Related Experiment Videos
Lateral excitation within the olfactory bulb.
Jason M Christie1, Gary L Westbrook
1Vollum Institute, Oregon Health and Science University, Portland, Oregon 97239, USA. christij@ohsu.edu
Summary
Lateral excitation in the olfactory bulb enhances coordinated activity. Electrical coupling and glutamate spillover amplify sensory input sensitivity within glomeruli.
Area of Science:
- Neuroscience
- Olfactory system research
Background:
- Lateral inhibition is common in cortical networks for contrast enhancement.
- In the olfactory bulb, inhibition occurs via mitral cell and interneuron synapses.
- Lateral excitatory interactions between mitral cells are less recognized but enhance coordinated activity.
Purpose of the Study:
- To investigate lateral excitation between mitral cells in the olfactory bulb.
- To understand the mechanisms underlying lateral excitation in olfactory glomeruli.
Main Methods:
- Paired recordings between mitral cells projecting to the same glomerulus.
- Experiments using connexin36 knockout mice lacking mitral-mitral cell gap junctions.
- Investigating the role of glutamate spillover and uptake blockade.
Main Results:
- Trains of action potentials in one mitral cell induced autoexcitation and depolarization in a second cell.
- Lateral excitation was absent in mice lacking mitral-mitral cell gap junctions.
- Glutamate spillover contributed to lateral excitation, especially during high activity or blocked uptake.
Conclusions:
- Electrical coupling via gap junctions and glutamate spillover form a lateral excitatory network in olfactory glomeruli.
- This network significantly amplifies the sensitivity of glomeruli to sensory input.
- Lateral excitation plays a crucial role in olfactory processing and sensory information amplification.