scholarly journals Changes in weak pair-wise correlations during running reshapes network state in the main olfactory bulb

2020 ◽  
Author(s):  
Udaysankar Chockanathan ◽  
Emily J. W. Crosier ◽  
Spencer Waddle ◽  
Edward Lyman ◽  
Richard C. Gerkin ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Spontaneous Activity ◽  
Olfactory System ◽  
Activity Patterns ◽  
Higher Order ◽  
High Density ◽  
Main Olfactory Bulb ◽  
Population Activity ◽  
Maximum Entropy Models ◽  
Electrophysiological Recordings

AbstractNeural codes for sensory representations are thought to reside in a broader space defined by the patterns of spontaneous activity that occur when stimuli are not being presented. To understand the structure of this spontaneous activity in the olfactory system, we performed high-density recordings of population activity in the main olfactory bulb of awake mice. We found that spontaneous activity patterns of ensembles of mitral and tufted (M/T) cells in the main olfactory bulb changed dramatically during locomotion, including decreases in pairwise correlations between neurons and increases in the entropy of the population. Maximum entropy models of the ensemble activity revealed that pair-wise interactions were better at predicting patterns of activity when the animal was stationary than while running, suggesting that higher order (3rd, 4th order) interactions between neurons shape activity during locomotion. Taken together, we found that locomotion influenced the structure of spontaneous population activity at the earliest stages of olfactory processing, 1 synapse away from the sensory receptors in the nasal epithelium.New and NoteworthyThe organization and structure of spontaneous population activity in the olfactory system places constraints of how odor information is represented. Using high-density electrophysiological recordings of mitral and tufted cells, we found that running increases the dimensionality of spontaneous activity, implicating higher-order interactions among neurons during locomotion. Behavior thus flexibly alters neuronal activity at the earliest stages of sensory processing.

scholarly journals Changes in pairwise correlations during running reshape global network state in the main olfactory bulb

2021 ◽  
Vol 125 (5) ◽  
pp. 1612-1623
Author(s):  
Udaysankar Chockanathan ◽  
Emily J. W. Crosier ◽  
Spencer Waddle ◽  
Edward Lyman ◽  
Richard C. Gerkin ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Sensory Processing ◽  
Olfactory System ◽  
Global Network ◽  
Main Olfactory Bulb ◽  
Population Activity ◽  
Network State ◽  
Electrophysiological Recordings ◽  
Pairwise Correlations ◽  
Locomotion Behavior

The organization and structure of spontaneous population activity in the olfactory system places constraints of how odor information is represented. Using high-density electrophysiological recordings of mitral and tufted cells, we found that running increases the dimensionality of spontaneous activity, implicating higher order interactions among neurons during locomotion. Behavior, thus, flexibly alters neuronal activity at the earliest stages of sensory processing.

scholarly journals Representational drift in the mouse visual cortex

2020 ◽  
Author(s):  
Daniel Deitch ◽  
Alon Rubin ◽  
Yaniv Ziv
Keyword(s):  
Large Scale ◽  
Activity Patterns ◽  
Population Level ◽  
Population Activity ◽  
Cortical Areas ◽  
Electrophysiological Recordings ◽  
The Face ◽  
Visual Cortical ◽  
Mouse Visual Cortex ◽  
Over Time

AbstractNeuronal representations in the hippocampus and related structures gradually change over time despite no changes in the environment or behavior. The extent to which such ‘representational drift’ occurs in sensory cortical areas and whether the hierarchy of information flow across areas affects neural-code stability have remained elusive. Here, we address these questions by analyzing large-scale optical and electrophysiological recordings from six visual cortical areas in behaving mice that were repeatedly presented with the same natural movies. We found representational drift over timescales spanning minutes to days across multiple visual areas. The drift was driven mostly by changes in individual cells’ activity rates, while their tuning changed to a lesser extent. Despite these changes, the structure of relationships between the population activity patterns remained stable and stereotypic, allowing robust maintenance of information over time. Such population-level organization may underlie stable visual perception in the face of continuous changes in neuronal responses.

scholarly journals The Source of Spontaneous Activity in the Main Olfactory Bulb of the Rat

PLoS ONE ◽  
2011 ◽  
Vol 6 (8) ◽  
pp. e23990 ◽  
Author(s):  
Josif Stakic ◽  
Jessica M. Suchanek ◽  
Geoffrey P. Ziegler ◽  
Edwin R. Griff
Keyword(s):  
Olfactory Bulb ◽  
Spontaneous Activity ◽  
Main Olfactory Bulb

scholarly journals Paradoxically sparse chemosensory tuning in broadly-integrating external granule cells in the mouse accessory olfactory bulb

2019 ◽  
Author(s):  
Xingjian Zhang ◽  
Julian P. Meeks
Keyword(s):  
Patch Clamp ◽  
Olfactory Bulb ◽  
Olfactory System ◽  
Granule Cells ◽  
Ex Vivo ◽  
Accessory Olfactory Bulb ◽  
Main Olfactory Bulb ◽  
Patch Clamp Electrophysiology ◽  
Accessory Olfactory System ◽  
Critical Circuit

AbstractThe accessory olfactory bulb (AOB) is a critical circuit in the mouse accessory olfactory system (AOS), but AOB processing is poorly understood compared to the main olfactory bulb (MOB). We used 2-photon GCaMP6f Ca2+ imaging in an ex vivo preparation to study the chemosensory tuning of AOB external granule cells (EGCs), an interneuron population hypothesized to broadly integrate from mitral cells (MCs). We measured MC and EGC tuning to natural chemosignal blends and monomolecular ligands, finding that EGC tuning was far sparser than MC tuning. Simultaneous patch-clamp electrophysiology and Ca2+ imaging indicated that this was only partially explained by lower GCaMP6f-to-spiking ratios in EGCs compared to MCs. Ex vivo patch-clamp recordings revealed that EGC subthreshold responsivity was broad, but monomolecular ligand responses were insufficient to elicit spiking. These results indicate that EGC spiking is selectively engaged by chemosensory blends, suggesting different roles for EGCs than analogous interneurons in the MOB.

scholarly journals Plume Dynamics Structure the Spatiotemporal Activity of Mitral/Tufted Cell Networks in the Mouse Olfactory Bulb

2021 ◽  
Vol 15 ◽  
Author(s):  
Suzanne M. Lewis ◽  
Lai Xu ◽  
Nicola Rigolli ◽  
Mohammad F. Tariq ◽  
Lucas M. Suarez ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Olfactory System ◽  
Large Scale ◽  
Early Stage ◽  
Wide Field ◽  
Flow Conditions ◽  
Population Activity ◽  
Plume Dynamics ◽  
Olfactory Glomeruli ◽  
Odor Plumes

Although mice locate resources using turbulent airborne odor plumes, the stochasticity and intermittency of fluctuating plumes create challenges for interpreting odor cues in natural environments. Population activity within the olfactory bulb (OB) is thought to process this complex spatial and temporal information, but how plume dynamics impact odor representation in this early stage of the mouse olfactory system is unknown. Limitations in odor detection technology have made it difficult to measure plume fluctuations while simultaneously recording from the mouse's brain. Thus, previous studies have measured OB activity following controlled odor pulses of varying profiles or frequencies, but this approach only captures a subset of features found within olfactory plumes. Adequately sampling this feature space is difficult given a lack of knowledge regarding which features the brain extracts during exposure to natural olfactory scenes. Here we measured OB responses to naturally fluctuating odor plumes using a miniature, adapted odor sensor combined with wide-field GCaMP6f signaling from the dendrites of mitral and tufted (MT) cells imaged in olfactory glomeruli of head-fixed mice. We precisely tracked plume dynamics and imaged glomerular responses to this fluctuating input, while varying flow conditions across a range of ethologically-relevant values. We found that a consistent portion of MT activity in glomeruli follows odor concentration dynamics, and the strongest responding glomeruli are the best at following fluctuations within odor plumes. Further, the reliability and average response magnitude of glomerular populations of MT cells are affected by the flow condition in which the animal samples the plume, with the fidelity of plume following by MT cells increasing in conditions of higher flow velocity where odor dynamics result in intermittent whiffs of stronger concentration. Thus, the flow environment in which an animal encounters an odor has a large-scale impact on the temporal representation of an odor plume in the OB. Additionally, across flow conditions odor dynamics are a major driver of activity in many glomerular networks. Taken together, these data demonstrate that plume dynamics structure olfactory representations in the first stage of odor processing in the mouse olfactory system.

scholarly journals Conserved structures of neural activity in sensorimotor cortex of freely moving rats allow cross-subject decoding

2021 ◽  
Author(s):  
Svenja Melbaum ◽  
David Eriksson ◽  
Thomas Brox ◽  
Ilka Diester
Keyword(s):  
Sensorimotor Cortex ◽  
Activity Patterns ◽  
Population Activity ◽  
Electrophysiological Recordings ◽  
Primary Sensory Cortex ◽  
Behavioral Paradigm ◽  
Structure Of Population ◽  
Freely Moving ◽  
Low Dimensional ◽  
Neuronal Code

Our knowledge about neuronal activity in the sensorimotor cortex relies primarily on stereotyped movements which are strictly controlled via the experimental settings. It remains unclear how results can be carried over to less constrained behavior, i.e. freely moving subjects. Towards this goal, we developed a self-paced behavioral paradigm which encouraged rats to conduct different types of movements. Via bilateral electrophysiological recordings across the entire sensorimotor cortex and simultaneous paw tracking, we identified behavioral coupling of neurons with lateralization and an anterior-posterior gradient from premotor to primary sensory cortex. The structure of population activity patterns was conserved across animals, in spite of severe undersampling of the total number of neurons and variations of electrode positions across individuals. Via alignments of low-dimensional neural manifolds, we demonstrate cross-subject and cross-session generalization in a decoding task arguing for a conserved neuronal code.

Localization of α1-2 Fucose Glycan in the Mouse Olfactory Pathway

2016 ◽  
Vol 203 (1) ◽  
pp. 20-28 ◽  
Author(s):  
Daisuke Kondoh ◽  
Akihiro Kamikawa ◽  
Motoki Sasaki ◽  
Nobuo Kitamura
Keyword(s):  
Olfactory Bulb ◽  
Olfactory System ◽  
Plexiform Layer ◽  
Basal Region ◽  
Main Olfactory Bulb ◽  
Olfactory Pathway ◽  
Ulex Europaeus ◽  
Receptor Cells ◽  
Ulex Europaeus Agglutinin I ◽  
Local Circuits

Glycoconjugates in the olfactory system play critical roles in neuronal formation, and α1-2 fucose (α1-2Fuc) glycan mediates neurite outgrowth and synaptic plasticity. Histochemical findings of α1-2Fuc glycan in the mouse olfactory system detected using Ulex europaeus agglutinin-I (UEA-I) vary. This study histochemically assessed the main olfactory and vomeronasal pathways in male and female ICR and C57BL/6J mice aged 3-4 months using UEA-I. Ulex europaeus agglutinin-I reacted with most receptor cells arranged mainly at the basal region of the olfactory epithelium. The olfactory nerve layer and glomerular layer of the main olfactory bulb were speckled with positive UEA-I staining, and positive fibers were scattered from the glomerular to the internal plexiform layer. The lateral olfactory tract and rostral migratory stream were also positive for UEA-I. We identified superficial short-axon cells, interneurons of the external plexiform layer, external, middle and internal tufted cells, mitral cells and granule cells as the origins of the UEA-I-positive fibers in the main olfactory bulb. The anterior olfactory nucleus, anterior piriform cortex and olfactory tubercle were negative for UEA-I. Most receptor cells in the vomeronasal epithelium and most glomeruli of the accessory olfactory bulb were positive for UEA-I. Our findings indicated that α1-2Fuc glycan is located within the primary and secondary, but not the ternary, pathways of the main olfactory system, in local circuits of the main olfactory bulb and within the primary, but not secondary, pathway of the vomeronasal system.

scholarly journals Dynamics of Olfactory Bulb Input and Output Activity During Odor Stimulation in Zebrafish

2004 ◽  
Vol 91 (6) ◽  
pp. 2658-2669 ◽  
Author(s):  
Rainer W. Friedrich ◽  
Gilles Laurent
Keyword(s):  
Olfactory Bulb ◽  
Activity Patterns ◽  
Odor Identification ◽  
Population Activity ◽  
Excitatory Response ◽  
Input And Output ◽  
Response Onset ◽  
Output Neurons ◽  
Response Profiles ◽  
Over Time

The processing of odor-evoked activity in the olfactory bulb (OB) of zebrafish was studied by extracellular single unit recordings from the input and output neurons, i.e., olfactory receptor neurons (ORNs) and mitral cells (MCs), respectively. A panel of 16 natural amino acid odors was used as stimuli. Responses of MCs, but not ORNs, changed profoundly during the first few hundred milliseconds after response onset. In MCs, but not ORNs, the total evoked excitatory activity in the population was initially odordependent but subsequently converged to a common level. Hence, the overall population activity is regulated by network interactions in the OB. The tuning widths of both ORN and MC response profiles were similar and, on average, stable over time. However, when analyzed for individual neurons, MC response profiles could sharpen (excitatory response to fewer odors) or broaden (excitatory response to more odors), whereas ORN response profiles remained nearly unchanged. Several observations indicate that dynamic inhibition plays an important role in this remodeling. Finally, the reliability of odor identification based on MC population activity patterns improved over time, whereas odor identification based on ORN activity patterns was most reliable early in the odor response. These results demonstrate that several properties of MC, but not ORN, activity change during the initial phase of the odor response with important consequences for odor-encoding activity patterns. Furthermore, our data indicate that inhibitory interactions in the OB are important in dynamically shaping the activity of OB output neurons.

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