Intrinsic neural streams for perception and action : cortical orchestra conducted by purpose and function

윤석윤 서울대학교 대학원 2020 국내박사

Tactile and proprioceptive perceptions are crucial for our daily life as well as survival. At the peripheral level, the transduction mechanisms and characteristics of mechanoreceptive afferents containing information required for these functions, have been well identified. However, our knowledge about the cortical processing mechanism for them in human is limited. The present series of studies addressed the macroscopic neural mechanism for perceptual processing of tactile and proprioceptive perception in human cortex. In the first study, I investigated the macroscopic neural characteristics for various vibrotactile and texture stimuli including artificial and naturalistic ones in human primary and secondary somatosensory cortices (S1 and S2, respectively) using electrocorticography (ECoG). I found robust tactile frequency-specific high-gamma (HG, 50–140 Hz) activities in both S1 and S2 with different temporal dynamics depending on the stimulus frequency. Furthermore, similar HG patterns of S1 and S2 were found in naturalistic stimulus conditions such as coarse/fine textures. These results suggest that human vibrotactile sensation involves macroscopic multi-regional hierarchical processing in the somatosensory system, even during the simplified stimulation. In the second study, I tested whether the movement-related HG activities in parietal region mainly represent somatosensory feedback such as proprioception from periphery or primarily indicate cortico-cortical neural processing for movement preparation and control. I found that sensorimotor HG activities are more dominant in S1 than in M1 during voluntary movement. Furthermore, the results showed that movement-related HG activities in S1 mainly represent proprioceptive and tactile feedback from periphery. Given the results of previous two studies, the final study aimed to identify the large-scale cortical networks for perceptual processing in human. To do this, I combined direct cortical stimulation (DCS) data for eliciting somatosensation and ECoG HG band (50 to 150 Hz) mapping data during tactile stimulation and movement tasks, from 51 (for DCS mapping) and 46 patients (for HG mapping) with intractable epilepsy. The results showed that somatosensory perceptual processing involves neural activation of widespread somatosensory-related network in the cortex. In addition, the spatial distributions of DCS and HG functional maps showed considerable similarity in spatial distribution between high-gamma and DCS functional maps. Interestingly, the DCS-HG combined maps showed distinct spatial distributions depending on the somatosensory functions, and each area was sequentially activated with distinct temporal dynamics. These results suggest that macroscopic neural processing for somatosensation has distinct hierarchical networks depending on the perceptual functions. In addition, the results of the present study provide evidence for the “perception and action” related neural streams of somatosensory system. Throughout this series of studies, I suggest that macroscopic somatosensory network and structures of our brain are intrinsically organized by perceptual function and its purpose, not by somatosensory modality or submodality itself. Just as there is a purpose for human behavior, so is our brain. 촉각과 자기수용감각은 우리의 생존 및 일상생활에 절대적인 영향을 미치는 중요한 감각 기능이다. 말초신경계에서 이 두 가지 기능들에 필요한 정보를 수집하고 전달하는 기계적 수용기 및 그 구심성 신경들에 대한 신호 전달 메커니즘 및 그 특징들은 상대적으로 잘 알려져 있는 편이다. 그러나, 촉각과 자기수용감각을 형성하기 위한 인간 뇌의 피질에서의 정보 처리 메커니즘에 대하여 우리가 현재 알고 있는 바는 극히 일부분이다. 이 논문에서 제시하는 일련의 연구들은 인간 뇌 피질 단계에서 촉각과 자기수용감각의 지각적 처리과정에 대한 거시적 신경계 정보처리 메커니즘을 다룬다. 첫 번째 연구에서는 뇌피질뇌파를 이용하여 인간 일차 및 이차 체성감각 피질에서 인공적인 자극과 일상생활에서 접할 수 있는 자극을 포함하는 다양한 진동촉감각 및 질감 자극에 대한 거시적 신경계 정보처리 특성을 밝혔다. 이 연구에서는 일차 및 이차 체성감각 피질의 촉감각 주파수 특이적인 하이-감마 영역 신경활동이 자극 주파수에 따라 각각 상이한 시간적 다이나믹스를 가지고 변화하는 것을 확인하였다. 또한, 이러한 하이-감마 활동은 성긴 질감과 미세한 입자감을 가진 자연스러운 질감 자극에 대해서도 진동촉감각의 경우와 유사한 패턴을 보였다. 이러한 결과들은 인간의 진동촉감각이 매우 단순한 형태에 자극일지라도 대뇌 체성감각 시스템에 있어 거시적인 다중 영역에서의 계층적 정보처리를 동반한다는 점을 시사한다. 두 번째 연구에서는 인간의 움직임과 관련된 두정엽 영역에서의 하이-감마 뇌활성이 자기수용감각과 같은 말초신경계로부터의 체성감각 피드백을 주로 반영하는지, 아니면 움직임 준비 및 제어를 위한 피질 간 신경 프로세스에 대한 활동을 반영하는지를 조사하였다. 연구 결과, 자발적 운동 중 대뇌 운동감각령에서의 하이-감마 활동은 일차 체성감각피질이 일차 운동피질보다 더 지배적인 것으로 나타났다. 또한 이 연구에서는, 움직임과 관련된 일차 체성감각피질에서의 하이-감마 뇌활동은 말초신경계로부터의 자기수용감각과 촉각에 대한 신경계 정보처리를 주로 반영하는 것을 밝혔다. 이러한 연구들을 바탕으로, 마지막 연구에서는 인간 대뇌에서의 체성감각 지각 프로세스에 대한 거시적 피질 간 네트워크를 규명하고자 하였다. 이를 위해, 51명의 뇌전증 환자에게서 체성감각을 유발했던 뇌피질전기자극 데이터와 46명의 환자에게서 촉감각 자극 및 운동 수행 중에 측정한 뇌피질뇌파 하이-감마 매핑 데이터를 종합적으로 분석하였다. 그 결과, 체성감각 지각 프로세스는 대뇌에서 넓은 영역에 걸쳐 분포하는 체성감각 관련 네트워크의 신경 활성을 수반한다는 것을 알아냈다. 또한, 뇌피질전기자극을 통한 대뇌 지도와 하이-감마 매핑을 통한 대뇌 지도는 서로 상당한 유사성을 보였다. 흥미롭게도, 뇌피질전기자극과 하이-감마 활동을 종합한 뇌지도들로부터 체성감각 관련 뇌 영역의 공간적 분포가 체성감각 기능에 따라 서로 달랐고, 그에 해당하는 각 영역들은 서로 뚜렷하게 다른 시간적 다이나믹스를 가지고 순차적으로 활성화되었다. 이러한 결과들은 체성감각에 대한 거시적 신경계 프로세스가 그 지각적 기능에 따라 뚜렷이 다른 계층적 네트워크를 가진다는 점을 시사한다. 더 나아가, 본 연구에서의 결과들은 체성감각 시스템의 지각-행동 관련 신경활동 흐름에 관한 이론적인 가설에 대하여 설득력 있는 증거를 제시하고 있다.

Ultra high-field mouse fMRI & somatosensory networks

Jung, Wonbeom Sungkyunkwan university 2020 국내박사

Animal functional magnetic resonance imaging (fMRI) is an excellent tool to investigate underlying hemodynamic response contributing to fMRI signal mechanisms and to probe the brain function. In particular, mouse is major animal model of choice for neuroscience research due to the availability of a large genetic toolbox. This allows mouse fMRI to understand the role of specific genes linked to behavior and disease and to study the cell-type specific neural circuit in the whole brain. However, the utility of mouse fMRI is closely dependent on its ability to detect neural active-functional networks with high fidelity. This work begins with investigation of field strength-dependent fMRI sensitivity by comparing somatosensory-evoked blood oxygenation-level dependent (BOLD) signals obtained at 9.4 T and 15.2 T, in the mouse brain. The functional detectability was improved by ≥ 2 times with increasing magnetic field strength due to higher temporal signal to noise ratio (tSNR) and larger BOLD changes. In addition, the improvement in functional detectability at cortical and thalamic areas was able to demonstrate functional somatosensory networks, which is consistent with neural tracing connectivity map. The somatosensory networks are organized by feed-forward and feed-back projections during functional processing. Therefore, the second part of this work focuses on the functional dissection of somatosensory networks using mouse fMRI combined with optogenetics at 15.2 T. For somatosensory processing, thalamic nuclei were functionally connected with primary somatosensory cortex (S1FL). The ventral posterolateral nucleus (VPL) relayed sensory input to S1FL, while the posterior complex of thalamus (PO) activity was driven by the S1FL projection. The stimulus-evoked signal relayed to S1FL via thalamo-cortical projection was amplified by the recurrent excitatory S1FL networks. The responses in primary motor cortex (M1) and secondary somatosensory cortex (S2) were mainly due to S1FL projections. These findings raised the question whether fMRI signal can detect the sequential order of functional processing in somatosensory networks. The final part of this work explores the temporal dynamics in somatosensory networks with high-temporal-resolution mouse fMRI. The sequential order of BOLD signal (VPL -> S1FL -> M1, PO and S2) concurred with that of the neural pathways, but inter-regional neural processing in the sub-millisecond scale was translated into a few hundred millisecond BOLD signal difference. Since BOLD dynamic response results from the convolution of underlying neural activity with hemodynamic response, further vascular physiology studies are necessary to verify whether the differences in the sequential fMRI onset arose from the neural activity sequence or vascular response. Consequently, ultrahigh field mouse fMRI provides the unique window in understanding brain functional networks. Combined with optogenetics and chemogenetics, this can open a new research avenue to reveal new regions of interest in unknown functional networks and to allow better brain-wide functional analysis.

Age-related changes of single-limb standing balance in children with and without deafness

안미희 Graduate School, Yonsei University 2009 국내석사

The purposes of the present study were to elucidate the age-related changes in single-limb standing balance and sensory compensation for maintaining single-limb standing in profoundly deaf (PD) children, and to compare them with age-matched normal-hearing (NH) children. This study involved 57 PD children, aged 4?14 years and 57 age-matched NH children. Each group was subdivided into the following age groups: 4-6 years, 7-9 years, and 12-14 years. Postural stability was assessed using a Single-limb standing test under four different sensory conditions: standing on a firm surface with eyes open (condition 1), standing on a firm surface with eyes closed and covered (condition 2), standing on a foam surface with eyes open (condition 3), and standing on a foam surface with eyes closed and covered (condition 4). The age-related changes in single-limb standing balance of the PD children were notably affected by sensory conditions, in contrast with those of the NH children, which were not influenced by sensory conditions. In conditions 1 and 3, where visual information was enabled, the mean time of maintaining single-limb standing for the PD children significantly increased with age, and even reached levels similar to those of the NH children. However, in condition 2, where visual input was removed, the deficit of single-limb standing balance in the PD children persisted. Condition 4 revealed no significant age-related changes in the PD children. These results suggest that the postural stability of PD children improves as a result of adaptive sensory compensation, both visual and somatosensory. In addition, it appears that postural control is more highly dependent upon visual input than on somatosensory input. 본 연구는 청각장애아동과 건청아동의 연령 증가에 따른 균형 발달과 감각 보상 작용에 대해 알아보고 두 집단간 차이를 비교하기 위해 시행되었다. 4-14세 청각장애아동 57명과 동일 연령대의 건청아동 57명이 본 연구에 참여하였고 연령에 따라 세 집단(4-6세, 7-9세, 12-14세)으로 나뉘었다. 네 가지 감각조건에서 외발서기 평가를 실시하여 아동의 균형능력을 측정하였으며, 감각조건은 다음과 같다: 단단한 지지면에서 눈을 뜬 상태(조건 1), 단단한 지지면에서 눈을 감고 안대를 착용한 상태(조건 2), 불안정한 지지면에서 눈을 뜬 상태(조건 3), 불안정한 지지면에서 눈을 감고 안대를 착용한 상태(조건 4). 연구 결과, 건청아동의 경우, 검사 조건이 균형 발달에 영향을 미치지 않는 반면, 청각장애 아동의 경우, 검사 조건이 연령에 따른 균형 능력의 변화에 영향을 미치는 것을 알 수 있었다. 검사 조건 별로 살펴보면, 시각정보를 이용할 수 있는 조건(조건 1, 조건 3)에서 청각장애 아동의 균형 능력은 연령이 증가함에 따라 유의미하게 향상되었으며 조건 3의 경우, 건청아동과 비슷한 수준으로 발달하였다. 반면, 시각정보 입력이 차단된 상황에서는 모든 연령 집단에서 건청아동과 비교하여 유의미하게 낮은 균형 능력을 보였고(조건 2), 연령 증가에 따른 균형 능력의 변화가 나타나지 않았다(조건 4). 이러한 결과들은 청각장애 아동의 균형 발달이 시각, 고유수용성 감각을 이용한 감각 보상 작용에 의해 이루어짐을 보여주는 것이다. 또한, 조건 2와 조건 3의 결과를 비교해 볼 때, 고유수용성 감각 보다 시각을 이용한 감각 보상에 더 의존하여 균형을 발달시키고 있음을 알 수 있다. 지속적으로 시각에 의존하여 균형을 유지할 경우, 시각정보가 부정확하거나 시각정보를 이용하기 어려운 상황에서는 균형을 유지하기 어려울 것이다. 그러므로 청각장애 아동이 적절한 균형 발달을 이루기 위해서 고유수용성 감각 기능의 강화와 감각통합 훈련이 필요할 것으로 생각된다.

Development of ECoG electrode array integrated with wireless recording system

Daun Hong DGIST 2021 국내석사

Nowadays, technological advancement of micro-electro-mechanical systems (MEMS) has enabled neural electrode for brain-machine interfaces (BMI) to be sophisticated. The size of the electrode pad has become smaller and the number of recording channels has increased that it can detect high-resolution signals in a wide-scale neuronal area simultaneously. On the other hand, recent wireless recording systems used for getting neural signal still have low data throughput that it can be used at restricted applications to record just small amounts of neuronal data, which drops the merits of the electrode. These wireless recording systems must overcome the disadvantage to achieve better experimental environment and fully implantable applications for freely moving living things. This study suggests integration of ECoG electrode array and wireless recording system with high-throughput. The ECoG electrode array is fabricated with soft polymer of polydimethysiloxane (PDMS) and gold electrode pads. It has 32 recording channels which has a diameter of 400 μm, and 1 reference channel connected by four pads in line which has diameter of 1 mm each. The wireless recording system is assembled consisting of an electrophysiology interface chip, a microcontroller of ARM® Cortex®-M7 processor and a wireless transceiver of IEEE 802.11 b/g/n Wi-Fi® protocol. The recording system has a compact size of 18 x 15 x 10 mm3 and a light weight of 2.1 g. The integrated system can handle up to 32 recording channels with a sampling rate of 30 kSamples/s per channel simultaneously, which is equivalent to the throughput of 15.36 Mbps. To evaluate and verify the developed system, several tests of the electrical characteristics, system performance, and in-vivo recording experiment targeted to rabbit were conducted. The experiment contains procedures to stimulate surface of forepaw and measure the event-related potentials (ERPs), so that somatosensory-evoked potentials (SEPs) is obtained. A tactile stimulation system is developed for the experiment to apply uniformed mechanical tactile stimulus. As a result, the electrode-integrated wireless recording system could measure and record the neuronal data successfully, and the data was analyzed at the time and frequency domain. The signal’s shape and tendency according to recording channels was discussed at the end. 오늘날 미세 전자-기계 시스템(MEMS)의 기술적인 향상으로 뇌-기계 인터페이스(BMI)에 사용되는 신경 전극은 보다 정교해지게 되었다. 전극 패드의 크기는 보다 소형화되고 채널의 개수는 많아지면서 전극은 넓은 신경영역에서 높은 분해능의 신호를 동시에 검출할 수 있게 된 것이다. 반면에, 신경 신호를 얻기 위해 사용되는 최근의 무선 기록 시스템들은 여전히 낮은 데이터 처리량을 가지고 있어서 단지 적은 양의 신경 데이터를 기록하는 어플리케이션에 국한되어 사용될 수 있는데, 이것은 신경 전극이 가지는 이점을 감소시킨다. 이러한 무선 기록 시스템은 향상된 실험환경을 달성하고 자유롭게 움직이는 생명체에 대하여 완전히 이식할 수 있는 어플리케이션을 위해서 반드시 그 단점이 극복되어야 하는 실정이다. 본 논문은 피질뇌파검사(ECoG) 전극 배열과 높은 처리량을 가지는 무선 기록 시스템과의 통합을 제안한다. ECoG 전극 배열은 PDMS 기반의 유연한 폴리머와 금 전극패드로 제작되었다. 이 전극은 400 μm 직경을 갖는 32개의 기록 채널과 각각 1 mm 직경을 갖는 4개의 패드가 하나로 연결된 1 개의 참조 채널을 갖는다. 무선 기록 시스템은 전기생리학 인터페이스 칩, ARM® Cortex®-M7 프로세서를 갖는 마이크로컨트롤러, 그리고 IEEE 802.11 b/g/n Wi-Fi® 프로토콜을 갖는 무선 송수신기로 구성되어 제작되었다. 이 기록 시스템은 18 x 15 x 10 mm3의 소형 크기와 2.1 g의 가벼운 무게로 제작되었다. 통합된 시스템은 최대 32 개의 기록 채널을 채널당 30 kSamples/s 로 동시에 측정할 수 있으며 이것은 15.36 Mbps 처리량에 대응된다. 개발된 시스템을 평가하고 입증하기 위하여, 전기적 특성 테스트, 시스템 성능 테스트, 토끼를 대상으로 신경 기록을 위한 생채 내 실험이 시행되었다. 이 실험은 토끼의 앞발 표면을 자극하여 사건유발전위(ERPs)를 측정하는 과정을 포함하며, 그 결과 체성감각유발전위(SEPs)가 얻어진다. 이 실험에서 주기적인 기계적 촉각 자극을 가할 수 있도록 하는 촉각 자극 시스템이 개발되었다. 실험 결과 전극이 통합된 무선 기록 시스템은 신경 데이터를 성공적으로 측정하고 기록할 수 있었으며, 그 데이터는 시간과 주파수 영역에 대하여 분석이 이루어졌다. 그리고 신호의 형상과 측정 채널에 따른 신호의 경향성이 끝에 논의되었다.

체성감각자극에 따른 자세균형 제어의 연구

유미 전북대학교 대학원 2009 국내박사

Postural control is the ability to maintain equilibrium of body or human body within spatial domain. Normal posture equilibrium control is defined as the ability to maintain the center of gravity of body in the midst of minimum swaying of posture, and is accomplished through mutual equilibrium of sensory information of visual, vestibular and somatosensory system and movements. Among these, the somatosensory system is divided largely into tactile senses and proprioception, and plays essential role in posture equilibrium control and development. Therefore, research on posture equilibrium control in accordance with somatosensory stimulus input under static and dynamic posture was pursued in this Study. Stimulus system that can individually input information into tactile sensory and proprioception system, and stimulus system that can detect such during walking and apply such input into the somatosensory system were developed. Forceplate that can analyze the kinetic data as posture equilibrium control response measurement system in accordance with the somatosensory stimulus, 3D motion analysis system for unstable support and kinematic data, evaluation of pressure on foot and electromyograph measurement system were used. Under static posture, effect of type of receptor to which somatosensory stimulation was applied, and posture equilibrium control in accordance with the area of application of stimulation and stimulus frequency was evaluated. In the first experiment, the effect of posture equilibrium control was analyzed after having applied tactile stimulus of smoatosensory system to the sole of the food and ankle joint muscles, and somatosensory stimulus that stimulates proprioception while in standing up posture on stable support plate and unstable support plate. As the result, rate of reduction in movement of center of gravity of the body was greater when somatosensory stimulus was applied while on unstable support plate than while on sable support plate. This is due to the greater increase in posture stability effect through greater activation of centripetal sensory flow induced by the somatosensory stimulation while on unstable support plate. In the second experiment, directional characteristics of posture equilibrium control on somatosensory stimulation when stimulus was applied individually to neck joint muscle and ankle joint muscle by dividing the area of application of stimulus into upper and lower body was evaluated. As the result, it was confirmed that center of gravity of the body moves in the same direction of the location of the somatosensory stimulus applied to ankle joint muscle, and in the opposite direction of somatosensory stimulus applied to the neck joint muscle. In the third experiment, response of the posture equilibrium was measured by varying stimulus frequency (20, 60 and 100Hz) and area of stimulation area (front and rear regions of sole of the foot) by suing vertical type somatosensory stimulation, and the following results were obtained. As the frequency of vibration stimulus increased, center of gravity of body, joint angle and level of activation of muscle either increased or decreased, and the center of gravity of body moved in the direction of the location of the vibration stimulation due to the effect of somatosensory stimulation, and the angle of each joint also maintain posture stability in accordance with the altered center of gravity of the body. Accordingly, stimulation of particular location of vibration stimulation is interpreted by the central nervous system through changes exhibited in various somatosensory receptors including tactile receptor and induces response of posture equilibrium control that displays particular directionality through feed back. When problem in posture equilibrium control related to the support surface as the result of static stimulation occurs, posture equilibrium control effect related to the effect of inputting of somatosensory stimulation, particular directionality related to the area of application of stimulation and frequency of somatosensory stimulus were obtained. The effectiveness of somatosensory system under dynamic posture during abnormal walking due to obstacles by suing stimulation system that can detect such and apply somatosensory stimulation during abnormal walking was analyzed by applying the results of the static stimulation with youth and aged groups as the subjects. In the fourth experiment, results of application and non-application of somatosensory stimulation to the lower limb (anterior tibial tendon and Achilles tendon) under upright posture in the task of crossing over obstacles whose lengths are 5, 10 and 15% of the height of subjects of the experiment were compared with youth as subjects. The results confirmed that stimulation of anterior tibial tendon and Achilles tendon while crossing over obstacles stabilizes posture more so than when somatosensory stimulus is not applied by stably changing the center of the gravity of body in antero-posterior direction and medio-lateral direction. In the fifth experiment, application and non-application of somatosensory stimulus to the lower limb (anterior tibial tendon and Achilles tendon) under each state in the task similar to that of the fourth experiment but with aged personas as subjects were compared through pressure on foot and speed of movement of center of gravity of the body. As the result, the pressure on foot displayed even distribution when somatosensory stimulus was applied while crossing over the obstacles and the speed of movement of center of gravity of the body also decreased, thereby achieving stabilization of the posture in the crossing over of obstacles. That is, somatosensory stimulus applied to the lower limb was effective in stabilizing the posture by providing immediate feedback. The results of this Study, which is a research on posture equilibrium control through somatosensory stimulation, obtained the conclusion that somatosensory stimulation is effective in obtaining particular posture equilibrium control response related to sensory receptor, location of stimulation and frequency in relations to the somatosensory information under static state, and is effective in detecting abnormal walking and stabilizing posture during abnormal walking under dynamic state. If somatosensory stimulation is utilized on patients or aged persons for whom the muscular strength of lower limb is weak or has deviated posture is used in the future, it is expected to make contribution not only towards posture control on stabilization of posture but also in preventing injuries from falling. 자세균형 제어는 공간 영역 내에서 신체의 균형(balance) 혹은 인체의 평형(equilibrium)을 유지하는 능력이다. 정상적인 자세균형 제어는 최소한의 자세 흔들림 속에서 신체의 무게 중심을 유지하는 능력으로 정의 되며, 시각, 전정감각, 체성감각의 감각정보와 운동의 상호 균형 속에서 이루어진다. 이 중 체성감각은 크게 촉각과 고유수용감각으로 나누어지며 자세균형 제어와 발달에 필수적인 역할을 한다. 따라서 본 논문에서는 정적 자세와 동적자세에서 체성감각 입력에 따른 자세균형 제어에 관한 연구를 실시하였다. 촉각, 고유수용감각에 각기 개별적으로 입력할 수 있는 자극 시스템과 이상 보행 시 이를 검출하여 체성감각을 인가할 수 있는 자극 시스템을 개발하였고, 체성감각에 따른 자세균형 제어 응답 측정 시스템으로 kinetic 데이터를 분석할 수 있는 힘판(forceplate)과 불안정판(unstable support), kinematic 데이터를 위한 3차원 동작 분석 시스템(3D motion analysis system), 족부 압력 평가와 근전도(electromygraph, EMG) 측정 시스템을 사용하였다. 정적 자세에서는 체성감각 자극이 인가된 수용기의 종류, 자극 인가 부위와 자극 주파수에 따른 자세균형 제어의 영향을 평가하였다. 첫 번째 실험은 발바닥과 발목 관절 근육에 체성감각계의 촉각자극과 고유수용감각을 자극시키는 체성감각 자극을 안정판과 불안정판 지지대 위의 기립상태에서 인가한 후 자세균형 제어 영향을 분석하였다. 그 결과, 안정판 지지대에서보다 불안정판 지지대에서 체성감각 자극을 인가하였을 때, 체중심 이동의 감소율이 더 크게 나타났고, 이는 체성감각 자극으로 유도된 구심성 신경 흐름이 불안정한 지지면 상태에서 더 활성화되어 자세 안정성의 효과가 더 크게 증가하였기 때문이다. 두 번째 실험은 자극 인가 부위를 상체와 하체로 나뉘어 각각 목근육과 족관절 근육에 개별적으로 인가하였을 때, 체성감각 자극에 관한 자세균형 제어의 방향 특성을 평가하였다. 그 결과, 족관절 근육에 인가된 체성감각 자극의 위치와 동일한 방향으로 체중심이 이동되며, 목관절 근육에 체성감각이 인가되었을 때는 자극과 반대의 방향으로 체중심이 이동되는 것을 확인하였다. 세 번째 실험은 수직형 체성감각 자극을 이용하여 자극 주파수(20, 60, 100Hz)와 자극 부위(발바닥 앞, 뒤 영역)를 달리하여 자세균형 응답에 대하여 아래와 같은 결과를 얻었다. 진동자극 주파수가 증가 할수록 체중심, 관절각도와 근활성도는 증가하거나 감소하고 발바닥의 위치에 따른 체성감각 자극의 영향으로 체중심은 진동자극 위치와 반대로 이동하였으며, 각 관절의 각도 역시 변화된 체중심에 맞추어 자세안정을 유지한다. 이로써 진동자극의 특정 위치 자극은 촉각 수용기를 비롯한 여러 체성감각 수용기에서 나타난 변화에 의해 중추신경계에서 해석되어 피드백을 통해 특정 방향성을 띠는 자세균형 제어의 반응을 유발한다. 정적 자극의 결과로 지지면과 관련한 자세균형 제어의 문제점이 발생했을 때 체성감각 자극 입력의 효과, 자극의 인가 부위와 관련한 특정 방향성, 체성감각 자극 주파수와 관련한 자세균형 제어 영향을 얻었다. 정적 자극의 결과를 응용하여, 이상보행 시 이를 검출하고 체성감각을 인가할 수 있는 자극 시스템을 사용하여 장애물 보행으로 인한 이상 보행 시 청년층과 고령자층을 대상으로 동적 자세에서 체성감각의 효용성을 분석하였다. 네 번째 실험은 청년층을 대상으로 피험자 신장의 5, 10, 15%의 장애물 건너기 과제에서 입각기 상태의 하지(전경골건, 아킬레스건)에 체성감각을 인가하였을 때와 인가하지 않았을 때를 비교하였다. 그 결과 장애물을 건너는 동안 전경골건 및 아킬레스건의 체성감각 자극은 전-후 방향 및 좌-우 방향을 안정적으로 체중심을 변화시킴으로써 체성감각이 주어지지 않았을 때보다 자세를 안정화시킴을 확인하였다. 다섯 번째 실험은 고령자층을 대상으로 네 번째 실험과 동일한 과제에서 각기 상태의 하지(전경골건, 아킬레스건)에체성감각을 인가하였을 때와 인가하지 않았을 때를 족부압력과 체중심 이동 속도를 통해 비교하였다. 그 결과 장애물을 건너는 동안 체성감각이 인가되었을 때 족부압력은 고른 분포를 보였으며, 체중심 이동속도 역시 낮아져서 장애물 건너기 과제에서 자세를 안정화 시키는 역할을 하는 것으로 분석되었다. 즉, 하지에 입력된 체성감각은 즉각적인 피드백을 제공하여 자세를 안정화 시키는데 효과가 있었다. 이번 연구 결과는 체성감각에 따른 자세균형 제어에 관한 연구이며, 정적 상태에서 체성감각 정보와 관련하여 감각수용기, 자극 위치, 주파수와 관련한 특정 자세균형 제어 응답을 얻고, 동적 상태에서는 이상보행에 대해 검출하고 이상보행 시 자세를 안정화 시키는데 효과가 있다는 결론을 얻었다. 향후 하지 근력이 약하거나 자세가 편향되어 있는 환자나 노약자를 대상으로 체성감각자극을 활용한다면, 자세 안정화에 관한 자세 제어뿐만 아니라 낙상을 예방하는데 기여할 수 있을 것으로 예상된다.

침의 복합적 구심성 입력에 의한 뇌의 상호작용 : 다수의 침 특이적 중추신경 기전 제시

정창진 경희대학교 대학원 2023 국내박사

Acupuncture is a therapeutic technique that modulates the underlying mechanisms of the body and induces clinical outcomes by inserting and stimulating needles at specific points on the skin. Needle stimulation is applied at specific points on the skin, but its effects are not confined to the stimulated region of the body. Clinical studies have demonstrated the efficacy of acupuncture on various systems of the body, suggesting that acupuncture can be associated with signaling mechanisms in the body, including the central nervous system (CNS). Studies on the mechanism of action of acupuncture in the CNS have been published with technological advances in functional magnetic resonance imaging (fMRI) over the past 20 years. Early studies focused on local brain regions induced by acupuncture stimuli to investigate acupuncture-specific brain regions. Furthermore, studies have attempted to identify acupuncture-induced response patterns in the brain, which may be associated with clinical outcomes. Currently, randomized controlled trial have been performed with fMRI studies for acupuncture to find acupuncture-induced brain alterations and the associating clinical outcomes. These studies investigated which brain regions contribute to acupuncture-induced clinical outcomes; however, they revealed a certain limitation in specifying dissociable linkages of various acupuncture afference types to outcome-related brain regions, which might be acupuncture-specific mechanisms in the nervous system. Acupuncture is a compound stimulus that induces various somatosensory afferences (i.e., spinothalamic, spinorecticular, and spinomesencephalic tracts) and visual afferences for contextual manipulation of the treatment. Existing neuroscience findings have consolidated the cognitive modulation of somatosensory processes in the brain. The somatosensory area in the cortex and primary sensory thalamus in the ascending somatosensory pathway show activity changes by cognitive/affective processes. Similarly, somatosensory afferents and the contextual manipulation of acupuncture can interact with the brain. Furthermore, a specific interaction with the compound stimulus may be linked to outcome-related brain regions. Thus, this dissertation investigated the underlying mechanisms of the interactions between various afferent signals of an acupuncture-specific compound stimulus in the brain using fMRI. The compound stimulus of acupuncture was divided into two components: somatosensory afferent and contextual manipulation. Experimental paradigms to dissociate these components were performed for healthy participants. Study-1 tried to investigate brain responses focusing on the somatosensory processes of acupuncture. To dissociate the somatosensory afferents from the compound acupuncture stimulus, two different experimental paradigms were used. Real acupuncture (REAL) induces both somatosensory afferent and contextual manipulation. A needle was inserted before the REAL scan, and one-second needle stimulations was performed 15 times during the REAL scan. Concurrently, visual cues were displayed to notify the participants of the needle stimuli (i.e., contextual manipulation). However, zombie acupuncture (ZOMB) only induced the somatosensory afferents. Participants were informed that an electrical measurement (i.e., no treatment) would be conducted with a visual cue, but they received needle stimuli in the ZOMB. We found diversity in the temporal characteristics of responses to somatosensory proxies. Brodmann area (BA) 3b, which receives ascending somatosensory signals in the cortex, showed a short latency of blood oxygenation level-dependent (BOLD) responses in REAL and ZOMB compared to the canonical double gamma-hemodynamic response. This phenomenon may be associated with the different types of inhibitory interneurons in BA 3b, which could establish the functional benefits of tactile discrimination. In the thalamus, the ventral posterolateral nucleus (VPL) and medial dorsal nucleus (MD) were associated with somatosensory afferents. VPL showed activity against both REAL and ZOMB, whereas MD showed activity only against ZOMB. Moreover, the responses of MD in the REAL scan were inversely correlated with the MASS index (i.e., De-qi, acupuncture-specific somatosensory sensation), suggesting that MD may be associated with an inhibitory mechanism of cognitive/affective processes. Study-2 tried to investigate the brain responses, focusing on the contextual manipulation of acupuncture, which led to cognitive/affective processes in the brain. To dissociate contextual manipulation from the compound stimulus of acupuncture, REAL and phantom acupuncture (PHNT) were performed on the same participant. PHNT induced needling credibility using only contextual manipulation of visual information in the stimulation scan, with verbal instruction in the preparatory scan. REAL conducted the actual needling stimulation in addition to the same protocol as PHNT. Thus, both REAL and PHNT induced cognitive/affective processes during acupuncture. Moreover, independent component (IC)-wise assessment separated brain responses to the contrasting experimental paradigms between REAL and PHNT into ICs. All BOLD data for REAL and PHNT were concatenated using ICA. Time series of ICs were used for the generalized linear model (GLM) with the stimulus paradigms of REAL and PHNT to assess stimulus- associated ICs (i.e., IC-wise GLM). IC-wise GLM revealed two ICs associated with both REAL and PHNT, which were identified as cognitive/affective processes for contextual manipulation: CA1, decision-making and executive process; and CA2, process for integration of multiple sensory afferents (e.g., vicarious sensation mechanism). Two ICs were associated only with REAL, which were identified as somatosensory afferent processes for the needle stimuli: SA1, a process for somatosensory representation and perception; SA2, an attentional process on the body (i.e., interoceptive attention); and an efferent process with the supplementary motor area. Moreover, the partial correlation network demonstrated a bidirectional connection of CA1 with SA1 and SA2, which was associated with a decrease in heart rate (HR) during needle stimuli for REAL. However, delayed HR decreased after needle stimuli and was only associated with CA1 for both REAL and PHNT. Furthermore, expectations of treatment were positively associated with CA1 in PHNT; however, expectations were positively associated with SA2 and negatively associated with CA1 in REAL. These relationships indicate that two different mechanisms of cognitive/affective processes are associated with the top-down pathway in acupuncture: an interactive process with somatosensory afferents (interoceptive attention) and a cognitive/affective-oriented process for delayed response (placebo mechanism). Study-3 tried to investigate the interactive processes of somatosensory afferents and contextual manipulation in the brain at the attentional stage. REAL, ZOMB, PHNT, and nonmeaningful visual information without needle stimuli (CONT) were conducted. To focus on the attentional process and distinguish it from the cognitive/affective response in the brain, the visual cue was displayed for a longer period (8 s) than the needling stimuli (1 s). Probabilistic ICA was performed for the concatenated BOLD using Bayesian dimensionality estimation techniques. In the IC-wise GLM, 2-way ANOVA assessed the ICs for the two stimulus components. We identified two ICs for the somatosensory afferents at the attentional stage (SA-A1 and SA-A2). In Study 2, SA-A1 was associated with the activation of brain regions for SA1 and CA1, indicating an interactive process between the SA1 and CA1. SA-A2 is associated with the activation of brain regions in the default mode network (DMN) and amygdala and deactivation of the anterior/agranular insula (aIns). A one-sample t-test of these ICs showed that SA-A1 positively correlated with somatosensory afferents. SA-A2 was inversely correlated with somatosensory afferents, indicating that somatosensory afferents inhibited DMN and amygdala activation, but facilitated aIns. In contrast, contextual manipulation at the attentional stage was associated with CA-A. CA-A is associated with the activation of brain regions for aIns and the periaqueductal gray (PAG), indicating an interaction between aIns and PAG. Thus, the CA-A suggests a differentiated mechanism for interoceptive attention with contextual manipulation. The facilitatory response of SA-A1 indicated brain processes for pain/nociceptive somatosensory input, whereas the inhibitory response of SA-A2 indicated interoceptive attention and DMN deactivation. Moreover, the partial correlation network for dual regression with these ICs showed a link between the MD weights for SA-A2 and CA-A, suggesting that SA-A2 and CA-A could be associated with the inhibitory mechanism of DM in Study-1 and the establishment of De-qi sensations. Furthermore, we found an interaction in the 2-way ANOVA between the two stimulus components (i.e., SA-CA-A), showing deactivation of the SA-CA-A in the ZOMB (deactivation without contextual manipulation only when needle stimulation was performed). Thus, the SA-CA-A is associated with the interactive process of somatosensory afferents in the cognitive/affective domain. This phenomenon also suggested that the brain processing of SA-CA-A was a part of that of SA-A1 and SA-A2 when the somatosensory afferent was present, and the absence of the somatosensory afferent might induce the deactivation of SA-CA-A. This dissertation demonstrates separate brain processes according to the two stimulus components of acupuncture. The brain processes included somatosensory representation for pain/nociceptive stimulus, dorsal and ventral attention networks for the confounding stimulus, interoceptive attention and efferent process, DMN deactivation with attentional process, and top-down control associated with the placebo mechanism. These multifunctional effects on the brain could differ depending on the effect of each tactile stimulus (e.g., painful stimulus) or expectation of treatment (e.g., placebo condition). Moreover, we found that cognitive interactions with these processes were associated with top-down mechanisms. Furthermore, the interactive processes via interoceptive attention were distinguishable from each process in the dorsal and ventral attention networks. Interoceptive attention to somatosensory afferents was associated with the interactive process between the multifunctional brain process of acupuncture and the establishment of De-qi sensation.

체감각 자극이 뇌손상 환자의 뇌기능 회복에 미치는 효과

김대란 연세대학교 대학원 2003 국내박사

본 연구는 임상현장에서 뇌손상으로 의식이 저하되어 있거나 마비가 있는 환자에게 사지를 '주무르거나 관절을 돌리는' 간호행위의 효과와 과학적 근거를 밝히고자 뇌손상으로 인해 전반적으로 뇌기능이 저하된 환자에게 손상초기 체감각 자극을 제공한 후 이것이 뇌손상 후 일어나는 자연적인 회복추세 이상의 회복효과가 있는지를 짝짓기 표출법을 이용한 대조군 반복측정 설계 방법으로 검증한 임상실험 연구이다. 총 연구기간은 12개월로 2002년 1월부터 4월까지 4개월간 체감각 자극 프로토콜을 개발하였으며 동년 5월부터 12월까지 8개월간 실험중재 및 자료수집을 실시하였다. 연구대상은 W시에 위치한 3차 종합병원 신경외과 중환자실에 입원해 있는 뇌손상 환자로 본 연구의 대상기준에 부합되는 환자 16명을 대상으로 하였으며, 실험군에게는 체감각 자극을, 대조군에게는 전통적인 간호중재만을 준 후 의식수준과 인지기능은 1주 간격으로 각 5회씩, 그리고 체성감각유발전위는 10일 간격으로 총 3회를 측정하였다. 수집된 자료는 SPSS/WIN 11.0을 이용하여 각 측정시점에서의 두 군의 차이는 Mann-Whitney U 검증법으로, 변화추세의 차이는 Repeated ANOVA로, 그리고 각 시점간의 전.후 비교는 Wilcoxon signed ranks test로 비교.분석하였다. 본 연구에서의 가설검증 결과는 다음과 같다. 1) 제 1가설: "체감각 자극을 제공받은 실험군이 제공받지 못한 대조군보다 의식수준 점수가 높을 것이다"는 체감각 자극 후 2주(U=10.000, p=.015), 3주 (U=1.500, p=.001), 4주(U=6.500, p=.004)가 되는 시점에서 각각 실험군의 GCS 점수가 대조군 보다 높은 것으로 나타나 지지되었다. 또한 의식수준의 변화추세 검증을 위한 추가분석에서도 두 군의 회복추세에 유의한 차이를 보여(F=4.136, p=.005) 실험군의 의식수준 회복추세가 대조군의 자연적인 회복추세보다 더 빠르게 나타났다. 2) 제 2가설: "체감각 자극을 제공받은 실험군이 제공받지 못한 대조군보다 인지기능 점수가 높을 것이다"는 체감각 자극 후 3주(U=2.000, p=.001), 4주(U=.000, p=.000)가 되는 시점에서 각각 실험군의 RLA 점수가 대조군보다 높은 것으로 나타나 지지되었다. 또한 인지기능의 변화추세 검증을 위한 추가분석에서도 두 군의 회복추세에 유의한 차이를 보여(F=14.320, p=.000) 실험군의 인지기능 회복추세가 대조군의 자연적인 회복추세보다 더 빠르게 나타났다. 3) 제 3가설: "체감각 자극을 제공받은 실험군이 제공받지 못한 대조군보다 감각유발전위검사상 나타나는 파형이 정상에 가까울 것이다"는 체감각 자극3주 후 실험군의 체성감각유발전위 파형점수가 대조군보다 높은 것으로 나타나 지지되었다(U=6.390, p=.017). 그러나 체성감각경로의 통합성의 변화추세 검증을 위한 추가분석에서는 두 군의 회복추세에 유의한 차이를 나타내지 않았다(F=2.193, p=.133). 이상의 연구결과를 요약하면 마사지와 관절운동으로 구성된 체감각 자극은 뇌손상 환자의 의식수준과 인지기능, 그리고 체성감각경로의 통합성 등 뇌기능 회복에 효과적인 것으로 나타났다. 또한 본 연구를 통해 의식이 저하된 뇌손상 환자에게 제공하는 간호중재로서의 체감각 자극의 적용에 대한 과학적 근거를 마련하였다. 본 연구에서 개발된 체감각 자극 프로토콜은 환자의 회복을 돕는 효과적인 중재로 활용할 수 있을 뿐만 아니라 환자의 건강회복 과정에 동참하기를 원하는 가족들에게도 유용한 교육자료로 이용될 수 있을 것이다. The purpose of this study was to determine the effect of a 3-week somatosensory stimulation program on functional recovery in the neuroplasticity of patients with brain damage. The sample consisted of two groups of patients with brain damage: 8 patients with a mean age of 54.6 years who were treated with somatosensory stimulation, and 8 patients with a mean age of 55.0 years matched for Glasgow Coma Scale (GCS) scores and age, who were not treated with somatosensory stimulation. A repeated measures matched-control group design with matched sampling method was used to assess functional recovery of the brain. The instruments used in this study were the GCS developed by Teasdale & Jennett, 1974) for consciousness level, RLA (Rancho Los Amigos Scale of Cognitive Function) developed by Rancho Los Amigos Medical Center for cognitive function, and SEP (somatosensory evoked potentials), a neurophysiological parameter, for the integrity of the somatosensory pathway. Data were collected from May to December, 2002 at a tertiary hospital in W city. The data collection time points were matched for both groups, at admission, and during the 3-week somatosensory stimulation program at four 1-week intervals for GCS and RLA, and at two 10-day intervals for SEP. The data were analysed using descriptive statistics, Mann Whitney U test, repeated ANOVA, and Wilcoxon signed ranks test with SPSS/WIN 11.0. The results are summarized as follows: Hypothesis 1 that "Patients with brain damage who were treated with the somatosensory stimulation program will show higher GCS scores than the non-treatment group." was supported (2nd week.: U=10.000, p=.015; 3rd week.: U=1.500, p=.001; 4th week.: U=6.500, p=.004). Additional repeated measures analysis showed that there were significant differences in recovery trends between the groups (F=4.136, p=.005). Hypothesis 2 that "patients with brain damage who were treated with the somatosensory stimulation program will show higher RLA scores than the non-treatment group." was supported (3rd week.: U=2.000, p=.001; 4th week.: U=.000, p=.000). Additional repeated measures analysis showed that there were significant differences in recovery trends between the groups (F=14.320, p=.000). Hypothesis 3 that "Patients with brain damage who were treated with the somatosensory stimulation program will show higher SEP wave form scores than the non-treatment group. was supported (3rd week.: U=6.390, p=.017). Additional repeated measures analysis showed that there were no significant differences in recovery trends between the groups (F=2.193, p=.133). In conclusion, this study demonstrates that a somatosensory stimulation program is very effective in promoting recovery of consciousness level, cognitive function, and the integrity of the somatosensory pathway of patients with brain damage.

Exposure to Music and Noise During Pregnancy Influences Neurogenesis and Thickness in Motor and Somatosensory Cortex of Rat Pups

Je Wook Shin 가천대학교 대학원 2016 국내석사

Exposure to Music and Noise During Pregnancy Influences Neurogenesis and Thickness in Motor and Somatosensory Cortex of Rat Pups Je Wook Shin Gachon University, School of Medicine (Directed by Professor Khae-Hawn Kim) Purpose Prenatal environmental conditions affect the development of the fetus. In the present study, we investigated the effects of exposure to music and noise during pregnancy on neurogenesis and thickness in the motor and somatosensory cortex of rat pups. Methods The pregnant rats in the music-applied group were exposed to 65 dB of comfortable music for 1 hour, once per day, from the 15th day of pregnancy until delivery. The pregnant rats in the noise-applied group were exposed to 95 dB of sound from a supersonic sound machine for 1 hour, once per day, from the 15th day of pregnancy until delivery. After birth, the offspring were left undisturbed together with their mother. The rat pups were sacrificed at 21 days after birth. Results Exposure to music during pregnancy increased neurogenesis in the motor and somatosensory cortex of rat pups. In contrast, rat pups exposed to noise during pregnancy showed decreased neurogenesis and thickness in the motor and somatosensory cortex. Conclusions Our study suggests that music and noise during the developmental period are important factors influencing brain development and urogenital disorders.

Neuromagnetic studies on cortical somatosensory and auditory functions in healthy subjects and patients with fibromyalgia

임만열 서울대학교 대학원 2014 국내박사

Introduction: Fibromyalgia (FM) is one of the prevalent chronic pain disorders characterized by widespread pain over entire body, and also often accompanied by affective and cognitive symptoms. The underlying cause of symptoms observed in FM remains still elusive, although centrally mediated augmentation of sensory and pain processing is a well-established pathologic mechanism in FM. This thesis aimed to investigate neurophysiological underpinnings of how patients with FM process non-painful sensory information with the following 2 studies. These themes are of particular importance in terms of understanding the neural mechanisms of somatosensory processing in the absence of noxious input and pre-attentive auditory processing in FM. Methods: The study enrolled 19 patients with FM and 21 gender-, age-, and education level-matched healthy controls (HC). Firstly, to investigate intracortical inhibition function in the primary somatosensory cortex (S1), paired-pulse median nerve stimulation was applied at the left and right wrist while recording magnetoencephalography. Paired-pulse suppression (PPS) was calculated as the ratio of the amplitudes of the second and the first responses in the S1, and then compared between FM and HC subjects. Secondly, to explore different characteristics of mismatch negativity (MMN), known as a neural marker for pre-attentive processing, between FM patients and HC, auditory evoked magnetic fields were recorded during a duration-deviant auditory oddball task (50-ms standard and 100-ms deviant tones). Peak latencies, amplitude, and directional asymmetry coefficient of the MMN responses were compared between two groups. Pressure pain threshold over the thenar and trapezius muscles was assessed for measuring pain sensitivity. Results: As a first study result, we have found that patients with FM exhibited greater PPS ratio in both hemispheres than pain-free HC, indicating less somatosensory inhibition. PPS in the left hemisphere was positively associated with both the sensory and affective dimension of clinical pain. Next, FM patients exhibited reduced MMN amplitude in the right hemisphere. Directional asymmetry coefficient of the MMN amplitude was lower in patients with FM, indicating more leftward asymmetry compared to HC. Smaller MMN amplitude in the right hemisphere was associated with lower pressure pain threshold of thenar muscle in FM patients. Conclusion: The present results are to demonstrate evidence of reduced somatosensory inhibition and suggest that reorganization of the S1 would be the underlying mechanism of subjective experience of pain in FM. In addition, our results suggest that pre-attentive auditory processing, reflective of cognitive function, may be compromised in FM. In conclusion, this study provides an explanation for electrophysiological mechanisms of abnormal somatosensory and auditory processing which might be related to pain sensitivity in FM. 배경: 섬유근육통은 만성적인 전신 통증과 신체 곳곳에 압통점이 나타나는 근골격계 질환으로, 섬유근육통 환자들은 통증과 더불어 우울감, 불안, 및 인지 능력 저하를 호소한다. 현재까지 중추 신경의 통증 처리계 이상이 질환의 병태 생리를 설명하는 유력한 가설로 지지 받고 있다. 하지만, 기존 연구들은 통증 자극에 따른 뇌 내 기능적 변화에 주로 초점이 맞춰져 있고, 일반 감각 자극에 대한 뇌 내 반응과 이에 대한 해석을 제시하는 연구는 거의 전무한 실정이다. 일반 감각 자극에 대한 뇌 내 반응에 대한 이유가 중요한 이유는 섬유근육통 환자들이 평소 특별한 자극이 없거나 혹은 무해한 자극에도 큰 통증을 느끼고, 소리나 빛과 같은 감각 자극에 대한 민감도도 증가해 있으며, 이러한 감각의 민감도가 통증의 민감도와 상관이 있기 때문이다. 이러한 배경을 바탕으로 이번 연구에서는 일반 감각 자극에 대한 일차 체성감각 피질의 억제성 반응과, 전 주의적 청감각 정보 처리를 반영하는 mismatch negativity (MMN)에 대해 연구하였다. 방법: 섬유근육통 환자군 19명과 성별, 나이, 교육 수준이 짝 맞춰진 정상 대조군 21명을 모집하여 체성감각과 청감각 유발 자계를 뇌자도를 이용하여 측정하였다. 체성감각 피질의 억제 기능을 평가하기 위해 먼저 정중신경에 전기적인 자극을 쌍으로 제시하여 첫 번째 자극에 대한 일차 체성감각 피질 반응의 크기와 두 번째 자극에 대한 반응의 크기 비 (쌍자극에 대한 억제 비)를 비교하였다. 또한, 전 주의적 청감각 정보 처리 평가를 위해 덜 빈번하게 제시되는 변이음과 빈번하게 제시되는 표준음에 대한 뇌 반응의 차이인 MMN 자계의 크기를 비교하였다. 결과: 먼저 체성감각 피질의 억제 기능 연구 결과로, 섬유근육통 환자군은 정상 대조군에 비해 쌍자극에 대한 억제 수준이 양쪽 반구에서 모두 감소해 있었고, 이것은 환자들의 임상적 통증 정도와 유의한 상관관계를 가졌다. 또한, 전 주의적 청감각 정보 처리 평가 연구 결과로, 섬유근육통 환자군은 정상 대조군에 비해 오른쪽 반구MMN 자계의 크기가 감소해 있었고, 이것은 압력 통증 역치와 정적 상관을 보였다. 결론: 연구 결과는 먼저, 섬유근육통 환자의 일차 체성감각 피질의 억제 기능이 감소되어 있다는 증거를 제공하며, 이것은 섬유근육통 환자의 일차 체성감각 피질의 재조직화가 임상적 통증과 밀접한 관계를 이룬다는 것을 말해준다. 또한, 연구 결과는 섬유근육통 환자의 전 주의적 청감각 처리 기능이 저하되어 있다는 증거를 제공한다. 종합하면 이번 연구를 통해 섬유근육통 환자에서 일반 감각 정보를 처리하는 체성감각 및 청각피질 기능 저하의 전기생리학적 수준의 설명을 제공한다.

가토에서 체성감각 유발전위(Somatosensory evoked potential)를 이용한 말초신경 재생에 관한 실험적 연구

한태륜 서울대학교 1985 국내박사