Topographic organization of tufted cell axonal projections in the hamster main olfactory bulb: An intrabulbar associational system

Schoenfeld, Thomas A.; Marchand, James E.; Macrides, Foteos

doi:10.1002/cne.902350408

Cited by 125 publications

(86 citation statements)

References 66 publications

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“…Previous studies using neural tracers determined that, in adult mice, the intrabulbar map consists of projections that precisely link regions on one side of the bulb to corresponding regions on the opposite side of the same bulb in a spatially conserved manner (Schoenfeld et al, 1985;Belluscio et al, 2002;Lodovichi et al, 2003) (Fig. 1).…”

Section: Resultsmentioning

confidence: 99%

“…tufts (Schoenfeld et al, 1985;Liu and Shipley, 1994;Belluscio et al, 2002;Lodovichi et al, 2003). Within the IPL, external tufted cells make synaptic connections with granule cells, which in turn send dendritic projections toward the apical surface to synapse with the lateral dendrites of mitral and tufted cells (Liu and Shipley, 1994;Shipley and Ennis, 1996).…”

Section: Discussionmentioning

confidence: 99%

“…This organization is less clear in the olfactory system in which olfactory sensory neurons (OSNs) that express a common odorant receptor are broadly scattered throughout the nasal turbinates but coalesce to form glomerular maps as their axons reach the bulb (Ressler et al, 1994;Vassar et al, 1994). Recent studies have shown that a second-order map also exists that precisely links the glomerular maps within each bulb through a reciprocal projection mediated by external tufted cells (ETCs) (Schoenfeld et al, 1985;Belluscio et al, 2002;Lodovichi et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

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Activity-Dependent Plasticity in the Olfactory Intrabulbar Map

Marks¹,

Cheng²,

Cummings³

et al. 2006

J. Neurosci.

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In mammals, each olfactory bulb contains two mirror-symmetric glomerular maps. Isofunctional glomeruli within each bulb are specifically linked through a set of reciprocal intrabulbar projections (IBPs) to form an intrabulbar map. We injected neural tracers into the glomerular layer on one side of the bulb and examined the resulting projection on the opposite side. In adult mice, the size of the projection tuft is directly proportional to the size of the injected region. Using this ratio as a measure of IBP maturity, we find an immature 5:1 projection to injection ratio at 1 week of age that gradually refines to a mature 1:1 by 7 weeks. Moreover, whereas the glomerular map is able to form despite the elimination of odorant-induced activity, the intrabulbar map shows clear activity dependence for its precise formation. Here we show through experiments with both naris-occluded and anosmic mice that odorant-induced activity is not required to establish IBPs but is crucial for projection refinement. In contrast, increased glomerular activation through exposure to distinct odorants during map development can accelerate the refinement of projections associated with the activated glomeruli. These findings illustrate a clear role for odorant-induced activity in shaping the internal circuitry of the bulb. Interestingly, activity deprivation can alter the organization of both the developing and the mature map to the same degree, demonstrating that intrabulbar map plasticity is maintained into adulthood with no discernible critical period.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Activity-Dependent Plasticity in the Olfactory Intrabulbar Map

Marks¹,

Cheng²,

Cummings³

et al. 2006

J. Neurosci.

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“…In addition, the two types of neurons differ in the size of terminal tuft of primary dendrite within the glomeruli, projection pattern of their secondary dendrites, laminar distribution of axon-collaterals within the OB, and the pattern of axonal projection to the olfactory cortex ( Fig. 1) (Haberly and Price 1977;Mori et al 1983;Orona et al 1984;Pinching and Powell 1971;Schoenfeld and Macrides 1984;Schoenfeld et al 1985;Scott et al 1980;Skeen and Hall 1977).…”

Section: Introductionmentioning

confidence: 99%

Mitral and Tufted Cells Differ in the Decoding Manner of Odor Maps in the Rat Olfactory Bulb

Nagayama

Takahashi

Yoshihara

et al. 2004

Journal of Neurophysiology

188

179

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. Mitral and tufted cells differ in the decoding manner of odor maps in the rat olfactory bulb. J Neurophysiol 91: 2532-2540, 2004. First published February 11, 2004 10.1152/jn.01266.2003. Mitral and tufted cells in the mammalian olfactory bulb are principal neurons, each type having distinct projection pattern of their dendrites and axons. The morphological difference suggests that mitral and tufted cells are functionally distinct and may process different aspects of olfactory information. To examine this possibility, we recorded odorant-evoked spike responses from mitral and middle tufted cells in the aliphatic acid-and aldehyde-responsive cluster at the dorsomedial part of the rat olfactory bulb. Homologous series of aliphatic acids and aldehydes were used for odorant stimulation. In response to adequate odorants, mitral cells showed spike responses with relatively low firing rates, whereas middle tufted cells responded with higher firing rates. Examination of the molecular receptive range (MRR) indicated that most mitral cells exhibited a robust inhibitory MRR, whereas a majority of middle tufted cells showed no or only a weak inhibitory MRR. In addition, structurally different odorants that activated neighboring clusters inhibited the spike activity of mitral cells, whereas they caused no or only a weak inhibition in the middle tufted cells. Furthermore, responses of mitral cells to an adequate excitatory odorant were greatly inhibited by mixing the odorant with other odorants that activated neighboring glomeruli. In contrast, odorants that activated neighboring glomeruli did not significantly inhibit the responses of middle tufted cells to the adequate excitatory odorant. These results indicate a clear difference between mitral and middle tufted cells in the manner of decoding the glomerular odor maps.

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“…After tracer injections into the tenrec' s OfB, distinct anterograde and retrograde labeling was seen in the medial wall of the same bulb. This projection system corresponds to the intrabulbar association system described in hamster and rat Schoenfeld et al, 1985;Liu and Shipley, 1994). Characteristically, this projection system is comprised of fibers located in the PxI, and the perikarya are distributed in the PxE and the glomerular layer.…”

Section: Intrabulbar and Interbulbar Connectionsmentioning

confidence: 97%

Olfactory bulb and retrobulbar regions in the hedgehog tenrec: Organization and interconnections

Radtke‐Schuller

Künzle

2000

J. Comp. Neurol.

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The Madagascan lesser hedgehog tenrec (Echinops telfairi) is a terrestrial, nocturnal insectivore with a low encephalization index and a huge olfactory bulb. To gain insight into the organization and evolution of olfactory regions in placental mammals, the cytoarchitecture (Nissl), neurochemical attributes [zinc and acetylcholinesterase stain, nicotinamide adenine dinucleotide phosphate (NADPh)-diaphorase, and calcium-binding proteins], and interconnections (injections of wheat germ agglutinin-horseradish peroxidase and biotinylated dextran amine) of tenrec bulbar and retrobulbar regions were examined. The tenrec has a well-laminated main olfactory bulb, and modified (atypical) glomeruli are found that, to date, have been demonstrated only in murine rodents. Compared with the main olfactory bulb, the accessory bulb is relatively small, with clearly different staining characteristics, particularly with respect to NADPh-diaphorase, anticalbindin, and anticalretinin. External and central anterior olfactory nuclei also show characteristic cytoarchitectural and chemoarchitectural features. The medial olfactory peduncle seems to differ considerably from that in rodents. A small taenial structure can be separated from the hippocampal continuation. This taenia tecti presumably corresponds to the superior part of the tenia tecti in rodents, but no homologue of the rodent's prominent inferior taenia tecti could be found. The connections of bulbar and retrobulbar regions are similar to those seen in other mammals. Interbulbar projection systems connect the two olfactory bulbs through an external (topographic) and central (nontopographic) anterior nucleus; however, the topographic arrangement of the intrabulbar association system seems to differ from that seen in rodents. A reciprocity of direct olfactory bulb connections with the frontal (sulcal/orbital) cortex was found in the tenrec that has not been reported so far in other species.

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Topographic organization of tufted cell axonal projections in the hamster main olfactory bulb: An intrabulbar associational system

Cited by 125 publications

References 66 publications

Activity-Dependent Plasticity in the Olfactory Intrabulbar Map

Activity-Dependent Plasticity in the Olfactory Intrabulbar Map

Mitral and Tufted Cells Differ in the Decoding Manner of Odor Maps in the Rat Olfactory Bulb

Olfactory bulb and retrobulbar regions in the hedgehog tenrec: Organization and interconnections

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