1
|
CHOI MIHYUN, KIM HYUNGSIK, JO JIHUN, KIM JISUN, JUN JAEHOON, PARK JONGRAK, CHUNG SOONCHEOL. INTERACTION EFFECT BETWEEN BEAM DIAMETER AND ENERGY DENSITY IN LASER-INDUCED TACTILE PERCEPTION. J MECH MED BIOL 2018. [DOI: 10.1142/s0219519418400110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This study aims to investigate the interaction effect between the beam diameter and energy density, which are perceived as laser-induced tactile perception by humans, by diversely varying the laser parameters, beam diameter, and energy. Eight healthy male college students of 23.5[Formula: see text][Formula: see text][Formula: see text]1.7 years participated in the study. The range of the beam diameter of the displayed laser stimulation was between 0.03[Formula: see text]mm and 8[Formula: see text]mm, and a total of 21 sizes were displayed. The laser energy was sequentially displayed from the minimum energy that can be displayed by one beam diameter to the maximum energy range that does not exceed the maximum permissible exposure (MPE) level since the energy varies according to the beam diameter. The laser energy was controlled by an optical density ([Formula: see text]) filter and was measured by an optical power meter (energy meter). Furthermore, the beam diameter was adjusted by moving the lens, which was confirmed with the beam profiler. The experimental test consists of the control phase (19[Formula: see text]s), stimulus phase (7[Formula: see text]s), and response phase (4[Formula: see text]s); the total duration of the test was 30[Formula: see text]s. The stimulus phase is the period in which stimulation was displayed on the skin through laser irradiation, and the stimulation was displayed by changing the beam diameter and the energy from the laser. The total number of beam diameter and energy pairs displayed to the subjects was 113 and 5 trials of irradiation were conducted for each pair. Stimulation perception response was recorded by pressing the response buttons during the response phase, and the responses were predefined as “no feeling,” “tactile sensation”, and “pain.” Through the extracted response data from the response phase, the beam diameter and energy density pair in which more than 50% of the subjects responded as having perceived tactile sensation were selected from the possible laser energy that could be displayed from one beam diameter. The simulation results showed that increasing the beam diameter increased the penetration depth, indicating an effective energy transfer to the skin. Therefore, increasing the beam diameter results in increased scattering, and hence increased penetration depth, and ultimately a more effective energy transfer. Therefore, increased beam diameter results in higher energy transfer efficiency, indicating that the required energy density by more than 50% of the subjects to perceive tactile sensation decreased.
Collapse
Affiliation(s)
- MI-HYUN CHOI
- Biomedical Engineering, BK21+ Research Institute of Biomedical Engineering, Research Institute of Biomedical Engineering, School of ICT Convergence Engineering, College of Science & Technology, Konkuk University, Chungju, South Korea
| | - HYUNG-SIK KIM
- Biomedical Engineering, BK21+ Research Institute of Biomedical Engineering, Research Institute of Biomedical Engineering, School of ICT Convergence Engineering, College of Science & Technology, Konkuk University, Chungju, South Korea
| | - JI-HUN JO
- Biomedical Engineering, BK21+ Research Institute of Biomedical Engineering, Research Institute of Biomedical Engineering, School of ICT Convergence Engineering, College of Science & Technology, Konkuk University, Chungju, South Korea
| | - JI-SUN KIM
- Biomedical Engineering, BK21+ Research Institute of Biomedical Engineering, Research Institute of Biomedical Engineering, School of ICT Convergence Engineering, College of Science & Technology, Konkuk University, Chungju, South Korea
| | - JAE-HOON JUN
- Biomedical Engineering, BK21+ Research Institute of Biomedical Engineering, Research Institute of Biomedical Engineering, School of ICT Convergence Engineering, College of Science & Technology, Konkuk University, Chungju, South Korea
| | - JONG-RAK PARK
- Department of Photonic Engineering, Chosun University, Gwangju, South Korea
| | - SOON-CHEOL CHUNG
- Biomedical Engineering, BK21+ Research Institute of Biomedical Engineering, Research Institute of Biomedical Engineering, School of ICT Convergence Engineering, College of Science & Technology, Konkuk University, Chungju, South Korea
| |
Collapse
|
2
|
Development of a puff- and suction-type pressure stimulator for human tactile studies. Behav Res Methods 2017; 50:703-710. [PMID: 28411335 DOI: 10.3758/s13428-017-0895-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In this study, we developed a tactile stimulator capable of administering either puff- or suction-type stimuli. The system is composed of three parts: a control unit, an air-handling unit, and a stimulation unit. The control unit controls the type, intensity, and time of stimulation. The air-handling unit delivers the stimulation power quantitatively to the stimulation unit, as commanded by the control unit. The stimulation unit stably administers either type of pressure to the skin, without any change of the tactor. Although the design of the stimulator is simple, it allows for five levels of control of the stimulation intensity (2-6 psi) and 0.1-s steps of control of the stimulation time, as we confirmed by tests. Preliminary electroencephalographic and event-related potential (ERP) studies of our system in humans confirmed the presence of N100 and P300 waves at standard electrode position C3, which are related to perception and cognition, respectively, in the somatosensory area of the brain. In addition, different stimulation types (puff and suction) and intensities (2 and 6 psi) were reflected in different peak-to-peak amplitudes and slopes of the mean ERP signal. The system developed in this study is expected to contribute to human tactile studies by providing the ability to administer puff- or suction-type stimuli interchangeably.
Collapse
|
3
|
Decoding pressure stimulation locations on the fingers from human neural activation patterns. Neuroreport 2016; 27:1232-6. [PMID: 27631540 DOI: 10.1097/wnr.0000000000000683] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In this functional MRI study, we investigated how the human brain activity represents tactile location information evoked by pressure stimulation on fingers. Using the searchlight multivoxel pattern analysis, we looked for local activity patterns that could be decoded into one of four stimulated finger locations. The supramarginal gyrus (SMG) and the thalamus were found to contain distinct multivoxel patterns corresponding to individual stimulated locations. In contrast, the univariate general linear model analysis contrasting stimulation against resting phases for each finger identified activations mainly in the primary somatosensory cortex (S1), but not in SMG or in thalamus. Our results indicate that S1 might be involved in the detection of the presence of pressure stimuli, whereas the SMG and the thalamus might play a role in identifying which finger is stimulated. This finding may provide additional evidence for hierarchical information processing in the human somatosensory areas.
Collapse
|
4
|
Somatotopic Map and Inter- and Intra-Digit Distance in Brodmann Area 2 by Pressure Stimulation. Sci Rep 2016; 6:30243. [PMID: 27452859 PMCID: PMC4958956 DOI: 10.1038/srep30243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 07/01/2016] [Indexed: 11/09/2022] Open
Abstract
The somatotopic representation of the tactile stimulation on the finger in the brain is an essential part of understanding the human somatosensory system as well as rehabilitation and other clinical therapies. Many studies have used vibrotactile stimulations and reported finger somatotopic representations in the Brodmann area 3 (BA 3). On the contrary, few studies investigated finger somatotopic representation using pressure stimulations. Therefore, the present study aimed to find a comprehensive somatotopic representation (somatotopic map and inter- and intra-digit distance) within BA 2 of humans that could describe tactile stimulations on different joints across the fingers by applying pressure stimulation to three joints-the first (p1), second (p2), and third (p3) joints-of four fingers (index, middle, ring, and little finger). Significant differences were observed in the inter-digit distance between the first joints (p1) of the index and little fingers, and between the third joints (p3) of the index and little fingers. In addition, a significant difference was observed in the intra-digit distance between p1 and p3 of the little finger. This study suggests that a somatotopic map and inter- and intra-digit distance could be found in BA 2 in response to pressure stimulation on finger joints.
Collapse
|
5
|
Chung YG, Han SW, Kim HS, Chung SC, Park JY, Wallraven C, Kim SP. Adaptation of cortical activity to sustained pressure stimulation on the fingertip. BMC Neurosci 2015; 16:71. [PMID: 26514637 PMCID: PMC4625848 DOI: 10.1186/s12868-015-0207-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 10/02/2015] [Indexed: 11/24/2022] Open
Abstract
Background Tactile adaptation is a phenomenon of the sensory system that results in temporal desensitization after an exposure to sustained or repetitive tactile stimuli. Previous studies reported psychophysical and physiological adaptation where perceived intensity and mechanoreceptive afferent signals exponentially decreased during tactile adaptation. Along with these studies, we hypothesized that somatosensory cortical activity in the human brain also exponentially decreased during tactile adaptation. The present neuroimaging study specifically investigated temporal changes in the human cortical responses to sustained pressure stimuli mediated by slow-adapting type I afferents. Methods We applied pressure stimulation for up to 15 s to the right index fingertip in 21 healthy participants and acquired functional magnetic resonance imaging (fMRI) data using a 3T MRI system. We analyzed cortical responses in terms of the degrees of cortical activation and inter-regional connectivity during sustained pressure stimulation. Results Our results revealed that the degrees of activation in the contralateral primary and secondary somatosensory cortices exponentially decreased over time and that intra- and inter-hemispheric inter-regional functional connectivity over the regions associated with tactile perception also linearly decreased or increased over time, during pressure stimulation. Conclusion These results indicate that cortical activity dynamically adapts to sustained pressure stimulation mediated by SA-I afferents, involving changes in the degrees of activation on the cortical regions for tactile perception as well as in inter-regional functional connectivity among them. We speculate that these adaptive cortical activity may represent an efficient cortical processing of tactile information.
Collapse
Affiliation(s)
- Yoon Gi Chung
- Department of Brain and Cognitive Engineering, Korea University, Anam-5ga, Seongbuk-gu, Seoul, 136-713, Republic of Korea.
| | - Sang Woo Han
- Department of Brain and Cognitive Engineering, Korea University, Anam-5ga, Seongbuk-gu, Seoul, 136-713, Republic of Korea.
| | - Hyung-Sik Kim
- Department of Biomedical Engineering, BK21+ Research Institute of Biomedical Engineering, College of Biomedical & Health Science, Konkuk University, Chungju, 380-701, Republic of Korea.
| | - Soon-Cheol Chung
- Department of Biomedical Engineering, BK21+ Research Institute of Biomedical Engineering, College of Biomedical & Health Science, Konkuk University, Chungju, 380-701, Republic of Korea.
| | - Jang-Yeon Park
- Center for Neuroscience Imaging Research, Institute of Basic Science (IBS), Sungkyunkwan University, Suwon, 440-746, Republic of Korea. .,Department of Global Biomedical Engineering, Sungkyunkwan University, Suwon, 440-746, Republic of Korea.
| | - Christian Wallraven
- Department of Brain and Cognitive Engineering, Korea University, Anam-5ga, Seongbuk-gu, Seoul, 136-713, Republic of Korea.
| | - Sung-Phil Kim
- Department of Human and Systems Engineering, Ulsan National Institute of Science and Technology, UNIST-gil 50, Ulsan, 689-798, Republic of Korea.
| |
Collapse
|
6
|
Choi MH, Kim HS, Baek JH, Lee JC, Park SJ, Jeong UH, Gim SY, Kim SP, Lim DW, Chung SC. Differences in Activation Area Within Brodmann Area 2 Caused by Pressure Stimuli on Fingers and Joints: In Case of Male Subjects. Medicine (Baltimore) 2015; 94:e1657. [PMID: 26402840 PMCID: PMC4635780 DOI: 10.1097/md.0000000000001657] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
In this study, a constant pressure stimulus was applied on the 3 joints (first [p1], second [p2], and third [p3] joints) of 4 fingers (index, middle, ring, and little fingers), and the activation areas within Brodmann area 2 (BA 2) were compared for these different fingers and joints by using functional magnetic resonance imaging. Eight healthy male college students (25.4 ± 1.32 years) participated in the study. Each session was composed of 3 blocks, and each block was composed of a Control phase (30 seconds) and a Pressure phase (30 seconds). No pressure stimulus was applied in the Control phase, during which the subjects would simply lay comfortably with their eyes closed. In the Pressure phase, a pressure stimulus was applied onto one of the joints of the selected finger. For each finger and joint, BA 2 areas activated by the pressure stimulus were extracted by the region of interest method. There was a significant difference in the activation areas for the different fingers (P = .042) as well as for the different joints (P = .050). The activation area decreased in the order of the little, index, and middle fingers, as well as in the order of p1, p3, and p2.
Collapse
Affiliation(s)
- Mi-Hyun Choi
- From the Department of Biomedical Engineering (M-HC, H-SK, J-HB, J-CL, S-JP, U-HJ, S-YG, S-CC), Research Institute of Biomedical Engineering, College of Biomedical & Health Science, Konkuk University, Chungju; Department of Human and Systems Engineering (S-PK), Ulsan National Institute of Science and Technology, Ulsan; and Department of Information and Communication Engineering (D-WL), Dongguk University, Seoul, South Korea
| | | | | | | | | | | | | | | | | | | |
Collapse
|
7
|
Kim HS, Kim JS, Jung GI, Jun JH, Park JR, Kim SP, Choi S, Park SJ, Choi MH, Chung SC. Evaluation of the possibility and response characteristics of laser-induced tactile sensation. Neurosci Lett 2015; 602:68-72. [PMID: 26145316 DOI: 10.1016/j.neulet.2015.06.053] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Revised: 06/13/2015] [Accepted: 06/29/2015] [Indexed: 10/23/2022]
Abstract
In this study, we examined the possibility and perceptual response characteristics of tactile sense induced by laser stimulation to the finger with different laser energy densities through human response experiments. 15 healthy adult males and 4 healthy adult females with an age of 22.6±2.2 years were tested. A frequency-doubled Q-switched laser was used with a wavelength of 532 nm and a 5 ns pulse width. The experimental trial spanned a total of 30 s and included a rest phase (19 s), a stimulation phase (7 s), and a response phase (4 s). During the rest phase, subjects kept their fingers comfortable. During the stimulation phase, one of three types of laser energy density (13.5, 16.6, 19.8 mJ/cm(2)) or a sham stimulation was used to irradiate the distal phalanx on the right index finger. During the response phase, the cognitive response to the laser stimulation was recorded by a PC by pressing the response button. The confusion matrix was configured to evaluate the possibility that the tactile sense was caused by the laser. In addition, changes in the response characteristics were observed according to three types of laser energy densities. From the analysis of the confusion matrix, the accuracy and sensitivity were not high. In contrast, precision and specificity were found to be high. Furthermore, there was a strong positive correlation between the laser irradiation and tactile perception, indicating that tactile sense can be induced using a laser in a mid-air manner. In addition, it was found that as the laser energy density increased, the tactile perception possibility also increased.
Collapse
Affiliation(s)
- Hyung-Sik Kim
- Department of Biomedical Engineering, BK21+ Research Institute of Biomedical Engineering, College of Biomedical & Health Science, Konkuk University, Chungju, Chungbuk 380-701, South Korea
| | - Ji-Sun Kim
- Department of Biomedical Engineering, BK21+ Research Institute of Biomedical Engineering, College of Biomedical & Health Science, Konkuk University, Chungju, Chungbuk 380-701, South Korea
| | - Gu-In Jung
- Department of Biomedical Engineering, BK21+ Research Institute of Biomedical Engineering, College of Biomedical & Health Science, Konkuk University, Chungju, Chungbuk 380-701, South Korea
| | - Jae-Hoon Jun
- Department of Biomedical Engineering, BK21+ Research Institute of Biomedical Engineering, College of Biomedical & Health Science, Konkuk University, Chungju, Chungbuk 380-701, South Korea
| | - Jong-Rak Park
- Department of Photonic Engineering, Chosun University, Gwangju 501-759, South Korea
| | - Sung-Phil Kim
- Department of Human and Systems Engineering, Ulsan National Institute of Science and Technology, Ulsan 689-798, South Korea
| | - Seungmoon Choi
- Department of Computer Science and Engineering, Pohang University of Science and Technology, Pohang, Gyeongbuk 790-784, South Korea
| | - Sung-Jun Park
- Department of Biomedical Engineering, BK21+ Research Institute of Biomedical Engineering, College of Biomedical & Health Science, Konkuk University, Chungju, Chungbuk 380-701, South Korea
| | - Mi-Hyun Choi
- Department of Biomedical Engineering, BK21+ Research Institute of Biomedical Engineering, College of Biomedical & Health Science, Konkuk University, Chungju, Chungbuk 380-701, South Korea
| | - Soon-Cheol Chung
- Department of Biomedical Engineering, BK21+ Research Institute of Biomedical Engineering, College of Biomedical & Health Science, Konkuk University, Chungju, Chungbuk 380-701, South Korea.
| |
Collapse
|
8
|
Chung YG, Han SW, Kim HS, Chung SC, Park JY, Wallraven C, Kim SP. Intra- and inter-hemispheric effective connectivity in the human somatosensory cortex during pressure stimulation. BMC Neurosci 2014; 15:43. [PMID: 24649878 PMCID: PMC3994419 DOI: 10.1186/1471-2202-15-43] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 03/13/2014] [Indexed: 01/08/2023] Open
Abstract
Background Slow-adapting type I (SA-I) afferents deliver sensory signals to the somatosensory cortex during low-frequency (or static) mechanical stimulation. It has been reported that the somatosensory projection from SA-I afferents is effective and reliable for object grasping and manipulation. Despite a large number of neuroimaging studies on cortical activation responding to tactile stimuli mediated by SA-I afferents, how sensory information of such tactile stimuli flows over the somatosensory cortex remains poorly understood. In this study, we investigated tactile information processing of pressure stimuli between the primary (SI) and secondary (SII) somatosensory cortices by measuring effective connectivity using dynamic causal modeling (DCM). We applied pressure stimuli for 3 s to the right index fingertip of healthy participants and acquired functional magnetic resonance imaging (fMRI) data using a 3T MRI system. Results DCM analysis revealed intra-hemispheric effective connectivity between the contralateral SI (cSI) and SII (cSII) characterized by both parallel (signal inputs to both cSI and cSII) and serial (signal transmission from cSI to cSII) pathways during pressure stimulation. DCM analysis also revealed inter-hemispheric effective connectivity among cSI, cSII, and the ipsilateral SII (iSII) characterized by serial (from cSI to cSII) and SII-level (from cSII to iSII) pathways during pressure stimulation. Conclusions Our results support a hierarchical somatosensory network that underlies processing of low-frequency tactile information. The network consists of parallel inputs to both cSI and cSII (intra-hemispheric), followed by serial pathways from cSI to cSII (intra-hemispheric) and from cSII to iSII (inter-hemispheric). Importantly, our results suggest that both serial and parallel processing take place in tactile information processing of static mechanical stimuli as well as highlighting the contribution of callosal transfer to bilateral neuronal interactions in SII.
Collapse
Affiliation(s)
| | | | | | | | | | - Christian Wallraven
- Department of Brain and Cognitive Engineering, Korea University, Seoul, Republic of Korea.
| | | |
Collapse
|