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Updated: Sep 6, 2025
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Cheek Injection Model for Simultaneous Measurement of Pain and Itch-related Behaviors
Published on: September 27, 2019
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Itch perception is reflected by neuronal ignition in the primary somatosensory cortex
Xiao-Jun Chen1, Yan-He Liu1, Ning-Long Xu1
1Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China.
National Science Review
|June 30, 2022
Summary
Researchers identified specific neurons in the primary somatosensory cortex (S1) that encode itch perception. This discovery advances understanding of how the brain processes itch signals and motivates further study of neural coding.
Area of Science:
- Neuroscience
- Sensory Processing
Background:
- Itch signal processing involves multiple cortical areas, including the primary somatosensory cortex (S1).
- The specific cortical representation of itch perception remains largely unknown.
Purpose of the Study:
- To investigate the neural coding of itch perception within the primary somatosensory cortex (S1).
- To elucidate the role of S1 in processing itch signals and driving scratching behavior.
Main Methods:
- Utilized novel miniature two-photon microscopic imaging in freely moving mice.
- Employed pharmacological inactivation of S1 to assess its role in itch behavior.
- Developed an optogenetics-based paradigm for precise pruritic stimulation.
- Recorded neuronal activity in S1 during itch perception.
Main Results:
- Pharmacological inactivation of S1 abolished itch-induced scratching behavior.
- Activity of a subset of layer 2/3 pyramidal neurons in S1 predicted scratching behavior.
- A small fraction of S1 neurons displayed an "ignition-like" firing pattern at the itch detection threshold.
Conclusions:
- A subpopulation of S1 pyramidal neurons encodes itch perception, driving subsequent scratching.
- Identified a neural mechanism for itch perceptual coding in S1 at the single-neuron level.
- This research provides a foundation for studying itch perception in freely moving animals.
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