Mosaic representations of odors in the input and output layers of the mouse olfactory bulb

Chae, Honggoo; Kepple, Daniel; Bast, Walter Germán; Murthy, Venkatesh N.; Koulakov, Alexei A.; Albeanu, Dinu F.

doi:10.1038/s41593-019-0442-z

Cited by 37 publications

(61 citation statements)

References 60 publications

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“…Within the mouse OB, these axons are organized into thousands of discrete and spatially organized information channels called glomeruli, each of which represents the tuning properties of an individual odor receptor 11 . Odor information is reformatted by OB circuits before being transmitted to cortex; it is not clear whether or to what degree this peripheral transformation preserves information about odor chemical relationships 12 – 14 .…”

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confidence: 99%

Structure and flexibility in cortical representations of odour space

Pashkovski

Iurilli

Brann

et al. 2020

Nature

146

158

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The cortex organizes sensory information to enable discrimination and generalization 1 – 4 . Systematic representations of chemical odor space have not been described in olfactory cortex, and so it remains unclear how odor relationships are encoded to place chemically distinct but similar odors, like lemon and orange, into perceptual categories, like citrus 5 – 7 . Here we demonstrate that both the piriform cortex (PCx) and its sensory inputs from the olfactory bulb represent chemical odor relationships through correlated patterns of activity. However, cortical odor codes differ from those in the bulb: cortex more strongly clusters together representations for related odors, selectively rewrites pairwise odor relationships, and better matches odor perception. The bulb-to-cortex transformation depends upon the associative network originating within PCx, and can be reshaped by passive odor experience. Thus, cortex actively builds a structured representation of chemical odor space that highlights odor relationships; this representation is similar across individuals but remains plastic, suggesting a means through which the olfactory system can assign related odor cues to common and yet personalized percepts.

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confidence: 99%

Structure and flexibility in cortical representations of odour space

Pashkovski

Iurilli

Brann

et al. 2020

Nature

146

158

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“…Upon spiking (global or regional) the spikes will result in GABA release not only at the reciprocal synapses that have received input from an active glomerulus but also in GABA release from other spines invaded by the spike that connect to extra-glomerular mitral cells, exerting lateral inhibition. The spatial structure of this lateral inhibition depends on anatomical connectivity and network dynamics and has been proposed to be either isotropic, consistent with a center-surround field as in the retina, or rather patchy (reviewed in Murthy 2011; see also Chae et al 2019). Note however, that most of the involved studies did not investigate specifically GC-mediated lateral inhibition.…”

Section: Right: Recording Situation For Connection Gc→mc a Gc Actionmentioning

confidence: 99%

Presynaptic NMDA receptors cooperate with local action potentials to implement activity-dependent GABA release from the reciprocal olfactory bulb granule cell spine

Lage-Rupprecht

Zhou

Bianchini

et al. 2018

Preprint

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AbstractIn the rodent olfactory bulb the smooth dendrites of the principal glutamatergic mitral cells (MCs) form reciprocal dendrodendritic synapses with large spines on GABAergic granule cells (GC), where unitary release of glutamate can trigger postsynaptic local activation of voltage-gated Na+-channels (Navs), i.e. a spine spike. Can such single MC inputs evoke reciprocal release? We find that unitary-like activation via two-photon uncaging of glutamate causes GC spines to release GABA both synchronously and asynchronously onto MC dendrites. This release indeed requires activation of Navs and high-voltage-activated Ca2+-channels (HVACCs), but also of NMDA receptors (NMDAR). Simulations show temporally overlapping HVACC- and NMDAR-mediated Ca2+-currents during the spine spike, and ultrastructural data prove NMDAR presence within the GABAergic presynapse. The cooperative action of presynaptic NMDARs allows to implement synapse-specific, activity-dependent and non-topographical lateral inhibition and thus could provide an efficient solution to combinatorial percept synthesis in a sensory system with many receptor channels.

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“…As shown in Figure 6D, for proficient animals licking differs between odorants within 675 about 0.5 seconds from stimulus onset, at the same time that PRP decoding becomes 676 significant. This is slower than discrimination times for odorant responses recorded in 677 mice performing two alternative forced choice odorant discrimination or receiving odors 678 passively where discrimination takes place within the first respiratory cycle (~250 ms) high dimensionality to downstream brain processing areas (Chae et al, 2019). 735…”

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confidence: 95%

Learning improves decoding of odor identity with phase-referenced oscillations in the olfactory bulb

Losacco

Ramirez-Gordillo

Gilmer

et al. 2019

Preprint

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Local field potential oscillations reflect temporally coordinated neuronal ensembles— coupling distant brain regions, gating processing windows, and providing a reference for spike timing-based codes. In phase amplitude coupling (PAC), the amplitude of the envelope of a faster oscillation is larger within a phase window of a slower carrier wave. Here, we characterized PAC, and the related theta phase-referenced high gamma and beta power (PRP), in the olfactory bulb of mice learning to discriminate odorants. PAC changes throughout learning, and odorant-elicited changes in PRP increase for rewarded and decrease for unrewarded odorants. Contextual odorant identity (is the odorant rewarded?) can be decoded from peak PRP in animals proficient in odorant discrimination, but not in naïve mice. As the animal learns to discriminate the odorants the dimensionality of PRP decreases. Therefore, modulation of phase-referenced chunking of information in the course of learning plays a role in early sensory processing in olfaction.SignificanceEarly processing of olfactory information takes place in circuits undergoing slow frequency theta oscillations generated by the interplay of olfactory input modulated by sniffing and centrifugal feedback from downstream brain areas. Studies in the hippocampus and cortex suggest that different information “chunks” are conveyed at different phases of the theta oscillation. Here we show that in the olfactory bulb, the first processing station in the olfactory system, the amplitude of high frequency gamma oscillations encodes for information on whether an odorant is rewarded when it is observed at the peak phase of the theta oscillation. Furthermore, encoding of information by the theta phase-referenced gamma oscillations becomes more accurate as the animal learns to differentiate two odorants.

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Mosaic representations of odors in the input and output layers of the mouse olfactory bulb

Cited by 37 publications

References 60 publications

Structure and flexibility in cortical representations of odour space

Structure and flexibility in cortical representations of odour space

Presynaptic NMDA receptors cooperate with local action potentials to implement activity-dependent GABA release from the reciprocal olfactory bulb granule cell spine

Learning improves decoding of odor identity with phase-referenced oscillations in the olfactory bulb

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