Investigation of cortical activity related to perception of tactile hardness

Stand-By Time

Tuesday, June 27, 2017: 12:45 PM  - 2:45 PM 

Submission No:

2153 

Submission Type:

Abstract Submission 

On Display:

Monday, June 26 & Tuesday, June 27 

Authors:

Jihyun Kim1, Yerin Park1, Jiwon Yeon1, Junsuk Kim2, Jang-Yeon Park3, Sung-Phil Kim1

Institutions:

1Ulsan National Institute of Science and Technology, Ulsan, Korea, Republic of, 2Max Planck Institute for Biological Cybernetics, Tuebingen, Germany, 3Sungkyunkwan University, Suwon, Korea, Republic of

First Author:

Jihyun Kim    -  Lecture Information | Contact Me
Ulsan National Institute of Science and Technology
Ulsan, Korea, Republic of

Introduction:

Tactile sensation is essential for humans to manipulate objects by hands. During object manipulation, many different physical properties of an object are sensed and processed by the human somatosensory system, supporting exquisite perceptual sensitivities [1]. Tactile sensation of different physical properties can be depicted in the several tactile perceptual dimensions, including roughness, hardness, stickiness and warmth [2]. To date, a number of human neuroimaging studies have unveiled neural mechanisms underlying roughness [3] and warmth perception [4]. Yet, relatively little is known about how the human brain subserves the perception of tactile hardness. Previous studies have suggested that slowly adapting type-1 (SA1) afferents are primarily responsible for perceiving hardness from the surface of an object [5] and the Brodmann areas (BA) 3b and 1 may contribute to perceiving hardness [6]. However, it remains elusive how the different levels of hardness are represented in the human brain during the dexterous manipulation of an object. Therefore, this study aims to investigate neural responses to tactile stimuli with the same shape and surface texture but different levels of hardness when people grip on the object with their hand. Functional magnetic resonance imaging (fMRI) is used to identify brain regions related with tactile hardness.

Methods:

Twelve right-handed subjects (8 female, mean age 23.1 years old) participated in the study. Experimental protocols were approved by the ethical committee of Ulsan National Institute of Science and Technology (UNISTIRB-15-16-A). Tactile stimuli with the same shape (oval) were prepared and grouped into four sets according to their hardness levels (level 1 to 4). Participants first performed a behavioral task in which they were given a pair of stimuli with eyes closed and asked to report the degree of a difference in hardness between them. Afterward, participants performed the fMRI experimental task in which they repetitively gripped on and released a given object (used in the behavioral task) for fifteen seconds followed by a nine-second rest. There were also trials in which participants executed the same grip-and-release motion without objects as a control task. Functional images (T2*-weighted gradient EPI, covering the whole depth of somatosensory area, TR = 3,000 ms, voxel size = 2.0 × 2.0 × 2.0 mm3) were obtained during the fMRI task using a Siemens 3T scanner (Magnetom TrioTim). The functional image analysis was performed using the general linear model (GLM) in SPM8 with a canonical hemodynamic response function to estimate blood-oxygen-level-dependent (BOLD) responses to each stimulus.

Results:

The analysis of behavioral experimental data showed that participants could correctly find differences in hardness levels among stimuli. The GLM analysis for individuals revealed activations in the contralateral postcentral gyrus in most participants modulated with different levels of hardness (p<0.001 uncorrected). Also, a random-effect group analysis of fMRI data revealed a cluster in the Rolandic operculum activated by the perception of tactile hardness (p<0.001 uncorrected). In addition, the cluster size and maximum activation peak was increased as the hardness level increased.

Conclusions:

Our study demonstrated that brain regions over the postcentral gyrus (S1) and Rolandic operculum might be related to the perception of tactile hardness. We also observed that the degree of activation in these regions, reflected by the size of the activated area (cluster size) and the level of activation (maximum peak) was proportional to the level of tactile hardness. Our results suggest that neural assemblies in the contralateral S1 and Roland operculum may play a role in sensing tactile hardness during dexterous object manipulation.

Imaging Methods:

BOLD fMRI 2

Perception and Attention:

Perception: Tactile/Somatosensory 1

Poster Session:

Poster Session - Tuesday

Keywords:

FUNCTIONAL MRI
Perception
Somatosensory
Touch

1|2Indicates the priority used for review

Would you accept an oral presentation if your abstract is selected for an oral session?

No

I would be willing to discuss my abstract with members of the press should my abstract be marked newsworthy:

Yes

Please indicate below if your study was a "resting state" or "task-activation” study.

Task-activation

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Healthy subjects only or patients (note that patient studies may also involve healthy subjects):

Healthy subjects

Internal Review Board (IRB) or Animal Use and Care Committee (AUCC) Approval. Please indicate approval below. Please note: Failure to have IRB or AUCC approval, if applicable will lead to automatic rejection of abstract.

Yes, I have IRB or AUCC approval

Please indicate which methods were used in your research:

Functional MRI

For human MRI, what field strength scanner do you use?

3.0T

Which processing packages did you use for your study?

SPM

Provide references in author date format

1. Skedung, L. et al. (2013), "Feeling small: Exploring the tactile perception limits," Scientific Reports, vol. 3, pp.1–6.
2. Tiest, W.M.B. (2010), "Tactual perception of material properties," Vision Research, vol. 50, no. 24, pp. 2775–2782
3. Kim, J. et al. (2015), "Decoding accuracy in supplementary motor cortex correlates with perceptual sensitivity to tactile roughness," PLoS ONE, vol. 10, no. 6, p.e0129777.
4. Olausson, H. et al. (2005), "Feelings of warmth correlate with neural activity in right anterior insular cortex," Neuroscience Letters, vol. 389, no. 1, pp. 1–5.
5. Srinivasan, M.A. & LaMotte, R.H. (1995), "Tactual discrimination of softness," Journal of Neurophysiology, vol. 73, no. 1, pp. 88–101.
6. Servos, P. et al. (2001), "fMRI-derived cortical maps for haptic shape, texture, and hardness," Cognitive Brain Research, vol. 12, no. 2, pp. 307–313.