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Updated: May 31, 2026
11:08
Recording Temperature-induced Neuronal Activity through Monitoring Calcium Changes in the Olfactory Bulb of Xenopus laevis
Published on: June 3, 2016
Monosynaptic and polysynaptic feed-forward inputs to mitral cells from olfactory sensory neurons
Marion Najac1, Didier De Saint Jan, Leire Reguero
1Institut National de la Santé et de la Recherche Médicale Unité 603, Paris, France.
Summary
Olfactory sensory neurons (OSNs) directly activate mitral cells, but their response is also shaped by complex intraglomerular feedforward excitation and inhibition. This study clarifies synaptic mechanisms in olfactory processing.
Area of Science:
- Neuroscience
- Olfactory System Research
- Synaptic Transmission
Background:
- Olfactory sensory neurons (OSNs) expressing the same odorant receptor converge in olfactory bulb glomeruli.
- The precise synaptic mechanisms governing mitral cell activation remain debated.
Purpose of the Study:
- To investigate the synaptic mechanisms underlying mitral cell activation by olfactory sensory neurons.
- To elucidate the roles of direct OSN input and intraglomerular circuitry in shaping mitral cell responses.
Main Methods:
- Patch-clamp recordings were performed in mouse olfactory bulb slices.
- Stimulation of olfactory sensory neuron afferent fibers was used to evoke postsynaptic responses.
Main Results:
- OSN stimulation evoked a biphasic postsynaptic response in mitral cells: a fast monosynaptic component and a slower feedforward excitation.
- Feedforward inhibition was also triggered by OSN stimulation, modulating feedforward excitation but not the monosynaptic component.
- The fast monosynaptic input was sometimes absent when fewer OSN afferents were stimulated.
Conclusions:
- Direct synaptic connections between OSNs and mitral cells exist and contribute to mitral cell activation.
- Intraglomerular feedforward pathways, involving dendro-dendritic interactions, play a significant role in shaping mitral cell responses.
- Both feedforward excitation and inhibition are crucial for regulating mitral cell activity in the olfactory bulb.
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