Intracellular responses of identified rat olfactory bulb interneurons to electrical and odor stimulation

1990 ◽  
Vol 64 (3) ◽  
pp. 932-947 ◽  
Author(s):  
D. P. Wellis ◽  
J. W. Scott
Keyword(s):  
Electrical Stimulation ◽  
Olfactory Bulb ◽  
Granule Cell ◽  
Action Potentials ◽  
Granule Cells ◽  
Olfactory Nerve ◽  
Mitral Cell ◽  
Intracellular Recordings ◽  
Postsynaptic Potential ◽  
Stimulation Of

1. Intracellular recordings were made from 28 granule cells and 6 periglomerular cells of the rat olfactory bulb during odor stimulation and electrical stimulation of the olfactory nerve layer (ONL) and lateral olfactory tract (LOT). Neurons were identified by injection of horseradish peroxidase (HRP) or biocytin and/or intracellular response characteristics. Odorants were presented in a cyclic sniff paradigm, as reported previously. 2. All interneurons could be activated from a wide number of stimulation sites on the ONL, with distances exceeding their known dendritic spreads and the dispersion of nerve fibers within the ONL, indicating that multisynaptic pathways must also exist at the glomerular region. All types of interneurons also responded to odorant stimulation, showing a variety of responses. 3. Granule cells responded to electrical stimulation of the LOT and ONL as reported previously. However, intracellular potential, excitability, and conductance analysis suggested that the mitral cell-mediated excitatory postsynaptic potential (EPSP) is followed by a long inhibitory postsynaptic potential (IPSP). An early negative potential, before the EPSP, was also observed in every granule cell and correlated with component I of the extracellular LOT-induced field potential. We have interpreted this negativity as a "field effect," that may be diagnostic of granule cells. 4. Most granule cells exhibited excitatory responses to odorant stimulation. Odors could produce spiking responses that were either nonhabituating (response to every sniff) or rapidly habituating (response to first sniff only). Other granule cells, while spiking to electrical stimulation, showed depolarizations that did not evoke spikes to odor stimulation. These depolarizations were transient with each sniff or sustained across a series of sniffs. These physiological differences to odor stimulation correlated with granule cell position beneath the mitral cell layer for 12 cells, suggesting that morphological subtypes of granule cells may show physiological differences. Some features of the granule cell odor responses seem to correlate with some of the features we have observed in mitral/tufted cell intracellular recordings. Only one cell showed inhibition to odors. 5. Periglomerular (PG) cells showed a response to ONL stimulation that was unlike that found in other olfactory bulb neurons. There was a long-duration hyperpolarization after a spike and large depolarization or burst of spikes (20-30 ms in duration). Odor stimulation produced simple bursts of action potentials, Odor stimulation produced simple bursts of action potentials, suggesting that PG cells may simply follow input from the olfactory nerve.(ABSTRACT TRUNCATED AT 400 WORDS)

Olfactory bulb potentials evoked by electrical stimulation of the contralateral bulb

1959 ◽  
Vol 196 (2) ◽  
pp. 327-329 ◽  
Author(s):  
Raymond R. Walsh
Keyword(s):  
Electrical Stimulation ◽  
Olfactory Bulb ◽  
Short Duration ◽  
Evoked Potential ◽  
Plexiform Layer ◽  
Electrical Stimulus ◽  
Tetanic Stimulation ◽  
Granular Cells ◽  
Postsynaptic Potential ◽  
Stimulation Of

A single, short-duration electrical stimulus delivered to one olfactory bulb evokes a potential in the contralateral bulb. As recorded with a unipolar electrode, the potential is negative central to, and positive peripheral to the external plexiform layer. Bipolar recordings from multiple sites show that the potential is not actively propagated. The potential summates in response to tetanic stimulation and is blocked by anoxia and dimethyl ether d-tubocurarine. In addition to confirming the existence of an interolfactory bulb system, the electrophysiological evidence in conjunction with known anatomical relationships strongly suggests that the evoked potential is a postsynaptic potential of the internal granular cells.

Inhibition of Backpropagating Action Potentials in Mitral Cell Secondary Dendrites

2002 ◽  
Vol 88 (1) ◽  
pp. 64-85 ◽  
Author(s):  
Graeme Lowe
Keyword(s):  
Olfactory Bulb ◽  
Granule Cell ◽  
Action Potentials ◽  
Flash Photolysis ◽  
Glutamate Release ◽  
Mitral Cell ◽  
Repetitive Firing ◽  
Inhibitory Input ◽  
Mitral Cells ◽  
Distal Dendrite

The mammalian olfactory bulb is a geometrically organized signal-processing array that utilizes lateral inhibitory circuits to transform spatially patterned inputs. A major part of the lateral circuitry consists of extensively radiating secondary dendrites of mitral cells. These dendrites are bidirectional cables: they convey granule cell inhibitory input to the mitral soma, and they conduct backpropagating action potentials that trigger glutamate release at dendrodendritic synapses. This study examined how mitral cell firing is affected by inhibitory inputs at different distances along the secondary dendrite and what happens to backpropagating action potentials when they encounter inhibition. These are key questions for understanding the range and spatial dependence of lateral signaling between mitral cells. Backpropagating action potentials were monitored in vitro by simultaneous somatic and dendritic whole cell recording from individual mitral cells in rat olfactory bulb slices, and inhibition was applied focally to dendrites by laser flash photolysis of caged GABA (2.5-μm spot). Photolysis was calibrated to activate conductances similar in magnitude to GABAA-mediated inhibition from granule cell spines. Under somatic voltage-clamp with CsCl dialysis, uncaging GABA onto the soma, axon initial segment, primary and secondary dendrites evoked bicuculline-sensitive currents (up to −1.4 nA at −60 mV; reversal at ∼0 mV). The currents exhibited a patchy distribution along the axon and dendrites. In current-clamp recordings, repetitive firing driven by somatic current injection was blocked by uncaging GABA on the secondary dendrite ∼140 μm from the soma, and the blocking distance decreased with increasing current. In the secondary dendrites, backpropagated action potentials were measured 93–152 μm from the soma, where they were attenuated by a factor of 0.75 ± 0.07 (mean ± SD) and slightly broadened (1.19 ± 0.10), independent of activity (35–107 Hz). Uncaging GABA on the distal dendrite had little effect on somatic spikes but attenuated backpropagating action potentials by a factor of 0.68 ± 0.15 (0.45–0.60 μJ flash with 1-mM caged GABA); attenuation was localized to a zone of width 16.3 ± 4.2 μm around the point of GABA release. These results reveal the contrasting actions of inhibition at different locations along the dendrite: proximal inhibition blocks firing by shunting somatic current, whereas distal inhibition can impose spatial patterns of dendrodendritic transmission by locally attenuating backpropagating action potentials. The secondary dendrites are designed with a high safety factor for backpropagation, to facilitate reliable transmission of the outgoing spike-coded data stream, in parallel with the integration of inhibitory inputs.

scholarly journals Zinc released from olfactory bulb glomeruli by patterned electrical stimulation of the olfactory nerve

Metallomics ◽  
2013 ◽  
Vol 5 (3) ◽  
pp. 208 ◽  
Author(s):  
Laura J. Blakemore ◽  
Elisa Tomat ◽  
Stephen J. Lippard ◽  
Paul Q. Trombley
Keyword(s):  
Electrical Stimulation ◽  
Olfactory Bulb ◽  
Olfactory Nerve ◽  
Stimulation Of

Synaptic Organization and Neurotransmitters in the Rat Accessory Olfactory Bulb

1999 ◽  
Vol 81 (1) ◽  
pp. 345-355 ◽  
Author(s):  
Changping Jia ◽  
Wei R. Chen ◽  
Gordon M. Shepherd
Keyword(s):  
Olfactory Bulb ◽  
Granule Cells ◽  
Mitral Cell ◽  
Activity Period ◽  
Mitral Cells ◽  
Accessory Olfactory Bulb ◽  
Field Potentials ◽  
Synaptic Organization ◽  
Evoked Field Potentials ◽  
Stimulation Of

Jia, Changping, Wei R. Chen, and Gordon M. Shepherd. Synaptic organization and neurotransmitters in the rat accessory olfactory bulb. J. Neurophysiol. 81: 345–355, 1999. The accessory olfactory bulb (AOB) is the first relay station in the vomeronasal system and may play a critical role in processing pheromone signals. The AOB shows similar but less distinct lamination compared with the main olfactory bulb (MOB). In this study, synaptic organization of the AOB was analyzed in slice preparations from adult rats by using both field potential and patch-clamp recordings. Stimulation of the vomeronasal nerve (VN) evoked field potentials that showed characteristic patterns in different layers of the AOB. Current source density (CSD) analysis of the field potentials revealed spatiotemporally separated loci of inward current (sinks) that represented sequential activation of different neuronal components: VN activity (period I), synaptic excitation of mitral cell apical dendrites (period II), and activation of granule cells by mitral cell basal dendrites (period III). 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). Whole cell patch recordings from mitral and granule cells of the AOB supported that mitral cells are excited by VN terminals and subsequently activate granule cells through dendrodendritic synapses. Both CSD analysis and patch recordings provided evidence that glutamate is the neurotransmitter at the vomeronasal receptor neuron; mitral cell synapses and both NMDA and non-NMDA receptors are involved. We also demonstrated electrophysiologically that reciprocal interaction between mitral and granule cells in the AOB is through the dendrodendritic reciprocal synapses. The neurotransmitter at the mitral-to-granule synapses is glutamate and at the granule-to-mitral synapse is γ-aminobutyric acid. The synaptic interactions among receptor cell terminals, mitral cells, and granule cells in the AOB are therefore similar to those in the MOB, suggesting that processing of chemosensory information in the AOB shares similarities with that in the MOB.

Presynaptic inhibition of transmission from identified interneurons in locust central nervous system

1981 ◽  
Vol 45 (3) ◽  
pp. 501-515 ◽  
Author(s):  
K. G. Pearson ◽  
C. S. Goodman
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Electrical Stimulation ◽  
Action Potentials ◽  
Presynaptic Inhibition ◽  
Auditory Stimuli ◽  
Movement Detector ◽  
Intracellular Recordings ◽  
Contralateral Movement ◽  
Stimulation Of

1. Intracellular recordings near the output terminals of an identified interneuron (the descending contralateral movement detector, DCMD) in the locust revealed the occurrence of depolarizing synaptic potentials. These presynaptic depolarizing potentials were evoked by spikes in both DCMDs, by auditory stimuli, and by electrical stimulation of the pro- to mesothoracic connectives. The occurrence of the depolarizing potentials decreased the amplitude of the action potentials close to the output terminals. 2. The stimuli that produced depolarizing potentials in the presynaptic terminals reduced the amplitude of the monosynaptic excitatory postsynaptic potentials evoked by the DCMDs in identified follower interneurons. We conclude that at least part of this reduction in transmission from the DCMDs results from presynaptic inhibition and that the presynaptic inhibition is related to a reduction in the amplitude of the presynaptic action potentials. 3. We propose that the function of the presynaptic inhibition of the DCMDs is to ensure that the interneurons triggering a jump are never activated by the DCMDs in the absence of proprioceptive signals from the legs indicating the animal's readiness to jump.

scholarly journals Complementary Postsynaptic Activity Patterns Elicited in Olfactory Bulb by Stimulation of Mitral/Tufted and Centrifugal Fiber Inputs to Granule Cells

2007 ◽  
Vol 97 (1) ◽  
pp. 296-306 ◽  
Author(s):  
Nora Laaris ◽  
Adam Puche ◽  
Matthew Ennis
Keyword(s):  
Olfactory Bulb ◽  
Ampa Receptor ◽  
Granule Cell ◽  
Granule Cells ◽  
Activity Patterns ◽  
Evoked Responses ◽  
Field Potentials ◽  
Optical Signals ◽  
Postsynaptic Activity ◽  
Stimulation Of

Main olfactory bulb (MOB) granule cells receive spatially segregated glutamatergic synaptic inputs from the dendrites of mitral/tufted cells as well as from the axons of centrifugal fibers (CFFs) originating in olfactory cortical areas. Dendrodendritic synapses from mitral/tufted cells occur on granule cell distal dendrites in the external plexiform layer (EPL), whereas CFFs preferentially target the somata/proximal dendrites of granule cells in the granule cell layer (GCL). In the present study, tract tracing, and recordings of field potentials and voltage-sensitive dye optical signals were used to map activity patterns elicited by activation of these two inputs to granule cells in mouse olfactory bulb slices. Stimulation of the lateral olfactory tract (LOT) produced a negative field potential in the EPL and a positivity in the GCL. CFF stimulation produced field potentials of opposite polarity in the EPL and GCL to those elicited by LOT. LOT-evoked optical signals appeared in the EPL and spread subsequently to deeper layers, whereas CFF-evoked responses appeared in the GCL and then spread superficially. Evoked responses were reduced by N-methyl-d-aspartate (NMDA) receptor antagonists and completely suppressed by AMPA receptor antagonists. Reduction of extracellular Mg2+ enhanced the strength and spatiotemporal extent of the evoked responses. These and additional findings indicate that LOT- and CFF-evoked field potentials and optical signals reflect postsynaptic activity in granule cells, with moderate NMDA and dominant AMPA receptor components. Taken together, these results demonstrate that LOT and CFF stimulation in MOB slices selectively activate glutamatergic inputs to the distal dendrites versus somata/proximal dendrites of granule cells.

Group I Metabotropic Glutamate Receptors Are Differentially Expressed by Two Populations of Olfactory Bulb Granule Cells

2007 ◽  
Vol 97 (4) ◽  
pp. 3136-3141 ◽  
Author(s):  
Thomas Heinbockel ◽  
Kathryn A. Hamilton ◽  
Matthew Ennis
Keyword(s):  
Olfactory Bulb ◽  
Glutamate Receptors ◽  
Metabotropic Glutamate Receptors ◽  
Granule Cells ◽  
Mitral Cell ◽  
Mitral Cells ◽  
Patch Clamp Recording ◽  
Metabotropic Glutamate ◽  
Group I ◽  
Bath Application

In the main olfactory bulb, several populations of granule cells (GCs) can be distinguished based on the soma location either superficially, interspersed with mitral cells within the mitral cell layer (MCL), or deeper, within the GC layer (GCL). Little is known about the physiological properties of superficial GCs (sGCs) versus deep GCs (dGCs). Here, we used patch-clamp recording methods to explore the role of Group I metabotropic glutamate receptors (mGluRs) in regulating the activity of GCs in slices from wildtype and mGluR−/− mutant mice. In wildtype mice, bath application of the selective Group I mGluR agonist DHPG depolarized and increased the firing rate of both GC subtypes. In the presence of blockers of fast synaptic transmission (APV, CNQX, gabazine), DHPG directly depolarized both GC subtypes, although the two GC subtypes responded differentially to DHPG in mGluR1−/− and mGluR5−/− mice. DHPG depolarized sGCs in slices from mGluR5−/− mice, although it had no effect on sGCs in slices from mGluR1−/− mice. By contrast, DHPG depolarized dGCs in slices from mGluR1−/− mice but had no effect on dGCs in slices from mGluR5−/− mice. Previous studies showed that mitral cells express mGluR1 but not mGluR5. The present results therefore suggest that sGCs are more similar to mitral cells than dGCs in terms of mGluR expression.

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