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Short Communication

Exp Neurobiol 2020; 29(6): 425-432

Published online December 31, 2020

© The Korean Society for Brain and Neural Sciences

Multiplexed Processing of Vibrotactile Information in the Mouse Primary Somatosensory Cortex

Yoo Rim Kim1,2,3, Chang-Eop Kim1,4, Heera Yoon5, Sun Kwang Kim5,6* and Sang Jeong Kim1,2,3*

1Department of Physiology, Seoul National University College of Medicine, Seoul 08826, 2Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 08826, 3Neuroscience Research Institute, Seoul National University College of Medicine, Seoul 08826, 4Department of Physiology, College of Korean Medicine, Gachon University, Seongnam 13120, 5Department of Science in Korean Medicine, Graduate School, Kyung Hee University, Seoul 02447, 6Department of Physiology, College of Korean Medicine, Kyung Hee University, Seoul 02447, Korea

Correspondence to: *To whom correspondence should be addressed.
Sun Kwang Kim, TEL: 82-2-961-0323, FAX: 82-2-961-0333
Sang Jeong Kim, TEL: 82-2-740-8229, FAX: 82-2-763-9667

Received: August 31, 2020; Revised: October 24, 2020; Accepted: October 26, 2020

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

The primary somatosensory (S1) cortex plays a key role in distinguishing different sensory stimuli. Vibrotactile touch information is conveyed from the periphery to the S1 cortex through three major classes of mechanoreceptors: slowly adapting type 1 (SA1), rapidly adapting (RA), and Pacinian (PC) afferents. It has been a long-standing question whether specific populations in the S1 cortex preserve the peripheral segregation by the afferent submodalities. Here, we investigated whether S1 neurons exhibit specific responses to two distinct vibrotactile stimuli, which excite different types of mechanoreceptors (e.g., SA1 and PC afferents). Using in vivo two-photon microscopy and genetically encoded calcium indicator, GCaMP6s, we recorded calcium activities of S1 L2/3 neurons. At the same time, static (<1 Hz) and dynamic (150 Hz) vibrotactile stimuli, which are known to excite SA1 and PC, respectively, were pseudorandomly applied to the right hind paw in lightly anesthetized mice. We found that most active S1 neurons responded to both static and dynamic stimuli, but more than half of them showed preferred responses to either type of stimulus. Only a small fraction of the active neurons exhibited specific responses to either static or dynamic stimuli. However, the S1 population activity patterns by the two stimuli were markedly distinguished. These results indicate that the vibrotactile inputs driven by excitation of distinct submodalities are converged on the single cells of the S1 cortex, but are well discriminated by population activity patterns composed of neurons that have a weighted preference for each type of stimulus.

Graphical Abstract

Keywords: Vibrotactile, Mechanoreceptors, Primary somatosensory cortex, Two-photon imaging