Circuit Properties Generating Gamma Oscillations in a Network Model of the Olfactory Bulb

2006 ◽  
Vol 95 (4) ◽  
pp. 2678-2691 ◽  
Author(s):  
Brice Bathellier ◽  
Samuel Lagier ◽  
Philippe Faure ◽  
Pierre-Marie Lledo
Keyword(s):  
Olfactory Bulb ◽  
Firing Rate ◽  
Lateral Inhibition ◽  
Temporal Structure ◽  
Gamma Oscillations ◽  
Synaptic Organization ◽  
Neural Basis ◽  
Sensory Inputs ◽  
Model Based

The study of the neural basis of olfaction is important both for understanding the sense of smell and for understanding the mechanisms of neural computation. In the olfactory bulb (OB), the spatial patterning of both sensory inputs and synaptic interactions is crucial for processing odor information, although this patterning alone is not sufficient. Recent studies have suggested that representations of odor may already be distributed and dynamic in the first olfactory relay. The growing evidence demonstrating a functional role for the temporal structure of bulbar neuronal activity supports this assumption. However, the detailed mechanisms underlying this temporal structure have never been thoroughly studied. Our study focused on gamma (40–100 Hz) network oscillations in the mammalian OB, which is a form of temporal patterning in bulbar activity elicited by olfactory stimuli. We used computational modeling combined with electrophysiological recordings to investigate the basic synaptic organization necessary and sufficient to generate sustained gamma rhythms. We found that features of gamma oscillations obtained in vitro were identical to those of a model based on lateral inhibition as the coupling modality (i.e., low irregular firing rate and high oscillation stability). In contrast, they differed substantially from those of a model based on lateral excitatory coupling (i.e., high regular firing rate and instable oscillations). Therefore we could precisely tune the oscillation frequency by changing the kinetics of inhibitory events supporting the lateral inhibition. Moreover, gradually decreasing GABAergic synaptic transmission decreased the degree of relay neuron synchronization in response to sensory inputs, both theoretically and experimentally. Thus we have shown that lateral inhibition provides a mechanism by which the dynamic processing of odor information might be finely tuned within the OB circuit.

scholarly journals Properties of precise firing synchrony between synaptically coupled cortical interneurons depend on their mode of coupling

2015 ◽  
Vol 114 (1) ◽  
pp. 624-637 ◽  
Author(s):  
Hang Hu ◽  
Ariel Agmon
Keyword(s):  
Firing Rate ◽  
Electrical Coupling ◽  
Gamma Oscillations ◽  
Inhibitory Synapses ◽  
Data Set ◽  
Temporal Precision ◽  
Gamma Frequency ◽  
Rate Dependent ◽  
Cortical Interneurons

Precise spike synchrony has been widely reported in the central nervous system, but its functional role in encoding, processing, and transmitting information is yet unresolved. Of particular interest is firing synchrony between inhibitory cortical interneurons, thought to drive various cortical rhythms such as gamma oscillations, the hallmark of cognitive states. Precise synchrony can arise between two interneurons connected electrically, through gap junctions, chemically, through fast inhibitory synapses, or dually, through both types of connections, but the properties of synchrony generated by these different modes of connectivity have never been compared in the same data set. In the present study we recorded in vitro from 152 homotypic pairs of two major subtypes of mouse neocortical interneurons: parvalbumin-containing, fast-spiking (FS) interneurons and somatostatin-containing (SOM) interneurons. We tested firing synchrony when the two neurons were driven to fire by long, depolarizing current steps and used a novel synchrony index to quantify the strength of synchrony, its temporal precision, and its dependence on firing rate. We found that SOM-SOM synchrony, driven solely by electrical coupling, was less precise than FS-FS synchrony, driven by inhibitory or dual coupling. Unlike SOM-SOM synchrony, FS-FS synchrony was strongly firing rate dependent and was not evident at the prototypical 40-Hz gamma frequency. Computer simulations reproduced these differences in synchrony without assuming any differences in intrinsic properties, suggesting that the mode of coupling is more important than the interneuron subtype. Our results provide novel insights into the mechanisms and properties of interneuron synchrony and point out important caveats in current models of cortical oscillations.

scholarly journals Connectivity and dynamics in the olfactory bulb

2021 ◽  
Author(s):  
David EC Kersen ◽  
Gaia Tavoni ◽  
Vijay Balasubramanian
Keyword(s):  
Olfactory Bulb ◽  
Lateral Inhibition ◽  
Large Scale ◽  
Computational Models ◽  
Granule Cells ◽  
Cell Activity ◽  
Gamma Oscillations ◽  
Scale Model ◽  
Mitral Cells ◽  
Cortical Feedback

Dendrodendritic interactions between excitatory mitral cells and inhibitory granule cells in the olfactory bulb create a dense interaction network, reorganizing sensory representations of odors and, consequently, perception. Large-scale computational models are needed for revealing how the collective behavior of this network emerges from its global architecture. We propose an approach where we summarize anatomical information through dendritic geometry and density distributions which we use to calculate the probability of synapse between mitral and granule cells, while capturing activity patterns of each cell type in the neural dynamical systems theory of Izhikevich. In this way, we generate an efficient, anatomically and physiologically realistic large-scale model of the olfactory bulb network. Our model reproduces known connectivity between sister vs. non-sister mitral cells; measured patterns of lateral inhibition; and theta, beta, and gamma oscillations. It in turn predicts testable relations between network structure, lateral inhibition, and odor pattern decorrelation; between the density of granule cell activity and LFP oscillation frequency; how cortical feedback to granule cells affects mitral cell activity; and how cortical feedback to mitral cells is modulated by the network embedding. Additionally, the methodology we describe here provides a tractable tool for other researchers.

scholarly journals Enhancing GABAergic signaling ameliorates aberrant gamma oscillations of olfactory bulb in AD mouse models

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Ming Chen ◽  
Yunan Chen ◽  
Qingwei Huo ◽  
Lei Wang ◽  
Shuyi Tan ◽  
...  
Keyword(s):  
T Cells ◽  
Olfactory Bulb ◽  
Field Potential ◽  
Gamma Oscillations ◽  
Synaptic Function ◽  
Gaba Uptake ◽  
Olfactory Behavior ◽  
Olfactory Pathway

Abstract Background Before the deposition of amyloid-beta plaques and the onset of learning memory deficits, patients with Alzheimer’s disease (AD) experience olfactory dysfunction, typified by a reduced ability to detect, discriminate, and identify odors. Rodent models of AD, such as the Tg2576 and APP/PS1 mice, also display impaired olfaction, accompanied by aberrant in vivo or in vitro gamma rhythms in the olfactory pathway. However, the mechanistic relationships between the electrophysiological, biochemical and behavioral phenomena remain unclear. Methods To address the above issues in AD models, we conducted in vivo measurement of local field potential (LFP) with a combination of in vitro electro-olfactogram (EOG), whole-cell patch and field recordings to evaluate oscillatory and synaptic function and pharmacological regulation in the olfactory pathway, particularly in the olfactory bulb (OB). Levels of protein involved in excitation and inhibition of the OB were investigated by western blotting and fluorescence staining, while behavioral studies assessed olfaction and memory function. Results LFP measurements demonstrated an increase in gamma oscillations in the OB accompanied by altered olfactory behavior in both APP/PS1 and 3xTg mice at 3–5 months old, i.e. an age before the onset of plaque formation. Fewer olfactory sensory neurons (OSNs) and a reduced EOG contributed to a decrease in the excitatory responses of M/T cells, suggesting a decreased ability of M/T cells to trigger interneuron GABA release indicated by altered paired-pulse ratio (PPR), a presynaptic parameter. Postsynaptically, there was a compensatory increase in levels of GABAAR α1 and β3 subunits and subsequent higher amplitude of inhibitory responses. Strikingly, the GABA uptake inhibitor tiagabine (TGB) ameliorated abnormal gamma oscillations and levels of GABAAR subunits, suggesting a potential therapeutic strategy for early AD symptoms. These findings reveal increased gamma oscillations in the OB as a core indicator prior to onset of AD and uncover mechanisms underlying aberrant gamma activity in the OB. Conclusions This study suggests that the concomitant dysfunction of both olfactory behavior and gamma oscillations have important implications for early AD diagnosis: in particular, awareness of aberrant GABAergic signaling mechanisms might both aid diagnosis and suggest therapeutic strategies for olfactory damage in AD.

scholarly journals Thresholding of sensory inputs by extrasynaptic glutamate receptors in olfactory bulb glomeruli

2018 ◽  
Author(s):  
D.H. Gire ◽  
J.D. Zak ◽  
J.N. Bourne ◽  
N.B. Goodson ◽  
B.E. Lynch ◽  
...  
Keyword(s):  
Information Processing ◽  
Olfactory Bulb ◽  
Lateral Inhibition ◽  
Dynamic Properties ◽  
Odorant Receptor ◽  
Synaptic Inhibition ◽  
Sensory Inputs ◽  
Glutamatergic Signaling ◽  
Triple Cell ◽  
Processing Mechanism

AbstractThe mammalian olfactory bulb has presented a challenging system for understanding information processing, in part because the bulb largely lacks the topographical ordering of neurons that promotes processes such as lateral inhibition. Here we have used dual and triple-cell recordings in rodent bulb slices combined with ultrastructural methods to provide the first experimental evidence for a processing mechanism circumventing this problem that operates at the level of single glomeruli, the bulb’s odorant receptor-specific modules. A key feature is non-traditional, extrasynaptic glutamatergic signaling derived from excitatory interneurons and what it means for the local balance between excitation (E) and inhibition (I). We found that the distinct dynamic properties of extrasynaptic excitation versus synaptic inhibition create a thresholding effect whereby only strong stimuli produce a favorable E/I balance enabling an output. This single-glomerulus threshold could have a number of important functions during natural odor responses, for example enhancing stimulus tuning.

Aluminum Suppresses Effect of Nicotine on Gamma Oscillations (20-40 Hz) in Mouse Hippocampal Slices

2018 ◽  
Vol 17 (6) ◽  
pp. 404-411 ◽  
Author(s):  
Syeda Mehpara Farhat ◽  
Touqeer Ahmed
Keyword(s):  
Nicotinic Acetylcholine Receptors ◽  
Cholinergic System ◽  
Acetylcholine Receptors ◽  
Peak Power ◽  
Hippocampal Slices ◽  
Field Potential ◽  
Gamma Oscillations ◽  
Gamma Oscillation ◽  
Facilitatory Effect

Background: Aluminum (Al) causes neurodegeneration and its toxic effects on cholinergic system in the brain is well documented. However, it is unknown whether and how Al changes oscillation patterns, driven by the cholinergic system, in the hippocampus. Objective: We studied acute effects of Al on nicotinic acetylcholine receptors (nAChRs)-mediated modulation of persistent gamma oscillations in the hippocampus. Method: The field potential recording was done in CA3 area of acute hippocampal slices. Results: Carbachol-induced gamma oscillation peak power increased (1.32±0.09mV2/Hz, P<0.01) in control conditions (without Al) by application of 10µM nicotine as compared to baseline value normalized to 1. This nicotine-induced facilitation of gamma oscillation peak power was found to depend on non-α7 nAChRs. In slices with Al pre-incubation for three to four hours, gamma oscillation peak power was reduced (5.4±1.8mV2/Hz, P<0.05) and facilitatory effect of nicotine on gamma oscillation peak power was blocked as compared to the control (18.06±2.1mV2/Hz) or one hour Al pre-incubated slices (11.3±2.5mV2/Hz). Intriguingly wash-out, after three to four hours of Al incubation, failed to restore baseline oscillation power and its facilitation by nicotine as no difference was observed in gamma oscillation peak power between Al wash-out slices (3.4±1.1mV2/Hz) and slices without washout (3.6±0.9mV2/Hz). Conclusion: This study shows that at cellular level, exposure of hippocampal tissue to Al compromised nAChR-mediated facilitation of cholinergic hippocampal gamma oscillations. Longer in vitro Al exposure caused permanent changes in hippocampal oscillogenic circuitry and changed its sensitivity to nAChR-modulation. This study will help to understand the possible mechanism of cognitive decline induced by Al.

scholarly journals Smells Like Teen Spirit—A Model to Generate Laundry-Associated Malodour In Vitro

2021 ◽  
Vol 9 (5) ◽  
pp. 974
Author(s):  
Marc-Kevin Zinn ◽  
Marco Singer ◽  
Dirk Bockmühl
Keyword(s):  
Volatile Compounds ◽  
Micrococcus Luteus ◽  
Dimethyl Disulfide ◽  
Bacterial Strains ◽  
Dimethyl Trisulfide ◽  
Model Based ◽  
Washing Machines ◽  
Staphylococcus Hominis

Although malodour formation on textiles and in washing machines has been reported to be a very relevant problem in domestic laundry, the processes leading to bad odours have not been studied intensively. In particular, the smell often described as “wet-and-dirty-dustcloth-like malodour” had not been reproduced previously. We developed a lab model based on a bacterial mixture of Micrococcus luteus, Staphylococcus hominis, and Corynebacterium jeikeium, which can produce this odour type and which might allow the detailed investigation of this problem and the development of counteractions. The model uses bacterial strains that have been isolated from malodourous textiles. We could also show that the three volatile compounds dimethyl disulfide, dimethyl trisulfide, and indole contribute considerably to the “wet-fabric-like” malodour. These substances were not only found to be formed in the malodour model but have already been identified in the literature as relevant malodourous substances.

The effects of general anaesthetics on carbachol-evoked gamma oscillations in the rat hippocampus in vitro

2003 ◽  
Vol 44 (7) ◽  
pp. 864-872 ◽  
Author(s):  
R. Dickinson ◽  
S. Awaiz ◽  
M.A. Whittington ◽  
W.R. Lieb ◽  
N.P. Franks
Keyword(s):  
Gamma Oscillations ◽  
Rat Hippocampus

scholarly journals Interglomerular Lateral Inhibition Targeted on External Tufted Cells in the Olfactory Bulb

2013 ◽  
Vol 33 (4) ◽  
pp. 1552-1563 ◽  
Author(s):  
J. D. Whitesell ◽  
K. A. Sorensen ◽  
B. C. Jarvie ◽  
S. T. Hentges ◽  
N. E. Schoppa
Keyword(s):  
Olfactory Bulb ◽  
Lateral Inhibition ◽  
Tufted Cells

Drug-induced liver injury classification model based on in vitro human transcriptomics and in vivo rat clinical chemistry data

2014 ◽  
Vol 2 (4) ◽  
pp. 63-70 ◽  
Author(s):  
Danyel Jennen ◽  
Jan Polman ◽  
Mark Bessem ◽  
Maarten Coonen ◽  
Joost van Delft ◽  
...  
Keyword(s):  
Liver Injury ◽  
Clinical Chemistry ◽  
Classification Model ◽  
Drug Induced ◽  
Drug Induced Liver Injury ◽  
Chemistry Data ◽  
Model Based ◽  
Injury Classification

Inhibition of—But Not between—Orientation Detectors: A Theoretical Note on Illusions of Direction

1980 ◽  
Vol 50 (1) ◽  
pp. 255-262 ◽  
Author(s):  
Willard L. Brigner
Keyword(s):  
Lateral Inhibition ◽  
Single Stimulus ◽  
Single Line ◽  
Collective Effects ◽  
Collective Effect ◽  
Stimulus Line ◽  
Model Based ◽  
Multiple Stimulus

In accounting for illusions of direction, many current models assume lateral inhibition among orientation detectors; however, that assumption is unnecessary. Rather, the illusions can be predicted by a model based on the pattern of inhibition and excitation across orientation detectors as caused by a single stimulus line. From the collective effects of multiple stimulus lines, a pattern of excitation and inhibition results which is perceived as an illusion of direction. This collective effect is predicted by convoluting a function representing physical orientation of stimulus lines with a function representing the pattern of inhibition and excitation elicited by a single line. Both perceived angle-expansion (repulsion) and perceived angle-contraction (attraction) are generated by the model.

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