San DiegoにてNeuroscience 2016が開始されました。
我々のグループから、下記の3件の発表を行います。
Graph theoretical analysis of functional
connectivity network during breath-counting mindfulness meditation. S. HIWA*; M. IIZUKA; T. HIROYASU.
Doshisha Univ., Doshisha Univ.
Development and discussion of dti phantom for nerve fiber tracking. S. YOKOYAMA*; T.HIROYASU; S. HIWA.
Doshisha Univ.
An fNIRS study of cooperativeness during synchronized tapping task. A. MURAKAMI*; H. YOKOUCHI; S. HIWA; T. HIROYASU.
Doshisha Univ
学会参加報告書
| 報告者氏名 | 村上晶穂 |
| 発表論文タイトル | fNIRSを用いた同期タッピング課題時の協調性の検討 |
| 発表論文英タイトル | An fNIRS study of cooperativeness during synchronized tapping task |
| 著者 | 村上晶穂, 横内久猛, 日和悟, 廣安知之 |
| 主催 | Society for Neuroscience |
| 講演会名 | NeuroScience2016 |
| 会場 | San Diego convention center |
| 開催日程 | 2016/11/12-2016/11/16 |
- 講演会の詳細
2016/11/12から2016/11/16にかけて，San Diego convention centerにて開催されましたNeuroScience2016 (https://www.sfn.org/annual-meeting/neuroscience-2016)に参加いたしました．この学会は，脳と神経システムに関する世界最大規模の組織であるSociety for Neuroscienceによって主催されているものです．生体に関する研究全般を対象とした，80以上の国から3万人ほど参加する規模の大きい学会です．
私は全ての日程に参加いたしました．本研究室からは他に日和先生，横山さんが参加しました．
- 研究発表
- 発表概要
私は13日の13-17時のセッション「Poster」に参加いたしました．発表の形式はポスター発表で，発表時間は1時間でした． 今回はAn fNIRS study of cooperativeness during synchronized tapping taskというタイトルで発表しました．以下に抄録を記載致します．
| 【Introduction】Communication is an important process for our human beings. Especially, the ability to behave in adapting to others’ feelings and willingness is referred to as cooperativeness. Higher cooperativeness allows us to communicate with others better and understand each other easier. Cooperativeness varies between different people, and the brain activities when we have an interaction with others have not been investigated well. If the relation between cooperativeness and the brain activities would be revealed, it may help diagnosis and treatment of communication disorders. Our goal of this study is to examine human brain activity during cooperative work. In this paper, we investigated the brain activity during human-machine cooperative work as a preliminary study for human-human cooperative work. We discussed how human processed the information from others and determined their behaviors. 【Method】 Cooperativeness is often associated with synchronization with others. Therefore, a synchronized tapping task between a subject and a machine has been applied to investigate a mechanism of human predictive behavior for synchronization. In this task, the subject attempted to synchronize a button press with an auditory stimulus. The stimulus intervals were periodically changed. Sixteen healthy male subjects participated in this experiment, and their cerebral blood flow changes were measured using functional near-infrared spectroscopy (Hitachi ETG-7100). Furthermore, social skills of the subjects were evaluated using a questionnaire called KiSS-18. 【Result & Discussion】 We analyzed their task performances using synchronization error (SE) calculated by a time difference between auditory stimulus and tap interval. The average of time-course SE of all subjects indicated that they could adapt to the change of rhythm within a few times of tapping. From the data of blood flow changes, regions which were activated among over 80 percent of subject were the DLPFC in frontal region and the angular gyrus in left temporal region. The subjects were divided into high-performance (3 subjects) and low-performance (3 subjects) groups based on KiSS-18 scores, and the activated regions differed between the groups. When the rhythm of a stimulus is changed, people attempt to adjust timing to the changed rhythm. It is reported that the angular gyrus has the function of recognition and the DLPFC have the function of behavior control. Our results suggest that the subjects recognized the change of rhythm and controlled behavior of tapping to adjust timing to the changed rhythm.【Conclusion】 It was suggested that cooperativeness could be associated with DLPFC and angular gyrus. |
- 質疑応答
今回の講演発表では，以下のような質疑を受けました．
・質問内容
質問内容1
質問者の氏名を控え損ねてしまいました．ヒト-ヒトとヒト-機械で何が違うのか．なぜヒト間で実験をしないのかという質問でした．これに対して，ヒト-ヒトでは協調性以外の要素が含まれている．そのためヒト-ヒトの前段階として協調性以外の要素をなるべく取り払ったヒト-機械の実験を行っているとお答えしました．
質問内容2
質問者の氏名を控え損ねてしまいました．こちらの質問は協調性と課題の関係は何かというものでした．これに対して，協調性にはタイミングを合わせることが大切で，タイミング機構を調べる課題として用いられる同期タッピング課題を本実験では使用したとお答えしました．
質問内容3
質問者の氏名を控え損ねてしまいました．こちらの質問はグループによる行動データの違いはあるのかというものでした．これに対して，音刺激とタップ動作の時間差であるSEをグループごとに算出したデータを見せながら，行動データに差はないとお答えしました．
- 感想
2度目の国際学会での発表であったこともあり，それほど緊張せずに臨むことができました．予想よりも多くの方に私の発表を聞いてくださり，結果がおもしろいと言ってくださったことがうれしく思いました．英語での研究内容の説明や質疑応答は，うまく説明できず，もどかしく思うところもありましたが，それも良い経験になったと思います．今後の修士論文作成にあたっても貴重なご意見や質問をいただきことができ，大変勉強になりました．
- 聴講
今回の講演会では，下記の5件の発表を聴講しました．
| 発表タイトル ： Hyperscanning study on synchronized singing between two people using fNIRS著者 ： N. OSAKA, T. MINAMOTO, K. YAOI, M. AZUMA , M. OSAKA セッション名 ： Poster Abstract ： Our brain have been developed to communicate with others, however it seems unclear how our brain achieves interactive communication. Here, we report the neural synchronization for singing and humming between two people, simultaneously measuring two brain activities using an fNIRS-based hyperscanning. Using a functional near-infrared spectroscopy (fNIRS), brain activity of two peoples was measured while they performed a cooperated humming or singing with face-to-face and face-to-wall (preventing them from observing other’s face by a wall). The results showed a significant increase in the neural synchronization in the left inferior frontal cortex (IFC) in both the singing and humming regardless of existence of the wall, in comparison to the single singing/humming. On the other hand, the right IFC showed an increase in the neural synchronization during humming but not singing, possibly due to higher dependence on musical processing. Those results suggest a usefulness of the fNIRS-based hyperscanning in natural social interaction. |
この発表は2人の脳を同時にfNIRSで計測しているハイパースキャン研究で，2名間でハミング/歌っている時の神経活動を検討していました．右のIFGのコヒーレンスがハミング時に上昇しているという結果でした．そして，自然な社会的相互作用におけるfNIRSを用いたハイパースキャン研究の有用性を示していました．解析方法や着目部位など，ヒト-ヒト間で実験する際に参考になると思いました．
| 発表タイトル ：Verbal and nonverbal communications convey distinct emotional qualities through shared neural circuitry著者 ： R. ROJIANI, X. ZHANG, A. NOAH, J. HIRSCH セッション名 ： Poster Abstract ： Little is known about the underlying brain organizations that mediate verbal and nonverbal communication of emotion, in part due to the inability of current data acquisition systems to emulate natural conditions. Such direct communication and its relationship to emotional salience can be investigated with simultaneous acquisitions of BOLD signals from two interacting subjects using functional near-infrared spectroscopy (fNIRS), offering significant ecological validity. In this study, we test the hypothesis that verbal and nonverbal modes of communication differ in their capacity to send and receive emotional qualities such as valence and arousal. BOLD signals reflecting concentrations of deoxy-hemoglobin (comparable to fMRI signals) were acquired using a whole-head fNIRS system consisting of 84 channels divided evenly between two interacting subjects with a Shimadzu LABNIRS system. Dyads of 36 subjects participated two conditions of communication: verbal (dialogue) and non-verbal (drumming), each using alternating 15 sec epochs of “sending” (drumming or talking to partner) and “receiving” (listening to partner). In each 15 sec epoch, both partners were presented with the topic of communication: a photo from a pseudorandomized subset of the International Affective Picture System (IAPS). Emotional qualities of the topics were subdivided into valence (happy versus unhappy) and arousal (excited versus calm), which have been quantified for each photo by IAPS. When collapsing across verbal (talking) and nonverbal (drumming) communication conditions, general linear model (GLM) contrast comparisons of valence and arousal both revealed peak neural activity in the Right Superior Temporal Gyrus (rSTG) – a canonical social- and emotion-sensitive area of the brain (p<0.05). Contrast comparisons further revealed that during the talking condition, a cluster in the rSTG (68, -40, 22) shows increased sensitivity to positive valence over negative valence (p<0.05). In contrast, during the drumming condition, the same region of rSTG shows increased sensitivity to high arousal over low arousal (p<0.05). This natural dual-brain communication paradigm reveals a neural specificity for processing varied emotional qualities regardless of verbal or nonverbal form. Further, these findings suggest that modes of communication vary with respect to conveyance of emotional qualities; talking is optimized for valence, while drumming is optimized for arousal. Given the rising popularity of non-traditional modes of clinical therapy (e.g. drum circles for PTSD), this novel finding offers a neural basis for future research to optimize clinical care in mental health. |
この発表は感情とコミュニケーションの関係を検討していました．課題は2名のペアで行われ，IAPSの写真を見せた時に会話(言語的コミュニケーション)もしくはドラムを叩く(非言語的コミュニケーション)際の脳活動を計測していました．感情の質の伝達に関してコミュニケーションの様式が異なることを示唆していました．私の研究においても，実験を行っている時の心情を調査する必要性があると感じました．
| 発表タイトル ：Effects of a virtual reality (VR)-based functional near-infrared spectroscopy (fNIRS) neurofeedback (NF) intervention on highly-impulsive college students.著者 ： J. HUDAK, F. BLUME, T. DRESLER, C. GAWRILOW, セッション名 ： poster Abstract ：We conducted an electromyography (EMG) – controlled randomized functional near infrared spectroscopy (fNIRS) neurofeedback (NF) experiment set inside of a virtual classroom using the Oculus Rift head mounted display. The experiment was novel in its use of a virtual classroom, its intensive and truncated design, and its use of a sub-clinical population of highly impulsive college students. Designed as a pilot study preceding a much larger study with schoolchildren with attention deficit hyperactivity disorder (ADHD), we wanted to test the effects of the intervention on a population of healthy adults displaying parts of the ADHD phenotype (high impulsivity) and many of the neuropsychological characteristics underlying the disorder. We designed a virtual classroom in which the overhead lighting was controlled by means of the subjects’ dorsolateral prefrontal cortical (dlPFC) oxygenated hemoglobin (O2Hb) concentration relative to a baseline conducted before each trial. When subjects increased O2Hb concentration, i.e. activated their prefrontal cortex, then the light brightened; it darkened with deactivation. N = 20 subjects underwent eight training sessions across two weeks: n = 10 subjects were included in the treatment group while n = 10 subjects were in the control group and used their m. supraspinatus muscles to control the lighting. These training sessions were bookended by a pre and posttest in which we measured fNIRS O2Hb average amplitudes in front-temporal areas on two executive functioning tasks: a go/no-go and an N-back task. Additionally, the subjects performed a stop-signal task for behavioral data analysis. Emphasis during the first week of training was on learning the neurofeedback paradigm. In the second week, activation/deactivation ratio increased from 50 to 80%, in an attempt to train the implicit activation of the dlPFC in classroom situations. Results indicated a significant reduction in commission errors (impulsive false alarms) on the go/no-go task with a simultaneous increase in prefrontal O2Hb concentration, for the treatment group but not for the control group. In addition, treatment subjects showed a reduction in reaction time variability on the stop-signal task. These results indicate a clear effect of the NF intervention in reducing impulsive symptoms. This is especially encouraging because the design contained comparatively few sessions and significant results were obtained for a small pilot sample. We expect even better results with a clinical, and child population. |
この発表は，fNIRSを用いて多動性障害の人におけるNeurofeedback(NF)の検討を行っていました．結果から，NF介入によって症状の軽減の効果を示していました．Training群は通常2Dで行われることが多いですが，この研究ではVRを用いて3Dで行われていることが新しいと思いました．
| 発表タイトル ：Executive control of walking in adults with mobility deficits quantified by fNIRS neuroimaging著者 ： K. A. HAWKINS , E. J. FOX, J. J. DALY, D. K. ROSE, E. A. CHRISTOU, D. M. OTZEL, K. A. BUTERA, S. A. CHATTERJEE , D. J. CLARK セッション名 ： Poster Abstract ： Background: Control of walking involves a balance between “automatic” (primarily sub-cerebral) and “executive” (cerebral) control strategies. Executive control has a major role in real-time gait adaptations and may also serve an additional compensatory role for control of basic walking if automaticity is impaired. This compensation could compromise the safety of walking because executive control is attention demanding, slow, and susceptible to interference. New insights into the executive control of walking are possible with the use of functional near infrared spectroscopy (fNIRS), which allows for cortical neuroimaging during natural movements. We hypothesize that individuals with mobility deficits will exhibit greater reliance on executive control during walking, as measured by prefrontal cortex activation. Methods: Participants included 14 adults post-stroke with moderate/severe mobility deficits, 15 elderly adults with mild mobility deficits, and 9 young healthy adults. fNIRS was used to measure prefrontal cortex activation during four walking tasks: typical walking, walking over obstacles, walking in dim lighting, and a dual-task condition of walking plus a verbal fluency task. Participants with stroke were also assessed with the Activities Specific Balance Confidence Scale and the Fugl-Meyer Assessment of lower extremity function. Results: Prefrontal activity during walking showed a main effect of group (p elderly > young. Furthermore, lower functioning stroke participants exhibited greater prefrontal activity than higher functioning stroke participants when subgroups were defined by either the Fugl-Meyer score (p=0.011) or the balance confidence score (p=0.006). Prefrontal/executive reserve capacity, as quantified by the difference in prefrontal activity between dual-tasking and typical walking, was lower in the elderly and post-stroke participants (p=0.003). Conclusions: Executive control of typical and complex walking tasks is increased in individuals with mobility deficits, as indicated by greater prefrontal cortical activity. Increased use of executive control is likely a compensation for impairment in neural circuits of locomotor automaticity. Assessing locomotor control strategies with fNIRS is a promising direction for objective assessment of impairment and recovery in humans with mobility deficits. |
この発表は，fNIRSを用いて運動障害がある人の歩行制御時の脳活動を検討していました．歩行タスクの実行機能は運動障害のある人において増加し，前頭前野皮質の活動も大きいという結果でした．今後どのように客観的評価を行うのかが興味深いと思いました．
| 発表タイトル ：Comprehension-dependent cortical activation during speech comprehension tasks with multiple languages: functional near-infrared spectroscopy (fNIRS) study著者 ： M. LEI, T. MIYOSHI, Y. NIWA, I. DAN, H. SATO セッション名 ： Poster Abstract ： With the aim of investigating cerebral hemodynamics during auditory language comprehension, we measured brain activation of 46 normal right-handed Japanese adults with functional near-infrared spectroscopy (fNIRS) while performing speech comprehension tasks. In the experiment, a picture and four statements were given as stimuli to a subject, and the subject was asked to choose a statement that correctly describes the picture. Statements were given in three languages: English (second language), Japanese (native language), and Chinese (unknown language). Significant differences of oxygenated-hemoglobin (oxy-Hb) activations are found among three different languages particularly in the left hemisphere. Moreover, particularly in the English tasks, there are significant differences in oxy-Hb activations between the case when subjects correctly answered questions and the case when they didn’t. These results suggest that hemodynamic response differ in whether a subject understands given speeches or not. |
この発表は，fNIRSを用いて音声理解の際の脳活動を調べていました．母国語が日本語である人が被験者で，課題は英語，日本語，中国語の3つの言語を用いて実験を行っていました．結果は被験者が与えられた言語を理解するか否かにおいて脳機能が異なることを示していました．同じfNIRSを用いた研究だったので，前処理の仕方や着目部位の決め方が参考になりました．
参考文献
- Neuroscience2016
https://www.sfn.org/annual-meeting/neuroscience-2016
学会参加報告書
| 報告者氏名 |
横山宗平 |
| 発表論文タイトル | 神経線維追跡のためのdtiファントムの開発と議論 |
| 発表論文英タイトル | Development and discussion of dti phantom for nerve fiber tracking |
| 著者 | 横山宗平，日和悟，廣安知之 |
| 主催 | Society for Neuroscience |
| 講演会名 | Neuroscience2016 |
| 会場 | San Diego Convention Center |
| 開催日程 | 2016/11/12-2016/11/16 |
- 講演会の詳細
2016/11/12から2016/11/16にかけて，San Diego Convention Centerにて開催されましたNeuroscience20161)に参加致しました．このNeuroscience2016は，Society for Neuroscienceよって主催された研究会で，学生と教員が参加して，神経科学に関する学術的な発見を目的に開催されています．
私は全日参加いたしました．本研究室からは他に日和先生，村上さんが参加しました．
- 研究発表
- 発表概要
私は15日の午後のセッション「Optical Method：Real-Time Imaging」に参加いたしました．発表の形式はポスター発表で，1時間の講演時間となっておりました．
今回の発表は， kissing走行を模擬した2種類のファントムを作成して神経追跡結果を検討した内容を発表しました．以下に抄録を記載致します．
| In this paper, the DTI-phantom which was developed for evaluating fiber tracking methods was discussed. Recently diffusion tensor fiber tracking shows many suggestions for analyzing brain functions. However, diffusion tensor fiber tracking methods have several defects and they have to be resolved. Real detailed structure of nerve fiber in brain is unknown and nerve fiber phantoms should be utilized for evaluating fiber tracking methods. In the previous study the phantom which is consisted of Dyneema fiber whose thickness diameter is 15 [μm] was proposed. The thickness of the nerve fiber in brain is 0.2[μm] to 20[μm] in diameter. Thus, Dyneema fiber is a little thick to simulate nerve fiber. In this research, fibers who has hollows and whose thickness is 5.4 [μm] was used for the phantom. In the experiment, the developed phantom was used to evaluate the fiber tracking methods. The fiber diameter for phantom is 5.4 [μm] and the phantom fascicle was consisted of 12 million fibers. Two straight phantoms which were made of hollow fibers and Dyneema fibers were compared to measure the performance of hollow fibers. Then kissing phantom was also developed. Kissing structure is often observed in brain and two bundled nerve fibers are touching together. Since this two bundled fibers are kissing at one point, tracking method often tracks in wrong directions. The simple kissing phantom whose two fibers are just touched has already been proposed. In this research, kissing phantom whose bundled fibers were touched intertwined and this structure is much more similar to real brain nerve structure. This phantom was called meshed kissing phantom. The simple and meshed kissing phantoms were developed and the fiber tracking algorithm was applied to the measure DIT results. The results were compared and discussed. The results of different types of two straight phantoms were compared. Then the performance of the phantom which was consisted of hollow fibers showed the higher ability to express the nerves. The results of two different types of kissing phantoms showed the differences. In the meshed kissing phantom, a lot of tracking were occurred. This result described that the meshed kissing phantom is much more similar to real brain nerves compare to the simple kissing phantom. In this research, DTI phantom whose fiber diameter is 5.4 [μm] which is similar to real nerve fiber and who has hollows were developed and discussed. Then, DTI phantom which has kissing structure was also developed and measured. From the experiments, results showed that the developed DTI phantom can be used for evaluating fiber tracking methods. |
- 質疑応答
今回の講演発表では，以下のような質疑を受けました．
・質問内容1
質問者の氏名を控え損ねてしまいました．こちらの質問は作成したファントムの構造がどのようになっているのかというものでした．この質問に対してファントムは線維を束ねた構造に成っていることを写真を用いて説明しました．
・質問内容2
質問者の氏名を控え損ねてしまいました．この質問に対する回答ですがこのポスターの結論は何かというものでした．この質問に対して作成したkissingファントムがシンプルなkissingファントムより誤追跡が生じやすいため，kissing走行に対する追跡手法の評価が可能なファントムができたと説明しました．
- 感想
今回，Neuroscience2016で学会発表を行って，非常に良い経験をさせていただきました．まず，英語で発表する難しさを実感しました．発表前に準備を行った内容より初歩的なことを英語で説明できず，あまり納得していただけなかったことが残念でした．発表を聴講した感想として，DTIファントムの研究がなかったので，DTIを用いた発表を中心に聴講していました．質問した内容に対して説明していただいきましたが，最低限しか理解できずそれ以上の議論ができなかったことも残念でした．また，DTIを用いた研究は多かったのですが，神経追跡をした研究は少なく，最新の研究でも神経追跡があまり使用されていないことを認識しました．
今回の非常に後悔の多い学会参加となってしまいましたが，この経験を糧に研究，英語ともに頑張っていきます．
- 聴講
今回の講演会では，下記の2件の発表を聴講しました．
| 発表タイトル ： White matter and functional connectivity changes in MPTP nonhuman primates(Cercopithecus aethiops) model using fMRI and DTI 著者 ： G. RAMÍREZ GARCÍA セッション名 ： Parkinson’s Disease：Cell and Circuit Mechanisms Abstruct ： The analysis of blood-oxygen-level dependent (BOLD) signals obtained with functional magnetic resonance imaging (fMRI) allows inferring neuronal activity patterns for cognitive and motor processes. However, it is also possible to analyse BOLD signals at rest, a kind of analysis that has been termed resting-state fMRI (RS-fMRI). It examines the synchrony of the temporal BOLD signal between anatomically separated brain regions (networks) without the subject performing any particular task. This functional connectivity analysis differs from the traditional white matter structural connectivity analysis which is mainly done with Diffusion Tensor Images (DTI). Both techniques have been used to evaluate changes in patients with neurodegenerative disorders like Parkinson’s disease, in which the nigro-striatal-cortical dopaminergic pathway is affected causing motor and cognitive impairments. The aim of this work was to evaluate the functional connectivity in the resting state networks, as well as the structural connectivity, in green monkeys (Cercopitecus aethiops: n=3 per group) in basal conditions and after MPTP administration. RS-fMRI and DTI images were acquired in a GE Discovery MR750 (General Electric, Milwaukee, WI) 3T whole-body MR scanner. The animals were anesthetized with Tiletamine/Zolazepam 125/125 mg at dose of 2 mg/kg body weight (im). The DTI sequences consisted of Single Shot Echo Planar Imaging sequences, acquiring 65 volumes of 26 axial slices (2 mm slice thickness and no separation), one for each of the 60 independent directions of diffusion with b= 2000 s/mm2 and five corresponding to b=0 s/mm2. The functional connectivity networks were created using two methodologies, first using independent Component Analysis (ICA) and second the seed-based methodology, placing anchor seeds in different regions of the striatum. White matter changes were evaluated with the FSL Tract-Based Spatial Statistics tool. We found 6 networks at rest in the healthy subjects: somatomotor, frontal, default mode, primary visual medial cerebellar and visual networks. After the administration of MPTP, we found a decrease in the activation of striatal networks (caudate and putamen) and a decrease in white matter tracts of the internal and external capsules, corpus callosum and cerebellum. The results show the presence of six resting-state networks in greenmonkeys that can be analogous to functional networks previously characterized in humans. Decrease of striatal functional connectivity and white matter tracts are congruent with the loss of cortico-striatal communication due to the death of dopaminergic neurons in the striatum. |
この発表はパーキンソン病が脳に及ぼす影響を検討した発表でした．研究方法としてパーキンソン病を発症させるMPTPを猿に投与することで，脳の機能的ネットワークと構造的ネットワークを解析していました．猿と人の脳は構造的に違いがほとんどないため，今回の発表の結果が人の患者と同じであれば非常に面白い発表だと思いました．
| 発表タイトル ：Fractional anisotropy decrease at extended segments in the left arcuate fasciculus in people who stutter 著者 ： Keiichi Yasu セッション名 ： Cortical Mechanisms of Language Abstruct ： The left arcuate fasciculus connects motoric and perceptual language systems and the left ventral premotor and motor cortex. In people who stutter (PWS), the fractional anisotropy (FA) of the white matter is reduced in the left arcuate fasciculus near the ventral motor cortex related to speech (Sommer et al., 2002; Chang et al., 2008; Watkins et al., 2008; Cykowski et al., 2010, Connally et al., 2014, Cai et al., 2014). Among these studies, however, the areas of significant FA reduction were subtly different. In this study, the whole-brain fractional anisotropies (FA) were calculated from the diffusion weighted magnetic resonance imaging (DWI) of 64 directions and of no DWI (b0) acquired with a 3.0 T scanner (Skyra, Siemens) using a 64-channel head coil. FMRIB’s Diffusion Toolbox (FDT) in the FMRIB Software Library (FSL, FMRIB, Oxford, UK) was used for analysis. Tract-based spatial statistics of FA was applied to the whole comparison between the two groups. During preprocessing, brain-edge artifacts were removed. All FA images were aligned and registered to the standard space. After creating the mean 3D image of all the FA images, a skeletonizing mask was created with the threshold of 0.3. Two-group voxel-wise unpaired t-test was applied to the masked (skeletonized) FA data of the PWS and control subject groups. More elongated segments (up to 30 mm) of significantly decreased FA (p < 0.05, corrected) was found near the operculum and the angular gyrus (AG) in the left superior longitudinal fasciculus (SLF) than previously reported. The present results indicate that the somewhat inconsistent localizations of decreased FA in previous studies are parts of the more elongated segments of decreased FA in the left arcuate fasciculus. The decreased FA near the presumed mental lexicon area (AG) is likely to correspond to the decreased functional activation around this area in PWS (Mori et al., J Phon Soc Jpn, 20:61, 2016) and may explain the stuttering symptoms with familiar words. |
この発表では吃音症の原因解明のためFA値を用いた研究でした．従来の研究とは違い初めて日本人を対象としたものでした．吃音症の割合は世界共通とのことでしたが，従来の結果と異なる部分があったので，主要言語によって原因が異なることが判明したら面白いと思いました．
| 発表タイトル ： Diffusion Tensor Imaging detects alterations in the corpus callosum after mild TBI in the mouse 著者 ： P. N. Venkatasubramanian セッション名 ： Neurodegenerative Disorders and injury Abstruct ： Mild TBI is thought to induce axonal injury which might progress to chronic traumatic encephalopathy, post-traumatic stress syndrome, major depression and other pathological states. Using high resolution diffusion tensor imaging (DTI), we have investigated changes in brain microstructure in a mouse model of mild TBI and found changes in the corpus callosum (CC) that suggest chronic axonal injury. Male 7-8 week-old C57BL/6 mice were fixed in vertical position, heads down, in an aluminum shock tube with their back oriented towards the exit plane of the tube and hit with a supersonic helium wave at a peak reflective pressure of 70psi. On Days 2, 5 and 12 after the blast, the mice were cardiac-perfused and their brains removed for DTI at 14.1T. Multi-slice DTI of fixed brain was acquired using a spin-echo diffusion weighted pulse sequence: 59 μm x 59 μm in-plane, 0.5mm slice thickness, TR/TE 2500ms/16.5ms, duration of diffusion gradients 3ms, delay between diffusion gradients 7ms, 30 gradient directions and one b value = 1000 s/mm2. Resulting images were processed to generate maps of fractional anisotropy (FA). Diffusion parameters measured from medial and lateral CC in slices containing the genu (CCg), body (CCb) and splenium (CCsp) of CC were compared between controls and mTBI mice on Day 2 (n=3), Day 5 (n=4) and Day 12 (n=3). High resolution DTI revealed subtle, region-specific changes in the CC at different time points after injury. On Day 2, FA was lower in both medial and lateral CCb (0.41±0.01 and 0.40±0.02, respectively) relative to controls (0.46±0.02 and 0.44±0.01) indicating axonal injury in CC after blast injury. CCg and CCsp showed no changes in FA on Day 2. Reduced FA values indicated axonal injury on Day 2, whereas in preliminary experiments enhanced tau phosphorylation was found only on Day 5. DTI showed that on Day 5, FA was higher in medial and lateral CCg (0.60±0.02 and 0.56±0.01 in mTBI vs 0.55±0.01 and 0.49±0.02 in controls), as well as in medial CCb (0.50±0.02). Increased FA was associated with increase in diffusivity along the fiber direction (axial diffusivity) and no change in radial diffusivity. The observed increase in FA might represent axonal compression. On Day 12, FA in CCg and CCb returned to normal values, whereas it decreased in medial CCsp (0.48±0.03 vs 0.55±0.02 in control) indicating that mTBI likely results in chronic structural changes in the CC. Our blast injury model appears to be a useful paradigm to investigate mTBI in mice. High resolution DTI reveals region-specific, chronic mictrostructural changes following mTBI in mice. |
この発表は軽度な外傷性脳損傷（TBI）が脳梁に及ぼす影響を検討した発表でした．被験体としてマウスモデルを採用して，脳の詳細な構造の変化を確認していました．脳構造の解析にはDTIを用いて，FA値を確認していました．人の脳より小さいマウスの脳を対象とするため，高性能なMRIを用いて実験を行っていました．ただ，拡散強調傾斜磁場の軸数は30軸で，もう少し軸数を増やすべきではないかと思いました．
| 発表タイトル ： Sensitivity of mri measures to axonal and/or myelin repair in the presence of inflammation: a quantitative assessment of In vivo mtr, dti, and post-mortem immunohistochemistry in a rodent model of spontaneous remyelination 著者 ： B. A. Hooker セッション名 ： Neurotoxicity, Inflammation, and Neuroprotection Abstruct ： Magnetization Transfer (MT) imaging and Diffusion Tensor Imaging (DTI) are increasingly utilized in clinical trials of novel multiple sclerosis therapies. While measures derived from these techniques are sensitive to changes in white matter pathophysiology, they are also believed to be influenced by confounding factors such as changes in edema, typical in MS lesions, and thus limited in specificity. We investigated the sensitivity and specificity of in vivo MT ratio (MTR) and DTI measures to quantitative changes in myelin and axonal density in the presence of inflammation and edema assessed by immunohistochemistry (IHC). Focal demyelination was induced in Sprague Dawley rats (n=24) using stereotactic injection of 3uL of 1% lysophosphotidylcholine into the corpus callosum. DTI (380x380x500 μm, b~700 s/mm2, 30 directions) and MTR (250x250x500 μm, 9 μT Gaussian RF pulse, 2 kHz off-resonance) at 4.7T were acquired in three cross-sectional cohorts of animals at 14, 28, 56 days post injection (dpi), and sacrificed following image acquisition. Fractional anisotropy (FA), axial (AD), radial (RD), mean diffusivity (MD), T2 signal intensity and MTR maps were derived from the MR images. Brains were serially-sectioned and stained to assess myelin density (MBP), axonal density (NF1), inflammation (Iba1) and edema (IgG). Quantitative endpoints were derived from lesions manually delineated on MRI and IHC. Focal lesions were detected in all animals. Myelin and axonal pathology were highest at 14 dpi followed by spontaneous repair evidenced by improvement in MBP and NF1 staining (p<0.05) by 56 dpi. In line with the IHC findings, increase in MTR, FA and reduction in MD, RD and T2 were observed 56 dpi relative to 14 and 28 dpi (p<0.05). MTR and FA increased by 3 and 30%; MD, RD and T2 decreased by 4, 10 and 17% at 56 dpi relative to 14 dpi. The outcome of univariate and multivariate analysis to elucidate the magnitude of influence each underlying aspect of pathophysiology (myelin, axon, inflammation and edema) had on each MRI outcome measure will be reported along with strategies to minimize the influence of confounding factors in the interpretation of MRI outcome measures. The findings provide improved understanding of the pathophysiological sensitivity and specificity of MRI measures, aiding in the choice of optimal measures and their precise interpretation in clinical trials of remyelinating agents. |
この発表はDTI測定の感度を検討した発表でした．従来，多発性硬化症の検査にはDTIが利用されています．しかし，DTIは白質の変化には敏感ですが，浮腫の変化を検知するのは困難と成っているため，この発表では感度を検討していました． この発表では測定方法が及ぼす影響を表しているため，今後の多発性硬化症に関する研究でも応用されるものと思いました．
| 発表タイトル ： Combining diffusion tensor imaging and robotics to assess structural changes and sensorimotor recovery following sport-related concussion 著者 ： A. Champagne セッション名 ： Injury and TraumaⅡ Abstruct ： Following a concussion, or mild traumatic brain injury (mTBI), individuals experience a broad range of cognitive and motor deficits in the acute post-injury period. Evidence-based return-to-play guidelines are subjective in nature due to our current inability to properly monitor structural and functional recovery of the injured athlete. A quantitative understanding of the relationship between brain injury and motor deficits could provide objective guidelines for the clinical management of mTBIs. The purpose of this pilot project was to determine whether diffusion tensor imaging (DTI) and robotics could be used to quantify recovery patterns following sport-related concussion.To investigate the structural and behavioral changes following mTBI, we collected imaging and sensorimotor data (using the KINARMTM robot) at two time points (<14 days and 3 months), post-injury. Four injured varsity athletes (20.5±0.6 years, 3M) were recruited following mTBI, while ten non-injured athletes (19.9±2.0 years, 5M) served as controls. To determine structural changes in white matter (WM), we performed a region-of-interest analysis in ten bilateral tracts defined using the John Hopkins University DTI-based WM tractography atlas. The mean fractional anisotropy (FA) for each tract was compared between the acute (<14 days) and follow-up (3 months) time points using a paired t-test. The behavioral changes were examined by selecting parameters from the sensorimotor tasks where the injured groups fell outside of the normative range (5 to 95%). These parameters included the task score and median error score from the Object Hit and Avoid task, which recruits higher executive functions such as attention, rapid motor selection and inhibition. Parameter scores were averaged among the groups and compared to the controls to look for signs of recovery. The imaging results showed a significant increase in FA (p=0.0035) within the superior longitudinal fasciculus (SLF) of the acute group when compared to the 3 months follow up. Additionally, the task and median error scores showed improvements at 3 months post-injury as they both closely approached the averaged scores from the controls. After 3 months, injured subjects hence performed better and made fewer errors in the first half of the task compared to when they were initially tested after sustaining a concussion. Although preliminary, these results suggest possible associations between WM changes and deficits in visuospatial processing after mTBI, followed by recovery. This provides exciting potential for the combined use of neuroimaging and cutting-edge robotics to assess recovery after concussion. |
この発表はスポーツ関連の脳震盪の回復パターンの定量化にDTIとロボット技術を利用できるか判断した発表でした．DTIで脳の構造的変化，KINARMTMロボットを利用して感覚運動データを収集していました．結果として，軽度な外傷性脳障害後の白質の変化と視空間の処理には関連性がある可能性が示唆されていました．DTIと運動感覚の関連性を検討した論文を見たことがありませんでしたが．非常に興味深い内容でした．似たような研究を研究室内の設備で行う場合，Tobiiを用いてできることはないか考えていました．
参考文献
- Society for Neuroscience，https://www.sfn.org/annual-meeting/neuroscience-2016