properly set stimulation intensity of the lateral olfactory tract resets ISs exclusively (and not before) 4-10 s (5.6 +/- 2.0 s; mean +/- SD) after a preceding spontaneous spike.
Electrical stimulation of the lateral olfactory tract (5-6 stimuli at 10 Hz) that evoked granule cell feedback inhibition, blocked 60-100% of the odour-evoked [ Ca2+] transient in tufts when delivered within about 0.5 s of the odour.
In addition, Nr-CAM is found in crossing fiber pathways, including the anterior commissure, corpus callosum, and posterior commissure, and in nondecussating pathways, such as the lateral olfactory tract and the habenulointerpeduncular tract.
The radial cell migration in the LCS supplied cells to the ventro-lateral neocortex, pyriform cortex and to the level of the lateral olfactory tract.
The amygdalo-piriform transition area also projects moderately to other amygdaloid nuclei, including the parvicellular division of the basal nucleus, the anterior cortical nucleus, and the nucleus of the lateral olfactory tract.
During development, mitral cells, the major output neurons of the olfactory bulb, project their axons caudolaterally into the telencephalon and form the lateral olfactory tract (LOT).
Retrograde tracings revealed that tasseled cells, in addition to mitral/tufted cells, projected their axons to the lateral olfactory tract, indicating that there were two parallel projection systems in the shrew MOB, which might interact with each other via various types of gamma-aminobutyric acid (GABA)ergic interneurons.
Labeling was also found in extrahypothalamic structures such as the piriform cortex, the nucleus of the lateral olfactory tract, the central grey matter, the pars compacta of the substantia nigra, the dorsal raphe nucleus, the entorhinal cortex, the dentate gyrus and the Ammon's horn.
The content of neurons double-labeled for D1/D2 receptors was observed at in differing intensities in the dorsal endopiroform nucleus, the intercalated nucleus of amygdala, the anterior part of the cortical nucleus amygdala, the nucleus of the lateral olfactory tract, the piriform cortex, the parabrachial nucleus, the supraoptic nucleus and the parabigeminal nucleus.
In most of the regions inside the blood-brain barrier [ paraventricular nucleus (PVN), piriform cortex, lateral olfactory tract (LOT), and lateral preoptic area (LPO)], AT(1) receptor binding (sensitive to CV-11974) was significantly higher in TG compared with SD.
Cell and nuclear sizes of neurones in the supraoptic nucleus (SON), the nucleus of the lateral olfactory tract (LOT) and the medial habenular nucleus (MHB) were measured from neurones identified by in situ hybridization histochemistry for beta(III)-tubulin mRNA, and measurements were made from OT and AVP magnocellular neurones in the SON after phenotypic identification by immunohistochemistry.
Dye injections into the glomerular layer labeled the lateral olfactory tract. Vice versa, dye injections into the lateral olfactory tract made mitral cells and their glomerular branching patterns visible.
EPSPs were recorded extracellularly in response to lateral olfactory tract stimulation.
In addition, beta-netrin is expressed in a limited set of fiber tracts within the brain, including the lateral olfactory tract and the vomeronasal nerve.
Among the other brain tissue samples, significantly higher amount of radioactivity was detected in the lateral olfactory tract.
Stimulation of the olfactory bulb, lateral olfactory tract, piriform cortex, amygdala-entorhinal transition, lateral entorhinal cortex, or lateral perforant path (LPP) evoked an outer molecular layer sink (inferred distal dendritic excitation) in the dentate gyrus, with progressively decreasing onset latency.
The early-generated neurons designated as lot cells specifically mark the future site of the lateral olfactory tract (LOT) and guide LOT axons.
Twenty-four hours after cessation of such treatment with the higher dose (0.5 g/kg), the contents of dopamine (DA) and its metabolites were significantly reduced in the corpus striatum, hypothalamus, and lateral olfactory tract regions.
An exception was the nucleus of the lateral olfactory tract, which was poorly connected with the OfB.
We studied the contribution of the medial and lateral entorhinal areas to olfactory processing by analyzing the responses induced by lateral olfactory tract stimulation in different entorhinal subfields of the in vitro isolated guinea pig brain. Diffuse activation of the medial entorhinal region was also obtained by repetitive low-intensity stimulation of the lateral olfactory tract at 2-8 Hz.
We show that the activity of approximately 20% of neurons recorded in the horizontal limb of the diagonal band of Broca (HDB), which is the source of cholinergic projections to the olfactory system, can be modulated by electrical stimulation of either the lateral olfactory tract or the cell body layer of piriform cortex.
These results suggest that the receptor is present on the terminals of the lateral olfactory tract (LOT).
Crucian carp which had the medial bundle of the medial olfactory tract cut, leaving both the lateral bundle of the medial olfactory tract and the lateral olfactory tract intact, did not display any alarm reaction to skin extract; however, these fish reacted to exposure to L-alanine with feeding behaviour.
The lateral olfactory system (dorsolateral olfactory bulb glomeruli and lateral olfactory tract) and the external taste buds are probably specialized for food search and amino acid discrimination.
On PN30, brains were processed for anterograde horseradish peroxidase (HRP) labeling of lateral olfactory tract (LOT) fibers in anterior piriform cortex (aPCX) Layer Ia, Timm staining of association/commissural fibers in aPCX Layer Ib, or Golgi staining for reconstruction of aPCX semilunar cell dendrites.
Retrogradely labeled cells are found in insular, infralimbic, prelimbic, piriform, amygdalopiriform transition, entorhinal and perirhinal cortices, as well as in temporal field CA1 of Ammon horn and ventral subiculum, amygdala (nucleus of the lateral olfactory tract, anterior amygdaloid area, anterior cortical, posterolateral cortical, anterior and posterior basomedial, intercalated cells, basolateral and lateral nuclei), and extended amygdala, primarily in its central division.
IGL projections to the telencephalon are found in the horizontal limb of the diagonal band, olfactory tubercle, nucleus of the lateral olfactory tract, posterior bed nucleus of the stria terminalis, ventral pallidum, and in nuclei of the medial amygdala. A retinal projection is also visible in the lateral olfactory tract from which it extends rostrally, then medially along the base of the rhinal fissure.
Suppression of mitral/tufted cell single-unit spontaneous activity evoked by single lateral olfactory tract (LOT) shocks was examined during LOT stimulation at either 1 or 5 Hz (theta frequency).
GFRalpha-2 mRNA was highly expressed in many regions including olfactory bulb, lateral olfactory tract nucleus, neocortical layers IV and VI, septum, zona incerta, and arcuate and interpeduncular nuclei.
A group of rats was trained to discriminate between a patterned electrical stimulation of the lateral olfactory tract, used as an artificial cue associated with a water reward, and a natural odor associated with a light flash. Polysynaptic field potential responses, evoked by a single electrical stimulation of the same lateral olfactory tract electrode, were recorded in the molecular layer of the ipsilateral dentate gyrus prior to and just after each training session.
Two experiments were conducted using male Long-Evans rats with chronically implanted electrodes to assess the relative contribution to this potentiation of the two main fiber systems that interconnect the OB and PC: the lateral olfactory tract (LOT), which contains mitral cell axons that synapse on PC pyramidal cells, and the PC association fiber system, which consists of the axons of PC pyramidal cells that synapse on several cell populations within the PC and on granule cells in the OB.
Mitral cell loss was induced unilaterally by transection of their axons in the lateral olfactory tract in 18-day-old rats. The target field of postsynaptic neurons remaining after lateral olfactory tract transection is insufficient to maintain normal survival of all existing olfactory neurons.
By using in situ hybridization, cells expressing ORL1 mRNA were most numerous throughout multiple cortical regions, the anterior olfactory nucleus, lateral septum, endopiriform nucleus, ventral forebrain, multiple hypothalamic nuclei, nucleus of the lateral olfactory tract, medial amygdala, hippocampal formation, substantia nigra, ventral tegmental area, central gray, raphe complex, locus coeruleus, multiple brainstem motor nuclei, inferior olive, deep cerebellar nuclei, vestibular nuclear complex, nucleus of the solitary tract, reticular formation, dorsal root ganglia, and spinal cord.
Other retrogradely labeled neurons were observed in the taenia tecta, the septum, the nucleus of the lateral olfactory tract, the preoptic area, the lateral hypothalamic area, the mediobasal hypothalamus, the lateral part of the premammillary nucleus, the paraventricular nucleus of the hypothalamus, the paraventricular thalamic nucleus, the central grey, the substantia nigra (SN), the ventral tegmental area (VTA), the lateral nucleus to the interpeduncular nucleus (IIP), the raphe and the locus coeruleus (LC).
To establish this new technique, electrical field potentials evoked in the piriform and entorhinal cortices by lateral olfactory tract stimulation were correlated to the optical signal.
NDB stimulation increased the spontaneous firing rate of PC cells, and increased the disynaptic excitatory (B1) and decreased the disynaptic inhibitory (P2) FP components following lateral olfactory tract (LOT) stimulation.
A similar NMDA-receptor-dependent prolonged depolarization is elicited by stimulation of the lateral olfactory tract at current intensities subthreshold for antidromic activation of the recorded neuron.
Stimulation of the HDB caused an enhancement of the late, disynaptic component of the evoked potential elicited by stimulation of the lateral olfactory tract but caused a suppression of the synaptic potential elicited by stimulation of the posterior piriform cortex.
The expression patterns of sema A and sema IV in the developing olfactory system confirm that they may play a cooperative role in the formation of the lateral olfactory tract.
The present report describes neurosteroid modulation of olfactory bulb function by examining the effects of intrabulbar infusion of dehydroepiandrosterone sulfate (DHEAS), a neurohormone discovered in rat brain, on field potentials in the granule cell layer evoked by paired-pulse stimulation of the mouse lateral olfactory tract.
Scar tissue, formed after penetrating injuries to the lateral olfactory tract (LOT), cortex, perforant pathway, and spinal cord, contained numerous spindle-shaped cells expressing high levels of sema III mRNA.
This inhibition is not dependent upon chemosensory stimulation and may be mediated by olfactory bulb fibers projecting through the lateral olfactory tract to or through the olfactory tubercle.
During development, mitral cell axons, the major efferents of the olfactory bulb, exhibit a protracted waiting period in the lateral olfactory tract (LOT) before giving off collateral branches and innervating the target olfactory cortex.
Some of these enter the TV inducing the formation of the olfactory bulbs (OBs), whereas, mitral and tufted cell axons form the lateral olfactory tract (LOT).
Stimulation of the lateral olfactory tract also evoked field potentials in the AOB, which indicated antidromic activation of the mitral cells (period I and II) followed by activation of granule cells (period III).
After MC loss in the experimental animals there was a decrease in density of larger myelinated axons in the lateral olfactory tract (LOT).
After infusions of SeO3(2-) into combinations of cortical, medial, or amygdalohippocampal regions, retrogradely labeled zinc-containing somata were found in all amygdaloid nuclei except for the medial and central nuclei, the bed nucleus of the accessory olfactory tract, the nucleus of the lateral olfactory tract, and the anterior amygdaloid area.
Stimulation of afferent fibers in the lateral olfactory tract with theta-burst trains under control conditions potentiated the monosynaptic field excitatory postsynaptic potential (EPSP) by approximately the same extent (20.3 +/- 2%; n = 12) as reported for the slice.
The Vicia villosa and Erythrina cristagalli lectins were not specific for the vomeronasal system, since they labelled grey and white matters in structures including the lateral olfactory tract and the anterior olfactory nuclei.
During development, mitral cells, the main output neurons of the olfactory bulb, project axons into a very narrow part of the telencephalon and form an axonal bundle called the lateral olfactory tract (LOT).
The dorsal division projects to all divisions of the basal and accessory basal nuclei, to the periamygdaloid cortex, the nucleus of the lateral olfactory tract, the dorsal division of the amygdalohippocampal area, and the lateral capsular nuclei.
Responses of anterior piriform cortex layer II/III neurons to both odors and electrical stimulation of the lateral olfactory tract (LOT) were measured with intracellular recordings in urethan-anesthetized, freely breathing rats.
Moderate hybridization was observed in the periventricular hypothalamic nucleus, lateral hypothalamic area, medial mammillary nucleus, posterior hypothalamic nucleus, nucleus of the lateral olfactory tract, and within substantia nigra pars compacta.
Other sites of increased CRF-like immunoreactivity included the tenia tecta, inner layers of cingulate cortex, lateral septum, dorsal endopiriform nucleus, fundus striatum, and nucleus of the lateral olfactory tract.
After transection of the lateral olfactory tract, mGluR2/3-, mGluR7a-, and mGluR8-LI were reduced markedly in the target regions on the side ipsilateral to the transection; no significant changes were detected in mGluR1- or mGluR5-LI.
To clarify the action of noradrenergic inputs on the dendrodendritic interaction between mitral and granule cells in the rat olfactory bulb, we analyzed field potentials in the granule cell layer of the olfactory bulb evoked by paired-pulse stimulation of the lateral olfactory tract before and after the activation of the locus coeruleus.
Stimulation to the lateral olfactory tract and/or centrifugal fibers to the olfactory bulb evoked field excitatory postsynaptic potentials (fEPSPs) in the granule cells. In +/fynz mice tetanic stimulation to the lateral olfactory tract and/or centrifugal fibers induced N-methyl-D-aspartate (NMDA)-dependent long-term potentiation (LTP) of fEPSPs, whereas LTP was impaired in fynz/fynz mice.
The olfactory projection consists of three tracts: the lateral olfactory tract, which projects bilaterally to the lateral cortex and the rostral amygdala, crossing the midline through the stria medullaris-habenular commissure system; the intermediate olfactory tract, which projects ipsilaterally to the olfactory tubercle and contributes to the contralateral projection; and the medial olfactory tract, which projects ipsilaterally to the dorsomedial retrobulbar formation.
Immunofluorescence was used to double label for IP3R and for gamma-aminobutyric acid (GABA) or for projection neurons, which were retrogradely labeled following dextran injection into the lateral olfactory tract (LOT).
Among white matter tracts, EphA4 expression was detected in the corpus callosum, fornix, and posterior portion of the anterior commissure, but not in the lateral olfactory tract, mammillothalamic tract, or optic chiasm.
GFAP-ir was localized mainly to the subependymal zone and the lateral olfactory tract (LOT) at Day 10, with successive increases in staining in the cellular and plexiform layers at Days 20 and 30.
Intensely stained nonpyramidal neurons resembling those of the ABL were also seen in the cortical nuclei, periamygdaloid cortex, and nucleus of the lateral olfactory tract; these nuclei also contained variable numbers of moderately stained pyramidal cells.
In the forebrain, they were present in the olfactory bulb, nucleus of the lateral olfactory tract, olfactory tubercle, lateral septal nucleus, amygdala, hippocampus, neocortex, caudate-putamen, thalamus and median eminence of the hypothalamus.
Rats were trained on a series of novel 2-odor discrimination problems before and after combined unilateral bulbectomy and posterior transection of the contralateral lateral olfactory tract. The results suggest that lateral olfactory tract afferents to posterior olfactory cortex may play a significant role in short-term memory for odors..
Long-term potentiation was elicited in living slices of rat olfactory cortex by stimulation of the lateral olfactory tract.
A transient expression of atrial natriuretic factor-sensitive guanylyl cyclase activity was observed at postnatal day 8 in the caudate putamen complex, whereas an increase was observed in the lateral olfactory tract from postnatal days 8 to 24. From postnatal day 8 onwards, atrial natriuretic factor-responsive cyclic GMP-immunoreactive cells could be characterized as astrocytes, with the exception of those in the the lateral olfactory tract, where the myelinated fibers became cyclic GMP producing.
The magnocellular and intermediate divisions projected heavily to the homonymous regions on the contralateral side, as well as to the nucleus of the lateral olfactory tract.
Stimulation of the lateral olfactory tract evoked an antidromic pulse followed by a short EPSP, which could also be elicited independently of an antidromic spike in the recorded cell.
Single-pulse stimulation of the lateral olfactory tract (LOT) resulted in a long onset latency (12-20 ms) evoked response in the dentate gyrus of the ipsilateral hippocampal formation.
Two fiber bundles project from the olfactory bulbs into the ventral rostral telencephalon: the medial olfactory tract (tom), embedded in the white matter of the ventral telencephalon (V), which gives rise to a dorsal (tom-d) and a ventral (tom-v) branch, and the lateral olfactory tract (tol). The lateral olfactory tract (tol) runs along the lateral edge of the external sulcus forming a horizontal band.
The PC ("primary olfactory cortex") is the largest area of the mammalian olfactory cortex and receives direct projections from the olfactory bulb via the lateral olfactory tract (LOT).
Levels of biogenic amines were measured in the lateral olfactory tract, prefrontal cortex, striatum, hippocampus and hypothalamus in male and female offspring 21 and 90 days after birth. 5-Hydroxyindole acetic acid (5-HIAA) concentrations and the ratio of 5-HIAA/5-hydroxytryptamine (5-HT, serotonin) were significantly increased in the lateral olfactory tract, prefrontal cortex and hippocampus on postnatal day 90 in male and female offspring following maternal PCB treatment.
The activation of granule cells was achieved by electrical stimulation of the different pathways known to directly activate granule cells [ lateral olfactory tract (LOT), anterior limb of the anterior commissure (AC), and piriform cortex (PC)].
The major alterations of GFAP levels following maternal PCB treatment were significant increases in the lateral olfactory tract (LOT) and the cerebellum (CB) and significant decreases in the brain stem (BS) of the offspring on PND21 and 90.
Two-way ANOVA revealed that estrogen and novelty increased the levels of kOR mRNA in the ventral zone of the medial parvocellular part of the paraventricular nucleus (PVN), but not in the lateral parvocellular part of the PVN, claustrum, nucleus accumbens or the nucleus of the lateral olfactory tract.
Current source density analysis of the field potential profiles evoked by stimulation of the lateral olfactory tract has been utilized to describe the functional circuit activated in rostral and caudal regions of the piriform cortex, before and after the induction of a bicuculline epileptic focus in the anterior piriform cortex. Separate stimulation of the lateral olfactory tract at two sites, caudal and rostral to a tract incision, activates epileptiform potentials that are generated at the site of primary focus in the anterior piriform cortex and travel along associative fibres.
3) On postnatal day 15 and in adult animals, low levels of 5alpha-reductase mRNA were detected in typical white matter structures, such as optical chiasm, lateral olfactory tract, and corpus callosum.
AT1A receptor mRNA was expressed in circumventricular organs, in hypothalamic nuclei like the paraventricular nucleus, in the lateral olfactory tract, in the basolateral amygdaloid and anterior olfactory nuclei, and in the piriform cortex.
Restricted regions of the piriform cortex served by separate contingents of afferent fibres of the lateral olfactory tract were isolated surgically. Current source density (CSD) analysis of field potential laminar profiles evoked by lateral olfactory tract stimulation confirmed that the synaptic sinks induced by distinct associative fibre contingents converge on the apical dendrites of piriform cortex neurons in the superficial lb layer.
Bilateral olfactory bulbectomy (BX) or bilateral transection of the rostral lateral olfactory tract (LOT) at the level of the anterior olfactory nucleus markedly increases gonadotropin secretion and prevents the testicular regression associated with maintenance on short photoperiod in golden hamsters.
FBM (100-500 microM) had little effect on neuronal membrane properties and on postsynaptic potentials evoked by electrical stimulation of lateral olfactory tract terminals, whereas it reduced the duration of presumed Ca++ spikes induced by intracellular Cs+ loading.
The highest densities of the calretinin-immunoreactive neurons were observed in the anterior cortical nucleus, accessory basal nucleus, amygdalohippocampal area, and in the nucleus of the lateral olfactory tract.
All three antagonists significantly reduced mitral/tufted cell excitation of granule cells as measured with extracellular field potentials following antidromic stimulation of the lateral olfactory tract (LOT).
Mitral cells were retrogradely labeled by application of the lipophilic dye 1,1' dihexadecyl-3,3,3'3'-tetramethylin-docarbocyanine perchlorate (DiI) to the lateral olfactory tract.
The most intense hybridization signals were found over neurons in the nucleus of the lateral olfactory tract, in the ventral posterior hippocampus, and in the lateral external subdivision of the parabrachial nucleus.
In layer Ia of the piriform cortex (a target area of projection fibers from the main olfactory bulb), mGluR8-like immunoreactivity (mGluR8-LI) was reduced after transection of the lateral olfactory tract, and mGluR8-LI was observed in axon terminals which were filled with round synaptic vesicles and made asymmetric synapses with dendritic spines..
Field potentials were recorded in the granule cell layer of superfused hemibrain preparations, and the amplitude of the large positive peak was compared following stimulation of the olfactory nerve (ON) and lateral olfactory tract (OT).
In mice, mitral cells are the major efferent neurons of the main olfactory bulb and elongate axons into a very narrow part of the telencephalon to form a fiber bundle referred to as the lateral olfactory tract (LOT).
Animals were trained to discriminate two natural odors while another group was trained to discriminate between a patterned electrical stimulation distributed on the lateral olfactory tract (LOT), labelled olfaco-mimetic stimulation (OMS), used as an olfactory cue versus a natural odor.
At embryonic day 15, a number of labelled fibres form a compact bundle, corresponding to the lateral olfactory tract, that ultimately reaches the prospective primary olfactory cortex.
These areas were not homogeneous in the percentage of each signal type: the percentage of type 3 signals was highest (approximately 30%) in the area near the lateral olfactory tract and < 10% in the most posterodorsal area.
Lower densities of binding were found over the medial preoptic area (MPA), the septohypothalamic nuclei (SHy), the anterior hypothalamic area (AHA), the nuclei of the lateral olfactory tract (LOT), the paraventricular (PV), anteroventral (AV) and intermediodorsal (IMD) nuclei of the thalamus, the medial region of the lateral habenular (Lhb), the nuclei of the stria medullaris (SM), the basolateral (BL) and medial (ME) amygdaloid nuclei, the ventromedial nuclei (VMH), the arcuate nuclei (Arc), the subiculum of the hippocampus (S) and the lateral mammillary nuclei (LM).
They both project to the central medial nucleus, nucleus of the lateral olfactory tract and peri-amygdaloid cortex, but have limited projections to each other.
The main intraamygdaloid targets of the basal nucleus projections are the nucleus of the lateral olfactory tract, the anterior amygdaloid area, the medial and capsular divisions of the central nucleus, the anterior cortical nucleus, and the amygdalohippocampal area.
Large concavities on the ventral side of the brain were interposed between the lateral olfactory tract and the optic tract.
On P14, NMDAR-L mRNA was expressed in layers II-VI of the neocortex, in the entorhinal and piriform cortex, in the subiculum and CA1 field, and in the nucleus of the lateral olfactory tract. In the adult brain, NMDAR-L mRNA was detected predominately in the nucleus of the lateral olfactory tract.
Two fractions of the perfusate collected during tetanic stimulation of the rat lateral olfactory tract, were studied.
A group of interrelated parameters of the membrane metabolism was studied during stimulation of the lateral olfactory tract in the rat brain slices of olfactory cortex.
Staining is apparent in both the lateral olfactory tract and anterior commissure by day 11, and becomes heavy by day 20.
A perfusate collected from donor slices of the olfactory cortex of the brain of rats during tetanization of the lateral olfactory tract (100 imp/sec, 30 sec) induced prolonged changes in the amplitudes of various components of the focal potentials (FP) in recipient slices.
This caused an increased number of oscillations within the network in response to shock stimulation of the lateral olfactory tract, effectively replicating the effect of carbachol on the field potential response in physiological experiments.
In contrast, fibers in the lateral olfactory tract were strongly immunopositive. We noted colocalization of transported BDA and calretinin-immunoreactivity in mitral cells, in fibers in the lateral olfactory tract and in fibers in the piriform cortex. Olfactory bulb lesions produced depletion of calretinin-immunoreactivity in the lateral olfactory tract and the superficial band in the olfactory cortex-related areas.
In this study, we investigated the action of NA on the bulbar neuronal population using evoked field potentials (EFP) elicited antidromically in the olfactory bulb of anesthetized rats, by stimulation of the lateral olfactory tract (LOT).
Recordings were made from SON neurons in large explants and 500 microns thick horizontal slices, containing 2-6 mm of the piriform cortex and lateral olfactory tract (LOT).
Moderate to strong AT1A labeling was found in the anterior olfactory nucleus, the piriform cortex and the nucleus of the lateral olfactory tract.
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