scholarly journals Greater excitability and firing irregularity of tufted cells underlies distinct afferent‐evoked activity of olfactory bulb mitral and tufted cells

2014 ◽  
Vol 592 (10) ◽  
pp. 2097-2118 ◽  
Author(s):  
Shawn D. Burton ◽  
Nathaniel N. Urban
Keyword(s):  
Olfactory Bulb ◽  
Tufted Cells ◽  
Evoked Activity ◽  
Firing Irregularity

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

2020 ◽  
Author(s):  
Camille Mazo ◽  
Soham Saha ◽  
Antoine Nissant ◽  
Enzo Peroni ◽  
Pierre-Marie Lledo ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Long Range ◽  
Sensory Processing ◽  
Somatosensory System ◽  
Sensory Systems ◽  
Projection Neurons ◽  
Inhibitory Feedback ◽  
Thalamic Projections ◽  
Tufted Cells ◽  
Evoked Activity

AbstractIn sensory systems, cortical areas send excitatory projections back to subcortical areas to dynamically adjust sensory processing. Here, we uncover for the first time the existence of a cortical inhibitory feedback to subcortical sensory areas. Investigating the olfactory system, we reveal that a subpopulation of GABAergic neurons in the anterior olfactory cortex target the olfactory bulb. Analogous inhibitory cortico-thalamic projections were also present in the somatosensory system. Long-range inhibitory inputs synapsed with both local and output neurons of the olfactory bulb. At the functional level, optogenetic activation of cortical GABAergic projections caused a net subtractive inhibition of both spontaneous and odor-evoked activity in local as well as output projection neurons, mitral and tufted cells. In tufted cells, but not mitral cells, this resulted in an enhanced separation of population odor responses. Furthermore, GABAergic corticofugal projections entrained network oscillations in the communication band between the cortex and the olfactory bulb. Targeted pharmacogenetic silencing of the cortical GABAergic outputs in the olfactory bulb impaired discrimination of similar odor mixtures. Thus, cortical GABAergic feedback represents a new circuit motif in sensory systems involved in refining sensory processing and perception.

Mitral and Tufted Cells Differ in the Decoding Manner of Odor Maps in the Rat Olfactory Bulb

2004 ◽  
Vol 91 (6) ◽  
pp. 2532-2540 ◽  
Author(s):  
Shin Nagayama ◽  
Yuji K. Takahashi ◽  
Yoshihiro Yoshihara ◽  
Kensaku Mori
Keyword(s):  
Olfactory Bulb ◽  
Spike Activity ◽  
Homologous Series ◽  
Morphological Difference ◽  
Aliphatic Acid ◽  
Mitral Cells ◽  
Firing Rates ◽  
Aliphatic Acids ◽  
Projection Pattern ◽  
Tufted Cells

Mitral and tufted cells in the mammalian olfactory bulb are principal neurons, each type having distinct projection pattern of their dendrites and axons. The morphological difference suggests that mitral and tufted cells are functionally distinct and may process different aspects of olfactory information. To examine this possibility, we recorded odorant-evoked spike responses from mitral and middle tufted cells in the aliphatic acid- and aldehyde-responsive cluster at the dorsomedial part of the rat olfactory bulb. Homologous series of aliphatic acids and aldehydes were used for odorant stimulation. In response to adequate odorants, mitral cells showed spike responses with relatively low firing rates, whereas middle tufted cells responded with higher firing rates. Examination of the molecular receptive range (MRR) indicated that most mitral cells exhibited a robust inhibitory MRR, whereas a majority of middle tufted cells showed no or only a weak inhibitory MRR. In addition, structurally different odorants that activated neighboring clusters inhibited the spike activity of mitral cells, whereas they caused no or only a weak inhibition in the middle tufted cells. Furthermore, responses of mitral cells to an adequate excitatory odorant were greatly inhibited by mixing the odorant with other odorants that activated neighboring glomeruli. In contrast, odorants that activated neighboring glomeruli did not significantly inhibit the responses of middle tufted cells to the adequate excitatory odorant. These results indicate a clear difference between mitral and middle tufted cells in the manner of decoding the glomerular odor maps.

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

scholarly journals External Tufted Cells Drive the Output of Olfactory Bulb Glomeruli

2009 ◽  
Vol 29 (7) ◽  
pp. 2043-2052 ◽  
Author(s):  
D. De Saint Jan ◽  
D. Hirnet ◽  
G. L. Westbrook ◽  
S. Charpak
Keyword(s):  
Olfactory Bulb ◽  
Tufted Cells

scholarly journals Cellular and Synaptic Mechanisms That Differentiate Mitral Cells and Superficial Tufted Cells Into Parallel Output Channels in the Olfactory Bulb

2020 ◽  
Vol 14 ◽  
Author(s):  
Shelly Jones ◽  
Joel Zylberberg ◽  
Nathan Schoppa
Keyword(s):  
Olfactory Bulb ◽  
Plexiform Layer ◽  
Input Resistance ◽  
Cell Types ◽  
Mitral Cells ◽  
Whole Cell ◽  
Wide Range ◽  
Tufted Cells ◽  
Parallel Output

A common feature of the primary processing structures of sensory systems is the presence of parallel output “channels” that convey different information about a stimulus. In the mammalian olfactory bulb, this is reflected in the mitral cells (MCs) and tufted cells (TCs) that have differing sensitivities to odors, with TCs being more sensitive than MCs. In this study, we examined potential mechanisms underlying the different responses of MCs vs. TCs. For TCs, we focused on superficial TCs (sTCs), which are a population of output TCs that reside in the superficial-most portion of the external plexiform layer, along with external tufted cells (eTCs), which are glutamatergic interneurons in the glomerular layer. Using whole-cell patch-clamp recordings in mouse bulb slices, we first measured excitatory currents in MCs, sTCs, and eTCs following olfactory sensory neuron (OSN) stimulation, separating the responses into a fast, monosynaptic component reflecting direct inputs from OSNs and a prolonged component partially reflecting eTC-mediated feedforward excitation. Responses were measured to a wide range of OSN stimulation intensities, simulating the different levels of OSN activity that would be expected to be produced by varying odor concentrations in vivo. Over a range of stimulation intensities, we found that the monosynaptic current varied significantly between the cell types, in the order of eTC > sTC > MC. The prolonged component was smaller in sTCs vs. both MCs and eTCs. sTCs also had much higher whole-cell input resistances than MCs, reflecting their smaller size and greater membrane resistivity. To evaluate how these different electrophysiological aspects contributed to spiking of the output MCs and sTCs, we used computational modeling. By exchanging the different cell properties in our modeled MCs and sTCs, we could evaluate each property's contribution to spiking differences between these cell types. This analysis suggested that the higher sensitivity of spiking in sTCs vs. MCs reflected both their larger monosynaptic OSN signal as well as their higher input resistance, while their smaller prolonged currents had a modest opposing effect. Taken together, our results indicate that both synaptic and intrinsic cellular features contribute to the production of parallel output channels in the olfactory bulb.

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