Long-range functional loops in the mouse olfactory system and their roles in computing odor identity

Chae, Honggoo; Banerjee, Arkarup; Dussauze, Marie; Albeanu, Dinu F.

doi:10.1016/j.neuron.2022.09.005

Cited by 32 publications

(57 citation statements)

References 104 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Under this scenario, the low-gamma feedback inhibition is critical for segregating cell assemblies and generating a sparse, orthogonal odor representation. Concomitantly, the assembly recruitment would depend on OB projections determining which winner cells ‘escape’ gamma inhibition, highlighting the relevance of the OB-PCx interplay for olfaction ( Chae et al, 2022 ; Otazu et al, 2015 ). An important feature of the respiration-driven low-gamma oscillations is that the winners triggering them change according to odor context ( Figure 6A ), a process likely dependent on odor-encoding mitral cell assemblies from the OB ( Chae et al, 2022 ).…”

Section: Discussionmentioning

confidence: 99%

“…Concomitantly, the assembly recruitment would depend on OB projections determining which winner cells ‘escape’ gamma inhibition, highlighting the relevance of the OB-PCx interplay for olfaction ( Chae et al, 2022 ; Otazu et al, 2015 ). An important feature of the respiration-driven low-gamma oscillations is that the winners triggering them change according to odor context ( Figure 6A ), a process likely dependent on odor-encoding mitral cell assemblies from the OB ( Chae et al, 2022 ). Thus, the involvement of different cells and spiking dynamics would make the recruitment of feedback inhibition a non-homogenous process across respiration cycles, leading to small time jitters in peak gamma activity.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Mechanisms and functions of respiration-driven gamma oscillations in the primary olfactory cortex

González

Torterolo

Tort

2023

eLife

View full text Add to dashboard Cite

Gamma oscillations are believed to underlie cognitive processes by shaping the formation of transient neuronal partnerships on a millisecond scale. These oscillations are coupled to the phase of breathing cycles in several brain areas, possibly reflecting local computations driven by sensory inputs sampled at each breath. Here, we investigated the mechanisms and functions of gamma oscillations in the piriform (olfactory) cortex of awake mice to understand their dependence on breathing and how they relate to local spiking activity. Mechanistically, we find that respiration drives gamma oscillations in the piriform cortex, which correlate with local feedback inhibition and result from recurrent connections between local excitatory and inhibitory neuronal populations. Moreover, respiration-driven gamma oscillations are triggered by the activation of mitral/tufted cells in the olfactory bulb and are abolished during ketamine/xylazine anesthesia. Functionally, we demonstrate that they locally segregate neuronal assemblies through a winner-take-all computation leading to sparse odor coding during each breathing cycle. Our results shed new light on the mechanisms of gamma oscillations, bridging computation, cognition and physiology.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Mechanisms and functions of respiration-driven gamma oscillations in the primary olfactory cortex

González

Torterolo

Tort

2023

eLife

View full text Add to dashboard Cite

show abstract

“…3), differential impact on MCs and TCs could arise from differential intrinsic properties, local connectivity 80 , or odor response properties 70,81 . Alternatively, MCs and TCs, or the respective GC populations they connect to (superficial vs. deep GC), could be connected distinctly to GABAergic cortical neurons (different cortical regions preferentially targeting MCs versus TCs and/or different types of GCL GABAergic neurons) and could engage distinct functional loops with their respective cortical targets 82 . Either way, by separating TC population representation of different odors, GABAergic feedback stimulation can possibly enhance the discriminability capacity of a downstream decoder.…”

Section: Discussionmentioning

confidence: 99%

Long-range GABAergic projections contribute to cortical feedback control of sensory processing

et al. 2022

View full text Add to dashboard Cite

In the olfactory system, the olfactory cortex sends glutamatergic projections back to the first stage of olfactory processing, the olfactory bulb (OB). Such corticofugal excitatory circuits — a canonical circuit motif described in all sensory systems— dynamically adjust early sensory processing. Here, we uncover a corticofugal inhibitory feedback to OB, originating from a subpopulation of GABAergic neurons in the anterior olfactory cortex and innervating both local and output OB neurons. In vivo imaging and network modeling showed that optogenetic activation of cortical GABAergic projections drives a net subtractive inhibition of both spontaneous and odor-evoked activity in local as well as output neurons. In output neurons, stimulation of cortical GABAergic feedback enhances separation of population odor responses in tufted cells, but not mitral cells. Targeted pharmacogenetic silencing of cortical GABAergic axon terminals impaired discrimination of similar odor mixtures. Thus, corticofugal GABAergic projections represent an additional circuit motif in cortical feedback control of sensory processing.

show abstract

“…However, this theory has shortcomings because this separate representation of identity and concentration can be completely disrupted between different odors, causing some cells to switch their coding roles. Recent studies using demixed principal component analysis (PCA) have proposed that mitral cells primarily encode odor identity, whereas tufted cells could encode both odor identity and concentration ( 10 ). Additionally, while olfactory information in the glomerular layer is initially represented by a pattern of activated and inhibited glomeruli, recent studies have uncovered a more intricate intraglomerular coding system implying sister neurons, i.e.…”

Section: Main Textmentioning

confidence: 99%

Dynamic intraglomerular neuronal ensembles represent odor identity and concentration

Loizeau,

Angelova,

Cremer

et al. 2023

Preprint

View full text Add to dashboard Cite

The olfactory system has been extensively studied from an anatomical and functional point of view, yet how and where certain basic odor characteristics such as identity and concentration are represented in the brain remains poorly understood. The glomerular layer of the olfactory bulb is the first brain region that integrates olfactory signals and enables a topographic representation of odor identity. We investigated this odor encoding at the intraglomerular network level using genetic labeling, in vivo imaging, and computational methods. Our analyses demonstrated that glomerular glutamatergic neurons encode both odor identity and concentration. Furthermore, in vivo structural and functional imaging of sister neurons revealed the emergence of intraglomerular neuronal ensembles governed by odor identity and concentration. These findings revealed a novel network mechanism that enables the simultaneous coding of odor identity and concentration within glomerular modules, suggesting a potential mechanism for odor decorrelation and a new model for odor information processing in the olfactory bulb.One-sentence summaryUnraveling the scent puzzle: Discovery of intraglomerular neuronal ensembles sheds light on odor representation in the brain.

show abstract

Long-range functional loops in the mouse olfactory system and their roles in computing odor identity

Cited by 32 publications

References 104 publications

Mechanisms and functions of respiration-driven gamma oscillations in the primary olfactory cortex

Mechanisms and functions of respiration-driven gamma oscillations in the primary olfactory cortex

Long-range GABAergic projections contribute to cortical feedback control of sensory processing

Dynamic intraglomerular neuronal ensembles represent odor identity and concentration

Contact Info

Product

Resources

About