Multiplexed Processing of Vibrotactile Information in the Mouse Primary Somatosensory Cortex

다국어 초록 (Multilingual Abstract)

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.

참고문헌 (Reference)

1 Yamins DL, "Using goal-driven deep learning models to understand sensory cortex" 19 : 356-365, 2016

2 Roudaut Y, "Touch sense : functional organization and molecular determinants of mechanosensitive receptors" 6 : 234-245, 2012

3 Saal HP, "Touch is a team effort : interplay of submodalities in cutaneous sensibility" 37 : 689-697, 2014

4 Johnson KO, "The roles and functions of cutaneous mechanoreceptors" 11 : 455-461, 2001

5 Sakurai K, "The organization of submodality-specific touch afferent inputs in the vibrissa column" 5 : 87-98, 2013

6 Garion L, "Texture coarseness responsive neurons and their mapping in layer 2-3 of the rat barrel cortex in vivo" 3 : e03405-, 2014

7 Dykes RW, "Submodality segregation and receptive-field sequences in cuneate, gracile, and external cuneate nuclei of the cat" 47 : 389-416, 1982

8 Pei YC, "Shape invariant coding of motion direction in somatosensory cortex" 8 : e1000305-, 2010

9 Ochoa J, "Sensations evoked by intraneural microstimulation of single mechanoreceptor units innervating the human hand" 342 : 633-654, 1983

10 Kim YR, "S1 employs feature-dependent differential selectivity of single cells and distributed patterns of populations to encode mechanosensations" 13 : 132-, 2019

11 Johansson RS, "Responses of mechanoreceptive afferent units in the glabrous skin of the human hand to sinusoidal skin displacements" 244 : 17-25, 1982

12 Stettler DD, "Representations of odor in the piriform cortex" 63 : 854-864, 2009

13 Dykes RW, "Regional segregation of neurons responding to quickly adapting, slowly adapting, deep and Pacinian receptors within thalamic ventroposterior lateral and ventroposterior inferior nuclei in the squirrel monkey(Saimiri sciureus)" 6 : 1687-1692, 1981

14 Saal HP, "Rate and timing of cortical responses driven by separate sensory channels" 4 : e10450-, 2015

15 Dépeault A, "Neuronal correlates of tactile speed in primary somatosensory cortex" 110 : 1554-1566, 2013

16 Johnson KO, "Neural mechanisms of tactual form and texture perception" 15 : 227-250, 1992

17 Harvey MA, "Multiplexing stimulus information through rate and temporal codes in primate somatosensory cortex" 11 : e1001558-, 2013

18 Delmas P, "Molecular mechanisms of mechanotransduction in mammalian sensory neurons" 12 : 139-153, 2011

19 Sur M, "Modular segregation of functional cell classes within the postcentral somatosensory cortex of monkeys" 212 : 1059-1061, 1981

20 Sur M, "Modular distribution of neurons with slowly adapting and rapidly adapting responses in area 3b of somatosensory cortex in monkeys" 51 : 724-744, 1984

21 Mountcastle VB, "Modality and topographic properties of single neurons of cat's somatic sensory cortex" 20 : 408-434, 1957

22 Rothschild G, "Functional organization and population dynamics in the mouse primary auditory cortex" 13 : 353-360, 2010

23 Pei YC, "Convergence of submodality-specific input onto neurons in primary somatosensory cortex" 102 : 1843-1853, 2009

24 Zuo Y, "Complementary contributions of spike timing and spike rate to perceptual decisions in rat S1 and S2 cortex" 25 : 357-363, 2015

25 Chen X, "A gustotopic map of taste qualities in the mammalian brain" 333 : 1262-1266, 2011