Neural circuits of the mammalian main olfactory bulb

Burton, Shawn D.; Lepousez, Gabriel; Lledo, Pierre−Marie; Wachowiak, Matt

doi:10.1016/b978-0-12-814411-4.00001-9

“…In CA1, however, fast-and slow-gamma-frequency synchronization of principal cells is driven extrinsically by shifting communication between medial entorhinal cortex and hippocampal CA3, respectively (Colgin et al, 2009), while our results in the MOB instead point toward differential synchronization of complementary cell types receiving common inputs. These differences notwithstanding, leading hypotheses respectively associate fast-vs. slow-gammafrequency oscillations in CA1 with the encoding of current spatial information vs. spatial memory retrieval (Colgin, 2015), functions provocatively similar to burgeoning evidence respectively linking TC vs. MC activity to the encoding of current olfactory surroundings vs. learned olfactory context (Burton et al, 2020). This potential functional correspondence between fast-and slow-gammafrequency oscillations of the MOB and hippocampus, while speculative, warrants further investigation.…”

Section: Discussionmentioning

confidence: 72%

“…First, whether and how tufted cells (TCs) synchronize their firing has not been tested. Overwhelming evidence has established that TCs, a second type of excitatory MOB principal cell, differ from MCs in their intrinsic and synaptic properties, sensory responses, and axonal projections (Shepherd et al, 2004;Nagayama et al, 2014;Burton et al, 2020). Not only do these findings support a model in which TCs and MCs form parallel pathways encoding complementary information, but they further suggest that TCs and MCs may differentially engage in fast network oscillations.…”

Section: Introductionmentioning

confidence: 96%

Cell and circuit origins of fast network oscillations in the mammalian main olfactory bulb

Burton

¹

,

Urban

²

2021

eLife

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Neural synchrony generates fast network oscillations throughout the brain, including the main olfactory bulb (MOB), the first processing station of the olfactory system. Identifying the mechanisms synchronizing neurons in the MOB will be key to understanding how network oscillations support the coding of a high-dimensional sensory space. Here, using paired recordings and optogenetic activation of glomerular sensory inputs in MOB slices, we uncovered profound differences in principal mitral cell (MC) vs. tufted cell (TC) spike-time synchrony: TCs robustly synchronized across fast- and slow-gamma frequencies, while MC synchrony was weaker and concentrated in slow-gamma frequencies. Synchrony among both cell types was enhanced by shared glomerular input but was independent of intraglomerular lateral excitation. Cell-type differences in synchrony could also not be traced to any difference in the synchronization of synaptic inhibition. Instead, greater TC than MC synchrony paralleled the more periodic firing among resonant TCs than MCs and emerged in patterns consistent with densely synchronous network oscillations. Collectively, our results thus reveal a mechanism for parallel processing of sensory information in the MOB via differential TC vs. MC synchrony, and further contrast mechanisms driving fast network oscillations in the MOB from those driving the sparse synchronization of irregularly-firing principal cells throughout cortex.

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“…The cellular composition and synaptic connectivity of the rodent OB are reasonably well established (for review see Burton et al 2020;Nagayama et al 2014;Wachowiak and Shipley 2006), a prerequisite of understanding neuromodulatory effects. We want to briefly introduce the anatomy of the OB and mention cell types that have been shown to play a role as effectors of extrinsic neuromodulation.…”

Section: Neuroanatomy Of the Vertebrate Olfactory Bulbmentioning

confidence: 99%

Extrinsic neuromodulation in the rodent olfactory bulb

Brunert

¹

,

Rothermel

²

2020

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Evolutionarily, olfaction is one of the oldest senses and pivotal for an individual’s health and survival. The olfactory bulb (OB), as the first olfactory relay station in the brain, is known to heavily process sensory information. To adapt to an animal’s needs, OB activity can be influenced by many factors either from within (intrinsic neuromodulation) or outside (extrinsic neuromodulation) the OB which include neurotransmitters, neuromodulators, hormones, and neuropeptides. Extrinsic sources seem to be of special importance as the OB receives massive efferent input from numerous brain centers even outweighing the sensory input from the nose. Here, we review neuromodulatory processes in the rodent OB from such extrinsic sources. We will discuss extrinsic neuromodulation according to points of origin, receptors involved, affected circuits, and changes in behavior. In the end, we give a brief outlook on potential future directions in research on neuromodulation in the OB.

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“…In CA1, however, fast-and slow-gamma-frequency synchronization of principal cells is driven extrinsically by shifting communication between medial entorhinal cortex and hippocampal CA3, respectively (Colgin et al, 2009), while our results in the MOB instead point toward differential synchronization of complementary cell types receiving common inputs. These differences notwithstanding, leading hypotheses respectively associate fast-vs. slow-gamma-frequency oscillations in CA1 with the encoding of current spatial information vs. spatial memory retrieval (Colgin, 2015), functions provocatively similar to burgeoning evidence respectively linking TC vs. MC activity to the encoding of current olfactory surroundings vs. learned olfactory context (Burton et al, 2020). This potential functional correspondence between fast-and slow-gamma-frequency oscillations of the MOB and hippocampus, while speculative, warrants further investigation.…”

Section: Fast-and Slow-gamma-frequency Synchrony In the Mobmentioning

confidence: 73%

Cell and circuit origins of fast network oscillations in the mammalian main olfactory bulb

Burton

¹

,

Urban²

2021

Preprint

0

View full text Add to dashboard Cite

Neural synchrony generates fast network oscillations throughout the brain, including the main olfactory bulb (MOB), the first processing station of the olfactory system. Identifying the mechanisms synchronizing neurons in the MOB will be key to understanding how network oscillations support the coding of a high-dimensional sensory space. Here, using paired recordings and optogenetic activation of glomerular sensory inputs in MOB slices, we uncovered profound differences in principal mitral cell (MC) vs. tufted cell (TC) spike-time synchrony: TCs robustly synchronized across fast- and slow-gamma frequencies, while MC synchrony was weaker and concentrated in slow-gamma frequencies. Synchrony among both cell types was enhanced by shared glomerular input but was independent of intraglomerular lateral excitation. Cell-type differences in synchrony could also not be traced to any difference in the synchronization of synaptic inhibition. Instead, greater TC than MC synchrony paralleled the more periodic firing among resonant TCs than MCs and emerged in patterns consistent with densely synchronous network oscillations. Collectively, our results thus reveal a mechanism for parallel processing of sensory information in the MOB via differential TC vs. MC synchrony, and further contrast mechanisms driving fast network oscillations in the MOB from those driving the sparse synchronization of irregularly-firing principal cells throughout cortex.

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Neural circuits of the mammalian main olfactory bulb

Cited by 4 publications

References 161 publications

Cell and circuit origins of fast network oscillations in the mammalian main olfactory bulb

Cell and circuit origins of fast network oscillations in the mammalian main olfactory bulb

Extrinsic neuromodulation in the rodent olfactory bulb

Cell and circuit origins of fast network oscillations in the mammalian main olfactory bulb

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