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In vivo Imaging of Optic Nerve Fiber Integrity by Contrast-Enhanced MRI in Mice
Published on: July 22, 2014
Octopaminergic modulation of contrast sensitivity.
Roel de Haan1, Yu-Jen Lee, Karin Nordström
1Department of Neuroscience, Uppsala University Uppsala, Sweden.
Frontiers in Integrative Neuroscience
|August 10, 2012
Summary
Insect flight and octopamine primarily influence motion vision adaptation presynaptically, affecting elementary motion detectors (EMDs). Postsynaptic effects on lobula plate tangential cells (LPTCs) play a minimal role in this adaptation process.
Area of Science:
- Neuroscience
- Sensory Systems
- Insect Vision
Background:
- Sensory systems adapt to prolonged stimulation by reducing responses.
- Behavioral state influences neural responses in motion vision.
- Octopamine release during insect flight impacts neural processing.
Purpose of the Study:
- Investigate presynaptic vs. postsynaptic effects of activity on motion adaptation.
- Determine the role of octopamine in motion vision adaptation.
- Elucidate the mechanisms underlying changes in lobula plate tangential cells (LPTCs).
Main Methods:
- Intracellular recordings of Eristalis horizontal system (HS) neurons.
- Construction of contrast response functions before and after adaptation.
- Application of octopamine receptor agonist chlordimeform (CDM).
Main Results:
- Identified three motion adaptation components, two likely presynaptic and one postsynaptic.
- CDM affected early, EMD-associated contrast gain reduction, dependent on temporal frequency.
- CDM-induced changes in HS membrane conductance diminished during/after visual stimulation.
Conclusions:
- Physical activity primarily impacts motion adaptation presynaptically, at the level of elementary motion detectors (EMDs).
- Post-EMD effects, such as changes in membrane conductance, have a minimal role in activity-induced motion adaptation.
- Findings clarify the neural basis of behavioral state modulation in visual processing.
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