Human Cerebellar Activation during Painful Cold Stimulation:a Functional Magnetic Resonance Imaging Study

Seung-Schik Yoo,Byung Gil Choi,Chang Uk Lee,Bum Soo Kim. Su Jung Yoon,Soo Jung Lee,Tae Kim,Jung Jin Kim,Chul Lee,In Ho Paik 대한신경정신의학회 2001 신경정신의학 Vol.40 No.4

연구목적: 본 연구에서는 기능적 자기공명영상법(fMRI)을 이용하여 동통 한랭 자극 동안의 소뇌 활동정도를 알아보 았다. 방 법: 6명의 건강한 자원자들을 선발하여 1.5 Tesla MR scanner 안에 누워 있는 동안 그들의 좌측 손에 0~3℃의 얼음주머니를 올려놓아 동통 한랭 자극을 주었다. 자극과 연관된 BOLD(blood oxygenation level dependent) 반응을 평가하기 위해 일련의 susceptibility-weighted MR image를 측정하였고 대뇌활동 영 역을 시각화하고 정량화하는 statistical parametric map을 작성하였다. 결 과: 한랭 자극으로 인해 동통을 느끼는 동안 전/후 대상회전(cingulate gyri), 전두엽회(prefrontal gyri), 방사 섬이랑(insula)을 포함하는 대뇌영역뿐만 아니라, 네모소엽(quadrangular lobule), 널판소엽(gracile), 반월 소엽(semilunar lobules)과 같은 몇몇 소뇌영역이 활성화되었다. 결 론: 소뇌의 특정부위는 대뇌와 함께 동통 한랭 자극의 인지 및 처리과정에 관여하는 것으로 보인다. Objectives:We report a functional magnetic resonance imaging(fMRI) method for mapping human cerebellar activity during painful cold-stimulation. Methods:Six healthy volunteers experienced painful thermal stimulation induced by holding an ice bag(0-3C) in their left hand while lying still in 1.5 Tesla MR scanner. In order to capture the hemodynamic BOLD(blood oxygenation level dependent) response associated with the stimuli, a series of susceptibility-weighted MR images were acquired, and a statistical parametric map was generated to visualize and quantify the eloquent areas of brain activation. Results:In addition to cerebral areas including anterior/posterior cingulate gyri, prefrontal cortex, and insula, our results suggested that several cerebellar areas such as quadrangular lobule, bilateral gracile and semilunar lobules were involved in the experience of pain during cold stimulation. Conclusions:Human cerebellum, in addition to the cerebrum, is involved in the cognition and processing painful sensory stimulation

Transcranial focused ultrasound to the thalamus alters anesthesia time in rats

Yoo, Seung-Schik,Kim, Hyungmin,Min, Byoung-Kyong,Franck, Eric,Park, Shinsuk Lippincott Williams Wilkins, Inc. 2011 NEUROREPORT - Vol.22 No.15

A pulsed application of focused ultrasound (FUS) to the regional brain tissue alters the state of tissue excitability and thus provides the means for noninvasive functional neuromodulation. We report that the application of transcranial FUS to the thalamus of anesthetized rats reduced the time to emergence of voluntary movement from intraperitoneal ketamine/xylazine anesthesia. Low-intensity FUS was applied to the thalamus of anesthetized animals. The times required for the animals to show distinct physiological/behavioral changes were measured and compared with those times required in a control session without sonication. The sonication significantly reduced the time to show pinch response and voluntary movement. The modulatory effects of FUS on anesthesia suggest potential therapeutic applications for disorders of consciousness such as minimally consciousness states.

REPRODUCIBILITY OF TRIAL-BASED FUNCTIONAL MRI ON MOTOR IMAGERY

Yoo, Seung-Schik,O'Leary, Heather M.,Lee, Jong-Hwan,Chen, Nan-Kuei,Panych, Lawrence P.,Jolesz, Ferenc A. Informa Healthcare 2007 International journal of neuroscience Vol.117 No.2

<P> The investigation of the reproducibility in functional MRI (fMRI) is an important step in the quantification and analysis of paradigm-related brain activation. This article reports on reproducibility of cortical activation characterized by repeated fMRI runs (10 times) during the performance of a motor imagery and a passive auditory stimulation as a control task. Two parameters, the size of activation and BOLD signal contrast, were measured from regions-of-interest for 10 subjects across different threshold conditions. The variability of these parameters was normalized with respect to the mean obtained from 10 runs, and represented as the intrasession variability. It was found that the variability was significantly lower in the measurement of BOLD signal contrast as compared to the measurement of the size of activation. The variability of the activation volume measurement was greater in the motor imagery task than in the auditory tasks across all thresholds. This task-dependent difference was not apparent from the measurement of the BOLD signal contrast. The presence of threshold dependence in the variability measurement was also examined, but no such dependency was found. The results suggest that a measurement of BOLD signal itself is a more reliable indicator of paradigm-related brain activation during repeated fMRI scans.</P>

Functional magnetic resonance imaging-mediated learning of increased activity in auditory areas

Yoo, Seung-Schik,Lee, Jong-Hwan,O’Leary, Heather,Lee, Vivian,Choo, Seh-Eun,Jolesz, Ferenc A. Lippincott Williams & Wilkins 2007 NeuroReport Vol.18 No.18

Our earlier study indicated that functional magnetic resonance imaging (fMRI)-based detection and feedback of regional cortical activity from the auditory area enabled a group of individuals to increase the level of activation mediated by auditory attention during sound stimulation. The long-term ability to maintain an increased level of cortical activation, extending to a time period of a few weeks, however, has not been investigated. We used real-time fMRI to confirm the utility of fMRI in forming a basis for the regulation of brain function to increase the activation in the auditory areas, and demonstrated that the learned ability could be retained after a 2-week period, with additional involvement of an attention-related neural network.

In Vivo Visualization of White Matter Fiber Tracts of Preterm- and Term-Infant Brains With Diffusion Tensor Magnetic Resonance Imaging

Yoo, Seung-Schik,Park, Hae-Jeong,Soul, Janet S.,Mamata, Hatsuho,Park, HyunWook,Westin, Carl-Fredrik,Bassan, Haim,Du Plessis, Adre J.,Robertson Jr, Richard L.,Maier, Stephan E.,Ringer, Steven A.,Volpe, J.B. Lippincott 2005 Vol. No.

OBJECTIVE:: The goal of this study was to test the feasibility of visualizing a 3-dimensional structure of cerebral white matter fiber tracts in preterm infants, postconceptional age (PCA) 28 weeks to term, by using volumetric diffusion tensor magnetic resonance imaging (DTI) data. MATERIALS AND METHOD:: We combined tractography algorithms and visualization methods, currently available for adult DTI data, to trace the pixelated principal direction of a diffusion tensor originating from regions-of-interest with high fractional anisotropy. Consequently, white matter fiber bundles from the genu and the splenium of corpus callosum, the corticospinal tracts, the inferior fronto-occipital fasciculi, and optic radiations were visualized. RESULTS:: Our results suggest that major white matter tracts of preterm infant brains, with PCAs ranging from 28 weeks to term (40 weeks old), can be successfully visualized despite the small brain volume and low anisotropy. CONCLUSION:: The feasibility of fiber tractography in preterm neonates with DTI may add a new dimension in detection and characterization of white matter injuries of preterm infants.

Neural activities in human somatosensory cortical areas evoked by acupuncture stimulation

Yoo, Seung-Schik,Kerr, Catherine E.,Park, Min,Im, Dong-mi,Blinder, Russell A.,Park, HyunWook,Kaptchuk, Ted J. Elsevier 2007 Complementary therapies in medicine Vol.15 No.4

<P><B>Summary</B></P><P><B>Objectives</B></P><P>To investigate neural representation evoked by acupuncture from human somatosensory cortices, especially from primary (<I>SI</I>) and secondary (<I>SII</I>) somatosensory areas.</P><P><B>Design and setting</B></P><P>Neuroimaging study – Blood-oxygenation-level-dependent (BOLD) functional MRI was performed during acupuncture on <I>LI4</I> (<I>n</I>=12 healthy participants). Sham acupuncture and innocuous tactile stimulation were also applied on the same acupuncture site as control comparisons.</P><P><B>Outcome measures</B></P><P>Responsive neural substrates were visualized and identified based on both individual and group-level surface activation maps.</P><P><B>Results</B></P><P>Discrete regions within the precentral gyrus (area 4) and the fundus of the central sulcus (area 3a) were selectively activated during the real acupuncture stimulation. In <I>SII</I>, the activation was extended in a postero-inferior direction to the fundus of the lateral sulcus.</P><P><B>Conclusion</B></P><P>This specific pattern of acupuncture-related activation indicates that deep tissue stimulation (as seen in area 3a activation) and concurrent processing of sensory stimulation (as seen in activation in <I>SII</I>) may mediate neural responses to manual acupuncture.</P>

Neural Substrates of Motor Imagery : Event-related Functional MRI Study 관련 기능적 자기공명영상 연구

Yoo, Seung-Schik,Choi, Byung Gil,Chung, Kyu-In,Lee, Chang-Uk 大韓神經精神醫學會 2002 신경정신의학 Vol.40 No.6

연구목적 : 본 연구의 목적은 가상운동 과정 시 대뇌 어느 부위가 활성화되는지를 알아보기 위하여 사건-관련 기능적 자기공명영상을 통해 평가하였다. 방 법 : 9명의 오른손잡이 정상인들에게 뇌 전 영역을 포괄한 일련의 T2강조 자기공명 영상을 얻기 위해 1.5 Tesla 자기공명 영상장치를 사용하였다. 음성 자극 신호에 따라 오른손을 쥐는 상상을 하게 한 후, 그 결과 발생하는 가상 운동과 연관된 혈중 산화 수준-의존성 신호 변화들을 측정하였다. 결 과 : 측정된 자료를 group 분석한 결과 내측 상부 전두회, 설상엽, 도, 중/상부 측두회, 전대상회가 활성화 되었으며 이는 양측 일차운동영역, 전운동영역, 보조운동영역에서 사건-관련 자기공명 신호 변화가 있었음을 보여주었다. 또한 한 쪽 손만 쥐는 상상을 했을 때도 양측의 운동영역들이 활성화되었고 조가비핵, 창백핵, 시상 등의 피질하 부위도 활성화되었다. 결 론 : 본 연구 결과 가상운동에 의해 운동경로에 관여된 피질, 피질하 영역들이 시각화되어 가사운동이 실제 운동의 뇌신경 부위와 공유한다는 사실을 확인하였다. objectives : We report event-related functional magnetic resonance imaging(fMRI) methodology to investigate human brain activity during motor imagery. Methods : A 1.5 Tesla clinical MR scanner was used in the acquisition fo a sries of T2^* weighted MR images covering the whole brain. Blood oxygenation level-dependent(BOLD) signal changes assoiated with the imagery event were subsequently detected while healthy right-handed subjects imagined clenching of a right hand cued by auditory stimulus. Results : Group analysis across nine right-handed subjects revealed activations in the medial and superior frontal gyri, cuneus, insula, middle/superior temporal gyri, and anterior cingulate gyri. Bilateral primary motor, premotor and supplementary motor areas exhibited event-related MR signal change. Although unilateral hand clenching was imagined, bilateral activation of eloquent motor areas was observed. The proposed method also allowed for the visualization of subcortical areas, such as putamen, globus pallidus and thalamus, responsive to the event of motor imagery. Conclusion : The major cortical and subcortical areas in the motor pathways were identified and visualized during motor imagery event. Our results suggest that motor imagery and actual movement share common neural substrate.

BRAIN ACTIVATION RELATED TO AFFECTIVE DIMENSION DURING THERMAL STIMULATION IN HUMANS: A FUNCTIONAL MAGNETIC RESONANCE IMAGING STUDY

Sung, Eun-Jung,Yoo, Seung-Schik,Yoon, Hyo Woon,Oh, Sung-Suk,Han, Yeji,Park, Hyun Wook Informa Healthcare 2007 International journal of neuroscience Vol.117 No.7

<P> The aim of this study was to identify the activated brain region that is involved with the affective dimension of thermal stimulation (not pain, but innocuous warming) using functional MR imaging. Twelve healthy, right-handed male subjects participated in the study. Thermal stimulation with two different temperatures of 41°C and 34°C was applied to the subjects using a fomentation pack, wrapped around the right lower leg of each subject. On the basis of the subjects' responses after the scanning sessions, the authors were able to observe that the subjects felt "warm" and "slightly pleasant and comfortable" under the 41°C condition. The experimental results indicated that warm stimulation produced a significant increase of activation compared to thermal neutral stimulation in various regions such as contralateral insular, ipsilateral cerebellum, ipsilateral putamen, contralateral middle frontal gyrus, ipsilateral inferior frontal gyrus, contralateral postcentral gyrus, and contralateral paracentral lobule. The activated regions are known to be related to thermal sensory, affective/emotional awareness, cognitive functions, sensory-discrimination, and emotion/affective processing, and so on. These results suggest that an appropriate thermal stimulation can produce a positive emotion and activate emotion/affect related regions of the brain.</P>

Verbal working memory dysfunction in schizophrenia: an FMRI investigation.

Pae, Chi-Un,Juh, Rahyeong,Yoo, Seung-Schik,Choi, Byung-Gil,Lim, Hyun-Kook,Lee, Chul,Paik, In-Ho,Jeun, Sin Su,Lee, Chang-Uk Gordon and Breach 2008 INTERNATIONAL JOURNAL OF NEUROSCIENCE - Vol.118 No.10

<P>Impaired processing of working memory information is one of the cognitive deficits seen in patients with schizophrenia. This study aims at corroborating the differences in the brain activities involved in the process of working memory between patients with schizophrenia and the controls. Twelve patients with schizophrenia and 11 controls participated in the study. Functional magnetic resonance imaging (fMRI) was used to assess cortical activities during the performance of a two-back verbal working memory paradigm using the Korean alphabet as mnemonic content. Group analysis revealed that inferior fontal, middle frontal, and superior temporal region showed decreased cortical activities in the patient group compared to those of the controls. This study showed a decreased activation in inferior fontal (BA 47), middle frontal (BA 6), and superior temporal (BA 22/38) neural networks from the patient group and confirmed the earlier findings on the impaired working memory of schizophrenic patients in the fMRI investigation.</P>

Prototype Modular Capsule Robots for Capsule Endoscopies

Laehyun Kim,Sai Chun Tang,Seung-Schik Yoo 제어로봇시스템학회 2013 제어로봇시스템학회 국제학술대회 논문집 Vol.2013 No.10

Capsule endoscopy allows clinicians to wirelessly examine the small intestine using a capsule equipped with a miniscule camera. However, it has intrinsic limitations such as a lack of controlled capsule locomotion and limited therapeutic functions inside the gastrointestinal (GI) track. Recently, several researches have been conducted to prototype robotic capsules that have a self-propelling mechanism by integrating modern technologies. To routinely use in a clinical setting, several technical challenges, including size constraint of the capsule, locomotion mechanism, and stable power source, should be addressed. In this paper, we introduce a prototype of a modular robotic capsule system, which is designed to distribute the functional burdens among multiple robotic capsule modules. For example, active locomotion can be achieved via a collaborative actuation among multiple modules after self-assembly. This novel design was also supplemented with inductive power transmission techniques to wirelessly power the modules. The presented modular, miniature robotic platform may provide a new paradigm for developing multi-function capsule endoscope, with future implications in minimally invasive surgery.