Distribution of dendrites of mitral, displaced mitral, tufted, and granule cells in the rabbit olfactory bulb

Mori, Kensaku; Kawakami, Kiyoshi; Ojima, Hisayuki

doi:10.1002/cne.902190308

Cited by 262 publications

(287 citation statements)

References 32 publications

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“…Mitral-cell dendritic trees are radially symmetric, spanning an area up to 2 mm in diameter, connecting (disynaptically via the granule cells) a single mitral cell with as many as half of all the other mitral cells in the bulb 18,19 . These lateral dendrites release glutamate that depolarizes granule cell dendrites, which in turn release GABA back onto the presynaptic mitral cell (recurrent inhibition), as well as onto other mitral cells (lateral inhibition) 17 .…”

Section: Nih Public Accessmentioning

confidence: 99%

Activity-dependent gating of lateral inhibition in the mouse olfactory bulb

2007

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Lateral inhibition is a circuit motif found throughout the nervous system that often generates contrast enhancement and center-surround receptive fields. We investigated the functional properties of the circuits mediating lateral inhibition between olfactory bulb principal neurons (mitral cells) in vitro. We found that the lateral inhibition received by mitral cells is gated by postsynaptic firing, such that a minimum threshold of postsynaptic activity is required before effective lateral inhibition is recruited. This dynamic regulation allows the strength of lateral inhibition to be enhanced between cells with correlated activity. Simulations show that this regulation of lateral inhibition causes decorrelation of mitral cell activity that is evoked by similar stimuli, even when stimuli have no clear spatial structure. These results show that this previously unknown mechanism for specifying lateral inhibitory connections allows functional inhibitory connectivity to be dynamically remapped to relevant populations of neurons.Lateral inhibitory circuits are known to enhance contrast, facilitate discrimination of similar stimuli and mediate competitive interactions between active neurons 1,2 . These properties are the results of reductions in the degree to which input-driven activity is correlated across neurons responding to stimuli 3 . However, for lateral inhibition to function effectively in this manner, inhibition must be stronger between cells that are activated by similar stimuli (that is, between cells having correlated activity) 4 . When information is represented topographically, similar stimuli activate nearby neurons, so local inhibitory interactions are an effective means for contrast enhancement. This arrangement ensures that cells with correlated activity have strong inhibitory connectivity 5 . However, there are alternative strategies for specifying effective lateral inhibitory connectivity. For example, neurons with similar receptive fields can be connected specifically, independent of their proximity 6 . In this study, we investigate a third possibility, in which the strength of lateral inhibition is dynamically enhanced between neurons with correlated activity.On the basis of the known properties of olfactory bulb circuits, we hypothesized that such a dynamic specification of inhibitory connectivity may be possible and functionally useful in the Correspondence should be addressed to N.N.U. (E-mail: nurban@cmu.edu). Note: Supplementary information is available on the Nature Neuroscience website. 7 . At the level of olfactory receptor-neuron input to the olfactory bulb, stimuli are thought to be represented combinatorially with discontinuous topography [8][9][10][11] . Connectivity between mitral cells (the principal neurons of the olfactory bulb) lacks obvious patterning 12,13 . Single-molecule odorants activate many glomeruli that are distributed widely across the surface of the bulb. Unrelated odors can activate glomeruli in nearby areas and structural similarity of odorant molecules is...

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Section: Nih Public Accessmentioning

confidence: 99%

Activity-dependent gating of lateral inhibition in the mouse olfactory bulb

2007

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“…Granule cells can be classified according to their dendritic branching pattern and synaptic connections with mitral and tufted cells (Mori et al 1983). It remains to be seen whether the sodium spiking patterns may vary depending on the specific dendritic branching pattern of the cell.…”

Section: Dendritic Initiation Of Sodium Spikeletsmentioning

confidence: 99%

Dendritic Sodium Spikelets and Low-Threshold Calcium Spikes in Turtle Olfactory Bulb Granule Cells

Pinato

Midtgaard²

2005

Journal of Neurophysiology

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Active dendritic membrane properties were investigated by whole cell recordings from adult turtle olfactory bulb granule cells. The laminar structure of the olfactory bulb allowed differential polarization of the distal apical dendrites versus the somatic part of the cells by an external electric field. Dendritic depolarization evoked small (∼10 mV) all-or-none depolarizing events of ∼10-ms duration. These spikelets often occurred in bursts at high frequency (≤250 Hz); they were present despite the application of synaptic and gap junction antagonists, but were abolished by TTX and intracellularly applied QX314. The spikelets were interpreted as attenuated sodium spikes initiated in different branches of the granule cells dendrites. They occurred spontaneously, but could also be evoked by excitatory postsynaptic potentials (EPSPs) to the distal dendrites. Spikelets initiated by distal excitation could function as prepotentials for full sodium spikes, in part depending on the level of proximal depolarization. Somatic depolarization by the electric field evoked full sodium spikes as well as low-threshold calcium spikes (LTSs). Calcium imaging revealed that the electrophysiologically identified LTS evoked from the soma was associated with calcium transients in the proximal and the distal dendrites. Our data suggest that the LTS in the soma/proximal dendrites plays a major role in boosting excitability, thus contributing to the initiation of sodium spiking in this compartment. The results furthermore suggest that the LTS and the sodium spikes may act independently or cooperatively to regulate dendritic calcium influx.

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“…Thus, the adult olfactory bulb should comprise neurons with a wide range of maturity levels, given the continual arrival of new cells. Interestingly, granule cells have been reported to be heterogeneous in terms of location and morphology (41)(42)(43) as well as physiological characteristics (A. Carleton, P. E. Castillo, and P.-M.L., unpublished data). A classification of these interneurons can thus be proposed that distinguishes mature from immature granule cells; the latter could be particularly important in olfactory discrimination.…”

Section: Regulation Of Neuron Production and Migration In Adulthoodmentioning

confidence: 99%

Importance of newly generated neurons in the adult olfactory bulb for odor discrimination

Gheusi

Cremer

McLean

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

457

315

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In adult rodents, neurons are continually generated in the subventricular zone of the forebrain, from where they migrate tangentially toward the olfactory bulb, the only known target for these neuronal precursors. Within the main olfactory bulb, they ascend radially into the granule and periglomerular cell layers, where they differentiate mainly into local interneurons. The functional consequences of this permanent generation and integration of new neurons into existing circuits are unknown. To address this question, we used neural cell adhesion molecule-deficient mice that have documented deficits in the migration of olfactory-bulb neuron precursors, leading to about 40% size reduction of this structure. Our anatomical study reveals that this reduction is restricted to the granule cell layer, a structure that contains exclusively ␥-aminobutyric acid (GABA)ergic interneurons. Furthermore, mutant mice were subjected to experiments designed to examine the behavioral consequences of such anatomical alteration. We found that the specific reduction in the newly generated interneuron population resulted in an impairment of discrimination between odors. In contrast, both the detection thresholds for odors and short-term olfactory memory were unaltered, demonstrating that a critical number of bulbar granule cells is crucial only for odor discrimination but not for general olfactory functions.cell adhesion molecules ͉ neurogenesis ͉ interneurons ͉ ␥-aminobutyric acid (GABA)

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Distribution of dendrites of mitral, displaced mitral, tufted, and granule cells in the rabbit olfactory bulb

Cited by 262 publications

References 32 publications

Activity-dependent gating of lateral inhibition in the mouse olfactory bulb

Activity-dependent gating of lateral inhibition in the mouse olfactory bulb

Dendritic Sodium Spikelets and Low-Threshold Calcium Spikes in Turtle Olfactory Bulb Granule Cells

Importance of newly generated neurons in the adult olfactory bulb for odor discrimination

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