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Selective suppression of horizontal propagation in rat visual cortex by norepinephrine
M Kobayashi1, K Imamura, T Sugai
1Department of Neuroscience, Osaka Bioscience Institute, 6-2-4 Furuedai, Suita-shi, Osaka 565-0874, Japan.
The European Journal of Neuroscience
|January 29, 2000
Summary
Norepinephrine, released in the brain, suppresses horizontal signal spread in the visual cortex. This action, by altering neural transmission, may underlie how attention restructures visual processing.
Area of Science:
- Neuroscience
- Visual Cortex Research
Background:
- Norepinephrine (NE) from locus coeruleus neurons influences attention.
- NE's effect on cortical neurons is diverse and not fully understood.
- Its impact on large-scale excitatory propagation in the visual cortex remains unclear.
Purpose of the Study:
- To investigate how widespread norepinephrine application affects excitatory propagation in the visual cortex.
- To elucidate the specific mechanisms of norepinephrine's action on neural transmission in visual cortical layers.
Main Methods:
- Utilized optical imaging techniques on rat visuocortical slices.
- Employed multi-site field potential recordings using a multi-electrode dish.
- Conducted electrophysiological recordings to analyze neural transmission.
Main Results:
- Identified a novel action of norepinephrine: prominent suppression of horizontal propagation in visual cortex layers II/III.
- Confirmed this suppression using multi-electrode field potential recordings.
- Electrophysiology revealed NE suppresses excitatory and enhances inhibitory transmission to pyramidal neurons.
Conclusions:
- Norepinephrine significantly modulates visual cortical circuitry by inhibiting horizontal signal spread.
- This action, involving altered synaptic transmission, may contribute to the neural basis of visual attention.
- State-dependent restructuring of receptive fields via NE could be a mechanism for attention-modulated visual processing.