Nucleus of the lateral olfactory tract

Watanabe K, Kawana E. 1984. Selective retrograde transport of tritiated D-aspartate from the olfactory bulb to the anterior olfactory nucleus, pyriform cortex and nucleus of the lateral olfactory tract in the rat. Brain Res 296 148-151. 

Abbreviations ACo = anterior cortical amygdaloid nucleus AOB = accessory olfactory bulb Me = medial amygdaloid nucleus AON = anterior olfactory nucleus (m = medial division) PCo = posterior cortical amygdaloid nucleus BST = bed nucleus of the stria terminalis DHR = dorsal hippocampal rudiment DPC = dorsal peduncular cortex DR = dorsal raphe nucleus Ent = entorhinal cortex LC = locus coeruleus LPO = lateral preoptic area MOB = main olfactory bulb MnR = median raphe BAOT = nucleus of the accessory olfactory tract NLOT = nucleus of the lateral olfactory tract DB = nucleus of the diagonal band PeCo = periamygdaloid cortex Pir = piriform cortex Tu = olfactory tubercle TT = taenia tecta... 

Commissural projections to the contralateral PC originate nearly exclusively from layer II neurons and travel in the anterior commissure [AC]. These projections innervate more posterior parts of the contralateral PC as well as nearby olfactory cortical sites (periamygdaloid cortex, lateral entorhinal cortex, anterior cortical nucleus, nucleus of the lateral olfactory tract) (Haberly and Price, 1978a,b). The caudally-directed commissural projections arise almost entirely from rostral layer lib neurons. However, there are shorter, less extensive commissural projections from caudal PC that target rostrally adjacent regions. This pathway arises mostly from deep layer III neurons although there is a modest contribution from layer II neurons. 

MeAa medial nucleus of the amygdala, anterior part MeApd medial nucleus of the amygdala, posterodorsal part MeApv medial nucleus of the amygdala, posteroventral part NLOT nucleus of the lateral olfactory tract ONL olfactory nerve layer... 

McDonald, A.J. (1983) Cytoarchitecture of the nucleus of the lateral olfactory tract, a Golgi study in the rat. Brain Res. Bull.. 10, 497-503. 

Fig. 3 Vomeronasal system. Schematic representation of a rodent nasal cavity and brain (lateral view). Accessory olfactory bulb (AOB) mitral cells project to vomeronasal and extended amygdala. Inset The VNO is a bilateral tubular structure located at the base of the nasal septum. VSNs that express the same V1R or V2R converge on a small number of glomeruli in the AOB. Sensory neurons located in the apical layer of the epithelium project to the anterior part of the AOB, whereas those present in the basal layer project to the posterior part. MOE main olfactory epithelium, MOB main olfactory bulb, BSTMPM posteromedial bed nucleus of the stria terminalis, MEA medial amygdaloid nucleus, BACfF bed nucleus of the accessory olfactory tract, PMCO posteromedial cortical amygdaloid area...

Female hamsters with transections of the lateral olfactory tract (LOT efferents and afferents of MOB and AOB) at the level of the anterior olfactory nucleus (AON) are not anosmic, but do show very little interest in male and female odors (Petrulis et al., 1999). This result indicates that chemosensory structures caudal to the cut, such as Pir, MeA and LEnt, are critical for female hamster sex odor preferences and interest in conspecific odors. Removing the VNO has no effect on a female s preferential investigation of male volatile odorants from a male versus a female s odor but did reduce the overall amount of investigation of male flank scent when direct contact was allowed (Petrulis et al., 1999). It appears that, similar to male hamsters, preferential attraction by females toward opposite sex odors at a distance is mediated by the MOS but that the VNS may play a role in chemoinvestigation in circumstances where direct contact with odorants is allowed. 

The output axons of the bulb emerge from its caudolateral aspect to make up the lateral olfactory tract leading to the AOS tertiary structures, most immediately the anterior olfactory nucleus. 

The axons of the mitral cells give off collaterals within the bulb in the internal plexiform and granule cell layers (Mori et al. 1983). The main axons course predominantly in the lateral olfactory tract which forms at the level of the AOB. These caudally directed axons give off collaterals in the anterior olfactory nucleus (AON) and other regions of olfactory cortex (Figs. 13, 18, 19). Tufted cells collateralize to an even greater extent in the bulb than mitral cells. The intrabulbar association pathway formed by CCK-ergic tufted cells was discussed earlier. 

OPC oval paracentral thalamic nucleus 33-35,103-105 OPT olivary pretectal nucleus 38-41, 81-83,110-111 opt optic tract 26-41, 83-89, 91-111 Or oriens layer of the hippocampus 35, 87,106 OT nucleus of the optic tract 39-44, 82-85,109-112 OV olfactory ventricle (olfactory part of lateral ventricle) 1-9, 81-82, 103-104... 

Neuromodulatory transmitter inputs to PC. Darkfield photomicrographs showing the distribution of dopaminergic (a), noradrenergic (b), and serotonergic (c) fibers revealed respectively with immunohistochemistry for tyrosine hydroxylase (TH), dopamine-j8-hydroxylase (DBH), and serotonin (S-HT). Abbreviations Endo, endopiriform nucleus lot, lateral olfactory tract. Reprinted from Handbook of Chem. Neuroanat. Integrated Sys. CNS, Vol. 12, Part III, Chapter III, The Olfactory System, M. Shipley et al., pp. 469-573, 1996, with permission from Elsevier, Ltd... 

---